Differential diagnostic utilities of combined testing for islet cell antibody, glutamic acid decarboxylase antibody, and tyrosine phosphatase antibody

Background. Beta-cell antibody tests are used for the differential diagnosis of diabetes mellitus. They permit to discriminate between the type 1 diabetes (T1D) and non-autoimmune diabetes types. To choose an appropriate test for ruling in or ruling out the T1D a physician needs to know how conclusive test results are. The most powerful estimate of test conclusiveness is its likelihood ratio (LHR). The higher LHR of a positive result (LHR+), the more posttest probability of T1D; the lower LHR of a negative result (LHR), the less posttest probability of T1D. Aims. To compare conclusiveness of single and combined tests for antibodies to islet cells (ICA), glutamate decarboxylase (GADA), and tyrosine phosphatase IA-2 (IA-2A), and to evaluate posttest probabilities of T1D at various pretest probabilities. Methods. All antibodies were tested in parallel in 169 children and adolescents with a new-onset T1D, and in 169 persons without this disease. ICA, GADA, and IA-2A were determined by indirect immunofluorescence, radioimmune assay, and ELISA, respectively. LHR+ and LHR were calculated with the MedCalc Statistical Software. Posttest T1D probabilities were calculated from Bayes theorem-based equation. Results. Among single tests, an ICA test had the greatest LHR+ and the smallest LHR, and consequently was the most reliable either for ruling in or ruling out the T1D. Among test combinations, an ICAGADA combination had the greatest LHR+ and was the most suitable for T1D confirmation. The triple combination ICAGADAIA-2A had the smallest LHR and was the most suitable for T1D exclusion. Conclusions. In the differential diagnosis of diabetes, the most appropriate test for ruling in the T1D is the double combination ICAGADA. With both antibodies positive, this combination provides the highest posttest T1D probabilities at any pretest probability. The most appropriate test for ruling out the T1D is the triple combination ICAGADAIA-2A. With all three antibodies negative, this combination provides the lowest posttest T1D probabilities.

Melatonin Levels in Serum and Ascitic Fluid of Patients with Hepatic Encephalopathy

Cirrhotic patients exhibit disturbed melatonin homeostasis, which may lead to sleep disturbances, but an influence on the hepatic encephalopathy has not been elucidated.Aim. In the present study, the association of melatonin levels in serum and ascitic fluid and ammonia concentration related to the intensity of hepatic encephalopathy (HE) was investigated.Material and Methods. The study included 90 alcoholic patients with hepatic encephalopathy and 30 healthy volunteers (C). Patients were divided in three groups according to 0–4 West-Haven Score: HE1(n=28), HE2(n=30), and HE3(n=32). Melatonin was measured by radioimmune assay.Results. In fasting patients with hepatic encephalopathy we noted higher melatonin serum levels [pg/mL] than in healthy subjects groups: C—11.3 ± 3.9, HE1– 34.3 ± 12.2(P<0.01), HE2—54.8 ± 23.9, and HE3—119.8 ± 96.4(P<0.001). No correlation between melatonin and ammonia levels was found. Melatonin was detected in ascetic fluid in 24 patients of group HE2and 27 patients of group HE2of hepatic encephalopathy.Conclusions. Our results suggest that high blood levels of melatonin in cirrhotic liver patients may account for some of the clinical manifestations of hepatic encephalopathy, for example, daytime sleepiness, fatigue.

Physics in Medical Science

The domain of Physics covers vast area of scientific knowledge. Basic research on assemblies of atomic or nuclear radiation and gyromagnetic moments led to powerful technique for studying molecular structure as well as solid lattices. It led to invention and development of modern medical diagnostic and theraputic tools which have revolutionized the medical practices. Advancement in medical researches as seen today will be well-nigh impossible without the use of the finding of Physics. The funding made on Physics is in fact another way of funding made on human health.Keywords: Radioactivity; Crystallography; Radioimmune assay; MRI; CAT; PETThe Himalayan PhysicsVol.2, No.2, May, 2011Page: 43-46Uploaded Date: 1 August, 2011

Urine Drug Screening

Illicit substance use among children and adolescents is a major health concern in our society. Increasingly, pediatricians are confronted by parents requesting that their children be tested for illicit drugs. Pediatricians and other practitioners, therefore, should be knowledgeable about drug testing techniques and understand how to interpret the results. Likewise, the legal and ethical issues surrounding drug testing should be evaluated thoroughly. The four urine drug screening tests used most commonly are: radioimmune assay (RIA), enzyme-multiplied immunoassay test (EMIT), fluorescent polarization immunoassay (FPIA), and latex agglutination test (ONTRAK). According to Schwartz, these newer, more sensitive immunoassay tests essentially have replaced the older, conventional thin-layer chromatography methodology, which required larger sample sizes and longer turn-around times.

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This investigation presents the results of Hepatitis B virus screening among leprosy patients conducted in Central Brazil as a preliminary information for a HBV vaccination programme. The main objectives were to assess the seroprevalence of HBV serum markers among lepromatous patients and to analyse institutionalization as risk factor for HBV infection in this population. Two groups of lepromatous patients were studied, 83 outpatients and 171 institutionalized ones. Screening for HBV serum markers included the detection of HBsAg, anti-HBc by radioimmune assay (RIA). The prevalence of carrier state (HBsAg) was 4.8% and 8.8% among outpatients and institutionalized, respectively, (p>0.05). Seroprevalence of exposure (all markers) was statistically significant different between outpatients (16.9%) and institutionalized ones (50.3%). Institutionalized patients had an almost four fold risk of HBV infection when compared to the outpatients, and the highest risks were among patients with more than 21 years of residence in the colony, after adjusting for age and sex.

Receptor patching and capping of platelet membranes induced by monoclonal antibodies

Redistribution of glycoproteins (GP) Ib, glycocalicin, IIb, and IIIa on the surface of human platelets in response to stimulation with corresponding monoclonal antibodies (MoAb) and a polyclonal antiglycocalicin antibody was studied by immunofluorescence, immunoelectron microscopy, and a quantitative radioimmune assay. Immobilization of the antigens by prefixation with formaldehyde showed a uniform distribution over the surface of the platelet. Incubation of unfixed platelets with specific MoAb against various epitopes on GPIIb and/or IIIa resulted in a time-dependent patching, subsequent capping, and after prolonged exposure to the antibody/label complex, internalization of the complex, possibly by endocytosis. In contrast, GPIb could not be shown to cap. From these results we conclude that platelet GPIIb and/or IIIa undergo spatial rearrangement in a manner analogous to that observed in lymphocytes, whereas GPIb does not. Since both GPIb and GPIIb and/or IIIa seem to be transmembraneous GP associated with the cytoskeleton, a special, though unidentified, role of GPIIb/IIIa in the induction of lateral membrane mobility is postulated.

Receptor patching and capping of platelet membranes induced by monoclonal antibodies

Redistribution of glycoproteins (GP) Ib, glycocalicin, IIb, and IIIa on the surface of human platelets in response to stimulation with corresponding monoclonal antibodies (MoAb) and a polyclonal antiglycocalicin antibody was studied by immunofluorescence, immunoelectron microscopy, and a quantitative radioimmune assay. Immobilization of the antigens by prefixation with formaldehyde showed a uniform distribution over the surface of the platelet. Incubation of unfixed platelets with specific MoAb against various epitopes on GPIIb and/or IIIa resulted in a time-dependent patching, subsequent capping, and after prolonged exposure to the antibody/label complex, internalization of the complex, possibly by endocytosis. In contrast, GPIb could not be shown to cap. From these results we conclude that platelet GPIIb and/or IIIa undergo spatial rearrangement in a manner analogous to that observed in lymphocytes, whereas GPIb does not. Since both GPIb and GPIIb and/or IIIa seem to be transmembraneous GP associated with the cytoskeleton, a special, though unidentified, role of GPIIb/IIIa in the induction of lateral membrane mobility is postulated.