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Biomedical subjects

J Salazar

Publications and source records attributed to J Salazar.

At least 19 recordsLinked to original sources
PubMed1992

Deficient production of nitric oxide induces volume-dependent hypertension.

AIM: To study the influence of nitric oxide on renal function. DESIGN: Nitric oxide synthesis was inhibited and the effects on renal parameters were determined. METHODS: Nitric oxide synthesis was progressively blocked by the intravenous administration of increasing doses of NG-nitro-arginine methylester (L-NAME) and then (c)GMP was administered. RESULTS: The blockade of nitric oxide synthesis first induced a marked fall in urinary sodium excretion, and later, a sustained increase in mean arterial pressure. These effects were reversed by 8-bromide cGMP. Nitric oxide-dependent cGMP formation was higher in the inner medulla than in any other part of the renal parenchyma, and the inhibition of nitric oxide synthesis significantly decreased both pressure- and volume expansion-induced natriuresis. CONCLUSIONS: Both the natriuretic and vasodilator tone maintained by nitric oxide are ultimately due to the production of cGMP. Nitric oxide-induced formation of cGMP appears to be the major factor that links changes in renal medullary circulation to those of sodium excretion. Sufficient inhibition of nitric oxide synthesis to decrease sodium excretion without altering blood pressure induces volume-dependent hypertension because blood pressure is elevated by an increased sodium intake.

Animals↗
PubMed1992

[Two-dimensional and Doppler echocardiography in the non-invasive diagnosis of coronary cardiac fistula].

Two asymptomatic children with an atypical continuous murmur and a clinical diagnosis of coronary artery fistula are reported. Cross-sectional and Doppler echocardiography led to the diagnosis of a right coronary artery-right ventricule fistula in both cases, which was confirmed by coronary angiography. Surgical closure of the fistula was realized without complications.

Arteriovenous Fistula↗
PubMed1991

Cell line segregation in a 45,X/46,XY mosaic child with asymmetric leg growth.

Clinical evaluation of a 13 1/2-year-old male revealed a 4.4-cm leg length discrepancy and a small penis with a normal endocrine evaluation. Cytogenetic analysis of peripheral blood lymphocytes and skin fibroblasts derived from the back showed 45,X/46,XY mosaicism with similar percentages of 45,X cells, 36% and 30% respectively. However, two separate skin fibroblast cultures derived from the thigh and calf of the short (right) leg showed significant lack of Y-bearing cells with 100% and 80% 45,X, respectively. In contrast, skin biopsies of the thigh and calf of the normal (left) leg both showed 100% 46,XY. Similar evidence for differences in the percentages of Y-bearing cells in the left versus right leg fibroblast cultures was obtained using densitometric scanning of dot blots following DNA hybridization with a Y-specific probe at the DYZ4 locus. Asymmetric limb growth in cases of X/XY lymphocyte mosaicism warrants further cytogenetic investigation to substantiate possible genotype-phenotype correlations which may help uncover the fundamental growth deficiency in Turner syndrome.

Adolescent↗
PubMed1991

[Non-invasive diagnosis of a right coronary artery-right ventricle fistula by Doppler echocardiography].

A six-year-old girl with an atypical continuous precordial murmur, was suspected of having a coronary arteriovenous fistula. A markedly dilated right coronary artery was revealed by two-dimensional echocardiography. The pulsed Doppler examination showed a diastolic retrograde flow in the ascending aorta, with a normal flow in the left ventricular outflow tract. With the sample volume in the right ventricle a continuous turbulent flow was observed. Color flow mapping showed a turbulent, systolic-diastolic flow in the right ventricle. The fistula was confirmed by cardiac catheterization.

Child↗
PubMed1990

[Double outlet left ventricle with pulmonary atresia].

A case of double outlet left ventricle with pulmonary atresia is reported. The hypoplasia of the left ventricule produced by the almost total absence of its trabecular zone has not been previously reported.

Heart Ventricles↗
PubMed1988

Preliminary evaluation of the use of mussel adhesive protein in experimental epikeratoplasty.

We have used a preliminary formulation of a bioadhesive in an experimental model of epikeratoplasty in rabbits. The adhesive, termed mussel adhesive protein (MAP), is a repeating decapeptide polymer that is the natural adhesive substance produced by the common blue mussel (Mytilus edulis) and is used here in conjunction with an enzymatic cross-linking agent. This study marked the first in vivo use of this material in adhering ophthalmic tissue planes. We used a simplified epikeratoplasty technique highlighted by freehand dissection of donor lenticules and host keratotomies. Approximately 10 microL of a combination of MAP and the cross-linking agent was applied directly to the host cornea and the donor lenticules were secured into the keratotomies using eight interrupted 10-0 nylon sutures. All of the sutures were removed 72 hours postoperatively. Eleven of the 15 animals retained their epikeratoplasty lenticules throughout the entire postoperative period. Four animals had initially intact lenticules that sloughed within the first postoperative week; this sloughing, we believe, was attributable to difficulties in tucking irregularly thickened lenticule edges into the keratotomy. In control animals that had lenticules secured with sutures alone, suture removal at 72 hours consistently produced immediate lenticule sloughing. Clinical examinations and histopathologic studies disclosed no untoward effects of the adhesive on the donor or host corneal tissue. We believe that this preliminary study indicates a potential adjunctive role for MAP in epikeratoplasty.

Animals↗
PubMed1987

Cavernomas of the central nervous system: clinical syndromes, CT scan diagnosis, and prognosis after surgical treatment in 25 cases.

We present our clinical experience and the results of surgical management with 25 cavernomas of the CNS, treated in our hospital in the last 10 years. The location of the lesion assessed by clinical and CT scan examinations, proved to be the most significative factor determining the prognosis of cavernomas of the CNS, after surgical removal. The symptoms started in most of the cases in the third decade of life. 19 cases were located in the cerebral hemispheres and produced three well defined clinical syndromes: Irritative syndrome (seizures) present in 70% of the cases. Space-occupying lesion syndrome (20%) and haemorrhagic syndrome (10%). The remaining six cases were located within the basal ganglia, brainstem, pineal region, cerebellum and spinal cord, showing a progressive course. CT scan studies were performed on 24 cases. The characteristic image of a cavernoma is represented by a moderately hyperdense nodule with discreet contrast uptake. Calcification was observed in and around the lesions in 33% of the cases. Perilesional hypodensities suggestive of brain tissue atrophy were noted in 22% of the CT scans. On the other hand, 12% of cerebral hemisphere cavernomas showed atypical CT scan images that suggested an erroneous diagnosis of cystic gliomas. Radical surgical removal was performed in all cases. The postoperative results varied according to the location of the lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Posterior fossa epidermoid cysts.

The authors present their clinical and surgical experience with 18 posterior fossa cholesteatomas, including three cases with atypical CT scan appearances that corresponded to calcification, haemorrhage or malignant change into an epidermoid carcinoma, respectively.

Adolescent↗
PubMed1987

Syringosubarachnoid shunt for treatment of syringomyelia.

The experiences with a series of 9 patients with syringomyelia treated by syringosubarachnoid shunt (SSS) are presented. All of the cases were evaluated by myelography, CT scan or MNR. The cases showed satisfactory results which consisted in stabilization of the symptoms (55%) or clinical improvement (44%). These results should be continuously evaluated, due to the short follow-up period and to the variable natural history of the illness. Treatment by SSS is a technique of low morbidity. It is recommended for patients with syringomyelia without significant descent of the tonsils or in those cases where posterior fossa operations have failed to obtain good results.

Adolescent↗
PubMed1987

Elevated levels of atrial natriuretic peptide during aldosterone escape.

Escape from the sodium-retaining effects of aldosterone (ALDO) is thought to occur as a result of natriuretic compensatory mechanisms triggered by extracellular fluid volume expansion. The purpose of the present study was to determine whether increases in plasma levels of atrial natriuretic peptide occur during ALDO escape in conscious dogs (n = 6) maintained on a fixed sodium intake (60 meq/day). Infusion of ALDO at a rate of 15 micrograms X kg-1 X day-1 for 6 days decreased sodium excretion (UNaV) from 59.1 +/- 4.0 to 36.2 +/- 5.7 meq/day on day 1, and then UNaV gradually returned to control levels by day 5 of ALDO infusion. Net cumulative sodium balance progressively increased during ALDO infusion, reaching a peak value of 88.8 +/- 21.3 meq/day on day 5. Mean arterial pressure increased from 85 +/- 3 to 95 +/- 4 mmHg, and plasma renin activity decreased from 1.32 +/- 0.27 to 0.32 +/- 0.07 ng angiotensin (ANG) I X ml-1 X h-1 during ALDO infusion. Plasma levels of atrial natriuretic peptide averaged 67.5 +/- 8.9 pg/ml during control and increased to a peak value of 120 +/- 18 pg/ml by day 4 of ALDO infusion. Three to four days after ALDO infusion was stopped, plasma levels of atrial natriuretic peptide averaged 46 +/- 5 and 50 +/- 6 pg/ml, respectively. In summary, escape from the sodium-retaining effects of ALDO is associated with significant increases in the circulatory levels of atrial natriuretic peptide.

Aldosterone↗
PubMed1987

[Aneurysm of the vein of Galen with neonatal cardiac insufficiency. Success of early neurosurgical treatment].

The vein of Galen malformation is a rarely recognized cause of congestive heart failure in the newborn. This report describes a newborn who developed severe cardiac failure in the second week of life. An aneurysm of the vein of Galen was noted on the computerized tomography scan, confirming the clinical diagnosis of cerebral arteriovenous fistula. The vascular abnormality was well shown by cerebral arteriography. At the age of four weeks, surgery was carried out by clipping the afferent arteries. The patient is non a three years old infant with moderate developmental delay and hypotonia.

Cerebral Veins↗
PubMed1986

Clinical and CT scan assessment of benign versus fatal spontaneous cerebellar haematomas.

We have studied 15 cases of spontaneous intracerebellar haematomas in 9 males and 6 females. A significant correlation between the clinical presentation and the CT scan features of benign and fatal haemorrhages of the cerebellum is presented. Diagnostic computerized tomographic studies were performed in a mean interval of 31 hours after the initial symptoms. 60% were diagnosed and treated in less than 24 hours; 11 patients had haematomas larger than 3 cm, and 5 (45%) of these cases died with evidence of irreversible brain-stem damage. Twelve (80%) showed compression of the fourth ventricle, 9 (60%) obliteration of the brain-stem cisterns and 8 (53%) ventricular dilatation. 8 cases were treated with surgery; 50% of them showed neurological improvement, including two cases with signs of brain-stem compression. 7 patients who were treated conservatively were followed closely with repeated CT scans, which showed that resolution of the mass effect and isodensity of the haematomas larger than 3 cm (73%), hydrocephalus (45%) and intraventricular haemorrhage (40%). Smaller haematomas without CT scan evidence of obliteration of the brain-stem cisterns or hydrocephalus had a better outcome.

Adult↗
PubMed1986

Coexpression of T- and B-markers in a lymphoproliferative disorder.

An atypical case of lymphoproliferative disorder in which T- and B-cell antigens were coexpressed in the neoplastic cells is described. The disease was characterised by hepatosplenomegaly, lymphadenopathy, a low WBC (5 X 10(9)/l) and bone marrow infiltration. The predominant cell population (greater than 70%) comprised lymphoid cells with a range of nuclear irregularities and included some blast cells. 90% of the peripheral blood lymphocytes showed a mature T-helper phenotype (E+, T11+, T3+, T4+, T8-, T6-, TdT-) with coexpression of the specific B-markers B1 and FMC7, in 90% and 50% of cells, respectively. HLA-DR antigens were present in 55% of cells while surface and cytoplasmic immunoglobulins (Ig) were detected in less than 10% of cells. Molecular investigations with appropriate probes showed evidence of T-cell receptor gene rearrangement but no rearrangement for the genes of the Ig-heavy and -light chains. Cytogenetic studies revealed a translocation t(10;19) (p12; q13) in all the metaphases analyzed. This case demonstrates that the study of neoplastic cells with a battery of monoclonal antibodies may disclose the existence of a hitherto unrecognised lymphoid cell population with atypical expression of B- and T-cell antigens. On the other hand, the presence of T-cell receptor gene rearrangement indicates that this is a T-cell disorder with the aberrant co-expression of specific B-cell markers.

Aged↗
PubMed1986

Long-term hypotensive and renal effects of atrial natriuretic peptide.

The present study was designed to examine the short-term and long-term effects of increased plasma levels of atrial natriuretic peptide on the glomerular filtration rate, sodium excretion, and arterial pressure. Intravenous infusion of synthetic atrial natriuretic peptide (2 micrograms/kg/bolus, 50 ng/kg/min continuous infusion) for 45 minutes in six conscious dogs increased plasma levels of immunoreactive atrial natriuretic peptide from 69 +/- 10 to 233 +/- 14 pg/ml. Short-term increases in plasma levels of atrial natriuretic peptide increased the glomerular filtration rate from 53 +/- 15 to 82 +/- 16 ml/min and increased sodium excretion from 74.4 +/- 32.6 to 146.9 +/- 38.1 microEq/min. Mean arterial pressure decreased slightly, from 88 +/- 3 to 83 +/- 3 mm Hg, whereas no changes occurred in plasma renin activity (2.0 +/- 0.6 to 1.6 +/- 0.8 ng of angiotensin I per milliliter per hour) or plasma aldosterone concentration (6.9 +/- 2.3 to 8.1 +/- 3.9 ng/dl). To determine whether the short-term effects of atrial natriuretic peptide on the glomerular filtration rate and sodium excretion lead to a sustained reduction in mean arterial pressure, atrial natriuretic peptide (50 ng/kg/min) was infused intravenously for 5 days in six conscious dogs. Long-term infusion increased plasma levels of immunoreactive atrial natriuretic peptide from 27 +/- 5 to 292 +/- 31 pg/ml. The infusion caused only a transient increase in sodium excretion and had no significant long-term effect on the glomerular filtration rate. Mean arterial pressure decreased from 90 +/- 3 to 74 +/- 3 and 75 +/- 4 mm Hg by Days 4 and 5 of the infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1986

Choroid plexus papilloma with chondroma: case report.

The authors report the successful total removal of a rare intracranial tumor in the right lateral ventricle of a 15-year-old girl with epileptic seizures. Histopathological examination showed a benign tumor formed by mature cartilage and choroid plexus papilloma. From our review of the literature, a mixed tumor with these histological features has not been reported previously in this location. The diagnosis, surgical approach, etiology, and prognosis of this lesion are discussed.

Adolescent↗