PubMed Health⌕ Search

Biomedical subjects

C Nuñez

Publications and source records attributed to C Nuñez.

At least 19 recordsLinked to original sources
PubMed1997

Bioimpedance analysis: evaluation of leg-to-leg system based on pressure contact footpad electrodes.

Conventional single frequency bioimpedance analysis (BIA) systems require technician placement of arm and leg gel electrodes, a suitable location for recumbent measurements, and a separate measurement of body weight. The aim of this study was to evaluate a new single frequency 50 KHz leg-to-leg bioimpedance analysis (BIA) system combined with a digital scale that employs stainless steel pressure-contact foot pad electrodes for standing impedance and body weight measurements. Healthy adults were evaluated for 1) electrode validity and 2) potential for body component estimation. Pressure-contact foot-pad electrode measured impedance was highly correlated with (N = 9, r = 0.99, P < 0.001) impedance measured using conventional gel electrodes applied to the plantar surface of both lower extremities; mean (+/-SD) impedance was systematically higher by about 15 ohms for pressure contact electrodes (526 +/- 56 ohms vs 511 +/- 59 ohms; P < 0.001). Second, the relationship between stature-adjusted leg-to-leg impedance (H2/Z) measured by the new system and two body composition components (total body water by 3H2O dilution (N = 144); and fat-free body mass, by underwater weighing and dual x-ray absorptiometry (N = 231)) was modeled using multiple regression analysis. Correlation coefficients for H2/Z alone versus body composition components were lower for leg-to-leg BIA than for arm-to-leg BIA; correlation coefficients and SEEs became similar for the leg-to-leg and arm-to-leg BIA systems with addition of three covariates (age, gender, and waist/hip circumference ratio) to regression models. The leg-to-leg pressure contact electrode BIA system has overall performance characteristics for impedance measurement and body composition analysis similar to conventional arm-to-leg gel electrode BIA and offers the advantage of increased speed and ease of measurement.

Absorptiometry, Photon↗
PubMed1996

B cells are generated throughout life in humans.

This analysis of B cell development as a function of age reveals a relatively widespread distribution of progenitor B (pro-B), pre-B, and B cells in fetal tissues, and thus supports the idea of a multifocal origin of B lineage cells during embryonic development. From mid-gestation onward, the bone marrow is the major site of B cell generation in humans. A relatively constant ratio of bone marrow precursors to B cells of immature phenotype (CD24highCD10+CD20lowIgD-) is maintained from mid-gestation through the eighth decade of life. The persistence of recombinase gene activity in pro-B cells further attests the sustained production of B cells in bone marrow. Interestingly, a subpopulation of B cells with mature phenotype (CD24lowCD10-CD20highIgD+) accumulates in the bone marrow during childhood, and this becomes the predominant B cell subpopulation in adult bone marrow. This mature population of bone marrow B cells may represent a subpopulation of recirculating B cells that have undergone selection in the periphery.

Adult↗
PubMed1996

Obesity and risk of gallstone development on a 1200 kcal/d (5025 Kj/d) regular food diet.

OBJECTIVE: Previous studies report a greatly increased risk of gallstone formation in obese persons during periods of caloric restriction on very low calorie formula diets. The aim of the present study was to assess the risk of gallstone development in moderately obese patients losing weight on a prescribed 1200 kcal/d (5025 Kj/d) regular food diet. DESIGN AND SUBJECTS: A consecutive sample of 70 men and women (body mass index > 25 kg/m2) (mean +/- SD, 28.9 +/- 2.8 kg/m2) responding to an announcement of an outpatient weight loss program in a major metropolitan research and teaching hospital were enrolled in a meal replacement program which prescribed 1200 kcal/d (5025 Kj/d) consisting of regular foods with approximately 20 g/d fat (15% of kcal) for 16 weeks. RESULTS: Participants who completed the study (n = 34) lost a mean of 5.1 +/- 3.6 kg (p < 0.001) (range, +2.7 kg to -12.5 kg; 6.7 +/- 5.0% of body weight, range +/-3.1% to -17.0%; 0.36 +/- 0.25 kg/week) with no clinically significant adverse effects. There were no discernible new gallstones as measured by ultrasonography during the study period. Liver enzyme blood concentrations did not change significantly after 16 weeks except for alkaline phosphatase, which decreased by 4.5 mu/l from a mean initial level of 72.7 mu/l (p < 0.05). CONCLUSION: Weight loss over 16 weeks on a 1200 kcal/d (5025 Kj/d) regular food/approx 20 g/d fat (15% of kcal) diet was not accompanied by a high rate of gallstone formation in moderately obese persons.

Adult↗
PubMed1995

Human diadenosine 5',5"'-P1,P4-tetraphosphate pyrophosphohydrolase is a member of the MutT family of nucleotide pyrophosphatases.

The cDNA and derived amino acid sequence of human diadenosine 5',5"'-P1,P4-tetraphosphate pyrophosphohydrolase have been determined with the aid of the GenBank Expressed Sequence Tag database. This enzyme possesses a modification of the MutT sequence motif found in certain nucleotide pyrophosphatases. It is unrelated to the enzymes of diadenosine tetraphosphate catabolism found in prokaryotes and fungi.

Amino Acid Sequence↗
PubMed1995

Role of fine-needle biopsy in the diagnosis of hydatid cyst.

The cytopathologic findings in 17 patients with hydatid cyst are reported. All patients but one were referred for evaluation of a tumor mass. In 13 patients the aspirated material was diagnostic of hydatid cyst. In four patients only acellular laminated membranes were present in the aspirate and a presumptive cytopathologic diagnosis of hydatid cyst was made. Subsequent histologic studies confirmed the diagnosis of hydatidosis in all patients. No complications were encountered. Fine-needle biopsy appears a safe diagnostic approach in the evaluation of suspected hydatid disease. The presence of acellular laminated membranes confirm the diagnosis of hydatid cyst.

Adult↗
PubMed1995

Measurement of skeletal muscle: laboratory and epidemiological methods.

Despite skeletal muscle's central role in the pathogenesis of sarcopenia, measurement methods remain underinvestigated and inadequately validated. Our review indicates that skeletal muscle (SM) measurement methods quantify different components and properties of muscle, ranging from the atomic to whole-body levels of body composition. Laboratory methods tend to measure whole body SM (e.g., total muscle protein, muscle cell mass, and adipose tissue-free SM components) while epidemiological methods tend to measure regional muscle (e.g., anatomic SM of an extremity). Advances in computerized axial tomography and magnetic resonance imaging methods now allow accurate estimates of whole body and regional SM and promise to finally permit comprehensive in vivo studies of SM biology and methodology. These imaging methods may help to resolve many of the confusing issues that surround the investigation of this major body composition component.

Adipose Tissue↗
PubMed1994

Excretion of free catecholamines by children.

Excretion of free noradrenaline, adrenaline and dopamine were studied in random urine samples from 221 children (123 boys and 98 girls). The group was subdivided according to age, from birth to 12 years. The catecholamines were analysed by liquid chromatography with electrochemical detector using a 5 microns C-18 Novapack column at 32 degrees C. The values were expressed per kilogram of creatinine. A statistical analysis (non-paired t-test) was carried out in order to define the different reference groups. Children under 2 years were found to have higher noradrenaline excretion than other ages; children under 4 years had higher adrenaline excretion than other ages. Children under 3 years had the highest dopamine excretion, followed by children between 3-6 years, while children from 7 to 12 had the lowest excretion. Appropriate reference intervals were determined from the results.

Aging↗
PubMed1992

Effects of Ro 5-4864 and PK 11195 in rat duodenum and vas deferens.

Ro 5-4864 and PK 11195 inhibit in a concentration-dependent manner carbachol-induced contractions in rat duodenum (IC50: 1.56 +/- 0.07 x 10(-5) M and 1.18 +/- 0.07 x 10(-5) M respectively). The antagonism is non-competitive and is not mediated by peripheral-type benzodiazepine receptors. The Ro 5-4864 effect is modulated by the calcium concentration of the Tyrode-Ringer solution. In the presence of 1 mM NaF/10 microM AlCl3, Ro 5-4864 and PK 11195 do not inhibit carbachol-induced contractions. Moreover, Ro 5-4864 and PK 11195 significantly relax AlF(4-)-induced contractions, with IC50 values of 2.01 +/- 0.12 x 10(-5) M and 1.28 +/- 0.11 x 10(-5) M respectively. This effect is also modulated by the calcium concentration of the medium. Pertussis toxin potentiates the antagonist effects of Ro 5-4864 and PK 11195 on carbachol-induced contractions, but cholera toxin does not affect them. Ro 5-4864 and PK 11195 inhibit 45Ca2+ uptake induced by KCl (120 mM) in rat vas deferens, but do not affect either basal 45Ca efflux or noradrenaline-induced 45Ca2+ efflux. Only high doses of PK 11195 (above 5 x 10(-5) M) are able to produce a slight reduction of the accumulation of inositol phosphates induced by methoxamine in rat vas deferens, while Ro 5-4864 has no significant effect. Finally, Ro 5-4864 and PK 11195 reduce calcium influx, but do not seem to be the only mechanism of the antagonistic effect on carbachol-induced contractions. An alteration of other second messengers, probably cyclic monophosphate nucleotides, may be involved.

Animals↗
PubMed1992

Ovarian follicular cysts: a potential source of false positive diagnoses in ovarian cytology.

The cytology samples of 22 benign ovarian cysts aspirated during laparoscopy (16) or laparotomy (6) were evaluated for clinicopathologic correlations. Clinically, most patients were evaluated for chronic pelvic pain. The cysts ranged in size from 1 to 5 cm (average 2.4 cm), and were described as having benign appearance. Cytologically, small granulosa cells arranged in clusters or isolated had granular cytoplasm with occasional microvacuoles. The nuclei were round to oval, uniform, and eccentrically placed. They had granular chromatin with chromocenters and one to two micronucleoli. Relative nuclear area averaged 50%. Mitoses were present in all but two cases, ranging from 0 to 38 mitoses per 10 high power fields (average 7.2 mitoses per 10 high power fields). Present in some cases were mesothelial cells and histiocytes. Three cases with follow-up histopathology specimens revealed two follicular cysts and a collapsed cyst without discernible lining. The immature appearance of the granulosa cells, the granular chromatin, and the presence of mitoses often suggested cytologically the possibility of a neoplastic process. Recognition of the cytopathology features, knowledge of the clinical history, and the laparoscopic findings may reassure the pathologist about the benign nature of the cysts.

Adolescent↗
PubMed1992

Evaluation of a simple screening test for the quality of drinking water systems.

A simple and inexpensive assay for detection of H2S producing bacteria in drinking water was evaluated in Paraguay. Using an improved preparation procedure, results were basically temperature independent in the range of 22-37 degrees C and correlated well with the presence of total coliform bacteria (96%, 28 degrees C). The assay was not suitable for control of surface water and dug well water due to the frequent presence of non-faecal coliforms. However, it was very suitable for routine control of high quality water systems, like treated community water systems or deep-tube well water, where complete absence of coliforms is required. The H2S-test is very inexpensive and does not require a laboratory technician or special equipment. Its use permits a cost-effective routine control of high quality community water systems in developing countries. In addition, this test turned out to be an effective educational tool for heightening the awareness of people towards dangers of unclean drinking water.

Bacteriological Techniques↗
PubMed1990

Nutritional status and food habits assessed by dietary intake and anthropometrical parameters in anorexia nervosa.

A nutritional study was carried out on 43 adolescents females (5 hospitalized and 38 ambulatory) suffering from anorexia nervosa and on a control group matched for sex and age. The study consisted of an interview, a "48 h. recall" and anthropometric measurements. The results have demonstrated that the nutritional status of anoretics are characterized by a total energy restriction resulting in a drastically reduced intake of macronutrients and selected micronutrients, an increased proportion of energy derived from protein. Finally, preferences and aversions are conditioned by calories content of food.

Adult↗
PubMed1986

Meigs's syndrome and ovarian thecoma in pregnancy. A case report.

Ovarian thecoma is a rare tumor, accounting for less than 1% of all ovarian tumors. Thecomas occur even more infrequently during pregnancy, as evident from the fact that there are only 16 such case reports. A 16-year-old, pregnant, black woman presented with ovarian thecoma, pleural effusion and ascites at 32 weeks' gestation. To our knowledge, this was the first reported case that fulfills the criteria of Meigs's syndrome during pregnancy. Ovarian tumors in pregnancy may have very subtle clinical manifestations, making the diagnosis a challenge. Delivery by cesarean section at term is recommended in these patients for the best maternal and fetal outcome.

Adolescent↗