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Biomedical subjects

P Contreras

Publications and source records attributed to P Contreras.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Insulin resistance: a frequent phenomenon in clinical practice].

This review is focused on the diagnostic, clinical and therapeutic aspects of insulin resistance relevant to the clinician. The observed phenomenon of the wide variability of insulin sensitivity in clinically healthy subjects is discussed; qualitative and quantitative aspects of the methodologies currently used for the assessment of insulin sensitivity in the clinical setting are dealt with, as well as their applicability to day-to-day clinical care. The medical consequences of hyperinsulinemia, including dyslipidemia, hypertension coronary artery disease and ovarian hyperandrogenism are likewise discussed. A panoramic view of the various clinical presentations of insulin resistance is also offered, including clinical elements for suspicion, as well as an account of the prevalent, less-prevalent and rare disorders harboring the phenomenon of insulin resistance. The final topic of the review is a novel discussion on the therapeutic possibilities in insulin resistance disorders, including treatment with hormones and antihormones.

Adolescent↗
PubMed1991

[Insulin sensitivity: absence of sexual differences when expressed as a function of lean body mass].

The hyperinsulinemic, euglycemic clamp technique was used to test the hypothesis that--when expressed per kilogram of lean body mass--there is a sex-difference in peripheral insulin-mediated glucose disposal (M), as proposed in the literature. Lean body mass was assessed with tetrapolar bioelectric impedance analysis. We studied 15 normal subjects (volunteers with normal glucose tolerance and body mass indices between 20-25 kg/m2) of both sexes, 9 women and 6 men, of 2 age-groups, 20-30 year-old and 40-50 year-old. Men and women were similarly aged (33.3 +/- 3.8 and 33.3 +/- 3.8 years, respectively). Body mass indices were similar in both sexes (22.5 +/- 0.6 in women and 23.6 +/- 0.7 in men, NS) but percentages of fat mass were not (29.4 +/- 1.2 in women and 20.6 +/- 1.6 in men, p less than 0.001). As no difference in M (mg of glucose metabolized per kilogram of body weight per minute) between age-groups was found (6.4 +/- 0.8 and 6.8 +/- 1.2 mg/kg/min, NS) the data from these 2 age-groups were pooled. When M values obtained in both sexes were compared no differences were found (7.1 +/- 1.5 mg/kg/min in women and 6.3 +/- 0.6 in men, NS). Similarly, when M was expressed in function of the prevailing insulin levels attained during steady-state, M/l, no differences were disclosed (8.98 +/- 2 mg/kg/min/microIU insulin in women and 7.8 +/- 1.2 in men, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Idiopathic hypoparathyroidism, a syndrome with various clinical expressions: analysis of 10 cases].

We report 10 patients with primary hypoparathyroidism. Age at onset varied from 7 months to 52 years (mean 28); 7 were female. Diagnosis was established at a mean of 4.1 years after the appearance of clinical manifestations. Unexplained hypocalcemia (mean 5.3 mg/dl) and hyperphosphatemia (mean 6.4 mg/dl) were present in all patients. Prevalent symptoms included tetany (9 patients), seizures (5) and hypocalcemic cataracts (4). Clinical manifestations may be grouped into 5 types 1) tetany; 2) seizures; 3) other neurologic disorders (basal ganglia calcification, pseudotumor of the brain, ataxia, nystagmus, hypertonus, paresis); 4) disorders of the lens including fully developed cataracts and 5) skin alterations like psoriasis and others. Some of these run on acute course (seizures, tetany), others a subacute one (skin alterations) while others are rather chronic (cataract and other neurologic disorders). Seizures and electroencephalographic disorders predominate in younger patients while tetany is more prevalent in older subjects.

Adult↗
PubMed1989

[Adrenal hyperplasia of late onset: optimization of therapy by measuring the circadian variation of serum 17-OH-progesterone].

A 19 yr-old female patient with the diagnosis of late onset adrenal hyperplasia was treated since age 15 with different glucocorticoid preparations and dosage schedules plus spironolactone. In spite of a very good response in terms of amelioration of their hirsutism she experienced cushingoid manifestations associated with adrenal suppression. To overcome these side effects the patient was placed on hydrocortisone 20 mg at 8 AM plus spironalactone 50 mg q.i.d. Cushingoid features vanished and response to cosyntropin (ACTH 250 ug i.m.) was reestablished. To better ascertain the effects of this treatment we studied the circadian variation in serum 17-OH progesterone after hydrocortisone was administered at 8 AM and compared it with circadian variations under basal conditions or after late-evening (11 PM) administration of hydrocortisone, 20 mg. The early morning administration of hydrocortisone was unable to prevent the nocturnal elevation of 17-OH-progesterone in spite of normal levels from 9.30 AM to 3 AM. This nocturnal peak was associated with a slightly blunted nocturnal elevation of serum cortisol. In contrast, the late evening administration of hydrocortisone was able to suppress 17-OH-progesterone to within normal levels during all day. Serum cortisol during late evening therapy was not different from that observed during early morning administration (12.2 +/- 13.1 vs 9.9 +/- 11.3 micrograms/dl, p = 0.53), yet the corresponding 17-OH-progesterone levels were much lower (0.8 +/- 0.6 vs 5.9 +/- 6.9 ng/ml). We conclude that individualization of therapy is essential in patients with late-onset adrenal hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1985

Autoradiographic distribution of [3H]dexoxadrol (a phencyclidine-related ligand) binding sites in rat and human brain.

[3H]dexoxadrol, a dissociative anesthetic, binds with high affinity to specific sites in rat brain (membrane binding and light microscopic autoradiography). Various phencyclidine (PCP) analogues compete for [3H]dexoxadrol sites in a slightly different manner than against [3H]PCP binding sites. As for [3H]PCP binding, [3H]dexoxadrol binding sites are highly concentrated in brain regions such as the cortex and the hippocampus. However, other areas such as the hypothalamus are enriched only in [3H]dexoxadrol binding sites. This suggests that [3H]dexoxadrol binds to PCP-related sites in certain brain regions but not in others. In the human forebrain, [3H]dexoxadrol binding sites are distributed as in the rat brain and mainly found in the caudate, putamen and cortex.

Animals↗
PubMed1985

Adrenal rest tumor of the liver causing Cushing's syndrome: treatment with ketoconazole preceding an apparent surgical cure.

Ketoconazole, an imidazole derivative known to inhibit cytochrome P450-dependent adrenal enzymes was given to a patient with a functioning adrenal rest tumor of the liver in preparation for surgery. The drug was administered in a stepwise manner for 42 days starting with 400 mg and reaching 1 g the last 4 weeks of the trial. Clear clinical improvement was evident early in the trial and was associated with evidence of amelioration of her hypercortisolism and striking changes in serum and urinary levels of steroid hormones and metabolites. Sex steroids in serum and urine fell dramatically from the first day to the end of the trial. Urinary 17-ketosteroid excretion fell from a basal average of 139 mg/24 h to near normal levels within a week of therapy; serum testosterone fell from a basal level of 2.4 to 0.18 ng/ml; serum 17 beta-estradiol fell likewise from 1096 to 150 pg/ml. In contrast, cortisol levels in serum and urine increased in the first 2 weeks of the trial and subsequently fell to values below the basal levels. Similarly, serum 17 alpha-OH-progesterone levels increased 63% above the basal levels by day 6 of the trial and declined afterwards. Nine months after successful tumor resection the patient is apparently cured as judged by steroid hormone levels and physical appearance. We conclude that ketoconazole was effective in blocking tumoral steroidogenesis which resulted in clinical benefit.

11-Hydroxycorticosteroids↗
PubMed1983

Influence of thyroid hormone on the in vitro translational activity of specific mRNAs in the rat heart.

The influence of thyroid hormone on the translational activity of specific cardiac mRNA was determined by in vitro translation of RNA isolated from the heart of normal, hypothyroid, and 3,3',5-triiodo-L-thyronine-injected hypothyroid rats. Proteins synthesized in vitro in the presence of [35S]methionine were separated by two-dimensional gel electrophoresis and quantitated by a novel scanning procedure using digital matrix photometry. A total of 421 translational products were detected by fluorography and changes in the predominance of 12 of these were influenced by the thyroid state of the animals. The relative predominance of 8 species was increased in euthyroid animals, whereas 4 translational products were increased in hypothyroid animals. The majority of these thyroid hormone-related alterations occurred in spot pairs of similar molecular weights, but slightly different isoelectric points. In contrast, the relative predominance of mRNAs coding for the major contractile proteins, light chain 1, light chain 2, tropomyosin, actin, and myosin heavy chain was not altered by the thyroid status of the animals. The relative levels of these abundant mRNA species remained unaltered in spite of a thyroid hormone-related increase in total RNA levels. In vivo effects of thyroid hormone on cardiac RNA levels are complex. In addition to a general increase in total RNA and mRNA levels, increases or attenuations in the predominance of a small number of specific mRNA species are observed when euthyroid and hypothyroid animals are compared.

Animals↗
PubMed1983

Augmentation of ACTH-releasing activity of synthetic corticotropin releasing factor (CRF) by vasopressin in women.

In order to study the interaction between vasopressin (VP) and hypothalamic corticotropin releasing factor (CRF) on the release of ACTH, VP and CRF were administered separately and in combination to normal cycling women. The combined hormones raised plasma ACTH levels higher than the sum of the separate responses and 5 times more than CRF alone. This study reveals for the first time synergism between VP and CRF in their ACTH releasing effects in humans.

Adrenocorticotropic Hormone↗