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Biomedical subjects

B E Cohen

Publications and source records attributed to B E Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1985

Malignant phenylketonuria due to defective synthesis of dihydrobiopterin.

A defect in the synthesis of dihydrobiopterin was detected in an Arab girl, ascertained through high blood phenylalanine level on neonatal screening. An oral loading test with tetrahydrobiopterin (BH4) caused a significant fall in her blood phenylalanine and a rise in tyrosine concentrations. Her blood biopterin levels were low. In urine and cerebrospinal fluid (CSF) very high neopterin and low biopterin levels were observed. A deficiency of metabolites of neurotransmitters, serotonin and dopamine, was observed in CSF and urine. The patient was given replacement therapy of BH4, 5-hydroxytryptophan, and L-dopa with carbidopa starting from the age of 16 to 18 weeks. On this treatment the blood phenylalanine levels dropped to the desired range, while in urine and CSF a satisfactory rise of neurotransmitter metabolites was observed. In spite of this biochemical control, the patient developed neurological symptoms with myoclonic jerks and changes in muscle tone and presented severe cerebral damage with mental retardation. She died suddenly at the age of 38 weeks.

5-Hydroxytryptophan↗
PubMed1984

Shoulder defect correction with the island latissimus dorsi flap.

Reconstruction of normal shoulder contour is possible utilizing a latissimus dorsi musculocutaneous flap at the end of a long neurovascular pedicle. The thoracodorsal vessels and their lateral divisions form the basis of the pedicle. The nerve in the pedicle is left intact if maintenance of muscle bulk is desired and sectioned if atrophy is preferred. The amount of muscle taken in conjunction with the skin island is determined by the nature of the defect to be corrected. The twin goals of a single-stage reconstruction and a satisfactory aesthetic result are achieved with this method.

Adult↗
PubMed1984

IgE induces secretion of prostaglandin E2 by human monocytes.

IgE was isolated from a patient with the hyper IgE, recurrent infection syndrome by immunoadsorption on sepharose bound goat anti-human IgE. Addition of this IgE to a monolayer culture of human monocytes resulted in a dose-dependent increase in PGE2 secretion. The addition of F(ab')2 fraction of goat anti-human IgE in the presence of sub-stimulating doses of IgE markedly increased PGE2 secretion; whereas addition of F(ab')2 fragment of irrelevant goat IgG had no effect. Similar activation of monocytes which could be enhanced by anti IgE was observed in the presence of the patient's serum. No such effect was seen in the presence of normal human serum. These results indicate that IgE may activate human monocytes and induce PGE secretion.

Adolescent↗
PubMed1984

Effects of pH and temperature on the stability and decomposition of N,N'N"-triethylenethiophosphoramide in urine and buffer.

N,N',N"-Triethylenethiophosphoramide (thiotepa) was dissolved at 100 micrograms/ml in urine or in 0.1 M sodium acetate buffer and incubated at 37 degrees or 22 degrees. After 0, 15, 30, 60, 90, and 120 min of incubation, 0.1-ml samples were extracted into ethyl acetate and analyzed by gas-liquid chromatography (1.8-m X 2-mm column packed with 3% OV225 on 100/120 Supelcoport; oven at 180 degrees; injection port and nitrogen-phosphorus detector at 230 degrees). Thiotepa was more stable at 22 degrees than at 37 degrees and at pH 6 to 7 than at pH 4 to 5.5. After 2 hr of incubation at 37 degrees, thiotepa concentrations decreased by 40% at pH 5.0 but only 10% at pH 6 or 7. Although thiotepa concentrations declined as described above, alkylating activity, as assessed by p-nitrobenzyl pyridine reactivity, was stable at all temperatures and pHs tested. Partition coefficients of thiotepa degradation products into toluene, ethyl acetate, diethyl ether, and hexane were determined after 0 and 120 min of incubation in urine at pH 4.0. The extractability of alkylating activity into these organic solvents decreased dramatically after 120 min. Thiotepa degradation products were extracted from urine at pH 4.0 after 0, 30, 60, and 120 min incubation at 37 degrees and were separated by thin-layer chromatography. In addition to thiotepa (Rf 0.15), 3 degradation products possessing p-nitrobenzyl pyridine alkylating activity (Rf 0.35, 0.52, and 0.60) were observed during the course of incubation. The structures of the materials with Rf 0.35 and 0.52 were identified by mass spectrometry and indicated that thiotepa degradation occurs by successive addition of HCl molecules with opening of the aziridine rings and conversion to 2-chloroethyl moieties.

Buffers↗
PubMed1984

Breast reconstruction with the latissimus dorsi musculocutaneous flap.

For breast reconstruction the latissimus flap provides a safe and relatively simple road whose landmarks are familiar to plastic surgeons. These are reviewed. The aesthetic quality of the new breast may depend on a few key planning considerations, one of which is the flap inset site on the anterior chest wall. Theoretic and actual results of using vertical, horizontal, oblique, or curvilinear insets are examined. In many cases ignoring the old scar in favor of a fresh inferolateral curvilinear inset will provide a superior result and is to be strongly considered.

Breast↗
PubMed1983

Neutral amino acid transport in Leishmania promastigotes.

Neutral amino acid transport was investigated in Leishmania promastigotes. Proline and alanine transport occur against their concentration gradient although there is a very rapid (40% at 30 min) conversion of proline to alanine. Uptake of these amino acids occurs by a sodium-independent route which is completely eliminated by addition of CCCP or KCN. Km values for proline and alanine are 80 microM and 63 microM with Vmax values of 6.4 and 7.2 nmol/min per mg dry weight, respectively. Countertransport of proline, alanine and phenylalanine was measured by loading the cells with a variety of neutral amino acids and proline analogs, followed by CCCP addition. The effect of aminooxyacetic acid, an inhibitor of alanine aminotransferase (EC 2.6.1.2), on proline and alanine countertransport was also examined. The results obtained are consistent with the presence of at least two systems for neutral amino acid transport in Leishmania promastigotes.

Alanine↗
PubMed1983

Glucose metabolism in experimental skin flaps.

The metabolism of glucose by rat abdominal skin flaps has been investigated at various times after flap elevation. Biopsies of flap skin taken during the first 3 days after flap elevation and incubated in vitro show a marked increase in glucose consumption and lactate production compared with normal skin. At the same time, flap tissue reserves of glucose and glycogen are lower than those of normal skin. Providing that some circulation persists, the magnitude of the changes in glucose metabolism is proportional to the degree of ischemia experienced by the flap tissue in vivo. In most cases, glucose consumption and lactate production return to normal by the end of the first week after flap elevation. These experiments thus further define a major ischemia-induced shift to anaerobic metabolism (glycolysis) that occurs in skin flaps.

Animals↗
PubMed1983

An innervated cross-finger flap for fingertip reconstruction.

An innervated cross-finger flap for treatment of severe fingertip injuries is described. With this method, the dorsal skin over the middle phalanx, together with its sensory nerve, is transferred as a compound skin-nerve flap. A neurorrhaphy is performed between this nerve and the cut end of the digital nerve at the injury site. Seven of eight patients (88 percent) treated with this method (mean follow-up time 14.4 months) achieved measurable two-point discrimination. The average for those who did was 4.8 mm. A group of patients with similar injuries treated with standard cross-finger flaps exhibited slower sensory return that progressed to a lower level. In this group (mean follow-up time 16.3 months), three of six (50 percent) achieved measurable two-point discrimination with a mean value of 9 mm.

Adult↗
PubMed1983

Relative importance of genetic and nongenetic etiologies in idiopathic mental retardation: estimates based on analysis of medical histories.

A method of analyzing subgroups of mental retardates for proportions of cases caused by nongenetic brain damage is presented here and applied to 490 Israeli retardates. Among mild retardates in simplex and multiplex families with normal unrelated parents, most of the cases were caused by nongenetic brain damage and only a minority were caused by polygenic heredity. Among severe retardates in multiplex families with normal unrelated parents, nongenetic brain damage is probably a more important cause than is homozygosity. In all groups except two (mild retardates with normal consanguineous parents, and severe retardates with retarded parents) the contribution of nongenetic brain damage was surprisingly large.

Brain Damage, Chronic↗
PubMed1983

Biological factors in mild mental retardation.

A group of 434 children with non-syndromic mental retardation was analysed for frequency of recorded prenatal, perinatal and infantile biological disturbances. Mildly retarded individuals for unrelated parentage, both idiopathic and familial, had a strikingly higher prevalence of recorded disturbances than did a control group of retarded individuals with consanguineous parents and of probably genetic aetiology. These disturbances were as frequent among those with mild retardation as among parallel groups with severe retardation. The most significant single disturbance among the mildly retarded was a history of maternal reproductive inefficiency. These findings conflict with the view that mild retardation is predominantly 'cultural-familial' and is not pathological in nature.

Craniocerebral Trauma↗
PubMed1983

Elevated risk of osteoarticular complications in children with acute Brucella melitensis infection.

Infection with brucella microorganisms is considered uncommon in the paediatric age group. We report nine paediatric patients between the ages of 8 to 17 years with acute Brucella melitensis infection, who presented with spiking fever, night sweats, anorexia and malaise for 5 to 60 days prior to diagnosis. Four patients developed various osteoarticular complications: migratory arthralgia, hydroarthrosis of the knees, arthritis and osteomyelitis. Therapy with tetracyclines alone or in combination with streptomycin resulted in complete recovery in eight children. This combination failed in one patient who developed severe osteoarticular disease successfully responding to rifampicin. Since infection of bone and joints leads to irreversible damage, early recognition and immediate management are crucial for recovery. Rifampicin might be of benefit in children with severe osteoarticular complications when the traditional anti-brucella regimen fails.

Adolescent↗
PubMed1982

Effect of anions on the cation selectivity of gramicidin-containing liposomes.

An osmotic method was used to study the salt permeability induced by gramicidin A in liposomes. Sequences of cation permeation were obtained for iodide, salycilate, acetate and formate salts in liposomes below and above their transition temperature. Salycilate and formate salts, unlike acetate and iodide salts, exhibit the same sequences for cation selectivity in liposomes below and above their transition temperature. These results can be explained by assuming three mechanisms for salt permeation across gramicidin-containing liposomes: (i) the anion moves by the lipid part of the membrane whereas the cation moves by the gramicidin channel, (ii) movement of the undissociated acid species occurs through the lipid part of the membrane followed by cation-proton exchange via the gramicidin channel and (iii) the cation and anion may move simultaneously via the gramicidin channel. When the movement of the anion or undissociated acid across the lipid part of the membrane is not rate limiting the permeation process, the cation selectivity obtained agrees with the cation selectivity of the gramicidin A channel, as determined by others using independent measurements.

Anions↗
PubMed1982

Simultaneous posterior and anterior interosseous nerve syndromes.

A patient with simultaneous posterior and anterior interosseous nerve syndromes is presented. During induction of anesthesia, the paralyzed muscles exhibited denervation sensitivity to succinylcholine. Following exploration and repair of a posterior interosseous nerve defect, full function returned in the dorsal muscles as well as the flexor pollicis longus and pronator quadratus muscles.

Adult↗