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Biomedical subjects

I Cohen

Publications and source records attributed to I Cohen.

At least 217 records · Page 12Linked to original sources
PubMed1993

Axonal regeneration is associated with glial migration: comparison between the injured optic nerves of fish and rats.

The central nervous systems of mammals and fish differ significantly in their ability to regenerate. Central nervous system axons in the fish readily regenerate after injury, while in mammals they begin to elongate but their growth is aborted at the site of injury, an area previously shown to contain no glial cells. In the present study we compared the ability of glial cells to migrate and thus to repopulate the injured area in fish and rats, and used light and electron microscopy in an attempt to correlate such migration with the ability of axons to traverse this area. One week after the optic nerve was crushed, both axonal and glial responses to injury were similar in fish and rat. In both species glial cells were absent in the injured area (indicated by the disappearance of glial fibrillary acidic protein and vimentin immunoreactive cells from the site of injury in rat and fish, respectively), while at the same time axonal growth, indicated by expression of the growth-associated protein GAP-43, was restricted to the proximal part of the nerve. In fish, 2 weeks after the crush, GAP-43 staining (i.e., growing axons) was seen at the site of injury, in association with migrating vimentin-positive glial cells. One week later the site of injury in the fish optic nerve was repopulated by vimentin-positive glial cells, and GAP-43-positive axons had already traversed the site of injury and reached the distal part of the nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

An integrated software system for quality assurance-related kappa coefficient analysis of intraoperative transesophageal echocardiography interpretive skills.

This report describes the development of a quality assurance-oriented integrated software system designed for an anesthesiology-based intraoperative transesophageal echocardiography service. Entry data include patient and operation demographics, two-dimensional echocardiographic, saline-contrast, and color flow/pulsed Doppler assessments of the heart and great vessels, presented in a defined sequence. A statistical analysis component (kappa coefficient analysis) allows for comparison of intraoperative real-time interpretations with laboratory interpretations made by experienced full-time echocardiographers on a field-by-field basis. This provides a means of quantifying expertise in each individual aspect of the patient examination sequence. We believe that such self-appraisal data are essential for delineating the status and tracking the progress of service being provided.

Echocardiography, Transesophageal↗
PubMed1993

The human decorin gene: intron-exon organization, discovery of two alternatively spliced exons in the 5' untranslated region, and mapping of the gene to chromosome 12q23.

Decorin is a chondroitin/dermatan sulfate proteoglycan expressed by most vascular and avascular connective tissues and, because of its ability to interact with collagen and growth factors, has been implicated in the control of matrix assembly and cellular growth. To understand the molecular mechanisms involved in regulating its tissue expression, we have isolated a number of genomic clones encoding the complete decorin gene. The human decorin gene spans over 38 kb of continuous DNA sequence and contains eight exons and very large introns, two of which are 5.4 and > 13.2 kb. We have discovered two alternatively spliced leader exons, exons Ia and Ib, in the 5' untranslated region. These exons were identified by cloning and sequencing cDNAs obtained by polymerase chain reaction amplification of a fibroblast cDNA library. Using Northern blotting or reverse transcriptase PCR, we detected the two leader exons in a variety of mRNAs isolated from human cell lines and tissues. Interestingly, sequences highly (74-87%) homologous to exons Ia and Ib are found in the 5' untranslated region of avian and bovine decorin, respectively. This high degree of conservation among species suggests regulatory functions for these leader exons. In the 3' untranslated region there are several polyadenylation sites, and at least two of these sites could give rise to the transcripts of approximately 1.6 and approximately 1.9 kb, typically detected in a variety of tissues and cells. Using a genomic clone as the labeled probe and in situ hybridization of human metaphase chromosomes, we have mapped the decorin gene to the discrete region of human chromosome 12q23. This study provides the molecular basis for discerning the transcriptional control of the decorin gene and offers the opportunity to investigate genetic disorders linked to this important human gene.

Alternative Splicing↗
PubMed1993

Molecular cloning of the human proto-oncogene Wnt-5A and mapping of the gene (WNT5A) to chromosome 3p14-p21.

The highly conserved Wnt genes belong to a widely distributed family of presumptive signaling molecules that have been implicated not only in the regulation of normal pattern formation during embryogenesis and differentiation of cell lineages, but also in oncogenic events. All of the known vertebrate Wnt genes encode for 38- to 43-kDa cysteine-rich putative glycoproteins, which have features typical of secreted growth factors: a hydrophobic signal sequence, a conserved asparagine-linked oligosaccharide consensus sequence, and 22 conserved cysteine residues whose relative spacing is maintained. In this study, we report the cloning and sequencing of several overlapping cDNAs encoding approximately 4.1 kb of the human homologue of Wnt-5A. The mature protein contained 343 residues (M(r) approximately 38,000 excluding any post-translational modifications) with a > 93% homology to the reported sequences of other Wnt-5A proteins (> 99% homologous to mouse Wnt-5A). This protein maintained certain features--a hydrophobic signal sequence, the Wnt-1 family "signature sequence" (CKCHGvSGSC), and a number of other conserved amino acid residues: 24 cysteine residues, 4 asparagine-linked oligosaccharide consensus sequences, and a tyrosine sulfation site--that have been found in all other Wnt-5A proteins. Reverse transcriptase PCR analysis of RNA from a variety of human embryonic, neonatal, and adult cells and/or tissues showed that human Wnt-5A expression was detected only in neonatal heart and lung. It may be relevant, however, that the 3'-untranslated region contained numerous AT-rich motifs that could be involved in the rapid degradation of mRNA. Finally, using a combination of Southern blotting, PCR amplification, and in situ hybridization, the human Wnt-5A (WNT5A) gene was mapped to chromosome 3p14-p21.

Amino Acid Sequence↗
PubMed1993

Role of prolonged stimulation of tamoxifen therapy in the etiology of endometrial sarcomas.

We present the first case of heterologous mixed mesodermal tumor that developed 9 years following tamoxifen therapy in a climacteric woman with no previous pelvic irradiation and was initially treated by total abdominal hysterectomy and bilateral salpingo-oophorectomy. She continued tamoxifen therapy for 2 years, following the initial treatment, until the diagnosis of a recurrent tumor by laparotomy. The patient died of the disease 5 months subsequent to the second surgery. The association of prolonged unopposed estrogenic stimulation, with tamoxifen as a possible etiologic factor in the development of endometrial sarcomas, is discussed.

Aged↗
PubMed1993

A clinical computer database entry form for an intraoperative anesthesiology-based transesophageal echocardiography monitoring service.

Transesophageal echocardiography (TEE) has been increasingly applied to supplement and, in instances, to supplant conventional intraoperative cardiac monitoring. Our body of experience (> 1600 intraoperative TEE procedures), combined with insights gleaned from an intramural quality assurance study, and clinical implications of certain recent advances in the field, led us to develop the following TEE computer database entry form. The form, completed intraoperatively, consists of a patient and surgical procedure demographics section, followed by fields based on the TEE examination. The scans encompass transverse plane basal short axis, long axis, and transgastric views of the heart and great vessels. The two-dimensional echocardiographic, saline-contrast, color flow and pulsed Doppler data represent both right and left ventricular performance, valvular function and specific lesions. This database entry form is intended to serve as a guide for performance of a nominally complete intraoperative study and facilitate maintenance of a TEE archive consistent with current advances.

Anesthesia Department, Hospital↗
PubMed1993

Microhysteroscopy and endometrial biopsy results following failed diagnostic dilatation and curettage in women with postmenopausal bleeding.

OBJECTIVE: The aim of this study was twofold: firstly to evaluate and compare the diagnostic precision of the microhysteroscopy (MH) and endometrial biopsy in a group of menopausal women in whom D&C had failed to obtain an adequate endometrial sample, and secondly to quantitate the value of a hysteroscopy in determining endometrial sampling in these patients. METHODS: A Hamou type II CO2 microhysteroscope (MH) was used to evaluate the endocervical canal and the uterine cavity, followed by endometrial sampling. RESULTS: Thirty-nine women were assessed using MH and endometrial biopsy. Histopathology results were available for diagnosis in 29 of them (74.3%). In the remaining ten patients, the MH diagnosis was atrophic endometrium. Biopsy results corroborated with MH in 86.2% (25/29) of the patients with tissue samples. The analysis (r) of this concordance rate was statistically significant (r = 0.96). Sample results for patients with MH determined pathological and normal endometrium corroborated in 83% and 91%, respectively, inclusive of three cases of endometrial adenocarcinoma. The sensitivity, specificity and predictive values for MH alone were 93.7%, 76.9% and 83.3%, respectively. CONCLUSIONS: These significant results are indicative that this simplified endoscopic method surpasses all blind hospital or office endometrial sampling methods. Therefore, we suggest that MH and endometrial sampling should be the initial assessment tool for any type of indication requiring endometrial and uterine cavity assessment.

Aged↗
PubMed1993

cDNA clones from fish optic nerve.

1. The present review describes the results of a cloning that was successfully employed in the study of optic nerve regeneration in fish. 2. Three intermediate filaments (IFs) expressed by the glial fish optic nerve were cloned. 3. By the use of this approach it was possible to resolve the controversial question of whether glial fibrillary acidic protein (GFAP) is expressed in the fish optic nerve. 4. Moreover, as a result of the information that emerged from the cloning, it was possible to raise well-characterized monospecific antibodies and successfully exploit them in order to determine glial cell maturation, lineage and plasticity, monitor the glial cell response to injury of the fish optic nerve, and compare it to that of a non-regenerative system.

Amino Acid Sequence↗
PubMed1993

The inability of preovulatory ovarian scan to predict multifetal pregnancy occurrence in a follow-up of induction of ovulation with menotropins.

OBJECTIVE: To establish the predictive role of preovulatory ovarian ultrasonography in the occurrence of multiple pregnancy after hMG and hCG treatment for anovulatory infertility. DESIGN: Prospective. SETTING: Outpatient Infertility Clinic. PATIENTS: Ninety-five anovulatory women who conceived after gonadotropin therapy. INTERVENTION: Induction of ovulation by hMG and hCG monitored by plasma E2 measurements and ovarian ultrasonography. MAIN OUTCOME MEASURES: All follicles visualized on the day of hCG administration were recorded and divided into the following four groups: group I, 10 to 12 mm; group II, 13 to 15 mm; group III, 16 to 18 mm; and group IV, 19 mm and larger. The sonographic findings were statistically evaluated to 80 singletons and 45 multiple pregnancies. RESULTS: No statistical correlation was found to exist between the number of follicles from the different groups and the number of fetuses. CONCLUSIONS: The number and sizes of follicles visualized on the day of hCG administration have no predictive value regarding the occurrence of a multiple pregnancy.

Adult↗
PubMed1993

Direct in-vivo detection of atypical hormonal expression of a Sertoli-Leydig cell tumour following stimulation with human chorionic gonadotrophin.

A 60-year-old woman presented with progressive hirsutism and elevated serum testosterone levels. Selective bilateral ovarian and adrenal vein catheterization demonstrated mild elevated testosterone and androstenedione levels in the right ovarian vein, which increased considerably 15 minutes following intravenous injection of 5000 IU human chorionic gonadotrophin. Androgen levels decreased remarkably after administration of gonadotrophin hormone releasing hormone-agonist (GnRH-a). On histological examination, diffuse stromal hyperplasia of both ovaries was noted, with a small Sertoli-Leydig cell tumour in the right ovary. This is the first report of preoperative, direct selective diagnosis of a small Sertoli-Leydig cell tumour with such a hormonal expression. Ovarian Sertoli-Leydig cell tumours are rare sex cord stromal tumours that exhibit testicular-like structure and differentiation. These tumours are potentially malignant, can cause progressive virilization (Young & Scully, 1985), and are often clinically manifested as palpable pelvic masses and virilization (Meldrum & Abraham, 1979; Friedman et al., 1985). We describe a patient with postmenopausal virilization due to Sertoli-Leydig cell tumour, in whom a remarkable increase in androgens was detected following intravenous human chorionic gonadotrophin injection, during adrenal and ovarian selective vein blood sampling. A remarkable decrease in the serum androgen level was noticed following an injection of gonadotrophin hormone releasing hormone-agonist (GnRH-a).

Androgens↗
PubMed1993

Endometrial changes in postmenopausal women treated with tamoxifen for breast cancer.

OBJECTIVE: To evaluate whether risk factors, other than tamoxifen, can be identified for the development of endometrial pathologies in postmenopausal breast cancer patients treated with tamoxifen. DESIGN: A cross-sectional study. SETTING: Department of Obstetrics and Gynaecology and Oncology Clinic, Sapir Medical Center, Kfar Saba, Israel. SUBJECTS: 77 asymptomatic postmenopausal women, treated with tamoxifen for breast cancer. Of these, 55 had no endometrial tissue and 22 had endometrial tissue obtained by biopsy. MAIN OUTCOME MEASURES: Demographic characteristics, health habits, risk factors, vaginal ultrasonographic evaluations of endometrial thickness and texture, and histologic evaluations of endometrial biopsies. RESULTS: Overall, there was a high rate (29%) of endometrial pathological change among the 77 asymptomatic postmenopausal women. There were no significant statistical differences in the features tested between the two groups. CONCLUSION: It is impossible to predict which postmenopausal women will develop pathological endometrial changes after treatment with tamoxifen and thus a routine periodic endometrial sampling-follow up is suggested for all postmenopausal women being treated with this agent.

Aged↗
PubMed1993

Ultrasonographic evaluation of the endometrium and correlation with endometrial sampling in postmenopausal patients treated with tamoxifen.

Seventy-two asymptomatic, postmenopausal women treated with tamoxifen for breast cancer were studied prospectively with vaginal ultrasonography, followed by endometrial sampling. Seventy-one patients demonstrated an endometrial echo of more than 5 mm, and one displayed an endometrial echo of less than 5 mm. No patient with an endometrial echo of less than 5 mm displayed any endometrial pathology. Different endometrial pathologic conditions were found when the endometrial echo was over 5 mm. When classifying those patients whose ultrasonic endometrial widths were wider than 5 mm, on the basis of different endometrial histologic findings, no obvious correlation was found between the various pathologic endometrial findings and endometrial thickness. Thus, a "thicker" endometrial sonographic image did not necessarily correlate with pathologic endometrial findings. When ultrasonic endometrial thickness of 5 mm was considered the upper limit of normal, the sensitivity of ultrasonography in correlating to positive histologic findings was 91% and the specificity was 96%. These findings suggest that there is good correlation between endometrial width measured by ultrasonographic assessment and histologic findings.

Adult↗
PubMed1993

Role of actin in platelet function.

Cytochalasin E (CE) was used in this study to evaluate relationships between platelet shape change, pseudopod extension, internal transformation, actin filament assembly, fibrinogen receptor expression, aggregation, clot tension and secretion. Various ratios of G- to F-actin, measured by the DNase inhibition assay, were achieved by using several concentrations of CE in stirred and unstirred thrombin-stimulated platelets. An increased rate of actin polymerization was found in "aggregating" conditions as compared to "activating" conditions, the latter achieved by either absence of stirring or stirring in the presence of the tetrapeptide Arg-Gly-Asp-Ser (RGDS). Larger concentrations of CE were required in aggregated than in activated platelets to obtain G-actin levels analogous to those in resting platelets. Concentrations of polymerizing actin above 20% and 55% for activated and aggregated platelets, respectively, trigger platelet shape change and the extension of pseudopods. Prevention of de novo actin polymerization by CE, added either before or after thrombin stimulation, inhibits fibrinogen binding to platelets. This suggests an involvement of the new actin polymers in fibrinogen receptor exposure. As expected, platelet aggregation and clot tension, which are dependent on fibrinogen receptor exposure, were inhibited by CE. Granular secretion was not dependent on polymerizing actin.

Actins↗
PubMed1993

Spontaneous vaginal deliveries and perineal trauma in Lucea, Jamaica.

In 1991, there were 995 uncomplicated vaginal deliveries at Noel Holmes Hospital (NHH) in Lucea, Jamaica. Seven hundred and forty-two women were discharged with intact perineums. Only 3 episiotomies were performed. These data raise a concern that episiotomy may be overused in the United States.

Delivery, Obstetric↗
PubMed1993

Health care for the homeless: a public concern.

The number of homeless people in the nation and New Orleans continues to increase. It is an important problem for all citizens but is especially so for the social and medical care agencies. As physicians we are morally bound to help the less fortunate of our communities, and we must also protect the community from the illnesses to which the homeless may be more susceptible. However, because very little is accurately and reliably known about the homeless in New Orleans, little can be efficiently done to aid them. We report the results of our brief surveys to stimulate concern and action in the medical community for these unfortunate people.

Adolescent↗
PubMed1993

Anterior vascularized rib strut graft in the treatment of Pott's disease in the young child.

Two young children suffering from acute thoracic kyphosis due to vertebral tuberculosis (Pott's disease) are described. One patient presented with recent onset spastic paraplegia due to cord compression. Anterior decompression and stabilization with a vascularized rib strut graft was performed in both patients. The neurological recovery in the compromised patient was remarkable; spinal stability was achieved in both patients, thus avoiding the necessity for a posterior spinal fusion.

Child, Preschool↗