Glycosaminoglycan-sulfate as plasma membrane component of pig spermatozoa.

The effect of specific glycosaminoglycan-hydrolyzing enzymes on the ruthenium red staining of pig spermatozoa was studied. Washed spermatozoa were incubated at 35 degrees C in buffer or with neuraminidase 0.5 units/ml, heparinase 0.2 mg/ml, or chondroitinase ABC 2.0 units/ml. After incubation sperm cells were washed, stained with ruthenium red and studied under the electron microscope. Anionic sites in the surface of untreated spermatozoa follow regularly the plasma membrane, but present are numerous processes constituting what has been defined as the glycocalyx. Neuraminidase did not affect the distribution of ruthenium red on the surface of the spermatozoa, but eliminated almost completely the processes of the glycocalyx. Heparinase caused loss of the ruthenium red-stained sites on the membrane surface of pig spermatozoa with less influence on the dense processes of the glycocalyx. A similar loss of ruthenium red-stained sites was observed with nitrous acid treatment. A striking effect of treatment with chondroitinase ABC was the production of a typical acrosome reaction.     

Homogeneously staining region in anthracycline-resistant HL-60/AR cells not associated with MDR1 amplification.

Anthracycline-resistant HL-60/AR cells and their drug-sensitive HL-60/S counterparts were characterized by karyotypic analysis and examined for the overexpression of DNA and mRNA sequences coding for P-glycoprotein (Pgp). The HL-60/S cells were karyotypically stable over a 5-year period of study (1986-1991), except for an additional small Giemsa-positive band noted at 7q22 in cultures harvested in 1987, but not in 1986. This change did not affect drug sensitivity. The drug-resistant HL-60/AR cells examined in 1986, 1987, and 1991 demonstrated a very stable karyotype. The most striking feature was a large homogeneously staining region in the long arm of chromosome 7 (7q11.2), and translocation of the remainder of the long arm to another centromere. Other changes in the HL-60/AR cells included inversion in 9q, partial deletion of the short arm of chromosome 10p, addition of material to the p arm of der(16), loss of chromosome 22, and the appearance of a new marker chromosome. Both HL-60/S and the HL-60/AR cells were found not to amplify DNA or mRNA sequences coding for the Pgp. Thus, although the HL-60/AR cells possess the classical multidrug resistance phenotype and demonstrate a homogeneously staining region near the region of the MDR1 gene, their resistance is due to mechanisms other than those coded for by MDR1.     

Culturable and nonculturable bacterial symbionts in the toxic benthic dinoflagellate Ostreopsis lenticularis.

The toxic benthic dinoflagellate Ostreopsis lenticularis hosts a variety of symbiont bacterial flora. Laboratory cultured Ostreopsis clones require the presence of symbiotic Pseudomonas/Alteromonas bacterial strains for growth and toxicity development. Three culturable bacterial strains associated with Ostreopsis were identified as Pseudomonas/Alteromonas strain 1, Pseudomonas/Alteromonas strain 2 and Acinetobacter. Denaturing gradient gel electrophoresis (DGGE) analyses of extracted Ostreopsis associated bacterial DNAs indicated that there were three culturable and four non-culturable associated bacterial strains. The results presented here are the first report of the presence of unculturable bacterial symbionts in a toxic benthic dinoflagellate. Ostreopsis lost toxicity when exposed to elevated temperatures in the field and laboratory culture and subsequently recovered toxicity at reduced temperatures. Ostreopsis associated culturable Pseudomonas/Alteromonas bacterial strains were significantly reduced in dinoflagellate cultures exposed to elevated temperatures. The decreased toxicity of O. lenticularis exposed to elevated temperatures and their subsequent recovery of toxicity in periods of reduced thermal stress may have resulted from the effects of elevated temperature on the spectrum of culturable and unculturable bacterial species interacting with their Ostreopsis host.     

Exercise test in patients with permanent pacemakers

From June 1988 to June 1990 we studied fifty patients who had implantation of a pacemaker. (31 females and 19 males). All of them underwent stress test with Bruce's protocol. Patients were divided in two groups; pacemaker-independent (PI) and pacemaker-dependent (PD). Over 50% of the patients inhibited the pacemaker with their own rhythm, most of them had sinus dysfunction. Complete A-V block was predominant in PD. The group of PI achieved more mets and had more oxygen consumption. Blood pressure response was similar in both groups.     

The C57BL/10Bg sps/sps mouse: a mutant with absence-like seizures; neurochemical and behavioral correlates

C57BL/10Bg sps/sps mice display behavioral arrest, similar to generalized absence seizures. Compared with the parent strain C57BL/10Bg SPS/SPS, the activities of glutamate decarboxylase (GAD, E. C. 2.6.1.15), GABA aminotransferase (GABA-T, E. C. 2.6.1.19), aspartate aminotransferase (ASP-T, E. C. 2.6.1.1), and glutamate dehydrogenase (GDH, E. C. 1.4.1.3) in whole brain crude supernatant were significantly reduced in the sps/sps mice. Alanine aminotransferase activity (ALA-T, E. C. 2.6.1.2), was not altered in any of the strains, and normalization of GAD, GABA-T and GDH activities by that of ALA-T, further revealed significant differences between the normal strain (SPS/SPS), the heterozygotes (SPS/sps), and behavioral arrest (sps/sps) mice. These results suggest the possible involvement of GABAergic and glutamatergic neurotransmission in the absence-like behavior displayed by sps/sps mice. Open field behavior of C57BL/10Bg sps/sps mice is characterized by periods of marked inactivity which easily distinguish affected homozygotes, from their heterozygotes littermates.     

Rabbit antithymocyte globulin. A 10-year experience in cardiac transplantation

Rabbit antithymocyte globulin, a "custom-made" pan-anti-T-cell antibody produced in rabbits, is currently being evaluated in the United States and may, within several years, become approved by the Food and Drug Administration. Because we have used this agent for induction of immunosuppression for 10 years in cardiac recipients and because the results appear to be more favorable than those obtained with other agents (horse antithymocyte globulin, antilymphocyte globulin, OKT3), we have reviewed our experience. For the purpose of analysis, all non-bridge-to-transplant cardiac recipients have been divided into three groups on the basis of immunosuppression protocol: group I (March 1979 to January 1983), 28 patients treated with rabbit antithymocyte globulin, steroids, and azathioprine; group II (January 1983 to March 1985), 29 patients treated with rabbit antithymocyte globulin, cyclosporine, and steroids; and group III (March 1985 to January 1989), 98 patients treated with rabbit antithymocyte globulin, cyclosporine, steroids, and azathioprine. Actuarial data showed advantage for group III in survival rate (1 year 94%, 2 years 91%, 3 years 88%), freedom from rejection (30% free at 1 year), freedom from infection (50% free at 1 year), freedom from death from rejection (99% free at 1 year), and freedom from death from infection (97% freedom at 1 year). Actuarial survival rates and freedom from death from rejection and infection are comparable for any of our groups with contemporary published data. In the past 3 years, we have had no death from acute rejection or from posttransplant infection. Time-related rates of infection by etiologic agents have shown a significant reduction in early bacterial, viral, and nocardial infections between groups I and III. With rabbit antithymocyte globulin 200 mg intramuscularly every day for 3 days, our current protocol, T-cells are significantly reduced and local and systemic toxicity is almost unnoticeable. A progressively increasing cyclosporine dose along with rapid tapering steroid and maintenance azathioprine immunosuppressive induction appears to be the therapy of choice in cardiac transplantation.     

Nutrition of Honduran mothers/caretakers.

In 1996, the Honduran Ministry of Health conducted a national micronutrient survey of children 12-71 months old, which also included an assessment of the nutrition status of their mothers/caretakers. The 1,126 mothers/caretakers who participated in the survey tended to be short and plump. About 15% of them were at obstetric risk by virtue of their short stature and/or low body weight. About 9% had chronic energy deficiency (CED), but 27% were at least 20% overweight. CED was associated with socioeconomic indicators of poverty. Risk factors for being at least 20% overweight included being over 30 years old, not breast-feeding, having attended no higher than grade 4, 5, or 6 of primary school, coming from a wealthier household, and living in San Pedro Sula or medium-sized cities. Among the women surveyed, 26% of nonpregnant and 32% of pregnant mothers/caretakers were anemic. The likely principal cause of anemia was the low intake of bioavailable iron from food and, in some cases, excessive iron loss associated with intestinal parasites, especially hookworm. Only 50% of the mothers/caretakers participating in this study had received iron during their last pregnancy, and just 13% had received postpartum vitamin A. The results highlight the need to develop and implement an effective program to control iron deficiency anemia in women of reproductive age, including by fortifying such widely consumed foods as processed wheat and maize flour and by routinely administering iron supplements to high-risk groups. Postpartum vitamin A supplementation should be encouraged to protect both the mother and newborn infant against vitamin A deficiency.     

Tentorial dural arteriovenous fistula obliterated using the petrosal approach

BACKGROUND: Tentorial dural arteriovenous fistulas (AVFs) are uncommon lesions usually treated surgically using a subtemporal exposure with division of the tentorium. This exposure requires significant retraction of the temporal lobe and has the possibility of significant arterialized venous bleeding if a draining vein is accidentally cut during division of the tentorium. Skull base surgical techniques may provide alternate approaches for the surgical treatment of tentorial dural AVFs. METHODS: A tentorial dural arteriovenous fistula supplied by the tentorial artery and drained by the petrosal vein was exposed and obliterated using the petrosal (subtemporal-presigmoid) approach. RESULTS: The petrosal approach allowed the exposure and division of the superior petrosal sinus and tentorium with direct visualization of the supratentorial and the infratentorial compartments, avoiding accidental damage to the draining veins. The dural fistula was easily obliterated after its venous drainage was interrupted and the tentorial artery occluded. CONCLUSIONS: Tentorial dural AVFs can be safely treated with interruption of the venous drainage. The exposure can be enhanced with a petrosal approach, decreasing the possibility of uncontrolled bleeding during the procedure.     

Lack of hemoglobin response to iron supplementation in anemic mexican preschoolers with multiple micronutrient deficiencies

BACKGROUND: In developing countries, incomplete resolution of anemia with iron supplementation is often attributed to poor compliance or inadequate duration of supplementation, but it could result from deficiencies of other micronutrients. OBJECTIVE: Our objective was to assess children's hematologic response to supervised, long-term iron supplementation and the relation of this response to other micronutrient deficiencies, anthropometry, morbidity, and usual dietary intake. DESIGN: Rural Mexican children aged 18-36 mo (n = 219) were supplemented for 12 mo with either 20 mg Fe, 20 mg Zn, both iron and zinc, or placebo. Children were categorized as iron-unsupplemented (IUS; n = 109) or iron supplemented (IS; n = 108). Hemoglobin, hematocrit, mean corpuscular volume, mean cell hemoglobin, plasma concentrations of micronutrients that can affect hematopoiesis, anthropometry, and diet were assessed at 0, 6, and 12 mo; morbidity was assessed biweekly. RESULTS: At baseline, 70% of children had low hemoglobin (相似文献