Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

Longitudinal immunological characterization of the first presensitized recipient of a face transplant

Rejection affects greater than 80% of face transplants, yet no diagnostic criteria for antibody-mediated rejection (AMR) following face transplantation have been established. Given that different treatment strategies are required to address AMR and T cell-mediated rejection (TCMR), there is a critical need to delineate the features that can differentiate these two alloimmune responses. Here, we report the longitudinal immunological examination of what we believe to be the first and only highly sensitized recipient of a crossmatch-positive face transplant up to 4 years following transplantation. We conducted gene expression profiling on allograft biopsies collected during suspected AMR and TCMR episodes as well as during 5 nonrejection time points. Our data suggest that there are distinctive molecular features in AMR, characterized by overexpression of endothelial-associated genes, including ICAM1, VCAM1, and SELE. Although our findings are limited to a single patient, these findings highlight the potential importance of developing and implementing molecular markers to differentiate AMR from TCMR to guide clinical management. Furthermore, our case illustrates that molecular assessment of allograft biopsies offers the potential for new insights into the mechanisms underlying rejection. Finally, our medium-term outcomes demonstrate that face transplantation in a highly sensitized patient with a positive preoperative crossmatch is feasible and manageable.

Abstract IA23: Cervical tissue T cells in HPV disease

Despite the availability of preventative vaccines, human papillomaviruses (HPVs) cause more cancers than any other virus. Like other viral pathogens that cause human cancers, most HPV infections do not cause overt harm, let alone symptoms. Indeed, in immune-competent persons, most genital infections are eventually cleared. Nonetheless, the incidence of HPV-associated cancers in anatomic sites for which no screening algorithms have been validated is rising steadily. Preinvasive, intraepithelial lesions are associated with integration of the HPV genome into the host genome, and subsequent expression of the viral oncoproteins, E6 and E7, which are required for disease initiation and persistence. These true tumor-specific antigens provide non-“self” targets for immune therapies. The relatively indolent clinical course of preinvasive lesions, and tissue tropism of HPV infections provide opportunities to identify and treat early stage disease.

In cervical HPV disease, a subset of high grade dysplastic lesions, cervical intraepithelial neoplasia grade 3 (CIN3), do in fact undergo complete regression, which is presumably immunologically mediated. However, T cell responses to viral antigens, measured in the blood, have not been informative with respect to immune responses in the cervical mucosa.

Our team has been studying strategies to enhance the quality and magnitude of immune responses to HPV antigens. Ongoing clinical trials testing therapeutic vaccination and strategies to manipulate the lesion microenvironment to enhance homing and access of immune effector cells will be discussed. The design of these trials has been informed by studies of tissue-resident T cells in normal cervical mucosa, and by changes identified in dysplastic mucosa, both in lesions that regress, and in those that do not, in the course of a defined, prospective study window. Changes in the composition and distribution of tissue T cells postvaccination will be presented. Strategies to modify the stromal compartment of HPV lesions to promote lesion clearance will also be discussed.

Citation Format: C.L. Trimble, J. Teague, T.C. Wu, R.A. Clark. Cervical tissue T cells in HPV disease. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr IA23.

BioMart Central Portal: an open database network for the biological community

BioMart Central Portal is a first of its kind, community-driven effort to provide unified access to dozens of biological databases spanning genomics, proteomics, model organisms, cancer data, ontology information and more. Anybody can contribute an independently maintained resource to the Central Portal, allowing it to be exposed to and shared with the research community, and linking it with the other resources in the portal. Users can take advantage of the common interface to quickly utilize different sources without learning a new system for each. The system also simplifies cross-database searches that might otherwise require several complicated steps. Several integrated tools streamline common tasks, such as converting between ID formats and retrieving sequences. The combination of a wide variety of databases, an easy-to-use interface, robust programmatic access and the array of tools make Central Portal a one-stop shop for biological data querying. Here, we describe the structure of Central Portal and show example queries to demonstrate its capabilities.

Human papillomavirus 16-associated cervical intraepithelial neoplasia in humans excludes CD8 T cells from dysplastic epithelium

High-grade cervical dysplasia caused by human papillomavirus (HPV) type 16 is a lesion that should be susceptible to an HPV-specific immune response; disease initiation and persistence is predicated on expression of two viral Ags, E6 and E7. In immune-competent subjects, at least 25% of HPV16(+) high-grade cervical dysplasia lesions undergo complete regression. However, in the peripheral blood, naturally occurring IFN-γ T cell responses to HPV E6 and E7 are weak, requiring ex vivo sensitization to detect, and are not sufficiently sensitive to predict regression. In this study, we present immunologic data directly assessing cervical lymphocytes from this cohort. We found that nearly all cervical tissue T cells express the mucosal homing receptor, α(4)β(7) surface integrin. T cells isolated from dysplastic mucosa were skewed toward a central memory phenotype compared with normal mucosal resident T cells, and dysplastic lesions expressed transcripts for CCL19 and CCL21, raising the possibility that the tissue itself sustains a response that is not detectable in the blood. Moreover, lesion regression in the study window could retrospectively be predicted at study entry by the ability of CD8(+) T cells to gain access to lesional epithelium. Vascular endothelial expression of mucosal addressin cell adhesion molecule-1, the ligand that supports entry of α(4)β(7)(+) T cells into tissues, colocalized tightly with the distribution of CD8 T cells and was not expressed in persistent dysplastic epithelium. These findings suggest that dysregulated expression of vascular adhesion molecules plays a role in immune evasion very early in the course of HPV disease.

Cervical mucosal CD8 T cells are more predictive of HPV lesion regression than systemic HPV-specific response (48.13)

Virtually all squamous cervical cancers and their dysplastic precursor lesions (CIN2/3), are caused by infection with human papillomavirus (HPV), most commonly, HPV16. Although 20-25% of HPV16+ CIN2/3 undergo complete regression, HPV16-specific T cell immunity in blood is only marginally detectable, and does not correlate with lesion regression. To better understand immunity within the cervical microenvironment, we studied T cells and the expression of vascular adhesion receptors in normal and dysplastic human cervical mucosa. The majority of CIN2/3 CD8+ T cells had an activated memory phenotype, and nearly all expressed α4β7. Regression was predicted by lesional intraepithelial CD8 T cells, whereas in persistent disease, CD8 T cells were restricted to the lesional subepithelial stroma. Expression of VCAM-1 and MAdCAM-1, two ligands that support the entry of α4β7+ T cells into tissues, correlated with CD8 infiltrates. Our data provide evidence that reduced adhesion receptor expression on CIN2/3 vasculature may restrict the entry of CD8 T cells into dysplastic mucosa, thereby preventing immunologic clearance. Immune therapies for cervical dysplasia should generate CD8 T cells that express α4β7, and include local manipulation to induce vascular expression of adhesion receptors that can support the entry of these cells into lesional epithelium.

Somatic mutation databases as tools for molecular epidemiology and molecular pathology of cancer: proposed guidelines for improving data collection, distribution, and integration

There are currently less than 40 locus-specific databases (LSDBs) and one large general database that curate data on somatic mutations in human cancer genes. These databases have different scope and use different annotation standards and database systems, resulting in duplicated efforts in data curation, and making it difficult for users to find clear and consistent information. As data related to somatic mutations are generated at an increasing pace it is urgent to create a framework for improving the collecting of this information and making it more accessible to clinicians, scientists, and epidemiologists to facilitate research on biomarkers. Here we propose a data flow for improving the connectivity between existing databases and we provide practical guidelines for data reporting, database contents, and annotation standards. These proposals are based on common standards recommended by the Human Genome Variation Society (HGVS) with additions related to specific requirements of somatic mutations in cancer. Indeed, somatic mutations may be used in molecular pathology and clinical studies to characterize tumor types, help treatment choice, predict response to treatment and patient outcome, or in epidemiological studies as markers for tumor etiology or exposure assessment. Thus, specific annotations are required to cover these diverse research topics. This initiative is meant to promote collaboration and discussion on these issues and the development of adequate resources that would avoid the loss of extremely valuable information generated by years of basic and clinical research.

An assessment of the in vivo efficacy of the glycogen phosphorylase inhibitor GPi688 in rat models of hyperglycaemia

BACKGROUND AND PURPOSE

Studies in cultured hepatocytes demonstrate glycogen synthase (GS) activation with glycogen phosphorylase (GP) inhibitors. The current study investigated whether these phenomena occurred in vivo using a novel GP inhibitor.

EXPERIMENTAL APPROACH

An allosteric GP inhibitor, GPi688, was evaluated against both glucagon-mediated hyperglycaemia and oral glucose challenge-mediated hyperglycaemia to determine the relative effects against GP and GS in vivo.

KEY RESULTS

In rat primary hepatocytes, GPi688 inhibited glucagons-mediated glucose output in a concentration dependent manner. Additionally GP activity was reduced and GS activity increased seven-fold. GPi688 inhibited glucagon-mediated hyperglycaemia in both Wistar (65%) & obese Zucker (100%) rats and demonstrated a long duration of action in the Zucker rat. The in vivo efficacy in the glucagon challenge model could be predicted by the equation; % glucagon inhibition=56.9+34.3[log ([free plasma]/rat IC50)], r=0.921). GPi688 also reduced the blood glucose of obese Zucker rats after a 7 h fast by 23%. In an oral glucose tolerance test in Zucker rats, however, GPi688 was less efficacious (7% reduction) than a glycogen synthase kinase-3 (GSK-3) inhibitor (22% reduction), despite also observing activation (by 45%) of GS in vivo.

CONCLUSIONS AND IMPLICATIONS

Although GP inhibition can inhibit hyperglycaemia mediated by increased glucose production, the degree of GS activation induced by allosteric GP inhibitors in vivo, although discernible, is insufficient to increase glucose disposal. The data suggests that GP inhibitors might be more effective clinically against fasting rather than prandial hyperglycaemic control.

Mutations in the RSK2(RPS6KA3) gene cause Coffin-Lowry syndrome and nonsyndromic X-linked mental retardation

We describe three families with X-linked mental retardation, two with a deletion of a single amino acid and one with a missense mutation in the proximal domain of the RSK2(RPS6KA3) (ribosomal protein S6 kinase, 90 kDa, polypeptide 3) protein similar to mutations found in Coffin-Lowry syndrome (CLS). In two families, the clinical diagnosis had been nonsyndromic X-linked mental retardation. In the third family, although CLS had been suspected, the clinical features were atypical and the degree of intellectual disability much less than expected. These families show that strict reliance on classical clinical criteria for mutation testing may result in a missed diagnosis. A less targeted screening approach to mutation testing is advocated.

Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus

Idiopathic congenital nystagmus is characterized by involuntary, periodic, predominantly horizontal oscillations of both eyes. We identified 22 mutations in FRMD7 in 26 families with X-linked idiopathic congenital nystagmus. Screening of 42 singleton cases of idiopathic congenital nystagmus (28 male, 14 females) yielded three mutations (7%). We found restricted expression of FRMD7 in human embryonic brain and developing neural retina, suggesting a specific role in the control of eye movement and gaze stability.

COSMIC 2005

The Catalogue Of Somatic Mutations In Cancer (COSMIC) database and web site was developed to preserve somatic mutation data and share it with the community. Over the past 25 years, approximately 350 cancer genes have been identified, of which 311 are somatically mutated. COSMIC has been expanded and now holds data previously reported in the scientific literature for 28 known cancer genes. In addition, there is data from the systematic sequencing of 518 protein kinase genes. The total gene count in COSMIC stands at 538; 25 have a mutation frequency above 5% in one or more tumour type, no mutations were found in 333 genes and 180 are rarely mutated with frequencies <5% in any tumour set. The COSMIC web site has been expanded to give more views and summaries of the data and provide faster query routes and downloads. In addition, there is a new section describing mutations found through a screen of known cancer genes in 728 cancer cell lines including the NCI-60 set of cancer cell lines.

The COSMIC (Catalogue of Somatic Mutations in Cancer) database and website

The discovery of mutations in cancer genes has advanced our understanding of cancer. These results are dispersed across the scientific literature and with the availability of the human genome sequence will continue to accrue. The COSMIC (Catalogue of Somatic Mutations in Cancer) database and website have been developed to store somatic mutation data in a single location and display the data and other information related to human cancer. To populate this resource, data has currently been extracted from reports in the scientific literature for somatic mutations in four genes, BRAF, HRAS, KRAS2 and NRAS. At present, the database holds information on 66 634 samples and reports a total of 10 647 mutations. Through the web pages, these data can be queried, displayed as figures or tables and exported in a number of formats. COSMIC is an ongoing project that will continue to curate somatic mutation data and release it through the website.

Chloride channels regulate HIT cell volume but cannot fully account for swelling-induced insulin secretion

Insulin-secreting pancreatic islet beta-cells possess anion-permeable Cl- channels (I(Cl,islet)) that are swelling-activated, but the role of these channels in the cells is unclear. The Cl- channel blockers 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and niflumic acid were evaluated for their ability to inhibit I(Cl,islet) in clonal beta-cells (HIT cells). Both drugs blocked the channel, but the blockade due to niflumic acid was less voltage-dependent than the blockade due to DIDS. HIT cell volume initially increased in hypotonic solution and was followed by a regulatory volume decrease (RVD). The addition of niflumic acid and, to a lesser extent, DIDS to the hypotonic solution potentiated swelling and blocked the RVD. In isotonic solution, niflumic acid produced swelling, suggesting that islet Cl- channels are activated under basal conditions. The channel blockers glyburide, gadolinium, or tetraethylammonium-Cl did not alter hypotonic-induced swelling or volume regulation. The Na/K/2Cl transport blocker furosemide produced cell shrinkage in isotonic solution and blocked cell swelling normally induced by hypotonic solution. Perifused HIT cells secreted insulin when challenged with hypotonic solutions. However, this could not be completely attributed to I(Cl,islet)-mediated depolarization, because secretion persisted even when Cl- channels were fully blocked. To test whether blocker-resistant secretion occurred via a distal pathway, distal secretion was isolated using 50 mmol/l potassium and diazoxide. Under these conditions, glucose-dependent secretion was blunted, but hypotonically induced secretion persisted, even with Cl- channel blockers present. These results suggest that beta-cell swelling stimulates insulin secretion primarily via a distal I(Cl,islet)-independent mechanism, as has been proposed for K(ATP)-independent glucose- and sulfonylurea-stimulated insulin secretion. Reverse transcriptase-polymerase chain reaction of HIT cell mRNA identified a CLC-3 transcript in HIT cells. In other systems, CLC-3 is believed to mediate swelling-induced outwardly rectifying Cl- channels. This suggests that the proximal effects of swelling to regulate cell volume may be mediated by CLC-3 or a closely related Cl- channel.

Attenuation of insulin secretion by insulin-like growth factor 1 is mediated through activation of phosphodiesterase 3B

Both insulin and insulin-like growth factor 1 (IGF-1) are known to reduce glucose-dependent insulin secretion from the beta cells of pancreatic islets. In this paper we show that the mechanism by which IGF-1 mediates this effect is in large part through activation of a specific cyclic nucleotide phosphodiesterase, phosphodiesterase 3B (PDE3B). More specifically, in both isolated pancreatic islets and insulin-secreting HIT-T15 cells, IGF-1 inhibits insulin secretion that has been increased by glucose and glucagonlike peptide 1 (GLP-1). Moreover, IGF-1 decreases cAMP levels in parallel to the reduction of insulin secretion. Insulin secretion stimulated by cAMP analogs that activate protein kinase A and also are substrates for PDE3B is also inhibited by IGF-1. However, IGF-1 does not inhibit insulin secretion stimulated by nonhydrolyzable cAMP analogs. In addition, selective inhibitors of PDE3B completely block the ability of IGF-1 to inhibit insulin secretion. Finally, PDE3B activity measured in vitro after immunoprecipitation from cells treated with IGF-1 is higher than the activity from control cells. Taken together with the fact that pancreatic beta cells express little or no insulin receptor but large amounts of IGF-1 receptor, these data strongly suggest a new regulatory feedback loop model for the control of insulin secretion. In this model, increased insulin secretion in vivo will stimulate IGF-1 synthesis by the liver, and the secreted IGF-1 in turn feedback inhibits insulin secretion from the beta cells through an IGF-1 receptor-mediated pathway. This pathway is likely to be particularly important when levels of both glucose and secretagogues such as GLP-1 are elevated.

A metric map of humans: 23,500 loci in 850 bands

High-resolution maps integrated with the enhanced location data base software (LDB+) give improved estimates of genetic parameters and reveal characteristics of cytogenetic bands. Chiasma interference is intermediate between Kosambi and Carter-Falconer levels, as in Drosophila and the mouse. The autosomal genetic map is 2832 and 4348 centimorgans in males and females, respectively. Telomeric T-bands are strikingly associated with male recombination and gene density. Position and centromeric heterochromatin have large effects, but nontelomeric R-bands are not significantly different from G-bands. Several possible reasons are discussed. These regularities validate the maps, despite their high resolution and inevitable local errors. No other approach has been demonstrated to integrate such a large number of loci, which are increasing at about 45% per year. The maps and the data and software from which they are constructed are available through the Internet (http:@cedar.genetics.soton.ac.uk/public_html). Successive versions of this location data base may also be accessed on CD-ROM.

Linkage map integration

The algorithms that drive the map+ program for locus-oriented linkage mapping are presented. They depend on the enhanced location database program ldb+ to specify an initial comprehensive map that includes all loci in the summary lod file. Subsequently the map may be edited or order constrained and is automatically improved by estimating the location of each locus conditional on the remainder, beginning with the most discrepant loci. Operating characteristics permit rapid and accurate construction of linkage maps with several hundred loci. The map+ program also performs nondisjunction mapping with tests of nonstandard recombination. We have released map+ on Internet as a source program in the C language together with the location database that now includes the LODSOURCE database. The anonymous ftp is cedar.genetics.soton.ac.uk and the World Wide Web address is http://cedar.genetics.soton.ac.uk/public_html.

Contribution of L- and non-L-type calcium channels to voltage-gated calcium current and glucose-dependent insulin secretion in HIT-T15 cells

The pharmacological properties of voltage-gated Ca current and glucose-dependent insulin secretion were determined using the HIT insulinoma line to understand the role of Ca channels in stimulus-secretion coupling. The L-type Ca channel antagonist nimodipine inhibited a maximum of 50-55% of the peak Ca current, suggesting that L- and non-L-type channels contribute to Ca current. The L-agonist BAY K 8644 increased Ca current by 155%, whereas the N-channel blocker omega-conotoxin MVIIA reversibly blocked 35% of the peak Ca current. Total block with nimodipine and MVIIA was additive. Conotoxin MVIIC did not affect HIT Ca current. Prolonged depolarizations elicited rapidly and slowly inactivating Ca currents. Nimodipine partially inhibited transient current, but fully inhibited slowly inactivating current, suggesting that the former is mediated by L- and N-channels, and the latter is mediated by L-channels. Like slowly inactivating Ca current, glucose-dependent insulin secretion was fully inhibited by nimodipine and insensitive to MVIIA. BAY K potentiated secretion and antagonized nimodipine block. These results suggest that persistent Ca current is mediated by L-channels and is strongly coupled to insulin secretion, whereas transient Ca current is mediated by L- and N-channels and is weakly coupled. Sustained Ca influx may be preferentially coupled because glucose persistently depolarizes HIT cells and inactivates more transient Ca channel pathways.

The reproductive and neural toxicities of acrylamide and three analogues in Swiss mice, evaluated using the continuous breeding protocol

Acrylamide is a known genetic, reproductive, and neural toxicant, although it is not known if one effect is predominant. The toxicities of several structural analogues of acrylamide have been incompletely characterized, and the relative sensitivity of the second generation is not known. The present studies were designed to explore the relationship between neurotoxicity and reproductive toxicity, to further characterize the toxicities of three acrylamide analogues, and to evaluate the relative sensitivity of a second generation to these compounds. For the F0 generation, male and female Swiss CD-1 mice were provided drinking water containing acrylamide (ACR; 3, 10, 30 ppm), N,N'-methylenebisacrylamide (MBA; 10, 30, 60 ppm), N-(hydroxymethyl)acrylamide (HMA; 60, 180, 360 ppm), or methacrylamide (MACR; 24, 80, 240 ppm) during and after a 14-week cohabitation. The last litter was reared and dosed after weaning until mating at 74 +/- 10 days of age with the same level of compound given to the parents Neurotoxicity was assessed at several times in both generations by measuring forelimb and hindlimb grip strength. In the F0 generation, ACR caused an 11% decrease in pup number without measurable neurotoxicity; female fertility was not affected. Although both generations consumed the same amount of ACR, there were larger changes in the fertility-related endpoints in the F1 mice than in the F0's, with no concomitant change in organ weights or sperm parameters. In F0 mice, MBA reduced the number of live pups and their adjusted weight, with no neurotoxicity and no change in F0 female reproduction. MBA caused greater adverse effects in the second generation, concomitant with increased consumption. In the F0 generation, HMA caused the largest decrease in pup number during cohabitation (26%) together with a small effect on grip strength. Female reproduction was not affected. The second generation consumed more HMA and showed slightly greater toxic effects. In both generations, MACR was negative for both neurotoxicity and reproductive toxicity. Dominant-lethal studies showed that the fertility effects for ACR, MBA, and HMA could be explained by a male-mediated increase in postimplantation loss. These studies found that dominant lethality occurred without structural effects on the reproductive system in the presence of only minor effects on grip strength and without detectable neural histopathology. Female reproduction was not significantly affected by these compounds at the doses used. Thus, these data confirm the male as the affected gender and that the reproductive toxicity was greater than motoneuron toxicity when measured as grip strength.

Regulation of glutamic acid decarboxylase diabetes autoantigen expression in highly purified isolated islets from Macaca nemestrina

Macaca nemestrina, which may have larger and more numerous pancreatic islets than other species, was used for large scale islet isolation by ductal collagenase perfusion and Ficoll gradient centrifugation. The average yield was 51,000 islet equivalents per pancreas, or 8,750 islets equivalents per g. The average purity was 91%, often exceeding 95%. These are the highest reported size, purity, and yield per g of any nonautomated primate islet series. Perifusion with glucose, arginine, and isobutylmethylxanthine showed appropriate biphasic insulin secretion. Unlike that in the rat, human islet glutamic acid decarboxylase (GAD) isoform expression is restricted. However, glycemic regulation of GAD expression has been shown only in rats. We, therefore, tested hypotheses that M. nemestrina islets also have restricted GAD expression, that GAD expression in primates is stimulated by glucose, and that this stimulation remains restricted to the 64,000 mol wt (GAD65) isoform. Immunoprecipitation of labeled islet extracts showed that GAD65 expression increased 16.7 +/- 0.6-fold during high glucose in vitro culture. After controlling for observed increases in protein synthesis, specific glucose stimulation was still 4.2 +/- 0.2-fold. Specific antisera revealed no GAD67 expression under basal conditions, and isoform restriction was maintained during stimulation. Increased GAD65 synthesis thus accounts for glucose stimulation of 64K expression. These time- and concentration-dependent effects of glucose suggest that hyperglycemia increases autoantigenicity and may accelerate beta-cell destruction in primates, supporting a role for beta-cell rest in insulin-dependent diabetes mellitus prevention.

Novel, rapid optical immunoassay technique for detection of group A streptococci from pharyngeal specimens: comparison with standard culture methods

A novel immunoassay system based on the changes in the reflection of light, termed an optical immunoassay (OIA), was utilized to directly detect group A streptococcal (GAS) carbohydrate antigen from clinical specimens. In two studies, a total of 1,275 throat swabs were tested for the presence of this antigen with the Strep A OIA rapid detection system and the results were compared with those of standard culture methods. In both studies, the Strep A OIA yielded more positive results than plating of the throat swab onto a selective agar, Trypticase soy agar containing sheep blood, or an enriched broth. In one study, the sensitivity and specificity of Strep A OIA compared with those of the broth-enriched culture were 97.4 and 95.6%, respectively. In a second study a sensitivity of 98.9% and a specificity of 98.6% were achieved. It was also shown that the carbohydrate antigen could be detected in the absence of viable GAS organisms. The Strep A OIA is an easily interpretable method and was shown to be more sensitive than routine culture methods for detecting GAS infections directly from throat swabs.

Reproductive toxicity assessment by continuous breeding in Sprague-Dawley rats: a comparison of two study designs

The protocol for Reproductive Assessment by Continuous Breeding (RACB) studies was originally designed to use mice as the test species. However, rats are commonly used for reproductive toxicity research and could be used in the basic RACB design. One of the studies reported below evaluated a standard murine RACB design using rats, which rears the fifth litter to test second generation fertility. The second design tested the logistics and feasibility of rearing the second litter for second generation fertility testing. The standard fifth litter design (L5) was modified slightly for rats by increasing the time allowed for gestation and delivery. Compared to rats rearing their second litter (L2), rats in this L5 design had more litters per pair during continuous breeding and maintained this fertility better over time, as evidenced by producing more pups per litter during the crossover mating segment. Both L2 and L5 rats gave sufficient pups to conduct the second generation fertility evaluation. In addition, the L5 design was easier to conduct and produced pups from gametes exposed to chemical throughout spermatogenesis, making it the preferred design for using rats in Continuous Breeding studies.

Phasic effects of glucose, p-hydroxymercuribenzoate, and lysophosphatidylcholine on insulin secretion from HIT cells

Monolayer cultures of HIT cells were superfused to examine phasic insulin secretion. A biphasic pattern of insulin secretion was observed when cells were stimulated with a constant glucose concentration as low as 0.28 mM, with increasing stimulation at 0.56, 1.7, and 5.6 mM glucose. Higher glucose concentrations did not increase insulin secretion. In the absence of glucose, p-hydroxymercuribenzoate (15, 30, and 50 microM), which blocks the reacylation of lysophospholipids with arachidonic acid, also evoked a concentration-dependent biphasic release of insulin. Lysophosphatidylcholine (50, 75, and 100 micrograms/ml) also caused a concentration-dependent biphasic release of insulin in the absence of glucose. These observations were similar to those previously reported for superfused monolayer culture of rat islet cells and suggest that the HIT cell is a beta-cell line that may be valuable in the further examination of the relationships among glucose, phospholipid metabolism, and insulin secretion. The data are consistent with the hypothesis that glucose-stimulated release of lysophospholipids may be important in initiation of the biphasic pattern of glucose-stimulated insulin release.

Reproductive effects of four phthalic acid esters in the mouse

These studies compared the reproductive toxicity of four phthalates by a continuous breeding protocol. Mice were given diets with diethyl phthalate (DEP) (0.0, 0.25, 1.25, or 2.5%), di-n-butyl phthalate (DBP) (0.0, 0.03, 0.3, or 1.0%), di-n-hexyl phthalate (DHP) (0.0, 0.3, 0.6, or 1.2%), or di(2-ethylhexyl) phthalate (DEHP) (0.0, 0.01, 0.1, or 0.3%). Both male and female CD-1 mice were dosed for 7 days prior to and during a 98-day cohabitation period. Reproductive function was evaluated during the cohabitation period by measuring the numbers of litters per pair and of live pups per litter, pup weight, and offspring survival. There was no apparent effect on reproductive function in the animals exposed to DEP, despite significant effects on body weight gain and liver weight. DBP exposure resulted in a reduction in the numbers of litters per pair and of live pups per litter and in the proportion of pups born alive at the 1.0% amount, but not at lower dose levels. A crossover mating trial demonstrated that female mice, but not males, were affected by DBP, as shown by significant decreases in the percentage of fertile pairs, the number of live pups per litter, the proportion of pups born alive, and live pup weight. DHP in the diet resulted in dose-related adverse effects on the numbers of litters per pair and of live pups per litter and proportion of pups born alive at 0.3, 0.6, and 1.2% DHP in the diet. A crossover mating study demonstrated that both sexes were affected. DEHP (at 0.1 and 0.3%) caused dose-dependent decreases in fertility and in the number and the proportion of pups born alive. A crossover mating trial showed that both sexes were affected by exposure to DEHP. These data demonstrate the ability of the continuous breeding protocol to discriminate the qualitative and quantitative reproductive effects of the more and less active congeners as well as the large differences in reproductive toxicity attributable to subtle changes in the alkyl substitution of phthalate esters.

A medical evaluation of the use of qat in North Yemen

The data presented in this paper examine the frequent statements that the regular use of the drug qat by the people of North Yemen is harmful to their health. The research strategy employed performance of blind physical examinations as well as extensive interviews with 335 females and 371 males in and around the cities of Sanaa, Taiz and Hodeida who had been selected using a quota sample. The sample was classified into heavy, light and non-chewers of the qat plant, and systematic comparisons were made. In general, few diseases or conditions occurred with enough frequency to permit detailed analysis and fewer yet were associated with qat-use. Where associations occurred, differences by sex were often strong. Conditions most strongly associated with use by both sexes were histories of gastritis and insomnia, and the general body system groupings of gastrointestinal disorders. In males the strongest associations were with the histories of anorexia, constipation, insomnia and headaches, as well as the general history of respiratory difficulties. In females strong associations were seen between qat-use and the diagnosis of acute gastritis, and histories of jaundice, bronchitis and hepatic diseases. When effects of age and residence were corrected for by Mantel-Haenszel odds ratios on these items, some of the associations were diminished even further. In general, remarkably few of the allegations regarding the direct effects of qat-use on health by Western visitors to Yemen were supported by this study.

Qat use in North Yemen and the problem of addiction: a study in medical anthropology

Travelers to North Yemen nearly invariably report that Yemeni people are universally addicted to the drug qat and that the problems of the country are related to this. On the other hand, the majority of Yemenis claim that qat is not only harmless, but that it has many virtues. After describing the chemistry of the drug and the customs of use, this paper addresses the question of the concept of addiction in terms of data gathered during an extensive field study of qat use. Questions of latency, tolerance and availability are discussed, while particular attention and data are devoted to an examination of the "analgesic hypothesis." It is concluded that a more complex theory is needed to deal with drug "dependencies" and that social and cultural perspectives must be added to concepts of the physiological and psychological effects of drugs if progress is to be made toward understanding institutional drug use such as is found with regard to qat.

Fibroblast monolayer cultures in scintillation counting vials: metabolic and growth experiments using radioisotopes and a microfluoremetric DNA assay

We have developed a simple technique for the investigation of cellular metabolism and growth in cultured human fibroblasts which facilitates experiments using up to 3 x 10(5) cells in each of 100 or more culture vessels. The method has been used to study cell growth, glucose utilization and oxidation, and protein, RNA and DNA sysnthesis. The use of radiolabeled substrates in tracer experiments is simplified since transfer of cell material is not required. Methods for measuring both total cellular protein and DNA have been adapted to this culture system. Although we have used this tecnique for fibroblast cultures, it also can be easily applied to experiments on any other type of cell that can be grown in a monolayer.

Monolayer cell culture of human pancreatic beta cell tumor: effect of glucose and somatostatin on insulin release

A human pancreatic beta cell tumor was maintained in monolayer cell culture for 80 days. The culture was terminated because of bacterial infection. Probably because extensive trypsin-collagenase dissociation was unnecessary, the dissociated cells attached much more quickly to the surface of the culture flask than do rat pancreatic cells obtained by enzymatic dissociation. Insulin release not only oscillated widely during the first 40 days of culture but also showed a decline from 380 mU the first week to about 50 mU/week the seventh week. For some unknown reason fibroblast overgrowth was not a major problem. Reduction of the medium glucose concentration from 16.5 mM to 5.5 mM did not alter insulin release rate. At glucose concentration of 16.5 mM, somatostatin 1.0 mug/ml reduced insulin release by 40%. From our previously reported studies on the effect of somatostatin on insulin release by monolayer cell cultures of rat endocrine pancreas, we conclude that the constant release of insulin by the tumor cells is relatively nonstimulated. We have confirmed that monolayer cultures of human pancreatic beta cell tumor do not represent a good model for normal human beta cell function because of the major shortcoming of an apparent inability to recognize glucose as a secretogogue.