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Biomedical subjects

P Fernandez

Publications and source records attributed to P Fernandez.

At least 91 records · Page 5Linked to original sources
PubMed1989

Time to first shock and clinical outcome in patients receiving an automatic implantable cardioverter-defibrillator.

The relation between time to first shock and clinical outcome was studied in 60 patients who received an automatic implantable cardioverter-defibrillator (AICD) from August 1983 through May 1988. The mean (+/- SD) patient age was 64 +/- 10 years, 82% were men and the mean ejection fraction was 33 +/- 13%. During follow-up, 38 patients (63%) had one or more shocks; there were no differences in age, gender distribution or ejection fraction at entry between the shock and no shock groups. Among 51 patients with coronary artery disease, 31 (61%) had one or more shocks, whereas all seven patients with cardiomyopathy had one or more shocks (p less than 0.05). Neither of the two patients with idiopathic ventricular fibrillation had shocks. Of the 13 deaths, 12 occurred during post-hospital follow-up and 1 during the index hospitalization. Of the four sudden post-hospital deaths, only one was due to tachyarrhythmia in the absence of acute myocardial infarction. All four sudden deaths and five of eight post-hospital nonsudden deaths occurred in patients who had had one or more appropriate shocks during follow-up. Eight of the nine first appropriate shocks among patients who subsequently died occurred within the first 3 months of follow-up, but the actual deaths were delayed to a mean of 14.1 +/- 13.9 months (p less than 0.05). The mean time to all deaths was 14.8 +/- 13.1 months. The ejection fraction was significantly lower among patients who died than among patients who survived (25 +/- 7% versus 35 +/- 14%, p less than 0.02), but it did not distinguish risk of first shocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Reversal of proarrhythmic effects of flecainide acetate and encainide hydrochloride by propranolol.

The use of membrane-active antiarrhythmic agents may be complicated by aggravation of existing arrhythmias or development of new drug-induced arrhythmias. Four patients, referred because of out-of-hospital cardiac arrest or symptomatic sustained ventricular tachycardia, were receiving class IC antiarrhythmic agents in an attempt to prevent inducibility of sustained ventricular tachycardia. New or worsening spontaneous arrhythmias developed while they were on flecainide acetate (n = 3) or encainide hydrochloride (n = 1) therapy. Spontaneous runs of rapid nonsustained and sustained ventricular tachycardia developed in two. Increased frequency of premature ventricular contractions and repetitive forms of ventricular ectopic activity developed in one, despite the fact that inducibility of sustained ventricular tachycardia had been prevented. Salvos and nonsustained ventricular tachycardia developed in the fourth patient. Propranolol had failed to prevent inducibility of sustained ventricular tachycardia during previous programmed stimulation studies in three of the four patients, but it reproducibly suppressed drug-induced arrhythmias that appeared only after administration of the IC agents in each patient. Suppression of the proarrhythmic effects by beta-adrenergic blockade suggests a possible interaction of these drugs with autonomic function in the genesis of the observed proarrhythmic effects. Direct pharmacologic control of proarrhythmic drug effects has not previously been reported.

Aged↗
PubMed1988

Fura-2 used as a probe to show elevated intracellular free calcium in platelets of Dahl-sensitive rats fed a high salt diet.

Elevated intracellular free calcium concentration [Ca2+]i in vascular smooth muscle cells has been implicated in the pathophysiology of hypertension. Platelet [Ca2+]i was measured using the fluorescent indicator, Fura-2, in Dahl sensitive (DS) and resistant (DR) rats given high (8% NaCl) and low (0.4% NaCl) salt diets, as well as in the spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. The aim of this study was to show whether [Ca2+]i is elevated in salt induced hypertension. Platelet [Ca2+]i and systolic blood pressure (SBP) were higher (p less than 0.001) in DS rats given a high than low salt diets. In contrast, no changes in platelet [Ca2+]i and SBP were observed in DR rats. In SHR, platelet [Ca2+]i and SBP were higher (p less than 0.001) than in the WKY rats. Platelet [Ca2+]i correlated with SBP in all groups of rats (r = 0.929; p less than 0.001, n = 38). The parallel increase in SBP and [Ca2+]i in the DS high salt rats and the SHR suggests that an increased [Ca2+]i is involved in the pathophysiology of hypertension in the two models which differ with respect to the pathogenesis of their hypertension. This increase in [Ca2+]i therefore seems to reflect an abnormality in [Ca2+]i handling in hypertension regardless of its cause.

Animals↗
PubMed1988

Characteristics of entrainment during autodecremental atrial and ventricular stimulation.

The entrainment characteristics of orthodromic circus movement tachycardias occurring during autodecremental atrial and ventricular stimulation were studied in 9 patients with manifest Wolff-Parkinson-White syndrome. The phenomenon occurred in 34 of 38 episodes of tachycardia during autodecremental atrial stimulation. It was not seen in 4 episodes because the first impulse penetrating the circuit terminated the arrhythmia. Invariably, the HH and VV intervals were not equal to, but longer than, the stimulus-stimulus intervals, thus not fulfilling the definition of "classic" (constant cycle length) entrainment postulated by Okumura et al. Furthermore, the first 2 of the 3 diagnostic criteria were not demonstrated and the third only could be demonstrated in 7 episodes. Tachycardia termination was achieved in all 38 episodes. Entrainment occurred during autodecremental ventricular stimulation in 79 of 80 episodes, with the AA and H-H- intervals (when visible) being equal to the corresponding paced cycle lengths. Moreover, the intervals between the last paced ventricular beat and the first ventricular beat of the resumed tachycardia were invariably longer than the last stimulus-stimulus intervals. These characteristics were those which Okumura et al attributed to "concealed" entrainment. Tachycardia termination was achieved in 77 of 80 episodes. In summary: (1) autodecremental atrial pacing produced a specific form of entrainment that did not fulfill the "classic" definition of Okumura et al; (2) autodecremental ventricular pacing consistently produced "concealed" entrainment; and (3) autodecremental stimulation was very effective in terminating 115 of 118 (98%) of episodes of circus movement tachycardias.

Cardiac Pacing, Artificial↗
PubMed1988

Absolute bioavailability of cefixime in man.

In a four-way cross-over study, the absolute bioavailability of cefixime was determined in 16 healthy volunteers. Each subject received a single 200-mg dose as an intravenous (IV) and oral solution, and 200-mg and 400-mg capsule doses of the drug. Blood and urine samples were collected for 24 hours after each dose. Cefixime was well tolerated after IV and oral doses of the drug and no serious drug-related adverse effects were observed. The maximal serum concentration (Cmax) of cefixime following the 200-mg oral solution and 200-mg and 400-mg capsule doses were 3.22, 2.92, and 4.84 micrograms/mL, respectively. Mean area under the serum concentration time curves (AUC) following the IV, 200-mg oral solution, and 200-mg and 400-mg capsule doses were 47.0, 26.0, 23.6, and 39.4 micrograms.hr/mL, respectively. Mean elimination half-life values of the drug were comparable after oral and IV doses, ranging from 3.2 to 3.5 hours. Based on serum AUC values, the absolute bioavailability of cefixime was 52.3%, 47.9%, and 40.2% after the 200-mg oral solution, 200-mg capsule and 400-mg capsule doses, respectively. Respective ratios based on 24-hour urinary recovery data were 44.7%, 41.7%, and 40.5%. Therefore, the results show that the percent of cefixime adsorbed after 200-mg and 400-mg oral doses was similar.

Administration, Oral↗
PubMed1988

The role of vascular Na,K-ATPase activity in salt induced hypertension in Dahl rats.

The role of endogenous inhibitors of vascular Na,K-ATPase (NKA) activity in salt-induced hypertension was evaluated by examining the inhibition of 86Rb+ uptake in aortae of Sprague-Dawley (SD) rats by plasma derived from Dahl sensitive (DS) and resistant (DR) rats given high (8%) and low (0.4%) NaCl diet for four weeks. With 4 weeks of high salt diet DS rats demonstrated marked increase in systolic blood pressure. When compared to DR and DS rats on low salt diet, plasma from DR and DS rats on high salt diet had a stimulatory (not inhibitory) effect on NKA as measured by 86Rb+ uptake of SD rat aortae. As compared to DR rats plasma from DS rats on similar salt intakes had a stimulatory effect on NKA of SD rats. Aortae from the 4 groups of Dahl rats were also assayed for NKA activity. Total, ouabain-sensitive and ouabain-insensitive NKA activities were higher in DS rats as compared to DR rats on similar salt diet. Both DS and DR rats on high salt diet had higher NKA activity than on low salt diet. There was no evidence for a decrease in vascular sodium pump activity accompanying hypertension. Furthermore, high salt diet did not increase plasma Na,K-ATPase inhibitory activity in DS rats when hypertensive. These results suggest that NKA inhibition plays a minor role if any in hypertension of DS rats, in contrast to what has been hitherto believed.

Animals↗
PubMed1987

Pharmacologic approaches to management of arrhythmias in patients with cardiomyopathy and heart failure.

Interactions between disordered cardiac rhythm and abnormal cardiac hemodynamic function are well recognized. Demonstrations of this relationship include the relationship between prognostic significance of ventricular ectopy and left ventricular ejection fraction, impairment of ventricular function in association with loss of atrial systole in disease states, increased risk of potentially lethal arrhythmias in the myopathic ventricle, and the evolution of advanced grades of ventricular arrhythmias in acute heart failure. With the development of newer and more potent antiarrhythmic agents, in conjunction with drugs that can improve the failing circulation, it is now possible to clarify these interrelationships and perhaps develop new strategies for clinical management.

Anti-Arrhythmia Agents↗
PubMed1986

Partial cDNA sequence encoding a globular domain at the C terminus of the rat cartilage proteoglycan.

We have isolated and sequenced a cDNA clone of 872 base pairs from the 3' end of the mRNA for the large cartilage specific proteoglycan from rat. Identification was confirmed by a comparison with published protein sequence. Hybridization analysis shows the presence of an 8-9-kilobase mRNA for this proteoglycan in rat and chick sternal chondrocytes and rat chondrosarcoma cells, but not in RNA from rat fibroblasts, vitamin A-treated chick chondrocytes, chick crop, or bone. The carboxyl portion of the proteoglycan is deduced to terminate in a globular domain, which includes a region homologous to a chick hepatic lectin, and is possibly involved in binding to N-acetylglucosamine. The clone extends into a region where serines are clustered, probably the start of the chondroitin sulfate-rich region.

Amino Acid Sequence↗
PubMed1985

Effect of somatostatin on small intestine enzyme activities in rat and chick.

The influence of somatostatin injection on intestinal disaccharidase and alkaline phosphatase activity in rat and chick was investigated. Disaccharidase and alkaline phosphatase activities of rat and chick homogenates were not modified. In rat the activities of mucosal brush-border maltase and sucrase were significantly increased. In chick brush-border a significant increase of duodenal mucosal activity and duodenal and jejunal sucrase activity is observed.

Alkaline Phosphatase↗
PubMed1985

Mechanisms maintaining a low-pH microclimate in the intestine.

The presence of an unequilibrated region adjacent to the mucosal surface of the small intestine has long been suggested. Controversy remains as to the characteristics of this region. This study was designed to further define these characteristics. Our studies demonstrated by two independent methods, pH electrode measurement and dye indicator, that a low-pH compartment does exist at the surface of the intestine. The thickness of this microclimate was estimated to be 700 microns, comparable with that described for the unstirred water layer. Maintenance of the low-pH compartment is due to the presence of a mucus coating rather than hydrogen ion secretion. We postulate that the mucus functions as an ampholyte and restricts hydrogen ion movement in its matrix. The acidic microclimate, unstirred water layer, and the mucus coating might in fact represent a common phenomenon.

Animals↗
PubMed1985

Musculoskeletal manifestations in hemodialysis patients.

One hundred and two consecutive patients receiving maintenance hemodialysis were interviewed and examined to analyze their musculoskeletal problems. Radiographic abnormalities of renal osteodystrophy were found in 23 and there were periarticular calcifications in 5. Only one patient had apatite associated knee arthritis and none had gout or calcium pyrophosphate deposition disease. Twenty patients had arthralgias, 3 polyarthritis, and 4 knee effusions all of which were incompletely explained. Correlations of arthralgias with radiographic findings was poor. Muscle cramps were seen in 24 patients, multiple fractures in one, symmetrical distal neuropathy in 18, and carpal tunnel syndrome in 9.

Adolescent↗
PubMed1984

Variations in monoamine contents in discrete brain regions and their concomitance with plasma corticosteroids during the day.

We determined the plasmatic corticosterone and 5-HT, NA and DA levels in the hypothalamus, amygdala, hippocampus and septum at different hours. Significant fluctuations were found to occur in the biogenic amines and corticosterone plasmatic levels. Highest levels of this hormone were detected at the end of the light period. Plasma corticosterone was found to be inversely correlated with 5-HT and DA levels of amygdala and directly correlated with hypothalamus DA level.

Amygdala↗
PubMed1981

[Idiopathic orthostatic hypotension (Shy-Drager syndrome). Clinical and hemodynamic studies of a case].

A case of idiopathic orthostatic hypotension (Shy-Drager syndrome) in a 50-year-old man is reported. The diagnosis was made after other possible causes of orthostatic hypotension had been excluded. The Authors emphasize the need for a correct diagnosis in order to adopt an adequate symptomatic therapy, and to avoid useless and often harmful treatments.

Autonomic Nervous System Diseases↗
PubMed1981

Factor structure of the Faschingbauer Abbreviated MMPI (FAM) in a psychiatric population.

Factor analysis of the Faschingbauer Abbreviated MMPI (FAM) identified factors of Absence of Distress, Depression, Low Morale, Feminine Interests, Somatization, and Extroversion. These results are consistent with previous MMPI factoranalytic studies, with the first factor being a reflected factor of major psychopathological disturbance. This reflected factor is explained as a function of the elimination of clinically invalid profiles from the analysis. Implications concerning standard profile selection procedures are discussed in light of these results.

Adult↗