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Biomedical subjects

J Cohen

Publications and source records attributed to J Cohen.

At least 811 records · Page 45Linked to original sources
PubMed1993

Gastroesophageal reflux and laryngeal disease.

OBJECTIVE: We wanted to determine if surgical correction of gastroesophageal reflux disease (GERD) would affect inflammatory laryngeal lesions in a select group of patients with known GERD and chronic inflammatory laryngeal lesions. DESIGN: Patients with persistent inflammatory lesions in the larynx were referred for workup of GERD when these lesions were not associated with smoking or drinking or when cessation of smoking failed to ameliorate these lesions during a minimum period of 6 months. Twenty-four-hour pH monitoring was used to confirm GERD in 10 patients, while two patients had GERD confirmed radiologically, and one patient had typical symptoms of esophagitis and incompetent lower esophageal sphincter. Thus, 13 patients with chronic laryngeal inflammation persistent after cessation of smoking had concomitant GERD. These patients were all treated with Nissen fundoplication for GERD. SETTING: Patients with chronic laryngitis were referred to an otolaryngologist at a tertiary medical center. PATIENTS: Patients were consecutively selected as they presented with chronic persistent laryngeal lesions and were found to have GERD. INTERVENTIONS: Surgical correction of GERD with Nissen fundoplication. MAIN OUTCOME MEASURES: Status of the larynx was assessed at 3-month intervals with fiberoptic laryngoscopy and symptoms (ie, hoarseness, sore throat) were evaluated. RESULTS: Laryngeal inflammatory lesions and voice changes (hoarseness and sore throat) promptly resolved in eight (73%) of 11 patients. To date, these improvements have continued after a mean follow-up of 11 months. CONCLUSIONS: Correction of GERD in a selected subset of patients with laryngeal inflammatory lesions ameliorates these lesions.

Chronic Disease↗
PubMed1993

Calmodulin is essential for assembling links necessary for exocytotic membrane fusion in Paramecium.

Calmodulin has long been suspected to be involved in calcium-regulated exocytosis but its precise site(s) of action has not yet been identified. In Paramecium, a genetic approach to the problem is possible as in vivo-selected mutations in the calmodulin gene that prevent the activation of some channels have been characterized. Three of these calmodulin mutants were examined for exocytotic capacity and the mutant cam1 was found to be defective for exocytosis at 35 degrees C. The loss of exocytotic capacity in cam1 cells can be restored by transformation with the wild-type calmodulin gene, demonstrating that its exocytotic lesion is indeed due to the mutation in the calmodulin gene. The cam1 mutant displays abnormal exocytotic sites at the non-permissive temperature: it lacks the links ('rosettes' of intramembranous particles in the plasma membrane and the fibrous 'connecting material') which normally connect plasma and trichocyst membranes. Upon shift of cam1 cells from the permissive to a non-permissive temperature, performed sites remain functional. These results demonstrate that calmodulin is necessary for the assembly of these links at the exocytotic site. These results do not, however, exclude the possibility of calmodulin also being involved in Ca(2+)-dependent steps of the stimulus-exocytosis coupling.

Animals↗
PubMed1993

Analysis of partial variance (APV) as a statistical approach to control day to day variation in immune assays.

The considerable day to day variability in some immunologic assays can obscure relationships among measures of interest and thereby complicate interpretation of findings when effect sizes are modest. Analysis of partial variance (APV) is a technique that utilizes data obtained from controls run in the laboratory on the day of each assay to control for day to day variance statistically. The application of this technique to permit detection of otherwise obscured effects for both larger and smaller samples is exemplified utilizing data from two studies in which subjects were assessed on multiple different dates. These included a study of the association of depression with in vitro immune measures in 296 adolescents and a longitudinal study of 20 spouses of patients admitted to a cardiac intensive care unit studied together with 20 matched controls. APV was most useful in analyses of mitogen-induced lymphocyte proliferation assays, which had considerable day to day variability. In general, multivariate studies with functional immune measures may benefit most from application of this technique.

Adolescent↗
PubMed1993

Plasmanate as a medium supplement for in vitro fertilization.

PURPOSE: The purpose of this study was to evaluate the use of Plasmanate, a protein preparation containing human serum albumin and mixed globulins to autologous preovulatory maternal serum, as an in vitro fertilization (IVF) medium supplement. Plasmanate was used most often in cases involving unexplained infertility, sperm antibodies, and endometriosis or when serum was unavailable. RESULTS: In a retrospective analysis of 1019 consecutive IVF cycles, Plasmanate was used as the protein supplement to the fertilization medium in 28.6% and maternal serum was used in 71.4% of the attempts. Attempting to eliminate the effects of different medium lots and laboratory conditions, 450 matched patient cycles were compared using the two protein supplements. Finally, the effects of Plasmanate versus maternal serum were compared in prospective randomized trial on patients diagnosed with tubal infertility who were attempting IVF for the first time. The clinical pregnancy rate was 34% for the Plasmanate group versus 24% for those using maternal serum in the retrospective investigation. However, this trend was reversed in the prospective trial. CONCLUSION: Although further investigation is necessary, it appears that Plasmanate is an appropriate protein substitute in patient cases where serum is absent or unsuitable.

Adult↗
PubMed1993

A fast and efficient method for simultaneous X and Y in situ hybridization of human blastomeres.

PURPOSE: To use a 6-hr fluorescence in situ hybridization (FISH) procedure involving fluorochrome-labeled probes to determine the gender of blastomeres from arrested biopsied human embryos. RESULTS: Simultaneous detection of X and Y chromosomes was performed on 68 blastomeres with this technique. The FISH efficiency for gender determination was 95.5% (65/68). In addition, rehybridization with chromosome 8-specific probes was performed to determine the ploidy of blastomeres with more than two sex chromosomes. CONCLUSION: This technique offers an alternative to polymerase chain reaction for the preimplantation diagnosis of X-linked diseases and can also be used for ploidy assessment.

Biopsy↗
PubMed1993

Origin of single pronucleated human zygotes.

PURPOSE: Diploidy in embryos developing from single pronucleated zygotes can occur following parthenogenetic activation or by asynchronous inflation of pronuclei following fertilization. To distinguish between these two mechanisms, sexing was performed. RESULTS: The presence of a Y chromosome in the embryo was considered proof that fertilization had occurred. Twenty-one dividing embryos originating from single pronucleated zygotes were analyzed using the polymerase chain reaction or fluorescence in situ hybridization. In total, 43% (9/21) of the embryos showed Y chromosomes. CONCLUSION: It can be extrapolated that more than 80% of them originated from fertilized eggs.

Cell Nucleus↗
PubMed1993

Expression of two bovine rotavirus non-structural proteins (NSP2, NSP3) in the baculovirus system and production of monoclonal antibodies directed against the expressed proteins.

Studies on rotavirus non-structural proteins have been hampered in the past by difficulties in obtaining monospecific reagents. To make such reagents available, we have expressed in the baculovirus system NSP2 and NSP3 (formerly called NS35 and NS34, respectively) of the bovine rotavirus RF and produced hybridomas against these proteins. Full-length DNA copies of RNA segments 7 (coding for NSP3) and 8 (coding for NSP2) of the virus strain RF were cloned and sequenced. Each cDNA was inserted in the transfer vector pVL941 and used to transfect Spodoptera frugiperda cells (Sf9). Recombinant baculoviruses encoding these proteins were obtained. Infection of Sf9 cells with these recombinant viruses resulted in a high level of expression of NSP2 and NSP3 (range of 1 microgram per 10(6) cells). Monoclonal antibodies (MAbs) were elicited by immunization of BALB/c mice with adjuvented, unpurified recombinant proteins in the rear foot pads. Fusion was performed using lymphocytes from popliteal lymph nodes with SP2/O-Ag14 myeloma line. Screening was by differential indirect immunofluorescent staining on monolayers of Sf9 cells infected with each recombinant virus. Two MAbs proved to be reactive against NSP3 and a single one against NSP2. They showed high specificity by immunofluorescence, immunoprecipitation and Western blot. The isotype of these MAbs was IgG1. Oligomeric forms of NSP3 and NSP2 proteins were detected and the existence of intra-chain disulfide bridge in NSP2 protein was suggested. The levels of synthesis and cellular localization of NSP3 and NSP2 proteins were different as shown by immunoprecipitation and immunofluorescence.

Animals↗
PubMed1993

In vitro reconstitution of rotavirus transcriptional activity using viral cores and recombinant baculovirus expressed VP6.

Purified baculovirus-expressed group A rotavirus VP6 polypeptide was shown to be active in the recovery of the transcriptase activity associated with the reconstitution of the single-shelled rotavirus particle. Recombinant VP6 polypeptide was able to restore the transcriptional activity in purified viral cores from both SA-11 and RF rotavirus strains. Recombinant group C VP 6 (Cowden strain) is capable of binding as a trimer to group A viral core particles but unable to restore the transcriptase activity, suggesting that the binding of the polypeptide to cores is not the only requirement to restore the transcriptase activity. The VP 6 group A polypeptide was shown to bind as a monomer to viral cores, indicating that trimerization of VP 6 may be not required for reconstitution of the polymerase activity.

Antigens, Viral↗
PubMed1993

Sequence analysis of three non structural proteins of a porcine group C (Cowden strain) rotavirus.

Sequences of three gene products of a group C (Cowden strain) rotavirus are presented and compared with the sequences of the corresponding group A (SA11) proteins. The degree of similarity for gene 7, 9, and 10 is respectively 34%, 58%, and 45%. Comparison of these 2 viruses allowed to identify several regions well conserved. In the protein coded by Cowden segment 7 (NS 53) only a short cystein and histidine rich region, presenting the zinc finger consensus motif, is common to group A (segment 5) and group C sequences. Conversely the protein coded by segment 9 (NS 35) presented marked homology with group A NS 35. The protein coded by segment 10 (NS 26) is serine rich and presents an accumulation of charged residues near the carboxy terminus, like group A counterpart. This genomic segment presented a single large open reading frame, that contrasts with the group A counterpart for which a second out of phase ORF is used in rotavirus infected MA 104 cells.

Amino Acid Sequence↗
PubMed1993

Extraction site healing in rats. A radiologic densitometric study.

The present study uses a simple, objective method to radiographically evaluate the changes that occur during socket healing in rats. Mandibular left first molars were extracted in 35 Wistar rats, which were then sacrificed at 0, 7, 14, 21, 28, 45, and 60 days after surgery. Mandibles were removed, placed on an ANSI size 2 film, and exposed with an aluminum step-wedge, 0.5 to 3.0 mm. Socket density was measured with a digital densitometer and related to the equivalent density of aluminum. Increased density of the image of the apical and crestal areas of the socket was observed on day 7. Maximum density was reached by day 28 in the apical area; in the crestal area, density increased at a slower rate. The density changes found in the present study agree with the known histologic reports of socket healing in rats. Densitometric evaluation of extraction socket healing, using a step-wedge with 0.5 mm increments, is a useful and reliable tool to objectively assess bone formation and mineralization.

Aluminum↗
PubMed1993

Mapping schizophrenic negative symptoms onto measures of the patient's speech: set correlational analysis.

We describe a system designed to assess the speech behaviors that inform clinicians about their patients' negative symptoms. Measures are formed into scales to reflect the patient's Pausing, Speech Rate, and Dyadic Interaction with the interviewer. Using set correlation, we examined the associations between the acoustic scales and the clinician's ratings of Flat Affect, Alogia, and Asociality. Over half of the multivariance in the clinical scales was accounted for by the acoustic scales. Unique isomorphisms between the acoustic and rating scales were found for: Dyadic Interaction with Flat Affect; Pause Production with Alogia; and Rate with Asociality.

Adult↗
PubMed1993

Microinjection of FITC-dextran into mouse blastomeres to assess topical effects of zona photoablation.

The objective of the current experiments was to investigate whether all or only some blastomeres from precompacted mouse embryos were affected by zona photoablation. The microbeam of xenon chloride excimer laser (308 nm) was guided through an inverted microscope (non-contact system). Topical effects of lasing were determined by microinjection of a vital fluorescent dye of high molecular weight (fluorescein isothiocyanate [FITC] dextran) into the cell immediately adjacent to the site of zona photoablation. This dye is only passed onto daughter blastomeres and therefore allows study of specific cell lines. Embryonic growth was assessed following cell separation at the morula and blastocyst stage. Four-cell embryos treated with the laser had significantly fewer cells 12 h after zona photoablation than control embryos. A similar effect was noted after 24 h between dye injected embryos and those injected and lased simultaneously, indicating potential toxic effects of the laser treatment on the embryo. Effects on the blastomere closest to the site of ablation were evaluated by calculating the ratio of dyed cells to the total number of cells at specific time intervals. The ratios were similar in the dye and laser+dye groups of treated 4-cell embryos 36 h after treatment (0.22 and 0.23, respectively), indicating that the dye was still present in approximately 25% of the cells and that the negative effect of photoablation was evenly distributed among the blastomeres. It is concluded that zona photoablation may have long-term detrimental effects of a non-topical nature on precompacted mouse embryos in spite of the apparent precision of the laser spot size.

Animals↗