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Biomedical subjects

S Cohen

Publications and source records attributed to S Cohen.

At least 91 records · Page 5Linked to original sources
PubMed2001

Continuous thoracic epidural anesthesia with 0.2% ropivacaine versus general anesthesia for perioperative management of modified radical mastectomy.

We evaluated in this prospective study the effectiveness of continuous thoracic epidural anesthesia (TEA) and postoperative analgesia with ropivacaine and compared it with general anesthesia (GA) and opioids for pain relief, side effects, postanesthesia recovery, and hospital discharge after modified radical mastectomy. Sixty ASA physical status II and III patients undergoing mastectomy were randomly assigned to two study groups of 30 patients each. In the TEA group, an epidural catheter was inserted at T6-7, and 5--10 mL of 0.2% ropivacaine was injected to maintain anesthesia and to continuously administer adequate analgesia for 48 h. GA was induced with IV 1--2 mg of midazolam or 50--100 microg/mL of fentanyl followed by 50--150 mg of propofol and was maintained with sevoflurane and 50% N(2)O in oxygen. The Aldrete score system was used to evaluate postanesthesia recovery, a verbal rating scale was used for assessment of pain intensity, and a postanesthesia discharge scoring system was used for discharge home. The demographic data and side effects (except for nausea and vomiting) (GA 43%, TEA 10%, P = 0.0074) and discharge home were similar in both groups. However, the number of patients ready for discharge from the recovery room during the first postanesthesia hour (Aldrete score of 10) was significantly larger after TEA (80%) than after GA (33%) (P = 0.0006). GA patients experienced significantly more (P < 0.001) substantial pain than TEA patients on Day 0 (70%), Day 1 (53%), and Day 2 (27%) after the surgery. Patient satisfaction was greater with TEA (70%) than with GA (30%) (P < 0.001). We conclude that TEA with ropivacaine provides better postoperative pain relief and less nausea and vomiting, facilitates postanesthesia recovery, and gives greater patient satisfaction than GA.

Adult↗
PubMed2001

Meeting expectations?

Tips for planning and conducting productive staff meetings.

Attitude of Health Personnel↗
PubMed2001

Challenges influencing the future of endodontics. New technologies for endodontic education.

The major challenge of contemporary dental education is teaching students to transfer their acquired knowledge from one setting to another. New technology-based educational tools such as IMPACT, Interactive Multimedia Patient Case Tutor, developed at the Virginia Commonwealth University School of Dentistry, can assist in this educational paradigm shift by teaching students basic science in the context of patient dental problems. The interactivity of technology as used in the IMPACT program links students' basic science knowledge base to the description, understanding and solution of patient problems.

Computer-Assisted Instruction↗
PubMed2001

Effects of morphine and naloxone on fetal heart rate and movement in the pig.

To test the hypothesis that an increasing opioid tonus is involved in decreases in fetal heart rate (FHR) and movement (FM) during late gestation, we studied the effects of intravenous bolus injections of morphine (1 mg) and naloxone (1 mg) on FHR and FM in the fetal pig. Twenty-one fetuses (1 per sow) were catheterized at 90-104 days of gestation (median 100 days). Recordings of FHR (electrocardiograph or Doppler-derived signals) and FM (ultrasonography) were made from 15 min before to 45 min after treatment. Morphine administration significantly decreased FHR, but it increased FHR variation and forelimb movements (LM). LM were clustered, and this stereotyped behavior has never before been observed in any mammalian fetus. Naloxone administration increased gross body movements and FHR without significant changes in FHR variation. It is concluded that FHR and motility are under opioidergic control in the pig fetus. Both morphine and naloxone induce hypermotility, suggesting that naloxone does not act as a pure opioid antagonist in the fetal pig.

Analgesics, Opioid↗
PubMed2001

Amantadine increases gait steadiness in frontal gait disorder due to subcortical vascular encephalopathy: a double-blind randomized placebo-controlled trial based on quantitative gait analysis.

In a randomized, double-blind placebo-controlled trial, 40 patients diagnosed as subcortical vascular encephalopathy (SVE) were given a daily dose of 500 ml i.v. amantadine vs. placebo for 5 days. Both groups were treated with physiotherapy on a daily basis. Quantitative gait analyses were performed at days 1 and 6 to evaluate gait steadiness from cadence, length of heel-to-toe movements, variability of centre of gravity (COG) and double support time. Both placebo- and amantadine-receiving patient groups showed mild improvement in gait parameters after study, which failed to show the superiority of amantadine, when comparing drug-induced changes between both groups. However, analysing the treatment effects from day 0 to day 6 in both groups separately, statistically significant changes could be found in the amantadine group for cadence, length of heel-to-toe movements in single support phase as well as for variability in double support phase and double support time (two-tailed paired t-test, p < 0.05), whereas in the placebo group, a statistically significant effect could only be seen for double support time (p < 0.05). In this small pilot study, amantadine tends to improve gait steadiness as evaluated by cadence, length of heel-to-toe movements in single support phase, variability in double support phase and double support time, in patients with moderate frontal gait disorder due to SVE. Improvements in the placebo group can be interpreted as physiotherapy effect, which improved gait steadiness slightly, however, this was statistically significant only for double support time.

Amantadine↗
PubMed2001

Renal effects of nabumetone, a COX-2 antagonist: impairment of function in isolated perfused rat kidneys contrasts with preserved renal function in vivo.

The constitutive cyclooxygenase (COX)-1 enzyme has been considered the physiologically important isoform for prostaglandin synthesis in the normal kidney. It has, therefore, been suggested that selective inhibitors of the 'inducible' isoform (COX-2) may be free from renal adverse effects. We studied the renal effects of the predominantly COX-2 antagonist nabumetone in isolated perfused kidneys. As compared with controls, kidneys removed after in vivo administration of oral nabumetone (15 mg/kg) disclosed altered renal function with reduced glomerular filtration rate, filtration fraction, and urine volume and enhanced hypoxic outer medullary tubular damage. By contrast, renal function and morphology were not affected in vivo by nabumetone or its active metabolite 6-methoxy-2-naphthylacetic acid. The latter agent (10-20 mg/kg i.v.) did not significantly alter renal microcirculation, as opposed to a selective substantial reduction in medullary blood flow noted with the nonselective COX inhibitor indomethacin (5 mg/kg i.v.). In a rat model of acute renal failure, induced by concomitant administration of radiocontrast, nitric oxide synthase, and COX inhibitors, the decline in kidney function and the extent of hypoxic medullary damage with oral nabumetone (80 mg/kg) were comparable to a control group, and significantly less than those induced by indomethacin. In rats subjected to daily oral nabumetone for 3 consecutive weeks, renal function and morphology were preserved as well. Both nabumetone and 6-methoxy-2-naphthylacetic acid reduced renal parenchymal prostaglandin E2 to the same extent as indomethacin. It is concluded that while nabumetone adversely affects renal function and may intensify hypoxic medullary damage ex vivo, rat kidneys are not affected by this agent in vivo, both in acute and chronic studies. COX selectivity may not explain the renal safety of nabumetone.

Acute Kidney Injury↗
PubMed2001

Weight gain with risperidone among patients with mental retardation: effect of calorie restriction.

BACKGROUND: The atypical antipsychotics cause weight gain, which is poorly understood in terms of its mechanism and treatment. A usual recommendation for treatment of antipsychotic-induced weight gain includes calorie restriction and exercise. The authors describe their recent clinical experience with calorie restriction in adults with mental retardation treated with risperidone. METHOD: A retrospective chart review was performed on the records of 50 adult patients with mental retardation treated with risperidone while residing at a habilitation center. We assessed dose and duration of risperidone treatment, weight, changes in calorie intake, and frequency of aggressive behavior. RESULTS: Of the 50 patients, 39 had adequate data for analysis. Thirty-seven of the 39 patients gained weight with a mean of 18.8 lb (8.3 kg) over about 2 years. Twenty of the 37 patients were calorie restricted. Three of the 20 calorie-restricted patients lost weight at a rate of 0.2 lb (0.1 kg) per month. The other 17 calorie-restricted patients and the 17 patients who were not calorie restricted continued to gain weight at a rate of 0.8 lb (0.4 kg) per month over about another 2 years of treatment. The amount of weight gain was not dose related. Calorie restriction led to no deterioration in behavior. CONCLUSION: The current investigation lends support to data that note weight gain with risperidone in adults with mental retardation. It suggests that calorie restriction does not lead to weight loss or behavioral deterioration and that weight gain is not dose related.

Aggression↗
PubMed2001

Mesiotemporal T2-weighted hyperintensity: neurosyphilis mimicking herpes encephalitis.

Bilateral mesiotemporal hyperintensity on T2-weighted and fluid-attenuated inversion recovery MR images of a patient with a clinical syndrome of encephalitis is considered to be a classic finding for herpes simplex virus infection. We report a case of neurosyphilis with identical MR imaging abnormalities and a similar clinical presentation. Because syphilis is not routinely tested for, awareness of this mimicry of herpes simplex virus encephalitis is important, considering the potential therapeutic implications.

Diagnosis, Differential↗
PubMed2001

Associations between stress, trait negative affect, acute immune reactivity, and antibody response to hepatitis B injection in healthy young adults.

Eighty-four healthy graduate participants were administered the standard course of 3 hepatitis B vaccinations. Five months after the first dose (shortly after the second injection), each participant completed psychosocial measures, and a blood sample was drawn for determination of hepatitis B surface antibody titer. After completion of the vaccination series, participants performed an acute stress protocol, consisting of a 30-min adaptation period and a 5-min evaluative speech task. Blood was drawn at the end of the resting and task periods for assessment of cellular immune measures. Lower antibody response, as assessed after the second hepatitis B injection, was predicted independently by (a) high trait negative affect and (b) diminished T-cell proliferation in response to PHA. These data provide evidence that trait negative affect and the magnitude of stress-induced suppression of immune function may have clinical significance.

Adult↗
PubMed2001

[The ubiquitin-proteasome system: the relationship between protein degradation and human diseases].

The ubiquitin-proteasome system is the major machinery in the cell for specific intracellular degradation. Degradation of a protein via the ubiquitin-proteasome pathway involves two successive steps: 1. Covalent attachment of multiple ubiquitin molecules to the substrate, and 2. Degradation of the tagged protein by the 26S proteasome complex. Via targeting of many substrates, the system regulates a broad array of basic cellular processes such as cell cycle, differentiation and signal transduction. Therefore, it is not surprising that aberrations in the system underlie the pathogenesis of many human diseases, among them malignancies, neurodegenerative diseases and many disorders of the immune and inflammatory response. In some pathologies the involvement of the system is direct, whereas in others the mechanistic linkage is less clear. It is expected that the ongoing extensive research in this area will shed light on the underlying pathogenetic mechanisms of the ubiquitin system-related diseases, and will lead to the development of mechanism-based therapeutic modalities.

Cysteine Endopeptidases↗
PubMed2000

Glycosylation-induced conformational modification positively regulates receptor-receptor association: a study with an aberrant epidermal growth factor receptor (EGFRvIII/DeltaEGFR) expressed in cancer cells.

The epidermal growth factor receptor (EGFR) is a multisited and multifunctional transmembrane glycoprotein with intrinsic tyrosine kinase activity. Upon ligand binding, the monomeric receptor undergoes dimerization resulting in kinase activation. The consequences of kinase stimulation are the phosphorylation of its own tyrosine residues (autophosphorylation) followed by association with and activation of signal transducers. Deregulation of signaling resulting from aberrant expression of the EGFR has been implicated in a number of neoplasms including breast, brain, and skin tumors. A mutant epidermal growth factor (EGF) receptor missing 267 amino acids from the exoplasmic domain is common in human glioblastomas. The truncated receptor (EGFRvIII/DeltaEGFR) lacks EGF binding activity; however, the kinase is constitutively active, and cells expressing the receptor are tumorigenic. Our studies revealed that the high kinase activity of the DeltaEGFR is due to self-dimerization, and contrary to earlier reports, the kinase activity per molecule of the dimeric DeltaEGFR is comparable to that of the EGF-stimulated wild-type receptor. Furthermore, the phosphorylation patterns of both receptors are similar as determined by interaction with a conformation-specific antibody and by phosphopeptide analysis. This eliminates the possibility that the defective down-regulation of the DeltaEGFR is due to its altered phosphorylation pattern as has been suggested previously. Interestingly, the receptor-receptor self-association is highly dependent on a conformation induced by N-linked glycosylation. We have identified four potential sites that might participate in self-dimerization; these sites are located in a domain that plays an important role in EGFR functioning.

Antibodies↗
PubMed2000

Bioengineered cardiac grafts: A new approach to repair the infarcted myocardium?

BACKGROUND: The myocardium is unable to regenerate because cardiomyocytes cannot replicate after injury. The heart is therefore an attractive target for tissue engineering to replace infarcted myocardium and enhance cardiac function. We tested the feasibility of bioengineering cardiac tissue within novel 3-dimensional (3D) scaffolds. METHODS AND RESULTS: We isolated and grew fetal cardiac cells within 3D porous alginate scaffolds. The cell constructs were cultured for 4 days to evaluate viability and morphology before implantation. Light microscopy revealed that within 2 to 3 days in culture, the dissociated cardiac cells form distinctive, multicellular contracting aggregates within the scaffold pores. Seven days after myocardial infarction, rats were randomized to biograft implantation (n=6) or sham-operation (n=6) into the myocardial scar. Echocardiography study was performed before and 65+/-5 days after implantation to assess left ventricular (LV) remodeling and function. Hearts were harvested 9 weeks after implantation. Visual examination of the biograft revealed intensive neovascularization from the neighboring coronary network. Histological examination revealed the presence of myofibers embedded in collagen fibers and a large number of blood vessels. The specimens showed almost complete disappearance of the scaffold and good integration into the host. Although control animals developed significant LV dilatation accompanied by progressive deterioration in LV contractility, in the biograft-treated rats, attenuation of LV dilatation and no change in LV contractility were observed. CONCLUSIONS: Alginate scaffolds provide a conducive environment to facilitate the 3D culturing of cardiac cells. After implantation into the infarcted myocardium, the biografts stimulated intense neovascularization and attenuated LV dilatation and failure in experimental rats compared with controls. This strategy can be used for regeneration and healing of the infarcted myocardium.

Alginates↗