Search PubMed⌕ Search

Biomedical subjects

D Cohen

Publications and source records attributed to D Cohen.

At least 163 records · Page 9Linked to original sources
PubMed1999

Eustachian tube teratoma and its terminological correctness.

Teratomas are germ cell tumours usually found in the young and are characteristically composed of tissue foreign to the place where they arise. Two teratomas of the middle ear were first described in 1866 and since then, and to the best of our knowledge, 19 additional cases have been reported in the literature under different terms such as hairy congenital polyps, epidermoid cysts, dermoid cysts, hamartoma, cutaneous teratoma and teratomas. The difficulty in classifying germ cell tumours may explain the different terminologies encountered in the literature. The authors describe a case of teratoma of the eustachian tube presenting as a mass in the middle and external ear of a 10-week-old girl. Using this case, a review of the literature is performed in light of the new classification of germ cell tumours proposed by the World Health Organization (WHO). It is of note that most of the teratomas that present in the middle ear arise from, or involve, the eustachian tube.

Ear Neoplasms↗
PubMed1999

Characterization of the Absolute Crystal Polarity across Twin Boundaries in Gallium Phosphide Using Convergent-Beam Electron Diffraction.

: The measurement of absolute crystal polarity is crucial to understanding the structural properties of many planar defects in compound semiconductors. Grain boundaries, including twin boundaries, in the sphalerite lattice are uniquely characterized by the crystallographic misorientation of individual grains and the direction of the crystal polarity in domains adjoining the grain boundary. To evaluate crystal polarity in gallium phosphide (GaP), asymmetrical interference contrast in convergent-beam electron-diffraction (CBED) patterns was used to ascertain the nature and direction of polar bonds. The direction of the asymmetry in the electron diffraction reflections was correlated with the crystal polarity of a sample with known polarity. The CBED technique was applied to determine the polar orientation of grains adjoining Sigma = 3 coherent and lateral twin boundaries in polycrystalline GaP.

Journal Article↗
PubMed1999

A systemic and value-based approach to strategic reform of the mental health system.

Most writers now recognize that mental health policy and the mental health system are extremely resistant to real changes that reflect genuine biopsychosocial paradigms of mental disorder. Writers bemoaning the intransigence of the mental health system tend to focus on a small analytical level, only to find themselves mired in the rationalities of the existing system. Problems are acknowledged to be system-wide, yet few writers have used a method of analysis appropriate for systemic problems. Drawing upon the General System Theory (GST) analytical perspective, this article advances a systematic approach to understand the mental health system and to facilitate the development of reform strategies that recognize the system's complexity and changing nature. The article first discusses the failure of major reform efforts in the mental health system and the limitations of mainstream analysis of mental health politics and policies with respect to the objectives of analysis and reform. This article describes how systems thinking has thus far influenced the study of the mental health policy and politics system, and argues that a systemic perspective is profitable for reconceiving the mental health system, enabling a fresh basis for the development of reform strategies. The mental health system should be seen as a social system influenced by larger political and economic dimensions, not just as a 'delivery system' scientifically constructed by neutral experts. Furthermore, the policy planning process should be viewed as part and parcel of a mental health system modeled as complex and dynamic. The systemic perspective outlined here should help both to clarify the value-based objectives that we hold for the system and, consequently, to plan for the strategic reforms that have so far eluded us.

Canada↗
PubMed1999

Sphincter pharyngoplasty for the surgical management of speech dysfunction associated with velocardiofacial syndrome.

There are no reports in the literature that document the effectiveness of sphincter pharyngoplasty as a surgical alternative to pharyngeal flap for management of velopharyngeal dysfunction in patients with velocardiofacial syndrome. A retrospective review of patients with velocardiofacial syndrome was undertaken at our tertiary cleft care centre. All patients were managed between 1984 and 1996 at the Cleft Palate and Craniofacial Deformities Institute, St Louis Children's Hospital. Subjects (n = 19) underwent velopharyngeal surgical management on the basis of perceptual speech evaluations and instrumental assessments of inadequate velopharyngeal closure. All patients had a molecular diagnosis of velocardiofacial syndrome based on fluorescent in situ hybridisation analysis of peripheral blood lymphocytes and independent evaluation by a medical geneticist. Surgical outcome was classified as successful if perceptual speech assessment indicated elimination of hypernasality, nasal emission and turbulence, and instrumental assessment indicated 100% velopharyngeal closure. Results showed that 18 of 19 patients were managed successfully with sphincter pharyngoplasty. Our data corroborate that sphincter pharyngoplasty is a reasonable alternative to pharyngeal flap in patients with velopharyngeal dysfunction secondary to velocardiofacial syndrome.

Adolescent↗
PubMed1999

A night with Venus: partner assessments and high-risk sexual encounters.

This study examined partner assessments and high-risk sexual encounters among STD clinic patients. Participants were 42 English-speaking attendees of a public STD clinic in Southern California with ages ranging between 18 and 60. Twelve focus groups were conducted. Qualitative data from the focus groups were analyzed using grounded theory. The analysis resulted in delineating five temporally-ordered stages of causal sexual encounters. Participants reported that they did not use condoms when they perceived new sexual partners as being safe. Instead of directly addressing their partner's sexual history, they relied heavily on both visual and verbal cues to judge if their partner was clean, or disease-free. This assessment process reflects an error in judgement, particularly because most of the participants had already contracted a STD. Suggestions are provided for incorporating the information about the partner assessment process into AIDS educational programmes.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Case series: catatonic syndrome in young people.

This article reviews all recent (1977-1997) reports on catatonic adolescents and summarizes the 9 consecutive cases seen at the authors' institution during the past 6 years. Catatonia occurs infrequently in adolescents (0.6% of the inpatient population), but it appears to be a severe syndrome in adolescents of both sexes. Diagnoses associated with catatonia are diverse, including in this series: schizophrenia (n = 6), psychotic depression (n = 1), mania (n = 1), and schizophreniform disorder (n = 1). Two patients had a previous history of pervasive developmental disorder. In the literature, catatonia was also reported in children with organic condition (e.g., epilepsy, encephalitis). Therapeutic management depends on the specific causes, but several points need to be stressed: (1) the frequency of neuroleptic-induced adverse effects; (2) the potential efficacy of sedative drugs on motor signs; (3) the possible use of electroconvulsive therapy; and (4) the necessity to manage family reactions and fears, which are frequent causes of noncooperation. It is concluded that catatonia is an infrequent but severe condition in young people. While symptomatology, etiologies, complications, and treatment are similar to those reported in the adult literature, findings differ with regard to the female-male ratio and the relative frequencies of associated mental disorders.

Adolescent↗
PubMed1999

Vaccination against shigellosis with attenuated Shigella flexneri 2a strain SC602.

The Shigella flexneri 2a SC602 vaccine candidate carries deletions of the plasmid-borne virulence gene icsA (mediating intra- and intercellular spread) and the chromosomal locus iuc (encoding aerobactin) (S. Barzu, A. Fontaine, P. J. Sansonetti, and A. Phalipon, Infect. Immun. 64:1190-1196, 1996). Dose selection studies showed that SC602 causes shigellosis in a majority of volunteers when 3 x 10(8) or 2 x 10(6) CFU are ingested. In contrast, a dose of 10(4) CFU was associated with transient fever or mild diarrhea in 2 of 15 volunteers. All volunteers receiving single doses of >/=10(4) CFU excreted S. flexneri 2a, and this colonization induced significant antibody-secreting cell and enzyme-linked immunosorbent assay responses against S. flexneri 2a lipopolysaccharide in two-thirds of the vaccinees. Seven volunteers who had been vaccinated 8 weeks earlier with a single dose of 10(4) CFU and 7 control subjects were challenged with 2 x 10(3) CFU of virulent S. flexneri 2a organisms. Six of the control volunteers developed shigellosis with fever and severe diarrhea or dysentery, while none of the vaccinees had fever, dysentery, or severe symptoms (P = 0. 005). Three vaccinees experienced mild diarrhea, and these subjects had lower antibody titers than did the fully protected volunteers. Although the apparent window of safety is narrow, SC602 is the first example of an attenuated S. flexneri 2a candidate vaccine that provides protection against shigellosis in a stringent, human challenge model.

Bacterial Proteins↗
PubMed1999

Domiciliary midwifery support in high-risk pregnancy incorporating telephonic fetal heart rate monitoring: a health technology randomized assessment.

We conducted a health technology assessment of the care of women with high-risk pregnancies in the South Wales valleys. Women in the control arm were intended to receive conventional care with standard midwifery visits. Women in the intervention arm received additional or longer visits and domiciliary fetal heart rate telemonitoring. Eighty-one mothers were randomized. There were significant differences in midwifery intervention resources between domiciliary and control groups, with the former receiving a mean of 3.7 visits lasting 33.5 min, compared with 1.4 visits lasting 12.8 min for the latter. There were slightly more spontaneous labours and fewer Caesarean sections in the domiciliary group. Maternal satisfaction and anxiety were high in both groups. Domiciliary care increased the service costs by 21.02 Pounds per woman in terms of extra midwife travel and visiting time, and by a further 18.38 Pounds per woman in home monitoring equipment costs. This, however, was more than offset by health service savings from fewer clinic visits (35.60 Pounds) and fewer clinic ultrasound scans (9.01 Pounds). Adding the reductions in lost productivity to women and their partners (34.51 Pounds) suggests that domiciliary care was cheaper than conventional care, even if it did not greatly reduce inpatient days (a reduction nonetheless saving 184.24 Pounds). While clinical processes were similar in both groups, there were useful practical advantages and savings for patients and the health service from the domiciliary intervention.

Anxiety↗
PubMed1999

Alcohol availability and homicide in New Orleans: conceptual considerations for small area analysis of the effect of alcohol outlet density.

OBJECTIVE: To determine the geographic relation between homicide rate and two competing measures of exposure to alcohol outlets, alcohol outlets per square mile and alcohol outlets per person. METHOD: Homicides occurring in 1994 and 1995 and on-sale and off-sale alcohol outlets with active 1995 licenses were geocoded by address for aggregation at the census tract level. Ecologic analysis of the 155 urban residential census tracts in New Orleans was conducted with controls for potential sociodemographic confounders (% black, % adults unemployed, % unmarried households, and ratio males 15-24/males 35-44). RESULTS: After logarithmic transformation of all study variables, sociodemographic confounders alone accounted for 58% (R2 = .58) of the variance of homicide rates. Adding off-sale alcohol outlet density to the models, measured (beta +/- SE) either as outlets per square mile (beta = .211 +/- .062) or outlets per person (beta = .244 +/- .063), yielded strong geographic relations with homicide and increased the amount of variance explained (R2 = .62). A 10% higher off-sale outlet density accounted for a 2.4% higher homicide rate. CONCLUSIONS: Both off-sale alcohol outlets per square mile and off-sale outlets per person demonstrate strong geographic associations with homicide rates among urban residential census tracts in New Orleans. These findings suggest that communities faced with high rates of assaultive violence might consider policy interventions that address alcohol outlet related factors.

Adolescent↗
PubMed1999

Cost as a barrier to condom use: the evidence for condom subsidies in the United States.

OBJECTIVES: This study sought to determine the impact of price on condom use. METHODS: A program based on distribution of condoms at no charge was replaced with one providing low-cost condoms (25 cents). Pretest and posttest surveys asked about condom use among persons reporting 2 or more sex partners. RESULTS: At pretest, 57% of respondents had obtained free condoms, and 77% had used a condom during their most recent sexual encounter. When the price was raised to 25 cents, the respective percentages decreased to 30% and 64%. CONCLUSIONS: Cost is a barrier to condom use. Free condoms should be distributed to encourage their use by persons at risk for HIV and other sexually transmitted diseases.

Adolescent↗
PubMed1999

Antimitotic drugs cause increased tumorigenicity of multidrug resistant cells.

Taxol and vinblastine are widely and effectively used in the treatment of cancer, but the initial response to chemotherapy is often hampered by the development of multidrug resistant (MDR) cells. The collateral effects of these two antimitotic drugs on MDA-435 human breast carcinoma cells were investigated. When used at concentrations below those required to depolymerize microtubules, both drugs increased cyclin dependent kinase activity and stimulated the MAPK signal transduction pathway. The activity of MAPK pathway elements and cyclin dependent kinases were found to be constitutively elevated in an MDR cell line that was selected with taxol and expresses high levels of P-glycoprotein. The MDR cells maintained these alterations and also overexpressed hyperphosphorylated RB. This was manifested in a higher growth rate for MDR cells in low serum and an increased ability to form colonies in soft agar. These observations suggest that despite high levels of P-glycoprotein in MDR cells, a sufficient amount of taxol remains intracellular to accelerate the cell cycle machinery and activate the MAPK pathway. These alterations accumulate in resistant cells and contribute to a more transformed phenotype. Thus, in addition to the development of MDR, exposure of tumor cells to antimitotic agents produces further cellular changes that may contribute to the failure of chemotherapy.

Antineoplastic Agents↗
PubMed1999

[Pelvic tumoral actinomycosis: a difficult diagnosis. Two case reports].

Two cases of intra-uterine device-associated occlusive pelvic pseudo-tumoural actinomycosis are presented. A pre-operative diagnosis of ovarian carcinoma was considered in both cases and lead to a wide and difficult surgery. Actinomycosis was confirmed by the postoperative histopathologic examination, and the patients were successfully treated with penicillin. The difficulties and limits of the clinical and histopathological diagnosis are exposed. The interest of the pre and intra-operative diagnosis which can avoid an extensive surgery with high morbidity is highlighted.

Actinomycosis↗
PubMed1999

Concurrent paclitaxel and radiation therapy for breast cancer.

Few studies have evaluated the role of concurrent chemoradiation therapy in the management of locally advanced breast cancer. The availability of radiosensitizing chemotherapeutic agents that are effective in breast cancer and the encouraging results achieved by concurrent chemoradiation in other malignancies have prompted us to investigate this approach. Paclitaxel is a promising agent for use with concurrent radiotherapy because of its single-agent efficacy profile and its radiosensitizing effects. A clinical protocol of preoperative paclitaxel and radiation in locally advanced breast cancer is ongoing at our institution to test feasibility, measure pathologic response at mastectomy, and explore association of pathologic response with molecular tumor markers. Initially, the study was designed to test weekly paclitaxel at a dose of 60 mg/m2 during radiation therapy, delivered 5 days a week at 200 cGy fractions to a total dose of 50 Gy over 5 weeks. Due to severe skin toxicity in the first two patients, the protocol was amended to change the scheduling of paclitaxel to 30 mg/m2 twice weekly and to reduce the radiation to 180 cGy fractions to a total dose of 45 Gy, delivered 5 days a week over 5 weeks. Presently, 13 patients have been accrued; preliminary data indicate good tolerance to twice-weekly paclitaxel, and four of eight evaluable patients have achieved pathologic response (one patient who received the weekly regimen and three who received the twice-weekly regimen). In addition, sequential fine-needle aspirations of palpable breast cancers were obtained in patients enrolled in a parallel study of preoperative single-agent paclitaxel (200 mg/m2 every 2 weeks, for a total of four cycles before breast surgery). Preliminary results suggest that a steep increase in the mitotic index occurs during the first day after paclitaxel administration and plateaus between the second and the third day, then decreases to pretreatment values. The peak apoptotic index occurs at approximately 72 hours after paclitaxel administration and decreases at approximately 98 hours. These initial findings suggest that twice-weekly dosing of paclitaxel may optimize recruitment of cells into the G2/M phase of the cell cycle, the most radiosensitive phase.

Antineoplastic Agents, Phytogenic↗