Biomedical subjects
Publications and source records attributed to G Marin.
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The CT findings in 37 asphyctic newborns are presented, particularly concerning the hypodense lesions. 11 out of 27 term infants and 4 out of 10 preterm neonates had 2 or 3 serial scans, the last when they were 2-5 months old. In most of cases a long run normalization of former periventricular hypodensity has been observed, with normal clinical follow-up, 6 cases (2 preterm and 4 term neonates) had cortical hypodensity too: 2 of these revealed afterwards atrophy and hydrocephalus, 2 ventricular asymmetry and slight cortical spaces enlargement; in 1 case the cortical parietal hypodensity, formerly showed, was confirmed; 1 case finally was normal at three month scan. The relevance of the cortical hypodensity in most serious brain damage is underlined; the hypodensity of the white matter, on the contrary, could mean wether a postasphyctic lighter, reversible brain damage, or the physiologic postnatal condition, such a still unfilled myelinization.
Triparental crosses were carried out between Chinese hamster and mouse cell lines, by using combinations of recessive and dominant markers. Evidence is provided that triparental somatic hybrids arose at relatively high frequencies in triselective media, after fusing with polyethylene glycol mixtures of three cell types carrying the appropriate resistance markers. The Karyotypes of these hybrids were consistent with their triparental origin. Since triparental chromosome complements were observed also in some of the cells selected for two markers only, the possibility is discussed that nuclear multiplicities higher than two in fused cells may favor, rather than hinder, viable hybrid formation.
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We have determined the effect of parental cell concentration at the time of fusion with polyethylene glycol on the frequency of viable somatic hybrids and of polykaryocytes of different multiplicity, between Chinese hamster (line Wg3) and mouse (line 3TP) fibroblasts. Fusion appeared to be dictated by the random encounter of cells only at low cell concentrations. However, no evidence for species-specific restriction of fusion was obtained at any cell concentration.
The first two cases of rhinoentomophthoromycosis to be recognized in Costa Rica are reported. The first patient was a 32-year-old Caucasian male from the Pacific Coast, and the second, a 17-year-old Negro male from the Atlantic Coast. Both cases showed the typical involvement of the nasofacial skin with the formation of subcutaneous nodules. One patient also showed left maxillary sinus involvement. Both patients were in general good health, without any associated disease. Cultures from the second patient, taken from the glabellar nodule, were positive for Conidiobolus coronatus. These two cases represent the first documentation of this uncommon mycosis in Central America.
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We describe a syndrome identified in three consanguineous families who had two and probably four common ancestors five generations ago. The syndrome is characterized by profound dysfunction of the central nervous system, silver-leaden colored hair, abnormal melanosomes and melanocytes, and abnormal inclusion bodies in fibroblasts, bone marrow histiocytes and lymphocytes which appear to represent abnormal lysosomal bodies. Because of the biochemical relationships between melanin-melanosomes and neuromelanin, we think that all the manifestations of the condition are related to and represent pleiotropic effects of a newly identified gene in man in its homozygous state. Biochemical reactions of the cells of these patients indicate presence of tyrosinase in the melanosomes.and show that the substance accumulated in cultured fibroblasts and in the bone marrow histiocytes is a PAS and Oil-red-O positive material but is Oil-red-O negative after extraction; it has the typical reactions of melanin withe the Masson and Fontana stain, but cannot be considered typical melanin, since without stain it is colorless. The ultrastructural studies showed round granules with variable matrix, similar in fibroblast and bone marrow, and with variable intensity of reaction to osmium. This mutation principally affects the neuroectoderm, but also the mesoderm.
A retrospective appraisal of traditional neuroradiological techniques (such as direct röntgenograms, cerebral angiography RISA-cisternography, and pneumo-cisterno-encephalography, as opposed to the "new" technique of computer-assisted tomography) was carried out in a series of 82 cases of opto-chiasmatic arachnoiditis, all surgically verified. It is concluded that none of these examinations can provide a reliable diagnosis of opto-chiasmatic arachnoiditis, which preoperatively can only be a tentative diagnosis that becomes final only when confirmed by surgical findings. In the presence of certain progressive neuro-ophthalmological symptoms and signs, a negative neuro-radiological investigation should not deter the neurosurgeon from exploring the chiasmatic region. Computer-assisted tomography, of which the authors have no personal experience in these cases, may hold the future answer to the diagnostic problem.
Three cases of an infrequent cerebral vascular malformation, venous angioma, are reported. The first 2 of these cases, with the lesion in a supratentorial location, exhibited exophthalmos as a presenting symptom, together with palpebral or intraobital angiomatous formations, and also impairment of visual function. The first patient was operated upon and the "venous angioma" could be confirmed histologically. An angiographic follow-up of the same patient at an 18 year interval was also possible. The diagnostic work-up to be performed in cases of exophthalmos is discussed and the need for angiography is stressed.
The report pertains to some data on the cholinesterase activity in the blood serum and CSF of 62 patients with epilepsy, in correlation with different clinical characteristics (the severity of the disease, the character of the EEG, frequency of seizures, treatment efficacy, etc). In 86,8% of the cases there was a significant increase in the activity of serum cholinesterase. Increased cholinesterase activity correlated only with pronounced pathological changes in the EEG (reverse correlation) and the efficacy of treatment (direct correlation). After surgical treatment of 9 cases there was a drop in the cholinesterase activity of the blood serum and CSF, which correlated with an improvement in the general state of the patients. On the basis of personal experience, as well as literary data, it is assumed that an increase in the cholinesterase activity in epileptic patients is not related to the main etiological factors of this disease but is rather a secondary change, a peculiar "symptom" of the disease.
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Adhesive arachnoiditis is an occasional finding during neurosurgical operations for pituitary adenoma, previously treated by radiation therapy. A case where an arachnoidal process was found in combination with an eosinophilic pituitary adenoma, which had never been treated by irradiation, is reported. A 44-year-old woman at the time of surgery with scarce endocrinologic symptoms had suffered visual loss from 2 episodes, 18 years apart. Analysis of her symptoms, neuro-ophthalmologic findings and neurodadiologic features suggest that her visual damage was due to an optochiasmatic arachnoiditis, rather than to the tumor itself.