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H Valdivia

Publications and source records attributed to H Valdivia.

11 recordsLinked to original sources
PubMed2006

In vivo left ventricular functional capacity is compromised in cMyBP-C null mice.

Cardiac myosin binding protein-C (cMyBP-C) is a thick filament-associated protein that binds tightly to myosin and has a potential role for modulating myocardial contraction. We tested the hypothesis that cMyBP-C 1) contributes to the enhanced in vivo contractile state following beta-adrenergic stimulation and 2) is necessary for myocardial adaptation to chronic increases in afterload. In vivo pressure-volume relations demonstrated that left ventricular (LV) systolic and diastolic function were compromised under basal conditions in cMyBP-C(-/-) compared with WT mice. Moreover, whereas beta-adrenergic treatment significantly improved ejection fraction, peak elastance, and the time to peak elastance in WT mice, these functional indexes remained unchanged in cMyBP-C(-/-) mice. Morphological and functional changes were measured through echocardiography in anesthetized mice following 5 wk of aortic banding. Adaptation to pressure overload was diminished in cMyBP-C(-/-) mice as characterized by a lack of an increase in posterior wall thickness, increased LV diameter, deterioration of fractional shortening, and prolonged isovolumic relaxation time. These results suggest that the absence of cMyBP-C significantly diminishes in vivo LV function and markedly attenuates the increase in LV contractility following beta-adrenergic stimulation or adaptation to pressure overload.

Adrenergic beta-Agonists↗
PubMed1996

[Ileopsoas muscle abscess].

The experience with 14 patients affected of abscess of the psoas iliac muscle, attended at a general hospital through 1983-1995 is analized. This is a disease difficult to diagnose; it is usually diagnosed after a long delay (average of 45 days); it affects mainly women (rate F/M 11: 3), with a mean age in our patients of 50.4 years (14-79). The most frequent sign was fever (86% of the patients). Pain involving the thigh was present in 57%, and the psoas' sign in 36%. Even when this sign was present it did not always orient to the correct diagnosis. In two cases, the abscess was considered primary and in twelve it was associated to osteomyelitis, urinary tract infection or tumor (cancer of colon, metastasis in small bowell, melanoma and cancer of cervix). Gram smears and cultures of the material obtained by puncture were useful for detecting the causal germ, but blood cultures were inferior in yielding it (1 positive in 8 cases). Gram positive germs were predominant (Staphylococci coag. + in 4, Staph. coag.--in one, beta hemolytic Streptococci, 1). Gram negative germs were associated with urinary tract infections and staghorn lithiasis. In one case the etiology was TBC. Abdominal TAC was diagnostic when correlated with clinical data in 100% of the cases; ecography was diagnostic in only 2 of 11 cases. Patients were treated with antibiotics and percutaneous drainage; the only deaths occurred in patients with cancer.

Adolescent↗
PubMed1991

The brain ryanodine receptor: a caffeine-sensitive calcium release channel.

The release of stored Ca2+ from intracellular pools triggers a variety of important neuronal processes. Physiological and pharmacological evidence has indicated the presence of caffeine-sensitive intracellular pools that are distinct from the well-characterized inositol 1,4,5,-trisphosphate (IP3)-gated pools. Here we report that the brain ryanodine receptor functions as a caffeine- and ryanodine-sensitive Ca2+ release channel that is distinct from the brain IP3 receptor. The brain ryanodine receptor has been purified 6700-fold with no change in [3H]ryanodine binding affinity and shown to be a homotetramer composed of an approximately 500 kd protein subunit, which is identified by anti-peptide antibodies against the skeletal and cardiac muscle ryanodine receptors. Our results demonstrate that the brain ryanodine receptor functions as a caffeine-sensitive Ca2+ release channel and thus is the likely gating mechanism for intracellular caffeine-sensitive Ca2+ pools in neurons.

Animals↗
PubMedDate not supplied

[Insulin transference in 198 patients from 6 Latin American countries].

A multicentric, comparative, single-blind, randomized, prospective study was designed to evaluate the efficacy and safety of the transference from animal source insulins to rDNA human insulin in Latinamerican insulin-requiring diabetic patients. All the patients were on animal insulin for at least two months before inclusion. The patients were evaluated at the beginning, and at two and six weeks after inclusion. A total 198 patients completed the study and were considered evaluable: 94 were assigned to the animal insulin group, and 104 to the human insulin group. There were no statistically significant baseline differences between groups. The only statistically significant difference, detected at the end of the study, was a reduction in fasting blood glucose level in the human insulin group (animal insulin 212 +/- 95.3 initial vs 193 +/- 78.3 mg/dL final, p = 0.18; human insulin 198 +/- 86.8 vs 169 +/- 71.7, p = 0.025). There were no statistically significant initial-final changes in the rest of the parameters evaluated although a trend of reduction in glycohemoglobin levels was observed in both groups. There were more episodes of mild hipoglycemia in the human insulin group, and only one episode of severe unwarned hypoglycemia in the same group. We conclude that the transference of insulins in Latinamerican diabetic patients is effective and reasonably safe (with a dose adjustment when the change is made).

Adolescent↗