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Biomedical subjects

G Martinez

Publications and source records attributed to G Martinez.

At least 91 records · Page 5Linked to original sources
PubMed1994

Results from a reference laboratory for prenatal diagnosis of sickle cell disorders in Cuba.

A nationwide programme for the prevention of sickle cell (SS and SC) disorders was initiated in Cuba in 1983. Couples at risk were identified by screening pregnant women and the partners of those who carry an abnormal haemoglobin, followed by genetic counselling and the offer of prenatal diagnosis. Prenatal diagnosis was performed in one laboratory, which had carried out 1068 prenatal tests for Hb SS and SC disorders by the end of 1992. The centralization of the service has permitted rapid identification and resolution of problems.

Amniocentesis↗
PubMed1994

An eye-movement analysis of the effects of scotopic sensitivity correction on parsing and comprehension.

Does scotopic sensitivity correction enhance parsing and, thus, comprehension? Twenty-two readers with scotopic sensitivity (mean age = 20.3 yrs.; 40.9% male) parsed sentences under scotopic correction and control conditions. Measures included eye-movement indices of parsing and comprehension questions. Although eye movements suggested enhanced parsing, comprehension scores were not significantly improved with correction.

Adolescent↗
PubMed1994

Hypertension and electrolyte therapy.

Approximately 50 million Americans are at risk for cardiovascular and cerebrovascular disease as a result of hypertension (HTN). Education and treatment programs aimed at reducing HTN have been successful in decreasing morbidity and mortality from heart disease and strokes in recent years. In addition to pharmacologic means, prevention of HTN by lifestyle modifications has become a focus of public health education. One such modification, electrolyte therapy, has been associated with HTN control and is readily available through both dietary sources and supplementary tablets. This article presents an overview of electrolyte therapy as treatment for HTN, and reviews studies of the effects of sodium, potassium, and magnesium, and their combinations as treatment to reduce blood pressure. Strategies for nurses in educating the public on the effects of electrolytes and blood pressure are also discussed.

Blood Pressure↗
PubMed1993

p53 gene rearrangements in chronic myelocytic leukemia.

We performed Southern-blot analysis of the p53 gene in 41 consecutive patients with typical chronic myelocytic leukemia (CML). In two of them, we were able to study cells during both the chronic and the accelerated phases. Only one of the 29 chronic-phase samples had rearrangement of the p53 gene, whereas three of the nine accelerated-phase samples and one of the five patients in blast crisis exhibited rearrangements. Gene deletion was observed in two patients, one in accelerated phase and the other in blast crisis. One patient with a nonrearranged p53 gene in chronic phase showed rearrangement after progression to the accelerated phase. On the other hand, one patient in accelerated phase exhibited rearrangements which disappeared after reversion to chronic phase with successful treatment. Our findings support the opinion that alterations of the p53 gene may play an important role in CML evolution.

Blast Crisis↗
PubMed1993

Mutagenic activity of urban air samples and its modulation by chili extracts.

Different samples of ambient particulate organic matter were collected during the summer and winter of 1990 in Mexico City. After dichloromethane extraction, the samples were tested for mutagenicity with derivatives of Salmonella typhimurium possessing high activity of 'classical' nitroreductase (YG1021) or O-acetyltransferase (YG1024), and compared to the mutagenicity of the normal strain YG1020, and to that of a nitroreductase-deficient mutant TA98NR. The two enzyme-overproducing strains were more sensitive to the mutagenic effect of the extracts than the parent and deficient strains. The sensitivity order, i.e., YG1024 > YG1021 > YG1020 > TA98NR, emphasizes the usefulness of the new Salmonella strains in analyzing the mutagenicity of complex mixtures and suggests that some of the direct mutagenic compounds in the urban air samples are nitro-aromatics. Investigations were also conducted to analyze the effect of chili extract on the mutagenicity of an urban air sample. The extract itself showed moderate mutagenic activity and an additive effect was noted when both the chili and air extracts were present. On the other hand, the maximum volume of chili tested produced a decrease in the number of revertants without affecting the background lawn of bacterial growth. The same response was also observed when 1-nitropyrene, 1,6-dinitropyrene or 1,8-dinitropyrene was used as the genotoxic compound, although potentiation instead of addition occurred at low vegetable volumes. At the concentrations found in the chili extract, chlorophyllin and beta-carotene showed an antimutagenic effect against the nitro-aromatic compounds.

Air Pollution↗
PubMed1991

The vasculature of the rat penis: a scanning electron microscopic and histologic study.

As a basis for understanding the mechanism of erection in an animal model frequently used in research in reproductive biology, the angioarchitecture of the penis of the rat has been described using scanning electron microscopy. Study of the penile vasculature of the rat indicates that the corpora cavernosa penis and the corpus spongiosum are independent erectile tissues, each with its own arterial and venous vessels. The large vascular spaces and abundant smooth muscle of the penile crura are compatible with its role in regulating blood flow to more distal penile tissues. Helicine arteries of the crura, but not the parent deep penile artery or arteries elsewhere, have muscular cushions in their walls. The venous drainage of the penile crura is via subtunical veins which are thought to be compressed during erection to elevate pressure within the penis. Large, paired cavernous veins drain the shaft of the penis. A unique method for inhibiting blood flow from the penis is indicated by the division of the cavernous veins into smaller channels prior to joining the subtunical venous plexus. Erectile tissue in the bifid origins of the corpus spongiosum has abundant cavernous muscle, while in the remainder of the corpus spongiosum little smooth muscle lines the cavernous spaces. The cavernous spaces on either side of the urethra coalesce to form vessels, each of which communicates with cavernous spaces in the glans. In addition, a bypass of the glans is effected by communication of these vessels directly with the deep dorsal vein. The apparent absence of muscular pads in vessels of the spongiosum, the relative paucity of cavernous smooth muscle, and the ample venous drainage provided by the deep dorsal vein may account for the lack of a venous occlusive mechanism similar to that of the corpora cavernosa penis.

Animals↗
PubMed1991

High doses of recombinant alpha-interferon or gamma-interferon for chronic hepatitis C: a randomized, controlled trial.

Chronic hepatitis C is often a progressive liver disease for which there is no satisfactory treatment. We studied the efficacy of recombinant alpha-interferon or gamma-interferon in the treatment of this disease in comparison with a control group. Thirty patients were randomly assigned to three groups. Ten patients received 7.5 MU alpha-interferon/m2 body surface three times weekly for 3 mo, then 5 MU/m2 for 3 mo and 2.5 MU/m2 for 6 mo. Ten patients were treated with gamma-interferon at a dose of 2 MU/m2 for 6 mo and the other 10 served as controls without treatment. The mean serum ALT levels and liver histological findings improved significantly only in the patients treated with alpha-interferon. No changes were observed in patients treated with gamma-interferon or in controls. Five of 10 patients treated with alpha-interferon had complete responses (mean ALT normal during therapy). After treatment ALT returned to pretreatment levels in two of 5 patients. The long-term response rate after alpha-interferon therapy was 30% at 18 mo. We conclude that alpha-interferon is effective in controlling disease activity in a portion of patients with chronic hepatitis C. High doses of alpha-interferon do not appear to add further benefit in the response rate or relapse rate. gamma-Interferon therapy is ineffective.

Adult↗
PubMed1991

Further evidence for the molecular heterogeneity of chronic myeloid leukemia.

Cytogenetic and molecular techniques were performed on samples obtained from 29 patients with chronic myelocytic leukemia (CML); 27 were in the chronic phase and two were in blast crisis. A further five cases were also analyzed, two with atypical CML (aCML), one with chronic neutrophilic leukemia (CNL), and two with juvenile CML (JCML). Most of the cases with typical CML were Philadelphia chromosome (Ph) positive and had a rearrangement within the major breakpoint cluster region (M-bcr). One of these cases was shown to be Ph positive but showed no rearrangement within the M-bcr. Two cases with clinical features typical of CML were Ph negative. One of these showed a rearrangement within the M-bcr, but no rearrangement was demonstrated in the other. Both patients in blast crisis were Ph positive and M-bcr positive. One showed a second Ph. Patients with aCML were Ph negative and had no M-bcr rearrangement. A polymorphism within the M-bcr was found with BglII in one case. No Ph chromosome or M-bcr rearrangement was found in CNL or JCML. These data support the molecular heterogeneity reported in CML.

Blast Crisis↗
PubMed1991

[A histological study of the meniscal insertion of the external pterygoid muscle].

The paper reports a study of the relationship between the upper head of the pterygoid muscle and the temporomandibular joint disc. Using optical microscopy, TMJ serial sections of 10 human embryos and fetuses aged from 6 to 22 weeks were examined. From the observation of serial sections, it appears that from the start of histogenesis the lateral pterygoid muscle is in contact with the condylar blastema and later with the disc and the condyle. A fibrous attachment was detected between the muscle tendon and the meniscus, and oxytalan and elastic fibres were observed near this attachment.

Gestational Age↗