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Biomedical subjects

N Gomez

Publications and source records attributed to N Gomez.

At least 19 recordsLinked to original sources
PubMed2004

PrP polymorphisms in Basque sheep breeds determined by PCR-restriction fragment length polymorphism and real-time PCR.

Two new PCR-based methods were developed to decode prion protein (PrP) gene polymorphisms at codons 136, 154 and 171: a PCR-restriction fragment length polymorphism (RFLP) analysis consisting of two PCR reactions followed by three enzymatic digestions, and a real-time PCR consisting of four reactions with seven fluorogenic probes. Both methods were used to study the distribution of PrP gene polymorphisms in a representative sample (1297 animals) of the populations of the two native breeds of sheep of the Spanish Basque Country, Latxa and Carranzana. Fourteen genotypes were found in the Latxa breed, in which ARQ/ARQ was the genotype most frequently observed (49.3 per cent), followed by ARR/ARQ (32.6 per cent) and ARQ/ARH (5.8 per cent). The genotype associated with the highest resistance to scrapie (ARR/ARR) was present in 5 per cent of the animals analysed. Similar results were observed in the Carranzana sheep.

Animals↗
PubMed2001

Patient and physician satisfaction in a clinical study of telemedicine in a hypertensive patient population.

We studied patient and physician satisfaction with telemedicine for the care of a hypertensive population. Once recruited, participants were seen both in person and via telemedicine (in random order) on the same day. After each meeting, patient and physician satisfaction surveys were completed. In the 12-month study, there were 107 pairs of visits. The physicians reported a small but significant increase in workload, mental effort, technical skills and visit duration for telemedicine when compared with face-to-face consultations. They noted that the telemedicine system worked well in the majority of cases and could reduce the need for future treatment. Patients reported slightly but significantly higher satisfaction scores for the following for in-person than for telemedicine meetings: technical quality, interpersonal care and time spent. Patients reported high satisfaction scores for both telemedicine and in-person visits.

Aged↗
PubMed2000

Helicopter emergency medical service in Canary Islands, Spain.

This is a report on our first 2 years' experience of operating a helicopter emergency medical service in the Canary Islands, Spain. The two advanced life-support helicopters are staffed full time by a physician and a nurse. For the transport protocol, inter-hospital transport patients (secondary missions) were classified into three groups: group A, minor illnesses or injuries; group B, modified or middle critical condition; and group C, critical condition. On-scene patients (primary missions) were also divided into critical and non-critical condition. Cardiovascular and respiratory stabilization were necessary before transport. One thousand and fifty-four patients were transported, 19% of whom were primary missions and 81% of whom were secondary missions. Thirty per cent of the first group were in critical condition. The distribution of secondary missions was group A 16%, group B 44% and group C 40%. In group C, 60% of patients were mechanically ventilated, 70% needed cardiovascular drug support and 84% needed stabilization before transport. Thirty-two per cent were trauma patients and 12% neonates. The overall mortality rate was 0.8%. The cost per mission was US$2300. In the interests of safety and rationalization of the use of resources, transport of non-critical patients should be reduced. The presence of a trained physician and nursing crew and stabilization before transport could be responsible for the low mortality rate.

Adolescent↗
PubMed2000

MMPI-2 profiles of Colombian, Mexican, and Venezuelan university students.

Performance of 82 Colombian, 87 Mexican, and 96 Venezuelan university students and adult community dwellers on Spanish translations of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) were compared. Findings suggest more comprehensive research is required on applications of the MMPI-2 in Latin America and greater consideration of the roles of culture and nationality.

Adolescent↗
PubMed1999

Both group IB and group IIA secreted phospholipases A2 are natural ligands of the mouse 180-kDa M-type receptor.

Snake venom and mammalian secreted phospholipases A2 (sPLA2s) have been associated with toxic (neurotoxicity, myotoxicity, etc.), pathological (inflammation, cancer, etc.), and physiological (proliferation, contraction, secretion, etc.) processes. Specific membrane receptors (M and N types) for sPLA2s have been initially identified with snake venom sPLA2s as ligands, and the M-type 180-kDa receptor was cloned from different animal species. This paper addresses the problem of the endogenous ligands of the M-type receptor. Recombinant group IB and group IIA sPLA2s from human and mouse species have been prepared and analyzed for their binding properties to M-type receptors from different animal species. Both mouse group IB and group IIA sPLA2s are high affinity ligands (in the 1-10 nM range) for the mouse M-type receptor. These two sPLA2s are expressed in the mouse tissues where the M-type receptor is also expressed, making it likely that both types of sPLA2s are physiological ligands of the mouse M-type receptor. This conclusion does not hold for human group IB and IIA sPLA2s and the cloned human M-type receptor. The two mouse sPLA2s have relatively high affinities for the mouse M-type receptor, but they can have much lower affinities for receptors from other animal species, indicating that species specificity exists for sPLA2 binding to M-type receptors. Caution should thus be exerted in avoiding mixing sPLA2s, cells, or tissues from different animal species in studies of the biological roles of mammalian sPLA2s associated with an action through their membrane receptors.

3T3 Cells↗
PubMed1998

The yeast halotolerance determinant Hal3p is an inhibitory subunit of the Ppz1p Ser/Thr protein phosphatase.

Components of cellular stress responses can be identified by correlating changes in stress tolerance with gain or loss of function of defined genes. Previous work has shown that yeast cells deficient in Ppz1 protein phosphatase or overexpressing Hal3p, a novel regulatory protein of unknown function, exhibit increased resistance to sodium and lithium, whereas cells lacking Hal3p display increased sensitivity. These effects are largely a result of changes in expression of ENA1, encoding the major cation extrusion pump of yeast cells. Disruption or overexpression of HAL3 (also known as SIS2) has no effect on salt tolerance in the absence of PPZ1, suggesting that Hal3p might function upstream of Ppz1p in a novel signal transduction pathway. Hal3p is recovered from crude yeast homogenates by using immobilized, bacterially expressed Ppz1p fused to glutathione S-transferase, and it also copurifies with affinity-purified glutathione S-transferase-Ppz1p from yeast extracts. In both cases, the interaction is stronger when only the carboxyl-terminal catalytic phosphatase domain of Ppz1p is expressed. In vitro experiments reveal that the protein phosphatase activity of Ppz1p is inhibited by Hal3p. Overexpression of Hal3p suppresses the reduced growth rate because of the overexpression of Ppz1p and aggravates the lytic phenotype of a slt2/mpk1 mitogen-activated protein kinase mutant (thus mimicking the deletion of PPZ1). Therefore, Hal3p might modulate diverse physiological functions of the Ppz1 phosphatase, such as salt stress tolerance and cell cycle progression, by acting as a inhibitory subunit.

Binding Sites↗
PubMed1997

Evidence for survival and metabolic activity of encapsulated xenogeneic hepatocytes transplanted without immunosuppression in Gunn rats.

BACKGROUND: Hepatocyte transplantation could be an alternative to whole organ transplantation to correct enzymatic disorders. To this end, it would be of major importance to use xenogeneic cells without immunosuppression. The aim of this study was to investigate the survival and metabolic activity of encapsulated xenogeneic hepatocytes in the absence of immunosuppression. For this purpose, we used Gunn rats genetically incapable of bilirubin conjugation. METHODS: Xenogeneic (from guinea pigs) and allogeneic (from Lewis rats) hepatocytes (2x10(7)) were isolated, macroencapsulated in hydrogel hollow fibers made with an acrylonitrile-sodium methallyl-sulfonate copolymer, and transplanted into the peritoneum of Gunn rats without any immunosuppression. Plasma bilirubin levels were evaluated weekly. Bilirubin conjugates in bile and cell morphology were studied after 5 and 12 weeks, respectively. RESULTS: In Gunn rats transplanted with xenogeneic hepatocytes, a significant decrease in the serum bilirubin level was observed between 3 and 9 weeks after transplantation when compared with controls transplanted with empty hollow fibers: it fell to 62% of the initial level at weeks 5-7 (P < 0.01). A comparable result was observed in Gunn rats transplanted with encapsulated allogeneic cells. Bilirubin conjugates were observed in bile samples of rats transplanted with encapsulated hepatocytes. After explantation, hollow fibers appeared intact with minimal fibrosis. Cell viability and hepatocyte morphology were preserved. CONCLUSIONS: These results indicate that macroencapsulated xenogeneic hepatocytes can survive and remain functional for more than 2 months when transplanted in vivo in the absence of any immunosuppression.

Acrylic Resins↗
PubMed1997

Androgen regulation of lung lipids in the male rat.

The aim of this study was to determine whether or not testosterone regulates the lipid concentration in rat lung tissue. Rats were either sham-operated controls, castrated, or castrated and injected with testosterone. Twenty-one days after castration, we observed in relation to the control: (i) Total lipids, phospholipids, and total cholesterol increased, while triglycerides decreased in whole lung. (ii) Phospholipid concentration increased in microsomes, lamellar bodies, and alveolar macrophages, but it decreased in extracellular surfactant. (iii) On a percentage basis, the concentration of phosphatidylcholine increased in microsomes, lamellar bodies, and alveolar macrophages, and it decreased in extracellular surfactant. (iv) Protein concentration decreased in extracellular surfactant and increased in microsomes, lamellar bodies, and alveolar macrophages. (v) The incorporation of [14C]glycerol into phospholipids of lung slices increased. (vi) The activity of CTP:phosphocholine cytidylytransferase bound to the microsomal fraction increased without any change in the activity of the soluble form of the enzyme in the lung. The results obtained when testosterone was administered to castrated rats were similar to those obtained in the control in all cases. These results suggest that the lipid concentration in the lung is regulated at least partly directly or indirectly by androgens.

Animals↗
PubMed1995

Inactivation of p42 MAP kinase by protein phosphatase 2A and a protein tyrosine phosphatase, but not CL100, in various cell lines.

BACKGROUND: Mitogen-activated protein (MAP) kinase is central to a signal transduction pathway that triggers cell proliferation or differentiation. Activation of the p42mapk isoform requires its phosphorylation at two residues, Thr 183 and Tyr 185, and this phosphorylation is catalysed by MAP kinase kinase (MAPKK). Relatively little is known, however, about the enzymes that dephosphorylate these residues, thereby inactivating the pathway. Recently, the CL100 phosphatase has been shown to inactivate p42mapk in vitro by dephosphorylating Thr 183 and Tyr 185 at similar rates. CL100, the product of an immediate early gene, is synthesized within one hour of stimulating cells with growth factors or exposure to oxidative stress or heat shock. Incubation of NIH 3T3 fibroblasts with cycloheximide prevents both synthesis of CL100 and inactivation of p42mapk after stimulation with serum. RESULTS: Depleting cells of CL100 and preventing its induction using cycloheximide stopped the inactivation of p42mapk in Swiss 3T3 fibroblasts following stimulation with epidermal growth factor (EGF), but had no effect on the rapid inactivation of p42mapk in response to EGF in adipose (3T3-L1) or chromaffin (PC12) cells or in response to platelet-derived growth factor (PDGF) in endothelial (PAE) cells. Moreover, maximal induction of CL100 mRNA and a CL100-like activity did not trigger inactivation of p42mapk, which was sustained at a high level after stimulation of PC12 cells with nerve growth factor, PAE cells with serum, or Swiss 3T3 cells with PDGF. Dephosphorylation of Tyr 185 but not Thr 183 of p42mapk was suppressed by vanadate in EGF-stimulated PC12 cells; dephosphorylation of Thr 183, by contrast, was elicited by a vanadate-insensitive activity. Protein phosphatase-2A was the only vanadate-insensitive phosphatase acting on Thr 183 of p42mapk or on MAPKK to be detected in PC12 cell extracts. Phosphorylation of Thr 183 also inhibited the dephosphorylation of Tyr 185 in vitro by the major vanadate-sensitive Tyr 185-specific phosphatase, explaining why dephosphorylation of Thr 183 is rate-limiting for p42mapk inactivation in PC12 cells after stimulation with EGF. CONCLUSIONS: The rapid inactivation of p42mapk initiated five minutes after stimulation of endothelial, adipose and chromaffin cells with growth factor is not catalysed by CL100, but rather by protein phosphatase 2A and by a protein tyrosine phosphatase distinct from CL100. Induction of CL100 is not accompanied by the inactivation of p42mapk in a number of situations.

3T3 Cells↗
PubMed1995

Microalbuminuria is associated with limited joint mobility in type I diabetes mellitus.

OBJECTIVE: To determine whether limited joint mobility (LJM) is associated with microalbuminuria in type I diabetes mellitus. METHODS: Joint mobility was measured in a control group of 63 healthy subjects and in 63 type I diabetic patients, older than 18 years (mean 31.7 years, range 18-57), recruited from the outpatient clinic of the Endocrine Unit. Patients with established diabetic nephropathy (proteinuria or increased creatinine) were excluded. Joint mobility was assessed qualitatively with the prayer manoeuvre and quantitatively by measuring the angles of maximal flexion and extension of the fifth and third metacarpophalangeal (MCP) joints and wrist. Diabetic retinopathy was assessed by direct ophthalmoscopy. Urinary albumin excretion (UAE) was determined in at least two 24 hour urine samples. RESULTS: Joint mobility was limited in diabetic patients compared with control subjects. Diabetic patients with LJM had longer duration of diabetes (12.1 (SD 6.4) years compared with 6.9 (5.7) years; p < 0.001). Joint mobility was limited in patients with retinopathy: prayer manoeuvre was positive in 96.4% of patients with retinopathy, but in only 40.0% of patients with no retinopathy (p < 0.001); mobility of MCP joints and wrist was limited in diabetic patients with retinopathy even when the longer duration of their diabetes was taken into consideration. Microalbuminuria, present in 11 patients (17.5%), was associated with LJM: prayer manoeuvre was positive in 90.9% of patients with microalbuminuria, but in only 57.4% of patients with normal UAE (p < 0.05). Maximal flexion of MCP joints was reduced in patients with microalbuminuria. Microalbuminuria, but not LJM, was associated with risk factors of cardiovascular disease. CONCLUSION: LJM is associated with microalbuminuria and retinopathy in type I diabetes. The association is independent of age and duration of diabetes.

Adolescent↗
PubMed1994

The threonine residues in MAP kinase kinase 1 phosphorylated by MAP kinase in vitro are also phosphorylated in nerve growth factor-stimulated rat phaeochromocytoma (PC12) cells.

The residues on MAP kinase kinase-1 (MAPKK1) phosphorylated by MAP kinase in vitro have been identified as Thr-291 and Thr-385. Both threonines are phosphorylated in PC12 cells and the 32P-labelling of each residue increases after stimulation with nerve growth factor (NGF). The results establish that MAPKK1 is a physiological substrate for MAP kinase. The two active forms of MAPKK that are resolved by Mono Q chromatography of PC12 cell extracts are both phosphorylated at Thr-291 and Thr-385, demonstrating that neither species is the MAPKK2 isoform which lacks Thr-291.

Amino Acid Sequence↗
PubMed1993

The protein kinase mos activates MAP kinase kinase in vitro and stimulates the MAP kinase pathway in mammalian somatic cells in vivo.

The mos protooncogene encodes a serine/threonine protein kinase that is only expressed at significant levels in germ cells. Recombinant malE-mos protein (Xenopus mos protooncogene fused in frame to the maltose binding protein of E. coli) activates MAP kinase in cell-free extracts prepared from Xenopus oocytes and eggs. Here we show that malE-mos immunoprecipitates from Xenopus extracts phosphorylate and activate MAP kinase kinase in vitro, indicating that mos can function as a MAP kinase kinase kinase. Moreover, ectopic expression of mos in mammalian somatic cells, that lack any endogenous mos protein, triggers the activation of MAP kinase in vivo. These results identify the mos protooncogene as a direct activator of the MAP kinase pathway, with the potential to activate this kinase cascade even in cells where normally there is no expression of mos.

3T3 Cells↗
PubMed1993

[Serum testosterone: a possible marker for colorectal cancer].

A reduction of circulating testosterone has been reported in lung, stomach and pancreatic carcinoma. In order to evaluate the concentration of this hormone in patients with colorectal cancer, we studied 58 men with histologically confirmed disease. Seric testosterone, estradiol and carcinoembryogenic antigen were simultaneously measured in 24 patients under pre-surgical evaluation (group I) and in 34 patients after surgical resection (group II). The results were compared with a control group carrying benign gastrointestinal pathologies. According to the Kruskal-Wallis test, the testosterone level in cancer groups was significantly lower than in the control group (p < 0.0001). We have also observed a statistical significance between subgroups I and II compared to the control group (p < 0.001), while no conspicuous differences were perceived in estradiol concentrations between benign and cancer groups. Decreased serum levels of testosterone were found in 69% of patients with colon or rectal carcinoma and 56.9% of them had raised levels of carcinoembryonic antigen. The combined determination of both biomarkers increase to 86.2% the sensitivity of tumor screening compared with a single detection. Our results suggest that the combination of testosterone and carcinoembryonic antigen enhances the efficiency of tumor screening. We conclude that the evaluation of circulating testosterone could be a new and more sensitive assay for diagnosis and follow-up of colorectal carcinoma in males, specially in patients with normal levels of carcinoembryonic antigen.

Adult↗
PubMed1992

Identification of a MAP kinase kinase kinase in phaeochromocytoma (PC12) cells.

A MAP kinase kinase kinase (MAPKKK) was identified in phaeochromocytoma (PC12) cells which reactivated homogeneous MAP kinase kinase (MAPKK) from rabbit skeletal muscle that had been inactivated by incubation with protein phosphatase 2A. Reactivation was accompanied by stoichiometric phosphorylation of MAPKK on a serine residue(s). Following stimulation of PC12 cells with nerve growth factor and chromatography of the extracts on Mono Q, MAP kinase and MAPKK were detected as active phosphorylated enzymes, whereas MAPKKK was inactive and only activated after prolonged storage at 4 degrees C. The results suggest that the activation of MAPKKK by growth factors is likely to occur by a non-covalent mechanism.

Animals↗
PubMed1992

Sustained activation of the mitogen-activated protein (MAP) kinase cascade may be required for differentiation of PC12 cells. Comparison of the effects of nerve growth factor and epidermal growth factor.

Stimulation of PC12 cells with nerve growth factor (NGF) increased mitogen-activated protein kinase kinase (MAPKK) activity > 20-fold after 5 min to a level that was largely sustained for at least 90 min. MAPKK activity was stimulated to a similar level by epidermal growth factor (EGF), but peaked at 2 min, declining thereafter and returning to basal levels after 60-90 min. Activation of MAPKK by either growth factor occurred prior to the activation of MAP kinase, consistent with MAPKK being the physiological activator of MAP kinase. The results demonstrate that the transient activation of MAPKK by EGF and its sustained activation by NGF underlies the transient and sustained activation of MAP kinase induced by EGF and NGF respectively. NGF or EGF induced the same two forms of MAPKK that were resolved on a Mono Q column. The Peak-1 MAPKK was activated initially and partially converted into the more acidic peak-2 MAPKK after prolonged growth-factor stimulation. The Peak-2 MAPKK was 20-fold more sensitive to inactivation by the catalytic subunit of protein phosphatase 2A. Stimulation with NGF caused a striking translocation of MAP kinase from the cytosol to the nucleus after 30 min, but not nuclear translocation of MAP kinase occurred after stimulation with EGF. The results suggest that sustained activation of the MAP kinase cascade may be required for MAP kinase to enter the nucleus, where it may initiate the gene transcription events required for neuronal differentiation of PC12 cells.

Animals↗