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Biomedical subjects

M A Ros

Publications and source records attributed to M A Ros.

47 records · Page 3Linked to original sources
PubMed1989

Should patients with normal cranial CT scans following minor head injury be hospitalized for observation?

The purpose of this study was to determine the incidence of complications in hospitalized patients with normal cranial computed tomographic (CT) scans following minor head injury (Glasgow Coma scale of 13-15). Seventy-three patients were included in the analysis, with 63 children being assigned a GCS score of 15 at presentation. Seventy-one percent of patients were male, and motor vehicle accidents accounted for 56% of the injuries. Forty patients reported loss of consciousness (LOC) following the accident. The mean length of hospital stay was 1.69 +/- 0.94 days. GCS scores, history of LOC, vomiting, or seizures did not significantly influence length of hospitalization. None of the patients developed complications, and all were discharged in good condition. We conclude that a child with minor head injury, GCS score of 15, and a normal neurologic examination and cranial CT scan can be safely discharged to the care of a responsible adult and can be observed at home.

Adolescent↗
PubMed1989

A technique for fluorescence microscopy in semithin sections.

We describe here a procedure to improve contrast and resolution in fluorescence microscopy of sectioned tissues. Tissue fragments were fixed in ethanol-glacial acetic acid, embedded in diethylene glycol distearate, and semithin sectioned. This method maintains tissue antigenicity while preserving the structure of cells and tissues. The thinness of the sections eliminates scattered and emitted light from tissue structures outside the plane of focus. The procedure is simple and quick, and works excellently with fluorescein-conjugated lectins and antibodies.

Animals↗
PubMed1989

Branch retinal-artery obstruction: a review of 201 eyes.

A study of 187 patients (201 eyes) with branch retinal-artery occlusion (BRAO) was done to determine the etiology, natural history, and treatment of this disorder. On follow-up, almost 90% of the patients had visual acuity of 20/40 or better. The rest had poor visual acuities initially. The patient population was divided into three groups according to treatment. Group I included 65 patients treated aggressively with mechanical and pharmaceutic measures to reduce intraocular pressure and with anti-platelet drugs. Group II was composed of 81 patients treated only with antiplatelet agents given chronically. Group III (41 patients) received no treatment and represented the control group. No statistically significant difference in visual outcome was found on comparison of these three groups of patients. In this study we observed that 98% of the BRAO cases involved the temporal arteries. Emboli were documented in 125 eyes (62%). Systemic hypertension was common (132 patients or 71%). Although BRAO appears to be a relatively benign disease, its association with severe systemic conditions and documented increase in patient mortality suggests the need for careful evaluation by ophthalmologists.

Adolescent↗
PubMed1988

Spatial and temporal changes in the pattern of glycosylation of the developing chick limb tissue components as revealed by fluorescent conjugated lectin probes.

The changing pattern of expression of glycoconjugates during the differentiation of the chick leg bud between stages 17 to 34 (days 3 to 8 of incubation) was studied using fluorochrome-labelled plant lectins. Limb buds were fixed in cold acetic-alcohol and wax-embedded. Agglutinins of peanut (PNA), soybean (SBA) and succinylated wheat germ (WGAs) revealed a specific binding pattern in the apical ectodermal ridge (AER) between Hamburger and Hamilton stages 19-32. These stages coincide with the period of elevation of the AER. This specific binding pattern was absent from the adjacent dorsal and ventral ectoderm. Prechondrogenic cells were positive for WGA and for PNA, and the PNA-binding capacity was intensified after neuraminidase treatment. Premyogenic cells at stage 23 can be identified as negative to PNA after neuraminidase, while the blood vessels became positive. PNA, SBA, WGA, WGAs and, in addition, Ricinus communis (RCA-I) lectins stained the basal membrane. Strands of extracellular matrix which connect with the basal membrane and cross the limb transversely between dorsal and ventral ectoderm were stained by RCA-I, SBA and PNA after neuraminidase.

Animals↗
PubMed1987

Ocular ischemic syndrome: long-term ocular complications.

Acute retinal arterial occlusive events in the eye are generally easily recognized and the association with embolic material, often from ulcerative lesion of the ipsilateral carotid vessels, usually can be established by noninvasive imaging techniques. In contrast, chronic retinal and choroidal circulatory impairments from ophthalmic artery insufficiency is usually due to high-grade, hemodynamically-significant carotid occlusive disease which can be difficult to recognize because of the diverse clinical features and presentations. We present herein the experience of the senior author (LEM) in the diagnosis and management of these complex cases.

Aged↗
PubMed1986

Evidence for a new type of juxtamedullary nephron in the rabbit kidney.

The microanatomy of a unique type of juxtamedullary nephrons has been studied in the rabbit kidney by means of corrosion casts, scanning electron microscopy and the air cast method. The nephrons described in this paper are located in the outer stripe of the outer medulla and are the only nephrons that are not arranged radially within the kidney. They differ from other juxtamedullary nephrons in the morphology and course followed by the proximal tubule and by the close relationship that they establish with the arcuate vessels. The glomerulus of these nephrons is supplied by a short afferent arteriole that arises directly from the arcuate artery. Because of the special characteristics of these nephrons we have named them 'arcuate nephrons'. The morphology, spatial relationships and vascularization of the arcuate nephrons suggest that these nephrons differ functionally from the other juxtamedullary nephrons. Possible developmental factors responsible for the special microanatomy of the arcuate nephrons are analyzed.

Animals↗
PubMed1986

Polycystic kidney disease induced by corticoids. A quantitative and qualitative analysis of cell populations in the tubular cysts.

The sequential changes of cell morphology and the ratio distribution of the different types of cells which exist in tubular cysts induced by methylprednisolone acetate have been studied by light, transmission and scanning electron microscopy. We have also studied the blood levels of sodium and potassium by flame photometry. In both control and cystic ducts, at the level of the outer cortex, the first intercalated cells (IC) were not observed until the 4th postnatal day. Some intermediate cell configurations were observed during the 3rd postnatal day, suggesting that some primitive principal cells (PC) are transformed into IC. Development of IC seems to be independent of both the effects of corticoids and the blood levels of potassium. The ratio distribution and the types of IC observed throughout the period studied was similar in both normal and cystic ducts. The type of IC characterized by the presence of a huge apical process, which has gone previously undescribed with either TEM or SEM, was observed in both control and cystic ducts. We propose to name these cells as cells with surface pattern type V. During the period of regression of the tubular cysts dead and migrating cells were observed closely associated with cilia of the PC. Both types of cells do not seem to represent, based in their localization and frequency, abnormal cell types of the cyst wall. Our results support the hypothesis that renal cysts are giant collecting ducts which conserve both the morphology and the function of the epithelium.

Adrenal Cortex Hormones↗
PubMed1985

Vascular architecture modifications in the steroid-induced polycystic kidney.

This paper presents a study of the renal vascular architecture in polycystic kidneys induced in newborn rabbits by a single injection of methylprednisolone acetate. Ink perfusion and polyester resin corrosion casts were utilized, and the vasculature was studied by light and scanning electron microscopy. Vascular alterations were observed in the two main evolutive stages of the renal polycystosis: the stage of tubular cysts and the stage of glomerular cysts. These alterations were compared with the normal vascular pattern of control kidneys. At the tubular cyst stage the sinusoidal vascular cortical plexus persisted for a long period of time and the superficial cortical glomerular tufts were poorly developed. At the glomerular cyst stage, the vascular architecture of the superficial cortex showed numerous alterations. The glomerular tufts were small and their structural pattern was affected. Frequently the hilum was very wide and the afferent and efferent arterioles were on opposite sides of the glomerular tufts. The afferent arterioles were variable in size and length. Sometimes the glomeruli showed several afferent arterioles. There were numerous cases of double efferent arterioles in the superficial glomeruli of the polycystic kidneys. Various types of aglomerular shunts were observed regardless of the cystic stage or age. These data indicate that, in addition to the cysts, the corticoid-induced polycystic kidneys showed alterations of the renal vascular architecture which are interpreted as a malformation. We suggest, on the basis of these morphologic observations, that the pathogenesis of the polycystic kidneys is not related to the vascular alterations.

Animals↗
PubMed1984

A new and simple method for studying the microanatomy of nephrons and collecting tubules.

A simple procedure for studying the microanatomy of the kidney by light microscopy is described. Specimens are dried by the critical-point method and later impregnated with a mounting medium. The retention of air within the lumen of nephrons and collecting tubules permits their visualization. The method allows the observation of renal microanatomy without the distortions produced by microdissection or the loss of structural relationships among different kidney components. It also permits observation of the same specimen by both light and scanning electron microscopy.

Air↗