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Biomedical subjects

R Vargas

Publications and source records attributed to R Vargas.

At least 127 records · Page 7Linked to original sources
PubMed1982

Ischemic cerebrovascular complications of Haemophilus influenzae meningitis. The value of computed tomography.

In an effort to define the value of computed tomographic (CT) scanning in assessment of cerebral involvement in children with severe Haemophilus influenzae meningitis, we studied 12 children who had focal neurologic deficits on admission or within the early days of illness. The CT scan reliably excluded abscess and cerebritis and suggested ischemic cerebrovascular lesions in 11 of 12 children. Scans performed early in the hospital course generally showed low-density lesions occurring in a vascular distribution without detectable mass effect or enhancement. Later in the clinical course there was consistent enhancement of gray matter or diffuse enhancement in the area of the vascular lesion. The duration of symptoms of meningitis ranged from five to 21 days (mean, 13 days) and appeared to predispose to these vascular lesions. A CT scan consistent with infarction of brain parenchyma occurred predictably in patients with persistent focal neurologic deficits and was correlated with poor outcome.

Brain Ischemia↗
PubMed1981

Role of elongation factor 1 in the translational control of rodent brain protein synthesis.

The translational control of protein synthesis during early postnatal neural development and aging was examined in the mouse and the rat. The activity of brain elongation factor 1 (bEF-1) was found to decrease exponentially with age and to decline parallel to the age-dependent decrease in total protein synthesis in both rodents. This decrement in bEF-1 activity fell within the range of reported age-related decreases in protein synthesis in in vitro systems. The factor was present in multiple forms; the lighter species predominated in older animals, whereas the young light form apparently disappeared with increasing age, and was replaced by other arising from the heavy form. Elongation factor 1 derived from young brains functioned as a rate-limiting component in polypeptide synthesis in previously saturated adult systems. The data suggest that bEF-1 has an important modulatory effect on total brain protein synthesis.

Aging↗
PubMed1977

On the question of an interaction between sulindac and tolbutamide in the control of diabetes.

The effect of sulindac and tolbutamide on the control of diabetes was studied in 12 tolbutamide-treated maturity-onset diabetics with stable glycemic control. After one week of hospitalization on a metabolic ward for adjustment of diet and activity, the patients were treated with sulindac, 200 mg twice daily for one week. The time-to-peak plasma tolbutamide concentration was 3.1, 3.1, and 3.2 hr, respectively, after tolbutamide alone, after the first dose of sulindac, and after sulindac for a week. The areas under the plasma tolbutamide curve were 23.68, 22.10, and 22.78 for the same periods. The half-life for plasma tolbutamide was 7.46, 7.15, and 7.38 hr, respectively. None of the differences were statistically significant. The mean fasting plasma sugar was lower after the sulindac treatment (from 12.5 to 112.9 mg/100 ml, p less than 0.05), but the postprandial values increased slightly (from 137.7 to 142.6). It was concluded that there was no clinically significant interaction between sulindac and tolbutamide.

Adult↗
PubMed1977

Guanabenz in essential hypertension.

Fifty-five patients with mild to moderately severe essential hypertension were treated with guanabenz (2, 6-dichlorobenzylidene aminoguanidine acetate) in doses from 4 to 16 mg twice daily in a randomized, placebo-controlled study. The patients treated with placebo in the initial phase of the study were subsequently treated with guanabenz. The mean arterial pressure in the guanabenz group decreased from 130.6 to 107.6; that in the placebo group decreased from 129.6 to 126.6 standing and from 126.6 tp 109.9 and 128.8 to 120.5, respectively, supine. The principle adverse effects included sedation, dry mouth, weakness, and tiredness. Of the guanabenz-treated patients 84% had sustained decrease in supine diastolic blood pressure of 10 mm Hg or more, whereas in the placebo-treated patients only 32% had such a response. There was no significant orthostatic hypotension. Guanabenz thus appears to be an effective antihypertensive drug in patients with mild to moderately severe hypertension.

Adult↗
PubMed1977

Efficacy and acceptability of different dosage schedules of clonidine.

In 12 hospitalized patients with hypertension, clonidine 3 times a day led to better control of blood pressure than did the same total dose administered once daily. Compared to the uniform control of blood pressure on divided dose regimen, the single daily 8 P.M. dose led to wider fluctuations and inadequate control 18 hr after dosing. However, 10 of the 12 patients preferred the single daily dose at 8:00 P.M. to the divided dose regimen because of no drowsiness during the day. In 2 patients administration of clonidine twice daily resulted in better control of blood pressure than that during the single or thrice-daily dose regimens. Since there appeared to be a correlation between the dose and the duration of adequate blood pressure control, administration of clonidine twice a day with a larger dose at bedtime and a smaller dose before noon could limit unwanted drowsiness and combine the convenience of less frequent dosing with superior blood pressure control.

Adult↗
PubMed1976

Mesangiocapillary glomerulonephritis with dense "deposits" in the basement membranes of the kidney.

Amongst 125 patients with mesangiocapillary glomerulonephritis (MCGN), 19 showed continuous intramembranous dense "deposits" (IDD). Most were children or young adults. Two patients had partial lipodystrophy. Eleven had a consistently low plasma concentration of C3; only three, however, had an initial low plasma concentration of C4, which rose and then remained normal in two. Tests for the C3 nephritic factor were positive in thirteen patients, and plasma C1q was normal in 8 out of 11 cases investigated. Ten out of twelve (seven of them with low plasma C3) showed C3 deposition by immunofluorescence in the glomerular tuft. This was also demonstrated in some instances in Bowman's capsule and tubular basement membranes. Stains for IgG, IgA, C4 and C1q were negative in all, whereas stains for IgM and fibrin were weakly positive in the glomeruli of three and eight cases repectively. Eight patients went into terminal renal failure over an average of thirty-three months and required hemodialysis or transplantation. MCGN with IDD is an uncommon pattern of renal response to injury, which involves activation of the alternate pathway of the complement system and has a poor short term prognosis. The association with partial lipodystrophy and C3-splitting activity suggests a primary complement abnormality.

Adolescent↗
PubMed1975

[Hypercoagulability in the nephrotic syndrome of children].

Several coagulation factors were studied in twenty children less than 16 years old, bearing nephrotic syndrome. Four of them were in remission. In nephrotic syndrome there is hypercoagulability. Coagulations factors such as fibrinogen, platelet factor III, prothrombin time, and factor V are markedly altered, and to a lesser degree, total number of platelets. Fibrin degradation products factors II, VII, X and VIII are also altered. During remission, all of them improve or become normal. In no case fibrin breakdown products were found in the blood. However, if found in urine, they would be considered as a pronostic index in nephropaties. Although etiologic factors remain unknown for most of the above-mentioned alterations, increased fibrinogen synthesis, decreased fibrinolytic plasms activity and renal damage have been demonstrated.

Adolescent↗