Biomedical subjects
Publications and source records attributed to B Singh.
A series of three cases of 'hypocalcemic dysfunction' that reflects a range of clinical profiles from a purely calcium responsive peripheral collapse to paroxysmal nocturnal dyspnea and orthopnea is reported. The underlying diversity of clinical presentation is noteworthy, as is its prompt response to calcium therapy.
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Human milk samples collected from areas having intensive cotton cultivation and sparse cotton cultivation in Punjab (India) were analysed for organochlorine insecticides. Both DDT and HCH were detected in almost all the samples analysed. The average levels of Sigma-DDT and Sigma-HCH residues in samples from cotton-growing areas were significantly higher than in those from areas where cotton is sparsely grown. Residues of Sigma-DDT mainly comprised p,p'-DDT and p,p'-DDE, while those of Sigma-HCH residues were mainly in the form of its beta-isomer. Median values of 0.52 microg g(-1) of Sigma-DDT and 0.19 microg g(-1) of Sigma-HCH in samples of human milk from cotton-growing areas of Punjab (India) were higher than those reported from most other countries in the World.
Laryngeal papillomata can undergo spontaneous malignant transformation without being detected histologically and, in some instances, the disease may become so advanced, before the diagnosis is confirmed, that it is beyond any form of curative treatment. Because of this limitation imposed by histopathological investigation, a study was undertaken in 17 adults with benign laryngeal papillomata, (three of whom underwent malignant transformation) to determine whether malignant transformation can be predicted from the clinical behaviour of the tumour. The following features were analysed: age, sex, patient's symptoms, frequency of excision of the papillomata, site of lesion, presence or absence of laryngeal oedema, the need for tracheostomy, vocal fold mobility and presence or absence of cervical lymph nodes. It was found that decreased vocal fold mobility, the presence of cervical lymph nodes, exuberant and rapid growth requiring very frequent excisions, oedema of the larynx with airway obstruction requiring a tracheostomy are clinical features suggestive of malignant transformation.
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Information about contact with psychiatric services before imprisonment was obtained for a stratified random sample of sentenced prisoners, who were not receiving prison psychiatric care, in Melbourne's three metropolitan prisons. The sample of 158 men and 31 women was matched with the longitudinal person-linked records of state psychiatric service use in the Victorian Psychiatric Case Register (VPCR). Records of contact with the state services were found for 54 men (34%) and 19 women (61%), including records of in-patient treatment for 25 men (16%) and 15 women (48%). For 64% of individuals with a positive match, the case-note diagnoses were substance use disorders only. Diagnoses of psychotic disorders were recorded for four prisoners, and mood disorders for another six. In addition, clinicians conducted standardized diagnostic interviews and enquired about treatment and personal history. A further 24 prisoners reported specialist psychiatric treatment outside the state treatment sector. This study links the findings from an interview survey of psychiatric morbidity in prisoners with the records available in the VPCR, and emphasizes a number of matters important to the public health. The high rates of previous treatment for substance abuse disorders, the apparent pool of prisoners with largely untreated major depression, and the service needs of those with chronic psychotic disorders are discussed.
The effect of very low single X-ray doses (0.05-4 Gy) was investigated in a human lung epithelial cell line (L132). Cell survival measurements were made using a Dynamic Microscopic Imaging Processing Scanner (DMIPS), which allowed single cells to be located accurately, their positions recorded and these positions revisited after an appropriate incubation period at 37 degrees C; surviving cells were identified by their ability to produce a colony > or = 50 cells. The survival data at doses > or = 2 Gy were well-fitted by a linear-quadratic (LQ) model. For doses < 1 Gy, increased X-ray effectiveness was observed with cell survival below the prediction from the fit of the LQ model to the higher dose data, extrapolated into the low dose region. This is the first evidence for the existence of a hypersensitive survival response to very low doses in normal human cells. The transition between the low dose hypersensitive region and greater resistance at higher doses, could result from induced radioresistance which requires a threshold of radiation-induced damage before being triggered.
We demonstrated that antibodies in the serum of BALB/c mice convalescent from Plasmodium yoelii infection inhibit the in vitro growth of Plasmodium falciparum. Blood stage P. falciparum antigens that cross-react with the convalescent-phase mouse serum antibodies were identified and partially characterized. Convalescent-phase mouse serum immunoglobulin G (IgG) reacted with P. falciparum lysates at up to a 1:15,000 dilution of the immune sera and bound to P. falciparum-parasitized erythrocytes at up to a 1:5,000 dilution of the sera. The cross-reactive moieties of antigens in parasite lysates were resistant to oxidation by periodate but sensitive to trypsinization. About 15 polypeptides (M(r)s of 15,000 to 110,000) of P. falciparum blood stages were recognized by the convalescent-phase mouse anti-P. yoelii sera; many of these antigens were metabolically 35S labeled and specifically immunoprecipitated. Also, virtually all of the cross-reactive antigens were recognized by human malaria-immune sera. The anti-P. yoelii serum antibodies bound, with high affinity, to at least five of the cross-reactive antigens (M(r)s of 107,000, 84,000, 53,000, 36,000, and 30,000). By phase separation in Triton X-114, eight interspecies cross-reactive antigens (M(r)s of 84,000, 76,000, 51,000, 31,000, 29,000, 28,000, 23,000, and 22,000) were found to be integral membrane proteins. Convalescent-phase mouse serum IgG strongly inhibited the differentiation of P. falciparum from schizonts to rings; 75 micrograms of IgG per ml caused 80% inhibition of release of merozoites and their invasion into erythrocytes. On the other hand, the anti-P. yoelii serum antibodies also inhibited intracellular development of P. falciparum from rings to schizonts; 25 micrograms of IgG per ml caused 50% inhibition. Inhibition of P. falciparum growth by anti-P. yoelii serum IgG suggests that some of the interspecies cross-reactive antigens contain important conserved epitopes and induce protective antibodies against P. falciparum.
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A chromosome anomaly originally detected in two intersex pigs and previously reported as a Robertsonian translocation was characterized, and its transmission pattern was assessed by analyzing the progeny and immediate relatives of a sow. Cytogenetic investigations on four phenotypically normal relatives of the intersexes, including a sow, showed that the rearrangement was a reciprocal translocation involving the X chromosome and an autosome. Giemsa-banding and reverse-banding techniques indicated that the break in the X chromosome may have occurred in the terminal segment of the short arm (Xp) and that in the autosome in the proximal segment of the acrocentric chromosome 14 (14q). Reverse-banding techniques also revealed that the normal X is the late-replicating X in female translocation carriers. Centromere banding revealed an intercalary band on the long arm of the submetacentric chromosome representing the altered X in translocation carriers. The translocation was designated as rcp (X;14) (p+;q-). Chromosome analysis on 45 of 72 live offspring of the carrier sow showed a 20:25 distribution of carriers to normal piglets, with a carrier to normal ratio of 5:13 among females and 15:12 among male piglets, indicating an overall reduction of females (18) compared with males (27). Male carriers from one litter at sexual maturity showed hypoplastic testes and no spermatozoa in their ejaculates or fluid aspirates from the cauda epididymis. Their seminiferous tubules were narrow, spermatogenesis was impaired, and pyknotic and giant nuclei were abundant in the germinal epithelium. Meiotic preparations showed no stage beyond pachytene, suggesting that the absence of spermatozoa in the ejaculates may be due to the arrest of cells at the pachytene stage.
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Kaposi's sarcoma is the most common neoplastic process in patients infected with the human immunodeficiency virus. Moreover, the occurrence of Kaposi's sarcoma in human immunodeficiency virus-infected patients advances their classification to having the acquired immunodeficiency syndrome. We reviewed the medical records of 48 patients with human immunodeficiency virus infection who had Kaposi's sarcoma documented on their initial visit to the hospital. The onset of Kaposi's sarcoma occurred independent of the Centers for Disease Control and Prevention classification of human immunodeficiency virus infection (modified to exclude Kaposi's sarcoma). This neoplasm developed more frequently in patients who acquired human immunodeficiency virus infection by sexual contact (75% of cases), but manifestations were not significantly different in any of the risk populations for human immunodeficiency virus infection. Kaposi's sarcoma lesions were unpredictable and either showed progression, remained static, or occasionally, regressed spontaneously. Moreover, the lesions were usually multifocal at presentation, with the head and neck (62.5% of cases) as the primary site of involvement. In this region cutaneous lesions predominated (66.7%), followed by mucosal (56.7%) and deep structure (13.3%) involvement. The majority of patients with acquired immunodeficiency syndrome Kaposi's sarcoma involving head and neck structures were asymptomatic (80% of cases). Mucosal lesions were associated with symptoms in 29.3% of cases, whereas cutaneous lesions had symptoms in 5% of cases.
We report two children with hemisomatic spasms caused by neoplastic lesions in the region of the ipsilateral cerebellopontine angle. In this condition, seizure misdiagnoses are frequent and EEGs are normal, even ictally. MRI should be performed early to prevent delay of appropriate treatment.
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The 65-kDa isoform of glutamic acid decarboxylase (GAD65) has been implicated in autoimmune diabetes in NOD mice, but the role of the 67-kDa GAD isoform (GAD67) is less clear. We found that immunization of 4-week-old NOD mice with purified recombinant mouse GAD67 prevented or significantly delayed the onset of diabetes. To further explore this phenomenon, we characterized anti-GAD67 immune responses in naive and GAD-immunized NOD mice. Anti-GAD67 antibodies titers were relatively low in naive mice at all ages, but a single immunization with GAD67 at 4 weeks induced high titers of anti-GAD antibodies by 6 weeks of age. In both 4-week-old and diabetic NOD mice, there were significant endogenous T-cell proliferative responses against purified recombinant mouse GAD67. These T-cell proliferative responses were blocked by anti-I-ANOD and anti-CD4 antibodies. To characterize the anti-GAD T-cell responses in the NOD mice, we established T-cell lines and T-cell clones which recognized GAD67, and we used recombinant subfragments of GAD to localize the predominant T-cell epitopes in GAD67. T-cells from naive NOD mice proliferated in response to all GAD subfragments, whereas T-cells from diabetic mice responded primarily to the COOH-terminal 83 amino acids of GAD67. These results suggest that GAD67 is an autoantigen in IDDM and immunization of prediabetic NOD mice with GAD67 can prevent the onset of diabetes.
A review of 12 cases of bony tumors involving the talus is presented. Giant cell tumor was the most common tumor. Malignant tumors should be treated by surgical ablation followed by chemotherapy. There are good results after excision or curettage and bone grafting in the treatment of benign neoplasms. Giant cell tumors, if diagnosed early, can be treated by curettage and bone grafting, but if there is talar collapse, a talectomy can be performed.
OBJECTIVE: To determine whether immunization of HLA-B27 transgenic mice with a peptide containing the crossreactive QTDRED sequence found in B2705 and Klebsiella nitrogenase induces a detectable immune response. METHODS: Mice were immunized with a synthesized peptide corresponding to the 65-84 region of HLA-B2705 in Freund's complete adjuvant (FCA). Mice were bled for antibody assays 10 days after the last injection. Popliteal lymph node cells for T cell proliferation assays were obtained 10 days after foot pad inoculation. RESULTS: The healthy control mice responded well to the peptide in both humoral and cellular assays. The transgenic mice carrying HLA-B2705 did not, although they did respond as expected to the FCA. CONCLUSION: Our data suggest that the homologous epitopes present in HLA-B2705 and Klebsiella do not induce a crossreactive immune response in animals naturally tolerant to the HLA antigen.