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Biomedical subjects

D Fernandez

Publications and source records attributed to D Fernandez.

At least 37 records · Page 2Linked to original sources
PubMed1993

The time required for the presence of bulls to alter the interval from parturition to resumption of ovarian activity and reproductive performance in first-calf suckled beef cows.

This experiment was designed to determine 1) if exposure of firstcalf suckled beef cows to mature bulls in the first 30 days, after 30 days, or continuously post partum reduces the postpartum anestrous period and 2) if exposure to bulls alters the first service pregnancy rate. Postpartum first-calf suckled crossbred (Angus x Hereford; Hereford x Angus) cows were randomly assigned to be 1) exposed continuously to mature, epididectomized bulls (BE; n = 18); 2) exposed to bulls for the first 30 days post partum (BE/NE; n = 17); 3) exposed to bulls after the first 30 days post partum (NE/BE; n = 16); or not exposed to bulls (NE; n = 18). Blood samples were collected weekly to be assayed for progesterone to determine resumption of ovarian cyclic activity. All the cows were bred for 21 days by AI while under their respective treatment regimens and were then exposed to fertile bulls for an additional 35 days. The postpartum interval to resumption of ovarian cyclic activity did not differ (P>0.10) among the 3 (BE, BE/NE, and NE/BE) treatment groups, but it was 15.4 d shorter (P<0.05) than for cows in the NE group. The overall pregnancy rates did not differ (P>0.10) among the treatment groups. The AI pregnancy rates for the BE/NE and NE/BE treatment groups were higher (P<0.05) than for the NE group. The AI pregnancy rates for the BE and NE treatment groups did not differ (P>0.10). The results showed that all three treatments (BE, BE/NE and NE/BE) similarly decrease the postpartum interval and that exposure to bulls may improve the reproductive performance of first-calf suckled beef cows.

Journal Article↗
PubMed1991

Processing and secretion of human carboxypeptidase E by C6 glioma cells.

Carboxypeptidase E (CPE) catalyses the removal of C-terminal basic amino acids and is implicated in the processing of peptides and hormones in secretory vesicles. The enzyme has been isolated in multiple forms from both soluble and membrane-bound compartments, and has been demonstrated to be co-secreted with peptides from pancreatic and adrenal cells. To address the question regarding the origin of the multiple forms of the enzyme, we have transfected a construct containing the cDNA for human CPE under the control of the murine-sarcoma-virus enhancer and metallothionein promoter into the C6 rat glioma cell line, which itself has extremely low levels of CPE expression. Within transfectants, multiple forms of the enzyme have been detected by Western blotting, and their sizes are comparable with that in pituitary. Fractionation of the intracellular forms of CPE with Triton X-114 at various pH values indicates that the membrane-bound, but not the soluble, form is amphipathic; this difference probably arises from post-translational modification of the enzyme. Interestingly, the secreted enzyme is found to have the amphipathic characteristics of the membrane-bound form. By modification of the cDNA sequence, enzyme lacking N-terminal and C-terminal domains have been expressed: deletion of the 'pro' region of CPE, leading to loss of the signal cleavage site, gives a more hydrophobic but active enzyme which is not efficiently secreted from the cell; deletion of a C-terminal region gives a secreted form of the enzyme which no longer exhibits amphipathic behaviour. Our data indicate that a single mRNA species can give rise to the multiple forms of CPE enzyme that have been identified and that the C6 cells are able to carry out the intracellular processing events to generate these forms.

Amino Acid Sequence↗
PubMed1990

Human carboxypeptidase E. Isolation and characterization of the cDNA, sequence conservation, expression and processing in vitro.

Carboxypeptidase E (CPE), which cleaves C-terminal amino acid residues and is involved in neuropeptide processing, is itself subject to intracellular processing. Human CPE cDNA was isolated and sequence comparisons were made with those of a previously isolated brain cDNA (M1622) encoding rat CPE and of other human carboxypeptidases (M and N). Human (2.5 kb) and rat (2.1 kb) CPE cDNAs approximated to the size of their respective mRNAs; additional sequences were located in putative 5' and 3' untranslated regions of human CPE mRNA. There is 79% sequence similarity between human and rat CPE cDNAs, with greater similarity (89%) over the coding region and short sections of the non-coding sequence. The predicted 476-amino acid-residue sequences of human and rat preproCPEs are highly conserved (96% identity), with lower degree of similarity of the N-terminal signal peptide (76%). Human CPE showed 51% and 43% sequence similarity to human CPN and CPM respectively, with discrete regions of divergence dispersed between the highly conserved mechanistically implicated regions. Antiserum generated from a fusion protein, synthesized in Escherichia coli from constructs of the human cDNA, recognized an approx. 50 kDa membrane protein and a smaller soluble protein in rat and human brain preparations, corresponding to the two forms of native CPE. Human CPE mRNA transcripts directed the synthesis in reticulocyte lysate of a 54 kDa translation product, which in the presence of dog pancreas microsomal membranes was co-translationally processed with cleavage, insertion into membranes and glycosylation. Three processed forms were generated, the largest (56 kDa) and smallest (52 kDa) being equally glycosylated. The membrane association of the processed translation products and of native brain membrane CPE, detected immunologically, was resistant to moderate alkali but not pH 11.5 extraction. These results are consistent with secondary-structure predictions that CPE is a peripheral membrane protein. The dissimilar regions of human carboxypeptidases may provide information on sequences responsible for their different cellular disposition.

Amino Acid Sequence↗
PubMed1990

Charcot-Marie-Tooth disease and nephropathy in a mother and daughter with a review of the literature.

We report a mother-and-child combination of Charcot-Marie-Tooth disease and nephropathy. The mother received a cadaveric renal transplant, and the daughter has heavy proteinuria with normal glomerular filtration rate. There have been 7 single case reports of both disease entities and 1 report of 3 patients which includes the only sib pair. The related literature is reviewed.

Adolescent↗
PubMed1988

Modulation of left ventricular hypertrophy by dietary salt and inhibition of angiotensin converting enzyme.

The interactions of blood pressure, salt intake and angiotensin converting enzyme (ACE) inhibition were investigated in the Dahl salt-sensitive (DS) and salt-resistant (DR) strains of rats. Eight-week-old DS and DR (40 of each) were separately randomized to receive a low- (0.4% NaCl) or a high- (8% NaCl) salt diet for 3 weeks. Thereafter the rats were further separated randomly to receive the ACE inhibitor lisinopril (3-8 mg/kg per day) or no drug treatment for 11 weeks. In untreated DS rats blood pressure rose, paralleled by a higher left ventricular mass (ratio left ventricular weight/body weight) irrespective of salt intake. Lisinopril lowered blood pressure to normotensive levels in all groups except DS rats on a high-salt diet, despite doses of up to 100 mg/kg per day, although there was a significant fall in blood pressure. Lisinopril reduced left ventricular mass significantly on the low- but not on the high-salt diet. Plasma renin activity increased on lisinopril treatment in all groups except DS rats on the high-salt diet. Regression of an increased left ventricular mass by ACE inhibition seemed to be impaired by a high salt intake, even when blood pressure was lowered. Therefore, although for regression of left ventricular hypertrophy, reduction of afterload was the leading factor, this might be adversely affected by a high salt intake.

Aldosterone↗
PubMed1987

Value of isotypic characterization of antibodies to Echinococcus granulosus by enzyme-linked immuno-filtration assay.

In order to establish prognostic criteria for patients with hydatid cysts and to identify functional antigenic components of Echinococcus granulosus 87 sera from 36 patients were studied by enzyme-linked immuno-filtration assay (ELIFA) to characterize the four main classes of specific immunoglobulins and to determine compared immunological profiles (CIP) between samples or subjects. This method uses filtration with labelled antibodies to reveal precipitating systems preformed by immuno-electro-diffusion on cellulose acetate strips. IgG antibodies were demonstrated in the arc 5 and in 11 others bands. Specific IgA, IgE and IgM to Echinococcus granulosus was found in 19%, 53% and 69% respectively of patients with hydatids. The presence of IgM and/or IgE antibodies one year after treatment always correlated with disease. Specific IgA was detected more often in patients with pulmonary cysts. Pre- and post-operative monitoring by CIP-ELIFA proved simple and rapid to perform and of decided prognostic value. Two antigens, corresponding to arc 5 and arc X, were frequently associated with the poly-isotypic immune response.

Animals↗
PubMed1986

Comparative study of calcification in the T6-treated and standard Hancock-I porcine xenografts: experimental study in weanling sheep.

We compared the morphological findings in 15 young sheep in which standard Hancock-I cardiac bioprostheses (7 animals) and T6-processed Hancock-I (8 animals) were implanted in the tricuspid position. The animals were sacrificed at intervals from 8 to 47 weeks after valve replacement. No valvular infection was detected. Six of the 7 untreated valves and 5 of the 8 T6-processed valves in the tricuspid position showed calcific deposits in the radiographic examination. Roentgenograms from all specimens showed a fairly uneven distribution of the mineralization sites with the commissures being the structure most frequently involved. Calcium in the aortic wall was more frequent in the T6-processed group while right coronary leaflet involvement more frequent in the control group. Histologic evaluation confirmed the above data and showed a fibrotic reaction with granulomatous degeneration of the muscular shelf in all valves. Comparison of linear regression lines of the evolution of tissue calcium content with time showed no statistically significant difference between the 2 groups. Under the conditions of this study, the T6-treatment does not reduce the extent of calcification in the Hancock-I porcine xenograft after implantation in the tricuspid position in young sheep.

Animals↗
PubMed1985

Modulation of right and left ventricular wall thicknesses in experimental hypertension.

Enalapril maleate and hydrochlorothiazide were administered over an 8-week period to groups of Dahl salt-sensitive and Dahl salt-resistant rats receiving either a high (8%) or low (0.4%) salt diet. Regional differences of interventricular septal thickness, left ventricular free wall thickness, right ventricular free wall thickness, right ventricular weight/body weight ratio, left ventricular weight/body ratio, and heart weights were determined. For salt-sensitive rats of both diet groups, lowering of blood pressure induced by either drug was associated with a reduction in cardiac weight which was localized to the left ventricle. For salt-resistant rats, irrespective of diet, the associated reduction of cardiac mass induced by enalapril maleate was largely confined to the right ventricle. Regional changes in tissue thickness were, however, not always associated with corresponding changes in tissue mass or blood pressure. These regional modulations appeared to be quite dependent on salt intake and the nature of the antihypertensive drug, for a given animal type, suggesting that pressure afterload is not the only factor in the pathogenesis of left and right ventricular hypertrophy. The responses of the right ventricle were not necessarily the same as those of the left ventricle to identical dietary and drug regimens. In all animal groups, ventricular mass and tissue thickness did not always change in the same sense, suggesting that alterations in the nature and packaging of the cellular constituents may be induced by the combined actions of the dietary salt and antihypertensive medications.

Animals↗
PubMed1984

The reversal of left ventricular hypertrophy with control of blood pressure in experimental hypertension.

The precise mechanisms of hypertensive left ventricular hypertrophy and reversal with antihypertensive drugs are unclear and complex. Enalapril maleate (MK421) and hydrochlorothiazide (HTZ) were used to assess the control of hypertension, and reversal of left ventricular hypertrophy in Dahl sensitive (DS) and Dahl resistant (DR) rats given either a high (8% NaCl), or a low (0.4% NaCl) salt diet. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), left ventricular weight/body weight (LVwt/Bwt) ratio were determined. Both drugs were effective in reducing blood pressure and left ventricular mass in DS rats placed on a high salt diet. For DR rats under the same conditions, only MK421 induced significant lowering of blood pressure. Neither drug caused significant change in ventricular mass. Both DS and DR rats on a low salt diet underwent significant blood pressure reduction with MK421 but not HTZ. Significant regression of the left ventricle was observed only in DS rats treated with MK421. Regression was not observed in DR rats even though MK421 reduced blood pressure to distinctly hypotensive levels. The dissociation of left ventricular mass and blood pressure control observed with both MK421 and HTZ suggests that pressure afterload is not the only factor involved in the pathophysiology of hypertensive cardiac hypertrophy. The mechanisms of anti-hypertensive drug action and salt intake both appear to play a significant if unexplained role.

Animals↗
PubMed1982

Variability of oestrogen and progesterone receptor status between primary breast cancer and nodal metastases: preliminary communication.

The synchronous relationship between oestrogen (ER) and progesterone (PgR) receptor status in primary tumours and their nodal metastases has been analysed in 26 patients. All patients with ER-negative primary tumours were found to have ER-negative axillary nodes but of those with ER-positive tumours only 65% had, correspondingly, all nodes ER-positive. The concentration of ER in the nodes was found to be significantly lower (P less than 0.001) than that in the primary tumour. PgR information was unobtainable in 3 patients. Of the remainder, 75% of those having PgR-negative tumours had all nodes PgR-negative but only 36% of those with PgR-positive tumours had all nodes PgR-positive. PgR levels were found to be generally lower in the axillary nodes but this did not reach statistical significance. The clinical relevance of these findings is discussed.

Axilla↗
PubMed1978

Husband-wife agreement about reproductive goals.

Data from Malaysia on the reproductive goals of husbands and wives are analyzed to determine level of agreement, using new scale measures on preferences for number and sex of children as well as the conventional measure of desired number of children. The level of agreement between husband and wife varies considerably depending on the focus of analysis and the measure of agreement used. Overall aggregate agreement of men and women is high but lower for subgroups of the population, particularly among various ethnic groups. For marital partners, the agreement is much lower, especially on sex preferences. The level observed depends on whether the measure is identity of responses or an index of homogeneity which allows for couple concordance based on chance or common socialization factors. The views about the reproductive goals of one marital partner cannot with confidence be assumed to represent the views of the other.

Age Factors↗
PubMed1977

Techniques of osteosynthesis of pathological fractures due to skeletal metastases.

In using internal fixation in the treatment of fractures due to skeletal metastases the objective is to obtain rapid rehabilitation of the patient. The fixation must therefore be particularly stable and it is consequently often necessary to use acrylic cement. This treatment aims to alleviate pain, to shorten the time spent in hospital, and to restore the patient, as far as possible, to his social background, so alleviating the psychological suffering that complicates such disease states. The elective techniques for the various skeletal segments affected are reported, based on 64 cases of osteosynthesis and 26 prosthetic substitutions.

Bone Neoplasms↗