Biomedical subjects
D Rubenstein
Publications and source records attributed to D Rubenstein.
A new doubly substituted sickling haemoglobin: HbS-Oman.
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Meningitis after BCG vaccination.
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Mother-daughter in vitro fertilization triplet surrogate pregnancy.
A successful triplet pregnancy has been established in a surrogate gestational mother following the transfer of five embryos fertilized in vitro. The oocytes were donated by her biological daughter, and the sperm obtained from the daughter's husband. The daughter's infertility followed a total abdominal hysterectomy performed for a postpartum hemorrhage as a result of a placenta accreta. Synchronization of both their menstrual cycles was obtained using oral contraceptive suppression for 2 months, followed by stimulation of both the surrogate gestational mother and her daughter such that embryo transfer would occur at least 48 hr after the surrogate gestational mother's own ovulation. This case raises a number of medical, social, psychological, and ethical issues.
The Segond fracture of the proximal tibia: a small avulsion that reflects major ligamentous damage.
The Segond fracture is a small vertical avulsion injury of the lateral aspect of the proximal tibia just distal to the plateau. It results from excessive internal rotation and varus stress. The plain film and arthrographic findings were studied in nine patients with the fracture. Although previous publications have relied primarily on the anteroposterior projection for diagnosis, the injury was apparent only on the tunnel view in two of our cases. The arthrogram was particularly important in identifying abnormalities of the anterior cruciate ligament (nine of nine cases) and/or meniscal tears (six of nine cases). The arthrographic findings related to the lateral ligamentous damage depended on the severity of the injury and on the interval between the injury and the arthrogram. In our series, the Segond fracture was uniformly associated with detachment of the capsular portion of the lateral collateral ligament and tears of the anterior cruciate ligament. In the majority of cases, there were associated injuries of the menisci and other supporting ligaments.
Multiple cutaneous granular cell tumors in children.
Multiple cutaneous granular cell tumors are rare in childhood. We cared for two children with 15 and 6 tumors respectively. The tumors were asymptomatic nodules in the skin. Histologically, they consisted of large cells containing granules that were positive on periodic acid-Schiff stain and diastase resistant.
Cost-benefit evaluation of body computed tomography.
Cambridge Health Authority accepted the gift of a whole body computed tomography (CT) scanner and radiotherapy planning system for Addenbrooke's Hospital (AH) from a local charity in 1981. The charity was to provide funds for the maintenance and all running costs for the first 5 years. Acceptance of the gift was conditional on an evaluation of the use of body CT before any decision about subsequent funding was made. The results of this evaluation are presented here. A detailed assessment fo 150 consecutive CT studies was performed together with an audit of CT use. The costs of running the CT unit and an indirect measurement of the benefits brought about by body CT were evaluated. In 86% of patients the CT findings were considered likely to have a great contribution to clinical management; in less than 10% was little or no benefit likely. In most patients (68%) CT was considered to have been more useful than any alternative test(s) would have been. The total cost of CT during the financial year 1983-84 was 219,163 pounds and the average cost per CT study was 73 pounds. The assessment indicated annual benefits fo 673,385 pounds including the saving of 3,880 inpatient bed days, 760 outpatient visits and alternative tests costing 290,684 pounds p.a. Some corroborative evidence that these benefits have occurred is presented. This study suggests a cost benefit ratio of 1:3.07.
Effects of tumor promoters on sodium ion transport across frog skin.
Phorbol esters are tumor promoters and mitogens whose effects may be mediated by changes in ion transport across membranes. Clarification of the transport effects of these agents should be facilitated by using a well-characterized model epithelial system whose intracellular and transmural parameters are readily measurable. The current results constitute a preliminary study of the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA), phorbol-12,13-dibutyrate (PDBU), and phorbol on the short-circuit current (Isc) across frog skin. TPA produced two effects: a stimulation of Isc of variable magnitude and a far more constant inhibition of the natriferic action of vasopressin. These effects appear related to the action of TPA as a tumor promoter insofar as PDBU (an active ester) also inhibited the natriferic response to vasopressin, whereas phorbol (inactive as a tumor promoter) had no significant effect. TPA is largely active from the mucosal medium, inhibits the natriferic response to adenosine 3',5'-cyclic monophosphate (cAMP) as well as that to vasopressin, and does not stimulate Isc in the presence of 10(-4) M mucosal amiloride. Inhibition of prostaglandin E1 production by indomethacin had no effect on the actions of TPA. The results indicate that frog skin is a promising model for studying the transport effects of the phorbol esters. The data further suggest that TPA acts on frog skin by activating the physiological amiloride- and cAMP-sensitive channels gating apical Na+ entry from the mucosal medium into the epithelial cells.
Zinc deficiency during parenteral hyperalimentation.
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Bacillus thuringiensis var israelensis: protoxin activation and safety.
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Visceral leishmaniasis: a rare imported disease.
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The older person in prison.
Through an extensive review of the literature a profile of the older prisoner is described. Psychologically, the elderly inmate is insecure, fearful, and becomes 'sedated' (giving up). Sociologically, the process of prisonization is examined and the concept of institutional neurosis occasionally appears and is manifested in older prisoners not wanting to leave prison. The elderly are also associated with social control as persons not likely to riot and serving as a stabilizing force. The issues of age-integrated versus age-segregated environments are discussed with alternative living patterns suggested. The research methodology in criminal justice studies are critiqued and recommendations are made for more effective study.
Upper gastrointestinal barium studies in the elderly: follow-up in 101 patients.
A A retrospective study of 101 elderly patients who were referred for upper gastrointestinal barium studies showed that this led to a change of management in 36 patients. The commonest management change was endoscopic referral (10 patients). However, in only on patient did this sequence lead to surgery and this was merely palliative. Dysphagia, vomiting and weight loss were shown to be the presenting features most likely to result in an abnormal barium study. The most frequently detected abnormalities were hiatus hernia, reflux, oesophageal stricture, peptic ulcer and gastric carcinoma.
Screening investigations in the elderly.
The study evaluates the usefulness of some commonly used screening investigations in the management of elderly acutely ill medical patients. It was performed on 50 consecutive admissions to one ward and all patients received a full blood count, ESR, urea and electrolyte estimation, liver function tests, thyroid function tests, examination of a mid-stream urine specimen and P-A chest X-ray examination. When performed in the absence of clinical indication these tests were considered to be screening tests. On assessing the tests performed prospectively, it was shown that only a full blood count, urea and electrolyte estimation, ward testing of urine, and, possibly, a P-A chest X-ray examination are worthwhile screening investigations in this patient population. The ESR and liver function tests and mid-stream urine specimens seem to be of little value in the absence of clinical indication.
Pressure-induced deformation in immature airways.
The effect of positive pressure ventilation on the highly compliant fetal airways was evaluated utilizing fetal rabbit tracheal segments. The degree of mechanical and dimensional deformation was quantified to the pressure applied intermittently (IPP) or continuously (CPAP) for 60 min. Excised tracheal segments were obtained at 21, 27, and 31 days fetal rabbit gestation (term = 31 days) and from 18 +/- 6-month-old adults. Internal diameter, resting length, and volume of the tracheal segments were measured, and their pressure-volume relationships were determined by plethysmography. Tracheal specific compliance at deflation pressure of 0 to 10 cm H2O was calculated from these data. In all fetal groups, the application of positive pressure resulted in a decrease of both tracheal distensibility and the slope of the pressure-volume curves; in addition, a highly significant decrease in tracheal specific compliance was documented. At 21 days gestation, the tracheal specific compliance decreased from 0.089 to 0.034 cm H20-1 (P less than 0.001) after CPAP and to 0.025 cm H2O (P less than 0.001) after IPP. For the same group, the resting tracheal volume increased by a dramatic 89% (P less than 0.001) after CPAP and by 124% (P less than 0.001) after IPP. The magnitude of these alterations decreased as gestational age advanced; the changes were not significant by adulthood. These data indicate that significant pressure-induced deformation (barotrauma) is sustained by susceptible immature airways.
Secretion of cholesterol-rich lipoproteins by perfused livers of hypercholesterolemic rats.
Rats maintained on a high-fat diet supplemented with propylthiouracil develop a hypercholesterolemia, an increased serum level of apolipoprotein (apo) E, abnormal very low density lipoproteins (VLDL) and low density lipoproteins (LDL), and a fatty liver which contains cholesterol ester as its major lipid. The fatty liver secretes apoE into a recirculating perfusate at a significantly higher rate and produces cholesterol ester-rich, apoC-deficient VLDL with slower electrophoretic mobility than the triacylglycerol-rich VLDL produced by perfused normal livers. LDL, secreted in significant quantities by the perfused fatty liver, but not by the normal liver, is also cholesterol rich and contains apoE as well as apoB. The incorporation of [(3)H]leucine into apoVLDL and apoLDL secreted by the livers of the hypercholesterolemic animals and the apoVLDL secreted by the normal liver corresponds to the pattern visualized when the apoproteins are separated by polyacrylamide gel electrophoresis. Similar patterns are noted when non-recirculating perfusates are studied. These results indicate that the cholesterol ester-rich, apoC-deficient VLDL and the apoE-containing LDL found in the serum of hypercholesterolemic rats are not solely catabolic remnants of VLDL and chylomicrons but are secreted by the liver. Separation of the perfusate lipoproteins by agarose gel filtration revealed that most of the apoE secreted by the livers of hypercholesterolemic rats is found in the VLDL and LDL, whereas apoE secreted by the normal livers is distributed equally between VLDL, high density lipoproteins, and a low molecular weight fraction which corresponds to the virtually delipidated apoprotein. Thus the distribution of apoE among the lipoprotein fractions may be related to the total amount of cholesterol being transported in the circulation.
Initial splanchnic extraction of ingested glucose in normal man.
Estimates of initial splanchnic uptake of ingested glucose and the concomitant suppression of endogenous glucose production were obtained in man by validated tracer techniques for non--steady-state turnover measurement. Nine normal volunteers (18--44 yr old) fasted overnight received intravenous infusions of tracer (3-3H-glucose or 1-14C-glucose) and a low (45 +/- 1 g) or high (96 +/- 5 g) oral load of glucose labeled with an alternative tracer (1-14C-glucose or 2-2H-glucose). A two-compartment model was used to derive rates of peripheral appearance (Ra) of glucose from all sources (total) and the Ra of ingested glucose. Ra (total glucose) and Ra (ingested glucose) were integrated from the first appearance of ingested glucose until the basal Ra (total glucose) or 116 +/- 6 (SEM) mg/min was reattained. The total amount of glucose reaching the systemic pool in this time was 95 +/- 4 g and 46 +/- 3 g with high and low doses, respectively. Of these quantities 86 +/- 4 g and 40 +/- 3 g originated in the oral glucose, representing 90% +/- 4% of the administered glucose. The remainder (11% +/- 2% of the total) represented endogenous production, suppressed by 66% +/- 6% relative to basal. Sequestration of ingested glucose and subsequent release did not take place during the study since identical results were obtained with ingested 1-14C-glucose or 2-3H-glucose. The latter label would have been lost if the glucose had entered the hexose--phosphate pool. Thus, in normal man approximately 90% of an ingested glucose load is absorbed and passes through the liver to appear in the systemic pool.