Mechanisms and impact of enteric infections

The increased recognition of both old and new enteric pathogens and their potential impact requires an improved understanding of pathogenesis and effective interventions. While the overwhelming mortality (> 3 million children per year) due to diarrheal diseases is well-recognized, the potential long-term impacts of enteric infections and early childhood diarrhea morbidity are just beginning to be appreciated. Furthermore, several enteric infections are now being recognized as causes of growth shortfalls with or without diarrhea; i.e., malnutrition may be one of the greatest yet of the "emerging infectious diseases." The increased appreciation of this extended impact calls for further quantification and improved understanding of the deranged physiology. In particular, persistent diarrheal illnesses exhibit common themes of blunted villi, disruption of intestinal barrier function and varying degrees of sub-mucosal inflammation for which lactulose/mannitol permeability and fecal lactoferrin provide respective quantification. Finally, such improved understanding will allow targeted interventions among those most vulnerable, which will enable further documentation of cost effectiveness and the potential for improved human development which is critical to reducing the widening disparity and population overgrowth which increasingly threaten our global security.

Daily intermittent decreases in serum levels of parathyroid hormone have an anabolic-like action on the bones of uremic rats with low-turnover bone and osteomalacia

The calcium receptor agonist (calcimimetic) compound NPS R-568 causes rapid decreases in circulating levels of parathyroid hormone (PTH) in rats and humans. We hypothesized that daily intermittent decreases in serum PTH levels may have different effects on bone than do chronically sustained decreases. To test this hypothesis, we compared two NPS R-568 dosing regimens in rats with chronic renal insufficiency induced by two intravenous injections of adriamycin. Fourteen weeks after the second adriamycin injection, creatinine clearance was reduced by 52%, PTH levels were elevated approximately 2.5-fold, and serum 25(OH)D3 and 1,25(OH)2D3 levels were reduced substantially. Treatment by daily per os gavage, which decreased PTH levels intermittently, or continuous subcutaneous infusion, which resulted in a sustained suppression of serum PTH levels, then began for 8 weeks. Despite the hyperparathyroidism, the adriamycin-injected rats developed a low-turnover bone lesion with osteomalacia (fourfold increase in osteoid volume in the proximal tibial metaphysis) and osteopenia (67% decrease in cancellous bone volume and an 18% reduction in bone mineral density at the distal femur). Daily administered (but not infused) NPS R-568 significantly increased cancellous bone volume solely by normalizing trabecular thickness, and increased femoral bone mineral density by 14%. These results indicate that daily intermittent, but not sustained, decreases in PTH levels have an "anabolic-like" effect on bones with a low-turnover lesion in this animal model of chronic renal insufficiency.

25 years of Population Trends

This article monitors some of the more significant demographic changes over the last twenty-five years, depicted in various issues of Population Trends. It is, of necessity, selective in coverage in terms of quotes, figures and topics. Other articles in this issue go into more depth on specific topics, such as families, ethnic minority groups, marriage and divorce, health inequalities and fertility and family planning. Consequently, there is some overlap and the articles could usefully be cross-referenced. Some coverage is also given to the development of sources, international events and selected partnerships outside the Office. Relevant legislation enacted over the period is also mentioned.

Effect of carbohydrate ingestion on glycogen resynthesis in human liver and skeletal muscle, measured by (13)C MRS

This study investigated the effect of carbohydrate (CHO) ingestion on postexercise glycogen resynthesis, measured simultaneously in liver and muscle (n = 6) by (13)C magnetic resonance spectroscopy, and subsequent exercise capacity (n = 10). Subjects cycled at 70% maximal oxygen uptake for 83 +/- 8 min on six separate occasions. At the end of exercise, subjects ingested 1 g/kg body mass (BM) glucose, sucrose, or placebo (control). Resynthesis of glycogen over a 4-h period after treatment ingestion was measured on the first three occasions, and subsequent exercise capacity was measured on occasions four through six. No glycogen was resynthesized during the control trial. Liver glycogen resynthesis was evident after glucose (13 +/- 8 g) and sucrose (25 +/- 5 g) ingestion, both of which were different from control (P < 0.01). No significant differences in muscle glycogen resynthesis were found among trials. A relationship between the CHO load (g) and change in liver glycogen content (g) was evident after 30, 90, 150, and 210 min of recovery (r = 0.59-0. 79, P < 0.05). Furthermore, a modest relationship existed between change in liver glycogen content (g) and subsequent exercise capacity (r = 0.53, P < 0.05). However, no significant difference in mean exercise time was found (control: 35 +/- 5, glucose: 40 +/- 5, and sucrose: 46 +/- 6 min). Therefore, 1 g/kg BM glucose or sucrose is sufficient to initiate postexercise liver glycogen resynthesis, which contributes to subsequent exercise capacity, but not muscle glycogen resynthesis.

Calcimimetic NPS R-568 prevents parathyroid hyperplasia in rats with severe secondary hyperparathyroidism

Calcimimetic NPS R-568 prevents parathyroid hyperplasia in rats with severe secondary hyperparathyroidism.

BACKGROUND

Secondary hyperparathyroidism (secondary HPT) in chronic renal insufficiency (CRI) is characterized by multiglandular hyperplasia.

METHODS

In this study, we investigated the effects of the calcimimetic NPS R-568 on the parathyroid gland in rats with CRI induced by ligation of the renal arteries and severe secondary HPT induced by dietary phosphorus loading. Six days after surgery, high-phosphorus diet feeding was started, and NPS R-568 was administered to the rats for 56 days either by daily gavage (30 or 100 micromol/kg) or by continuous subcutaneous infusion (20 micromol/kg. day).

RESULTS

After 54 days, serum PTH levels in vehicle-treated CRI rats were 1019 vs. 104 pg/mL in sham-operated controls. Infusion of NPS R-568 maintained serum PTH at levels comparable with those of sham-operated controls, whereas daily gavage also prevented much of the increase in CRI controls and decreased PTH levels intermittently in a dose-dependent fashion. Parathyroid gland enlargement was caused predominantly by hyperplasia. Total cell number per kg body wt was 3.5-fold higher in vehicle-treated CRI rats than in sham-operated controls. Both infusion and high-dose gavage of NPS R-568 completely prevented the increase in parathyroid cell number.

CONCLUSION

These results demonstrate that the calcimimetic compound NPS R-568 can prevent both the increase in serum PTH levels and parathyroid hyperplasia in rats with CRI and severe secondary HPT. Moreover, these changes occurred despite decreases in serum 1, 25(OH)2D3 and increases in serum phosphate, suggesting a dominant role for the calcium receptor in regulating parathyroid cell proliferation.

CADMIUM II: acquisition and representation of radiological knowledge for computerized decision support in mammography

CADMIUM II is a system for the interpretation of mammograms. A novel aspect of the system is that it combines symbolic reasoning with image processing, in contrast with most other approaches, which use only image processing and rely on artificial neural networks (ANNs) to classify mammograms. A problem of ANNs is that the advice they give cannot be traced back to communicable diagnostic inferences. Our approach is to provide advice based on explicit knowledge about the diagnostic process. To this end, we have conducted a knowledge elicitation study which looked at the descriptors used by expert radiologists when making diagnostic decisions about mammograms. The analysis of the radiologists' reports yielded a set of salient diagnostic features. These were used to inform the advice provided by the symbolic decision making component of CADMIUM II.

Not just a pretty face: physical attractiveness and perfectionism in the risk for eating disorders

OBJECTIVE

Considerable research has examined the correlates and consequences of both objective and subjective ratings of physical attractiveness. Numerous studies have found, for example, that subjective physical attractiveness is inversely related to weight and diet concerns. Surprisingly, however, no research has examined the relationship between objective physical beauty and eating pathologies, despite clinical and theoretical reasons to expect a positive relationship between the two.

METHOD

We rated 203 young women on facial attractiveness and obtained self-report measures of perfectionism, neuroticism, and weight preoccupation.

RESULTS

Attractiveness was positively related to weight preoccupation after controlling for body size and neurotic perfectionism.

DISCUSSION

These findings provide the first evidence of physical beauty as a risk for disordered eating, and confirm earlier evidence that the relationship between general perfectionism and disordered eating only occurs when combined with a tendency to be anxious and hypercritical. Results are discussed in the context of identity formation and the attractiveness stereotype.

A quality and safety framework for point-of-care clinical guidelines

The electronic dissemination of medical knowledge in the form of executable clinical guidelines and decision support systems must be accompanied by comprehensive methods for ensuring the quality of their knowledge content and their safety in use. This paper outlines a set of quality and safety requirements, and reviews three current guideline technologies, the Arden Syntax, GLIF and PROforma, against these requirements. The approaches used in these technologies have different strengths, and we propose a general framework for ensuring quality and safety that combines them. This framework brings together the normal documentation standards of medical publishing, rigorous design methods from software engineering, and active safety management techniques from artificial intelligence.

The development and evaluation of CADMIUM: a prototype system to assist in the interpretation of mammograms

We have developed CADMIUM, a novel approach for the design of systems to assist in the interpretation of medical images. CADMIUM uses symbolic reasoning to relate information obtained from image processing to the decisions radiologists take. The approach is based on a symbolic decision procedure which has already been used successfully in a variety of nonimaging clinical decision systems. In CADMIUM this decision procedure is extended with models of three generic image interpretation tasks: detection, measurement and classification of image features. The extended procedure is used to construct the lines of reasoning needed in each task and to control the acquisition of information by image processing. CADMIUM has been evaluated as an aid to the differential diagnosis of microcalcifications on mammographic images. Radiographers who had been trained to interpret images performed better when using the advice provided by the system.

A common breakpoint on 11q23 in carriers of the constitutional t(11;22) translocation

Structural chromosomal rearrangements occur commonly in the general population. Individuals that carry a balanced translocation are at risk of having unbalanced offspring; therefore, the frequency of translocations in couples with recurrent spontaneous abortions is higher than that in the general population. The constitutional t(11;22) translocation is the most common recurrent non-Robertsonian translocation in humans and may serve as a model to determine the mechanism that causes recurrent meiotic translocations. We previously localized the t(11;22) translocation breakpoint to a region on 22q11 within a low-copy repeat, termed "LCR22." To define the breakpoint on 11q23 and to ascertain whether this region shares homology with LCR22 sequences, we performed haplotype analysis on patients with der(22) syndrome. We found that the breakpoint on 11q23 occurred between two genetic markers, D11S1340 and APOC3-tetra, both being present within a single bacterial-artificial-chromosome clone. To determine whether the breakpoint occurred within the same region among a larger set of carriers, we performed FISH mapping studies. The breakpoints were all within the same clone, suggesting that this region may harbor sequences that are prone to breakage. We narrowed the breakpoint interval, in both derivative chromosomes from two unrelated carriers, to a 190-bp, AT-rich repeat, which indicates that this repeat may mediate recombination events on chromosome 11. Interestingly, the LCR22s harbor AT-rich repeats, suggesting that this sequence motif may mediate recombination events in nonhomologous chromosomes during meiosis.

Calcimimetic compound NPS R-568 stimulates calcitonin secretion but selectively targets parathyroid gland Ca(2+) receptor in rats

N-(3-[2-Chlorophenyl]propyl)-(R)-alpha-methyl-3-methoxybenzylamine (NPS R-568) is an orally active compound that activates Ca(2+) receptors on parathyroid cells and rapidly suppresses plasma levels of parathyroid hormone (PTH) and Ca(2+) (ED(50), 1 and 10 mg/kg, respectively). We now show that increased calcitonin secretion contributes to NPS R-568-induced hypocalcemia. In parathyroidectomized thyroid-intact rats in which normocalcemia was restored by PTH infusion, NPS R-568 rapidly reduced plasma Ca(2+) levels, indicating that decreased PTH secretion was not solely responsible for the hypocalcemia seen in normal animals. NPS R-568 decreased plasma Ca(2+) levels in thyroidectomized parathyroid-intact rats, but the rate of onset of hypocalcemia was slower than in controls. In contrast, NPS R-568 had no effect on plasma Ca(2+) levels in PTH-infused, thyroparathyroidectomized rats, providing evidence that increased calcitonin secretion caused the hypocalcemia in PTH-infused parathyroidectomized rats. NPS R-568 rapidly increased plasma calcitonin levels to a peak at 10 to 20 min after oral dosing (ED(50) 40 mg/kg). NPS R-568 did not affect the rate of disappearance of (45)Ca from blood, indicating that hypocalcemia resulted from decreased influx of Ca(2+) into the circulation and not from increased efflux. This suggests that NPS R-568-induced hypocalcemia resulted solely from reduced efflux of Ca(2+) from bone after increased calcitonin and reduced PTH secretion. Thus, NPS R-568 causes hypocalcemia by activating Ca(2+) receptors on C cells and parathyroid cells; however, NPS R-568 is about 40 times more potent in reducing PTH levels than in increasing calcitonin levels.

NPS R-568: a type II calcimimetic compound that acts on parathyroid cell calcium receptor of rats to reduce plasma levels of parathyroid hormone and calcium

Calcimimetics like N-(3-[2-chlorophenyl]propyl)-(R)-alpha-methyl-3-methoxybenzylamine (NPS R-568) potentiate the effects of extracellular Ca(2+) on parathyroid Ca(2+) receptors and inhibit parathyroid hormone (PTH) secretion in vitro. When administered by gavage to normal rats in this study, NPS R-568 caused a rapid, dose-dependent (ED(50), 1.1 +/- 0.7 mg/kg) decrease in PTH levels that was paralleled by a subsequent decrease in plasma Ca(2+) (ED(50), 10.4 +/- 3.7 mg/kg). At higher doses (>/=3.3 mg/kg), PTH was reduced to a minimum level within 15 min, the duration of which was dose dependent. With doses of 10 to 100 mg/kg, the hypocalcemia was rapid in onset (<30 min) and, at 33 to 100 mg/kg, persisted for >24 h. Neither the magnitude nor the kinetics of the hypocalcemic response was affected by total nephrectomy, demonstrating that NPS R-568 does not induce hypocalcemia by acting on renal Ca(2+) receptors to increase Ca(2+) excretion. In contrast, parathyroidectomy (intact thyroid) abolished the hypocalcemic response to NPS R-568, regardless of whether the rats were hypocalcemic or rendered acutely normo- or hypercalcemic by calcium infusion before dosing. These data show that the parathyroid Ca(2+) receptor can be selectively activated in vivo with a small organic compound to decrease plasma levels of PTH and Ca(2+) and thus define the mechanism of action of this compound in vivo. Moreover, the data add pharmacological support to the view that the Ca(2+) receptor is the primary molecular entity regulating systemic Ca(2+) homeostasis.

FGF receptor availability regulates skeletal myogenesis

Fibroblast growth factors (FGFs) and their receptors are critical participants in embryonic development, including the genesis of skeletal, cardiac, and smooth muscle. FGF signaling is mediated through interactions between multiple FGF ligands and transmembrane tyrosine kinase receptors, resulting in activation of a number of signal transduction pathways. Skeletal myocytes express FGF ligands and receptors in a coordinated fashion, suggesting that these molecules participate in autocrine signaling in the myocyte. Endogenously produced FGF has been shown to inhibit myogenesis, but the role of FGF receptor availability in directing myocyte proliferation and differentiation has not been established. To determine the contribution of receptor availability to the regulation of myogenesis, receptor availability was either increased by expressing a full-length FGF receptor-1 or decreased by expressing a truncated FGF receptor-1 in cultured skeletal myocytes. Constitutive expression of a full-length FGF receptor-1 increased myocyte proliferation and delayed differentiation. Conversely, a reduction in functional FGF receptor signaling by expression of a truncated FGF receptor-1 decreased proliferation and enhanced differentiation of myocytes. These data demonstrate that FGF receptor availability plays a critical regulatory role in skeletal myogenesis.

Computer support for recording and interpreting family histories of breast and ovarian cancer in primary care (RAGs): qualitative evaluation with simulated patients

OBJECTIVES

To explore general practitioners' attitudes towards and use of a computer program for assessing genetic risk of cancer in primary care.

DESIGN

Qualitative analysis of semistructured interviews and video recordings of simulated consultations.

PARTICIPANTS

Purposive sample of 15 general practitioners covering a range of computer literacy, interest in genetics, age, and sex.

INTERVENTIONS

Each doctor used the program in two consultations in which an actor played a woman concerned about her family history of cancer. Consultations were videotaped and followed by interviews with the video as a prompt to questioning. MAIN OUTCOME MESURESs: Use of computer program in the Consultation.

RESULTS

The program was viewed as an appropriate application of information technology because of the complexity of cancer genetics and a sense of "guideline chaos" in primary care. Doctors found the program easy to use, but it often affected their control of the consultation. They needed to balance their desire to share the computer screen with the patient, driven by their concerns about the effect of the computer on doctor-patient communication, against the risk of premature disclosure of bad news.

CONCLUSIONS

This computer program could provide the necessary support to assist assessment of genetic risk of cancer in primary care. The potential impact of computer software on the consultation should not be underestimated. This study highlights the need for careful evaluation when developing medical information systems.

The effect of hysterectomy on the risk of an abnormal screening Papanicolaou test result

OBJECTIVE

Our aim was to determine the risk of cytologic abnormality on a screening Papanicolaou test for women >/=50 years old with and without a uterine cervix.

STUDY DESIGN

The effect of hysterectomy on abnormal screening Papanicolaou test rates was determined in a cross-sectional analysis of 21,152 women aged >/=50 years who had screening Papanicolaou tests between January and August 1995. We then conducted a nested 1:1 case-control study of 172 case patients and 172 age-matched randomly selected control patients from the cohort. To control for potential confounders, conditional logistic regression was used to assess the effect of hysterectomy status on the risk of an abnormal Papanicolaou test.

RESULTS

Compared with age-matched women with a uterine cervix, those who had a hysterectomy had a 10-fold lower risk of a screening Papanicolaou test abnormality (odds ratio 0.09, 95% confidence interval 0.02-0.24). The risk was further reduced among women taking estrogens (odds ratio 0.02, 95% confidence interval 0.004-0.14) compared with women not using estrogens (odds ratio 0.14, 95% confidence interval 0.04-0.56).

CONCLUSIONS

The reduced risk of Papanicolaou test abnormalities among women aged >/=50 years who have had a hysterectomy should be considered when individual patients are being counseled, screening guidelines are being formulated, and health care resources are being allocated.

The calcimimetic NPS R-568 decreases plasma PTH in rats with mild and severe renal or dietary secondary hyperparathyroidism

NPS R-568 is a Ca2+ receptor agonist ("calcimimetic") compound that reduces circulating parathyroid hormone (PTH) levels in rats and humans with mild secondary hyperparathyroidism (secondary HPT) resulting from chronic renal insufficiency (CRI). These studies extend those observations to show that NPS R-568 is equally effective in decreasing plasma PTH and Ca2+ levels in rats with mild or severe secondary HPT, resulting either from CRI or from dietary calcium deficiency. Male rats were 5/6 nephrectomized and fed either normal chow or a high-phosphorus diet; other normal rats were fed a low-calcium diet. When secondary HPT had developed, NPS R-568 was administered and blood samples were collected for up to 6 h. PTH levels decreased to a minimum level within 30 min in both CRI and calcium deficiency models of secondary HPT. PTH and Ca2+ levels remained significantly depressed for >3 h after dosing. The percentage decrease in PTH levels was unaffected by the severity of secondary HPT or the basal plasma Ca2+ or phosphate levels. In rats with severe secondary HPT, the minimum plasma PTH level after NPS R-568 was greater than the basal level in mild secondary HPT. Thus, NPS R-568 is equally effective in suppressing plasma PTH and Ca2+ levels in rats with mild or severe renal or nutritional secondary HPT.

Mosaicism with a normal cell line and an unbalanced structural rearrangement

Mosaicism with a normal cell line (N) and an unbalanced autosomal structural rearrangement (UASR) is rare. This report describes a case of a newborn female with a karyotype of 46,XX,der(4)t(4;15)(q35;q22)/46,XX. Molecular cytogenetic analysis confirmed the origin of the derivative chromosome 4. Here we discuss this case as well as other cases of mosaic karyotypes involving N/UASR.

Metal working fluid-associated hypersensitivity pneumonitis: an outbreak investigation and case-control study

Occupational exposure to bacterial or fungal antigens has been associated with hypersensivity pneumonitis (HP), an immunologically-mediated pulmonary disease. Between August 1995 and April 1996, 34 employees working in machining and assembly areas of an engine manufacturing plant were clinically diagnosed with HP. Of these, 20 employees met an epidemiologic case definition. In a case-control study, no exposure variables, including duration and intensity of metal working fluid (MWF) exposure, were statistically associated with an increased risk of disease. Neither cases nor controls demonstrated precipitin reactivity against unused samples of the seven MWF and two biocides used in the plant. HP cases had a significantly higher prevalence of positive precipitin reactions to used oil soluble and synthetic MWFs. Reactivity to used but not unused MWF suggests a biocontaminant, probably bacteria or fungi, is the causative antigen in the development of HP in this setting.

The inherited long QT syndrome: from ion channel to bedside

The inherited long QT syndrome is caused by mutations of at least 5 ion channel genes. Mutations of the cardiac sodium ion channel gene and 3 potassium channel genes have been identified to this time. A genetic locus on chromosome 4 has been identified, but no gene has been discovered as of yet. More than 120 mutations of the genes have been discovered. The majority of cases are inherited by autosomal dominant transmission. Syncope occurs in approximately two-thirds of gene carriers, with sudden death in 10% to 15% of untreated patients. The primary electrophysiologic disturbance is delayed recovery of the action potential, because of diverse physiologic perturbations dependent upon the specific ion channel and mutation. The delayed recovery predisposes individuals to the development of early afterdepolarizations and initiation of torsade de pointes arrhythmias. The torsade produces the syncope and sudden death. Patients with self-terminating torsade have syncope, whereas those whose torsade degenerates to ventricular fibrillation experience sudden death. The torsade maintenance appears to be because of complex reentry or repetitive triggered beats, both of which have been proposed as capable of explaining the unique and characteristic QRS morphology of torsade. It is proposed that the degree of dispersion of recovery at the time of torsade determines whether the torsade degenerates to ventricular fibrillation or self-terminates. The signs of long QT syndrome are prolongation of the QT interval on the electrocardiogram and abnormalities of T wave morphology. QTc values average 0.49 seconds and vary somewhat by genotype. Approximately 12% of long QT gene carriers have a normal QTc, < or =0. 44 seconds. Thus, a normal QTc interval does not exclude long QT syndrome. T wave morphology is relatively characteristic for each genotype. Diagnosis is likely with a QTc > or =0.48 seconds in females and > or =0.47 seconds in males. Values between 0.41 and 0.46 seconds require additional evaluation, as the disorder can neither be excluded nor made with those QTc intervals. Diagnosis is enhanced by identification of T wave abnormalities consistent with long QT syndrome. The principal treatment is beta-blocker therapy. Appropriate dosing, with ascertainment of efficacy and compliance with administration, are the key elements in therapeutic success. Molecular physiology-based strategies are being considered, including the use of sodium channel blockers in LQT3 and potassium administration in LQT1 patients.

Naturally occurring GM2 gangliosidosis in two Muntjak deer with pathological and biochemical features of human classical Tay-Sachs disease (type B GM2 gangliosidosis)

Two juvenile sibling male Muntjak deer (Muntiacus muntjak) with histories of depression, ataxia, circling and visual deficits were studied. Cerebrospinal fluid analyses revealed vacuolated macrophages that contained long parallel needle-like intracytoplasmic inclusions. Light microscopically, nerve cell bodies throughout the brain, ganglion cells within the retina and neurons in the myenteric plexuses were variably swollen and had pale granular to finely vacuolated eosinophilic cytoplasm. Neuronal cytoplasm stained specifically with sudan black and Luxolfast blue stains. Within the brain there were occasional axonal spheroids, foci of astrogliosis and scattered microglial cells with abundant pale foamy cytoplasm. Electron microscopy of the brain and retina revealed numerous neurons and ganglion cells, respectively, with multiple membrane-bound structures that contained compact electron-dense membranous whorls and fewer parallel membranous stacks. Thin layer chromatography of total lipid extracts of the cerebral cortex of both cases revealed massive accumulation of G(M2) ganglioside. Crude kidney extracts of the two affected deer were able to hydrolyze 4-methylumbelliferyl beta-GlcNAc, but not 4-methylumbelliferyl beta-GlcNAc-6-sulfate, indicating the defect of beta-hexosaminidase A. Cellogel electrophoresis of the kidney extracts also revealed the deficiency of beta-hexosaminidase A in the two deer. It is concluded that these two deer had the biochemical lesion identical to that of human type B G(M2) gangliosidosis (classical Tay-Sachs disease).

Evidence for a genetic basis for hyperandrogenemia in polycystic ovary syndrome

Our preliminary family studies have suggested that some female first-degree relatives of women with polycystic ovary syndrome (PCOS) have hyperandrogenemia per se. It was our hypothesis that this may be a genetic trait and thus could represent a phenotype suitable for linkage analysis. To investigate this hypothesis, we examined 115 sisters of 80 probands with PCOS from unrelated families. PCOS was diagnosed by the combination of elevated serum androgen levels and Collapse

Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Child
• Female
• Genetic Linkage
• Genetic Predisposition to Disease
• Humans
• Hyperandrogenism/genetics
• Middle Aged
• Polycystic Ovary Syndrome/genetics

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Grants

• M01 RR010732 NCRR NIH HHS
• MO1 RR10732 NCRR NIH HHS
• R01 DK40605 NIDDK NIH HHS
• R01 DK040605 NIDDK NIH HHS
• U54 HD034449 NICHD NIH HHS
• KO8 HD0118 NICHD NIH HHS

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Genome scan of human systemic lupus erythematosus: evidence for linkage on chromosome 1q in African-American pedigrees

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by production of autoantibodies against intracellular antigens including DNA, ribosomal P, Ro (SS-A), La (SS-B), and the spliceosome. Etiology is suspected to involve genetic and environmental factors. Evidence of genetic involvement includes: associations with HLA-DR3, HLA-DR2, Fcgamma receptors (FcgammaR) IIA and IIIA, and hereditary complement component deficiencies, as well as familial aggregation, monozygotic twin concordance >20%, lambdas > 10, purported linkage at 1q41-42, and inbred mouse strains that consistently develop lupus. We have completed a genome scan in 94 extended multiplex pedigrees by using model-based linkage analysis. Potential [log10 of the odds for linkage (lod) > 2.0] SLE loci have been identified at chromosomes 1q41, 1q23, and 11q14-23 in African-Americans; 14q11, 4p15, 11q25, 2q32, 19q13, 6q26-27, and 12p12-11 in European-Americans; and 1q23, 13q32, 20q13, and 1q31 in all pedigrees combined. An effect for the FcgammaRIIA candidate polymorphism) at 1q23 (lod = 3.37 in African-Americans) is syntenic with linkage in a murine model of lupus. Sib-pair and multipoint nonparametric analyses also support linkage (P < 0.05) at nine loci detected by using two-point lod score analysis (lod > 2.0). Our results are consistent with the presumed complexity of genetic susceptibility to SLE and illustrate racial origin is likely to influence the specific nature of these genetic effects.

Stimulation of calcitonin secretion by calcium receptor activators: evaluation using a new, highly sensitive, homologous immunoradiometric assay for rat calcitonin

Current rat calcitonin immunoassays use human calcitonin antisera, and suffer from poor sensitivity, long incubation periods, nonspecific interferences, and unreliability. The homologous immunoradiometric assay (IRMA) for rat calcitonin described here overcomes these problems. Overnight incubation yields a detection limit of 0.4 pg/mL, a standard curve that is linear to >1800 pg/mL, and intra- and interassay coefficients of variation of <7%. Gel filtration chromatography of rat plasma and rat medullary thyroid carcinoma 44-2 cell media showed that the vast majority of immunoreactivity coeluted with calcitonin standard. In 44-2 cells, increasing extracellular Ca2+ concentration or incubation with the calcimimetic compound NPS R-467 markedly increased calcitonin secretion. Plasma calcitonin levels were elevated in rats anesthetized with ketamine/xylazine and in conscious rats with chronic renal insufficiency. Calcitonin levels decreased following EGTA-induced hypocalcemia and were undetectable after thyroparathyroidectomy. In normal conscious rats, plasma calcitonin levels averaged 3-5 pg/mL and increased up to 100-fold following calcium (Ca) infusion or NPS R-467 administration. The assay also quantified calcitonin in plasma of normal and Ca-injected mice. This assay has revealed that plasma calcitonin levels in normal rats are much lower than the detection limits of most existing assays, but can increase by 100-fold on activation of the C-cell Ca2+ receptor.