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Biomedical subjects

D Singer

Publications and source records attributed to D Singer.

At least 91 records · Page 5Linked to original sources
PubMed1983

Evidence that schistosome MHC antigens are not synthesized by the parasite but are acquired from the host as intact glycoproteins.

Schistosoma mansoni schistosomula recovered from the lungs of mice have previously been shown to express serologically detectable products of the major histocompatibility complex (MHC). To determine whether these determinants are products of the schistosome genome, DNA from cercariae and adult worms of the parasite was probed with a 32P-cDNA clone encoding a human class I MHC antigen. Although this probe hybridized to mouse DNA, no hybridization was observed with DNA isolated from schistosomes, indicating that there are no DNA sequences homologous to class I MHC antigens in the parasite genome. The class I MHC antigens found on schistosomes were characterized in a further series of experiments. Two monoclonal antibodies known to recognize spatially distinct determinants of H-2Kk both bound to lung-stage schistosomula recovered from mice expressing this haplotype, suggesting that a significant portion of the H-2K molecule is present at the larval surface. Furthermore, both antibodies precipitated from lysates of 125I-lactoperoxidase-labeled lung-stage schistosomula, a molecule of approximately 45,000 daltons similar in mobility to H-2Kk precipitated from 125I-labeled mouse spleen cells. These results support the hypothesis that the class I MHC antigens expressed on S. mansoni are not synthesized by the parasite but are acquired from the host as intact glycoproteins.

Animals↗
PubMed1983

Ultraviolet light, cataracts, and spectacle wear.

Two groups of patients older than 60 years were examined for degree of development of nuclear sclerotic cataracts. The first group of patients had worn glass spectacles for a majority of their lives, while the patients in the second group had never worn spectacles or had worn only reading glasses. Subjects in the group with spectacles showed significantly less development of sclerotic nuclear lens changes. These findings may be due to the screening effect by spectacle glass of light in the ultraviolet range and suggest that uv light may be one of the risk factors in the development of nuclear sclerotic cataracts.

Adolescent↗
PubMed1981

Ultrasonographic assessment of bladder tumors. I. Tumor detection.

A total of 37 patients with 71 bladder tumors underwent ultrasonographic examination in an attempt to evaluate its accuracy in detection of bladder tumors. Accurate detection depended on the size and location of the neoplasm. Bladder tumors less than 0.5 cm. in diameter, regardless of location, as well as those of any size located in the bladder neck or dome areas were difficult to detect. On the other hand, diagnostic accuracy was 95 per cent for tumors more than 0.5 cm. in size and situated on the posterior or lateral walls of the bladder. Thus, ultrasound is an additional diagnostic tool for detection of bladder tumors and is indicated in those cases in which cystoscopy could not be done or was not conclusive.

Cystoscopy↗
PubMed1981

Ultrasonographic assessment of bladder tumors. II. Clinical staging.

Uniformity of the echo return from the bladder wall has been demonstrated in experimental and patient studies. An infiltrating bladder tumor disrupts this uniformity. The studies also showed a sharp bladder wall outline that was less echogenic, probably representing the perivesical fat. Thus, the ultrasonographic estimation of tumor staging as related to the depth of infiltration of the bladder wall. A staging accuracy of nearly 100 per cent was found for deep tumors of the bladder wall or those penetrating extravesical structures. On the other hand, many superficial tumors were overstaged, their staging accuracy being only slightly higher than 55 per cent. However, in view of its accuracy in staging infiltrating tumors, in addition to its other already known advantages, ultrasound seems to be the method of choice in preoperative staging of tumors. We believe that it should be included in the routine protocol and should follow diagnostic cystoscopy in all cases of tumors larger than 0.5 cm.

Cystoscopy↗
PubMed1979

The effect of age on the character of immune complex disease: a comparison of the incidence and relative size of materials reactive with Clq in sera of patients with glomerulonephritis and cancer.

The impact of aging on the severity of chronic immune-complex glomerulonephritis was studied in 144 patients from whom diagnostic renal biopsies were obtained over a 3-year period. Glomerulonephritis was related to an antecedent streptococcal infection in nine of these patients. In 58, glomerulonephritis occurred in association with a systemic disease; 27 of these had lupus erythematosus. At the time of the renal biopsy, serum creatinines were more frequently abnormal in men over 40 years of age. Similarly, histological evidence of irreversible glomerular injury was more evident in men over 40. Histological indices of renal glomerular injury correlated with the presence of intense fluorescent antibody reactions specific for C3 and C4 and IgG in the glomeruli. High serum Clq binding activities (Clq BA), an indication of the presence of circulating immune complexes, also were found significantly more often in males over 40. High serum Clq BA correlated with renal functional and biopsy evidence of severe glomerulonephritis. The renal biopsies in 89 cases were tested with fluorescein-conjugated heat-aggregated IgG (FAIgG) to determine how many contained focal immunoglobulin deposits with antiglobulin activity. Antiglobulins were detected in glomeruli of 24 patients and were found significantly more often in biopsies which revealed histological evidence of severe and irreversible histological injury. Binding of FAIgG was not selectively associated with any sex or age groups. Thus, detection of circulating immune complex-like materials in sera and the presence of glomerular deposits with antiglobulin activity were both features associated with severe glomerular injury. Both correlated with the quantity of complement deposited in the glomeruli. But only serum Clq binding activity was age and sex related. Similarly, in cancer patients, abnormal Clq BA were found more frequently in sera of older men with cancer but not in age- and sex-matched controls. Examination of selected sera by sucrose density gradient ultracentrifugation revealed that the complexes from cancer patients were relatively small (less than 19S greater than 7S) whereas those in most nephritis patients were heterogeneous in size. Sera with relatively high Clq binding activity from patients with chronic glomerulonephritis tended to contain relatively greater quantities of Clq binding materials sedimenting more rapidly than 19S.

Adolescent↗
PubMed1979

Anatomic confirmation of echocardiographic measurements in neonatal hearts.

Significant correlations were demonstrated between echocardiographic measurements of left ventricular wall thickness, right ventricular wall thickness, septal thickness, left ventricular mass, aortic valve excursion, pulmonary valve excursion, mitral valve excursion, and tricuspid valve excursion and the same measurements made directly on the same hearts at autopsy. A new regression formula was derived for the calculation of echocardiographic right ventricular mass in life and was found to correlate significantly with right ventricular mass measured as the sum of right ventricular wall and septal volumes at postmortem examination.

Autopsy↗
PubMed1978

[Reproducibility of plaque formation in the dento-gingival region (3)].

Plaque formation in the lower front teeth was recorded in 12 volunteers during three periods of twelve daily visits. Special interest was paid to finding which areas always contained deposits and which were always completely free of plaques. The causative aspects of regular plaque formation were demonstrated. The predominant role of surface roughness is discussed. As a clinical consequence, testing the enamel surface with the sound is suggested for the prophylaxis of gingivitis and caries.

Adult↗
PubMed1977

[Determination of surface morphological changes during therapy of gingivitis].

Changes in inflammatory gingival disease of the anterior dental area of the mandible caused by therapy are evaluated with the help of surface morphometric methods. The clinical diversities of the healthy and diseased gum can be presented by comparative consideration of the measurements. The relationship of the contour of the gum to tartar formation and capacity for retention of plaque are interpreted. The ratio of papillary to dental surface allows these findings to be incorporated into the physiomorphological or pathomorphological state.

Adult↗
PubMed1976

[Reproductibility of plaque formation in the dento-gingival region (2)].

In 3 subjects with clinically healthy, physio-morphologic gingiva, the time factor in plaque growth was studied in 6 tests. Plaque was highly reproducible with regard to its surface dimensions and location. This holds true of both types of subject, those tending to form great amounts and those tending to form small amounts of plaque. The multi-causal process of plaque genesis is demonstrated in the tested mandibular region by the differences in plaque extent between the central and lateral incisors on the one hand and the canines on the other. The more a proband trends to form plaque, the bigger this difference is.

Adult↗
PubMed1975

Unilateral pulmonary vein atresia: Diagnosis and treatment.

The clinical, hemodynamic, angiographic and pathologic features of unilateral pulmonary vein atresia in a 16 month old boy are described. The relevant findings were symptoms and signs of influenza, roentgenographic evidence of unilateral diffuse interstitial edema, prominent interlobar fissures and pleural effusion, absence of abnormal cardiac structure and prominent unilateral bronchial circulation. Angiocardiography was necessary for a definitive diagnosis and revealed the lack of a site of entry for venous blood from the right lung into the circulation. The patient was treated successfully by a right pneumonectomy. The histologic hallmark in this case was extensive intimal fibrosis of the pulmonary veins.

Congenital Abnormalities↗
PubMed1974

Erythropoietic differentiation in colonies of cells transformed by Friend virus.

Cells transformed by Friend virus in liquid suspension culture respond to low concentrations of dimethylsulfoxide by initiating hemoglobin synthesis. The kinetics of appearance of such differentiated erythroid cells is consistent with either the induction of differentiation in a uniformly susceptible population of transformed cells or selection for the growth of a distinct erythropoietic subpopulation. The dimethylsulfoxide response of individual colonies of cells transformed by Friend virus grown in semisolid medium was studied in order to distinguish between these alternatives. The data do not support a selective effect of dimethylsulfoxide on the growth of a unique erythropoietic subpopulation; they indicate, rather, that the 745A strain of cells transformed by Friend virus consists of a relatively uniform population of dimethylsulfoxide-sensitive erythropoietic cells.

Animals↗