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Biomedical subjects

J Bernstein

Publications and source records attributed to J Bernstein.

At least 253 records · Page 14Linked to original sources
PubMed1981

Glomerular differentiation in metanephric culture.

Undifferentiated metanephric blastema, grown in transfilter culture with embryonic inductor, undergoes differentiation to nephrons, including glomeruli and tubules. As in natural nephrogenesis, mesenchymal cells aggregate and form a vesicle that elongates into an s-shaped loop; a bilaminar disc at the end of the s-shaped loop becomes the glomerulus. The glomerular tuft in culture is an arborizing structure of basement membrane covered with epithelium. The epithelial cells have foot processes separated by slit pores and bridged by slit diaphragms. The cells are coated with polyanionic material, demonstrable before the appearance of foot processes. The basement membrane of the tuft continues at a hilum with the basement membrane of Bowman's capsule. Laminae of basement membrane, lying between apposed layers of epithelium, enclose spaces that can be envisioned as vascular spaces for the ingrowth of glomerular capillaries in vivo. The glomerular structure creates, therefore, a sling for holding capillaries, as suggested by Zimmermann when he proposed the concept of the mesangium. There are, however, no blood vessels in the metanephric culture, and the glomerulus develops and differentiates without capillary ingrowth. The glomeruli lack mesangial cells and juxtaglomerular complex, suggesting that those are vascular derivatives. The development of the tuft does not depend upon invagination by sprouting blood vessels; it is inherent in the glomerular epithelium.

Animals↗
PubMed1980

Two years of mid-trimester amniocentesis in Johannesburg.

During a 2-year period 438 mid-trimester amniocenteses were performed on women at risk of producing an abnormal infant. The commonest indications were advanced maternal age (61% of cases), neural tube defects (18%) and Down syndrome (11%). A 92,5% follow-up revealed a spontaneous abortion rate of 3% (1,5% if abortions within 8 days of the procedure were considered). Premature birth occurred in 4,4% of cases, neonatal death or stillbirth in 0,7%, and birth defects which were detectable by amniocentesis in 2%. Abnormalities were detected in 4,9% of cases, so that 95,1% of the patients were reasured by the results obtained. No defects diagnosable by amniocentesis were missed.

Abortion, Incomplete↗
PubMed1980

Zinc protoporphyrin, blood lead and clinical symptoms in two occupational groups with low-level exposure to lead.

The results of cross-sectional clinical field surveys of 45 cable manufacturing workers and 90 telephone cable splicers are presented. Despite the rare occurrence of clinically overt lead poisoning among these occupational groups, high prevalence of lead-associated central nervous system symptoms and gastrointestinal symptoms was found. Hierarchical log-linear models for multidimensional contingency tables were fitted to those data and indicate that there is a partial correlation between reported symptoms and zinc protoporphyrin: individuals with high zinc protoporphyrin levels were more likely to report symptoms than those with low levels. No significant partial association was found between symptoms and blood lead. Because of the intermittent lead exposure encountered in one of the populations, individuals were identified with "normal" blood lead levels associated with "elevated" zinc protoporphyrin concentrations, thus indicating the difference in the biological significance between indicators of lead absorption (blood lead) and of biological response tests (ZPP). Suggestion is made that both types of diagnostic tests be utilized in the medical surveillance of lead-exposed workers.

Adult↗
PubMed1980

Short rib-polydactyly syndrome, type 3 with chondrocytic inclusions: report of a case and review of the literature.

A newborn with severely shortened ribs, short limbs, and postaxial polydactyly died shortly after birth. Postmortem roentgenograms established the diagnosis of type 3 short rib-polydactyly (SRP) syndrome as described by Naumoff and associates. Histopathologic study showed the chondrocytes to contain previously undescribed cytoplasmic inclusion bodies that were PAS-positive and diastase-resistant. The material appeared by staining reactions to be a glycoprotein that was seen electron microscopically to accumulate within dilated cisterns of rough endoplasmic reticulum. Similar cytoplasmic inclusions have not been seen in other short rib-polydactyly syndromes, including SRP types 1 and 2, Jeune syndrome, and Ellis-van Creveld syndrome. It is often difficult to differentiate cases of type 3 and type 1 (Saldino-Noonan) syndrome, and in the past the diagnosis has sometimes been confused. A review of previously reported cases showed that type 3 syndrome rarely (1 in 13) had cloacal developmental abnormalities, which are invariably present in patients with type 1 syndrome. Type 3 is also associated with a lower incidence of congenital heart disease, and cardiac malformations, when present, differ from those associated with type 1 syndrome. Both type 3 and type type 1 SRP syndromes are transmitted in autosomal recessive fashion. Type 3 SRP syndrome has had an equal sex distribution, although type 1 has so far been reported to occur only in girls. Further investigation with additional patients is necessary to verify the above preliminary findings.

Bone Diseases, Developmental↗
PubMed1980

Lead intoxication during development: its late effects on kidney function and blood pressure.

Exposure to lead in early life may result in chronic renal disease in adulthood. To test this hypothesis, we gave Sprague-Dawley rats, from 3 to 9 weeks of age, either tap water or a 1% lead acetate solution, and we studied them (in pairs) 3 and 16 weeks after exposure; that is, at 12 and 25 weeks of age. Lead-intoxicated animals failed to grow. Their GFR's were lower compared with the matched controls and fell between 12 and 25 weeks of age from 4.8 +/- 0.3 to 3.3 +/- 0.4 ml/min/g dry kidney wt (P less than 0.01). Changes in RBF and single nephron GFR were proportional to changes in total kidney GFR, indicating that superficial and deep nephrons were equally affected. The blood pressure in the lead-exposed animals studied at 25 weeks of age was 143.2 +/- 3.7 mm Hg, a value significantly higher than that of 130.4 +/- 3.3 observed in controls (P less than 0.05). These results demonstrate that limited exposure to lead during development can result in progressive renal insufficiency and hypertension.

Animals↗
PubMed1980

Health status of cable splicers with low-level exposure to lead: results of a clinical survey.

The results of a cross-sectional clinical field survey of 90 telephone cable splicers are presented. Despite the rare occurrence of clinically overt lead poisoning among cable splicers, the observed prevalence of symptoms was 29% for lead-associated central nervous system symptoms and 21% for gastrointestinal symptoms. These two groups of symptoms were directly related to zinc protoporphyrin (ZPP) levels but no relationship was found between them and blood lead concentrations. Only 5% of the workers had significantly elevated blood lead levels (greater than 40 microgram/100ml). Because of the intermittent lead exposure encountered in this trade, individuals were identified with "normal" blood lead levels associated with "elevated" zinc protoporphyrin concentrations, indicating the difference in biological significance between exposure-(blood lead) and biological-response tests (ZPP). Suggestion is made that both types of diagnostic tests be utilized in the medical surveillance of lead-exposured workers.

Adult↗
PubMed1980

Spondyloepiphyseal dysplasia congenita. A comparative study of chondrocytic inclusions.

Spondyloepiphyseal dysplasia congenita is a short-trunk chondrodysplasia trait. The abnormalities are present at birth and involve primarily the spine, the epiphyses of long bones, and the pelvis. Postmortem examinations of two patients with this disease who died shortly after birth showed a mild disorganization of chondrocytic columnization in the physeal growth zone. The chondrocytes contained PAS-positive cytoplasmic inclusions after diastase digestion to eliminate glycogen. Ultrastructural examination of the inclusions in one patient showed them to be accumulations of finely granular material in dilated cisterns of rough endoplasmic reticulum. To our knowledge, similar findings have been seen only in three other types of chondrodysplasia. The inclusions, which therefore are of diagnostic importance, may be of importance also in reflecting the primary metabolic abnormality.

Cartilage↗
PubMed1979

Incorporation of exogenous precursors into uridine nucleotides and ribonucleic acid. Nucleotide compartmentation in the renal cortex in vivo.

The possibility of compartmentation of UTP in vivo was investigated in the renal cortex of unanaesthetized rats. In addition, liver and spleen were studied in order to compare tissues with different utilization of precursors for pyrimidine nucleotide synthesis. After continuous 2h infusions of [(3)H]uridine or [(3)H]orotate, their incorporation into UTP, UDP-sugars and RNA was quantified. Rates of RNA synthesis were calculated by dividing the incorporation of precursor into RNA by the average specific radioactivity of the UTP pool. Although similar RNA-synthesis rates might have been expected with the two precursors, higher rates were found with uridine than with orotate. The relative incorporation into UDP-sugars of these precursors was also different. Similar results were obtained in the liver. In the spleen, equal amounts of both precursors were incorporated into UTP, but [(3)H]orotate incorporation did not lead to labelling of RNA. To evaluate the heterogeneity of cells with respect to the metabolism of pyrimidines, precursor incorporation was studied in isolated glomeruli and by radioautography. Incorporation into glomeruli was qualitatively similar to but quantitatively different from results in the renal cortex. Although there is obvious tissue heterogeneity, compartmentation of UTP pools is the most credible explanation for the results obtained with the renal cortex and liver. Consequently RNA and UDP-sugars may originate from two different UTP pools. Tissue heterogeneity is the likely explanation for the results obtained in the spleen. Studies of synthesis of pyrimidine and RNA, particularly in relation to growth and regeneration, must take into consideration the precursor used, the apparent existence of UTP compartmentation and the degree of cellular heterogeneity.

Animals↗