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Biomedical subjects

A Benjamin

Publications and source records attributed to A Benjamin.

At least 37 records · Page 2Linked to original sources
PubMed1990

Identification of retinal insulin receptors using site-specific antibodies to a carboxyl-terminal peptide of the human insulin receptor alpha-subunit. Up-regulation of neuronal insulin receptors in diabetes.

Insulin receptor-specific polyclonal antipeptide serum was generated against a synthetic pentadecapeptide (residues 657-670) of the deduced amino acid sequence of human insulin proreceptor cDNA for use in the analysis of insulin receptors in the retina. The affinity-purified antibodies recognized peptide antigen but not keyhole limpet hemocyanin as determined by dot blot analysis and solid phase radioimmunoassay. Addition of either synthetic peptide or the affinity-purified serum had no effect on 125I-insulin binding to placental membranes or to cells in culture. alpha-Subunits of approximately 125 kDa from human placental membranes and liver membranes were labeled by immunoblot analysis with this antiserum. In membranes isolated from human retina and brain, two classes of alpha-subunits of approximately 125 and 115 kDa were detectable. The 115-kDa subunit was neuraminidase resistant whereas the 125-kDa subunit was digested to a band of 115 kDa, indicating that these bands represent peripheral and neuronal receptors, respectively. Analysis of human retinas obtained from type I diabetic donors revealed an increased level of neuronal receptor as compared with normal retinas. These data indicate that human retina expresses neuronal insulin receptor subtypes that are up-regulated in diabetes.

Amino Acid Sequence↗
PubMed1988

Does the maternal kidney contribute to the increased circulating 1,25-dihydroxyvitamin D concentrations during pregnancy?

The observation that during pregnancy the circulating 1,25-dihydroxyvitamin D, 1,25(OH)2D, concentrations are higher than in the nonpregnant state as well as recent evidence showing that, in vitro, the placenta and/or decidua are sites of 1,25(OH)2D synthesis has led to the general belief that the increased circulating 1,25(OH)2D concentrations originate from the placenta and/or decidua during pregnancy. The observation of a patient with end-stage renal disease who became pregnant after 10 years of chronic hemodialysis treatment has revealed that, despite delivery of a viable infant who had a normal development for gestational age and of normal serum 25-hydroxyvitamin D levels, her serum 1,25(OH)2D3 concentrations were only 10-15 pg/ml following 25 weeks of gestation. These 1,25(OH)2D3 concentrations are far lower than those usually encountered in normal women at the end of the 2nd trimester of pregnancy. It is felt that an important contribution of the placenta and/or of the decidua to the synthesis of the hormone should have led to higher 1,25(OH)2D3 concentrations than those observed in this patient. These observations, along with evidence from the literature, prompted us to reappraise the hypothesis on the origin of the circulating maternal 1,25(OH)2D3 during pregnancy and to postulate that the kidney might be more important than previously thought to the synthesis of the hormone during pregnancy.

Alkaline Phosphatase↗
PubMed1987

Invasive monitoring and anaesthetic management of a parturient with mitral stenosis.

The anaesthetic management of a parturient with mitral stenosis is presented and discussed. In particular, the beneficial effects of epidural anaesthesia for vaginal delivery are described with respect to the significant improvement noted in haemodynamic parameters. The information derived from the pulmonary artery catheter greatly assisted the management of the patient throughout labour and in the puerperium.

Adult↗
PubMed1986

Has use of cesarean section reduced the risks of delivery in the preterm breech presentation?

The effect of cesarean section on the condition at birth in cases of preterm breech presentation was studied in consecutively delivered infants in two time periods. Delivery was rarely (8%) by cesarean section in 1961 to 1974 and usually (89%) by cesarean section in 1978 to 1984. The increased cesarean rate did not reduce the incidence of severe depression, which was double that in control cases with cephalic presentations in both periods. Breech births did not have a higher mortality rate than cephalic births in either period; birth trauma and encephalopathy were similar in both periods. Cesarean section was therefore not found to reduce either the incidence of depression at birth or the mortality. However, head entrapment was responsible for the deaths of seven of 55 live-born infants delivered vaginally at 25 to 28 weeks' gestation, all weighing less than 1000 gm. Although cesarean section is at present performed least often among these extremely premature infants, it is in these cases that it may prove most beneficial.

Asphyxia Neonatorum↗
PubMed1984

Instability of the ankle due to a separate centre of ossification in the lateral malleolus.

A case of recurrent instability of the ankle is reported. It was associated with a separate centre of ossification in the lateral malleolus. While such extra ossification centres for both malleoli are recognized, they have not hitherto been incriminated as a cause of instability. The successful treatment of this case is described and the incidence and significance of separate ossification centres for the malleoli are discussed.

Adolescent↗
PubMed1983

The place of osteotomy in rheumatoid arthritis.

Osteotomy is technically simple without the incidence of serious complications of prosthetic joint replacement. It relieves pain in the majority of patients in whom it is indicated. Following osteotomy the range of joint movement is only increased in so far as muscle spasm is relieved by freedom from pain. Deformities and soft tissue imbalance can be corrected. Hypertrophic rheumatoid synovium regresses dramatically and rapidly after double osteotomy even if the joint is not opened. In those patients in whom pain is relieved, function improves, strength increases and the radiographic changes of disuse reverse with improved bony structure.

Aged↗
PubMed1982

The role of cell age in the difference in insulin binding between adult and cord erythrocytes.

Erythrocytes (RBCs) from cord blood are known to bind more insulin than those of adults. We have investigated the possibility that this difference is due to the younger cell age of the neonatal cells. Samples from 13 normal full term neonates and 12 adults were fractionated into 5 fractions of defined density by dextran gradient centrifugation. Fractions of comparable density, a variable known to correlate well with age, were then compared for insulin binding. Plasma insulin and glucose levels were the same in the two study groups. The density distribution curve was shifted to the left for the cord samples, indicating a younger cell age. The difference was most marked in the lightest fraction, which contained 4.66 + 0.46% (mean +/- SE) adult cells vs. 15.26 +/- 1.27% cord cells (P less than 0.01). Insulin binding was identical when fractions of equal density were compared in the two groups. The only exception was the lightest (youngest) fraction (density, less than 1.092), in which the cord cells displayed a considerably higher percentage of specific binding; (19.98 +/- 1.57 vs. 13.32 +/- 0.92 P less than 0.005). This difference was shown to be due to a high percentage of very light cells in cord samples, compared to adult samples, in this fraction which, unlike the others, did not have a lower limit of density. When a lower density cutoff was introduced (1.089 g/ml), the remaining cells of this fraction (density, 1.089-1.092) displayed quite similar percentages of specific binding (13.07 +/- 1.63 vs. 11.86 +/- 1.27). Cells below this density were virtually absent in the adult, comprising less than 0.3% of all adult cells compared to 7.2% of the cord cells. These results indicate that the difference in insulin binding between adult and cord cells is due to a younger RBC age distribution in cord blood. This difference is most marked in the youngest cell fractions. Age fractionation of RBCs by density gradient centrifugation appears to be a promising method of assessing RBC insulin receptors in situations in which substantial changes in cell age are seen.

Adult↗
PubMed1979

The treatment of arthritis of the shoulder joint by double osteotomy.

This paper presents the new operations of double osteotomy of the shoulder for the treatment of painful arthritis. The procedure consists of osteotomy without displacement of the necks of both the scapula and the humerus. Sixteen patients who have had this operation have been followed for one to nine years (average 2 years 11 months). The results show good or excellent pain relief in 13 patients and a substantial increase in active abduction in 13 patients. Complications were few and none were serious. A possible reason for the reduction of pain is suggested and the advantages of this operation over arthrodesis and total shoulder replacement are discussed.

Adult↗
PubMed1975

Orthopedic applications of liquid crystal thermography.

Liquid crystal thermography can assist the clinician in evaluating inflammatory conditions or delineating viability of tissues by the differences in coloration that occur with the use of these unique substances. The technique has proved useful in studying hemophilia, tumors of the extremities, arthritis and vascular conditions, including the complications of diabetes.

Arthritis↗