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Biomedical subjects

R Sanchez

Publications and source records attributed to R Sanchez.

At least 73 records · Page 4Linked to original sources
PubMed1996

Sperm selection methods for intracytoplasmic sperm injection (ICSI) in andrological patients.

PURPOSE: To improve the chances of successful in vitro fertilization, spermatozoa have to be separated from semen before insemination. Therefore, sperm preparation methods are of great importance. METHODS: To obtain sufficient numbers of spermatozoa from patients with cryptozoospermia or severe OAT syndrome, only Minipercoll centrifugation and migration-sedimentation (MS) are practicable methods. The present study was performed to compare these two methods with regard to sperm concentration, motility, vitality, morphology, and chromatin condensation. The number of spermatozoa obtained after minipercoll was higher than that after MS, but sperm quality in all parameters examined was clearly better after MS than after Minipercoll. In the second stage of this study, the MS method was used for preparation of the spermatozoa for intracytoplasmic sperm injection (ICSI). RESULTS: Over a period of 13 months, 159 cycles were treated by ICSI. Of 1045 aspirated oocytes, 790 were injected. The fertilization rate was 70.4% of injected oocytes (556 oocytes with clearly visible pronuclei). In 146 cases, embryonic transfer was achieved; 58 patients became pregnant (39.7% per transfer and 36.5% per cycle). CONCLUSIONS: Although the abortion rate was very high (18 women lost their embryos), the results demonstrate that the microinjection method can be successfully used in combination with a MS method for preparation of spermatozoa.

Abortion, Spontaneous↗
PubMed1996

Herpes simplex virus infection in burned patients: epidemiology of 11 cases.

Burned patients suffer significant immunosuppression during the first 3 or 4 weeks after hospitalization. Herpes simplex virus (HSV) infections are commonly seen in immunosuppressed patients and may account for considerable morbidity and some mortality. We studied retrospectively 11 patients with severe burn injury who became infected with HSV. We determined the prevalence of viral infection in this group of patients. Serological testing and viral culture was used to diagnose HSV infection. No general complications appeared in these 11 patients in association with HSV but two patients died of multiorgan failure. Locally, areas of active epidermal regeneration were most commonly affected. Acyclovir therapy was not used and the duration of hospitalization was normal in these 11 patients.

Adult↗
PubMed1996

Paraorbital lesions.

Explore the source record for details and available documents.

Central Nervous System Neoplasms↗
PubMed1996

Leukemia cutis: Darier's sign in a neonate with acute lymphoblastic leukemia.

Infantile leukemia accounts for only 3% of childhood leukemia. Leukemia cutis occurs in 25% to 30% of infants with congenital leukemia and is more frequently associated with acute myeloid leukemia than with acute lymphoblastic leukemia. We describe an infant in whom hyperpigmented macules that developed when the patient was 2 weeks old demonstrated Darier's sign when he was 4 weeks old. Acute lymphoblastic leukemia, early pre-B-cell type, was diagnosed when the patient was 10 weeks old. Examination at that age revealed 1 to 2 cm, firm, mildly tender nodules clustered on the scalp, face, and extremities, less severe involvement of the trunk, and marked induration of the face and eyelids. Darier's sign was elicited from the less infiltrated truncal lesions. Histologic examination revealed a dense monomorphous infiltrate consisting of pleomorphic, undifferentiated cells. No mast cells were revealed by Giemsa staining. This case is to our knowledge the first reported example of leukemia cutis demonstrating Darier's sign.

Humans↗
PubMed1996

[Role of albumins in burnt patients: its efficacy during intensive care. Addendum to the expert guidelines of the Consensus Conference, Paris December 15th 1995].

In the burned patient, the critical threshold over which a correction of hypoalbuminemia is required has not yet been clearly defined. The level of 30 g.L-1 of albumin is usually admitted. According to the extent of the burn, albumin is not indicated in patients with a burn size below 15% of the total body surface. It is essential, from the very beginning of management in patients with a burn size over 50%. Its administration can be postponed to the 8th, 12th or even 24th hour in case of a burn size between 15 and 50%.

Albumins↗
PubMed1996

Intratumoral heterogeneity and inverse correlation between expression of E-cadherin and collagenase type IV in human gastric carcinomas.

We examined the expression of E-cadherin and collagenase type IV in formalin-fixed, paraffin-embedded specimens of human gastric carcinoma by an in situ mRNA hybridization (ISH) technique. The ISH technique revealed intertumoral heterogeneity for expression of E-cadherin and collagenase among 12 cases of early gastric cancer and 13 cases of advanced gastric cancer. In the majority of the tumors, we found an inverse relationship between the reactivities of E-cadherin and collagenase type IV. Specifically, E-cadherin was expressed at higher levels in the center of the neoplasms than in their periphery, whereas collagenase type IV was expressed at a higher level in the periphery (invasive edge) than in the center. Advanced gastric cancers with high levels of expression for collagenase type IV in the periphery had a higher incidence of distant lymph node metastasis than those with low expression. The data show an inverse relationship between E-cadherin (involved in cell-to-cell adhesion) and collagenase type IV (involved in invasion) in different zones of human gastric carcinoma and suggest that the relative expression of these independent genes may be involved in local invasion and metastasis.

Base Sequence↗
PubMed1996

Non-modulating hypertension: evidence for the involvement of kallikrein/kinin activity associated with overactivity of the renin-angiotensin system. Successful blood pressure control during long-term Na+ restriction.

BACKGROUND: Non-modulating hypertensives are a subset of sodium-sensitive hypertensives characterized by a failure to modulate renal, vascular and adrenal glomerulosa responsivenesses to angiotensin II appropriately. OBJECTIVE: To investigate the plasma renin activity (PRA) and urinary kallikrein-like activity (Ku) under different sodium conditions in essential hypertensive patients and in the modulating and non-modulating subsets of hypertensives. Additionally, in these groups of patients, the effects on blood pressure of a sustained Na+ restriction were evaluated. METHODS: Fifteen normotensives (10 men, aged 29 +/- 5 years) and 54 untreated hypertensives (30 men, aged 34 +/- 7 years) were each administered subsequently three different diets containing 240, 140 and 50 mmol/day Na+, each diet for 10 days. At the end of each period, the PRA, Ku, 24 h urinary volume and urinary Na+ excretion were measured. Afterwards, the essential hypertensives were classified as 29 modulating essential hypertensives (MHT, 20 men, aged 32 +/- 7 years) and 25 non-modulating essential hypertensives (NMHT, 10 men, aged 36 +/- 8 years). Non-modulating ones were identified as individuals who failed to increase their effective renal plasma flow and to decrease their filtration fraction by at least 30% from baseline values, 10 days after changing from a low (10 mmol/day) to a high (260 mmol/day) Na+ intake. Blood pressure was measured with a Dinamap 8100 Critikon device. Both PRA and Ku were measured during normal Na+ intake by standard methods. Patients were administered a low-Na+ diet (10-50 mmol/day) for 12 months. RESULTS: In essential hypertensives, Ku was lower under the three Na+ diets than it was in normotensives (P < 0.01) whereas the PRA was higher in hypertensives only during the low Na+ intake (P < 0.01). The non-modulating patients showed significantly higher PRA levels (4.0 +/- 0.8 ng ml h, P < 0.05) than did modulating ones (2.6 +/- 1.0 ng ml h) or normotensives (2.3 +/- 1.0 ng ml h). Conversely, non-modulating hypertensives had lower Ku (4.1 +/- 1.0 IU/24 h, P < 0.025) than did modulating ones (6.2 +/- 1.0 IU/24 h) or normotensives (7.8 +/- 2.0 IU/24 h). Blood pressure was significantly reduced during low Na+ intake only in normotensives (month 6: 143 +/- 4/94 +/- 2 mmHg; month 12: 139 +/- 5/89 +/- 3 mmHg) compared with baseline values (169 +/- 4/102 +/- 6 mmHg, P < 0.025). CONCLUSIONS: It was shown that, in non-modulating hypertensives, in addition to an increased PRA, a reduced kallikrein-like activity coexists and seems to be associated with the impaired Na+ handling. Moreover, in these untreated patients the Na+ restriction was able to exert an antihypertensive effect even for long periods.

Adult↗
PubMed1996

Cardiorespiratory and renal responses to arterial chemoreceptor stimulation by hypoxia or almitrine in men.

1. The cardiorespiratory and renal responses to 3 h of normobaric whole-body hypoxic hypoxia (FiO2 = 0.12) as well as to arterial chemoreceptor stimulation by the oral administration of 100 mg almitrine bismesylate during normoxia were measured in 12 normotensive young men undergoing water diuresis. A third series of responses obtained under comparable conditions in the same subjects served as time controls. 2. No significant changes could be detected over time in the parameters measured in control experiments. The subjects reacted to both whole-body hypoxic hypoxia and to pharmacological chemoreceptor stimulation with significant increases in heart rate, tidal volume, minute ventilation and filtration-fraction. Overall renal vascular resistance rose significantly in hypoxia; increases in renal vascular resistance in almitrine experiments were not significant. 3. Renal fractional lithium excretion decreased significantly in response to whole-body hypoxic hypoxia and increased slightly in response to almitrine. Fractional urine and sodium excretion showed negligible changes. 4. The data indicate that, in humans, both almitrine and whole-body hypoxic hypoxia affect not only alveolar ventilation but also renal haemodynamics. 5. The renal electrolyte excretion pattern suggests that under certain circumstances (e.g. dilated renal vascular bed) acute, but well-tolerated, whole-body hypoxic hypoxia can simultaneously stimulate renal proximal tubular sodium reabsorption and inhibit distal tubular sodium reabsorption. The renal tubular responses also indicate that almitrine may influence renal tubular lithium reabsorption by, thus far, unknown mechanisms.

Adult↗
PubMed1996

Comparison of a spectrophotometric microdilution method with RPMI-2% glucose with the National Committee for Clinical Laboratory Standards reference macrodilution method M27-P for in vitro susceptibility testing of amphotericin B, flucytosine, and fluconazole against Candida albicans.

The National Committee for Clinical Laboratory Standards has proposed a reference broth macrodilution method for in vitro antifungal susceptibility testing of yeasts (the M27-P method). This method is cumbersome and time-consuming and includes MIC endpoint determination by visual and subjective inspection of growth inhibition after 48 h of incubation. An alternative microdilution procedure was compared with the M27-P method for determination of the amphotericin B, flucytosine, and fluconazole susceptibilities of 8 American Type Culture Collection strains (6 of them were quality control or reference strains) and 50 clinical isolates of candida albicans. This microdilution method uses as culture medium RPMI 1640 supplemented with 18 g of glucose per liter (RPMI-2% glucose). Preparation of drugs, basal medium, and inocula was done by following the recommendations of the National Committee for Clinical Laboratory Standards. The MIC endpoint was calculated objectively from the turbidimetric data read at 24 h. Increased growth of C. albicans in RPMI-2% glucose and its spectrophotometric reading allowed for the rapid (24 h) and objective calculation of MIC endpoints compared with previous microdilution methods with standard RPMI 1640. Nevertheless, good agreement was shown between the M27-P method and this microdilution test. The MICs obtained for the quality control or reference strains by the microdilution method were in the ranges published for those strains. For clinical isolates, the percentages of agreement were 100% for amphotericin B and fluconazole and 98.1% for flucytosine. These data suggest that this microdilution method may serve as a less subjective and more rapid alternative to the M27-P method for antifungal susceptibility testing of yeasts.

Amphotericin B↗
PubMed1996

NMDA-receptor-mediated synaptic currents in guinea pig laterodorsal tegmental neurons in vitro.

1. Whole cell voltage-clamp techniques were used to record glutamate-receptor-mediated synaptic currents from neurons of the laterodorsal tegmental nucleus (LDT). The principal cells of the LDT contain acetylcholine and nitric oxide synthase, and are believed to be involved in the control of sleep-waking behavior via widespread projections to the thalamus and brain stem. LDT cells were recorded from slices of mature guinea pig brain stem with patch pipette solutions containing cesium as the primary cation. 2. Application of N-methyl-D-aspartate (NMDA) elicited currents that were strongly voltage dependent with a mean reversal potential of +16.3 mV. Peak currents occurred near -15 mV, and a region of negative slope conductance was seen at more negative potentials. Application of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid evoked currents that exhibited a nearly linear current-voltage relation with a mean reversal potential of -3.4 mV. 3. Electrical stimulation of local afferents elicited dual-component excitatory postsynaptic currents (EPSCs) with decays that were well fitted by the sum of two exponentials. Mean decay time constants at -60 mV were 8.77 ms for the faster component and 129.4 ms for the slower component. The faster component displayed a linear current-voltage relation and was blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or 6,7-dinitroquinoxaline-2,3-dione, indicating that it was mediated by non-NMDA receptors, whereas the slower component displayed a voltage dependence similar to that for NMDA-evoked currents and was blocked by 2-amino-5-phosphonopentanoic acid (AP-5), indicating its mediation by NMDA receptors. 4. The fractional contribution of NMDA receptors to the EPSC was estimated from double-exponential curve fits to the decay phases. With this method, NMDA receptors were estimated on average to carry 10.1% of the total peak EPSC at -60 mV. Blockade of the non-NMDA-receptor-mediated component with CNQX revealed a residual EPSC whose amplitude was 14.4% of the control value, whereas AP-5 alone reduced the control EPSC peak by 16.1%, both values were comparable with those obtained from curve fit estimates. 5. Previous work has shown that the presence of 4-aminopyridine-sensitive, A-like transient current in LDT cells is correlated with the cholinergic phenotype. The majority of cells in this study exhibited A-like transient currents that were blocked by 4-amino-pyridine, suggesting that the majority of the data were obtained from the cholinergic and NOS-containing neurons of the LDT nucleus. 6. These experiments demonstrate the synaptic activation of functional NMDA and non-NMDA receptors in LDT neurons, and indicate that NMDA receptors contribute to fast excitatory transmission in these cells. The results suggest that afferents releasing excitatory amino acids may play an important role in controlling the state-dependent activity of LDT neurons.

Animals↗
PubMed1996

Cell density-dependent regulation of basic fibroblast growth factor expression in human renal cell carcinoma cells.

We investigated some of the mechanisms that regulate the expression of basic fibroblast growth factor (bFGF) in human renal cell carcinoma (HRCC). HRCC SN12PM6 cells were cultured as adherent monolayers. The expression of steady-state bFGF mRNA (measured by in situ hybridization and Northern blot) and protein (measured by immunohistochemistry and ELISA) correlated inversely with the culture density. Tumor cells harvested from dense cultures (low bFGF expression) and plated under sparse conditions expressed high levels of bFGF mRNA and protein prior to cell division, suggesting that bFGF may be a competence factor. Similar data were obtained with human vascular endothelial cells. The expression of bFGF was not regulated by spent culture medium, cell cycle, or rate of cell division but was down-regulated by contract inhibition. These data show that the expression of bFGF in HRCC is cell density dependent.

Carcinoma, Renal Cell↗
PubMed1996

Cardiorespiratory and renal responses to arterial chemoreceptor stimulation in early hypertension.

The peripheral arterial chemoreceptors (PAC) modify not only cardiorespiratory but also renal hemodynamic and excretory function. There is evidence that in hypertensive animals and humans the reflectoric actions of the PAC on ventilation and circulation differ from those of normotensive subjects. However, the influence of these receptors on kidney function of hypertensive subjects is poorly understood. Cardiorespiratory and renal responses to pharmacological stimulation of PAC by almitrine bismesylate during normoxia were measured in 16 normotensive (NT) and 13 age-matched borderline-hypertensive young men (BHT) undergoing water diuresis. Placebo experiments served as time controls in each subject. NT reacted to almitrine with significant rises in heart rate, minute ventilation, and filtration fraction. Renal vascular resistance tended to increase slightly. In BHT the drug caused a significant rise in heart rate and minute ventilation too, however, this reaction had a longer latency when compared to NT. In contrast to NT, filtration fraction, and renal vascular resistance decreased. Renal fractional sodium and lithium excretion did not show any clear response to almitrine in NT, but decreased in BHT. The results suggest that the weaker ventilatory response in BHT vs. NT might indicate a lower reactivity of their PAC to almitrine. The different reactions of the renal vascular bed to pharmacological chemoreceptor excitation in mild hypertensives might result from a different reactivity of the renal arterioles, whereas the enhanced proximal tubular sodium reabsorption could be due to an exaggerated increase in efferent renal nerve activity.

Adult↗
PubMed1996

Panel discussion: impact of guidelines on third-party payors and HMOs.

Utilization management (preauthorization) has given way to disease management, i.e., the management, by providers in cooperation with third-party payors, of patients and their disease states from beginning to end. Managed-care organizations are seeking guidelines-based cancer disease management programs that result in: lower, more predictable costs; authoritative quality assurance; measured outcomes; reduced preauthorization disputes; and improved management of cases in clinical trials. Guidelines also need to provide some consistency and consensus regarding the management of common clinical problems. Good guidelines help assist managed-care companies gather data, build a more solid utilization management foundation and support a clinically sound disease management program. Aetna's Institutes of Excellence (IOE) program seeks to address the issue of coverage for high-dose chemotherapy and bone marrow transplantation, but can serve as a useful model for the development of comprehensive cancer networks.

Clinical Trials as Topic↗
PubMed1995

Interferons alpha and beta down-regulate the expression of basic fibroblast growth factor in human carcinomas.

We investigated the influence of interferons alpha, beta, and gamma (IFN-alpha, -beta, and -gamma) on the production of basic fibroblast growth factor (bFGF) by human renal carcinoma cells. The human renal carcinoma cell metastatic line SN12PM6 was established in culture from a lung metastasis and SN12PM6-resistant cells were selected in vitro for resistance to the antiproliferative effects of IFN-alpha or IFN-beta. IFN-alpha and IFN-beta, but not IFN-gamma, down-regulated the expression of bFGF at the mRNA and protein levels by a mechanism independent of their antiproliferative effects. Down-regulation of bFGF required a long exposure (> 4 days) of cells to low concentrations (> 10 units/ml) of IFN-alpha or IFN-beta. The withdrawal of IFN-alpha or IFN-beta from the medium permitted SN12PM6-resistant cells to resume production of bFGF. The incubation of human bladder, prostate, colon, and breast carcinoma cells with noncytostatic concentrations of IFN-alpha or IFN-beta also produced down-regulation of bFGF production.

Base Sequence↗
PubMed1995

Identification and characterization of the G15D mutation found in a male patient with 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency: alteration of the putative NAD-binding domain of type II 3 beta-HSD.

We report the detection of a homozygous G to A mutation converting codon Gly15 into Asp15 in the type II 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta-HSD) gene in a male pseudo-hermaphrodite born from consanguineous parents and suffering from severe salt-losing 3 beta-HSD deficiency. To investigate further the potential involvement of residue 15 in the beta alpha beta dinucleotide-binding fold, we have studied the effect of substituting Gly15 for Ala15. We assessed the effect of the G15D and G15A missense mutations on enzymatic activity by analyzing mutant enzymes generated by site-directed mutagenesis of type II 3 beta-HSD cDNA after their transient expression in COS-1 cells. In intact transfected cells, after a 2-h incubation, the percentage of conversion of [3H]pregnenolone (PREG) into [3H]progesterone (PROG) was 35% and 50% for the G15A and native type II 3 beta-HSD enzymes, respectively, whereas no detectable activity was observed in cells expressing the G15D protein. This finding is in agreement with the severity of the disease in the homozygote G15D index case. On the other hand, in homogenates from cells transfected with the normal pCMV-type II 3 beta-HSD plasmid or with the mutated pCMV-G15D or pCMV-G15A plasmid, the Km values for PREG were 0.72 microM, 3.2 microM, and 3.4 microM, respectively, when incubated for 1 h in the presence of excess (1 mM) NAD+. Moreover, the expressed G15D and G15A proteins had decreased affinities for NAD+ with Km values of 113 microM and 148 microM, respectively, compared with 22 microM for normal type II 3 beta-HSD.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗
PubMed1995

Molecular basis of human 3 beta-hydroxysteroid dehydrogenase deficiency.

The enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) catalyses an essential step in the biosynthesis of all classes of steroid hormones. Classical 3 beta-HSD deficiency is responsible for CAHII, a severe form of congenital adrenal hyperplasia (CAH) that impairs steroidogenesis in both the adrenals and gonads. Newborns affected by 3 beta-HSD deficiency exhibit signs and symptoms of adrenal insufficiency of varying degrees associated with pseudohermaphroditism in males, whereas females exhibit normal sexual differentiation or mild virilization. Elevated ratios of 5-ene-to 4-ene-steroids appear as the best biological parameter for the diagnosis of 3 beta-HSD deficiency. The nonclassical form has been suggested to be related to an allelic variant of the classical form of 3 beta-HSD as described for steroid 21-hydroxylase deficiency. To elucidate the molecular basis of the classical form of 3 beta-HSD deficiency, we have analysed the structure of the highly homologous type I and II 3 beta-HSD genes in 12 male pseudohermaphrodite 3 beta-HSD deficient patients as well as in four female patients. The 14 different point mutations characterized were all detected in the type II 3 beta-HSD gene, which is the gene predominantly expressed in the adrenals and gonads, while no mutation was detected in the type I 3 beta-HSD gene predominantly expressed in the placenta and peripheral tissues. The finding of a normal type I 3 beta-HSD gene provides the explanation for the intact peripheral intracrine steroidogenesis in these patients and increased androgen manifestations at puberty. The influence of the detected mutations on enzymatic activity was assessed by in vitro expression analysis of mutant enzymes generated by site-directed mutagenesis in COS-1 cells. The mutant type II 3 beta-HSD enzymes carrying mutations detected in patients affected by the salt-losing form exhibit no detectable activity in intact transfected cells, whereas those with mutations found in nonsalt-loser index cases have some residual activity ranging from approximately 1-10% compared to the wild-type enzyme. Although in general, our findings provide a molecular explanation for the enzymatic heterogeneity ranging from the severe salt-losing form to the clinically inapparent salt-wasting form of the disease, we have observed that the mutant L108W or P186L enzymes found in a compound heterozygote male presenting the salt-wasting form of the disease, has some residual activity (approximately 1%) similar to that observed for the mutant N100S enzyme detected in a homozygous male patient suffering from a nonsalt-losing form of this disorder.(ABSTRACT TRUNCATED AT 400 WORDS)

3-Hydroxysteroid Dehydrogenases↗