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Biomedical subjects

M Cohen

Publications and source records attributed to M Cohen.

At least 703 records · Page 39Linked to original sources
PubMed1987

Experimental extra-follicular histogenesis of follicular cysts.

An animal model has been developed in which implantation cysts have been produced very close to developing teeth within the jaws of Vervet monkeys. Various deciduous teeth were extracted from both the maxilla and the mandible of 6 young Vervet monkeys. After 4 weeks, full thickness mucoperiosteal flaps were raised in these areas, up to 6 recipient sites were prepared in each monkey by drilling holes in the alveolar bone and small pieces of autogenous palatal mucosa were placed in these graft recipient sites. One monkey was killed after 5, 8, 22 and 25 weeks respectively and 2 after 52 weeks. Of the 33 implants placed, cyst formation occurred from 11 (33%). The distribution of the cysts was irregular in that 4 cysts were produced in each of 2 animals while no cysts were found in another 2 animals. The cysts produced were filled with keratin and lined partly by a thick keratinising epithelium and partly by a thin non-keratinising epithelium only a few cell layers thick. In one of the animals killed after 52 weeks, the follicle of an erupting premolar tooth had collided with one of the cysts resulting in the cyst lining becoming incorporated into the follicle, partly replacing the follicular reduced enamel epithelium and forming now an integral part of the follicle. This observation supports the hypothesis that the follicular odontogenic keratocyst has an extra-follicular origin arising after the eruption of a tooth into a pre-existing cyst cavity.

Animals↗
PubMed1987

Tissue-specific expression of human provirus ERV3 mRNA in human placenta: two of the three ERV3 mRNAs contain human cellular sequences.

Three polyadenylated RNAs, 9, 7.3, and 3.5 kilobases long, of a human endogenous retrovirus, ERV3, are abundant in human placental chorion, representing about 0.03 to 0.05% of the total mRNA. We characterized the structure of these mRNAs by Northern blot and S1 nuclease mapping analyses. We found that all three RNAs were spliced mRNAs that lacked 5.9 kilobases of proviral sequence, including the gag gene and most of the pol gene. In contrast to the transcription pattern usual for other retroviruses, the transcription pattern of the ERV3 provirus did not include a genome-length mRNA. All three of the ERV3 mRNAs initiated transcription at the same point in the 5' long terminal repeat (LTR) and contained identical splice junctions in the provirus. The 3.5-kilobase RNA was a typical subgenomic proviral mRNA, with its polyadenylation site in the 3' LTR. The two larger ERV3 mRNAs, however, extended through the polyadenylation site in the 3' LTR and were spliced at a second position approximately 370 nucleotides downstream from the 3' LTR. This finding suggests that when the ERV3 retrovirus integrated at this genomic locus in an ancestor of humans, it integrated within or adjacent to a cellular gene.

Base Sequence↗
PubMed1987

T84 cell receptor binding and guanyl cyclase activation by Escherichia coli heat-stable toxin.

Escherichia coli heat-stable enterotoxin (STa) induces intestinal secretion by binding to enterocyte receptors and activating the guanylate cyclase-guanosine 3',5'-cyclic monophosphate (cGMP) system. The intermediate steps between binding of STa and secretion are poorly understood, due in part to the lack of a convenient system to study the effects of STa at the cellular level. To establish such a model, we investigated the binding of 125I-STa, STa activation of guanylate cyclase, and STa-induced increase in cGMP production in a well-characterized human colonic cell line, T84. Binding was specific, linear with cell number, and time, temperature and pH dependent, and reversible. ST may also be internalized by these cells. Addition of unlabeled STa competitively inhibited binding of 125I-STa. These parameters closely resemble those described in intact rat enterocytes and cell-free membrane preparations. STa stimulated guanylate cyclase and cGMP production in a dose-related manner. The similar dose-response relationships for binding, guanylate cyclase stimulation by STa, and cGMP production suggest that the guanylate cyclase-cGMP system is coupled to ST occupancy of specific receptors. These data, together with the fact that STa induces chloride secretion from T84 cells suggest that T84 cells are a suitable and convenient system to study the cellular mechanism of action of STa.

Bacterial Toxins↗
PubMed1987

Isolated atrial septal defect with pulmonary vascular obstructive disease--long-term follow-up and prediction of outcome after surgical correction.

UNLABELLED: We examined the cases of 702 patients found to have isolated atrial septal defect of the secundum or sinus venosus type at catheterization from 1953 to 1978. Forty patients (6%), 34 women and six men, had pulmonary vascular obstructive disease, with a total pulmonary resistance greater than 7 U/m2; of these patients 26 (mean age 47 years) underwent surgical closure and 14 (mean age 44 years) received medical treatment. All patients were followed for at least 4 years, with a median follow-up of 12 years. At the most recent follow-up, 17 of the 40 patients were dead. Of the 22 surgically treated patients with total pulmonary resistance less than 15 U/m2, 19 were alive with significant regression of symptoms. All four surgically treated patients with total pulmonary resistance greater than or equal to 15 U/m2 were dead. Of the five medically treated patients with total pulmonary resistance less than 15 U/m2, four had died, and one was alive with significant progression of symptoms. Of the nine medically treated patients with total pulmonary resistance greater than or equal to 15 U/m2, six had died and the three survivors had progression of symptoms. In the surgically treated group, the following variables correlated with survival: total pulmonary resistance (p less than .00001), pulmonary arteriolar resistance (p less than .00001), pulmonary-to-systemic resistance ratio (p = .004), systemic arterial oxygen saturation (p = .005), and pulmonary arterial oxygen saturation (p = .007). IN CONCLUSION: (1) Atrial septal defect with high total pulmonary resistance is uncommon and predominates in adult female patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Dermatophytosis of the diaper area.

Six cases of dermatophytosis of the diaper area due to either Epidermophyton floccosum or Trichophyton rubrum are described herein. The clinical and laboratory features of these patients and those reported in the literature are highlighted. Dermatophytosis should be considered in the differential diagnosis of rashes in the diaper area. Most standard remedies for diaper rash will not be effective or may exacerbate diaper dermatophytosis. Recognition of this condition by the clinician will lead to earlier rational treatment and may avoid the delay caused by therapy.

Clotrimazole↗
PubMed1987

Multi-centre open study of a triphasic levonorgestrel-ethinyloestradiol combined oral contraceptive ('Trinordiol').

A long-term, multi-centre open study was carried out to evaluate the efficacy, cycle control and side-effects with a triphasic, combined oral contraceptive containing levonorgestrel and ethinyloestradiol ('Trinordiol'). A total of 2517 women completing at least 1 cycle of treatment was followed up at 2 to 3-monthly intervals; the overall number of cycles on treatment was 37,090. During treatment, only 2 pregnancies occurred which were attributable to pill failure. Cycle control was good: cycle irregularities were 9.6% overall, but were most common (19.6%) during the first 3 cycles. Only 3.8% of patients withdrew from the study for this reason. Side-effects were those commonly seen with oral contraceptives, and they produced a drop-out rate of only 13.9%. There were no clinically significant effects on blood pressure or body weight. The results also suggested that 'Trinordiol' has a beneficial effect on pre-existing acne.

Acne Vulgaris↗
PubMed1987

The use of neuropsychological evaluation in the medical management of subdural empyema.

Subdural empyema is in itself an uncommon complication of infection in childhood and localization of the infection to the parafalcine area is rare. This paper presents a case study of a teenager with subdural empyema resulting from paranasal sinusitis, who presented as a parafalcine syndrome and was treated successfully without neurosurgical intervention. Results of repeat neuropsychological evaluation (premorbid, 17 days into treatment, and after six months), correlated with changes seen on serial CT scanning during treatment and follow up. More importantly, the neuropsychological evaluation was clinically more sensitive than the traditional neurological examination in assessing changes in cortical integrity during the course of recovery. Thus, neuropsychological evaluation proved to be a valuable supplement to the neurological examination in exploring morbidity and assisting in treatment decision making in the management of subdural empyema.

Journal Article↗
PubMed1987

The neuropsychological approach to the remediation of dyslexia.

The neuropsychological approach to remediation emphasizes the use of intact areas of higher cortical functioning in the development of remedial strategies while minimizing the emphasis placed upon dysfunctional cortical areas. This investigation was directed towards evaluating the effectiveness of the neuropsychological approach to the remediation of developmental dyslexia in school age children previously placed in self-contained classrooms for the learning disabled due to reading failure. A significant improvement in word recognition skills was demonstrated with a similar, but nonsignificant, trend noted in reading comprehension.

Journal Article↗
PubMed1987

Skin tags: a cutaneous marker for diabetes mellitus.

Two hundred and sixteen non hospitalized patients with skin tags (ST) were studied for the presence of diabetes mellitus (DM) and obesity. Overt DM was found in 57 (26.3%) patients and impaired glucose tolerance test was found in 17 (7.9%) patients. Sixteen new cases of DM were found among this group. All the diabetic patients in the study population had non-insulin dependent DM. Sixty-two (28.7%) of the patients were obese. No correlation was found between the localization, size, colour and number of the ST and the presence of DM. Our study indicates that ST are not associated with increased incidence of obesity compared to the general population. On the other hand, ST are associated with impaired carbohydrate metabolism, and may serve as means for identifying patients at increasing risk of having DM.

Carbohydrate Metabolism↗
PubMed1987

Avascular necrosis of the femoral head secondary to corticosteroid therapy for graft-versus-host disease after marrow transplantation: effective therapy with hip arthroplasty.

Of 50 patients surviving 2 years or longer after HLA-identical sibling bone marrow transplantation for haematological malignancy or severe aplastic anaemia, five developed avascular necrosis of the femoral head. All had previously received corticosteroid therapy post-transplant for graft-versus-host disease. Median day of onset of symptoms was 545 days post-transplant (range 249-731). Clinical, radiological and radionuclide findings were typical of osteonecrosis. One patient has had bilateral hemiarthroplasties and one total hip replacements performed, both with excellent results. Bilateral arthroplasties are planned for a third patient but, interestingly, the disease process in the other two patients has been relatively mild with no progression over a period of greater than 256 and greater than 825 days, respectively. Since one patient had as little as 14 days treatment with prednisone, this complication should be borne in mind when designing prophylactic regimens for minimisation of GVHD that include corticosteroids.

Adrenal Cortex Hormones↗
PubMed1987

A low-dose triphasic oral contraceptive.

Controlled clinical investigations of a three-phase, low-dose oral contraceptive combination of levonorgestrel and ethinyl estradiol were conducted at 17 sites in the United States and 60 sites in the United Kingdom. A day 1 start in cycle one with no backup contraception was used. A total of 3546 female volunteers participated in 35,036 cycles. Medication was missed in 2688 (7.7%) cycles. Nine pregnancies were reported for an uncorrected use-effectiveness rate of 0.33 per 100 woman-years. Cycle control was excellent, bleeding irregularities were minimal, and the incidence of side effects was very low. No clinically significant variations in blood pressure means or weight means were observed. Carbohydrate and lipid metabolism studies were limited to 6 months and showed minimal alterations. Subject compliance with the preparation was excellent. It is concluded that this triphasic oral contraceptive with its varying ratios of levonorgestrel and ethinyl estradiol is an effective, predictable, and well-tolerated combination oral contraceptive.

Adolescent↗
PubMed1987

Medical care and demographic characteristics of 'difficult' patients.

This pilot study describes the medical care and demographic characteristics of "difficult" patients as compared with randomly selected patients of a community-based family practice center. Ninety-two difficult patients were identified by asking physicians to indicate those patients whose care they considered difficult. Charts of 166 randomly selected patients were then compared with those of the difficult patients. The difficult patient group was older, more often divorced or widowed, and had a higher percentage of women than the random patient group. The difficult patient group also had more acute problems, chronic problems, medications, x-ray examinations, blood tests, physician referrals, and visits to the family practice center. After covariance analysis adjusting for age and sex, significant differences remained between the two groups for chronic problems, blood tests, medications, and visits to the family practice center. The two patient groups did not differ significantly in household composition, payment status, or provider continuity. The data suggest that, although there are different types of difficult patients, there may be certain medical and demographic features that are common to many of them. Many physicians suspect that difficult patients suffer from a "thick-chart syndrome," a syndrome confirmed to exist by this study.

Adult↗