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Biomedical subjects

M Herrera

Publications and source records attributed to M Herrera.

At least 127 records · Page 7Linked to original sources
PubMed1984

Cerebral computed tomography in maple syrup urine disease.

Maple syrup urine disease (MSUD) is an inherited metabolic disorder due to decreased decarboxylation of branched chain keto acids triggering an accumulation of leucine, isoleucine, and valine. We describe two infants with biochemically confirmed MSUD in whom computed tomography (CT) revealed cerebral edema. In one of these cases repeat CT 40 days after institution of appropriate therapy revealed that the edema had disappeared and the ventricles had enlarged.

Brain Edema↗
PubMed1984

The commissural neurons of the inferior colliculus of the rat.

During systematic observation of the cellular subnuclei of the inferior colliculus of adult rats, it was noted that in the zone of the intercollicular commissure, numerous neuronal perikaria appear intermingled between the commissural fibers. The neurons were studied using Golgi and TEM methods and classified according to their dendritic pattern in the isodendritic (15%), allodendritic (19%) and intermediate forms (66%) of neurons. A fourth neuronal group, situated between the commissure and the upper periventricular zone, is also in relation with the commissural fibers. The constancy of these neurons and their frequently axodendritic and axosomatic synapses suggest that they play an important role in the whole function of the commissure which, at present, is not well understood in spite of the number and distinct origin of their afferents.

Animals↗
PubMed1984

Experimental contribution to the origin of brain-stem potentials.

The origin of the different BSP waves is open to discussion. In this work we analyze the response curves with surface and intranuclear electrodes in cats, both before and after inducing electrolytic lesions in acute and chronic phase, in order to study the subsequent alterations. We found that waves whose origins are attributed to specific regions of the acoustic pathway when carried out with surface electrodes, fail to correspond with the results obtained by intranuclear electrodes. On the other hand, although the lesions to the lowest part of the acoustic pathway (cochlear nuclei) cause important alterations in the recordings, these alterations become smaller as the lesions are induced higher up the pathway. Thus, we believe that the origin of the different BSP waves is due to the sum of potentials of different zones of neuron activation, and not to specific locations of the acoustic pathway; this is more evident in the delayed waves.

Animals↗
PubMed1983

Percutaneous techniques in the management of urological complications in renal transplant patients.

Obstruction of urine flow and urine leaks are potentially life-threatening complications in renal transplant patients. The diagnosis is difficult, and definite treatment may therefore be delayed. This paper reviews the clinical course of ten renal transplant patients with urologic complications, discusses the limitations of the standard tests used to investigate such problems, and describes the role of percutaneous antegrade pyelography and nephrostomy drainage catheter placement as safe and accurate diagnostic and therapeutic procedures.

Adolescent↗
PubMed1983

[Nutritional impact of supplemented food in relation to the duration and severity of infectious episodes].

The nutritional impact of three different programs of supplementary feeding implemented with children aged 6-24 months, was examined in relation to the duration and the severity of infectious diseases. After a 2-month intervention, statistically significant changes in weight for length were found in two of the groups (those supplemented with rice and beans, and those supplemented with rice cereal enriched with oil). No significant changes in weight for length were found in the other groups (those supplemented with banana cereal and the control group), nor were statistically significant changes found in any of the four groups in relation to weight for age, nor length for age. No statistically significant changes were found on the incidence, duration, and severity of infectious diseases. As a result of these findings it can be postulated that despite a high frequency of infectious episodes, often severe and of long duration, supplementary feeding on the early part of life can be effective when there is a high risk of malnutrition.

Anthropometry↗
PubMed1983

[Juvenile malignant osteopetrosis. Clinico-radiological study of 7 cases].

Clinical and radiological studies of seven patients with autosomic recessive malignant osteopetrosis are presented. Diagnosis was established before the age of 3 months in six cases and at 7 months in one. In all cases the presenting signs were pallor and hepatosplenomegaly with associated neurological involvement in five. All patients had normocytic normochromic anemia, leucopenia and thrombocytopenia with features of extramedullary hematopoiesis. Radiological studies revealed increase in the density of bones with "mask" appearance of facial bones and diminished size of optic foramina. Long bones showed absence of normal trabeculae and anomalies in modeling with methaphiseal bands and "bone within bone" images. There was hypocalcemia and hypophosphatemia with slight increases in alkaline phosphatase; parathormone was normal. Clinical course was characterized by progressive pancytopenia, recurrent infections and neurological deterioration with convulsions, nistagmus and optic atrophy. Five out of the seven patients died after a median of 3 months, due to infections or haemorrhage. The patient diagnosed at 7 months of age presented bilateral optic atrophy and moderate anemia; no other complications appeared after 2 year follow-up. Histological findings included substitution of bone marrow by chondro-osseous tissue; focal obsteoblastic and osteoclastic activity in calcified cartilage, and myeloid metaplasia in liver, spleen, lymph nodes and kidneys. The lesions are in agreement with the concept of a defect in bone formation-resorbtion balance; dysfunction of both osteoclasts and osteocytes is implicated in the pathogenesis. Unlike experimental disease, osteopetrosis in man is probably an heterogeneous disease and appropriate therapy should be individualized. Nevertheless, at present, the only favorable results have been obtained with bone-marrow transplantation.

Female↗
PubMed1982

Periventricular calcifications in a newborn associated with aneurysm of the great vein of Galen.

A newborn infant who presented with heart failure was diagnosed to have an aneurysm of the vein of Galen. Skull radiographs and CT scan demonstrated multiple periventricular calcifications. This case illustrates a new diagnostic possibility for the radiologic finding of periventricular calcifications in the newborn. It also establishes the importance of performing good skull roentgenographic series in all neonates with unexplained heart failure.

Calcinosis↗
PubMed1982

Coilon removal.

Explore the source record for details and available documents.

Adult↗
PubMed1982

The significance of efficient scatter removal in chest radiography.

The conventional approach to the removal of secondary radiation in chest radiography is by using an air gap or a radiographic grid. However, grids become ineffective at high kVp levels. This study evaluated efficient scatter removal by radiographic scanography versus the conventional technique. Nylon spheres simulating lung nodules were attached to a standard radiographic thorax phantom and to a special chest phantom of our own design. Conventional and scanographic films were made of the phantoms using the same conditions. The films were read in a double-blind fashion. The results indicated that scanograms permitted appreciation of the simulated nodules over the lungs better than did the conventional films, particularly at higher kVp levels. However, the marked increase of contrast resulted in an underpenetration of the mediastinum. If properly penetrated, the lung fields were overexposed, which resulted in a decrease of the detectability of lesions in spite of a higher normalized contrast. Scanography is a promising technique for improving the detection rate of lung nodules on chest films, provided that means can be found to penetrate the mediastinum without overexposing the lungs.

Humans↗
PubMed1982

Transluminal dilatation of coarctation of the abdominal aorta. An experimental study in dogs.

The optimal treatment for recurrent coarctation of the aorta remains undefined. Recurrent stenosis following surgical repair occurs in 6-48% of cases involving the thoracic aorta. Because of the high morbidity and mortality associated with surgery, an alternate approach such as transluminal angioplasty is desirable. To evaluate this possibility, the authors created several experimental lesions to test their capability for dilatation, using the percutaneous transluminal technique. The results indicate that balloon dilatation of coarctation after end-to-end anastomosis is difficult or impossible. Dilatation of other types of suture lines may also be difficult due to the large amount of fibrous tissue at the anastomotic site, which is not amenable to balloon dilatation. Thus surgery remains the preferred form of therapy.

Angioplasty, Balloon↗
PubMed1982

Ivalon shavings: technical considerations of a new embolic agent.

Ivalon (polyvinyl alcohol sponge) shavings can be used as a permanent embolic material. When injected as a suspension with assorted particles of proper size, congenital arteriovenous malformations can be cured, eliminating the need for surgical excision.

Adolescent↗