Normalized pressor responses to angiotensin II following long-term vasopressin supplementation in Brattleboro rats: a possible central site of action.
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Angiotensin II↗
Biomedical subjects
C Rodriguez
Publications and source records attributed to C Rodriguez.
Determination of ephedrines in urine by high-performance liquid chromatography.
An improved high-performance liquid chromatographic method with ultraviolet detection for the simultaneous determination of norephedrine, norpseudoephedrine, ephedrine, pseudoephedrine, methylephedrine and ethylephedrine in urine is described. The six substances were separated on a reversed-phase column with phosphate buffer-triethylamine (pH 5.5) as the mobile phase. The linearity and reproducibility were satisfactory for the levels usually found in urine (1-30 micrograms/ml).
Chromatography, High Pressure Liquid↗
Quantitative reduction of MTT by hearts biopsies in vitro is an index of viability.
The aim of this study is to evaluate the use of tetrazolium reductase (TR) activity as an indicator of myocardial viability in an isolated arrested pig heart biopsy model. Methyl Tetrazolium (MTT) is cleaved by an enzyme in the presence of coenzymes NAD, NADP. Cleavage yields a highly colored formazan product which is DMSO soluble. Efficient bioreduction of MTT has been investigated with heart biopsies. The relationship between MTT reduction and (1) oxygen consumption (r = 0.96, P < 0.001), (2) the sum of the adenine nucleotide levels (r = 0.87, P < 0.001) and (3) localization of coloration, has been established. The use of MTT in colorimetric assays offers high sensitivity. MTT reduction is a valid method. It is rapid and reproducible, and can be used as an indicator of myocardial viability. The MTT test has been used to rapidly compare the effect of different cardioplegic solutions (St Thomas and improved St Thomas) on hypothermic cardiac preservation. Significant differences have been established between the two solutions (P < 0.01).
Adenine Nucleotides↗
The evolutionary history of Drosophila buzzatii. XXVII. Thorax length is positively correlated with longevity in a natural population from Argentina.
The correlation between body size and longevity was tested in an Argentinian natural population of Drosophila buzzatii. Mean thorax length of flies newly emerging from rotting cladodes of Opuntia vulgaris was significantly smaller than that of two samples of flies caught at baits. The present results which might be interpreted as directional selection for longevity favoring larger flies are in agreement with previous results achieved in a Spanish natural population of D. buzzatii. Flies emerging from different substrates showed significant differences in thorax length, suggesting that an important fraction of phenotypic variance can be attributed to environmental variability. However, laboratory and field work in different populations of D. buzzatii showed a significant genetic component for thorax length variation.
Animals↗
Expression of P-glycoprotein and anionic glutathione S-transferase genes in non-Hodgkin's lymphoma.
Non-Hodgkin's lymphomas (NHL) are usually sensitive to chemotherapy. A certain percentage of patients are primarily or subsequently resistant to chemotherapeutic agents. Several biological mechanisms are implicated in this phenomenon, including multidrug resistance (mdr1) and glutathione S-transferase (GST pi). We investigated these two systems, using dot blot analysis, in 41 patients who presented NHL with advanced disease. There were 15 patients with low grade, 22 with intermediate grade, and 4 patients with high grade using the Working Formulation for Clinical Usage. Twenty-five patients had not been previously treated and 16 had been treated, including 13 with refractory disease. Eleven out of 25 (44%) patients overexpressed mdr1 mRNA at diagnosis as compared to 6/16 (38%) in relapse, corresponding to 6/13 (46%) refractory patients. Nine out of 25 (36%) patients overexpressed GST pi mRNA at the time of diagnosis, and 6/16 (50%) in relapse. These data indicate that overexpression of these two messengers is not acquired after treatment in NHL. Furthermore, there is no relationship between the stage or histological grade and the overexpression of these two markers. This study shows that mdr1 and GST pi gene expressions are independent of one another. With regard to the clinical response, our results also demonstrated a higher level of treatment failure in the group co-expressing the two transcripts, 6/8 (75%) patients died in progressive disease as compared to 9/15 (60%) patients without overexpression, and 2/8 (25%) vs 6/15 (40%) responded to treatment. On the other hand, overexpression of only one of the two mRNAs did not allow us to observe a difference in the clinical response. Since it seems that coexpression of the mechanisms of resistance present a better clinical impact, it would be of interest to analyse simultaneously different mechanisms involved in the resistance phenomenon in NHL.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Gender-associated differences in the development of 5-aminolevulinate synthase gene expression in the harderian gland of Syrian hamsters.
The mRNA levels for aminolevulinate synthase (ALV-S), the rate-limiting enzyme in porphyrin synthesis, were studied in male and female Syrian hamsters during postnatal development. Sex-associated differences in the expression of ALV-S gene were evident at the end of the third week of postnatal development. Serum levels of luteinizing hormone (LH), testosterone, cortisol, thyroid hormones and insulin-like growth factor were also studied in order to correlate their concentrations with the mRNA levels for ALV-S. Among these hormones, serum LH levels showed a positive correlation with the ALV-S mRNA levels. However, the expected negative correlation with testosterone levels was not clearly observed. Thus, in order to test the effects of testosterone on ALV-S gene expression, 11-day-old male and female Syrian hamsters and adult female hamsters were injected with 50 micrograms of testosterone for 4 days. Testosterone administration decreased the levels of ALV-S mRNA in the adult females but did not influence those of young females. The possible explanation for the insensitivity to testosterone during these postnatal stages might involve the maturational state of androgen receptors in the Harderian glands.
5-Aminolevulinate Synthetase↗
Nasal continuous positive airway pressure in patients with COPD in acute respiratory failure. A study of the immediate effects.
The aim of this study was to assess the effect of nasal continuous positive airway pressure (CPAP) breathing on patients with COPD when they are in respiratory failure during acute episodes of the disease. We studied 15 male patients with COPD who were in acute, unstable condition, without mechanical ventilatory support, before and during 4 h of nasal CPAP. The respiratory rate decreased (initial, 30 +/- 6; final, 25 +/- 6; p < 0.001), as did the subjective sensation of dyspnea (initial Borg index, 3 +/- 3; final, 2 +/- 2; p < 0.05). A significant decrease in the average PaCO2 (before, 73 +/- 10 mm Hg; after, 61 +/- 9 mm Hg; p < 0.001) and a significant increase in the PaO2 (before, 57 +/- 13 mm Hg; after 64 +/- 14 mm Hg; p < 0.05) were also observed. Nasal CPAP was generally well tolerated. According to these results, nasal CPAP should be considered as a possibility for treatment in patients with COPD who are in acute respiratory failure, in order to avoid mechanical ventilation.
Acute Disease↗
Prevention of seroma formation after dissection of musculocutaneous flaps.
Dissection of musculocutaneous flaps is uniformly followed by the formation of seroma if drains are not used. Drains can be colonized and form deep tissue infection if left in place for a long time. In this study we investigated whether talc poudrage could prevent the formation of seroma following dissection of the latissimus dorsi muscle in a canine model. Twelve mongrel dogs were randomized into two groups. Group 1 (n = 6) underwent dissection of the left latissimus dorsi muscle which was rotated as a pedicle flap into the left chest through a second intercostal space thoracotomy. The wound was closed in layers without drains. Group 2 (n = 6) had the same procedure, but before closure of the wound, USP talc was applied to the tissues. All animals received cefazolin (500 mg) Q8h for 48 hours perioperatively. Animals were followed for 1-5 months. Wounds with fluctuation were aspirated as many times as necessary and the amount of fluid was recorded. All Group 1 animals developed seromas, in contrast, only one animal in group 2 had a seroma. There was a significant difference in the amount of fluid aspirated for each animal between the two groups (280 +/- 80 in group 1 vs 25 +/- 25 ml in group 2, P < 0.05). The total amount of fluid drained in group 1 was 1730 ml, whereas only 150 ml was aspirated in group 2. Group 1 animals required a total of 11 aspirations to control seromas, in contrast, only one aspiration was needed in group 2. No abscess was identified at postmortem in either group. Based on the results of this study we conclude that talc poudrage can be safely used to minimize seroma formation after dissection of musculocutaneous flaps.
Animals↗
Seroprevalence of HDV and HIV in two populations at risk for infection with HBV in Spain.
We have studied 1765 patients attending our clinic during 1991, with the aim of determining the prevalence of HDV and HIV infection in our country in two populations at risk for parenteral and sexual HBV transmission. A second objective was to determine whether or not HBV-HIV co-infection was associated with a greater risk for HDV. Our findings indicated that sexual transmission of VHD is not common, unlike parenteral transmission, and that there is a significantly greater prevalence of infection with HDV in Chi-square who have the HBsAg complex and are HIV positive.
Female↗
Cytokine network regulating terminal maturation of human bone marrow B cells capable of spontaneous and high rate Ig secretion in vitro.
Human bone marrow (BM) B cells capable of spontaneous and high rate Ig secretion for 14 days in vitro have been described previously. We have shown recently that Ig secretion by these BM cells depends on stromal adherent BM cell-derived factors identified as IL-6 and fibronectin. Our report shows that the endogenous generation of IL-1 beta and TNF-alpha in serum-containing cultures of BM mononuclear cells (BMMC) is also involved in the control of Ig-secreting cells, because their blockade with specific antibodies markedly reduced Ig production. Further experiments revealed that IL-1 beta and TNF-alpha acted by regulating IL-6 production, as can be deduced from the following findings: 1) the inhibition of Ig secretion caused by either anti-IL-1 beta or anti-TNF-alpha antibodies could be reversed by exogenous IL-6; 2) the addition of either of these antibodies inhibited endogenous IL-6 production in BMMC cultures; 3) IL-1 beta plus TNF-alpha, but neither one alone, restored complete IL-6 and Ig production by BMMC in serum-free cultures. Moreover, adherent, but not nonadherent, BM cells were responsible for endogenous IL-1 beta and TNF-alpha secretion. Finally, IL-1 beta plus TNF-alpha induced the production of IL-6, but not of Ig, by adherent BM cells. Neither IL-6 nor Ig production was induced by adding this cytokine combination to nonadherent BM cell cultures, despite the fact that this fraction contained all the Ig-secreting cells. However, the addition of IL-6 restored Ig secretion in this cell fraction. These results suggest that IL-1 beta and TNF-alpha produced by adherent BM cells synergistically induce early IL-6 generation, which, in turn, drives BM B cell producers into the high rate Ig-secreting state.
Adult↗
Female Syrian hamster Harderian gland: development and effects of high environmental temperature and melatonin injections on histology and porphyrin deposits.
We have investigated the development of the Harderian glands of female Syrian hamsters from birth to 8 months of age. The effects of melatonin injections on Harderian gland histology and porphyrin deposits of female hamsters exposed to two different temperatures were also studied. The morphology of the Harderian glands from 30-day-old female hamsters resembled those of sexually mature adult animals. The intraluminal area occupied by porphyrins increased significantly between 20 to 30 days of age. However, the relative number of mast cells per mm2 rose between 30 to 90 days. Both porphyrins and mast cell numbers appeared clearly reduced in the 8-month-old group. Secretory cells characterized by large lipid droplets (type II cells) were not observed. Daily afternoon injections of 25 micrograms of melatonin to female hamsters exposed to 22 degrees C for 14 weeks resulted in the discontinuity of estrous cyclicity, a marked decrease in the intraluminal area occupied by porphyrins, a reduction of the number of mast cells per mm2, and in a marked augmentation of the number of type II cells per mm2. Although the administration of similar dosages of melatonin to hamsters exposed to an environmental temperature of 32 degrees C did not interrupt estrous cycles, a clear reduction of the area occupied by porphyrins was observed. However, the number of mast cells and type II cells per mm2 was unaffected in these animals. Our results suggest that hormones other than ovarian steroids are involved in the regulation of the female hamster Harderian glands. The possible role of melatonin on Harderian gland metabolism is discussed.
Animals↗
Age and food restriction alter the porphyrin concentration and mRNA levels for 5-aminolevulinate synthase in rat Harderian gland.
The effects of age and food restriction on the porphyrin concentration in Harderian glands were studied in male Fisher 344 rats. Harderian gland porphyrin concentrations increased with age; this was statistically significant in 20 month old animals compared with 3 month old animals. Food restriction (by 40%) prevented the age-associated rise in porphyrins; thus, in 20 month old food restricted rats had porphyrin concentrations similar to those found in young animals. In a second experiment, we correlated the age-associated rise in Harderian gland porphyrin concentrations with an increase in mRNA levels for 5-aminolevulinate synthase (ALV-S). Both the porphyrin concentration and ALV-S mRNA rose at 12 and 18 months of age, but decreased by 24 months of age. It is concluded that, a) porphyrin biosynthesis in the Harderian glands increases up to 20 months of age but decreases in rats that are 24 months old, and b) food restriction prevents the porphyrin rise associated with age in the Harderian gland of male Fisher 344 rats.
5-Aminolevulinate Synthetase↗
Behaviour modification in obese subjects with type 2 diabetes mellitus.
We have followed prospectively, 46 obese, type 2 diabetic patients for a 55-week period, in order to evaluate the efficiency of an educational programme based on behaviour modification to enhance weight loss and changes of other cardiovascular risk factors. No patient received pharmacological treatment during the study. At the end of the follow-up the patients obtained an average weight loss of 9.250 kg (range: 0.500-17.500 kg); the BMI was reduced from 34.2 +/- 0.8 kg/m2 to 30.6 +/- 1.1 kg/m2 (P less than 0.01); fasting serum glucose descended from 7.9 +/- 0.4 to 6.1 +/- 0.5 mM (P less than 0.05); SBP (systolic blood pressure) decreased from 145.7 +/- 3 to 126.4 +/- 5.1 mmHg (P less than 0.01); DBP (diastolic blood pressure) decreased from 83.5 +/- 2.5 to 65 +/- 2.6 mmHg (P less than 0.01); triglyceride levels were lowered from 164.5 +/- 12 to 109.7 +/- 10 mg/dl (P less than 0.01); HDL-cholesterol levels increased from 1.27 +/- 0.05 to 1.53 +/- 0.12 mM (P less than 0.01). Serum glucose 2 h after a 75 g glucose oral load decreased from 14.9 +/- 0.6 to 12.7 +/- 0.9 mM (P less than 0.05) on week 35 of follow-up. Twelve patients no longer presented a diabetic curve (8 normal oral glucose tolerance test (OGTT) curves, and 4 impaired glucose tolerance (IGT) curves). No significant changes in the parameters studied were obtained in the group of patients on conventional treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Behavior Therapy↗
The evolutionary history of Drosophila buzzatii. XXIV. Second chromosome inversions have different average effects on thorax length.
We demonstrate a genetic correlation between rearrangements of the second chromosome of D. buzzatii and thorax length, as a measure of body size. The results indicate that 2j and 2jz3 arrangements are correlated with large size, whereas 2st arrangement is correlated with small size. Some inversions (2st and 2jz3) show dominant effects and others (2j/jz3) exhibit overdominance. These results show that at least 25 per cent of body size variation may be accounted for by the studied karyotypes. The possible integration of the genotypic, phenotypic and fitness levels, and also the possible implications to life-history evolution theories, are discussed. These results suggest that, under moderate to high heritability values, some kinds of chromosomal endocyclic and/or balancing selection may be valuable mechanisms for maintenance of body size variation.
Animals↗
Recovery of mononuclear cell subsets after bone marrow transplantation: overabundance of CD4+CD8+ dual-positive T cells reminiscent of ontogeny.
Patients after bone marrow transplantation are immunodeficient for months to years. To understand better the pathogenesis of this immunodeficiency, we studied quantitative reconstitution of blood monocytes, natural killer (NK) cells, T cells, and B cells at 2-22 months post-transplant. The results indicate monocyte and NK counts generally recover within 2 months, followed by CD4-CD8+ T cell, B cell, and finally (after > 1 year) CD4+CD8- T cell numbers. Dual-positive CD4+CD8+ T cells (which were barely detectable in normal adults), CD4-CD8+ T cells and B cells transiently reached supranormal levels during recovery. Both CD4+CD8- and CD4-CD8+ T cells were larger than controls throughout the 2-year follow up. Comparison with neonatal and infant mononuclear cell subsets suggested the reconstitution of CD4+CD8+ T cells and B cells is similar to ontogeny. In contrast, the reconstitution of CD4+CD8- T cells did not resemble ontogeny.
B-Lymphocytes↗
Effects of human chorionic gonadotropin and progesterone administration on porphyrin biosynthesis and histology of the Harderian glands in male and female Syrian hamsters.
We investigated the influence of hCG and progesterone on the control of porphyrin biosynthesis and histology in the Syrian hamster Harderian glands. Castration of male hamsters caused a marked elevation in porphyrin biosynthesis as revealed by the concentrations of porphyrins and the mRNA levels of the porphyrin pathway rate-limiting enzyme, 5-aminolevulinate synthase (ALV-S). Injection of hCG into castrated male hamsters also resulted in a significant increase in both porphyrin concentrations and levels of ALV-S mRNA compared with those in saline-injected castrated hamsters. Type II cells, which are filled with large lipid vacuoles and are characteristic of male phenotype, disappeared after castration, but administration of hCG partially prevented this change. On the other hand, neither administration of hCG nor progesterone implants could increase the very high porphyrin concentrations and ALV-S mRNA levels characteristic of female Syrian hamsters. As in the case of castrated male hamsters, injections of 20 IU hCG to female Syrian hamsters increased the relative number of Type II cells per square millimeter, whereas progesterone administration did not modify the relative number of Type II cells. These results indicate that hCG can modify Harderian gland morphology in both male and female hamsters and can exert a positive control in the expression of ALV-S gene in castrated male hamsters.
5-Aminolevulinate Synthetase↗
Beta-adrenergic and peptide N-terminal histidine and C-terminal isoleucine stimulation of N-acetyl-transferase activity and melatonin production in the cultured rat pineal gland.
The purpose of this investigation was to compare the effect of peptide N-terminal histidine and C-terminal isoleucine (PHI) with that of the beta-adrenergic agonist isoproterenol (ISO) on N-acetyltransferase (NAT) activity and melatonin production in the cultured rat pineal gland. Pineal glands were removed and placed in organ culture containing PHI, ISO, or PHI plus ISO at different dosages, and subsequent changes in NAT activity and melatonin levels were measured. PHI stimulated these parameters in both a time- and dose-dependent manner. Combined treatment with PHI (10(-6) M) and high doses of ISO (either 10(-7) or 10(-8) M) did not potentiate the effect of the peptide in terms of either NAT activity or melatonin levels in the pineal gland. However, at a lower concentration, ISO (10(-9) M) had additive effects to those of PHI in both cultured pineals and medium. The results suggest that PHI modulates melatonin synthesis in the rat pineal gland. Furthermore, stimulation of the pineal with both PHI and ISO demonstrates an additive effect rather than a synergistic action of these compounds. It is presumed that ISO and PHI stimulate pineal melatonin production via separate receptors, but they probably use the same intracellular second messenger, cAMP, to do so. This is the first study showing an effect of the peptide PHI on pineal melatonin production in any vertebrate.
Acetyltransferases↗
Porphyrin metabolism in the harderian glands of Syrian hamsters: in vivo regulation by testicular hormones, lighting conditions, pineal gland, and pituitary hormones.
The porphyrin concentration in the harderian glands of male hamsters subjected to several endocrine manipulations was studied. Prolonged bilateral gonadectomy resulted in a marked increase in harderian porphyrin concentration. This change was not prevented by either pinealectomy or by constant white light exposure. Castrated hamsters exposed to constant red light showed higher porphyrin concentrations than castrated hamsters kept under white light. Among several hormones studied, serum luteinizing hormone and thyroid-stimulating hormone levels were unexpectedly higher in the constant red light exposed group than in the other groups. In order to test whether luteinizing hormone was involved in the postcastrational rise in harderian porphyrins, we administered a potent luteinizing hormone-releasing hormone (LHRH) agonist. The chronic administration of the LHRH agonist resulted in a decrease in serum luteinizing hormone (because it desensitized the LHRH receptors on the gonadotropes) and, consequently, in serum testosterone levels. However, no rise in harderian porphyrin was observed. It is concluded that the absence of testicular hormones might not be the triggering factor involved in harderian porphyrogenesis.
Animals↗