PubMed Health⌕ Search

Biomedical subjects

C Jimenez

Publications and source records attributed to C Jimenez.

At least 37 records · Page 2Linked to original sources
PubMed1999

Recipient factors as determinants of mortality after adult liver transplantation.

The factors that can influence the outcome of orthotopic liver transplantation (OLT) are numerous. The purpose of this study was to determine the effects of recipient preoperative factors on patient mortality. Between April 1986 and April 1998 a total of 600 OLTs were performed in our institution. We retrospectively reviewed our first 203 consecutive primary adult OLTs with at least 4 years of follow-up. A case-control comparison was performed between survivors and nonsurvivors, and differences in recipient variables were studied for their correlation with patient mortality. A logistic regression analysis was also performed. Mortality was significantly increased among those with fulminant hepatic failure (FHF) (66.6%, p = 0.003), primary cancer (63.1%, p = 0.018), females (46.1%, p = 0. 043), encephalopathy grade IV (72.7%, p = 0.012), recipients under respiratory support (69.2%, p = 0.031), and ABO-incompatible transplants (80%, p = 0.05). FHF, primary cancer, and female gender were the only variables that had a significant association with mortality in the logistic regression analysis. A higher incidence of prolonged respiratory support, bacterial and fungal infections, pneumonia, and chronic rejection contributed to the lower outcome observed in females. These results stress the need for continuous evaluation of the selection criteria of candidates for OLT suffering from primary cancer and FHF. The impact of recipient gender on mortality warrants further analysis but suggests that in the future more attention must be paid to the influence of this factor on the final outcome of OLT.

Adult↗
PubMed1999

Effects of acute hypobaric hypoxia on the appearance of ingested deuterium from a deuterium oxide-labelled carbohydrate beverage in body fluids of humans during prolonged cycling exercise.

To determine whether or not acute hypobaric hypoxia alters the rate of water absorption from a carbohydrate beverage ingested during exercise, six men cycled for 80 min on three randomly assigned different occasions. In one trial, exercise was performed in hypoxia (barometric pressure, P(B) = 594 hPa, altitude 4,400 m) at an exercise intensity selected to elicit 75% of the individual's maximal oxygen uptake (VO2max) previously determined in such conditions. In the two other experiments, the subjects cycled in normoxia (P(B) = 992 hPa) at the same absolute and the same relative intensities as in hypoxia, which corresponded to 55% and 75%, respectively, of their VO2max determined in normoxia. The subjects consumed 400 ml of a 12.5% glucose beverage just prior to exercise, and 250 ml of the same drink at 20, 40 and 60 min from the beginning of exercise. The first drink contained 20 ml of deuterium oxide to serve as a tracer for the entry of water into body fluids. The heart rate (HR) during exercise was higher in hypoxia than in normoxia at the same absolute exercise intensity, whereas it was similar to HR measured in normoxia at the same relative exercise intensity. Both in normoxia and hypoxia, plasma noradrenaline concentrations were related to the relative exercise intensity up to 40 min of exercise. Beyond that duration, when exercise was performed at the highest absolute power in normoxia, the noradrenaline response was higher than in hypoxia at the same relative exercise intensity. No significant differences were observed among experimental conditions, either in temporal profiles of plasma D accumulation or in elimination of water ingested in sweat. Conversely, elimination in urine of the water ingested appeared to be related to the severity of exercise, either high absolute power or the same relative power combined with hypoxia. We concluded that water absorption into blood after drinking a 12.5% glucose beverage is not altered during cycling exercise in acute hypobaric hypoxia. It is suggested that the elimination of water ingested in sweat and urine may be dependent on local circulatory adjustments during exercise.

Absorption↗
PubMed1999

Plasma volume changes during and after acute variations of body hydration level in humans.

This study examined plasma volume changes (deltaPV) in humans during periods with or without changes in body hydration: exercise-induced dehydration, heat-induced dehydration and glycerol hyperhydration. Repeated measurements of plasma volume were made after two injections of Evans blue. Results were compared to deltaPV calculated from haematocrit (Hct) and blood haemoglobin concentration ([Hb]). Eight well-trained men completed four trials in randomized order: euhydration (control test C), 2.8% dehydration of body mass by passive controlled hyperthermia (D) and by treadmill exercise (60% of their maximal oxygen uptake, VO2max) (E), and hyperhydration (H) by glycerol ingestion. The Hct, [Hb], plasma protein concentrations and plasma osmolality were measured before, during and after the changes in body hydration. Different Hct and [Hb] reference values were obtained to allow for posture-induced variations between and during trials. The deltaPV values calculated after two Evans blue injections were in good agreement with deltaPV calculated from Hct and [Hb]. Compared to the control test, mean plasma volume declined markedly during heat-induced dehydration [-11.4 (SEM 1.7)%] and slightly during exercise-induced dehydration [-4.2 (SEM 0.9)%] (P < 0.001 compared to D), although hyperosmolality was similar in these two trials. Conversely, glycerol hyperhydration induced an increase in plasma volume [+7.5 (SEM 1.0)%]. These results would indicate that, for a given level of dehydration, plasma volume is dramatically decreased during and after heat exposure, while it is better maintained during and after exercise.

Adult↗
PubMed1999

MRI diagnosis of gliomatosis cerebri.

Until recently the diagnosis of gliomatosis cerebri has been made on postmortem examination. This article reviews the use of serial magnetic resonance imaging studies to suggest premorbid diagnosis of this condition. The following is a case report of a 14-year-old female who had a subtotal cortical resection of tumor and several years later developed a progressive dementia. At postmortem examination the diagnosis of gliomatosis cerebri was made. Diffuse progressive white matter changes involving both hemispheres and brainstem, with increased thickness of the corpus callosum and without changes in cortical markings on T2-weighted magnetic resonance images, in this patient were highly suggestive of the diagnosis of gliomatosis cerebri.

Adolescent↗
PubMed1999

Absolute structures of new briarane diterpenoids from junceella fragilis

Four new diterpenoids with the briarane skeleton, (-)-4-deacetyljunceellolide D (2), (+)-11alpha, 20alpha-epoxyjunceellolide D (3), (-)-11alpha, 20alpha-epoxy-4-deacetyljunceellolide D (4), and (-)-11alpha, 20alpha-epoxy-4-deacetoxyjunceellolide D (5), (+)-junceellolide A (6) [the antipodal derivative of the known (-)-junceellolide A], along with three known briaranes, (-)-junceellolide D (1), (-)-junceellin (7), and (-)-praelolide (8), were isolated from the Indonesian gorgonian Junceella fragilis. The structures of the new compounds were established on the basis of extensive NMR studies and by comparison with the spectral data from other briarane compounds. The absolute configurations for four of the compounds were determined by the modified Mosher method and by unambiguous chemical interconversions.

Journal Article↗
PubMed1999

Up71 and up140, two novel transcripts of utrophin that are homologues of short forms of dystrophin.

Utrophin is a large protein which accumulates at the neuromuscular synapse and myotendinous junctions in adult skeletal muscle, and is widely expressed in several non-skeletal muscle tissues. Evidence from a variety of sources suggests that a successful strategy for treatment of Duchenne muscular dystrophy patients will be to increase expression of utrophin in muscle. There is still much to be learnt about utrophin gene regulation, in particular regarding alternative isoforms, their promoters and role in muscle and non-muscle tissues. Using 5"-RACE we have identified two novel transcripts of utrophin, Up71 and Up140, with unique first exons and promoters located in intron 62 and intron 44, respectively. These transcripts appear to be structural homologues of the short dystrophin transcripts, Dp140 and Dp71, emphasizing the high degree of structural conservation between the utrophin and dystrophin genes. RT-PCR shows that Up71 and Up140 are widely expressed in both human and mouse tissues, including skeletal muscle. We present evidence for transcript-specific differential mRNA splicing of exon 71, in both Up71 and Up140, similar to that described for dystrophin. No evidence for splicing of exon 78 of utrophin was found. This is in contrast to dystrophin and may reflect a subtle functional difference in patterns of phosphorylation between the two proteins.

Amino Acid Sequence↗
PubMed1999

Screening for cystic fibrosis transmembrane conductance regulator gene mutations in men included in an intracytoplasmic sperm injection programme.

The present study was undertaken to evaluate the frequency and nature of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in infertile patients undergoing intracytoplasmic sperm injection. A total of 90 patients were screened for a panel of 10 mutations in the CFTR gene frequently involved in congenital absence of the vas deferens (CAVD); the patients included 14 with azoospermia and CAVD, 39 patients with azoospermia without CAVD (n = 39) and 37 patients with severe oligozoospermia. The length of the polymorphic polypyrimidine tract (allele 5T, 7T and 9T) in the intron 8/exon 9 splice-acceptor site was also determined. In 10 out of 14 patients with CAVD, CFTR mutations were found; nine patients had one DeltaISOdiaDeltaF508 mutation and one patient had two CFTR mutations (N1303K/R117H). Allele 5T was present in eight of these patients. In six patients, 5T was the non-DeltaISOdiaDeltaF508 allele and in two patients there was no known CFTR mutation. None of the CFTR mutations were observed in patients with azoospermia without CAVD or with severe oligozoospermia and the frequency of allele 5T was 3.6% (three out of 78 alleles) and 1.35% (one out of 74 alleles) respectively. Our observation suggests that the CFTR gene is not involved in either spermatogenesis or in the pathology of the genital tract, except for CAVD.

Adult↗
PubMed1999

Recurrent abrupt occlusion after transluminal angioplasty for basilar artery stenosis: case report.

OBJECTIVE AND IMPORTANCE: Angioplasty for basilar artery stenosis is often complicated by recurrent abrupt vessel closure. The clinical results can be catastrophic. In this case report, we assess the effects of intra-arterial papaverine (American Regent Laboratories Inc., Shirley, NJ) on rebound occlusion. CLINICAL PRESENTATION: The patient presented with crescendo transient ischemic attacks from atherosclerotic narrowing of the midbasilar artery despite maximal medical treatment. INTERVENTION: Angioplasty of the midbasilar artery was performed with serial balloon inflations. The patient was treated successfully with intra-arterial papaverine and achieved a nearly full recovery, with only mild dysarthria, by the time of the 7-month follow-up examination. CONCLUSION: Using intra-arterial papaverine, we were able to reverse the effects of this potentially life-threatening complication of basilar artery angioplasty.

Angioplasty, Balloon↗
PubMed1998

A synthetic human Agouti-related protein-(83-132)-NH2 fragment is a potent inhibitor of melanocortin receptor function.

Chemical synthesis of Agouti proteins - Agouti and Agouti-related proteins - is complicated by their large size and by multiple cysteine residues located in the carboxyl terminal regions. Three human Agouti-related protein (AGRP) fragments, two of which correspond to a proposed endoprotease cleavage site between amino acids 82 and 83, were synthesized and tested for anti-melanotropic activity using Xenopus laevis dermal melanophores. Amino-terminal fragments AGRP(25-51) and (54-82) were devoid of significant antagonist activity, whereas the amidated carboxyl-terminal AGRP fragment (83-132)-NH2 was potently active with an inhibitory equilibrium dissociation constant (Ki) of 0.7 nM. The ability to synthesize functionally active AGRP should help unravel its role in the central nervous system and its unusual properties with respect to interaction with the melanocortin family of G-protein coupled receptors.

Agouti Signaling Protein↗
PubMed1998

Identification and characterization of a new oncogene derived from the regulatory subunit of phosphoinositide 3-kinase.

p85/p110 phosphoinositide 3-kinase (PI3K) is a heterodimer composed of a p85-regulatory and a p110-catalytic subunit, which is involved in a variety of cellular responses including cytoskeletal organization, cell survival and proliferation. We describe here the cloning and characterization of p65-PI3K, a mutant of the regulatory subunit of PI3K, which includes the initial 571 residues of the wild type p85alpha-protein linked to a region conserved in the eph tyrosine kinase receptor family. We demonstrate that this mutation, obtained from a transformed cell, unlike previously engineered mutations of the regulatory subunit, induces the constitutive activation of PI3K and contributes to cellular transformation. This report links the PI3K enzyme to mammalian tumor development for the first time.

3T3 Cells↗
PubMed1998

Influence of the oxygen uptake slow component on the aerobic energy cost of high-intensity submaximal treadmill running in humans.

During high-intensity running, the oxygen uptake (VO2) kinetics is characterised by a slow component which delays the attainment of the steady-state beyond the 3rd min of exercise. To assess if the aerobic energy cost of running measured at the 3rd min (C3) adequately reflects the variability of the true aerobic energy cost measured during the steady-state (Css), 13 highly-trained runners completed sessions of square-wave running at intensities above 80% maximal oxygen uptake (VO2max) on a level treadmill. To evaluate the time at which the steady-state VO2 was attained (tss), the VO2 responses were described using a general double-exponential equation and tss was defined as the time at which VO2 was less than 1% below the asymptotic value given by the model. All the subjects achieved a steady state for intensities equal to or greater than 92% VO2max, and 8 out of 13 achieved it at 99% VO2max. In all cases, tss was less than 13 min. For intensities greater than 85% VO2max, Css was significantly higher than C3 and was positively related to %VO2 max (r=0.44; P < 0.001) while C3 remained constant. The C3 only explained moderately the variability of Css (0.39 < r2 < 0.72, depending on the velocity or the (relative intensity at which the relationship was calculated). Moreover, the excess aerobic energy cost of running the (difference between Css and C3) was well predicted by age (0.90 < r2 < 0.93). Therefore, when the aerobic profile of runners is evaluated, it is recommended that their running efficiencies at velocities which reflect their race intensities should be determined, with VO2 data being measured at the true steady-state.

Adult↗
PubMed1998

Bone marrow metastasis in astrocytic gliomata.

With the increasing survival time of many pediatric patients with malignancies, unexpected symptoms or signs require diligent search for rare complications or second cancers related to the disease or treatment. We recently encountered a patient with extensive glioblastoma multiforme who developed pancytopenia six months after completion of treatment with craniospinal radiation and chemotherapy with etoposide and cyclophosphamide. Bone marrow aspirate and biopsy confirmed bone marrow metastasis from the brain tumor. He showed good partial remission with chemotherapy with carmustine and cis-platinum as demonstrated by serial bone marrow aspirate for cytology and cytogenetics and enjoyed good quality of life for eight months. 14 other patients with astrocytic glioma, two of whom are children, are reported in the literature to have diffuse bone marrow metastasis. Therefore, in patients with malignant astrocytic tumor, bone marrow metastasis, though not common, should be considered when bone pain or cytopenias occur, especially when prolonged.

Adolescent↗
PubMed1998

Essential monoclonal gammopathy with an IgM paraprotein that is a cryoglobulin with cold agglutinin and EDTA-dependent platelet antibody properties.

A patient with apparent anaemia and thrombocytopenia caused by a monoclonal paraprotein is described. The patient's serum contained a monoclonal IgM kappa, a cryoglobulin and a cold agglutinin. The cryoglobulin, similar to the serum paraprotein, was a monoclonal IgM kappa. Serum was studied to determine the relationship of the cryoglobulin with the cold agglutinin. The cryoglobulin and cold agglutinin were found to be the same paraprotein. Moreover, with absorption and elution techniques the reactivity of the autoantibody with both erythrocytes and platelets was demonstrated. Reports of cryoprecipitable cold agglutinins are rare and therefore this case is exceptional given that the IgM kappa paraprotein was found to be a cold agglutinin which was also reactive with platelets.

Aged↗
PubMed1997

Perianal fetal rhabdomyoma: case report.

A 4-week-old female was referred with a firm, enlarging perianal mass present since birth. At surgery, the lesion appeared to be arising from the subcutaneous external sphincter. Local excision was successful with preservation of the external sphincter. Histologic examination showed a mixture of undifferentiated spindle cells as well as immature and maturing myofibers consistent with a fetal rhabdomyoma. This report represents the second case of a fetal rhabdomyoma arising in the perianal location. All pediatric cases of fetal rhabdomyoma in the literature are reviewed.

Anal Canal↗
PubMed1997

Effects of different carbohydrate-electrolyte beverages on the appearance of ingested deuterium in body fluids during moderate exercise by humans in the heat.

To determine whether different forms of glucose (free and polymer) associated with sodium chloride influence the rate of water absorption during exercise in the heat, six men took part in five trials. Each trial included a passive heating session which resulted in a 2% loss of body mass, followed by 1h of treadmill exercise (at 50% of maximal oxygen uptake) in warm conditions (dry bulb temperature 35 degrees C, relative humidity 20%-30%). Immediately before exercise, the subjects were given either no fluid or a volume equal to 50% of the fluid previously lost (about 650 ml), chosen from among four D2O-labelled beverages: mineral water, a 6% glucose-electrolyte solution (GS), a 6% maltodextrin solution and a 6% maltodextrin-electrolyte solution. No significant differences were observed among these various beverages so far as temporal accumulation of deuterium in plasma, sweat and urine was concerned. During GS, the plasma volume was completely restored and the drifts of heart rate and rectal temperature were less marked than during other trials. These results would suggest that rehydration with GS was more efficient, probably because of an internal redistribution of water. The proportion of ingested water was twice as high in sweat as it was in urine. These findings may reflect the essential part played by circulatory adjustments in the transfer of plasma water into sweat and urine.

Adult↗
PubMed1997

Effects of hydration state on hormonal and renal responses during moderate exercise in the heat.

The effects of hydromineral hormones and catecholamines on renal concentrating ability at different hydration states were examined in five male volunteers while they performed three trials. Each of these trials comprised a 60-min exercise bout on a treadmill (at 50% of maximal oxygen uptake) in a warm environment (dry bulb temperature, 35 degrees C; relative humidity, 20-30%). In one session, subjects were euhydrated before exercise (C). In the two other sessions, after thermal dehydration (loss of 3% body mass) which markedly reduced plasma volume (PV) and increased plasma osmolality (osm[pl]), the subjects exercised either not rehydrated (Dh) or rehydrated (Rh) by drinking 600 ml of mineral water before and 40 min after the onset of exercise. During exercise in the Dh compared to C state, plasma renin, aldosterone, arginine vasopressin (AVP), noradrenaline and adrenaline concentrations were increased (P < 0.05). A reduction in creatinine clearance and urine flow was also observed (P < 0.05) together with a decrease in urine osmolality, osmolar clearance and sodium excretion, while free water clearance increased (P < 0.05). However, compared to Dh, Rh partially restored PV and osm(pl) and induced a marked reduction in the time courses of both the plasma AVP and catecholamine responses (P < 0.05). Values for renal water and electrolyte excretion were intermediate between those of Dh and C. Plasma atrial natriuretic peptide presented similar changes whatever the hydration state. These results demonstrate that during moderate exercise in the heat, renal concentrating ability is paradoxically reduced by prior dehydration in spite of high plasma AVP levels, and might be the result of marked activation of the sympatho-adrenal system. Rehydration, by reducing this activation, could partially restore the renal concentrating ability despite the lowered plasma AVP.

Adrenal Glands↗
PubMed1997

Effects of various beverages on the hormones involved in energy metabolism during exercise in the heat in previously dehydrated subjects.

The objective of our study was to examine the effects of beverage content on hormone responses involved in fuel substrate metabolism (catecholamines, insulin and glucagon) in previously dehydrated subjects exercising at a moderate intensity in the heat. Six healthy men walked for 60-min on five occasions at 50% maximal oxygen uptake in a warm environment (dry bulb temperature 35 +/- 0.2 degrees C, relative humidity 20%). On each occasion, the subjects were dehydrated before exercise (loss of 2% body mass) by passive controlled hyperthermia, which led to a reduction in plasma volume (PV) of about -5% to -9%. In one session, the subjects exercised without rehydration (Dh). In the other sessions, four beverages (650 ml) were given just before the exercise: mineral water (W), a 60 g x l(-1) glucose and 1.2 g x l(-1) NaCl solution (GS), a 60 g x l(-1) maltodextrin solution, and a 60 g x l(-1) maltodextrin and 1.2 g x l(-1) NaCl solution. Compared to Dh and W, carbohydrate supply with or without NaCl induced a higher glycaemia (P < 0.05), a reduced increase in plasma adrenaline concentration (P < 0.05) and a higher plasma insulin concentration (P < 0.05), which lowered plasma free fatty acids and glycerol concentrations (P < 0.05). The lesser increase in plasma noradrenaline concentrations observed during GS compared to Dh and W sessions can be explained by a larger correction in PV which might have induced better haemodynamic conditions. However, the increase in plasma glucagon with carbohydrate supply--compared to Dh and W (P < 0.05)--remains unexplained.

Adult↗