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Biomedical subjects

M Stein

Publications and source records attributed to M Stein.

At least 181 records · Page 10Linked to original sources
PubMed1994

NMR structures of ferredoxin chloroplastic transit peptide from Chlamydomonas reinhardtii promoted by trifluoroethanol in aqueous solution.

The 32-amino acid transit peptide of the unicellular green alga Chlamydomonas reinhardtii ferredoxin has been synthesized and analysed by NMR spectroscopy and circular dichroism. The results show that while the peptide is unstructured in water, it undergoes an alpha-helix formation from residue 3 to 13 in a 30:70 molar-ratio mixture of 2,2,2-trifluoroethanol. The remainder of the peptide is still unstructured in CF3CD2OD/H2O mixtures, but is distributed on a side opposite to a hydrophobic ridge formed by Met5, Phe9 and Val13 on the induced alpha-helix. The NMR structures driven by 2,2,2-trifluoroethanol in aqueous solution, are discussed in terms of potent interactions with the chloroplast envelope and its translocation molecular machinery.

Amino Acid Sequence↗
PubMed1994

Radiation therapy in an elderly African population with Kaposi's sarcoma.

There are no published studies on the efficacy of modern radiation therapy in elderly populations with the endemic African type of Kaposi's sarcoma (AKS). The present retrospective analysis of 20 elderly AKS patients treated by radiotherapy attempts to supply information relevant to the older age group. It demonstrates that excellent symptomatic relief with minimal side effects can be attained and suggests that the role of radiotherapy as the treatment of choice in this particular group should be emphasized.

Africa↗
PubMed1994

Adaptive functioning in children with attention-deficit hyperactivity disorder.

OBJECTIVE: To evaluate the utility of the Vineland Social Adaptive Scale (Vineland) in measuring social adaptive functioning in children with attention-deficit hyperactivity disorder (ADHD). DESIGN: Cross-sectional group comparison. SETTING: Multidisciplinary hyperactivity and learning problem clinic at a tertiary referral center in Chicago, Ill. PARTICIPANTS: One hundred four school-age children with ADHD. INTERVENTION: None. MEASUREMENTS/MAIN RESULTS: The Vineland was administered to the study population. Despite average full-scale IQ scores (mean [+/- SD], 101 +/- 6), the children with ADHD had Vineland standard scores in the borderline to low-average range (73 +/- 14). The discrepancy between the Vineland standard scores and the full-scale IQ scores increased with increasing age and IQ. CONCLUSIONS: Children with ADHD referred to a tertiary attention problem clinic displayed significant social adaptive dysfunctioning on the Vineland. The evaluation of children with ADHD should include assessment of adaptive skills, and treatment planning for children with ADHD should include the identification of social and adaptive deficiencies when therapeutic goals are established.

Adaptation, Psychological↗
PubMed1994

Malignant lymphoma with primary cardiac manifestations: a case report.

This case report describes a 29-year-old black patient presenting with right heart failure secondary to massive lymphomatous cardiac involvement. Additional sites of involvement included mesenteric lymph nodes and the small bowel. Malignant lymphoma with primary cardiac manifestations is very rare and follows an aggressive course. The importance of early diagnosis and commencement of immediate therapy is emphasized.

Adult↗
PubMed1994

Primary cardiac angiosarcoma: a case report and review of therapeutic options.

A 45-year-old black patient presented with right-heart failure. Echocardiography showed a large tumor mass in the right atrium and a debulking procedure was performed. Histological and immunohistochemical studies revealed a high grade angiosarcoma infiltrating the myocardium and extending to the pericardial surface. Metastatic work-up showed no evidence of dissemination. The patient made an uneventful postsurgical recovery and was treated with chemotherapy, consisting of epidoxorubicin and dacarbazin. Following chemotherapy, echocardiographic re-evaluation failed to show any residual tumor in the right atrium. At present, one year following diagnosis, the patient is alive with no evidence of disease. Therapeutic options of primary cardiac angiosarcoma are reviewed.

Heart Atria↗
PubMed1994

Diurnal and acute stress-induced changes in distribution of peripheral blood leukocyte subpopulations.

In this study, we examined hormonal regulation of the distribution profiles of leukocyte subpopulations in the peripheral blood of rats. Flow cytometric analysis revealed significant and selective changes in the numbers and the percentages of peripheral blood leukocyte subpopulations which were a function of diurnal variations in hormone secretion and hormonal changes induced by acute stress. Changes in numbers and percentages of leukocyte subpopulations, which varied with time of day, were similar to changes observed under stress conditions. At the beginning of the rat's active period, and after 1 h of restraint stress, there was a significant reduction in numbers of leukocytes and lymphocytes. This reduction was primarily accounted for by a decrease in numbers of B cells, natural killer cells, monocytes (diurnal study), and helper T cells (diurnal study). There was also a significant decrease in the percentage of lymphocytes which was mirrored by an increase in the percentage of neutrophils in the peripheral blood. Peripheral blood leukocyte numbers were inversely related to plasma corticosterone levels. These results suggest that the endocrine system plays a role in the regulation of immune cell turnover and/or redistribution between immune compartments under conditions of normal daily experiences, namely, the diurnal cycle, and mild acute stress. They also suggest that these effects are selective for certain subpopulations of leukocytes.

Acute Disease↗
PubMed1994

Purification and characterization of pea thioredoxin f expressed in Escherichia coli.

The recently cloned cDNA for pea chloroplast thioredoxin f was used to produce, by PCR, a fragment coding for a protein lacking the transit peptide. This cDNA fragment was subcloned into a pET expression vector and used to transform E. coli cells. After induction with IPTG the transformed cells produce the protein, mainly in the soluble fraction of the broken cells. The recombinant thioredoxin f has been purified and used to raise antibodies and analysed for activity. The antibodies appear to be specific towards thioredoxin f and do not recognize other types of thioredoxin. The recombinant protein could activate two chloroplastic enzymes, namely NADP-dependent malate dehydrogenase (NADP-MDH) and fructose 1,6-bisphosphatase (FBPase), both using dithiothreitol as a chemical reductant and in a light-reconstituted/thylakoid assay. Recombinant pea thioredoxin f turned out to be an excellent catalyst for NADP-MDH activation, being the more efficient than a recombinant m-type thioredoxin of Chlamydomonas reinhardtii and the thioredoxin of E. coli. At the concentrations of thioredoxin used in the target enzyme activation assays only the recombinant thioredoxin f activated the FBPase.

Amino Acid Sequence↗
PubMed1994

Testicular seminoma: 20-year experience at the Northern Israel Oncology Center (1968-1988).

Eighty-four patients with testicular seminoma were treated at the Northern Israel Oncology Center during the years 1968-1988. Using the staging classification of Hussey, 69 patients (82%) had Stage I, eight (10%) had Stage IIA, four (5%) had Stage IIB, one (1%) had Stage IIIA, and two (2%) had Stage IIIB disease. Sixty-nine patients (82%) had classic pure seminoma, nine (11%) had anaplastic seminoma and six (7%) had spermatocytic seminoma. Seventy-four patients (88%) underwent high inguinal orchiectomy and ten (12%) had a scrotal approach. Seventy-five patients (85%) were treated with postoperative irradiation. Stage I patients received 26-30 Gy to the paraaortic and ipsilateral pelvic lymph nodes. Stage IIA patients were treated in the same manner with a boost to the involved lymph nodes. With a mean follow-up of 97 months, 65 patients (77%) are alive and well with no evidence of disease, 7 patients (8%) are dead due to disease progression. The 5-, 10-, 15-, and 20-year actuarial survival for all patients was 90%, and for early stage patients 94%. Eight patients (14%) relapsed; 3 of them were salvaged by chemotherapy. Serious side effects of irradiation included lethal respiratory failure due to bleomycin-induced pulmonary fibrosis in one patient, peptic ulcer in three patients, hydronephrosis due to paraureteral fibrosis in one patient and recurrent paralytic ileus in one patient. Eight patients (10%) developed nine second cancers, three of them within the previous radiation field.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intracardiac mass as the initial manifestation of metastatic germ cell tumor.

Cardiac metastases as initial presentation of disseminated germ cell tumors have rarely been reported. The hematogenous route is believed to be the most common pattern of dissemination by germ cell tumour, mainly to the lung, central nervous system and liver. We report a 33-year-old patient with embryonal cell carcinoma who presented with an intraatrial metastatic mass as the initial manifestation of metastatic disease.

Adult↗
PubMed1994

Penile gangrene associated with chronic renal failure: report of 7 cases and review of the literature.

Distal penile gangrene associated with renal failure is a rare entity with only 3 cases reported in the literature. Certain physiological abnormalities are commonly found in association with this condition, including secondary hyperparathyroidism, diabetes and peripheral vascular disease. We report our experience with 7 patients who presented with this condition. All patients had end stage renal disease with 5 on hemodialysis, 1 on peritoneal dialysis and 1 with a functioning cadaveric renal transplant. Six patients had diabetes mellitus and all had derangements of the calcium and phosphate metabolism, with the calcium-phosphorus product being greater than 70. Five patients were treated expectantly with resolution of gangrene in 2 and stable disease in 3. Three of the 5 patients managed expectantly and both patients treated with penectomy died of unrelated causes within 3 months. We conclude that there is no advantage to aggressive surgical treatment of penile gangrene associated with renal failure, since the outcome is the same. The overall mortality for this group is high due to associated co-morbid disease regardless of the type of treatment. Furthermore, subtotal parathyroidectomy is not indicated, since spontaneous improvement and mortality rates reported in our series were similar to those of previously reported cases. Expectant management of affected patients affords the best treatment.

Aged↗
PubMed1994

The effects of intraurethral lidocaine anesthetic and patient anxiety on pain perception during cystoscopy.

Despite current practice there is no evidence to demonstrate the efficacy of intraurethral lidocaine gel as an anesthetic for rigid cystoscopy. To evaluate the usefulness of lidocaine in decreasing pain associated with cystoscopy, we performed a prospective, randomized, controlled, double-blind study comparing lidocaine gel with a water based lubricant. The effects of pre-procedure anxiety and prior experience with cystoscopy on pain perception were also evaluated. Physician perception of pain experienced by the patient was compared with the actual pain experienced. We found no decrease in pain perception in men or women following lidocaine gel instillation with a 5 or 10-minute dwell time compared to instillation of the plain lubricant. Increased preprocedure anxiety correlated with increased pain perception in women. Personal experience with prior cystoscopic procedures significantly decreased the current pain perception in men. Physicians underestimated the patient pain perception in all groups. Overall, we found the use of lidocaine gel to be of no benefit in routine rigid cystoscopy. Lowering pre-procedure anxiety may decrease the amount of pain perceived by women but not by men.

Adult↗
PubMed1994

Bladder distention therapy for symptomatic relief of frequency and urgency: a ten-year review.

OBJECTIVE: A retrospective review was undertaken to determine the efficacy of bladder distention therapy for the treatment of frequency and urgency, and to determine the relative value of prolonged versus short duration distention therapy. METHOD: Prolonged bladder distention therapy was performed on 14 patients and short duration distention on 8 patients over a ten-year period. Indications for the procedure included severe urgency, frequency, and incontinence from a variety of etiologies. RESULTS: Five of 14 patients (18 distentions, 2 bladder ruptures) who had prolonged distention, and 3 of 8 patients (9 distentions, 1 bladder rupture) who had short duration distention experienced symptomatic relief on follow-up (p > 0.7). Since there was no difference between the prolonged and short duration groups, the results were combined to yield 8 of 27 successful distentions (30%) in 8 of 22 patients (36%). All patients with detrusor hyperreflexia failed distention therapy. Complications included 3 cases of bladder rupture, 2 cases of urinary retention, and 1 case of urethral stricture. The rates of bladder rupture were identical in both groups (11%). CONCLUSIONS: The use of prolonged bladder distention therapy has no role in the treatment of detrusor hyperreflexia, and only limited success in the symptomatic relief of severe urgency, frequency, and incontinence of other etiologies. Equal efficacy of prolonged and short duration distention therapy would tend to favor the use of short duration distention to reduce possible anesthesia complications and cost.

Adult↗
PubMed1994

BCG-induced granuloma formation in murine tissues.

BCG infection of mice provides a convenient model to study natural and cellular immunity to mycobacteria and the mechanisms of granuloma formation and repair. We have used a range of macrophage (M phi) membrane molecules and secretory products to investigate resident M phi-pathogen interactions and T lymphocyte-dependent recruitment and activation of M phi in different tissues of immature, normal adult and gamma interferon deficient animals. In situ hybridization (ISH), RT-PCR and immunocytochemical analysis of M phi gene and product expression have been correlated with in vitro study of endocytic and secretory activity in which biogel polyacrylamide bead-elicited peritoneal M phi are exposed to Th1 and Th2 cytokines, LPS, BCG and other stimuli. The role of resident and newly recruited M phi responding to BCG in liver, spleen, lung and brain has been defined by means of antigen markers expressed by M phi (F4/80, 7/4, CR3, macrosialin, sialoadhesin and scavenger receptor) and/or T and B lymphoid cells (MHC Class II, CD4, CD8, B220). Heterogeneity in M phi secretory activity was revealed by ISH analysis of lysozyme, TNF-alpha, IL-1 IL-6 and MCP-1, by in vitro assay of NO and superoxide anion production, and by RT-PCR studies of Th1 (interferon gamma) and Th2 (IL-4, IL-13, IL-10) lymphokine mRNA in tissues. Our studies confirm the importance of interferon gamma as a critical mediator of host resistance to mycobacterial infection and raise intriguing questions in regard to T cell and M phi functional heterogeneity in distinct tissue microenvironments.

Animals↗
PubMed1994

Early and longitudinal evaluations of treated infants and children and untreated historical patients with congenital toxoplasmosis: the Chicago Collaborative Treatment Trial.

Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were referred to our study group. A uniform approach to evaluation and therapy was developed and is described herein along with the clinical characteristics of these infants and children. In addition, case histories that illustrate especially important clinical features or previously undescribed findings are presented. Factors that contributed to the more severe disabilities included delayed diagnosis and initiation of therapy; prolonged, concomitant neonatal hypoxia and hypoglycemia; profound visual impairment; and prolonged, uncorrected increased intracranial pressure with hydrocephalus and compression of the brain. Years after therapy was discontinued, three children developed new retinal lesions (without loss of visual acuity when therapy for Toxoplasma gondii was initiated promptly), and three children experienced a new onset of afebrile seizures. Most remarkable were the normal developmental, neurological, and ophthalmologic findings at the early follow-up evaluations of many--but not all--of the treated children despite severe manifestations, such as substantial systemic disease, hydrocephalus, microcephalus, multiple intracranial calcifications, and extensive macular destruction detected at birth. These favorable outcomes contrast markedly with outcomes reported previously for children with congenital toxoplasmosis who were untreated or treated for only 1 month.

Animals↗
PubMed1994

Clinically significant mucosal candidiasis resistant to fluconazole treatment in patients with AIDS.

Eight cases of severe mucosal candidiasis in patients with AIDS who were taking fluconazole at a dosage of 400-800 mg/d are described. Candida albicans alone or in conjunction with Torulopsis glabrata or Candida stellatoidea was isolated from each patient. In vitro susceptibility testing demonstrated resistance to fluconazole in all eight cases. All tested isolates were susceptible to amphotericin B, and six of eight isolates tested were susceptible to itraconazole. All individuals were severely immunocompromised (CD4 lymphocyte counts: mean, 15/mm3; range, 6-39/mm3) and had been receiving prophylaxis with fluconazole for a mean of only 3 months (range, 1-7 months). The occurrence of candidal mucositis in patients receiving high doses of fluconazole is a matter of concern that requires further study in regard to the causes, prevention, and treatment of the disease.

AIDS-Related Opportunistic Infections↗
PubMed1994

Regional metabolic dependency in obstructive sleep apnea.

Abnormalities of oxygen use occur in obstructive sleep apnea, as do impaired cerebral perfusion and alterations of cerebral function. In this case study, the authors quantitated the local cerebral glucose metabolic rate in two patients with obstructive sleep apnea (one with and one without oxygen supply dependency) and assessed cerebral glucose use by increasing oxygen delivery through passive leg elevation. Obstructive sleep apnea was confirmed by visual analysis of nocturnal pulse oximetry traces in two patients and its severity assessed from the respiratory disturbance index and minimum oxygen saturation. Awake local cerebral glucose metabolic rate (microM/min/100 g) was determined by positron-emission tomography using [18F]-2-Fluoro-2-Deoxy-D-Glucose at baseline and on the following day during passive leg elevation. Conditions otherwise were unchanged. The patient with global oxygen supply dependency exhibited a significant increase in the local cerebral glucose metabolic rate. In contrast, the patient without global supply dependency had no change in the local cerebral glucose metabolic rate. These case studies demonstrate the first evidence of improvement in regional metabolic consumption in response to increased oxygen delivery and in the presence of global oxygen supply dependency.

Adult↗
PubMed1994

Effects of selective type I and II adrenal steroid agonists on immune cell distribution.

Adrenal steroids exert their effects through two distinct adrenal steroid receptor subtypes; the high affinity type I, or mineralocorticoid, receptor and the lower affinity type II, or glucocorticoid, receptor. Adrenal steroids have well known effects on immune cell distribution, and although both type I and II receptors are expressed in immune cells and tissues, few data exist on the relative effects mediated through these two receptor subtypes. Accordingly, we administered selective type I and II adrenal steroid receptor agonists to young adult male Sprague-Dawley rats for 7 days and then measured immune cell distribution in the peripheral blood and spleen. Results were compared with those of similar studies using the naturally occurring glucocorticoid of the rat, corticosterone, which binds both type I and II receptors. The majority of the well characterized effects of adrenal steroids on peripheral blood immune cells (increased neutrophils and decreased lymphocytes and monocytes) were reproduced by the type II receptor agonist, RU28362. RU28362 decreased the numbers of all lymphocyte subsets [T-cells, B-cells, and natural killer (NK) cells] to very low absolute levels. The largest relative decrease (i.e. in percentage) was seen in B-cells, whereas NK cells exhibited the least relative decrease and actually showed a 2-fold increase in relative percentage during RU28362 treatment. Similar to RU28362, the type I receptor agonist, aldosterone, significantly reduced the number of lymphocytes and monocytes. In contrast to RU28362, however, aldosterone significantly decreased the number of neutrophils. Moreover, aldosterone decreased the number of T-helper cells and NK cells, while having no effect on the number of B-cells or T-suppressor/cytotoxic cells. Corticosterone at physiologically relevant concentrations had potent effects on immune cell distribution, which were indistinguishable from those of the type II receptor agonist, RU28362. Taken together, these results indicate that effects of adrenal steroids on immune cell distribution are dependent on the receptor subtype involved as well as the specific cell type targeted. These factors allow for varied and complex effects of adrenal steroids on the immune system under physiological conditions.

Aldosterone↗