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Biomedical subjects

V Lopez

Publications and source records attributed to V Lopez.

At least 37 records · Page 2Linked to original sources
PubMed1996

Short- and long-term effects of ciliary neurotrophic factor on androgen-sensitive motoneurons in the lumbar spinal cord.

Motoneuron death in the spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN) of the lumbar spinal cord is androgen regulated. As a result, many more SNB and DLN motoneurons die in perinatal female rats than in males, whereas treatment of newborn females with androgen results in a permanent sparing of the motoneurons and their target muscles. We previously observed that a neurotrophic molecule, ciliary neurotrophic factor (CNTF), also arrests the death of SNB motoneurons and their target musculature, at least in the short term. The present study compares the short- and long-term consequences of perinatal CNTF treatment on motoneuron number in the SNB, the DLN, and the retrodorsolateral nucleus (RDLN), a motor pool in the lower lumbar cord that does not exhibit hormone-regulated cell death. Female pups were treated with CNTF or vehicle alone from embryonic day 22 through postnatal day 6 (P6). Motoneuron number in the each nucleus was then determined immediately after treatment on P7, or 10 weeks later (P77). CNTF treatment significantly elevated motoneuron number in the SNB and DLN on P7; the volume of SNB target muscles on P7 was also greater in the CNTF-treated group. These effects were transient, however, as motoneuron number and ratings of muscle size were not different in CNTF-and vehicle-treated females on P77. Perinatal CNTF treatment did not alter cell number in the RDLN at either age. The finding that effects of CNTF on SNB and DLN motoneuron number are short lived contrasts with the permanent effects of early androgen treatment, and has implications for molecular models of the actions of androgen and neurotrophic factors on the developing spinal cord.

Age Factors↗
PubMed1996

Developmental expression of calcitriol receptors, 9-kilodalton calcium-binding protein, and calcidiol 24-hydroxylase in human intestine.

Human intestinal mucosa consists of highly active epithelial cells in continual renewal and differentiation processes located at different portions of the villi. The crypt contains abundant replicating cells which, upon reaching the villus tip, acquire their fully differentiated state. Besides its well recognized role in bone cell homeostasis, calcitriol has been attributed a role in cellular differentiation and proliferation in normal leukocytes and myeloid leukemia cells. We have previously documented the presence and the distribution of specific calcitriol receptors in the cells of the small and large intestine from 13-20-wk-old human fetuses and that calcitriol was able to promote human intestinal epithelium proliferation or differentiation, in organ culture, depending upon fetal age. We now show that, whereas transcripts for calcitriol receptors are abundant from duodenum to colon, those for the 9-kD calcium-binding protein are present mainly in the duodenum and the jejunum and to a lesser extent in the ileum and the colon. Transcripts for 25-hydroxycholecalciferol-24-hydroxylase could not be detected in any of the intestine segments despite a prolonged exposition of the gels. Immunofluorescence staining for the 9-kD calcium-binding protein was exclusively observed in the epithelial cells of the small intestine and colon, the subepithelial layers being always negative. The 9-kD calcium-binding protein distribution along the crypt-villus axis appeared as a gradient, increasing from the developing crypt to the tip of the villus in the duodenum, jejunum, and ileum. Based on the present observations and on the fact that calcitriol promotes human fetal proliferation and differentiation, the presence of transcripts for calcitriol receptors and 9-kD calcium-binding protein in the intestinal cell opens interesting possibilities as of their role in the in utero human gut development and the control of colorectal cancers.

Calcium-Binding Proteins↗
PubMed1992

Rational design of substituted tripyrrole peptides that complex with DNA by both selective minor-groove binding and electrostatic interaction with the phosphate backbone.

The structures of the compounds we call 3a, 3b, and 3c-compounds that incorporate (i) the tripyrrole peptide of the minor-groove-binding distamycin class of compounds and (ii) polyamine ligands that extend from the minor groove and can interact with phosphodiester bonds--were arrived at by computer-graphics designing by using the x-ray structure of distamycin A complexed in the minor groove of d(CGCAAATTTGCG)2. Compounds 3a, 3b, and 3c are elaborations of distamycin analog 2, designed for improved stability in solution and easier synthesis and purification, which itself binds weakly to DNA. Compounds 3a, 3b, and 3c have been synthesized, and the interaction of distamycin A, 2, 3a, 3b, and 3c with calf thymus DNA, poly(dA-dT), poly(dG-dC), poly(dI-dC), pBR322 superhelical plasmid DNA, and, in the case of 3b, T4 coliphage DNA have been studied. The following pertinent conclusions can be drawn. Binding of 3a, 3b, and 3c occurs in the minor groove of DNA and, because of favorable electrostatic interaction of diprotonated polyamine side chains and DNA phosphodiester linkages, the tenacity of DNA binding and site specificity of 3a, 3b, and 3c are comparable to that of native distamycin A. 3b has been found to induce changes in the superhelical density of pBR322 plasmid DNA. The study establishes that the central pyrrole N-CH3 substituent of 2 can be replaced by bulky polyamine metal ligands to create any number of compounds that bind into the minor groove at A + T-rich sites and are putative catalysts for the hydrolysis of DNA.

Animals↗
PubMed1991

National survey of clinical and subclinical mastitis in Jamaican dairy herds, 1985-1986.

Between April 1985 and August 1986, 89 Jamaican dairy herds with 10 or more cows were visited, 1,645 lactating cows were examined using the CMT test and 254 composite milk samples collected for bacteriological examination. Widespread management faults were noted, especially of milking machine usage and maintenance and the abuse of antibiotics. Fifty-six per cent of all quarters were found to have CMT scores of one or higher, 0.8% showed clinical mastitis and 3.2% were blind. The most common bacterial pathogen Staphylococcus aureus, was recovered from 31% of sampled cows. The resultant milk loss from clinical and subclinical mastitis was estimated to be 20% of the potential national production.

Animals↗
PubMed1991

The utility of cardiac evaluation in the hemodynamically stable patient with suspected myocardial contusion.

Myocardial contusion following isolated blunt thoracic trauma (BTT) remains a diagnostic and therapeutic dilemma. To identify the presence of cardiac abnormality following BTT, 123 hemodynamically stable patients were prospectively evaluated with serial electrocardiograms (ECG) and cardiac enzymes (total CPK and CPK-MB). Gated cardiac radionuclide angiography (MUGA) scans were performed within 48 hours following admission. Patients included in the study sustained significant thoracic trauma identified by physical findings or mechanism of injury. Sixty-three patients (51%) were identified with either abnormal ECG, or abnormal total CPK, CPK-MB, MUGA scan, or combination of the above. Thirty-seven patients (58.7%) manifested an ECG abnormality defined as ST-segment or T-wave abnormality. Twenty-two patients (34.9%) had total CPK value greater than or equal to 50 International Units (I.U.) or CPK-MB fractions greater than or equal to five per cent. MUGA scan was abnormal (right ventricular ejection fraction less than 40 per cent and/or wall motion abnormality) in 12 patients (19%). Eight patients with MUGA scan abnormality had normal ECG and/or normal total CPK, CPK-MB values. Evaluation of all patients up to six months revealed no mortality, malignant arrhythmias, or cardiac failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Primary tumor of spleen with morphologic features of malignant fibrous histiocytoma. Immunohistochemical evidence for a macrophage origin.

We report a case of primary splenic malignant fibrous histiocytoma that occurred in a 41-year-old man. Adjacent to the tumor there was a large calcified intrasplenic cyst. Despite splenectomy, postoperative radiation, and systemic chemotherapy, the patient died with metastatic tumor 6 months after diagnosis. Electron microscopic analysis of the tumor demonstrated subpopulations of tumor cells with fibroblastic or histiocytic features. Immunoperoxidase studies of frozen tumor tissue showed positive staining of both spindle and histiocytelike tumor cells with a large panel of monoclonal antibodies against antigens associated with the mononuclear phagocyte system. Expression of these antigens by the tumor supports a mononuclear phagocyte origin.

Adult↗
PubMed1977

[Cellular immunity in protein-caloric malnutrition].

In order to have a clearer idea on the relationship between infectious diseases and malnutrition, cellular immunity is studied in 3 to 18 months old malnourished and healthy infants. Nutritional status is evaluated by the food intake the anthropologic measurements and some biological parameters like transferrin. Cellular immunity is investigated by skin tests to tuberculin, monilia, P.H.A. and DNCB. Absolute number of peripheral lymphocytes and percentage of T cells are studied too. The results show that there is a cellular immunity deficiency: frequent non-response to antigens, weak sensitization to DNCB. Some patients have a low percentage of spontaneous rosettes. The transferrin titering is useful to appreciate the nutritional status and the iron therapy opportunity, the prognostic and the immunitary possibilities.

Candida↗
PubMed1975

Defective antibody response to bacteriophage phichi 174 in Down syndrome.

Antibody responses to bacteriophage phichi 174 were studied in 17 institutionalized patients with trisomy 21 and in six mentally retarded control patients with normal karyotype. Primary antibody response was significantly impaired in 11 of the 17 patients. Secondary immune response was normal in one, moderately impaired in seven, and very low in nine patients. Tertiary immunization further differentiated the two groups: those with moderately impaired secondary immune responses developed normal serum titers of predominantly IgG antibody; patients with low secondary immune responses had extemely impaired tertiary immune responses consisting mainly of serum IgM antibody.

Adolescent↗
PubMed1975

The cell growth-promoting factor.

It was recently shown that macromolecular serum proteins [1-3] as well as some of their hydrolyzed products, especially peptides of molecular weight around 5000[4] and even much less[5,6], are able to promote the growth of cells. This paper describes how the serum proteins were separated by salt precipitation and polyacrylamide electrophoresis into various albumin and globulin fractions and their growth-promoting activities ascertained. Subsequently, these macromolecules were treated with alkali, acids or proteolytic enzymes, and the activity of the products obtained was determined. We also isolated growth-promoting peptides from the liver by enzymatic hydrolysis, followed by gel filtration, or by ultrafiltration through Diaflo membranes.

Animals↗