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Biomedical subjects

M E Vega

Publications and source records attributed to M E Vega.

13 recordsLinked to original sources
PubMed2006

Osteoprotegerin and bone mass in squamous cell head and neck cancer patients.

Osteoprotegerin (OPG) is considered one of the main regulators of bone remodeling. Various patterns of serum OPG levels have been described in different types of tumors. We undertook this study to determine serum OPG levels in patients with squamous cell head and neck cancer (SCHNC), analyzing their relationship with other metabolic bone parameters and bone mineral density (BMD), as well as the possible influence of chemotherapy. Forty male patients with localized SCHNC were studied, and their results were compared with those of 40 healthy male controls. The type of treatment followed by each patient was noted. Age, weight, height, and lifestyle habits were recorded; and OPG, Ca(2+), intact parathyroid hormone (iPTH), 25-Hydroxyvitamin D (25OHD) and 1,25-Dihydroxyvitamin D (1,25(OH)(2)D), bone alkaline phosphatase, osteocalcin, and serum C-terminal cross-links telopeptide of type I collagen (ICTP) were determined. Dual-energy X-ray absorptiometry BMD at the lumbar spine, femoral neck, and hip was also measured. Serum OPG was higher in patients than in controls (91.7 +/- 25.8 vs. 77.2 +/- 26.3, P = 0.02). ICTP (a bone resorption marker) was 37% higher in patients (P = 0.007). Bone mass was lower in patients at the lumbar spine, femoral neck, and total hip. Lumbar spine Z-score showed a significant progressive decrease in controls, stage I-III patients, and stage IV patients. Logistic regression analysis showed a significant association between the disease and serum OPG levels, the odds ratio per standard deviation increase of this being 1.9 (95% confidence interval 1.1-3.8, P = 0.04) after adjusting for bone mass and ICTP serum levels, as well as for alcohol and smoking history. Adjustment for alcohol intake and tobacco use did not cancel out BMD differences between patients and controls. Patients with SCHNC show increased OPG serum levels, increased bone resorption, and decreased bone mass. The OPG rise appears to be unrelated to the BMD decrease, and the BMD decrease seems to be, at least in part, independent of smoking and drinking habits. No differences in either OPG or BMD were seen between patients with and without chemotherapy. Further studies are needed to clarify the mechanisms responsible for OPG and BMD changes in SCHNC.

Aged↗
PubMed2001

Characterization of HIV isolates from Puerto Rican maternal-infant pairs reveal predominance of non-syncytium inducing (NSI) variants with CCR5 genotype.

In this study, HIV-1 variants from a cohort of forty-eight Puerto Rican pregnant women and their 50 infants (one had triplets), were isolated and characterized, in order to determine the type of HIV-1 variants that are predominantly transmitted. All were enrolled in the prenatal AIDS Clinical Trials Group (ACTG) and received anti-retroviral therapy. Fifteen of the 50 infants (30%) were positive by V3 PCR suggesting that they harbored a copy of the HIV envelope gene. Three of 50 infants (6%) were HIV-1 culture and PCR positive, indicating active infection. HIV-positive cultures were obtained from 32 of the 48 mothers. Sixty two percent of the isolates (20/32) were macrophage-tropic and non-syncytium inducing, three percent (1/32) had dual tropism, and thirty four percent (11/32) were non-syncytium inducing and did not grow in macrophages. Phenotype and genotype of the HIV variants from the three infected infants revealed the presence of macrophage-tropic and non-syncytium-inducing strains. Genotype analysis of the HIV env V3 loop revealed the presence of specific amino acids that are predictive of CCR5 usage. Sequence analysis of the HIV pol gene from the three infected infants indicated that vertical transmission was not caused by the presence of antiviral resistance mutations. These results indicate that mothers undergoing antiretroviral treatment at different stages of the disease and with different viral loads transmit predominantly macrophage-tropic/non-syncytium inducing/CCR5 variants to their infants.

Adolescent↗
PubMed1997

Longitudinal studies on maternal HIV-1 variants by biological phenotyping, sequence analysis and viral load.

In this study, the HIV-1 variant viruses from ten pregnant women and their infants were isolated and characterized longitudinally in order to determine the role that viral envelope (gp120-V3 loop) gene variation and viral tropism play in vertical transmission. Biological phenotyping of each HIV variant was accomplished by growth in MT-2, and macrophages from healthy and non-HIV-infected donors. Genetic characterization of the variants was accomplished by DNA sequence analysis. All the women enrolled in this study received ZDV therapy. Virus was cultured from eight out of ten env V3-PCR positive mothers. HIV-1 isolates were all non-syncitium inducing variants. None of the mothers were found to transmit HIV, as determined by DNA PCR and quantitative co-cultures on their infants which were seronegative for HIV-1 through one year after birth. Viral cultures from infant blood samples were negative and infants were all healthy. However, nested env V3-PCR detected proviral DNA in five out of ten infants. In contrast, conventional gag-PCR was negative in the same five infants. Sequences of the five maternal-infant pairs were different, suggesting unique infant HIV-1 variants. The three highest maternal viral load values corresponded to infants that were env V3-PCR positive. These results suggest that HIV-1 particles are transmitted from ZDV-treated mothers to infants. Infant follow up is recommended to determine if HIV-1 has been inhibited by the immune system of the infants.

Adult↗
PubMed1990

The amputation level: noninvasive methods and clinical criteria.

Before undergoing amputation of a lower limb, one hundred and forty-six patients suffering from arteriosclerosis were studied with the purpose of finding prognostic indicators of success at the most distal level. The best results were obtained when skin perfusion pressure was above 60 mmHg in diabetics and above 40 mmHg in non-diabetics. Lower limb systolic blood pressure and skin thermometry also proved to be useful. The method proposed might be helpful to the surgeon in choosing the best treatment for the patient. It is a nonivasive procedure which can be easily performed and does not require sophisticated or expensive equipment.

Amputation, Surgical↗
PubMed1988

Hemodynamic characteristic of the common carotid arteries in diabetic atherosclerotic patients.

Early detection of stenosis is an important task in noninvasive examinations. The authors analyzed 50 patients with diabetic macroangiopathy in lower limbs, but without signs, or symptoms of brain ischemia, and 50 supposedly healthy subjects of similar sex and age composition as control. Eight hemodynamic parameters were measured in the common carotid artery using Doppler ultrasound with spectral analysis. Only 6% of the control group, but 64% of the diabetic patients had two or more altered parameters. The authors conclude that persons with high risk of cerebrovascular disease could be identified by Doppler ultrasound examination of common carotid artery.

Arteriosclerosis↗
PubMed1984

Arterial blood flow and resistance in the forearm of arteriosclerotic patients.

Twenty patient with severe atherosclerotic affection of the lower limbs, but without any symptoms of involvement of their upper extremities, and twenty healthy controls were examined. The investigation included measurement of arterial blood flow and resistance in the left forearm at rest and after a three-minute circulatory arrest, using a strain-gauge venous occlusion plethysmograph. Comparison of the results obtained in each group showed statistically significant differences in haemodynamic parameters such as maximal blood flow, resting resistance, and minimal resistance which suggested the presence of vascular changes also in the upper extremities. Arterial resistance proved to be a more sensitive indicator of circulatory disorder than blood flow.

Adolescent↗