Biomedical subjects

J Cortez

Publications and source records attributed to J Cortez.

11 recordsLinked to original sources

PubMed2005

Diurnal biting periodicity of parous Simulium (Diptera: Simuliidae) vectors in the onchocerciasis Amazonian focus.

We describe the hourly patterns of parous biting activity of the three main simuliid vectors of human onchocerciasis in the Amazonian focus straddling between Venezuela and Brazil, namely, Simulium guianense s.l. Wise; S. incrustatum Lutz, and S. oyapockense s.l. Floch and Abonnenc. Time series of the hourly numbers of host-seeking parous flies caught in five Yanomami villages during dry, rainy, and their transition periods from 1995 to 2001 were investigated using harmonic analysis (assuming an underlying circadian rhythm) and periodic correlation (based on Spearman's r). Parous S guianense s.l. showed a bimodal activity pattern, with a minor peak in mid-morning and a major peak at 16:00 h. S. incrustatum exhibited mainly unimodal activity during either early morning or midday according to locality. S. oyapockense s.l. bit humans throughout the day mainly between 10:00 and 16:00 h but also showed bimodal periodicity in some localities. Superimposed on the endogenous, species-specific daily cycles, parous activity showed variation according to locality, season, air temperature and relative humidity, with biting being promoted by warmer and drier hours during wet seasons/periods and reduced during hotter times in dry seasons or transitions. The results are discussed in terms of their implications for blackfly biology and ecology as well as onchocerciasis epidemiology and control.

Animals↗

PubMed2002

Andes virus associated with hantavirus pulmonary syndrome in northern Argentina and determination of the precise site of infection.

Hantavirus pulmonary syndrome (HPS) has been documented in the Salta and Jujuy provinces of northern Argentina since 1991 and 1997, respectively, accounting for almost 50% of the cases of HPS reported in this country. Andes (AND) virus, specifically the AND virus Nort lineage, was previously associated with human disease in this region. Genetic analysis of viral medium RNA segments obtained from 18 HPS cases showed the existence of three AND virus Nort sublineages co-circulating in these two provinces. They showed a nucleotide sequence diversity of up to 11.1% between the sublineages. The putative site of infection of one of these cases (Sal3/97) was determined. A 100% nucleotide sequence identity was observed between the viral sequence found in patient Sal3/97 and in two virus-positive Oligoryzomys chacoensis captured in the same place where the case lived and worked. These results indicated the putative site of infection and identified this rodent species as the source of infection.

Argentina↗

PubMed2001

Human onchocerciasis in the Amazonian area of southern Venezuela: spatial and temporal variations in biting and parity rates of black fly (Diptera: Simuliidae) vectors.

We investigated some entomological factors underlying altitudinal prevalence variation in the Venezuelan Amazonia human onchocerciasis focus. Spatial and temporal variation in relative abundance, daily biting rate, proportion of parous flies, and monthly parous biting rate were studied for the three main simuliid vectors (based on their vectorial competence: Simulium oyapockense s.l. Floch & Abonnenc approximately = S. incrustatum Lutz << S. guianense s.l. Wise). Yanomami villages were selected among sentinel communities of the ivermectin control program, representing hypo- to hyperendemicity conditions of infection. Spatial variation was explored via increasing village altitude on two river systems (A: Ocamo-Putaco and B: Orinoco-Orinoquito). Temporal variation was studied between 1995 and 1999 by sampling the biting population during dry and rainy mouths. Environmental variables included monthly rainfall and maximum river height. Simuliid species composition itself varied along the altitudinal and prevalence gradient. S. oyapockense s.l. prevailed below 150 m. Above this altitude and up to 240 m, S. incrustatum and S. guianense s.l. became more frequently and evenly collected along A but not along B, where S. incrustatum remained absent. The daily biting rate of S. oyapockense s.l. was higher during the dry season along A, whereas the converse took place along B. Daily biting rate of S. incrustatum was lowest during early rains. By contrast, the daily biting rate of S. guianense s.l. was highest during this period. There was a significant negative cross-correlation between proportion of parous of S. oyapockense s.l. and river height (2 and 3 mo lagged), whereas this variable (1 and 2 mo lagged) was positively correlated with the proportion of parous flies for S. incrustatum. Monthly parous biting rate values suggest that the months contributing most to onchocerciasis transmission in the area are likely to be the dry season and the transition periods between seasons.

Animals↗

PubMed2000

Increased CD38 expression is associated with favorable prognosis in adult acute leukemia.

CD38 is expressed in acute lymphoblastic leukemia (ALL) and acute myelogenous leukemia (AML) blasts and its prognostic significance is unknown. We investigated CD38 expression in 304 AML and 138 ALL patients. CD38 was lower in AML-M3 compared to other FAB subtypes (5% vs. 41%; P < 0.001), but was similar among ALL subtypes (56.6%; P = 0.69). Ph + ALL and AML with t(15; 17) patients showed lower CD38 expression than the other cytogenetic groups. Overall survival favored AML and ALL patients with higher CD38 levels. Multivariate analysis revealed CD38 expression to be an independent outcome predictor in AML, but not in ALL.

ADP-ribosyl Cyclase↗

PubMed2000

Prevention of falls and fall-related fractures through biomechanics.

Falls and fall-related injuries are a major health problem for elderly people. Biomechanical studies provide important insight into the cause of such events and reveal new techniques for preventing them. The topics reviewed in this article include balance recovery, safe landing responses, impact forces during falls, and fracture prevention through exercise programs, hip pads, and energy-absorbing floors.

Accidental Falls↗

PubMed1995

Effects of dietary fats, alpha-tocopherol and beta-carotene supplementation on aortic ring segment responses in the rat.

We examined the effects of vitamin supplement on the vascular smooth muscle response of rats fed four different oil diets, after a 20-day feeding period. Male Sprague Dawley rats were fed diets containing 15% of each hazelnut, corn, olive or fish oils, with/without 30 mg/kg beta-carotene and 500 mg/kg dl-alpha-tocopherylacetate. After the feeding period, plasma retinol, alpha-tocopherol, cholesterol, HDL and triacylglyceride concentrations and aortic ring segment responses to KCl (70 mM), phenylephrine and acetylcholine (maximal tension, maximal relaxation and pD2 or -log ED50) were measured. The intake of vitamin-supplemented diets increased plasma alpha-tocopherol levels in rats fed hazelnut or fish oil, while retinol concentration was unaffected. Also, the vitamin supplement counteracted the specific hypercholesterolemic effect of hazelnut oil intake. The addition of a vitamin supplement augmented acetylcholine pD2 values in aortic ring segments of rats fed corn oil (p < 0.001), revealing that arteries were more prone to induced relaxation under this dietary condition. It also lowered the maximal ring tension in response to phenylephrine in rats fed hazelnut or olive oil. These results indicate that the intake of alpha-tocopherol and beta-carotene supplement can modulate the effect of dietary fat type on aortic ring segment responses to pharmacological agents in the rat.

Acetylcholine↗

PubMed1994

Evidences for the presence of chymotrypsin-like activity in human spermatozoa with a role in the acrosome reaction.

The effect of chymotrypsin inhibitors and substrates on the human sperm acrosome reaction stimulated by the human zonae pellucidae or follicular fluid were evaluated. Motile spermatozoa, selected by a Percoll gradient, were incubated at 1 x 10(7) cells/ml, 37 degrees C, and 5% CO2. After 4.5 hr, the chymotrypsin inhibitor TPCK (N-Tosyl-L-Phenylalanine-Chloromethyl Ketone) or the substrate ATEE (N-Acetyl-L-Tyrosine Ethyl Ester) were added for 30 min. Then, four oocytes were added and the percentage of acrosome-reacted spermatozoa on the zona was determined. TPCK and ATEE inhibited the zona pellucida-induced acrosome reaction. The chymotrypsin inhibitors TPCK and chymostatin and the chymotrypsin substrates ATEE, BTEE (N-Benzoyl-L-Tyrosine Ethyl Ester), Succinyl-Ala-Ala-Phe-7-Amido-4-Methyl-Coumarin (Suc-Ala-Ala-Phe-AMC), and Succinyl-Leu-Leu-Val-Tyr-7-Amido-4-Methyl-Coumarin (Suc-Leu-Leu-Val-Tyr-AMC) inhibited the human follicular fluid-induced acrosome reaction. Sperm extracts exhibited hydrolytic activity toward Suc-Ala-Ala-Phe-AMC and Suc-Leu-Leu-Val-Tyr-AMC. This enzyme activity was abolished by TPCK and chymostatin, was independent of Ca2+, and was not modified by 1,10 phenanthroline. In addition, the activity was present in the supernatant after the acrosome reaction was induced with calcium ionophore and in epididymal spermatozoa recovered from the cauda region. Electron microscopic observations indicated that the inhibitors prevented the membrane events of the acrosome reaction. These data suggest an association between human spermatozoa and chymotrypsin-like activity with a possible role in the acrosome reaction.

Acrosome↗

PubMed1994

The management of proximal hypospadias using a 1-stage hypospadias repair with a preputial free graft for neourethral construction and a preputial pedicle flap for ventral skin coverage.

A total of 77 patients with proximal hypospadias underwent a 1-stage hypospadias repair using a preputial free graft for neourethral construction and a preputial pedicle flap for ventral skin coverage. Of the patients 84% achieved excellent functional and cosmetic results with 1 procedure.

Follow-Up Studies↗

PubMed1991

Molecular differentiation of two different translocations producing two apparent Ph chromosomes in a patient with CML.

A case of chronic myelogenous leukemia (CML) is described whose leukemic cells appeared to contain two Philadelphia (Ph) chromosomes originating from different translocations involving the two chromosomes 22. The karyotype of the affected cells, established on two different occasions, was: 46,XY,t(9;22)(q34;q11),t(15;22)(p11;q11) with no normal chromosomes 22 and only one 9q+ in each of 115 marrow cells examined. The same findings were present in 50 peripheral blood cells cultured without phytohemagglutinin (PHA) stimulation. When stimulated with PHA, a normal male karyotype was present in the 11 cells examined. There were no additional chromosomal abnormalities and no indication of a blastic crisis after nearly 1 year following the original study. Analysis of the breakpoint cluster region (bcr) on chromosome 22 in the DNA of the affected cells (marrow) revealed evidence for one rearranged chromosome 22 and one normal chromosome 22, indicating that the t(15;22) was not due to the usual Ph translocation seen in CML. The results point to the crucial usefulness of molecular analysis in confirming cytogenetic results related to Ph translocations in CML.

Adult↗

PubMed1983

Myocardial contusion following nonfatal blunt chest trauma.

Currently available diagnostic techniques for myocardial contusion following blunt chest trauma were evaluated. We investigated 30 patients prospectively over a period of 1 year for the presence of myocardial contusion. Among the 30 patients, eight were found to have myocardial contusion on the basis of abnormal electrocardiograms, elevated creatine phosphokinase MB fraction (CPK-MB), and positive myocardial scan. Myocardial scan was positive in seven of eight patients (87.5%). CPK-MB fraction was elevated in four of eight patients (50%). Definitive electrocardiographic changes were seen in only two of eight patients (25%). It appears that myocardial scan using technetium pyrophosphate and CPK-MB fraction determinations are the most reliable aids in diagnosis of myocardial contusion following blunt chest trauma.

Adult↗

PubMedDate not supplied

[Atherosclerosis. Old problem, new perspectives].

Atherosclerosis is the major cause of mortality in the population of the, so called, developed countries of western culture. Since the first half of this century, hypercholesterolemia was the hallmark for the investigation of atherosclerosis, improving the level of knowledge about the complex metabolism of lipoproteins. The occurrence of atherosclerosis in normolipidaemic subjects, and the relationship between this illness, other dysmetabolic features and certain infectious agents, led to the reformulation, in the last decade, of the pathophysiological archtypes, atherosclerosis was included in the group of the inflammatory processes. The inflammatory response to aggression of the arterial wall is the innovative issue of atherosclerosis investigation and laboratory follow-up in the new millennium.

Arteriosclerosis↗