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G Díaz

Publications and source records attributed to G Díaz.

50 records · Page 3Linked to original sources
PubMed1981

Inotropic effect of harmaline on ventricular and atrial cat myocardium.

In isolated cat heart papillary muscle electrically driven, harmaline (HME) concentrations of 4.15 to 16.6 X 10(-5) M induced a dose dependent negative inotropic effect both at temperatures of 30 and 37 C. In fact, HME decreased both peak tension developed (PTD) and velocity of development of tension (dT/dt) and increased time to peak tension (TPT). The same concentrations induced also a dose-dependent increase of the effective refractory period (ERP). Concentrations of HME lower than 4.15 X 10(-5) M did not show any effect in papillary muscle. In isolated atria of the same cats either spontaneously beating or electrically driven, at 30 C, HME induced a dual inotropic effect. In fact, concentrations of 8.3 X 10(-5) M and 24.9 X 10(-5) M induced an increase in both PTD and dT/dt and lengthening of time to peak tension (TPT). Higher HME concentrations such as 41.5 X 10(-5) M induced a decrease in dT/dt, a negative inotropic effect, but still lengthened the TPT. In both preparations, whenever the dT/dt was depressed the PTD was diminished in spite of the prolongation of TPT. The lesser density of adrenergic innervation and catecholamines concentration in papillary muscle than in atrial myocardium probably explains the negative inotropic action of HME in ventricular myocardium as compared to the dual inotropic effect observed in atria.

Alkaloids↗
PubMed1980

[A theoretical analysis of systemic arterial blood pressure of mammals (author's transl)].

The theoretical reduced exponent b calculated for the arterial pressure, in accordance with Huxley's alometric equation, is 0; however the experimental value has shown different figures. In this paper it is proposed that systemic arterial pressure with exponent zero is in accordance with that of those arteries found at a greater distance of the heart but above cardiac level. We postulate that the cerebral arteries have an experimental exponent b = 0. We have calculated this exponent for the cephalic arterial pressure (arterial pressure at cardiac level minus hydrostatic pressure for cephalic level). With this correction, we have found a better correlation between experimental and theoretical figures in accordance with the theory of biological similarities.

Animals↗
PubMed1976

Neocortex development during severe malnutrition in the rat.

Histological methods (Golgi-Cox and Nissl) were used to study the maturation of the large pyramidal cells of layer V of the occipital cortex in malnourished rats (according to the method of Araya et al.). The main alterations were observed in pyramidal cells of cortical alyer V; These showed a decrease of the number and span of dendritic basilar processes. An increase in cell density was also observed in this layer. We assume that malnutrition during this period of development provokes a derangement which disturbs the process of neuron differentiation, with effects that probably are permanent.

Animals↗
PubMedDate not supplied

[Presence of antibodies against Venezuelan equine encephalitis virus subtype VI in patients with acute febrile illness].

In Argentina, there is no record of human cases produced by Dengue virus (Flavivirus), but Paraguay and Brasil (neighbouring countries) have notified human outbreaks of Dengue Haemorrhagic Fever. In this report, we inform the serological results of a limited human outbreak of a Dengue-like acute illness that occurred in General Belgrano Island, Formosa, Argentina in April 1989. This island is 35 km far from Clorinda city of Paraguay river, with a human population of 150 inhabitants. The weather of this area is humid with abundant rainfall, favouring mosquitoes proliferation. Two samples of serum from 28 human notified cases were studied using hemagglutination inhibition test (HI), complement fixation (CF), and plaque reduction neutralization (NT) test in Vero cell cultures. All tested sera were negative to Dengue, St. Louis encephalitis, Yellow Fever, Bussuquara, Rocio, Eastern and Western Equine Encephalitis arboviruses as well as Influenza and Rubella viruses. By contrast, infection with Venezuelan equine encephalitis virus (VEE), subtype VI-AG80-663 strain was demonstrated (34.5% positive by HI, 39.1% by CF and 51.6% by NT). Seroconversion was detected by NT in six cases and only five were positive by CF. The 26.8% of the sera reacted also with VEE subtype I AB by NT. Considering that no cross reaction were detected in NT with these two subtypes, our results suggest that both viruses are concomitantly circulating in the studied area. Furthermore, the seroconversions detected with AG80-663 strain firmly indicate that during the outbreak this virus subtype was circulating in the island, although we could not assure that it was the causal agent of the acute disease.

Acute Disease↗
PubMedDate not supplied

[The prevalence of hepatitis A, B and C viral markers in the population of Gijón between 26 and 65 years old].

The aim of this study was to know the prevalence of hepatitis A, B and C markers in an adult population in Gijón, Spain. A randomized, transversal sample according to the census was made in a population between 26 and 65 years of age in Gijón, analyzing demographic, epidemiologic and clinical variables, liver function tests, anti-HAV IgG, anti-HBcore and anti-HCV. Of the 476 individuals included a census error was detected in 26 (5.5%) and 340 (71.4%) were studied. Of these anti-HAV IgG was positive in 210 (61.8%) with prevalences of 17.9% from 26 to 30 years (CI: 95%, 11.1%-27.4%), 54.7% from 31 to 35 years (CI: 95%, 41.8%-67%), 73.6% from 36 to 40 years (CI: 95%, 59.4%-84.3%) and 93% (CI: 95%, 86.7%-96.5%) above 40 years of age (p < 0.001). No other significant variables were found adjusted by age groups. With regard to HBV, of the 331 unvaccinated cases, 35 (10.6, CI 95%, 7.6%-14.5%) presented immune markers and 4 (1.2% CI: 95%, 0.4%-3.3%) HBsAg positivity, with all having normal ALT and no viral replication. Anti-HCV was positive in 1.7% (CI: 95%, 0.7-3.9%), being significantly related to IVDA or tattoos. Hypertransaminasemias were detected in 18 (5.3%) being attributed to virus C (27.8%), alcoholism (27.8%) or obesity (44.4%). History of clinical manifestations of acute hepatitis was collected in 9.7% of the cases with no memory of the episode in 84.3% of the anti-HAV IgG positive cases, 79.5% of the anti-HBcore positive cases and 83.3% of the anti-HCV positive cases. The current curve of prevalence of anti-HAV IgG in the Gijón population varies in the decade from 30 to 40 years in age ranging from values discarding prevaccination screening under the age of 30 to levels of minimum susceptibility to infection above the age of 40. The low prevalence of anti-HBcore underestimates its use as prevaccination screening versus HBV in the population of Gijón. The prevalences of HBsAg or anti-HCV thereby make this area a zone of intermediate endemicity, with around 3% of the population being chronically infected by one of these viruses.

Adult↗
PubMedDate not supplied

[Prevalence of Flavivirus antibodies in young voluntary recruits to military service in the province of Formosa, Argentina].

The aim of the present study was to investigate the seroprevalence to Flavivirus, in young people living in risk areas. We analyzed 189 human sera from 3 towns in the Province of Formosa. This area corresponds to the border that limits Brasil and Paraguay and the aim was to search for a possible introduction of Dengue and Yellow Fever from these countries. Serological tests such as haemagglutination inhibition (HI), complement fixation (CF) and neutralization (NT) were performed using St. Louis encephalitis (SLE), Bussuquara, Ilheus, Yellow fever and dengue 1 and 2 viruses. No definite evidence for HI antibodies to dengue and Ilheus was obtained. One serum cross-reacted only with yellow fever and two sera only for Bussuquara by the HI test. Only one serum was confirmed to be positive for Bussuquara by NT test. A total of 22 sera from 189 were positive for SLE by the HI test and 40 were also reactive by the NT test. The seroprevalence measured by HI and NT antibodies was similar in the three departments studied. These results show that SLE virus is present in the North of Argentina with an important value of prevalence so that this agent could play an important role in the febrile infections not virologically confirmed.

Adult↗