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Biomedical subjects

E Cohen

Publications and source records attributed to E Cohen.

At least 163 records · Page 9Linked to original sources
PubMed1993

Human butyrylcholinesterase as a general prophylactic antidote for nerve agent toxicity. In vitro and in vivo quantitative characterization.

Butyrylcholinesterase purified from human plasma (HuBChE) was evaluated both in vitro and in vivo in mice and rats as a single prophylactic antidote against the lethal effects of highly toxic organophosphates (OP). The variation among the bimolecular rate constants for the inhibition of HuBChE by tabun, VX, sarin, and soman was 10-fold (0.47 to 5.12 x 10(7) M-1 min-1; pH 8.0, 26 degrees). The half-life of HuBChE in blood after its i.v. administration in mice and rats was 21 and 46 hr, respectively. The peak blood-enzyme level was obtained in both species approximately 9-13 hr following i.m. injection of HuBChE, and the fraction of the enzyme activity absorbed into the blood was 0.9 and 0.54 for rats and mice, respectively. The stoichiometry of the in vivo sequestration of the anti-cholinesterase toxicants was consistent with the HuBChE/OP ratio of the molar concentration required to inhibit 100% enzyme activity in vitro. Linear correlation was demonstrated between the blood level of HuBChE and the extent of protection conferred against the toxicity of nerve agents. Pretreatment with HuBChE alone was sufficient not only to increase survivability following exposure to multiple median lethal doses of a wide range of potent OPs, but also to alleviate manifestation of toxic symptoms in mice and rats without the need for additional post-exposure therapy. It appeared that in order to confer protection against lethality nerve agents had to be scavenged to a level below their median lethal dose LD50 within less than one blood circulation time. Since the high rate of sequestration of nerve agents by HuBChE is expected to underlie the activity of the scavenger in other species as well, a reliable extrapolation of its efficacy from experimental animals to humans can be made.

Animals↗
PubMed1993

Divergent age-associated patterns of high density lipoprotein cholesterol and its percentage in Jewish and Moslem Arab Israeli children and adolescents: the Petach Tikva Project.

We studied three groups of Israeli Jewish schoolchildren in and surrounding Petach Tikva, Israel, cross-sectionally, at ages 9-10, 13-14, and 16-18 years, and compared lipid and lipoprotein levels and age-associated lipoprotein patterns in the same age groups of boys and girls in neighboring Israeli Moslem Arab schools during 1986-1987. Moslem children displayed striking differences in the levels of lipids and age-associated patterns of lipoproteins compared with Jewish schoolchildren. The mean total cholesterol levels were lower in the Moslem children, in both sexes, in every age grouping. High density lipoprotein cholesterol (HDL-C) levels were significantly higher at age 16-18 in the Moslem boys than in the Jewish boys. While the Jewish boys displayed a previously reported "typical" pattern of lower HDL-C levels postpuberty compared with prepuberty, the Moslem boys had markedly higher mean HDL-C levels at age 16-18 compared with those at age 9-10. The Moslem girls also had higher HDL-C levels at age 16-18 than those observed in the age 9-10 group. Concomitantly higher HDL-C levels (HDL-C/total cholesterol (%)) were seen in the Moslem boys and girls, at age 16-18 compared with age 9-10, but were not observed in the Jewish children. The identification of an ethnic group in whom HDL-C appears to increase at or near puberty could provide opportunities to elucidate factors that may increase HDL-C in individuals or in populations.

Adolescent↗
PubMed1993

[Transfusion-related acute lung injury].

Transfusion related acute lung injury develops a few hours after transfusion of blood products and is characterized by fever, chills, severe dyspnea and bilateral crepitations. Chest x-ray reveals diffuse patchy infiltrates and blood gas analysis shows severe hypoxemia. It is caused by an immunologic reaction of antileukocyte antibodies which, in most cases, are transfused with blood products. We present 2 patients with this syndrome who responded to large doses of corticosteroids (1 g methyl prednisolone) and made full recoveries within 96 hours. Medical personnel should be aware of this unique subtype of the adult respiratory distress syndrome, which responds to corticosteroids and has a favorable prognosis.

Acute Disease↗
PubMed1993

Chitin synthesis and degradation as targets for pesticide action.

Various pesticides are being used to destabilize, perturb, or inhibit crucial biochemical and physiological targets related to metabolism, growth, development, nervous communication, or behavior in pestiferous organisms. Chitin is an eukaryotic extracellular aminosugar biopolymer, massively produced by most fungal systems and by invertebrates, notably arthropods. Being an integral supportive component in fungal cell wall, insect cuticle, and nematode egg shell, chitin has been considered as a selective target for pesticide action. Throughout the elaborate processes of chitin formation and deposition, only the polymerization events associated with the cell membrane compartment are so far available for chemical interference. Currently, the actinomycetes-derived nucleoside peptide fungicides such as the polyoxins and the insecticidal benzoylaryl ureas have reached commercial pesticide status. The polyoxins and other structurally-related antibiotics like nikkomycins are strong competitive inhibitors of the polymerizing enzyme chitin synthase. The exact biochemical lesion inflicted by the benzoylaryl ureas is still elusive, but a post-polymerization event, such as translocation of chitin chains across the cell membrane, is suggested. Hydrolytic degradation of the chitin polymer is essential for hyphal growth, branching, and septum formation in fungal systems as well as for the normal molting of arthropods. Recently, insect chitinase activity was strongly and specifically suppressed by allosamidin, an actimomycetes-derived metabolite. In part, the defense mechanism in plants against invasion of pathogens is associated with induced chitinases. Chitin, chitosan, and their oligomers are able to act as elicitors which induce enhanced levels of chitinases in various plants. Lectins which bind to N-acetyl-D-glucosamine strongly interfere with fungal and insect chitin synthases. Plant lectins with similar properties may be involved in plant-pathogen interaction inter alia by suppressing fungal invasion.

Animals↗
PubMed1993

Effects of 60 Hz electric and magnetic fields on the development of the rat cerebellum.

The effects of extremely low frequency (ELF) electromagnetic (EM) fields on the maturation of the rat cerebellum were studied. Newborn rats were exposed to 60 Hz electric and magnetic fields under three different combinations in a specially constructed apparatus. The pups were irradiated for 7-8 h daily, with a 30-min interruption for nursing. Pups were kept with their mothers for the remainder of the time. After approximately 1, 2, or 3 weeks of exposure, the pups were killed. Control pups were sham exposed. The somatic growth of the irradiated rats did not show any significant difference from sham-exposed controls. At 1 kV/m and 10 gauss exposure, there was a small but statistically significant decrease in cerebellar mass. In rats exposed at 1 kV/m and 10 gauss, DNA and RNA levels were significantly higher than those in sham-exposed controls at 6 and 13 days of age, but at 20 days, these two biochemical constituents were similar in both groups of rats. The ELF-EM treatment had no effect on protein and cerebroside concentrations. In terms of age effects, DNA and RNA exhibited increases from 6 to 13 days of age, and declined from 13 to 20 days. Protein and cerebroside levels exhibited increases during the 6-20-day periods. In rats exposed at 100 kV/m and 1 gauss, the DNA levels were initially less than those of sham-exposed controls at 8 days of age, reached approximately the same levels at 14 days, and then were higher than those of controls at 22 days. There was, therefore, a significant ELF-EM effect as well as a significant interaction between age and ELF-EM exposure. In terms of age effects, DNA levels for both control and exposed animals increased from 8 to 14 days. From 14 to 22 days, DNA levels of exposed rats continued to increase while those of the controls decreased. This age effect was significant. RNA levels in both groups of animals showed increases from 8 to 14 days of age, but the increase was less for the irradiated animals than for the controls. From days 14 to 22, RNA levels for both groups showed a reduction, but the decrease was greater in the irradiated than in control rats. ELF-EM treatment significantly reduced protein levels at 8 days of age, but at 14 to 22 days, protein levels of exposed rats were higher than those of controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Effects of 60 Hz electric and magnetic fields on maturation of the rat neopallium.

This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception, after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham-exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF-EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA, RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF-EM fields caused minimal or no changes in somatic growth and cerebral development of the rat.

Animals↗
PubMed1993

Describing the homeless mentally ill: cluster analysis results.

Presented descriptive data on a group of homeless, mentally ill individuals (N = 108) served by a two-site demonstration project, funded by NIMH. Comparing results with those from other studies of this population produced some differences and some similarities. Cluster analysis techniques were applied to the data, producing a 4-group solution. Data validating the cluster solution are presented. It is suggested that the cluster results provide a more meaningful and useful method of understanding the descriptive data. Results suggest that while the population of individuals served as homeless and mentally ill is quite heterogeneous, many have well-developed functioning skills--only one cluster, making up 35.2% of the sample, fits the stereotype of the aggressive, psychotic individual with skill deficits in many areas. Further discussion is presented concerning the implications of the cluster analysis results for demonstrating contextual effects and thus better interpreting research results from other studies and assisting in future services planning.

Adult↗
PubMed1993

Transoesophageal echocardiography and the intraoperative diagnosis of left atrial invasion by carcinoid tumour.

A 41-yr-old woman with pulmonary carcinoid tumour presented for thoracotomy and lung resection. However, intraoperative transoesophageal echocardiography (TEE) revealed that the tumour had invaded the left atrium, and the planned resection was aborted to allow resection under cardiopulmonary bypass at a later date. Although the incidence of cardiac involvement by lung cancer at the time of pulmonary resection is unknown, transoesophageal echocardiography can be useful in identifying the extension of hilar lung tumours. This should preferentially be done preoperatively, but can be done intraoperatively as described in this case report.

Adult↗
PubMed1993

Prevention of soman-induced cognitive deficits by pretreatment with human butyrylcholinesterase in rats.

This study examined the ability of pretreatment with human serum butyrylcholinesterase (HuBChE) to prevent soman-induced cognitive impairments. Behavioral testing was carried out using the Morris water maze task evaluating learning, memory, and reversal learning processes. Pretreatment with HuBChE significantly prevented the memory and reversal learning impairments induced by soman. A small deficiency in performance was observed only during part of the learning period in HuBChE-treated rats after administration of soman. Results support the contention that pretreatment alone with HuBChE is sufficient to increase survival and to prevent impairment in cognitive functioning following exposure to soman.

Animals↗
PubMed1993

Intrathecal morphine during thoracotomy, Part I: Effect on intraoperative enflurane requirements.

The ability of intrathecal morphine to reduce the anesthetic requirements during thoracotomy was investigated. Twenty-four patients scheduled for thoracic surgery were studied. Anesthesia was induced with thiamylal sodium, 4 mg/kg, fentanyl, 100 micrograms, and 100 mg of succinylcholine. Prior to skin incision, 12 patients received intrathecal injection of 12 micrograms/kg of preservative-free morphine sulfate (ITM), while the remaining 12 patients served as controls. The ITM was given undiluted at the L3-4 or L4-5 level. Anesthesia was maintained solely with enflurane, titrated to keep mean arterial pressure within 15% of the preoperative values. Vecuronium was given as required for relaxation. No additional narcotics were administered. Throughout the procedure, end-tidal (ET) enflurane concentration was recorded at 15-minute intervals from the mass spectrometer (Perkin Elmer). The intraoperative mean ET concentration of enflurane was significantly reduced in the ITM group beginning 1 hour after the injection (1.19 +/- .45% in the control group versus 0.73 +/- 0.08% in the ITM group). The enflurane requirements, expressed as percent end-tidal enflurane/hour, were significantly less in the ITM group for the duration of the procedure (0.8 +/- .17 v 1.08 +/- .22, respectively). In conclusion, when administered prior to skin incision for post-thoracotomy pain control, intrathecal morphine reduces intraoperative enflurane requirements.

Aged↗
PubMed1993

Intrathecal morphine during thoracotomy, Part II: Effect on postoperative meperidine requirements and pulmonary function tests.

The ability of intrathecal morphine (ITM) to reduce post-thoracotomy pain and meperidine requirements was investigated. Thirty adult patients scheduled for thoracic surgery were studied. Following induction with thiamylal sodium and succinylcholine, anesthesia was maintained with 100 micrograms of fentanyl, vecuronium, and enflurane. Prior to skin incision, 16 patients received intrathecal morphine, 12 micrograms/kg, injected at the L3-4 or L4-5 level. The other 14 patients were controls. Postoperatively, patients were evaluated for pain scores and the total doses of meperidine required over 24 hours. The patients in the ITM group required significantly less meperidine compared to the control group (59 +/- 68 v 167 +/- 97 mg, respectively) and had lower pain scores (1.4 +/- 1.1 v 2.4 +/- 0.9 mg, respectively). There were no serious side effects attributable to ITM. It is concluded that ITM is an effective adjunctive treatment for control of post-thoracotomy pain.

Aged↗