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Biomedical subjects

A Benjamin

Publications and source records attributed to A Benjamin.

At least 19 recordsLinked to original sources
PubMed1997

Uveitis as the only clinical manifestation of poststreptococcal syndrome.

PURPOSE: To report a case of streptococcal infection of the upper respiratory tract in which bilateral anterior uveitis was the only complication. METHOD: Serologic documentation of post-streptococcal immune disease. The duration of inflammation was consistent with other forms of poststreptococcal immune disease. RESULTS: Bilateral anterior uveitis was treated with corticosteroids alone and resolved without ophthalmic complications. CONCLUSION: Bilateral anterior uveitis may be the only clinical manifestation of poststreptococcal syndrome.

Adolescent↗
PubMed1996

Successful pregnancy complicated by peritonitis in a 35- year old CAPD patient.

A 35-year old woman conceived six months after initiating continuous ambulatory peritoneal dialysis (CAPD). A medical plan was developed to give the patient adequate dialysis for a 1.5 g/kg/day protein intake. In addition, alterations in calcium, magnesium, and erythropoietin administration were required to reach the objectives set by the obstetrical/renal team. Three weeks prior to delivery, an amniotic leak developed, and vaginal cultures were positive for Escherichia coli. Oral amoxicillin was administered (500 mg per os q.i.d.) until the day of delivery. A 1545-g baby girl was delivered by cesarean section at 32 weeks. Five days postpartum the patient developed severe peritonitis, which subsequently grew E. coli. The patient fully recovered from the peritonitis, but catheter removal was required. Successful pregnancy can be expected on CAPD, and adequacy can be achieved with aggressive dialysis. Cesarean section delivery should probably be accompanied by full peritonitis therapy.

Administration, Oral↗
PubMed1993

Caesarean section and phaeochromocytoma resection in a patient with Von Hippel Lindau disease.

This report describes the anaesthetic management of a women with a term gestation, Von Hippel Lindau disease (VHLD), and a phaeochromocytoma, scheduled for a combined phaeochromocytoma resection and Caesarean section. Von Hippel Lindau disease is characterized by diffuse haemangioblastomas of the central nervous system (CNS) and viscera. It is also associated with phaeochromocytomas and renal cell carcinomas. Patients frequently have asymptomatic spinal cord and intracranial pathology. The patient and her fetus presented a challenge because of the anaesthetic restrictions imposed by VHLD, and her pregnancy. She was also at risk of developing malignant hypertension from the phaeochromocytoma. The patient was not a candidate for regional anaesthesia because of the possibility of spinal cord haemangioblastomas. She had received adrenergic blockade with phentolamine (total 30 mg a day) and propranolol (total 40 mg a day) since the 27th wk of gestation in order to control hypertension secondary to the phaeochromocytoma. General anaesthesia was administered with aggressive management of hypertension with adrenergic blockers (labetalol 1.0 mg.kg-1 and esmolol 0.75 mg.kg-1) and sodium nitroprusside 1.5 micrograms.kg-1 (total). Before delivery of the baby, opioids, which could have resulted in a fetus with CNS depression, were avoided. After delivery, opioids (sufentanil 0.4 microgram.kg-1 x hr-1) were used to limit the use of inhalational anaesthesia which may contribute to uterine atony. Postoperative pain was managed with an intravenous narcotic infusion. Both patients had uneventful postoperative courses.

Adrenal Gland Neoplasms↗
PubMed1993

DNA sequences and expression in Streptomyces lividans of an exoglucanase gene and an endoglucanase gene from Thermomonospora fusca.

Two genes encoding cellulases E1 and E4 from Thermomonospora fusca have been cloned in Escherichia coli, and their DNA sequences have been determined. Both genes were introduced into Streptomyces lividans, and the enzymes were purified from the culture supernatants of transformants. E1 and E4 were expressed 18- and 4-fold higher, respectively, in S. lividans than in E. coli. Thin-layer chromatography of digestion products showed that E1 digests cellotriose, cellotetraose, and cellopentaose to cellobiose and a trace of glucose. E4 is poor at degrading cellotriose and cleaves cellopentaose to cellotetraose and glucose or cellotriose and cellobiose. It readily cleaves cellotetraose to cellobiose. E1 shows 59% identity to Cellulomonas fumi CenC in a 689-amino-acid overlap, and E4 shows 80% identity to the N terminus of C. fimi CenB in a 441-amino-acid overlap; all of these proteins are members of cellulase family E. Alignment of the amino acid sequences of Clostridium thermocellum celD, E1, E4, and four other members of family E demonstrates a clear relationship between their catalytic domains, although there is as little as 25% identity between some of them. Residues in celD that have been identified by site-directed mutagenesis and chemical modification to be important for catalytic activity are conserved in all seven proteins. The catalytic domains of E1 and E4 are not similar to those of T. fusca E2 or E5, but all four enzymes share similar cellulose-binding domains and have the same 14-bp inverted repeat upstream of their initiation codons. This sequence has been identified previously as the binding site for a protein that regulates induction.

Actinomycetales↗
PubMed1993

The value of radiographs in the management of the fractured nose.

Over a 6-month period a record was kept of all patients presenting to the accident and emergency (A&E) department with nasal injuries. The results of the nasal radiographs were analysed to gauge their benefit. It was found that there was poor correlation between the radiological findings and the presence of external deformity, the latter determining the decision to carry out treatment. Routine radiographs of the nose are unnecessary in patients with nasal trauma.

Adult↗
PubMed1992

Differential expression of retinal insulin receptors in STZ-induced diabetic rats.

A major complication of diabetes mellitus is retinopathy, which is characterized by increased neovascularization and neuronal degeneration in the retina. The biochemical processes underlying these changes are largely unknown. To better understand the role(s) of insulin or its lack and the resultant hyperglycemia in the etiology of these events, peripheral and neuronal (having 125 kDa and 115 kDa alpha subunits, respectively) insulin receptor subtype levels in the retinas of Streptozocin-induced diabetic rats were quantified. Immunoblot analysis of wheat germ agglutinin-agarose purified retinal membrane proteins revealed that retinas from diabetic rats expressed higher insulin receptor levels than retinas from control rats. This increase reflected a doubling of neuronal and a approximately 20% decrease in peripheral insulin receptor subtypes, respectively. Insulin-treated diabetic rats had neuronal receptor levels equal to control values, at the same time having a further reduced number of peripheral insulin receptors relative to controls. Affinity labeling analysis of WGA-purified retinal membrane proteins indicated a 1.5-fold increase in neuronal and a 9% decrease in peripheral receptor subtypes, corroborating the immunoblot analysis. Neuronal insulin receptors in WGA-purified cortical synaptosomal membranes also were increased in diabetic rats, with insulin treatment reducing this effect. The up-regulated receptors retained their ability to undergo insulin-dependent autophosphorylation and, as such, did not appear functionally impaired. These data suggest that the expression of neuronal insulin receptors in retina and brain and peripheral insulin receptors in the retina of diabetic rats is sensitive to levels of insulin/glucose in peripheral circulation.

Adenosine Triphosphate↗
PubMed1991

Characterization of a novel receptor in toad retina with dual specificity for insulin and insulin-like growth factor I.

The biochemical properties of insulin receptors from toad retinal membranes were examined in an effort to gain insight into the role this receptor plays in the retina. Competition binding assays revealed that toad retinal membranes contained binding sites that displayed an equal affinity for insulin and insulin-like growth factor I (IGF-I). Affinity labeling of toad retinal membrane proteins with 125I-insulin resulted in the specific labeling of insulin receptor alpha-subunits of approximately 105 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of partially reduced (alpha beta-heterodimer) receptors affinity-labeled with 125I-insulin indicated the presence of a disulfide-linked beta-subunit of approximately 95 kDa. Endoglycosidase F digestion of the affinity-labeled alpha-subunits increased their mobility by reducing their apparent mass to approximately 83 kDa. This receptor was not detected by immunoblot analysis with a site-specific antipeptide antibody directed against residues 657-670 of the carboxy terminal of the human insulin receptor alpha-subunit, whereas this antibody did label insulin receptor alpha-subunits from pig, cow, rabbit, and chick retinas. In in vitro autophosphorylation assays insulin stimulated the tyrosine phosphorylation of toad retina insulin receptor beta-subunits. These data indicate that toad retinal insulin receptors have a heterotetrameric structure whose alpha-subunits are smaller than other previously reported neuronal insulin receptors. They further suggest that a single receptor may account for both the insulin and IGF-I binding activities associated with toad retinal membranes.

Animals↗
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↗