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Biomedical subjects

L Cohen

Publications and source records attributed to L Cohen.

At least 307 records · Page 17Linked to original sources
PubMed1990

[Chemotherapy in cancer of the prostate].

The most classical treatment of metastatic prostatic adenocarcinoma is hormone therapy. Most often, chemotherapy is proposed only when the tumor becomes hormonally unresponsive. But evaluation of its efficacy is impaired by the diversity of inclusion criteria used and by the different criteria of response assessment. Results of randomized, comparative studies show that all cytotoxic agents currently available have a similar response rate (about 30 to 40%). Use of combined chemotherapy does not seem to significantly improve these results. Several others ways have been proposed which attempt to improve the efficacy of chemotherapy (androgen stimulation, priming chemotherapy, adjuvant or neo-adjuvant chemotherapy...) but, most probably, progress will come from the discovery of more effective and selective cytotoxic agents, and not from the increase of clinical trials with the same agents.

Antineoplastic Agents↗
PubMed1990

[Treatment of hemorrhagic cystitis caused by cyclophosphamide using intravesical instillation of potassium alum. Apropos of 5 cases].

Five patients with malignant hemopathies, including four treated by bone marrow transplantation, developed cyclophosphamide-induced hemorrhagic cystitis that failed to respond to the usual treatments. Each was treated by continuous irrigation of the bladder with potassium alum. Hematuria ceased in three patients followed up for 5 to 10 months. A review of the literature confirmed the 75% success rate of this treatment. No local side effects were recorded, but one patient had a single seizure.

Administration, Intravesical↗
PubMed1990

[Hautmann enterocystoplasty. Clinical and urodynamic study in 24 patients].

Twenty-four patients with invasive bladder cancer underwent Hautmann enterocystoplasty. A study of the urinary continence revealed 100 per cent of good results during the day and 87.5 per cent of good results at night. Urodynamic investigation after 3 months revealed that only one patient presented with peristaltic waves and that the postmicturating residual urine volume was always less than 100 cc. There was no mortality in this series. The only uncertainty concerns the long-term outcome of these patients because of the risk of incomplete emptying and distension of the neobladder.

Aged↗
PubMed1990

[Treatment of urethral stenosis using a pedicled flap of the scrotal skin. Long-term results in 16 patients].

The scrotal skin is vascularized in part by means of the superficial perineal branch of the internal pudendal artery. This nutrient pedicle, together with the scrotal skin dependent on it, can be isolated. The urethra is approached via the perineum. The stricture is incised longitudinally right down to the healthy area. The scrotal flap and pedicle are mobilized, and then anastomosed along the edges of the urethra. From March 1983 through April 1987, sixteen patients have been operated. Postoperative results: the mean follow-up for the 16 patients is 60 months with extremes of 24 and 66 months. 13/16 patients show good results (81%). 3/16 patients show poor results with recurrence of the stricture localized at the junction of the flap and healthy urethra. Such recurrences have yielded to treatment, in two cases, by optical urethrotomy and, in the other case, by means of a new scrotal flap.

Follow-Up Studies↗
PubMed1990

[Low-pressure enterocystoplasty after prostato-cystectomy for cancer. Apropos of 13 cases].

Thirteen patients were operated for bladder carcinoma, from November 1987 to September 1988, using a Camey type II low pressure ileal bladder replacement. Clinical, radiological and urodynamic findings were studied. Diurnal continence was always acquired at three months. In terms of nocturnal continence, only 75 percent of the patients are comfortable, while two patients require oxybutinin to remain continent. Urodynamic exploration showed a low pressure in 8 patients, but a high pressure peak in 4 patients. Radiological study showed integrity of the urinary tract. This work confirmed the improvement obtained with the Camey II procedure. Nevertheless, it also shows the failure of the method with occasional high pressure peaks. We think that a more anatomical bladder reconstruction, such as Hautmann Pouch, may improve the results for nocturnal continence. This needs to be confirmed by a comparative study.

Aged↗
PubMed1990

Influence of dental school experience on sealant use by British dentists.

Dental schools can play an important role in promoting the appropriate use of sealants. The purpose of this study was to examine the dental school experience with sealants of British dentists and its effect on the use of sealants in practice. A postal survey of a representative sample of British dentists (n = 1000) was conducted. The response rate was 73.7 per cent. Approximately 39 per cent of the respondents reported that they had received sealant training in dental school. Both classroom and clinical sealant training received favourable adequacy ratings. Adequacy ratings were found to increase with graduation year group. In general, the dentists' perceptions of the value of sealants in the eyes of former classmates and faculty were positive. Although not statistically significant, there was a trend toward greater sealant use among those respondents who had received sealant training in dental school.

Attitude of Health Personnel↗
PubMed1989

[Accidental discovery of renal cancer by ultrasonography].

A retrospective study of 152 consecutive patients admitted for renal carcinoma between January, 1969 and August, 1987 showed that these patients could be divided into two groups, the dividing line being 1980, date of the advent of ultrasonography. Compared with the 68 patients treated between 1969 and 1980, the 84 patients treated between 1981 and 1987 had a significantly greater number of asymptomatic renal carcinomas. The asymptomatic tumours discovered incidentally by ultrasounds were less advanced than the symptomatic tumours, the difference between the 2 groups being highly significant. The diagnosis of asymptomatic renal carcinoma at an early stage suggests that these tumours might have a better prognosis. These data underline the usefulness of a systematic study of the kidney during all abdominal or vesicoprostatic ultrasonographic explorations.

Female↗
PubMed1989

Extinction of expression of the translocated myc gene in somatic cell hybrids between mouse myeloma and L-cells.

Most murine plasma-cell tumors show a t(12;15) reciprocal chromosomal translocation which truncates the first exon of one of the myc gene alleles and fuses it to one of the switch regions of the immunoglobulin (Ig) heavy-chain locus. This results in constitutive activation of the translocated myc gene and the production of smaller-sized mRNA molecules, which are initiated at new sites in the first myc intron. The normal myc allele is not expressed in these myeloma cells. We have studied the expression of the translocated myc gene in somatic cell hybrids between mouse myeloma and L-cells. Our previous findings show that Ig gene expression is extinguished in such hybrids. In the present work we found that the hybrids contain the normal and translocated myc genes. In contrast to the myeloma parental cells which express the translocated myc gene, the hybrids are similar to the L-cells in expressing only the normal myc allele. Our results suggest that the L-cell, fibroblast-like phenotype, is dominant in these hybrids, and show that the translocated myc gene is expressed in a tissue-specific manner in the context of the myeloma cell, and is not expressed when subjected to a fibroblast-like cellular environment.

Alleles↗
PubMed1989

Multiple protein-DNA interactions within the human interferon-beta regulatory element.

High efficiency nuclear protein extracts were prepared from uninduced and recombinant interferon (IFN-alpha 2-primed Sendai virus-induced HeLa S3 cells and analyzed for DNA binding proteins specific for the human interferon-beta regulatory element (IRE). Analysis of protein-DNA interactions by a gel electrophoresis DNA binding assay resolved three complexes (designated A, B, and C) specific for the IRE probe (-79 to -36) in uninduced and induced cells. Competition studies using greater than a 100-fold molar excess of unlabeled DNA fragments representing different IFN-beta promoter sequences localized the DNA binding domain to the region -79 to -64 (P1 probe), a region previously shown to be essential for virus-inducible gene expression. Other adjacent IFN-beta segments including the negative regulatory element (-65 to -30) as well as the SV40 enhancer, c-fos serum-responsive element, and IFN-alpha 1 promoter fragment (-131 to -71) were unable to compete for the IRE binding protein. The 16-base pair enhancer core (P1 probe) specifically bound similar amounts of protein from uninduced and induced extracts; a synthetic tetrahexamer, AAGTGA, competed efficiently for the binding to the P1 region. Competition studies indicated that adjacent upstream IFN-beta DNA sequences -94 to -78 (P5) also contained a sequence motif capable of binding the P1 protein. In vitro transcription of the IFN-beta template in the HeLa nuclear extracts was partially inhibited when increasing amounts of competitor IRE fragment were added to the reaction. These results demonstrate that multiple DNA sequence motifs within the IFN-beta regulatory element interact to bind transcription regulatory proteins which are present in normal and virus-infected HeLa cells.

Base Sequence↗
PubMed1989

Neutron therapy for nonresectable radioresistant tumors.

Locally advanced, nonresectable, radioresistant tumors can often be ablated by external irradiation using high-energy fast neutron beams. Long-term local control has been achieved in a wide range of malignant tumors, notably sarcomas of bone and soft tissue and adenocarcinomas in various sites. Complete response and long-term remission, with local control rates between 50% and 70%, have been reported in a number of very large osteogenic sarcomas, soft-tissue sarcomas (particularly neurogenic tumors), melanomas, and adenocarcinomas of the alimentary tract. Malignant salivary gland tumors and carcinoma of the prostate appear to be the most responsive to neutrons, with a high frequency (70% to 90%) of successful remission and significantly improved survival even in advanced stages of disease. The biological mechanisms underlying radioresistance of tumor cells and the rationale for using heavily ionizing particles are described. Neutrons are shown to be a valuable adjunct in managing nonresectable malignant tumors that resist conventional therapy.

Fast Neutrons↗
PubMed1989

Effects of the pure antiandrogen RU 23.903 (anandron) on sexuality, aggression, and mood in male-to-female transsexuals.

Sexuality, aggression, and mood were investigated in 14 presurgical male-to-female transsexuals, undergoing antiandrogenic treatment with anandron, a pure antiandrogen. Subjects were given a test battery the morning prior to treatment onset and after 8 weeks of treatment. In addition they were requested to complete daily forms concerned with sexual behavior and mood. Morning erections and the frequency of thoughts and fantasies about sex decreased after anandron intake. Aggressive feelings were uncorrelated with testosterone level. Moods such as level of energy, feelings of relaxation, fatigue, and feelings of tension and anxiety appeared to fluctuate more as a consequence of anandron intake than did moods such as cheerful, sociable and friendly, gloomy and unhappy, irritated and changeable. The latter remained at a constant level.

Adult↗
PubMed1989

Outlook of British dentists towards their profession.

Dental practice in Britain has undergone significant changes in recent years. These changes have undoubtedly affected the outlook of dentists towards dentistry. This study was undertaken to examine the current outlook of general dental practitioners working in the General Dental Service. A representative sample of 1000 dentists was surveyed by mail. The response rate was 73.7 per cent. Most characteristic of the respondents' outlook on various aspects of their profession is the wide diversity of opinion. Neither respondent gender or practice location were associated with outlook. More preventively oriented dentists and those whose practices were most busy, however, were found to have a more positive outlook.

Attitude of Health Personnel↗
PubMed1989

Normal tissue reactions and complications following high-energy neutron beam therapy: I. Crude response rates.

The incidence of significant complications (fibrosis, ulceration, necrosis of bone or soft tissue or serious functional impairment) was determined in relation to neutron dosage and follow-up time for 5 anatomical sites totalling 617 patients who had survived 2 or more years following treatment. The regions studied were head and neck (268 patients), thorax (lung and esophagus, 76 patients), upper abdomen (132 patients), pelvis (prostate and bladder, 114 patients) and extremities (27 patients). Neutron doses ranged from 16 to 28 Gy. All patients were followed until death or up to 10 years after treatment. A total of 109 complications were observed yielding a crude complication rate of 18% for the whole series. Observed complication rates were 7% in the 16-20 Gy dose range, 19% between 20 and 24 Gy, and 33% in patients receiving more than 24 Gy. Probit analysis of the data indicated a median effective dose (50% complications) of 29 (+/- 0.5) Gy with an estimated standard deviation of 8 Gy. A reasonable estimate of "tolerance" may then be taken as 29 - 8 = 21 Gy. Comparing the 5 anatomical sites revealed no significant differences in estimated tolerance doses. With the available data, no effect of field-size or target volume could be demonstrated. The incidence of complications apparently increases with time in long-term survivors. Although the overall incidence is only 18%, actuarial analysis of the data suggests that the complication rate might have exceeded 50% if all treated patients had survived 10 years. It is concluded that, with the exception of the nervous system and possibly other viscera, a neutron dose of 20 Gy (in 12 fractions over 4 weeks) represents a practical tolerance limit for all sites.

Abdomen↗
PubMed1989

Failure of accelerated neutron therapy to control high grade astrocytomas.

Sixty-two patients with high grade malignant astrocytoma were treated with fast neutrons using three different treatment schemes to evaluate the effect of shortening the overall time. Dose and fraction number were kept constant. The total dose was 16-18 neutron Gy delivered in six fractions, weekly for 6 weeks, twice a week over 3-4 weeks, or three times a week over 2 weeks. There were no obvious differences in survival times among the three groups. We conclude that accelerated neutron therapy does not improve survival of patients with grade 3 and 4 astrocytoma.

Adult↗
PubMed1989

Induction of human interferon gene expression is associated with a nuclear factor that interacts with the NF-kappa B site of the human immunodeficiency virus enhancer.

The relationship between transcription of alpha and beta interferon (IFN-alpha and IFN-beta) genes and the interaction of IFN promoter-binding transcription factors has been examined in monoblastoid U937 cells following priming with recombinant IFN-alpha 2 (rIFN-alpha 2) and Sendai virus induction. Pretreatment of U937 cells with rIFN-alpha 2 prior to Sendai virus infection increased the mRNA levels of IFN-alpha 1, IFN-alpha 2, and IFN-beta as well as the final yield of biologically active IFN. Analysis of nuclear protein-IFN promoter DNA interactions by electrophoretic mobility-shift assays demonstrated increased factor binding to IFN-alpha 1 and IFN-beta regulatory domains, although no new induction-specific complexes were identified. On the basis of competition electrophoretic mobility-shift assay results, factors interacting with the IFN-alpha 1 and IFN-beta promoters appear to be distinct DNA-binding proteins. U937 factor binding was localized to the P2 domain (-64 to -55) of the IFN-beta regulatory element, a sequence motif with 80% homology to the recognition site of transcription factor NF-kappa B. Protein-DNA interactions within the IFN-beta P2 domain were, in fact, specifically competed by either excess homologous P2 fragment or the human immunodeficiency virus enhancer element which contains two duplicated NF-kappa B recognition sites. Hybrid promoter-chloramphenicol acetyltransferase fusion plasmids, containing either the IFN-beta regulatory element or the human immunodeficiency virus enhancer element linked to the simian virus 40 promoter, were analyzed for virus and phorbol ester inducibility in epithelial and lymphoid cells, respectively. In the 293 cell line, both plasmids were constitutively expressed but not virus inducible, while in Jurkat cells, chloramphenicol acetyltransferase activity from these plasmids was induced by tumor-promoting agent treatment. These experiments suggest that induction of IFN gene expression may be controlled in part by transcription regulatory proteins binding to an NF-kappa B-like site within the IFN-beta promoter.

Base Sequence↗