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Biomedical subjects

J M Ortiz

Publications and source records attributed to J M Ortiz.

At least 19 recordsLinked to original sources
PubMed1998

Growth arrest of Schizosaccharomyces pombe following overexpression of mouse type 1 protein phosphatases.

Three mouse genes encoding type 1 protein phosphatase isotypes alpha, gamma and delta were expressed in Schizosaccharomyces pombe cells under the control of the regulatable promoter nmt1. In the repressed state, basal expression of mouse genes was able to rescue the S. pombe mutant dis2-11. An integrated mouse gene could not, however, genetically complement S. pombe double mutants carrying disrupted dis2 and sds21 protein phosphatase genes. Overexpression of any of the three mouse protein phosphatase1 isotypes produced growth arrest and loss of viability in wild-type S. pombe cells. Overexpressing cells showed defects in chromosome distribution and in the formation of septa. These defects are characteristic of the expression of the mammalian protein phosphatases in S. pombe, since they are not observed after overexpression of endogenous S. pombe type 1 protein phosphatases. Overexpression of a truncated version of isotype delta, which lacked protein phosphatase activity, reproduced most of the characteristics of the lethal phenotype. We conclude that the lethal effect may be due to interactions with essential cell cycle proteins.

Animals↗
PubMed1997

Influence of different systems of feeding in the appearance of cryptosporidiosis in goat kids.

This study evaluated how different systems of feeding may influence the appearance, maintenance, or both of cryptosporidial infection. Animals reared with natural lactation, a traditional artificial feeding system, and a variety of the latter were studied for oocysts in feces. The diagnosis was made by examination of fecal smears stained with auramine-O. Morbidity and mortality were high, particularly in farms with bad hygienic conditions and natural feeding systems. The traditional artificial feeding system is not enough to reduce the presence of parasites. Isolation of newborns at birth and colostrum administration with a feeding bottle, obtained in the most aseptic conditions possible, seems to be an effective prophylactic method for cryptosporidiosis control.

Animals↗
PubMed1995

Down-regulation of c-Myc and Max genes is associated to inhibition of protein phosphatase 2A in K562 human leukemia cells.

Treatment of the human myeloid leukemia K562 cells with the protein phosphatase inhibitors okadaic acid or calyculin A resulted in down-regulation of both c-myc and max genes at the mRNA and protein levels. The extent of the down-regulation was similar for both genes and was dependent on the dose and on the treatment time. Interestingly, c-myc and max down-regulation was concomitant with apoptosis induced by okadaic acid and calyculin A in K562 cells. The expression of c-myc and max returned to control levels after the removal of okadaic acid from the media, although apoptosis was irreversible. These effects were observed at okadaic acid concentrations (15 nM) that inhibited the activity of protein phosphatase type 2A but not of phosphatase type 1. We conclude that the inhibition of protein phosphatase 2A is associated to decreased levels of c-Myc/Max heterodimers in K562 cells.

Apoptosis↗
PubMed1995

Scleritis, uveitis, and glaucoma in a patient with rheumatic fever.

PURPOSE: To determine the origin of scleritis, uveitis, and glaucoma in a boy with fever, sore throat, joint pains, and malaise. METHODS: The patient underwent extensive hematologic, serologic, rheumatologic, and radiologic examinations. RESULTS: The patient recovered after extensive medical therapy. He met the Jones criteria for the diagnosis of acute rheumatic fever and had an increased result for antistreptolysin O antibody titer. CONCLUSIONS: Antistreptococcal antibody testing is helpful in diagnosing rheumatic fever as a cause of scleritis, uveitis, and glaucoma.

Acute Disease↗
PubMed1993

Elevated serum thyrotropin [TSH] levels in critically ill patients with acquired immunodeficiency syndrome (AIDS).

STUDY OBJECTIVE: To determine thyrotropin (TSH) reserve in critically ill patients with Acquired Immunodeficiency Syndrome (AIDS). DESIGN: Prospective longitudinal. SETTING: Six hundred (600) bed municipal hospital serving a poor neighborhood in New York City with a high incidence of AIDS mainly from intravenous drug abuse. PATIENTS AND METHODS: Twelve (12) patients with AIDS, who were in the Intensive Care Unit or critically ill on medical wards, were evaluated consecutively with baseline thyroid function tests and serum thyrotropin (TSH) response to thyroid releasing hormone testing. RESULTS: 66.7% of patients had elevated TSH levels. All patients had low triiodothyronine (T3), six patients had low thyroxine (T4) levels. RESULTS: (cont'd). Six patients met the criteria for hypothyroidism. Two patients met the criteria for subclinical hypothyroidism. CONCLUSION: Elevated TSH levels and hypothyroidism are common in our critically ill population with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Downregulation of hepatic albumin mRNA in response to induced hypercholesterolemia in rabbits.

Albumin gene expression was studied in rabbits fed on a cholesterol-rich diet for up to 16 weeks. Livers from experimental animals showed extensive lipid deposition. Hepatic albumin mRNA abundance decreased along the treatment to very low levels after 16 weeks. An 8-fold decrease in the rate of transcription of this gene was also detected. This downregulation of albumin gene expression cannot be attributed to a general impairment of RNA synthesis, as expression of other liver-specific and housekeeping genes did not vary significantly. There was a decrease in ascitic fluid albumin levels after 10 weeks, although serum albumin levels remained unchanged throughout the treatment. Our results are discussed in view of the relationship of albumin levels with hypercholesterolemia.

Animals↗
PubMed1992

Foam cells from aorta and spleen overexpress apolipoprotein E in the absence of hypercholesterolemia.

We have studied Apo E expression in atherosclerotic lesions and spleens in rabbits after a cholesterol-rich diet is discontinued and plasma cholesterol levels return to normal values. After 16 weeks, foam cells are still present in the atherosclerotic lesions and Apo E expression persists restricted solely to the lesion as ascertained by in situ RNA hybridization and northern blot. Apo E expression is induced in spleens of hypercholesterolemic rabbits. However Apo E mRNA levels decrease in this organ parallel to the disappearance of lipid loaded macrophages. These results of in vivo studies indicate that Apo E overexpression in foam cells does not depend on high serum cholesterol levels, but is a characteristic of macrophages that have acquired the foam cell phenotype.

Animals↗
PubMed1992

Characterization and nucleotide sequence of the oriT-traM-finP region of the IncFVII plasmid pSU233.

By hybridizing the IncFVII haemolytic plasmid pSU233 with a probe containing the origin of transfer of the IncFII plasmid R1, we isolated a 1.9 kb BglII fragment containing at least the origin of transfer (oriT), and the genes traM and finP. Functional complementation analysis of deletion derivatives was used to map the origin of transfer. We also determined the nucleotide sequence of traM and finP. Comparison with similar regions of several plasmids, also belonging to the Rep-FIIA family, revelaed that pSU233 resembles the F plasmid by very close. The homology is not evenly distributed along this region, but clustered into homologous regions (TraZb-oriT, TraMb-oriT and traM separated by non-homologous regions (TraYb-oriT, finP). This organization resembles that reported for the replication region and also suggests evolution by exchange of modules. In addition, the nucleotide sequence of finP is different from those previously described for other IncF plasmids and constitutes a new allele, which we have denominated allele VI.

Amino Acid Sequence↗
PubMed1992

Hypercholesterolemia induces differential expression of rabbit apolipoprotein A and C genes.

We have compared steady-state mRNA levels of apolipoproteins AI, AII, AIV, CI, CII and CIII in liver and small intestine of rabbits fed on a cholesterol-rich diet for up to 16 weeks. Apolipoprotein (apo) AIV mRNA was detected in both liver and small intestine, while apo AII was not detected in either organ. Apo CI, apo CII and apo CIII were expressed only in liver and apo AI mRNA was detected only in small intestine. In small intestine, apo AIV and apo AI mRNA levels increased to a maximum at the 4th and 12th week of treatment, respectively. In liver there was a parallel increase in the mRNA levels of apo AIV, apo CI, apo CII and apo CIII, with maximum levels after 4 weeks of treatment. A 3-fold increase was found in apo CII and apo CIII hepatic transcription rates between hypercholesterolemic and control rabbits after 4 weeks of treatment, no longer detectable after 8 weeks. However, no changes were found in apo AIV and apo CI transcription rates. Changes in apolipoprotein mRNA levels were accompanied by changes in plasma lipoprotein levels. Overall, these changes correlate well with the variations detected in the expression of the different apolipoprotein genes. Our results indicate that dietary cholesterol plays an important role in the regulation of these genes and that this regulation is tissue dependent.

Animals↗
PubMed1991

Isolation and evolutionary analysis of a RepFVIB replicon of the plasmid pSU212.

We have isolated at least two different replication regions from pSU401, a Tn802 insertion derivative of the IncFVI plasmid pSU212. One of the replication regions (RepFVIB) is highly homologous to the RepFIIA replicon of IncFII plasmids, and thus belongs to the RepFIIA family. We have also cloned the incompatibility determinant (incFVI) and the copy number control gene (cop) from RepFVIB and determined their nucleotide sequences. The analysis of the sequences supports the idea of a modular evolution of RepFIIA plasmids.

Amino Acid Sequence↗
PubMed1991

Conjunctival synthetic and nonsynthetic fiber granulomas.

Synthetic and nonsynthetic fiber granulomas can be easily diagnosed and treated. This is a case of a child who had a granulomatous inflammation surrounding a filamentous foreign body that was removed and identified by simple histopathologic techniques. The pathologic findings are remarkably similar to the few case reports in the literature. Accurate reporting of these findings may reveal a greater incidence of synthetic and nonsynthetic fiber granulomas.

Child, Preschool↗