BACKGROUND

Huntington's disease (HD) is a fatal and progressive neurodegenerative disease that is accompanied by involuntary movements, cognitive dysfunction, and psychiatric symptoms. Although progressive striatal degeneration is known to occur, little is known about how the disease affects the cortex, including which cortical regions are affected, how degeneration proceeds, and the relationship of the cortical degeneration to clinical symptoms. The cortex has been difficult to study in neurodegenerative diseases primarily because of its complex folding patterns and regional variability; however, an understanding of how the cortex is affected by the disease may provide important new insights into it.

METHODS

Novel automated surface reconstruction and high-resolution MR images of 11 patients with HD and 13 age-matched subjects were used to obtain cortical thickness measurements. The same analyses were performed on two postmortem brains to validate these methods.

RESULTS

Regionally specific heterogeneous thinning of the cortical ribbon was found in subjects with HD. Thinning occurred early, differed among patients in different clinical stages of disease, and appeared to proceed from posterior to anterior cortical regions with disease progression. The sensorimotor region was statistically most affected. Measurements performed on MR images of autopsy brains analyzed similarly were within 0.25 mm of those obtained using traditional neuropathologic methods and were statistically indistinguishable.

CONCLUSIONS

The authors propose that the cortex degenerates early in disease and that regionally selective cortical degeneration may explain the heterogeneity of clinical expression in HD. These measures might provide a sensitive prospective surrogate marker for clinical trials of neuroprotective medications.

Involvement of the hippocampus and caudate nucleus in place and response learning was examined by functionally inactivating these brain regions bilaterally with infusions of lidocaine. Rats were trained to approach a consistently baited arm in a cross-maze from the same start box (four trials/day/14 total days). On Days 8 and 16 a single probe trial was given, in which rats were placed in the start box opposite that used in training and allowed to approach a maze arm. Three minutes prior to the probe trial, rats received bilateral injections of either saline or a 2% lidocaine solution (in order to produce neural inactivation) into either the dorsal hippocampus or dorsolateral caudate nucleus. On the probe trials, rats which entered the baited maze arm (i.e., approached the place where food was located during training) were designated place learners, and rats which entered the unbaited maze arm (i.e., made the same turning response as during training) were designated response learners. Saline-treated rats displayed place learning on the Day 8 probe trial and response learning on the Day 16 probe trial, indicating that with extended training there is a shift in learning mechanisms controlling behavior. Rats given lidocaine injections into the hippocampus showed no preference for place or response learning on the Day 8 probe trial, but displayed response learning on the Day 16 probe trial, indicating a blockade of place learning following inactivation of the hippocampus. Rats given lidocaine injections into the caudate nucleus displayed place learning on both the Day 8 and the Day 16 probe trials, indicating a blockade of response learning following inactivation of the caudate nucleus. The findings indicate: (1) the hippocampus and caudate nucleus selectively mediate expression of place and response learning, respectively (2), in a visually cued extramaze environment, hippocampal-dependent place learning is acquired faster than caudate-dependent response learning, and (3) when animals shift to caudate-dependent response learning with extended training, the hippocampal-based place representation remains intact.

Three strains of enteropathogenic Escherichia coli (EPEC), originally isolated from humans and previously shown to cause diarrhea in human volunteers by unknown mechanisms, and one rabbit EPEC strain were shown to attach intimately to and efface microvilli and cytoplasm from intestinal epithelial cells in both the pig and rabbit intestine. The attaching and effacing activities of these EPEC were demonstrable by light microscopic examination of routine histological sections and by transmission electron microscopy. It was suggested that intact colostrum-deprived newborn pigs and ligated intestinal loops in pigs and rabbits may be useful systems to detect EPEC that have attaching and effacing activities and for studying the pathogenesis of such infections. The lesions (attachment and effacement) produced by EPEC in these systems were multifocal, with considerable animal-to-animal variation in response to the same strain of EPEC. The EPEC strains also varied in the frequency and extent of lesion production. For example, three human EPEC strains usually caused extensive lesions in rabbit intestinal loops, whereas two other human EPEC strains usually did not produce lesions in this system.

Two genomic clones (lambda Ubi-1 and lambda Ubi-2) encoding the highly conserved 76 amino acid protein ubiquitin have been isolated from maize. Sequence analysis shows that both genes contain seven contiguous direct repeats of the protein coding region in a polyprotein conformation. The deduced amino acid sequence of all 14 repeats is identical and is the same as for other plant ubiquitins. The use of transcript-specific oligonucleotide probes shows that Ubi-1 and Ubi-2 are expressed constitutively at 25 degrees C but are inducible to higher levels at elevated temperatures in maize seedlings. Both genes contain an intron in the 5' untranslated region which is inefficiently processed following a brief, severe heat shock. The transcription start site of Ubi-1 has been determined and a transcriptional fusion of 0.9 kb of the 5' flanking region and the entire 5' untranslated sequence of Ubi-1 with the coding sequence of the gene encoding the reporter molecule chloramphenicol acetyl transferase (CAT) has been constructed (pUBI-CAT). CAT assays of extracts of protoplasts electroporated with this construct show that the ubiquitin gene fragment confers a high level of CAT expression in maize and other monocot protoplasts but not in protoplasts of the dicot tobacco. Expression from the Ubi-1 promoter of pUBI-CAT yields more than a 10-fold higher level of CAT activity in maize protoplasts than expression from the widely used cauliflower mosaic virus 35S promoter of a 35S-CAT construct. Conversely, in tobacco protoplasts CAT activity from transcription of pUBI-CAT is less than one tenth of the level from p35S-CAT.

In a variety of plant species, the development of necrotic lesions in response to pathogen infection leads to induction of generalized disease resistance in uninfected tissues. A well-studied example of this "immunity" reaction is systemic acquired resistance (SAR) in tobacco. SAR is characterized by the development of a disease-resistant state in plants that have reacted hypersensitively to previous infection by tobacco mosaic virus. Here, we show that the onset of SAR correlates with the coordinate induction of nine classes of mRNAs. Salicylic acid, a candidate for the endogenous signal that activates the resistant state, induces expression of the same "SAR genes." A novel synthetic immunization compound, methyl-2,6-dichloroisonicotinic acid, also induces both resistance and SAR gene expression. These observations are consistent with the hypothesis that induced resistance results at least partially from coordinate expression of these SAR genes. A model is presented that ties pathogen-induced necrosis to the biosynthesis of salicylic acid and the induction of SAR.

BACKGROUND

The McCune-Albright syndrome is a sporadic disease characterized by polyostotic fibrous dysplasia, café au lait spots, sexual precocity, and hyperfunction of multiple endocrine glands. These manifestations may be explained by a somatic mutation in affected tissues that results in activation of the signal-transduction pathway generating cyclic AMP (cAMP). We analyzed DNA from tissues of patients with the McCune-Albright syndrome for the presence of activating mutations of the gene for the alpha subunit of the G protein (Gs alpha) that stimulates cAMP formation.

METHODS

Genomic DNA fragments encompassing regions (exons 8 and 9) previously found to contain activating missense mutations of the Gs alpha gene (gsp mutations) in sporadically occurring pituitary tumors were amplified in tissues from four patients with the McCune-Albright syndrome by the polymerase chain reaction. The amplified DNA was analyzed for mutations by denaturing gradient gel electrophoresis and allele-specific oligonucleotide hybridization.

RESULTS

We detected one of two activating mutations within exon 8 of the Gs alpha gene in tissues from all four patients, including affected endocrine organs (gonads, adrenal glands, thyroid, and pituitary) and tissues not classically involved in the McCune-Albright syndrome. In two of the patients, histidine was substituted for arginine at position 201 of Gs alpha, and in the other two patients cysteine was substituted for the same arginine residue. In each patient the proportion of cells affected varied from tissue to tissue. In two endocrine organs, the highest proportion of mutant alleles was found in regions of abnormal cell proliferation.

CONCLUSIONS

Mutations within exon 8 of the Gs alpha gene that result in increased activity of the Gs protein and increased cAMP formation are present in various tissues of patients with the McCune-Albright syndrome. Somatic mutation of this gene early in embryogenesis could result in the mosaic population of normal and mutant-bearing tissues that may underlie the clinical manifestations of this disease.

BACKGROUND

Hand hygiene prevents cross infection in hospitals, but compliance with recommended instructions is commonly poor. We attempted to promote hand hygiene by implementing a hospital-wide programme, with special emphasis on bedside, alcohol-based hand disinfection. We measured nosocomial infections in parallel.

METHODS

We monitored the overall compliance with hand hygiene during routine patient care in a teaching hospital in Geneva, Switzerland, before and during implementation of a hand-hygiene campaign. Seven hospital-wide observational surveys were done twice yearly from December, 1994, to December, 1997. Secondary outcome measures were nosocomial infection rates, attack rates of methicillin-resistant Staphylococcus aureus (MRSA), and consumption of handrub disinfectant.

RESULTS

We observed more than 20,000 opportunities for hand hygiene. Compliance improved progressively from 48% in 1994, to 66% in 1997 (p<0.001). Although recourse to handwashing with soap and water remained stable, frequency of hand disinfection substantially increased during the study period (p<0.001). This result was unchanged after adjustment for known risk factors of poor adherence. Hand hygiene improved significantly among nurses and nursing assistants, but remained poor among doctors. During the same period, overall nosocomial infection decreased (prevalence of 16.9% in 1994 to 9.9% in 1998; p=0.04), MRSA transmission rates decreased (2.16 to 0.93 episodes per 10,000 patient-days; p<0.001), and the consumption of alcohol-based handrub solution increased from 3.5 to 15.4 L per 1000 patient-days between 1993 and 1998 (p<0.001).

CONCLUSIONS

The campaign produced a sustained improvement in compliance with hand hygiene, coinciding with a reduction of nosocomial infections and MRSA transmission. The promotion of bedside, antiseptic handrubs largely contributed to the increase in compliance.

Recent work has shown that there may be disadvantages in the use of the chi-square-like goodness-of-fit tests for the logistic regression model proposed by Hosmer and Lemeshow that use fixed groups of the estimated probabilities. A particular concern with these grouping strategies based on estimated probabilities, fitted values, is that groups may contain subjects with widely different values of the covariates. It is possible to demonstrate situations where one set of fixed groups shows the model fits while the test rejects fit using a different set of fixed groups. We compare the performance by simulation of these tests to tests based on smoothed residuals proposed by le Cessie and Van Houwelingen and Royston, a score test for an extended logistic regression model proposed by Stukel, the Pearson chi-square and the unweighted residual sum-of-squares. These simulations demonstrate that all but one of Royston's tests have the correct size. An examination of the performance of the tests when the correct model has a quadratic term but a model containing only the linear term has been fit shows that the Pearson chi-square, the unweighted sum-of-squares, the Hosmer-Lemeshow decile of risk, the smoothed residual sum-of-squares and Stukel's score test, have power exceeding 50 per cent to detect moderate departures from linearity when the sample size is 100 and have power over 90 per cent for these same alternatives for samples of size 500. All tests had no power when the correct model had an interaction between a dichotomous and continuous covariate but only the continuous covariate model was fit. Power to detect an incorrectly specified link was poor for samples of size 100. For samples of size 500 Stukel's score test had the best power but it only exceeded 50 per cent to detect an asymmetric link function. The power of the unweighted sum-of-squares test to detect an incorrectly specified link function was slightly less than Stukel's score test. We illustrate the tests within the context of a model for factors associated with low birth weight.

BACKGROUND

Obstructive sleep apnea (OSA) is a major risk factor for perioperative adverse events. However, no screening tool for OSA has been validated in surgical patients. This study was conducted to develop and validate a concise and easy-to-use questionnaire for OSA screening in surgical patients.

METHODS

After hospital ethics approval, preoperative patients aged 18 yr or older and without previously diagnosed OSA were recruited. After a factor analysis, reliability check, and pilot study; four yes/no questions were used to develop this screening tool. The four questions were respectively related to snoring, tiredness during daytime, observed apnea, and high blood pressure (STOP). For validation, the score from the STOP questionnaire was evaluated versus the apnea-hypopnea index from monitored polysomnography.

RESULTS

The STOP questionnaire was given to 2,467 patients, 27.5% classified as being at high risk of OSA. Two hundred eleven patients underwent polysomnography, 34 for the pilot test and 177 for validation. In the validation group, the apnea-hypopnea index was 20 +/- 6. The sensitivities of the STOP questionnaire with apnea-hypopnea index greater than 5, greater than 15, and greater than 30 as cutoffs were 65.6, 74.3, and 79.5%, respectively. When incorporating body mass index, age, neck circumference, and gender into the STOP questionnaire, sensitivities were increased to 83.6, 92.9, and 100% with the same apnea-hypopnea index cutoffs.

CONCLUSIONS

The STOP questionnaire is a concise and easy-to-use screening tool for OSA. It has been developed and validated in surgical patients at preoperative clinics. Combined with body mass index, age, neck size, and gender, it had a high sensitivity, especially for patients with moderate to severe OSA.

BACKGROUND

Despite increasing awareness about the potential impact of financial conflicts of interest on biomedical research, no comprehensive synthesis of the body of evidence relating to financial conflicts of interest has been performed.

OBJECTIVE

To review original, quantitative studies on the extent, impact, and management of financial conflicts of interest in biomedical research.

METHODS

Studies were identified by searching MEDLINE (January 1980-October 2002), the Web of Science citation database, references of articles, letters, commentaries, editorials, and books and by contacting experts.

METHODS

All English-language studies containing original, quantitative data on financial relationships among industry, scientific investigators, and academic institutions were included. A total of 1664 citations were screened, 144 potentially eligible full articles were retrieved, and 37 studies met our inclusion criteria.

METHODS

One investigator (J.E.B.) extracted data from each of the 37 studies. The main outcomes were the prevalence of specific types of industry relationships, the relation between industry sponsorship and study outcome or investigator behavior, and the process for disclosure, review, and management of financial conflicts of interest.

RESULTS

Approximately one fourth of investigators have industry affiliations, and roughly two thirds of academic institutions hold equity in start-ups that sponsor research performed at the same institutions. Eight articles, which together evaluated 1140 original studies, assessed the relation between industry sponsorship and outcome in original research. Aggregating the results of these articles showed a statistically significant association between industry sponsorship and pro-industry conclusions (pooled Mantel-Haenszel odds ratio, 3.60; 95% confidence interval, 2.63-4.91). Industry sponsorship was also associated with restrictions on publication and data sharing. The approach to managing financial conflicts varied substantially across academic institutions and peer-reviewed journals.

CONCLUSIONS

Financial relationships among industry, scientific investigators, and academic institutions are widespread. Conflicts of interest arising from these ties can influence biomedical research in important ways.

There are no gender differences in depression rates in prepubescent children, but, after the age of 15, girls and women are about twice as likely to be depressed as boys and men. In this article, three models for how gender differences in depression might develop in early adolescence are described and evaluated. According to Model 1, the causes of depression are the same for girls and boys, but these causes become more prevalent in girls than in boys in early adolescence. According to Model 2, there are different causes of depression in girls and boys, and the causes of girls' depression become more prevalent than the causes of boys' depression in early adolescence. According to Model 3, girls are more likely than boys to carry risk factors for depression even before early adolescence, but these risk factors lead to depression only in the face of challenges that increase in prevalence in early adolescence. Most studies of gender differences in depression have focused on the effects of individual variables on depression in girls and boys rather than on testing models of how these differences develop. Evidence for the variables most commonly thought to contribute to gender differences in depression in children and adolescents is reviewed, and this evidence is related to the three models for how these differences develop. It is concluded that Model 3 is best supported by the available data, although much more research is needed. Before adolescence, girls appear to develop more risk factors for depression than boys; girls also apparently face more new challenges in early adolescence than boys. It is argued that these factors combine, as specified in Model 3, to generate gender differences in depression beginning in early adolescence.

The Child Feeding Questionnaire (CFQ) is a self-report measure to assess parental beliefs, attitudes, and practices regarding child feeding, with a focus on obesity proneness in children. Confirmatory factor analysis tested a 7-factor model, which included four factors measuring parental beliefs related to child's obesity proneness, and three factors measuring parental control practices and attitudes regarding child feeding. Using a sample of 394 mothers and fathers, three models were tested, and the third model confirmed an acceptable fit, including correlated factors. Internal consistencies for the seven factors were above 0.70. With minor changes, this same 7-factor model was also confirmed in a second sample of 148 mothers and fathers, and a third sample of 126 Hispanic mothers and fathers. As predicted, four of the seven factors were related to an independent measure of children's weight status, providing initial support for the validity of the instrument. The CFQ can be used to assess aspects of child-feeding perceptions, attitudes, and practices and their relationships to children's developing food acceptance patterns, the controls of food intake, and obesity. The CFQ is designed for use with parents of children ranging in age from about 2 to 11 years of age.

Transcriptional repression by Mad-Max heterodimers requires interaction of Mad with the corepressors mSin3A/B. Sin3p, the S. cerevisiae homolog of mSin3, functions in the same pathway as Rpd3p, a protein related to two recently identified mammalian histone deacetylases, HDAC1 and HDAC2. Here, we demonstrate that mSin3A and HDAC1/2 are associated in vivo. HDAC2 binding requires a conserved region of mSin3A capable of mediating transcriptional repression. In addition, Mad1 forms a complex with mSin3 and HDAC2 that contains histone deacetylase activity. Trichostatin A, an inhibitor of histone deacetylases, abolishes Mad repression. We propose that Mad-Max functions by recruiting the mSin3-HDAC corepressor complex that deacetylates nucleosomal histones, producing alterations in chromatin structure that block transcription.

Anti-neutrophil cytoplasmic autoantibodies have been found in patients with systemic arteritis and glomerulonephritis. We studied the disease distribution and antigen specificity of these autoantibodies. Anti-neutrophil cytoplasmic autoantibodies were identified by indirect immunofluorescence microscopy in 27 of 35 patients with idiopathic necrotizing and crescentic glomerulonephritis, in whom the manifestations of disease ranged from injury limited to the kidney to systemic arteritis. The incidence and titers of the autoantibodies did not differ between patients with disease limited to the kidney and those with systemic disease. Anti-neutrophil immunostaining was detected in 5 of 11 patients with lupus nephritis, 4 of 71 patients with other renal diseases, and none of 50 normal controls. This distribution of autoantibodies was confirmed by an enzyme-linked immunosorbent assay (ELISA) using neutrophil lysate as antigen. According to ELISA, anti-neutrophil cytoplasmic autoantibodies were found to be specific for constituents of primary granules. Two types of autoantibodies were identified; one with reactivity with myeloperoxidase on ELISA produced an artifactual perinuclear immunostaining of alcohol-fixed neutrophils, and another with no reactivity with myeloperoxidase on ELISA produced diffuse cytoplasmic immunostaining. The presence of the same serologic marker in patients with kidney-limited and arteritis-associated necrotizing and crescentic glomerulonephritis, including Wegener's granulomatosis and polyarteritis nodosa, suggests that these clinically diverse diseases may have a similar pathogenesis, initiated by autoantibody-mediated activation of neutrophils.

To identify previously unknown genetic loci associated with fasting glucose concentrations, we examined the leading association signals in ten genome-wide association scans involving a total of 36,610 individuals of European descent. Variants in the gene encoding melatonin receptor 1B (MTNR1B) were consistently associated with fasting glucose across all ten studies. The strongest signal was observed at rs10830963, where each G allele (frequency 0.30 in HapMap CEU) was associated with an increase of 0.07 (95% CI = 0.06-0.08) mmol/l in fasting glucose levels (P = 3.2 x 10(-50)) and reduced beta-cell function as measured by homeostasis model assessment (HOMA-B, P = 1.1 x 10(-15)). The same allele was associated with an increased risk of type 2 diabetes (odds ratio = 1.09 (1.05-1.12), per G allele P = 3.3 x 10(-7)) in a meta-analysis of 13 case-control studies totaling 18,236 cases and 64,453 controls. Our analyses also confirm previous associations of fasting glucose with variants at the G6PC2 (rs560887, P = 1.1 x 10(-57)) and GCK (rs4607517, P = 1.0 x 10(-25)) loci.

In both type 1 and type 2 diabetes, diabetic complications in target organs arise from chronic elevations of glucose. The pathogenic effect of high glucose, possibly in concert with fatty acids, is mediated to a significant extent via increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and subsequent oxidative stress. ROS and RNS directly oxidize and damage DNA, proteins, and lipids. In addition to their ability to directly inflict damage on macromolecules, ROS and RNS indirectly induce damage to tissues by activating a number of cellular stress-sensitive pathways. These pathways include nuclear factor-kappaB, p38 mitogen-activated protein kinase, NH(2)-terminal Jun kinases/stress-activated protein kinases, hexosamines, and others. In addition, there is evidence that in type 2 diabetes, the activation of these same pathways by elevations in glucose and free fatty acid (FFA) levels leads to both insulin resistance and impaired insulin secretion. Therefore, we propose here that the hyperglycemia-induced, and possibly FFA-induced, activation of stress pathways plays a key role in the development of not only the late complications in type 1 and type 2 diabetes, but also the insulin resistance and impaired insulin secretion seen in type 2 diabetes.

The variation in gene frequency among populations or between generations within a population is a result of breeding structure and selection. But breeding structure should affect all loci and alleles in the same way. If there is significant heterogeneity between loci in their apparent inbreeding coefficients F=s(p) (2)/p(1-p), this heterogeneity may be taken as evidence for selection. We have given the statistical properties of F and shown how tests of heterogeneity can be made. Using data from human populations we have shown highly significant heterogeneity in F values for human polymorphic genes over the world, thus demonstrating that a significant fraction of human polymorphisms owe their current gene frequencies to the action of natural selection. We have also applied the method to temporal variation within a population for data on Dacus oleae and have found no significant evidence of selection.

The identification of mutations that are present in a small fraction of DNA templates is essential for progress in several areas of biomedical research. Although massively parallel sequencing instruments are in principle well suited to this task, the error rates in such instruments are generally too high to allow confident identification of rare variants. We here describe an approach that can substantially increase the sensitivity of massively parallel sequencing instruments for this purpose. The keys to this approach, called the Safe-Sequencing System ("Safe-SeqS"), are (i) assignment of a unique identifier (UID) to each template molecule, (ii) amplification of each uniquely tagged template molecule to create UID families, and (iii) redundant sequencing of the amplification products. PCR fragments with the same UID are considered mutant ("supermutants") only if ≥95% of them contain the identical mutation. We illustrate the utility of this approach for determining the fidelity of a polymerase, the accuracy of oligonucleotides synthesized in vitro, and the prevalence of mutations in the nuclear and mitochondrial genomes of normal cells.

How sister kinetochores attach to microtubules from opposite spindle poles during mitosis (bi-orientation) remains poorly understood. In yeast, the ortholog of the Aurora B-INCENP protein kinase complex (Ipl1-Sli15) may have a role in this crucial process, because it is necessary to prevent attachment of sister kinetochores to microtubules from the same spindle pole. We investigated IPL1 function in cells that cannot replicate their chromosomes but nevertheless duplicate their spindle pole bodies (SPBs). Kinetochores detach from old SPBs and reattach to old and new SPBs with equal frequency in IPL1+ cells, but remain attached to old SPBs in ipl1 mutants. This raises the possibility that Ipl1-Sli15 facilitates bi-orientation by promoting turnover of kinetochore-SPB connections until traction of sister kinetochores toward opposite spindle poles creates tension in the surrounding chromatin.

There is an increasing interest in using microRNAs (miRNA) as biomarkers in autoimmune diseases. They are easily accessible in many body fluids but it is controversial if they are circulating freely or are encapsulated in microvesicles, particularly exosomes. We investigated if the majority of miRNas in serum and saliva are free-circulating or concentrated in exosomes. Exosomes were isolated by ultracentrifugation from fresh and frozen human serum and saliva. The amount of selected miRNAs extracted from the exosomal pellet and the exosome-depleted serum and saliva was compared by quantitative RT-PCR. Some miRNAs tested are ubiquitously expressed, others were previously reported as biomarkers. We included miRNAs previously reported to be free circulating and some thought to be exosome specific. The purity of exosome fraction was confirmed by electronmicroscopy and western blot. The concentration of miRNAs was consistently higher in the exosome pellet compared to the exosome-depleted supernatant. We obtained the same results using an equal volume or equal amount of total RNA as input of the RT-qPCR. The concentration of miRNA in whole, unfractionated serum, was between the exosomal pellet and the exosome-depleted supernatant. Selected miRNAs, which were detectable in exosomes, were undetectable in whole serum and the exosome-depleted supernantant. Exosome isolation improves the sensitivity of miRNA amplification from human biologic fluids. Exosomal miRNA should be the starting point for early biomarker studies to reduce the probability of false negative results involving low abundance miRNAs that may be missed by using unfractionated serum or saliva.

Nanomaterials (NM) exhibit novel physicochemical properties that determine their interaction with biological substrates and processes. Three metal oxide nanoparticles that are currently being produced in high tonnage, TiO(2), ZnO, and CeO(2), were synthesized by flame spray pyrolysis process and compared in a mechanistic study to elucidate the physicochemical characteristics that determine cellular uptake, subcellular localization, and toxic effects based on a test paradigm that was originally developed for oxidative stress and cytotoxicity in RAW 264.7 and BEAS-2B cell lines. ZnO induced toxicity in both cells, leading to the generation of reactive oxygen species (ROS), oxidant injury, excitation of inflammation, and cell death. Using ICP-MS and fluorescent-labeled ZnO, it is found that ZnO dissolution could happen in culture medium and endosomes. Nondissolved ZnO nanoparticles enter caveolae in BEAS-2B but enter lysosomes in RAW 264.7 cells in which smaller particle remnants dissolve. In contrast, fluorescent-labeled CeO(2) nanoparticles were taken up intact into caveolin-1 and LAMP-1 positive endosomal compartments, respectively, in BEAS-2B and RAW 264.7 cells, without inflammation or cytotoxicity. Instead, CeO(2) suppressed ROS production and induced cellular resistance to an exogenous source of oxidative stress. Fluorescent-labeled TiO(2) was processed by the same uptake pathways as CeO(2) but did not elicit any adverse or protective effects. These results demonstrate that metal oxide nanoparticles induce a range of biological responses that vary from cytotoxic to cytoprotective and can only be properly understood by using a tiered test strategy such as we developed for oxidative stress and adapted to study other aspects of nanoparticle toxicity.

Gene replacement via homologous double crossover in filamentous fungi requires relatively long (preferentially >0.5 kb) flanking regions of the target gene. For this reason, gene replacement cassettes are usually constructed through multiple cloning steps. To facilitate gene function studies in filamentous fungi avoiding tedious cloning steps, we have developed a PCR-assisted DNA assembly procedure and applied it to delete genes in filamentous fungi. While the principle of this procedure is essentially the same as other recently reported PCR-based tools, our technique has been effectively used to delete 31 genes in three fungal species. Moreover, this PCR-based method was used to fuse more than 10 genes to a controllable promoter. In this report, a detailed protocol for this easy to follow procedure and examples of genes deleted or over-expressed are presented. In conjunction with the availability of genome sequences, the application of this technique should facilitate functional characterization of genes in filamentous fungi. To stream line the analysis of the transformants a relatively simple procedure for genomic DNA or total RNA isolation achieving approximately 100 samples/person/day is also presented.

BACKGROUND

Overweight adults are at an increased risk of developing numerous chronic diseases.

METHODS

Ten-year follow-up (1986-1996) of middle-aged women in the Nurses' Health Study and men in the Health Professionals Follow-up Study to assess the health risks associated with overweight.

RESULTS

The risk of developing diabetes, gallstones, hypertension, heart disease, and stroke increased with severity of overweight among both women and men. Compared with their same-sex peers with a body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) between 18.5 and 24.9, those with BMI of 35.0 or more were approximately 20 times more likely to develop diabetes (relative risk [RR], 17.0; 95% confidence interval [CI], 14.2-20.5 for women; RR, 23.4; 95% CI, 19.4-33.2 for men). Women who were overweight but not obese (ie, BMI between 25.0 and 29.9) were also significantly more likely than their leaner peers to develop gallstones (RR, 1.9), hypertension (RR, 1.7), high cholesterol level (RR, 1.1), and heart disease (RR, 1.4). The results were similar in men.

CONCLUSIONS

During 10 years of follow-up, the incidence of diabetes, gallstones, hypertension, heart disease, colon cancer, and stroke (men only) increased with degree of overweight in both men and women. Adults who were overweight but not obese (ie, 25.0 < or = BMI < or = 29.9) were at significantly increased risk of developing numerous health conditions. Moreover, the dose-response relationship between BMI and the risk of developing chronic diseases was evident even among adults in the upper half of the healthy weight range (ie, BMI of 22.0-24.9), suggesting that adults should try to maintain a BMI between 18.5 and 21.9 to minimize their risk of disease.

Rats were implanted with 0.3-mm-diameter dialysis tubing through the hippocampus and subsequently perfused with Ringer's solution at a flow rate of 2 microliter/min. Samples of the perfusate representing the extracellular fluid were collected over 5-min periods and subsequently analyzed for contents of the amino acids glutamate, aspartate, glutamine, taurine, alanine, and serine. Samples were collected before, during, and after a 10-min period of transient complete cerebral ischemia. The extracellular contents of glutamate and aspartate were increased, respectively, eight- and threefold during the ischemic period; the taurine concentration also was increased 2.6-fold. During the same period the extracellular content of glutamine was significantly decreased (to 68% of the control value), whereas the concentrations of alanine and serine did not change significantly during the ischemic period. The concentrations of gamma-aminobutyric acid (GABA) were too low to be measured reliably. It is suggested that the large increase in the content of extracellular glutamate and aspartate in the hippocampus induced by the ischemia may be one of the causal factors in the damage to certain neurons observed after ischemia.