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Biomedical subjects

G Perez

Publications and source records attributed to G Perez.

At least 91 records · Page 5Linked to original sources
PubMed1987

The making of an adolescent clinic.

This paper addresses the nationwide need for comprehensive health care services directed toward adolescents, outlining a multidisciplinary team program designed to provide such services. The national problem of teenage pregnancy is discussed, and the multidisciplinary team's success with family planning counseling is described. The authors strongly encourage the development of more school- or community-based clinics based on a comprehensive health care team model.

Adolescent↗
PubMed1986

Pharmacokinetics of ranitidine in patients with renal failure.

The pharmacokinetics of ranitidine were studied in ten patients with renal failure (creatinine clearance, 6-54 mL/min) after intravenous (IV) (50 mg) and oral doses (150 mg). After oral administration, peak plasma concentrations of 378-808 ng/mL were obtained in two to six hours. Plasma concentrations declined very slowly and concentrations greater than 100 ng/mL were obtained for 16 to 20 hours after the dose. The elimination half-life following oral administration was 8.5 +/- 2.8 hours (standard deviation [SD]), and the bioavailability of ranitidine was 43.3% +/- 10.5%. After IV administration, the elimination half-life, plasma clearance, renal clearance, and volume of distribution were 7.0 +/- 1.0 hours, 170 +/- 38 mL/min, 36.0 +/- 25.0 mL/min, and 1.3 +/- 0.4 L/kg, respectively. About 20% of the IV dose and 9% of the oral dose were recovered unchanged in urine. There was a significant correlation between the renal clearance of ranitidine and creatinine clearance (r = .74, P less than .05) after IV administration. The elimination half-life in patients with renal insufficiency is about three times greater than that reported in the literature for healthy subjects. Similarly, the plasma clearance in these patients is about 20% of that reported in healthy subjects. The results indicate that ranitidine elimination is appreciably reduced in renal failure and that an adjustment of dose in patients with renal failure is warranted. A dose of 75 mg bid may be adequate in maintaining the therapeutic plasma concentrations that are required for adequate H2-blocking activity.

Aged↗
PubMed1986

An in vitro and in vivo study on mutagenic activity of fluoranthene: comparison between cytogenetic studies and HPLC analysis.

The polycyclic aromatic hydrocarbon, fluoranthene (FT), has been shown to induce SCEs in vitro in CHO cells in the presence of metabolic activation. Negative results were obtained in vivo in mice. The HPLC analysis performed to investigate the presence of metabolites of FT both in the serum of treated mice and in culture medium of CHO cells confirmed some differences between in vitro and in vivo metabolism.

Animals↗
PubMed1986

Cephalic magnetic resonance imaging of boxers. Preliminary results.

A prospective study of 52 boxers, 20-60 years, 13 of them amateurs and 39 professionals, has been made using magnetic resonance imaging (MRI) at 0.15 T. Twelve of the boxers were still active, while the other 40 had retired after about 10 years of boxing. Multi-slices in two planes without gap were performed using T1 and T2 weighted sequences. The findings were correlated to the number of matches, the number of knock outs, the severity of head trauma, the style of the boxer, and to the clinical findings and the findings at EEG. There was a good correspondence between the presence of lesions and the style of the boxer. The changes noted--mainly atrophic--occurred among those with capacity to 'stand punishment'. MRI offers an opportunity to evaluate the effect of trauma and the information obtained may be used to prevent disabilities among boxers.

Adolescent↗
PubMed1985

Protoplast fusion as a tool for genetic analysis in Cephalosporium acremonium.

Protoplasts of nutritionally complementary strains of Cephalosporium acremonium were fused and plated onto media which supressed the growth of both parents. The regenerating colonies were used for genetic analysis and were found to be of two types, stable haploid recombinants and unstable heterozygotes (aneuploids and/or diploids). Analysis of these colonies provided evidence for eight linkage groups and a relatively high rate of mitotic crossing-over. The gene order for three of the markers on one linkage group was also determined.

Acremonium↗
PubMed1985

Pentamidine treatment of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. Association with acute renal failure and myoglobinuria.

A 31-year-old man with acquired immunodeficiency syndrome and biopsy-proved Pneumocystis carinii pneumonia developed acute renal failure, elevated creatinine kinase levels, and myoglobin in both serum and urine while being treated with pentamidine. The patient was receiving no other nephrotoxic medications at the time, and these unusual complications were directly related to the pentamidine.

Acquired Immunodeficiency Syndrome↗
PubMed1983

[Acute postoperative pulmonary edema in the coronary patient: effects of myocardial ischemia].

In order to evaluate the incidence of myocardial ischaemia in patients who developed acute pulmonary oedema during the immediate post-operative period, continuous monitoring of the electrocardiogram by the Holter method was used in 200 consecutive patients with coronary artery disease. Fourteen of these patients exhibited ST segment depression during the post-operative period and 13 during surgery. Nine patients developed acute pulmonary oedema immediately after the operation and in 7 cases the oedema was preceded by myocardial ischaemia. A continuous nitroglycerin infusion brought about regression of the pulmonary oedema in 8 cases. One patient died despite treatment. These findings underline the part played by myocardial ischaemia in the pathogenesis of acute post-operative pulmonary oedema in patients with coronary artery disease.

Acute Disease↗
PubMed1982

[Combined touching and palpation in parathyroid surgery].

The parathyroid glands may be located anywhere and hidden in the thick thyroid gland sheath, so that the duration of parathyroidectomy is impossible to predict. For accurate and rapid identification and assessment of the nodule to be dissected, the authors advocate a two-finger method: one index finger palpates the whole length of the posteromedial segment of the thyroid sheath, while the other index finger penetrates into the thyroid cavity. Fourteen parathyroid adenomas and 39/40 hypertrophied glands were detected by this method. Results were negative in 12 cases with unconfirmed biological diagnosis of hyperparathyroidism.

Humans↗
PubMed1982

[A fourth tone and latent cardiac insufficiency in ischemic heart disease].

An assessment was made of the fourth heart sound as a non-invasive clinical and instrumental aid in the diagnosis of latent cardiac insufficiency. The sound was recorded in various decubitus positions in a series of healthy subjects and patients with recent and past infarction, under basal conditions, after exercise on the cycle ergometer, and after digitalis i.v. Persistence of the fourth sound in the standing position was noted in nearly all infarct patients, while its incidence decreased significantly after digitalis. It is felt that this finding can be interpreted as evidence of the non-existence of latent heart failure. Its further investigation and correlation with other invasive and non-invasive instrumental examinations is proposed.

Adult↗
PubMed1982

State of metabolic control determines role of epinephrine-glucagon interaction in glucoregulation in diabetes.

Epinephrine (0.1 micrograms.kg-1.min-1) was infused with or without somatostatin (0.1 microgram.kg-1.min-1) in six depancreatized dogs, studied under normo- and hypoinsulinemia to determine whether the participation of glucagon in epinephrine-induced hepatic glucose overproduction is governed by the degree of metabolic control. When normoglycemia was achieved by basal intraportal insulin replacement, insulin levels remained constant during the epinephrine infusion, and there was a twofold increase in extrapancreatic immunoreactive glucagon (eIRG) and glucose production (Ra). Although eIRG increments were prevented by somatostatin, the increase in Ra was undiminished, indicating that epinephrine can act independently of glucagon as in normal animals. During subbasal intraportal insulin infusion in the depancreatized dogs, insulin levels remained 35% lower than with basal replacement, and the animals were hyperglycemic. Epinephrine induced a similar twofold increase in eIRG as during normoglycemia, and again this rise was prevented by somatostatin. There was a significantly greater, threefold increase in Ra with epinephrine when the animals were hyperglycemic. This exaggerated response to epinephrine was not seen during eIRG suppression by somatostatin, suggesting that glucagon participated in the epinephrine-induced hepatic glucose overproduction when the depancreatized dogs were in poor metabolic control, as seen previously in alloxan-diabetic dogs. However, in the depancreatized, unlike in the alloxan-diabetic dogs, epinephrine-induced glucagon release was small. Thus, hypoinsulinemia appears to sensitize the liver to eIRG during epinephrine infusion. The fact that epinephrine induces hyperglycemia both in physiology and diabetes could indicate an important role in enhancing glucose transport in insulin-insensitive tissues.

Animals↗
PubMed1981

Importance of glucagon in mediating epinephrine-induced hyperglycemia in alloxan-diabetic dogs.

In normal dogs epinephrine stimulates glucose production (Ra) independently of glucagon. To investigate the role of this interaction in diabetes, epinephrine (0.1 micrograms . kg-1 . min-1) was infused for 90 min in five alloxan-diabetic dogs in the presence or absence of somatostatin (0.1 micrograms . kg-1 . min-1). In response to epinephrine, glycemia rose by 40% reflecting a near maximal (122%) increase in Ra. Plasma glucagon (IRG) rose to 953 pg/ml, whereas insulin (IRI) increased minimally. When somatostatin was infused with epinephrine to prevent the rise of IRG and IRI, there was only a marginal increase of glucose concentration (12%) and production (38%). The effect of somatostatin was reversed by infusing glucagon (10 ng . kg-1 . min-1) together with epinephrine and somatostatin into five additional alloxan-diabetic dogs. Increments in IRG, glycemia, and Ra were fully reestablished. A 100% FFA increase was observed in all three groups, indicating that the lipolytic effect of epinephrine was independent of glucagon. In conclusion, in diabetic dogs, in contrast to normal dogs, epinephrine induced a marked and prolonged increase in glucose concentration and production mostly through a stimulation of IRG secretion.

Alloxan↗
PubMed1981

Chromatographic pattern of extrapancreatic glucagon and glucagon-like immunoreactivity before and during stimulation by epinephrine and participation of glucagon in epinephrine-induced hepatic glucose overproduction.

To characterize the glucagon released in response to epineephrine in depancreatized dogs, plasma samples before and during epinephrine infusion were subjected to molecular-sieve chromatography on Bio-Gel P-30 columns. The chromatographic profile for extrapancreatic immunoreactive glucagon (eIRG) revealed two glucagon moieties of molecular weight 9,000 to 12,000. GLI of this molecular weight was released in response to epinephrine only under conditions of prevailing hyperglycemia. To determine if glucagon's participation in epinephrine-induced hepatic glucose overproduction in diabetes was dependent upon the degree of metabolic control, six conscious depancreatized dogs were infused with epinephrine or epinphrine plus somatostatin, under conditions of prevailing hyperglycemia or normoglycemia. Under normoglycemic conditions, epinephrine stimulated eIRG release, but there was a similar rise in hepatic glucose production (Ra) with or without glucagon suppression by somatostatin. Under hyperglycemic conditions, epinephrine stimulated eIRG and GLI release, and the rise in Ra was significantly greater with epinephrine than with epinephrine plus somatostatin infusion. Thus, under conditions of good metabolic control, epinephrine increased hepatic glucose production independently of glucagon, whereas with poor metabolic control, glucagon contributed to hepatic overproduction of glucose.

Animals↗