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D Gonzalez

Publications and source records attributed to D Gonzalez.

At least 55 records · Page 3Linked to original sources
PubMed1993

Higher plant mitochondria encode an homologue of the nuclear-encoded 30-kDa subunit of bovine mitochondrial complex I.

We describe the structure and expression of a wheat mitochondrial gene, which codes for a subunit of mitochondrial NADH dehydrogenase. The deduced protein sequence has 70% similarity to the 30-kDa subunit of bovine mitochondrial complex I and 65% similarity to the 31-kDa subunit of Neurospora crassa complex I, components of the iron-sulfur-protein fraction, both nuclear-encoded proteins. We named this wheat mitochondrial gene as nad9. The wheat nad9 gene is transcribed in a single mRNA of 0.9 kb that is edited (C-to-U conversions) in 14 positions. Transcript mapping revealed that the first ATG codon is just 20 nucleotides downstream of the mRNA 5' end and that the 3' end is just 23 nucleotides downstream of the nad9 stop codon. The expression of the nad9 gene in plant mitochondria was studied. Polyclonal antibodies prepared against a wheat NAD9 fusion protein specifically recognise the 30-kDa subunit of bovine mitochondrial complex I and a 27.5-kDa protein in the membrane fractions of wheat, maize and common bean mitochondria, whereas the same serum recognizes a 30-kDa protein in the mitochondria of pea, chickpea and lentil.

Amino Acid Sequence↗
PubMed1993

Hypothalamus-pituitary-ovarian axis in cyclic rats lacking progesterone actions.

Antagonizing diestrous progesterone actions in cyclic rats by s.c. injections of the antiprogesterone RU486 (2 mg twice a day from metestrus through proestrus) increased LH and decreased FSH basal serum concentrations. Ovariectomy at metestrus (0800 h) increased serum levels of both gonadotropins in controls and reversed the RU486-induced dissociation of basal gonadotropin secretion. RU486-dissociated gonadotropin secretion is also dependent upon LHRH, since treatment (s.c.) with 1 mg GnRH antagonist (ORG 30276) twice a day on metestrus and diestrus completely prevented both the RU486-induced increase in LH and the decrease in FSH serum concentrations. The LHRH content in the medial basal hypothalamus and median eminence increased on proestrous morning in RU486-treated rats. The LH pituitary response to an exogenous i.v. bolus of 25 ng LHRH (Peninsula 7201; Peninsula Laboratory, Inc., Merseyside, UK) at 1700 h on diestrus was enhanced in rats treated with RU486. No differences in pituitary FSH response were noted with respect to oil-injected rats. The pituitary content of both gonadotropins decreased in RU486-treated rats on proestrous morning. All these effects due to RU486 in cyclic rats were reversed by ovariectomy. Testosterone serum levels increased significantly from diestrus onward, and the estradiol concentration increased on proestrous morning in RU486-treated rats. Ovariectomy as well as LHRH antagonist treatment eliminated the effects of RU486 on ovarian steroid production. Moreover, antiestrogen tamoxifen treatment reversed RU486-dissociated gonadotropin secretion, while antiandrogen flutamide treatment had no effect. The results of this experiment have confirmed previous findings that RU486 treatment dissociates basal gonadotropin secretion in cyclic rats. In addition, the present results show that: (1) this effect of RU486 is not due to a direct effect of this compound or to the blockade of progesterone action at a central level; (2) the effect of RU486 on pituitary gonadotropin secretion depends on ovarian substances other than progesterone and LHRH, since it is reversed by ovariectomy and completely abolished by LHRH antagonist treatment; (3) the reduction in FSH serum levels in rats treated with RU486 seems to be exerted by inhibin and estradiol at the pituitary level by reducing FSH synthesis and secretion; and (4) the hypersecretion of LH in rats treated with RU486, as compared to that resulting from ovariectomy, seems to be the consequence of, first, a lack of progesterone inhibitory action on LH secretion, and, second, an inappropriate feedback system involving increased hypothalamic LHRH activity and pituitary sensitivity to LHRH of moderately high levels of estradiol in the presence of abnormally high levels of testosterone.

Amino Acid Sequence↗
PubMed1993

Alterations in activity following alcohol administration during the third trimester equivalent in P and NP rats.

There is considerable variation in the consequences of alcohol abuse during pregnancy on infant outcome. Although it is clear that a number of factors contribute to this variability, one hypothesis that has received recent attention is the role of genetic differences in response to alcohol. This study examined activity levels in the alcohol-preferring (P) and alcohol-nonpreferring (NP) rats following neonatal alcohol exposure. Although these lines were selectively bred for differences in voluntary alcohol consumption, they also differ in their sensitivity and tolerance to alcohol. The P and NP offspring were artificially reared and administered ethanol (either 6 or 4 g/kg/day) from postnatal day 4 (PN 4) until PN 10 via intragastric cannula. An artificially reared isocaloric maltose group and a normally reared control group were also included. From PN 18 to PN 21, subjects were tested daily for 30 min in an automated activity monitor. Exposure to either the 4 or 6 g/kg dose of ethanol resulted in overactivity in P rats. However, only the 6 g/kg dose group displayed overactivity among the NP offspring. Furthermore, the level of overactivity displayed by the alcohol-exposed P rats was significantly greater than that displayed by the alcohol-exposed NP rats. These data suggest that genetic differences in response to alcohol may be a predictor for the behavioral teratogenic effects of alcohol.

Alcohol Drinking↗
PubMed1993

Characterization of a new sporulation factor in Bacillus subtilis.

We report the existence and partial purification of sporulation factor, which stimulates sporulation of Bacillus subtilis at low cell density. Proline or arginine is required for stimulation under the conditions of our assay. Sporulation factor is a small heat-stable substance produced by the cells during exponential growth phase. It is required in small amounts and is resistant to various proteolytic agents. Several spo mutants were tested for the ability to produce functional sporulation factor. All of these mutants produce factor and do not sporulate in the presence of factor from wild-type cells. Sporulation factor is not involved in the induction of alpha-amylase synthesis at the initiation of sporulation.

Arginine↗
PubMed1992

Evolutionary relationships within the fungi: analyses of nuclear small subunit rRNA sequences.

Nucleotide sequences of the small subunit ribosomal RNA (18S) gene were used to investigate evolutionary relationships within the Fungi. The inferred tree topologies are in general agreement with traditional classifications in the following ways: (1) the Chytridiomycota and Zygomycota appear to be basal groups within the Fungi. (2) The Ascomycota and Basidiomycota are a derived monophyletic group. (3) Relationships within the Ascomycota are concordant with traditional orders and divide the hemi- and euascomycetes into distinct lineages. (4) The Basidiomycota is divided between the holobasidiomycetes and phragmobasidiomycetes. Conflicts with traditional classification were limited to weakly supported branches of the tree. Strongly supported relationships were robust to minor changes in alignment, method of analysis, and various weighting schemes. Weighting, either of transversions or by site, did not convincingly improve the status of poorly supported portions of the tree. The rate of variation at particular sites does not appear to be independent of lineage, suggesting that covariation of sites may be an important phenomenon in these genes.

Animals↗
PubMed1992

Effects of 1 M NaCl cerebroventricular injection on renal and baroreceptor reflex functions.

Our purpose was to study the influence of the stimulation of the cerebroventricular system on some mechanisms related to hydrosaline equilibrium and blood pressure regulation. Renal function and blood pressure (group 1) as well as the baroreceptor reflex (group 2) were studied. In group 1, we measured diuresis, natriuresis, creatinine clearance, lithium clearance, and blood pressure in control rats and after stimulation of the cerebroventricular system with 1 M NaCl solution. In group 2, we evaluated the baroreceptor reflex, producing an increase of blood pressure with an injection of phenylephrine to obtain baroreceptor reflex curves--characterized by threshold, point of inflection, heart period range, gain, and systolic pressure corresponding to half the heart period range (SBP50)--in control and experimental rats injected with saline and 1 M NaCl solution, respectively. In group 1 experimental rats, we observed a significant increase in diuresis, natriuresis, blood pressure, and glomerular filtration rate. A substantial increase was also registered in sodium filtered load and reabsorbed sodium in the proximal convoluted tubule and distal nephron. No differences were observed either in fractional proximal tubule or in distal nephron sodium reabsorption. In group 2 experimental rats, mean arterial blood pressure, threshold, point of inflection, and SBP50 were significantly higher than in control rats. By contrast, a decrease in gain and heart period range was observed. No difference was obtained in heart rate. Our results demonstrate that the increase of the natriuresis is due, at least in part, to an increase in sodium filtered load.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1991

Medical coverage of endurance events.

Supervision of medical coverage at endurance events is a complex undertaking, well suited to family physicians by virtue of their training and enhanced by their flexibility to function as gatekeepers of a wide-ranging support network. Ideally, the medical director is involved from the beginning in the planning of an endurance event and will be primarily responsible for staffing, facilities, equipment and supplies, communications, and transportation. In this article, I have presented an overview of the medical problems encountered in endurance events (Table 6). These events are increasing in popularity, and physicians should be aware of the complexities and responsibilities of medical management to ensure the health and safety of all participants.

Athletic Injuries↗
PubMed1990

Expression of beta-nerve growth factor in cultured cells derived from the hypothalamus and cerebral cortex.

Although the synthesis of nerve growth factor (NGF) in brain regions innervated by magnocellular cholinergic neurons of the basal forebrain is well documented, the cell type(s) able to produce NGF in the central nervous system (CNS) remain only partially characterized. Moreover, little is known regarding the ability of brain areas not innervated by magnocellular cholinergic neurons to express NGF protein. The hypothalamus, which controls the endocrine system, is one of such regions. Primary culture of mixed populations of cells from the fetal hypothalamus were used to identify the presence of NGF in this brain area. Immunocytochemistry revealed that hypothalamic oligodendrocytes and a subpopulation of neurons expressed the NGF protein. In contrast, astrocytes were either immunonegative or equivocally stained. To define whether synthesis of NGF is restricted to a particular cell type, cultures of purified astrocytes, oligodendrocyte progenitor (oligoP) cells and neurons were utilized. They were obtained from the neonatal cerebral cortex to ensure an adequate yield of glial cells. Virtually the entire population of cerebral oligoP cells were found to express NGF protein. In contrast, and similar to hypothalamic astrocytes, cerebral type I astrocytes isolated at the same time as oligoP cells exhibited little or no NGF staining. When type I astrocytes were induced to differentiate in the presence of a serumless, chemically defined medium, a subpopulation of the culture became more robustly positive for the NGF protein. Contrasting with these differences in NGF immunoreactivity, Northern analysis of RNA isolated from purified cerebral type I astrocytes, oligoP cells and neurons demonstrated that NGF mRNA was expressed in each of these cell types at approximately the same levels. The results indicate that: (a) when placed in culture, each of the major cell types within the CNS has the capability of transcribing the NGF gene, and (b) despite similar NGF mRNA levels the cellular content of NGF protein is greater in a subpopulation of neurons and in oligodendrocytes than in astrocytes, suggesting differences in NGF post-transcriptional regulation between these cell types. In addition, the presence of NGF in hypothalamic cells suggests that NGF may be involved in the regulation of specific hypothalamic neuronal systems.

Animals↗
PubMed1990

Praziquantel treatment of porcine brain and muscle Taenia solium cysticercosis. 1. Radiological, physiological and histopathological studies.

Porcine Taenia solium cysticercosis, recognized as a model of the human disease, was used to analyze the effect of the anthelminthic drug praziquantel on hosts and parasites. The drug (50 mg/kg daily) was given over 15 days in the feed of 13 cysticercotic and 9 control pigs. Changes in the number, size and appearance of brain parasites were seen by computerized tomography immediately after the last dose of praziquantel, although not all cysticerci had disappeared by day 47 following the end of the treatment. Muscle parasites became small and hyperdense shortly after treatment and disappeared from tomographic images afterwards. No alterations were found in EEGs or in brain-stem auditory and somatosensory evoked potentials. Muscle cysticerci showed increasing degrees of degeneration with time after treatment, and an augmented inflammatory reaction was concomitantly observed. In contrast, more heterogeneous results were obtained in parasites lodged in the brain, since viable cysts and less intense inflammatory reactions were found in the brain at different times after treatment. Physiological evaluation of the parasites showed that evagination was inhibited immediately after treatment and that oxygen consumption decreased with time. The results of this investigation suggest that praziquantel damages cysticerci and that the inflammatory reaction destroys and eliminates them.

Animals↗
PubMed1990

Genetics of factors affecting the life history of Drosophila melanogaster. IV. Cytoplasmic/maternal factors affect egg insertion behavior.

The genetic basis of insertion behavior of laboratory strains of Drosophila melanogaster was examined. Reciprocal crosses among five strains revealed a significant effect of interaction between cytoplasmic/maternal factors and the chromosomal genotype in determining the insertion tendency, thus complicating the characterization of the dominant/recessive nature of the insertion genes. The majority of heterozygous combinations demonstrated dominance or partial dominance for the higher insertion tendency over low insertion, while a few combinations produced results to the contrary. These could be due to a more complex genetic basis of insertion behavior than a simple dominant/recessive relationship or else to the cytoplasmic/maternal-chromosome interactions. Examination of the effects of each chromosome revealed the greatest contributions to insertion tendency from the second and third chromosomes, with a significant effect of interaction or nonadditivity of the insertion genes in these two chromosomes in the genotypes tested. The X and fourth chromosomes appear to contribute a small effect in some strains.

Animals↗
PubMed1989

Regression of left ventricular hypertrophy in hypertension. Effects of prazosin therapy.

Left ventricular hypertrophy is a common consequence of chronic hypertension. Although the hypertrophic response can be considered an adaptive mechanism in the initial stages, its progression is associated with increased cardiovascular morbidity and mortality rates. Therefore, reversal of left ventricular hypertrophy may provide considerable clinical benefits to hypertensive patients. Although treatment of hypertension per se is important, blood pressure alone may not explain the course of the hypertrophic process. Not all antihypertensive drugs cause a reversal of hypertrophy, though they may produce equal effects on blood pressure. Factors other than the severity of blood pressure may play a role in the genesis of left ventricular hypertrophy. Adrenergic inhibitors cause its regression, whereas direct vasodilators may promote progression. In this study, therapy with the alpha-adrenergic inhibitor prazosin resulted in significant regression of left ventricular hypertrophy in a group of patients with moderate-to-severe hypertension. This study utilized a new technique--[123I]phenylpentadecanoic acid myocardioscintigraphy--to measure the left ventricular mass. In this study, it was shown that monotherapy with prazosin produced significant relative reductions in systolic and diastolic blood pressure, along with significant reductions in left ventricular mass.

Blood Pressure↗
PubMed1989

Genetics of factors affecting the life history of Drosophila melanogaster. III. Egg insertion behavior.

A genetic analysis of two laboratory strains of Drosophila melanogaster that displayed opposite oviposition tendencies with respect to egg, insertion behavior was performed. In general, the insertion characteristic appears to be dominant over the noninsertion characteristic and is controlled by a polygenic system associated mostly with chromosomes 2 and 3. The results of this study indicate that these genes may be concentrated at the distal end of chromosome 2L and at the distal end of chromosome 3R, and their presence on both of these chromosome regions is needed to approach the full egg insertion effect, suggesting the presence of interaction among genes in these two regions.

Animals↗
PubMed1989

Acute effect of the intranasal administration of salmon calcitonin in osteoporotic women.

Eleven women with primary osteoporosis (mean age, 63.1 years; range, 57-78) received in a random schema: placebo, 200 and 400 IU of salmon calcitonin nasal spray (sCT-NS) during 3 successive days. Total and ionized calcium and phosphate in serum were determined before and 5 h after calcitonin. Total hydroxyproline (THP) and creatinine excretion were measured in urine in three periods of 8 h each after calcitonin administration. The THP excretion after placebo administration showed a circadian rhythm with peak excretion during the night. This rhythm was not altered by sCT-NS administration at 8 a.m. but a sustained diminution of the THP/creatinine excretion was observed. The average decrease after 400 IU of sCT-NS was 9, 16 and 6% during the first, second and third periods of urine collection. Although the average effect of the 200 and 400 IU doses was similar, only the diminution induced by the latter dose on the 24-h period was statistically significant: placebo, 24.8 +/- 2.9; 200 IU, 20.8 +/- 2.9 (P n.s.); 400 IU, 20.1 +/- 2.2 mg/24 h (P less than 0.01). No significant changes were observed on serum except a fall provoked by the 400 IU dose upon ionized calcium (4.44 +/- 0.08 to 4.37 +/- 0.06 mg/dl; P less than 0.05). The administration of 200 or 400 IU of sCT-NS provoked a sustained but moderate decrease of bone resorption on osteoporotic females of a lesser degree than the one observed in a previous study after the parenteral administration of 100 IU.

Administration, Intranasal↗
PubMed1989

Swine cysticercosis treated with praziquantel, a short report.

Swines with cysticercosis are a useful model to study human disease. A multidisciplinary approach was undertaken to study in detail the effect of praziquantel treatment on hosts and parasites. Computerised tomographic scans showed changes in the number and size of parasites in treated pigs. These changes were more apparent in muscle than in brain cysticerci. Neurophysiologic data were normal in cysticercotic pigs before and after drug treatment. An increase in antibody response was seen immediately after treatment regarding the amount of antibodies and number of antigens recognised. A lower number of polyploid lymphocytes was seen after treatment in cysticercotic pigs as compared to untreated pigs. At different times after treatment pigs were humanely euthanised. Oxygen consumption rate of cysticerci decreased after treatment and evagination was abolished. The inflammatory reaction that surrounded parasites increased in number and type of cells. This was more apparent around cysticerci obtained from muscle than from the brain.

Animals↗