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G Diaz

Publications and source records attributed to G Diaz.

108 records · Page 6Linked to original sources
PubMedDate not supplied

Uneven copper distribution in the human newborn liver.

The pattern of copper distribution in human newborn liver was investigated by histochemical methods (rhodamine, orcein and rubeanic acid) and by atomic absorption spectroscopy. A significant correlation (p less than 0.005) was found between the degree of histochemical positivity and the copper concentration found by atomic absorption spectroscopy. In the majority of the 30 livers examined (first group), the copper concentration was much higher than that of normal adult liver, although exhibiting striking individual differences. No correlation between the copper content and sex, body weight or gestational age was found. From a second group of five livers, longitudinal tissue slices 0.5 cm thick were partitioned into regular blocks of about 0.5 gm, which were individually analyzed by atomic absorption spectroscopy. Copper appeared unevenly distributed within each liver, with marked differences even between adjacent blocks. However, a consistent tendency of copper to accumulate in the left lobe more than in the right one was evident. Five additional blocks, one for each liver, were further partitioned into 10 small specimens of a final size (0.05 gm), comparable to that of a needle biopsy. Even at this sampling level, consisting of tissue fragments taken from a small tissue area, the copper concentration appeared quite irregularly distributed. These findings may be considered for two different aspects: (a) the biological implications of the pattern of copper accumulation in different lobar and lobular liver compartments and (b) the statistical inference, for diagnostic purposes, of the mean liver copper content from measurements of single percutaneous biopsy specimens.

Age Factors↗
PubMedDate not supplied

Calcitonin gene-related peptide in the human trigeminal sensory system at developmental and adult life stages: immunohistochemistry, neuronal morphometry and coexistence with substance P.

The distribution of calcitonin gene-related peptide (CGRP) has been examined by the indirect immunofluorescence technique in the Gasserian ganglion and spinal nucleus of the human trigeminal nerve. In the ganglion CGRP is present in almost 50% of primary sensory neurons, in varicose and non-varicose nerve fibres and in pericellular basket-like plexuses around non-immunoreactive ganglionic perikarya. Morphometric analysis reveals that the CGRP-positive neuronal population is heterogeneous in cell size. Observation of specimens from subjects at fetal, perinatal and adult life stages reveals that the percentage of CGRP-immunoreactive cells reaches a maximum at perinatal stages and then remains constant, declining only in old age. Pericellular basket-like nerve fibres are detectable only in fetal and pre-term and full-term newborn tissue. Coexistence between CGRP and substance P (SP) occurs, SP being present in about one quarter of the CGRP-immunoreactive neurons and CGRP being localized in a little more than half of the SP-immunoreactive neurons. However, perikarya, nerve fibres and pericellular fibres containing only one or other peptide are also present. Bundles of immunoreactive fibres and dot-like nerve terminals occur in the spinal tract and superficial and deep regions of the spinal trigeminal nucleus. A particularly dense plexus is present in the peripheral nuclear layers. Double immunostaining shows a similar regional distribution for SP. However, in inner substantia gelatinosa the density of CGRP-immunoreactive fibres is much higher than that of SP-immunoreactive ones. The results obtained add information to our knowledge of the organization of neurochemically identified neurons in the human trigeminal sensory system.

Adolescent↗
PubMedDate not supplied

Sardinian alcohol-preferring rats prefer chocolate and sucrose over ethanol.

The present study was aimed at determining whether the concurrent availability of highly palatable fluids (i.e., a chocolate-flavored drink and a sucrose solution) would alter voluntary ethanol drinking in selectively bred, alcohol-preferring sP and -nonpreferring sNP rats. Ethanol intake occurred under the three-bottle, free choice regimen between 10% (v/v) ethanol solution, tap water, and the palatable fluids for 24 h per day. When rats were given ethanol and water, but no alternative fluids, mean ethanol intake in sP rats ranged between 6 and 7 g/kg per day and mean preference ratio was steadily higher than 80%, whereas mean ethanol intake and preference ratio in sNP rats were constantly lower than 0.3 g/kg and 5%, respectively. In the presence of either the chocolate-flavored drink or sucrose solution, both prepared as isocaloric to the ethanol solution, absolute ethanol intake in sP rats declined by 60-70%; similarly, the preference ratio was reduced by 80-90%. Ethanol intake in sNP rats was unaffected by the simultaneous presentation of either palatable fluids. The results of the present study closely replicate those previously reported in genetically selected, ethanol-preferring HAD rats; however, they differ from those of ethanol-preferring P rats, which were reported to maintain high levels of ethanol intake and preference in the presence of highly palatable fluids. These results are discussed in terms of a) an alternative reinforcement partially substituting for the reinforcing properties of ethanol in sP rats, resulting in a less urgent need of ethanol, and b) genetic animal models of alcoholism diverging in some neurochemical and behavioral traits (e.g., response to the presentation of palatable fluids), which might parallel the different types of alcoholism observed in humans.

Animals↗
PubMedDate not supplied

Experimental neuroinvasiveness of wild and laboratory Junin virus strains.

The neuroinvasiveness of Candid 1 and XJCL3 laboratory strains and CbalV4454 and CbaFHA5069 wild strains of Junin virus was studied in albino mice, guinea pigs, and a South American wild rodent, Calomys musculinus (Cm), of different ages inoculated by a non-neural route. Infectivity in brain, blood and organs, as well as lethality, were determined. The results with the 3 hosts indicate that Junin virus neuroinvasiveness is virus-strain-dependent, host species- and age-dependent, with the Candid 1 strain proving to be the least neuroinvasive of the strains studied. The lethal efficiency index (log PFU/LD50) in 2-day old albino mice and the neuroinvasiveness index (Log PFU/ND50) in 6 +/- 1 day-old Cm of the various strains using the intraperitoneal (ip) route could therefore be useful markers of Junin virus neuroinvasiveness. Moreover, different patterns of infection were established using the results of the presence of infectious virus in brain and viraemia in the 3 hosts. In nearly all cases, virus neuroinvasion was present without detectable viraemia (virus in plasma). Current evidence leads to the assumption that virus might reach the brain associated with the white cells in blood (undetectable by conventional isolation methods) or by another possible mechanism of neuroinvasion which is not haematogenous.

Animals↗
PubMedDate not supplied

Effect of dexamethasone on lymphocyte subpopulations in premature infants with bronchopulmonary dysplasia.

OBJECTIVE: This study was designed to determine the effect of dexamethasone treatment on peripheral blood lymphocyte counts and subpopulations in premature infants with bronchopulmonary dysplasia (BPD). STUDY DESIGN: Peripheral blood lymphocyte subpopulations in 12 premature infants with BPD were analyzed before treatment with a 6-week course of dexamethasone (day 0), on days 3 and 10 of treatment, and 2 weeks after discontinuing dexamethasone therapy (day 56). Lymphocyte immunophenotypes were determined using direct two-color immunofluorescent staining followed by flow cytometry. RESULTS: The percentage of lymphocytes was significantly lower on days 3 (17.55 +/- 2.55) and 10 (20 +/- 11.8) of dexamethasone therapy compared with before (30.36 +/- 6.41) or after treatment. The percentage of T cells was significantly lower on days 3 and 10 of dexamethasone therapy (mean +/- SEM; 58.09 +/- 1.93 and 60.09 +/- 2.47, respectively) compared with before (67.09 +/- 4.24) or after treatment. The absolute number of T cells was significantly lower on day 10 of therapy. The percentage of CD4+ cells was significantly lower on days 3 (38.91 +/- 2.49) and 10 (40.45 +/- 2.24) of therapy, and this decrease persisted after dexamethasone was stopped (36.73 +/- 3.41). The absolute number of CD4 cells was significantly lower on day 10 (1328 +/- 216) of therapy and reached a nadir on day 56 (1143 +/- 106). Similarly, the CD4/CD8 ratio was also significantly lower on days 3 and 10 of treatment (1.56 +/- 0.18 and 1.64 +/- 0.14, respectively) and reached a nadir on day 56 (1.04 +/- 0.13). CONCLUSION: Dexamethasone significantly reduced the percentage and absolute number of lymphocytes, T cells, and CD4 cells, as well as the CD4/CD8 ratio. A reduction in CD4 cells and in the CD4/CD8 ratio persisted 2 weeks after dexamethasone therapy was stopped. In contrast, the absolute number of B cells increased transiently, and CD8 cells were unaffected by dexamethasone. This alteration in lymphocyte subpopulations may help account for the clinically beneficial anti-inflammatory effect of dexamethasone in the treatment of BPD complicated by respiratory failure. The dexamethasone-induced decrease in CD4 cells may also increase the susceptibility of these infants to infection.

B-Lymphocytes↗
PubMedDate not supplied

Constant absolute ethanol intake by Sardinian alcohol-preferring rats independent of ethanol concentrations.

The present study was designed to evaluate ethanol drinking behaviour in Sardinian alcohol-preferring (sP) and Sardinian alcohol-non-preferring (sNP) rats in the presence of different ethanol concentrations. Ethanol intake was tested under the two-bottle, free-choice regimen and continuous access schedule. Ethanol-naive sP and sNP rats were initially given ethanol solution at the standard, constant concentration of 10% (v/v) for 8 consecutive days (Phase 1). As expected, daily ethanol intake in sP rats rose from 4 to approximately 6 g/kg; in contrast sNP rats consumed < 10 g/kg/day ethanol. Subsequently, an ascending series of ethanol concentrations, ranging from 3 to 60% (v/v), was presented to sP and sNP rats over a 28-day period (Phase 2). At concentrations varying from 7 to 30%, sP rats consumed constant amounts of absolute ethanol per kg of body weight (approximately 6.0 g/kg/day). Daily ethanol intake in sNP rats remained constantly lower than 1.0 g/kg, irrespective of the ethanol concentration. Data from Phase 2 demonstrate the ability of sP rats to precisely adjust daily ethanol intake and support the hypothesis that voluntary ethanol drinking in sP rats is sustained by specific pharmacological effects of ethanol.

Alcohol Drinking↗
PubMedDate not supplied

Lingual osteoma.

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Choristoma↗
PubMedDate not supplied

Sex-linked strategies of human reproductive behavior.

We present data on fertility characteristics in the Venezuelan population for each sex separately, allowing a detailed comparative analysis of the variance in fertility between males and females. We show that the fertility distribution for both sexes is discontinuous, that the average female has a larger number of offspring per individual than the average male, and that highly fertile males outnumber highly fertile females so that the total number of offspring produced by males and females is balanced. Results indicate that a few males are responsible for a relative higher fertility of the average female and that interactions between polyandric females with monogamic and polygynic males are common. Among the Yanomami, a relatively unacculturated hunter-gatherer-horticulturist tribe, similar differences in fertility distribution of both sexes are apparent. The data suggest that human populations contain statistically distinct subpopulations, with different reproductive strategies, suggesting the existence of complex interactions among human populations which are not evident from the study of individuals or groups.

Adolescent↗
PubMedDate not supplied

Dental development in Sardinian children.

A cross-sectional study of tooth maturation was carried out in a group of 382 healthy children (178 boys and 204 girls) from Sardinia. A single orthopantomogram was examined for each patient and the development of permanent mandibular canines, premolars, and molars was evaluated according to Moorrees' method [Moorrees CFA, Fanning EA, Hunt EE: J Dent Res 42:1490-1502, 1963] Dental maturity scores and chronological ages were processed by linear regression analysis. Significant differences were observed in the timing of tooth development between boys and girls. A visual comparison with North American children revealed appreciable differences between the two populations, accounting for a delayed dental maturation in Sardinian children.

Cross-Sectional Studies↗