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Biomedical subjects

H Cohen

Publications and source records attributed to H Cohen.

At least 307 records · Page 17Linked to original sources
PubMed1993

Organic brain dysfunction and cognitive deficits in young schizophrenic patients with tardive dyskinesia.

Tardive dyskinesia (TD) has been associated with cognitive deficits, especially in older psychiatric patients on neuroleptic medication. This study investigated the relationship between presence of TD, organic brain dysfunction (OBD), and cognitive deficits in young psychiatric outpatients maintained on minimal doses of oral neuroleptics, with anticholinergics prescribed only on as-needed basis. Sixty-four patients, aged 20-39 years, were evaluated for the presence of abnormal movements, localizing and nonlocalizing physical signs, and deficits in memory, ability to shift, and sustained attention. Sixteen patients showed definite signs of TD. Significant associations were found between TD and OBD, and between cognitive deficits and OBD, but not between TD and cognitive deficits. Significant regression predictors of TD were the interaction between OBD and previous dystonia, as well as duration of neuroleptic treatment. These findings suggest that some potential risk factors for TD already identified in the literature also apply to younger patients with relatively shorter exposure to neuroleptics. However, the results indicate that the relationship between movement disorders and cognitive deficits may be more apparent in older patients.

Adult↗
PubMed1993

Bismuth subsalicylate suppression of Helicobacter pylori in nonulcer dyspepsia: a double-blind placebo-controlled trial.

Gastritis caused by Helicobacter pylori (HP) is common in patients with nonulcer dyspepsia (NUD), but an etiologic relationship between the histologic lesion and clinical symptoms is unproven. HP is inhibited by bismuth subsalicylate (BSS), a traditional remedy for dyspeptic complaints. The aim of this study was to assess the short- and long-term effects of BSS on HP, gastritis, and symptoms in patients with NUD. One hundred twenty-six patients with NUD who were shown to be infected with H. pylori (HP+) were enrolled. There was a two-week placebo run-in period to eliminate placebo responders. Fifty patients remained symptomatic and were randomly assigned to therapy with either BSS liquid or a matching placebo. EGD, biopsy, and clinical evaluations were performed at entry, at week 5 (end of therapy), at week 9 (four weeks after therapy), or at time of symptomatic relapse. Twenty-seven patients received placebo and 23 patients received BSS. BSS suppressed H. pylori in 15/23 patients (65%) and eradicated it in one patient, whereas the placebo had no effect on H. pylori. Gastritis improved during therapy with BSS but relapsed by week 9. There was no significant change in level of dyspeptic symptoms during or after treatment, although one month after the end of treatment, the patients in the BSS group consistently had lower symptom scores and fewer symptomatic days for all symptoms measured. The study confirms that BSS given for three weeks suppresses but does not usually eradicate H. pylori. Such short-term suppression of H. pylori heals gastritis but does not result in clinical improvement.

Adult↗
PubMed1993

A study of the clinical test of sensory interaction and balance.

BACKGROUND AND PURPOSE: The ability to maintain an upright position during quiet standing is a useful motor skill. The Clinical Test of Sensory Interaction and Balance is an inexpensive, easily administered test that provides information about the ability to stand upright under several sensory conditions. SUBJECTS: Three groups of neurologically asymptomatic (AS) adults, divided by age into younger, middle-aged, and older groups, participated in the study. A fourth group comprised subjects diagnosed with vestibular disorders. METHODS: Timed performances under six different conditions were compared across groups. RESULTS: Subjects with vestibular disorders were significantly impaired on performance when compared with age-matched AS subjects. Older AS and vestibularly impaired subjects had greater variation in their scores than did younger AS subjects. CONCLUSION AND DISCUSSION: This test is a useful screening tool for examining static standing balance.

Adult↗
PubMed1993

Decreased contact factor mediated fibrinolysis in cirrhosis.

We studied extrinsic and intrinsic fibrinolysis in 20 patients with cirrhosis (nine mild/moderate, group 1; 11 severe, group 2) and 19 normal controls to define the role of intrinsic (contact factor medaited) fibrinolysis in cirrhosis. Global plasma fibrinolytic activity (fibrin plate lysis) was similar in all groups. Dextran sulphate activated contact factor mediated fibrinolysis was decreased in group 2 (median 95.2%) compared with group 1 (121.0%) and controls (131.7%). Tissue plasminogen activator antigen (t-PA Ag) levels were increased in group 2 (28.2 ng/ml) compared both with group 1 (8.5 ng/ml) and controls (5.9 ng/ml). Plasma t-PA activity was raised in group 2 (5.50 IU/ml) and group 1 (5.25 IU/ml) versus controls (0.82 IU/ml). Plasminogen activator inhibitor-1 (PAI-1 Ag) levels were raised in group 2 (28.0 IU/ml) versus controls (8.5 IU/ml) but PAI activity was similar in all groups. Factor XII activity was decreased in group 2 (48.76 u/dl), but not group 1, versus controls (89.1 u/dl). Prekallikrein activity was decreased both in group 2 (27.27 u/dl) and group 1 (33.01 u/dl) versus controls (108.59 u/dl) and was lower in group 2 than group 1. C1-esterase inhibitor chromogenic activity was decreased in group 1 (102.30 u/dl) and group 2 (58.76 u/dl) versus controls (116.24 u/dl). The normal global fibrinolytic activity despite increased t-PA activity may be due to a concomitant increase in PAI. The decreased intrinsic fibrinolysis in severe cirrhosis, unaccompanied by a rise in C1-esterase inhibitor, may be explained by the decreased factor XII and prekallikrein activity. These changes are probably due to reduced liver cell mass.

Adult↗
PubMed1993

Detection of immunoglobulin G antibodies to Helicobacter pylori in urine by an enzyme immunoassay method.

Urine and serum samples from 306 patients undergoing upper endoscopy were evaluated prospectively to determine the presence of immunoglobulin G (IgG) antibodies to Helicobacter pylori by an enzyme immunoassay method. Forty-nine selected urine specimens were also tested by Western blotting (immunoblotting). When compared with bioptic methods (culture, stain, urease testing), the sensitivity and specificity of the assay for urine IgG to H. pylori were 95.9 and 90%, respectively. Results of testing of serum and urine for IgG to H. pylori were concordant for 95% of samples. Western blot analysis revealed a highly variable antibody response to H. pylori antigens among patients. Detection of IgG antibody to H. pylori in urine is simple and reflects the presence or absence of H. pylori infection.

Adolescent↗
PubMed1993

Referral of patients to an anticoagulant clinic: implications for better management.

The quality of anticoagulant treatment of ambulatory patients is affected by the content of referral letters and administrative processes. To assess these influences a method was developed to audit against the hospital standard the referral of patients to one hospital anticoagulant clinic in a prospective study of all (80) new patients referred to the clinic over eight months. Administrative information was provided by the clinic coordinator, and the referral letters were audited by the researchers. Referral letters were not received by the clinic for 10% (8/80) of patients. Among the 72 referral letters received, indication for anticoagulation and anticipated duration of treatment were specified in most (99%, 71 and 81%, 58 respectively), but only 3% (two) to 46% (33) reported other important clinical information (objective investigations, date of starting anticoagulation, current anticoagulant dose, date and result of latest international normalised ratio, whether it should be the anticoagulant clinic that was eventually to stop anticoagulation, patients' other medical problems and concurrent treatment. Twenty two per cent (16/80) of new attenders were unexpected at the anticoagulant clinic. Most patients' case notes were obtained for the appointment (61%, 47/77 beforehand and 30% 23/77 on the day), but case notes were not obtained for 9% (7/77). The authors conclude that health professionals should better appreciate the administrative and organisational influences that affect team work and quality of care. Compliance with a well documented protocol remained below the acceptable standard. The quality of the referral process may be improved by using a more comprehensive and helpful referral form, which has been drawn up, and by educating referring doctors. Measures to increase the efficiency of the administrative process include telephoning the clinic coordinator directly, direct referrals through a computerised referral system, and telephone reminders by haematology office staff to ward staff to ensure availability of the hospital notes. The effect of these changes will be assessed in a repeat audit.

Adolescent↗
PubMed1993

Characterization of a prolactin binding protein in rat serum.

To determine the presence of a PRL-binding protein (PRL-BP) in rat serum, female rats were ovariectomized and administered sc estradiol benzoate capsules. Serum was incubated with [125I]rat PRL (rPRL) for 1 h at 37 C with or without different doses of rPRL, ovine PRL (oPRL), or rGH. Separation of the [125I]rPRL-PRL-BP complex from unbound [125I]rPRL was accomplished by Sephadex G100 chromatography or by precipitation with an antibody against rat liver PRL receptor. Results showed that a protein was able to bind specifically to rPRL or oPRL, but not to rGH. Scatchard plots gave an affinity constant of 1.18 +/- 0.7 10(9) M-1 and a capacity of 11.24 +/- 1.4 nM. The complex [125I]rPRL-PRL-BP migrated in the void volume of sephadex G100 column, but with an apparent mol wt of 80K after cross-linking and electrophoresis under reducing conditions. PRL BP was purified from estradiol-treated ovariectomized females by an oPRL sepharose 4B affinity column. Purified protein migrated under reducing conditions with apparent mol wt of 50K and 27K but of 160K under nonreducing conditions. After transfer on nitrocellulose filter, the 160K, 50K and 27K forms were able to bind to monoclonal antibodies directed against rat liver PRL receptor. The 160K and 50K were still able to bind to [125I]oPRL, but not the 27K. These results showed that rat serum contained a PRL-BP, which presented a strong homology to PRL receptor, at least for the immunological and binding characteristics.

Animals↗
PubMed1993

Normal rat uterine stromal cells in continuous culture: characterization and progestin regulation of growth.

Stromal cells were isolated from rat uterus by sequential enzymatic digestion and density fractionation on Percoll gradient and subcultured by trypsinization. Two stable subcultures, named UII and UIII, were obtained. UII cells exhibited a spindle-shaped, elongated, fibroblast-like morphology, while UIII cells were rounded and polygonal. Both cell types expressed the intermediate filament vimentin but not cytokeratin, nor desmin, suggesting that both were of stromal origin. In UIII cells, the presence of progesterone and prolactin (PRL) receptors was demonstrated by immunocytochemical and binding studies. Cross-linking and Western blotting showed that PRL receptor in UIII cells corresponded to 3 molecular forms of 54, 42 and 32 kDa. The growth properties of these cells were studied under different conditions of culture. In fetal calf serum (FCS) supplemented medium, proliferation of UIII cells was dependent on serum concentration and was not affected by estradiol and progesterone. In 10% FCS supplemented medium, the doubling time was 41.5 +/- 0.8 h. When cultured in 10% dextran-charcoal-treated FCS, cells were maintained in a viable but quiescent state. Under these conditions, progesterone was able to induce growth of these cells in a dose-dependent manner. A 3-fold increase in DNA content was measurable in 10(-7) M progesterone-treated versus control cultures after 5 days. Reduction of serum concentration from 10% to 2% abolished the effect of progesterone suggesting that this effect requires the presence of serum factor(s). In conclusion, this study showed that uterine stromal cells, in continuous culture, retained progesterone and prolactin receptors and progesterone regulation of growth.

Animals↗
PubMed1993

Audit of start of anticoagulation treatment in inpatients.

AIMS: To develop a method for evaluating the start of anticoagulation treatment in inpatients. METHODS: One hundred case notes were audited using a proforma based on local guidelines in accordance with British Society for Haematology recommendations. RESULTS: Confirmatory investigations were done in 93% and 79% of patients with symptomatic deep venous thrombosis and pulmonary embolism, respectively. Identification of patients' risk factors for anticoagulation by history taking and laboratory tests was often inadequate: baseline coagulation screen, platelet count, liver function and renal function tests were done in 52%, 95%, 70% and 87% of cases, respectively. There was a tendency to undertreat patients: 33% of the activated partial thromboplastin times (APTT) and 58% of the International Normalised Ratios (INR) were subtherapeutic. The heparin-warfarin crossover period was particularly problematic: 37% stopped heparin without an INR that day, or had an INR of less than 2. Microscopic haematuria was monitored occasionally. Of the 62 patients continuing anticoagulation, 72% were discharged with the final INR in the therapeutic range. At discharge, only 74% of patients had documented appointments for the anticoagulant Clinic, the period between discharge and appointment ranging from 0 to 12 days. Of the 25 cases with an appointment exceeding four days after discharge, only six (24%) had arrangements for an interim INR check. CONCLUSIONS: The experience allowed the proforma to become streamlined to a more practical, reliable, and valid tool for use elsewhere. Findings will be fed back to the hospital staff to promote practice improvements before closing the audit loop by re-evaluating practice. Further studies are in progress to identify barriers experienced by doctors in implementing the guidelines and problems in the process of referral to the anticoagulant clinic.

Adult↗
PubMed1993

Common-sense management of Helicobacter pylori-associated gastroduodenal disease. Personal views.

We have tried to present a rational approach to the medical treatment of peptic ulcer disease and nonulcer dyspepsia in the era of H. pylori. We are aware that the natural history of peptic ulcer disease is still debated. Some clinicians believe that peptic ulcer disease may "burn out" over a 10- to 15-year period, and in light of this, the emphasis toward a nonsurgical "cure" for peptic ulcer disease may seem misguided. Yet, all factors must be taken into account. Current medical therapy has demonstrated inadequacies. H. pylori is unequivocally (in our view) associated with peptic ulcer disease. Anti-H. pylori therapy has proven efficacy in the long-term prevention of peptic ulcer recurrence. Despite our enthusiasm for treatment of H. pylori in select circumstances, we encourage further controlled clinical trials to better delineate the role of H. pylori in the natural history and treatment of peptic ulcers. The association between H. pylori and nonulcer dyspepsia is tenuous at best. Treatment directed at eradicating H. pylori in nonulcer dyspepsia does not impress us favorably. We are intrigued by preliminary data that, despite a lack of improvement in the short term, H. pylori eradication in nonulcer dyspepsia patients may reduce symptoms over the long term. Unfortunately, this study suffers methodologic difficulties. If other studies were to confirm these findings, this would provide a cogent reason for us to reassess our views on the treatment of H. pylori in nonulcer dyspepsia. At present, the costs, benefits, and risks of anti-H. pylori therapy in nonulcer dyspepsia are not sufficient to warrant its use outside of therapeutic trials.

Dyspepsia↗
PubMed1992

Guanidinium derivatives act as high affinity antagonists of Na+ ions in occlusion sites of Na+,K(+)-ATPase.

We have screened various alkyl- and arylguanidinium derivatives as possible competitors of Na+ or Rb+ for the cation sites on renal Na+,K(+)-ATPase. Alkyl-monoguanidinium or alkylbisguanidinium (BisG) compounds (chain lengths of C3 to C10) competitively inhibit the occlusion of Rb+ and Na+ with an order of affinities C10 greater than C8 greater than C6 greater than C4 greater than C3. BisG compounds are approximately twice as effective as the equivalent alkylmonoguanidinium compounds. In media of high ionic strength, affinities of tens of micromolar are observed, e.g. 26 microM for BisG 8. m-(mXBG)- and p-xylylenebisguanidinium were synthesized and were found to compete with Rb+ or Na+ with intrinsic affinities of 7.7 and 8.2 microM, respectively. The hydrophobicity rather than the degree of proximity of the guanidinium groups in all BisG compounds appears to determine the binding affinity. A systematic search has been made of conditions in occlusion assays for which the inhibitor affinities are highest. When the pH is raised from 7.0 to 8.5, a 5-fold increase in affinity is observed, suggesting that the guanidinium derivatives compete with protons at sites of pKa approximately 7.5. Replacing Tris-HCl with choline chloride-containing media raised apparent affinities approximately 2-fold. All guanidinium derivatives stabilize the E1 conformation of fluorescein-labeled Na+,K(+)-ATPase, acting as competitive Na+ analogues. In media containing only 1 mM Tris-HCl, pH 8.55, very high affinities were observed for binding to the fluorescein-labeled enzyme (e.g. 0.08 microM for mXBG). In very low ionic strength medium, the inhibition was still competitive with Rb+ ions. However, there was also evidence for nonspecific adsorption to the membranes. The following findings show that mXBG, a typical guanidinium derivative, behaves as a Na(+)-like antagonist. (a) It inhibits Na+,K(+)-ATPase activity, competing strongly with Na+ but only weakly with K+ ions. (b) It inhibits phosphorylation from ATP, competing with Na+ ions. (c) Like Na+ ions, it blocks phosphorylation from inorganic phosphate. Based on these results, we propose that the guanidinium group binds to a relatively wide vestibule at the cytoplasmic surface; but, unlike Na+ or K+ ions, it cannot pass into a narrower region of the cation transport path within the membrane. Therefore, it blocks the occlusion and active transport of cations. In the future, high affinity guanidinium derivatives may serve the purpose of locating cation-binding domains of the pump protein after being converted to reactive affinity or photoaffinity covalent labels.

Animals↗
PubMed1992

Habituation and adaptation of the vestibuloocular reflex: a model of differential control by the vestibulocerebellum.

We habituated the dominant time constant of the horizontal vestibuloocular reflex (VOR) of rhesus and cynomolgus monkeys by repeated testing with steps of velocity about a vertical axis and adapted the gain of the VOR by altering visual input with magnifying and reducing lenses. After baseline values were established, the nodulus and ventral uvula of the vestibulocerebellum were ablated in two monkeys, and the effects of nodulouvulectomy and flocculectomy on VOR gain adaptation and habituation were compared. The VOR time constant decreased with repeated testing, rapidly at first and more slowly thereafter. The gain of the VOR was unaffected. Massed trials were more effective than distributed trials in producing habituation. Regardless of the schedule of testing, the VOR time constant never fell below the time constant of the semicircular canals (approximately 5 s). This finding indicates that only the slow component of the vestibular response, the component produced by velocity storage, was habituated. In agreement with this, the time constant of optokinetic after-nystagmus (OKAN) was habituated concurrently with the VOR. Average values for VOR habituation were obtained on a per session basis for six animals. The VOR gain was adapted by natural head movements in partially habituated monkeys while they wore x 2.2 magnifying or x 0.5 reducing lenses. Adaptation occurred rapidly and reached about +/- 30%, similar to values obtained using forced rotation. VOR gain adaptation did not cause additional habituation of the time constant. When the VOR gain was reduced in animals with a long VOR time constant, there were overshoots in eye velocity that peaked at about 6-8 s after the onset or end of constant-velocity rotation. These overshoots occurred at times when the velocity storage integrator would have been maximally activated by semicircular canal input. Since the activity generated in the canals is not altered by visual adaptation, this finding indicates that the gain element that controls rapid changes in eye velocity in the VOR is separate from that which couples afferent input to velocity storage. Nodulouvulectomy caused a prompt and permanent loss of habituation, returning VOR time constants to initial values. VOR gain adaptation, which is lost after flocculectomy, was unaffected by nodulouvulectomy. Flocculectomy did not alter habituation of the VOR or of OKAN. Using a simplified model of the VOR, the decrease in the duration of vestibular nystagmus due to habituation was related to a decrement in the dominant time constant of the velocity storage integrator (1/h0).(ABSTRACT TRUNCATED AT 400 WORDS)

Acclimatization↗
PubMed1992

Prospective evaluation of immediate versus delayed refeeding and prognostic value of endoscopy in patients with upper gastrointestinal hemorrhage.

The effects of immediate vs. delayed refeeding and the prognostic value of endoscopic findings in patients with major upper gastrointestinal hemorrhage were assessed in a prospective randomized study. Entry criteria were clinical evidence of major hemorrhage and endoscopic evidence of a Mallory-Weiss tear or an ulcer with a clean base, flat spot, or clot. Two hundred fifty-eight patients were randomly assigned to groups receiving a regular diet immediately or nothing by mouth for 36 hours, then clear liquids for 12 hours, and a regular diet thereafter. Outcomes in the immediate and delayed refeeding groups were comparable: rebleeding occurred in 4% vs. 5%; urgent intervention, 2% vs. 2%; and deaths, 1% vs. 1%, respectively. Rebleeding occurred in 2 (2%) of 96 patients with cleanbased ulcers, 5 (8%) of 65 with ulcers with spots, 3 (14%) of 21 with ulcers with clots (P = 0.05, 3 x 2 chi2 test), and 1 (2%) of 66 with Mallory-Weiss tears. It is concluded that the time of refeeding does not influence the hospital course of patients with a low risk of recurrent bleeding. Patients with clean-based ulcers or nonbleeding Mallory-Weiss tears may be refed and discharged home immediately after stabilization.

Endoscopy↗
PubMed1992

Differential regulation of the rat phosphoenolpyruvate carboxykinase gene expression in several tissues of transgenic mice.

The selective expression of a unique copy gene in several mammalian tissues has been approached by studying the regulatory sequences needed to control expression of the rat phosphoenolpyruvate carboxykinase (PEPCK) gene in transgenic mice. A transgene containing the entire PEPCK gene, including 2.2 kb of the 5'-flanking region and 0.5 kb of the 3'-flanking region, exhibits tissue-specific expression in the liver, kidney, and adipose tissue, as well as the hormonal and developmental regulation inherent to endogenous gene expression. Deletions of the 5'-flanking region of the gene have shown the need for sequences downstream of position -540 of the PEPCK gene for expression in the liver and sequences downstream of position -362 for expression in the kidney. Additional sequences upstream of position -540 (up to -2200) are required for expression in adipose tissue. In addition, the region containing the glucocorticoid-responsive elements of the gene used by the kidney was identified. This same sequence was found to be needed specifically for developmental regulation of gene expression in the kidney and, together with upstream sequences, in the intestine. The apparently distinct sequence requirements in the various tissues indicate that the tissues use different mechanisms for expression of the same gene.

Aging↗