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Biomedical subjects

M Stein

Publications and source records attributed to M Stein.

At least 91 records · Page 5Linked to original sources

Heavy-metal regulation of thioredoxin gene expression in chlamydomonas reinhardtii

Heavy metals are highly toxic compounds for cells. In this report we demonstrate that the expression of Chlamydomonas reinhardtii thioredoxins (TRX) m and h is induced by heavy metals. Upon exposure of the cells to Cd and Hg, a strong accumulation of both messengers was observed. Western-blot experiments revealed that among these two TRXs, only TRX h polypeptides accumulated in response to the toxic cations. A biochemical analysis indicated that heavy metals inhibit TRX activity, presumably by binding at the level of their active site. Sequence analysis of the C. reinhardtii TRX h promoter revealed the presence of cis-acting elements related to cadmium induction. The origins and purposes of this regulation are discussed. Our data suggest, for the first time to our knowledge, a possible implication of TRXs in defense mechanisms against heavy metals.

Journal Article↗

Enterohemorrhagic Escherichia coli O157:H7 produces Tir, which is translocated to the host cell membrane but is not tyrosine phosphorylated.

Intimate attachment to the host cell leading to the formation of attaching and effacing (A/E) lesions is an essential feature of enterohemorrhagic Escherichia coli (EHEC) O157:H7 pathogenesis. In a related pathogen, enteropathogenic E. coli (EPEC), this activity is dependent upon translocation of the intimin receptor, Tir, which becomes tyrosine phosphorylated within the host cell membrane. In contrast, the accumulation of tyrosine-phosphorylated proteins beneath adherent EHEC bacteria does not occur, leading to questions about whether EHEC uses a Tir-based mechanism for adherence and A/E lesion formation. In this report, we demonstrate that EHEC produces a functional Tir that is inserted into host cell membranes, where it serves as an intimin receptor. However, unlike in EPEC, in EHEC Tir is not tyrosine phosphorylated yet plays a key role in both bacterial adherence to epithelial cells and pedestal formation. EHEC, but not EPEC, was unable to synthesize Tir in Luria-Bertani medium but was able to secrete Tir into M9 medium, suggesting that Tir synthesis and secretion may be regulated differently in these two pathogens. EHEC Tir and EPEC Tir both bind intimin and focus cytoskeletal rearrangements, indicating that tyrosine phosphorylation is not needed for pedestal formation. EHEC and EPEC intimins are functionally interchangeable, but EHEC Tir shows a much greater affinity for EHEC intimin than for EPEC intimin. These findings highlight some of the differences and similarities between EHEC and EPEC virulence mechanisms, which can be exploited to further define the molecular basis of pedestal formation.

Adhesins, Bacterial↗

Early prediction of neurological outcome after falls in children: metabolic and clinical markers.

Falls are the foremost reason for non-fatal injuries and are second only to motor vehicle accidents in causing accidental death. The purpose of this study was to identify the clinical and metabolic predictors of the outcome of head injury caused by falls from a height. Medical records of 61 children who had been admitted to the paediatric intensive care unit from 1990 to 1993 after falling from a height were reviewed retrospectively. Outcomes were categorised as good, moderate, severe, and poor. Glasgow coma scores, pupillary responses, brain oedema, and midline shift are significantly associated with poor outcome (p < 0.05). Metabolic markers associated with poor outcome included hyperglycaemia and hypokalaemia. Children with a poor outcome had, at admission, significantly higher glucose concentrations compared with children with good outcomes (mean SD): 20.0 (7.1) v 9.31 (4.0) mmol/l, p < 0.01), and lower potassium concentrations compared with children with good, moderate, and severe outcomes (mean (SD): 2.8 (0.4) v 3.7 (0.4) mmol/l, p < 0.001, 3.5 (0.3) mmol/l, p < 0.01, and 3.41 (0.3) mmol/l, p < 0.05, respectively). These findings allow for an early allocation of effort and resources to children injured from such falls.

Accidental Falls↗

Autologous keratinocytes cultured on benzylester hyaluronic acid membranes in the treatment of chronic full-thickness ulcers.

Keratinocytes were obtained from three patients with chronic full-thickness ulcers of different aetiologies. The cells were isolated, cultured and then seeded on to a membrane composed of benzylester hyaluronic acid. Once the keratinocytes had become subconfluent, the keratinocyte-containing matrix sheets were then applied as autologous grafts to the patients' ulcers. Results indicate that autologous grafting of keratinocytes cultured on benzylester hyaluronic acid membranes provides improved graft handling, reduces total time required for tissue cultivation and enhances cellular vitality because of the possibility of grafting at a subconfluent non-differentiated stage.

Aged↗

Hand preference as related to development and behavior in infancy.

55 healthy infants were assessed for their developmental and behavioral patterns at the age of 9 mo. Hand preference was assessed at 20 mo. of age. The distribution of hand preference showed 12 were right-handed, 11 left-handed and 23 ambidextrous. This distribution appears shifted more to the left than that reported for older children. Although their data were based on different tests not appropriate for 9-mo.-old infants, ambidexterity appeared to reflect part of the hand-preference continuum. No significant relationship between hand preference and developmental attainments was noted. Perhaps a larger sample would provide a clear developmental behavioral pattern and hand preference in infancy.

Child Development↗

Sexual practices in a cohort of US women with and without human immunodeficiency virus. HERS Study. HIV Epidemiology Research Study.

OBJECTIVES: To compare the frequency and pattern of sexual activities of women infected with human immunodeficiency virus (HIV) relative to uninfected women at the time of enrollment into a multisite cohort study. METHODS: The HIV Epidemiology Research Study (HERS) is a prospective study following 873 HIV-infected and 438 HIV-uninfected women. The baseline protocol included interviews about sexual practices, sociodemographic information, and drug and alcohol use, as well as clinical and laboratory studies. Multiple logistic regression models estimated differences between infected and uninfected women in relation to sexual activity and practice. RESULTS: 77% of infected women and 89% of uninfected women reported at least one sexual partner in the six months before study entry. Among sexually active women, specific practices varied little by HIV serostatus, with the exception of oral sex, which was more frequently performed and received by uninfected women. Despite the high prevalence of sexual activity, infected women were 2.5 times as likely not to have had any recent sexual partners as uninfected women (95% CI = 1.77-3.44). CONCLUSIONS: Women who decrease or altogether stop engaging in sexual partnerships may benefit from direct counseling in relation to underlying loss of sexual affection.

Adolescent↗

Factors contributing to physicians' success in the advanced trauma life support program in Israel.

BACKGROUND: Since its introduction in Israel, more than 4,000 physicians from various specialties and diverse medical backgrounds have participated in the Advanced Trauma Life Support course. OBJECTIVES: To analyze the factors that influence the success of physicians in the ATLS written tests. METHODS: A retrospective study was conducted of 4,475 physicians participating in the Israeli ATLS training program between 1990 and 1996. Several variables in the records of these physicians were related to their success or failure in the final written examination of the course. RESULTS: Age, the region of medical schooling, and the medical specialty were found to significantly influence the successful completion of the ATLS course. CONCLUSIONS: Physicians younger than 45 years of age or with a surgical specialty are more likely to graduate the ATLS course. The success rate could be improved if the program's text and questionnaires were translated into Hebrew.

Adult↗

Medics in the Israel Defense Forces and their experience in trauma care during peacetime.

BACKGROUND: In the military environment it is the medics who usually provide the initial care of mass casualties in the field. OBJECTIVES: To determine the number of incidents of trauma encountered by medics in the Israel Defense Forces during peacetime, and to ascertain the role of these medics in providing primary trauma care to the victims. METHODS: A retrospective questionnaire, reviewing the activities of medics in treating injured trauma victims, was distributed to medics who were in service for at least 2 years after their professional training. RESULTS: Of the 128 responding medics, 87 (68%) had actively participated in the treatment of trauma victims under various circumstances. The average number of trauma events was 1.2 events over a period of 2 years per combat medic, and 0.7 for medics stationed in rear units. Their activities included insertion of numerous intravenous fluid lines (57% of medics), assistance in intubations (37%), tube thoracostomies (23%), insertions of central catheters (14%) or orogastric tubes (28%), and manual ventilations (41%). CONCLUSION: Since it is difficult to increase the level of practical experience in dealing with trauma within the military framework, new techniques should be applied to improve the trauma training.

Adult↗

Primary trauma care experience of army reserve combat medics: is a new approach needed?

Combat medics play a significant role in any fighting unit. In recent years, during times of peace and low-intensity military conflicts, as well as in operations other than war, reserve combat medics have been challenged to treat major casualties in the field. Although this work requires important manual skills, the medics perform basic treatment maneuvers that are not necessarily for saving of lives. A sample survey of reserve combat medics revealed that most (70%) were engaged in medical care for trauma victims during their regular and reserve service. Many (32.5%) were involved in incidents with multiple casualties. These incidents included seriously injured victims, with 39.2% of the medics being involved with air evacuation and 44.4% with fatalities. Not all medics are exposed to major trauma, but for those who are, the numbers of patients per medic is not large. Therefore, the need to educate the medics in cognitive, and more importantly, in manual skills, is obvious. Suggestions for the means to do so are provided.

Clinical Competence↗

Quantification of mitral and tricuspid regurgitation by the proximal flow convergence method using two-dimensional colour Doppler and colour Doppler M-mode: influence of the mechanism of regurgitation.

In patients with mitral (n=77: organic=49, functional=28) and tricuspid regurgitation (n=55: functional=54) quantified by angiography, the temporal variation of the proximal flow convergence region throughout systole was assessed by colour Doppler M-Mode, and peak and mean radius of the proximal isovelocity surface area for 28 cm/s blood flow velocity were measured. Additionally, the peak radius derived from two-dimensional colour Doppler was obtained. About 50% of the patients with mitral and tricuspid regurgitation showed a typical temporal variation of the flow convergence region related to the mechanism of regurgitation. The different proximal isovelocity surface area radii were similarly correlated to the angiographic grade in mitral and tricuspid regurgitation (rank correlation coefficients 0.55-0.89) and they differentiated mild to moderate (grade < or =II) from severe (grade > or =III) mitral and tricuspid regurgitation with comparable accuracy (82-96%). However, moderate mitral regurgitation due to leaflet prolapse in two patients was correctly classified by the mean M-mode radius and overestimated by both peak radii. Only half of the patients showed a typical variation of the flow convergence region related to the mechanism of regurgitation. The different proximal isovelocity surface area radii were suitable to quantify mitral and tricuspid regurgitation in most patients. However, in mitral regurgitation due to leaflet prolapse the use of the mean M-mode radius may avoid overestimation.

Adult↗

[Changes in structure and process components of trauma care in emergency departments in Israel--Part I].

In recent years there have been tremendous efforts to improve primary trauma care. The Ministry of Health and other authorities have invested in new trauma facilities in various hospitals. A nationwide survey with regard to structure and function of emergency departments was carried out. Compared to a similar survey conducted in 1992, significant progress in quality and quantity of equipment at various emergency departments was demonstrated. However, there are still differences between various hospitals. A drive to standardize trauma care will undoubtedly contribute to improvement in care of the injured.

Emergencies↗

Health services use by urban women with or at risk for HIV-1 infection: the HIV Epidemiology Research Study (HERS).

OBJECTIVE: To characterize health services use by urban women with or at risk for HIV-1 infection enrolled in a prospective multicenter study. METHODS: 1310 women 16 to 55 years of age who were at risk for HIV-1 infection were recruited between April 1993 and January 1995 at four urban centers (Baltimore, Maryland; The Bronx, New York; Detroit, Michigan; and Providence, Rhode Island). HIV-1-seropositive women without AIDS-defining illness were oversampled in a ratio of 2:1 in comparison with HIV-1-seronegative women. At a baseline study visit, the women received physical and laboratory examinations, including CD4+ counts, and were interviewed regarding HIV risk behavior, health services use, and clinical data. RESULTS: 863 women were HIV-1-seropositive and 430 were HIV-1-seronegative. Fifty-two percent of the women reported injection drug use (IDU) since 1985, and 48% acquired HIV through sexual contact. Seventy-seven percent were African American, 23% were white, and 16% were Hispanic. The median age was 35 years. HIV-seronegative women were significantly less likely to have health insurance (19%) than were HIV-seropositive women (30%; p < .001). Among the HIV-seropositive women, 68% had CD4+ cell counts of <500/microl, and 64% were asymptomatic. Sixty-four percent of the HIV-seronegative women had had an outpatient hospital visit in the past 6 months, as had 86% of HIV-seropositive women (p < 0.001). Hospitalization in the past 6 months was also higher in HIV-seropositive women (22% vs. 12%; p < .001). Despite heavy use of health services, only 49% of women with CD4+ counts of <200/microl reported current use of antiretroviral therapy, and only 58% reported current use of Pneumocystis carinii pneumonia (PCP) prophylaxis. Among HIV-seropositive women, and after adjusting for CD4+ count, HIV symptoms, race, and study site, IDUs were significantly less likely to have a regular doctor and a recent outpatient visit and more likely to be hospitalized and use the emergency department (ED) than were non-IDUs. In multivariate analyses of HIV-seropositive persons, African American women had similar access to care and use of antiretroviral therapy and PCP prophylaxis than did white women but were less likely to have an outpatient department visit in the previous 6 months and to be taking PCP and opportunistic infection (OI) prophylaxis. Health services access and use of HIV-related therapies did not significantly differ between Hispanic and white women with HIV infection. CONCLUSION: Although both HIV-seropositive and HIV-seronegative women had high levels of use of medical services, current use of antiretrovirals and OI prophylaxis was low throughout, and IDUs used HIV-related primary health services less and were more likely to receive emergency or episodic care. IDU and African American race were independently associated with decreased use of medical services.

Adolescent↗

[Israel's ATLS program: summary and outlook].

In recent years a vigorous effort has been made to improve quality of primary trauma care in Israel. Advanced trauma life support courses (ATLS) were given to physicians throughout the country, regardless of their specialties. In 7 years 4229 physicians participated in 202 courses with an average success rate of 76%. In the future, issues such as mandatory vs. voluntary training, language barriers, and continuous decline of knowledge should be addressed if momentum is to be maintained.

Curriculum↗

Role of bronchial artery embolization in the management of hemoptysis.

OBJECTIVE: To assess the modern morbidity of hemoptysis and the contribution of therapeutic bronchial artery embolization to its management. METHODS: Medical record review of patients admitted for the treatment of hemoptysis from January 1991 to November 1995 and of patients who had therapeutic bronchial artery embolization from June 1986 to August 1995. Hemoptysis was labeled major or minor. RESULTS: A total of 138 patients were admitted with hemoptysis, 31 with major and 107 with minor hemoptysis. No emergency pulmonary resections were required. Mean follow-up was 13.5 months. Mortality was 29.7% (41/138) but was caused by bronchial bleeding in only 4.3% (6/138). Twenty-six patients underwent therapeutic bronchial artery embolization (mean follow-up [range], 14 months [0.3-69.0 months]). The initial success rate (no further bleeding during the initial admission) was 85% (22/26). The long-term success rate (no further bleeding during follow-up) was 58% (15/26). Only 2 patients with therapeutic bronchial artery embolization died of further hemoptysis. CONCLUSIONS: Hemoptysis signals life-threatening diseases. Therapeutic bronchial artery embolization is a good treatment adjunct to control bronchial bleeding and reduces the need for high-risk emergency lung resections.

Bronchial Arteries↗

Prospective study comparing hyoscyamine, doxazosin, and combination therapy for the treatment of urgency and frequency in women.

Anticholinergics are commonly used for the treatment of frequency, urgency, and urge incontinence in women. Alpha-blockers have been shown to have a modulating effect on bladder smooth muscle but are not commonly used clinically for this indication. To evaluate the clinical effectiveness of each treatment as well as the combination therapy, we performed an open prospective study comparing these agents. Between September 1994 and October 1995, 34 women aged 28-91 (mean age, 62) received either 0.375 mg of sustained-release hyoscyamine twice a day or 2 mg doxazosin QHS prior to being crossed over to the other drug and/or the combination. Symptoms were assessed using an expanded American Urological Association (AUA) symptoms score, which included questions regarding incontinence at completion of each therapeutic phase. Evaluation included 6-channel urodynamics. All three therapies were noted to be effective in reducing AUA symptom scores. By urodynamic evaluation, a greater percentage of patients with increased voiding pressures or decreased compliance responded to doxazosin than hyoscyamine. Side effects were noted to be less prevalent with doxazosin than with the other therapies. There appears to be a significant role for alpha-blockers in the treatment of voiding symptoms in women.

Adrenergic alpha-Antagonists↗