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Biomedical subjects

J Cohen

Publications and source records attributed to J Cohen.

At least 1,081 records · Page 60Linked to original sources
PubMed1989

The effects of lymphokines and monokines on human sperm fertilizing ability in the zona-free hamster egg penetration test.

Antisperm cell-mediated immunity has been associated with infertility in men and women. The purpose of this study was to determine whether the products of activated lymphocytes and macrophages (lymphokines and monokines) affect the fertilizing ability of human spermatozoa in the zona-free hamster egg penetration test. Of a panel of six different purified cytokines tested, the lymphokine gamma-interferon and the monokine tumor necrosis factor significantly affected the ability of human sperm to penetrate hamster eggs. An inhibitory effect was observed when motile sperm were harvested for use in the assay by a swim-up technique after overnight incubation in low amounts of these cytokines and also when the factors were added to the cultures at the time sperm were introduced to the eggs. These data contribute further evidence that soluble factors produced by activated lymphocytes and macrophages in reproductive tissues could be significant mediators of immunologic infertility.

Animals↗
PubMed1989

Nucleotide sequence of bovine rotavirus gene 1 and expression of the gene product in baculovirus.

The nucleotide sequence of the gene that encodes for the structural viral protein VP1 of bovine rotavirus (RF strain) has been determined. The sequence data indicate that segment 1 contains 3302 bp and is A + T rich (65.3%). The positive strand of segment 1 contains a single open reading frame that extends 1088 codons and possesses 5'- and 3'-terminal untranslated regions of 18 and 20 bp, respectively. The first AUG conforms to the Kozak consensus sequence and if utilized, would yield a protein having a calculated molecular weight of 124,847, very close to the apparent molecular weight of VP1 (M.W. 125,000). The deduced amino acid sequence presents significant similarities with RNA-dependent RNA polymerase of several RNA viruses. VP1 was also synthesized in baculovirus using two transfer vecors: pAC461 and pVL941. Following infection of Sf9 cells with a recombinant baculovirus, a full-length nonfusion protein was synthesised which shares properties with authentic VP1 made in monkey kidney cells. The level of VP1 synthesis was about 10-fold higher when the baculovirus recombinant was derived from the pVL941 transfer vector. In that case, VP1 was expressed in yields approximately equivalent to 10% of the cellular protein. The recombinant protein was immunoprecipitated by hyperimmune serum raised against purified rotavirus. It also was immunogenic; a hyperimmune serum made in guinea pigs reacted with VP1 using immunoprecipitation and Western blot. This serum did not possess neutralization activity.

Amino Acid Sequence↗
PubMed1989

Magnetic resonance imaging determination of myometrial invasion in endometrial carcinoma.

Fifteen patients with FIGO stage I biopsy confirmed endometrial adenocarcinoma underwent preoperative pelvic magnetic resonance imaging (MRI) to evaluate the presence and depth of myometrial invasion. Imaging was performed with a Diasonics superconducting imaging system operating at 0.35 T (15 MHz); multislice multi-spin-echo pulse sequences were used exclusively, with 5-mm contiguous sections. All patients then received primary therapy consisting of abdominal hysterectomy and bilateral salpingo-oophorectomy. Imaging findings were then compared with the uterine specimen histopathology. MRI was accurate in predicting the presence or absence of invasion in 13 of 15 cases (87%) and was able to discriminate superficial from deep invasion in 9 of 11 cases (82%). Based on our findings, we conclude that MRI appears to be an excellent technique for determining myometrial invasion, and that it may play a significant role in the preoperative planning of a thorough search for lymphatic spread in those patients considered to be at high risk by virtue of myometrial invasion.

Adult↗
PubMed1989

A plaque hybridization assay for rotaviruses.

A plaque hybridization assay was adapted to rotavirus. In this test cDNA or oligonucleotide probes were used to discriminate between plaques originating from virus carrying genes of bovine and simian origin. Only mRNAs present in infected cells were detected as demonstrated by using oligonucleotides corresponding to both strands. This assay can be used to screen reassortants or mutants of rotaviruses.

Animals↗
PubMed1989

Comparative effects of kainic, quisqualic, and ibotenic acids on phenylethanolamine-N-methyltransferase-containing cells of rat retina.

Phenylethanolamine-N-methyltransferase (PNMT) activity is located in a subpopulation of amacrine cells in the inner nuclear layer of the rat retina. Kainic, quisqualic, and ibotenic acids, all of which are analogues of glutamic acid, were injected intravitreally to the right and saline to the contralateral left eyes of adult male rats in order to determine the effect of these agents upon retinal PNMT activity. Animals were sacrificed 1 week later for tissue removal. The effect of these agents was measured by radiometric assay for PNMT. The fall in PNMT activity was used to measure the sensitivity of the PNMT-containing cells to these agents. Kainic acid was the most potent, producing the greatest reduction in PNMT activity in the smallest doses. Quisqualic acid was intermediate in potency to that of kainic and ibotenic acids. Ibotenic acid reduced PNMT activity only in extremely high doses. The PNMT-containing cells are sensitive to the toxic actions of kainic and quisqualic acids, but relatively insensitive to the actions of ibotenic acid.

Animals↗
PubMed1989

Partial zona dissection of the human oocyte: a nontraumatic method using micromanipulation to assist zona pellucida penetration.

Partial zona dissection (PZD), a method using mechanical force to open the human zona pellucida, and zona drilling, which uses acidic Tyrode's (AT) medium, were compared in 1-day-old oocytes prior to reinsemination. The incidences of monospermy and polyspermy were 13/54 (24%) and 14/54 (26%) following PZD and 6/46 (13%) and 8/46 (17%) following the use of AT medium. This compared favorably with conventional reinsemination: 15/161 (9%) monospermy and 4/161 (3%) polyspermy. Three of the 27 PZD embryos became blastocysts, while none of the AT-exposed embryos developed satisfactorily. Eleven male-factor couples had some of their oocytes randomly treated with PZD prior to insemination; each of the patients had non-micromanipulated control oocytes. Monospermic fertilization and cleavage (23/34; 68%) doubled (P less than 0.05) when PZD was compared with the control oocytes (10/30; 33%). Replacing two PZD and a single control embryo in two patients resulted in twin pregnancies. A third twin pregnancy was established following replacement of only micromanipulated embryos.

Cell Division↗
PubMed1989

Videocinematography of fresh and cryopreserved embryos: a retrospective analysis of embryonic morphology and implantation.

Eleven morphologic criteria were studied from videotapes of 323 fresh and 103 thawed embryos. The proportion of thawed embryos (30/39; 77%) with more than one abnormality was (P = 0.03) higher than that of fresh embryos (5/13; 38%), despite similar implantation rates (18% and 15%, respectively). The best predictor of thawed embryo implantation was cell-cell adherence: when scored "positive," 11 of 17 women (65%) became pregnant, whereas none became pregnant (0/15; P = 0.0002) when blastomeres did not adhere. The total number of abnormalities for thawed embryos was an important prognostic. An increased percentage variation of zona pellucida thickness was the most important prognostic for fresh embryos. When the "best" embryo had a zona pellucida that varied more than 25%, 24 of 60 (40%) resulted in pregnancy; pregnancies were not induced (0/21) when the "best" embryo had less than 10% variation (P = 0.0003).

Blastomeres↗
PubMed1989

Embryonic development after microsurgical repair of polyspermic human zygotes.

Correction of polyspermy through pronucleus extraction in the absence of membrane relaxants was applied to 25 polyspermic human zygotes. Nine zygotes survived the procedure, and seven cleaved normally (two of which were fixed for chromosome analysis); two proceeded to compact and one cavitated. Eighteen of the polyspermic zygotes (14 with three pronuclei and 4 with four pronuclei) were obtained from zona pellucida-intact oocytes, and seven (1 five-pronucleate 3 four-pronucleate, and 3 three-pronucleate) from previously zona-drilled oocytes. Survival and cleavage occurred in all groups except in four- and five-pronucleate zona-drilled zygotes. Criteria used to identify male pronuclei were (1) pronucleus-associated sperm tails, (2) increased pronucleus size, and (3) greater distance (relative to female pronuclei) from the second polar body. Sperm tails were never seen and pronucleus size usually was identical. Therefore, the third criterion was used, although its reliability should be further evaluated. Until complete pronucleus removal techniques and reliable pronucleus selection criteria are perfected, embryo replacement after polyspermy correction could result in aneuploidy and molar pregnancy.

Embryonic and Fetal Development↗
PubMed1989

Coculture of human zygotes on fetal bovine uterine fibroblasts: embryonic morphology and implantation.

Zygotes from in vitro fertilization patients (n = 116) were randomly allocated to culture in either conventional plastic petri dishes or coculture on a monolayer of fetal bovine uterine fibroblasts. Embryos (n = 288) remained 26 to 32 hours in these culture systems. Video tape recording for later morphological analysis (11 parameters) was performed on 117 conventionally cultured and 104 cocultured embryos, shortly before replacement, by an independent observer, unaware of the culture conditions for each embryo. A significantly greater number of cocultured embryos (52%) had "good" morphology (zero or only one abnormal characteristic) as compared with conventionally cultured embryos (30%). The most outstanding morphological characteristic of cocultured embryos was the expanded appearance of their blastomeres. The incidence of implantation per embryo increased from 13% to 19% when the coculture rather than conventional culture system was used, and the incidence of ongoing pregnancy per patient after coculture doubled to 35%.

Animals↗
PubMed1989

Appropriate technology in primary health care. Evolution and meaning of WHO's concept.

This article examines the meaning of appropriate technology in the World Health Organization's comprehensive definition of primary care. The author concludes that broad-ranging aspects of health maintenance, such as public health, personal lifestyles, and scientific research, as well as traditional diagnostic and therapeutic practices, need to be subjected to clear and careful scrutiny. It is vital that the results of these technology assessment studies be disseminated as widely as possible to both health care professionals and the public.

Primary Health Care↗
PubMed1989

Azido glycols: potent, low molecular weight renin inhibitors containing an unusual post scissile site residue.

Azidomethyl-substituted 1,2- and 1,3-diols were prepared from Boc-cyclohexylalanal and evaluated as transition state analogue renin inhibitors, leading to the development of a small (MW less than 600), nanomolar inhibitor. Remarkable aqueous solubility enhancement followed the incorporation of an N-terminal urea functionality. Evaluation of selected compounds both in vivo and in vitro demonstrated that while transport across the intestine occurred upon id administration, extensive liver extraction resulted in low systemic levels.

Animals↗
PubMed1989

Comparative evaluation of caffeine and theophylline for weaning premature infants from the ventilator.

Expedient weaning of infants from the respirator minimizes the risk of complications associated with assisted ventilation. Since theophylline and caffeine decrease apnea and enhance respiratory effort, we conducted a blinded, randomized comparative evaluation of each drug to determine extubation time and incidence of reintubation. Forty-five clinically stable premature infants receiving mechanical ventilation on minimal settings randomly were assigned to receive either theophylline (n = 23) or caffeine (n = 22) at least 1 day before and 5 days after extubation. From study entry to extubation, the mean number of days was 2.7 for both theophylline- and caffeine-treated infants. Three theophylline- and three caffeine-treated infants developed respiratory failure necessitating reintubation (NS). These findings indicate that for premature infants on minimal respiratory settings, the duration of intubation and the incidence of reintubation after treatment with theophylline or caffeine were similar.

Caffeine↗
PubMed1989

Socioeconomic concerns in vascular surgery: a survey of the role of age, resource consumption, and outcome in treatment cost.

Surgical hospital payment issues and socioeconomic concerns are likely to attract more attention in the future, especially regarding access and the quality of surgical care. We analyzed all peripheral vascular surgical admissions (n = 1240) by age treated at the Long Island Jewish Medical Center from 1985 to 1987. Hospital cost and length of stay per patient increased with age, as did losses under diagnostic related group (DRG) prospective hospital payment. Hospital cost by hospital service showed considerable variation by age category; outliers, mortality, and the number of diagnoses and procedures generally rose with age. Use of hospital resources, such as emergency or surgical intensive care unit admission, or the need for blood or plasma products was high in general for patients undergoing peripheral vascular surgery. This study demonstrates a number of findings regarding the socioeconomic factors for hospitalized patients undergoing peripheral vascular surgery. Surgical health policy analysis of this specialty vis-a-vis current changes proposed to the federal medicare DRG system in the U.S. Congress and Health Care Financing Administration suggests a relatively greater impact on the specialty of peripheral vascular surgery demonstrated in this study by the use of higher resources of the same.

Adolescent↗
PubMed1989

Invasive aspergillosis: clinical and pathological features of a new animal model.

A new animal model of invasive aspergillosis is described in which female New Zealand White rabbits were immunosuppressed with corticosteroids and cyclophosphamide and were given an intratracheal inoculation of 4 x 10(4) conidia of Aspergillus fumigatus. Thirteen of 15 animals survived during a 10-day-period of observation. Most had clinical signs of a respiratory infection (dyspnoea) and at autopsy there was macroscopic and microscopic evidence of invasive pulmonary aspergillosis. Six control animals (infected but not immunosuppressed) showed no such signs. The extent of hyphal invasion was assessed histologically and quantified by calculating the number of colony forming units (c.f.u.) g-1 of tissue: in the experimental group the mean c.f.u. value for the lungs was 1.25 x 10(3) compared to 73.3 c.f.u. g-1 of lung for the control group (P = 0.003). The infection was also quantified by a whole lung chitin assay: in the experimental group the mean chitin content (expressed as a glucosamine equivalent) was 3.05 micrograms g-1 lung tissue compared to a 0.53 micrograms g-1 lung tissue for the control group (P = 0.01). We conclude that this model of invasive aspergillosis in rabbits reflects closely the pathological features of the disease in man and that it may prove useful for studies of the pathogenesis and the treatment of invasive aspergillosis.

Animals↗
PubMed1989

Cytogenetic analysis and developmental capacity of normal and abnormal embryos after IVF.

Chromosome abnormalities represent the major cause of pre- and post-implantation embryo wastage. Indeed, 29% of embryos produced by in-vitro fertilization have an abnormal karyotype. Parthenogenesis (1.6% of the cases) and triploidy (6.4%) are the only abnormalities detectable 17 h after insemination. A total of 23% of activated oocytes with a single pronucleus (1 PN) and 18% of fertilized eggs with three pronuclei (three PN) remained uncleaved, compared with 4% for diploid eggs. The rate of cleavage for parthenogenes is not different from normal eggs. On the contrary, we observed that 29% of three PN-eggs reached the 5- to 8-cell stage 42 h after insemination when compared to 15% for diploids mainly due to a direct division of 56% of three PN-eggs in three cells. A model of development for triploid eggs is proposed, taking into account physiological and cytogenetic observations. The quality of embryos expressed in terms of morphology did not show any difference between embryos proceeding from parthenogenes or diploid eggs. On the contrary, the rate of fragmentation is decreased for triploid (3%) compared with diploid (13%) or activated (17%) embryos. Embryos resulting from one, two, three or four pronucleate ova display different developmental capacities during 5 days' culture in vitro.

Chromosome Aberrations↗
PubMed1989

Partial zona dissection of human oocytes when failure of zona pellucida penetration is anticipated.

Partial zona dissection (PZD) of human oocytes facilitates sperm penetration through mechanically made holes in the zona pellucida. Only 1 of 69 eggs was damaged when sucrose was used to shrink the ooplasm during micromanipulation. The fertilization rate of micromanipulated oocytes in 18 couples with male factor infertility was 68% (34/50), which compared favourably with insemination of non-micromanipulated controls (21/45, 47%). PZD was advantageous in oligozoospermic patients, but not in cases of asthenozoospermia, combined semen problems or immunological infertility. Three twin and two singleton pregnancies resulted following replacement of 23 micromanipulated and eight control embryos in 14 patients. No differences in embryo morphology and development rates were found between the micromanipulated and control groups. The incidence of polyspermy in couples with abnormal semen analyses was relatively low (less than 20%) possibly due to partial activation of the oocytes following exposure to sucrose. Polyspermy was high (57%) in normozoospermic patients with either immunological infertility (n = 3) or failure of fertilization in previous cycles (n = 4). In the three immunological patients, nine of 11 hyaluronidase and sucrose-exposed control embryos fertilized and six implanted, possibly indicating that cumulus and corona cells are contributing factors inhibiting fertilization in such cases.

Embryo Transfer↗