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Biomedical subjects

L Cohen

Publications and source records attributed to L Cohen.

At least 253 records · Page 14Linked to original sources
PubMed1992

Posterior upper cervical fusion in rheumatoid arthritis.

The purpose of this study was to determine fusion rates in patients who underwent posterior cervical fusion for instability of the upper cervical spine secondary to rheumatoid arthritis. A retrospective review of clinical and radiographic data was conducted. Nineteen patients underwent posterior cervical fusions limited to the upper cervical spine. There were 11 C1-C2 fusions and 8 occiput-C2 fusions. Instability with pain or neurologic deficits were the main indications. A uniform technique was used in all cases. Preoperative reduction in halo vest or cast was followed by a Gallie type fusion using autogenous iliac bone graft and wire, and postoperative halo vest or cast immobilization for 3 months. A fusion rate of 94% was achieved. The average follow-up was 5 years. Complete or partial relief of pain was obtained in all patients; 30% of those with preoperative deficits improved after surgery. A high fusion rate may be achieved with C1-C2 and occiput-C2 fusions in rheumatoid arthritis, with relief of pain and prevention of neurologic deterioration.

Adult↗
PubMed1992

Personality in panic disorder with agoraphobia: a Rorschach study.

In this study, we tested several hypotheses derived from self psychology (Diamond, 1987) regarding personality features of patients suffering from panic disorder and agoraphobia (PDA). PDA patients are thought to suffer from a deficit in negative affect-regulating capacity, surrounded by defenses such as avoidance, repression, denial, and reaction formation against dependency needs. These defenses are thought to lead to a greatly impoverished affective life. The Rorschach Comprehensive System was used to assess the personality features of avoidance, restricted affective life, and reaction formation against dependency needs. We found evidence for the presence of a highly avoidant information-processing style (86% of protocols had lambda [L] greater than .99) and a constricted affective life (low weighted sum color [WSumC] and low affective ratio [Afr]). Our results were consistent with the hypothesis of reaction formation against dependency needs (low food content [Fd]). Findings are discussed in light of studies that found a high incidence of avoidant personality disorder in PDA patients.

Adult↗
PubMed1992

Subcutaneous administration of HMG-CoA reductase inhibitors in hyperlipidaemic and normal rats.

Recent reports demonstrate a hypocholesterolaemic effect of daily subcutaneous injections of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in different rat models of hyperlipidaemia. However, this effect is not seen after oral administration of HMG-CoA reductase inhibitors in rats. We found that oral administration of the HMG-CoA reductase inhibitor Simvastatin also had no effect on plasma cholesterol in severely hyperlipidaemic Nagase analbuminaemic rats (NAR). Simvastatin (an apolar compound dissolved in propylene glycol) was infused continuously for 28 days into the subcutis of control Sprague-Dawley rats (SDR) and NAR using an implanted osmotic pump. All doses which were effective in reducing cholesterol in the NAR (reductions up to approximately 60%), reduced apolipoprotein AI but not apolipoprotein B and caused a severe inflammatory reaction in the dermis. Similar toxicity was observed in the SDR. Subcutaneous administration of the vehicle (propylene glycol) did not cause this reaction and did not affect plasma lipids. Administration of Lovastatin in osmotic pumps resulted in a similar inflammatory reaction. Incorporation of Simvastatin into liposomes did not diminish the toxic effect. On the other hand, infusion of Pravastatin (a polar HMG-CoA reductase inhibitor dissolved in isotonic saline) caused no changes in the dermis and had no effect on plasma lipids in NAR or SDR. Liver microsomes prepared from the Pravastatin-treated rats demonstrated a 3- to 4-fold increase in HMG-CoA reductase activity as compared to untreated rats, confirming uptake of the drug. We conclude that continuous subcutaneous administration of the HMG-CoA reductase inhibitors Simvastatin, Lovastatin and Pravastatin for 28 days may not reduce plasma cholesterol in rats by a mechanism which is related to inhibition of HMG-CoA reductase activity in the liver. The decrease of plasma cholesterol effected by subcutaneous infusion of Simvastatin or Lovastatin in NAR coincides with, and may be related to inflammatory changes caused by administering these compounds into the dermis.

Administration, Oral↗
PubMed1992

Heterotopic pregnancy with discordant ultrasonic appearance of fetal cardiac activity.

In an interesting experiment of nature, we observed the discordant onset of fetal cardiac activity between the two gestations of a heterotopic pregnancy. After initially detecting cardiac activity only in the tubal gestational sac, we later observed cardiac activity in the intrauterine sac 6 days after laparoscopic salpingectomy. This case illustrates the variable onset of cardiac activity. We advise expectant management of the intrauterine pregnancy in a heterotopic gestation when cardiac activity is not detected initially in the intrauterine sac.

Adult↗
PubMed1992

[Selective sensitivity of cysts to praziquantel and albendazole in a case of cerebral cysticercosis].

A case of neurocysticercosis in a Zaïrian patient with clinical and neuro-radiological follow-up is reported. Treatment with praziquantel resulted in the regression of only some of the cysts. Subsequent treatment with albendazole was effective, eliminating most of the remaining lesions. This case illustrates a selective sensitivity of cysts to praziquantel and albendazole in a single patient.

Adult↗
PubMed1991

Peroxisomal enzyme activities in the human hepatoblastoma cell line HepG2 as compared to human liver.

In order to develop an in vitro model allowing investigation of the long-term effects of hormones and other agents on peroxisomes in liver cells, we measured the activity of a series of peroxisomal enzyme activities in HepG2 cells, a proliferating cell line derived from a human hepatoblastoma. The results obtained show that although in absolute terms peroxisomal enzyme activities are lower in HepG2 cells as compared to human liver, relative activities were comparable in HepG2 and human liver, respectively. Furthermore, it is shown that peroxisomes can easily be isolated from HepG2 cells using density gradient centrifugation. It is concluded that HepG2 cells represent a good model system to study the characteristic (long-term) regulation and control of metabolism of human liver peroxisomes.

Carcinoma, Hepatocellular↗
PubMed1991

Evidence of limited variability of antigen receptors on intrathyroidal T cells in autoimmune thyroid disease.

BACKGROUND: Patients with autoimmune thyroid diseases, including Graves' disease and Hashimoto's disease, have marked lymphocytic infiltration in their thyroid glands. We examined the gene for the variable regions of the alpha-chain of the human T-cell receptor (the V alpha gene) in intrathyroidal T cells to determine whether the infiltration is a secondary heterogeneous immune response or a more restricted, and therefore primary and presumably pathogenetic, reaction to thyroid autoantigens. METHODS: We used the polymerase chain reaction to detect small numbers of T cells expressing the variable region of the V alpha gene. Different oligonucleotides were used to amplify complementary DNA for the 18 known families of the V alpha gene in intrathyroidal T cells from 9 patients with autoimmune thyroid disease. We compared the findings with the results in patients with nonautoimmune thyroid disease as well as those in normal subjects. RESULTS: We found marked restriction in the expression of T-cell-receptor V alpha genes by T cells from the thyroid tissue of patients with autoimmune thyroid disease. An average of only 5 of the 18 V alpha genes were expressed in such samples, as compared with 17 V alpha genes expressed in peripheral-blood T cells from the same patients. No such restriction was found in thyroid tissue from patients with nonautoimmune thyroid disease. The predominantly expressed V alpha genes differed from patient to patient, however, with no clear association with the type of disease. CONCLUSIONS: Intrathyroidal T-cell accumulation in autoimmune thyroid disease is highly restricted and points to the primacy of T cells in causing thyroid disorders. These results present the possibility of using antibodies to the T-cell receptor for the specific inhibition of abnormal T-cell function in autoimmune thyroid disease.

Antigens, CD↗
PubMed1991

Restricted T-cell receptor V beta gene usage by myelin basic protein-specific T-cell clones in multiple sclerosis: predominant genes vary in individuals.

Recent studies in experimental autoimmune encephalomyelitis as a model for multiple sclerosis (MS) have demonstrated limited heterogeneity in T-cell antigen receptors (TCR) specific for myelin basic protein (MBP). To investigate restricted beta-chain variable-region (V beta) gene usage in humans, we analyzed TCR gene rearrangements in two lines and 34 MBP-specific T-cell clones that were isolated from five MS patients and two healthy subjects. The T cells were characterized for their specificity to MBP epitopes and HLA-restricting molecules. We demonstrate here that MBP-specific T-cell clones from these different MS patients and healthy individuals, in contrast to T cells from rodents, display a more diverse V beta gene usage as evidenced by their TCR V beta gene rearrangements. However, the different MBP-specific T-cell clones isolated from each individual MS patient showed a common V beta gene usage, suggesting individual-specific TCR restriction. Out of 16 MBP-specific clones derived from a single MS patient, 12 clones (75%) utilized the V beta 15 gene for their TCR gene rearrangement. MBP-specific clones isolated from four other MS patients also showed a consistent tendency for a predominant, but different, TCR V beta gene rearrangement. These results suggest a TCR heterogeneity among MBP-specific T-cell clones from different individuals but a limited TCR V beta gene usage among MBP-specific T-cell clones of the same individual. The predominant V beta gene used by the MBP-specific T-cell clones studied here was not found to correlate with the epitope specificity of T cells or with their restricting HLA molecule. These findings may support the possibility of intervention with monoclonal antibodies to specific V beta gene products as an approach to immune therapy of MS but also imply the necessity for an individual-specific immunotherapeutic approach.

Base Sequence↗
PubMed1991

Modified Blalock Taussig shunt anastomosis in a three month old child with pulmonary stenosis: embolization therapy.

A case of transcatheter occlusion of a modified Blalock-Taussig (BT) shunt with a detachable balloon is described. A three month old boy with pulmonary atresia with intact ventricular septum had a repair consisting in valvotomy and a modified BT. This palliative aorticopulmonary shunt created congestive heart failure. As an alternative to surgery, a detachable balloon was used to occlude the BT shunt.

Anastomosis, Surgical↗
PubMed1991

Two mental calculation systems: a case study of severe acalculia with preserved approximation.

We report the case of an aphasic and acalculic patient with selective preservation of approximation abilities. The patient's deficit was so severe that he judged 2 + 2 = 5 to be correct, illustrating a radical impairment in exact calculation. However, he easily rejected grossly false additions such as 2 + 2 = 9, therefore demonstrating a preserved knowledge of the approximate result. The dissociation between impaired exact processing and preserved approximation was identified in several numerical tasks: solving and verifying arithmetical operations, number reading, short-term memory, number comparison, parity judgement, and number knowledge. We suggest the existence of two distinct number-processing routes in the normal subject. One route permits exact number representation, memory and calculation using symbolic notation. The other route allows for approximate computations using an analog representation of quantities.

Adult↗