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Biomedical subjects

M Sanchez

Publications and source records attributed to M Sanchez.

At least 163 records · Page 9Linked to original sources
PubMed1990

Intestinal absorption of arachidonic acid in experimental azotemia.

The effect of renal failure (RF) on intestinal absorption of dietary fatty acids is not known. We studied the intestinal absorption of arachidonic acid (AA) in rats with experimental short-term (2 weeks post-subtotal nephrectomy) and long-term (5-6 weeks post-subtotal nephrectomy) RF. The results were compared with those obtained in sham-operated animals on liberal food intake (NL) and in those pair-fed (PF) with the respective RF groups. In vivo perfusion and in vitro incubation experiments were performed at a wide range of AA concentrations. The rates of AA transport determined both in vivo and in vitro were significantly lower in the short-term RF group than those found in the NL controls and the PF animals who showed comparable values. In contrast animals with long-term RF exhibited an increased rate of AA transport as compared with the respective controls. The observed changes in the transport rates appeared to parallel directional changes in mucosal mass which was reduced in animals with short-term RF and restored in those with long-term RF.

Animals↗
PubMed1990

The spectrum of syphilis in patients with human immunodeficiency virus infection.

Five patients infected with the human immunodeficiency virus (HIV) with unusual manifestations of syphilis are reported. The high prevalence of HIV seropositivity among our patients with syphilis, the rapid progression to tertiary disease, the increased severity of the clinical manifestations, inappropriate antibody responses to infection, relapse without reexposure despite "adequate" treatment, and lack of response to penicillin therapy have been observed in these and in other patients. Data are presented to explain these unusual observations.

Adult↗
PubMed1990

Hypereosinophilic syndrome with unusual cutaneous manifestations in two men with HIV infection.

We report two men with human immunodeficiency virus infection who had unusual cutaneous manifestations of hypereosinophilic syndrome, exfoliative erythroderma, and linear flagellate plaques. In the first patient the cutaneous disease was the initial manifestation, and in the second the skin was the only organ affected. We also describe a favorable response to systemic corticosteroids and to psoralen with UVA phototherapy in one patient.

Adrenal Cortex Hormones↗
PubMed1990

Mideyelid entropion.

A distinct entity of entropion involving the middle portion of the lower eyelids is presented. This condition is not related to any local or systemic disorder and does not progress to entropion of the entire lower eyelid. Segmental atrophy of the lower lid tarsus is present.

Aged↗
PubMed1990

Plasma and CSF levels of albendazole and praziquantel in patients with neurocysticercosis.

Albendazole or praziquantel were measured in plasma and cerebrospinal fluid (CSF) in 29 patients with neurocysticercosis. Mean levels of albendazole in plasma were 0.918 microgram/ml and in CSF were 0.392 microgram/ml and levels of praziquantel were 1.640 micrograms/ml in plasma and 0.398 microgram/ml in CSF, after doses of 15 and 50 mg/kg, respectively. Drug concentrations in CSF were 43% for albendazole and 24% for praziquantel. The drug levels obtained for both drugs showed ample individual variations that were not related to age, sex, presence of inflammation in the subarachnoid space, or therapeutic effectiveness; such variations seem to be due to individual differences in pharmacokinetics. Both drugs were effective and the doses currently used of each drug seem to be optimal for therapy of neurocysticercosis.

Adolescent↗
PubMed1990

Extinction and activation of the thyroglobulin promoter in hybrids of differentiated and transformed thyroid cells.

Thyroglobulin gene expression was repressed in a rat thyroid cell line transformed with Kirsten murine sarcoma virus. Expression of a dominant selectable marker driven by the thyroglobulin promoter was also inhibited. Somatic cell hybridization of transformed and differentiated thyroid cells resulted in extinction of thyroglobulin gene expression. When transformed cells carrying a dominant selectable marker driven by the thyroglobulin promoter were fused to differentiated cells and expression of this marker was selected, we obtained stable hybrid cell lines expressing both the endogenous and the exogenous thyroglobulin promoters. Although the expression of v-ras remained unchanged compared with expression in the parental transformed cells, transformation was suppressed in the hybrid cell lines. The other thyroid differentiation markers, iodide uptake and thyroid-stimulating hormone-dependent growth, were inhibited in all the hybrids tested. We show that activity of the thyroglobulin promoter correlates with the presence of a thyroid nuclear factor that binds the promoter at position -60 from the transcription start site. Loss of this factor accompanies the extinction of thyroglobulin gene expression in hybrids selected for expression of a non-thyroid-specific promoter.

Animals↗
PubMed1990

Traumatic rupture of aorta. Diagnosis by Doppler echocardiography.

Traumatic rupture of aorta is a serious complication in accidents, mainly road accidents, with a high mortality unless an immediate diagnosis and surgical correction is made. A case of traumatic rupture of the aorta shown in the acute phase by Doppler-echocardiography is reported. This technique can be of great value in the study of patients with thoracic trauma who do not show clear signs of aortic rupture which require urgent aortography.

Accidents, Traffic↗
PubMed1990

Sex, drugs, and HIV infection in a New York City hospital outpatient population.

Persons attending outpatient clinics at Bellevue Hospital Center in Manhattan, New York City were invited to be tested for antibodies to human immunodeficiency virus (HIV). In pretest counseling, males were asked if they had injected nonprescription drugs or engaged in sex with other men since January 1, 1977; if so, they were asked not to participate and were referred elsewhere for testing. Face-to-face interviews and HIV testing were completed for 1,119 subjects with no prior indication of HIV seropositivity. Willingness to participate in the study was significantly greater among women than men and among younger than older persons. After exclusion of two subjects with indeterminate HIV serology, seroprevalence was 6.3% (70/1,117) overall, 7.1% (26/368) among men, and 5.9% (44/749) among women. HIV seropositivity among female i.v. drug users was 37% (27/74). Among heterosexuals without other HIV risk factors, estimated seroprevalences were 2.7% (25/924) overall, 3.3% (10/305) among males, and 2.4% (15/619) among females. Among heterosexual men, the data suggested associations of HIV seropositivity with sex with prostitutes and sex with numerous partners. Multiple logistic regression analysis indicated that significant predictors of HIV infection among women were a history of sexual contact with a male intravenous drug user, recent last use of intravenous drugs, and long duration of residence in New York City. Sexual intercourse with persons from AIDS risk groups was reported by 11% of men and 18% of women. The modal method of birth control reported by both men and women was "no method".

Adult↗
PubMed1990

Quality control of perfusion: monitoring venous blood oxygen tension to prevent hypoxic acidosis.

The long-held belief that venous oxygen tension mirrored tissue oxygen tension became suspect in the 1960s when new instrumentation consistently showed that tissue oxygen tension was 10 to 30 torr less than venous oxygen tension. Moreover, a countercurrent of oxygen exchange between terminal arteries and veins was shown to exist. Despite this conflict in scientific theory, however, monitoring venous oxygen tension as a means to control hypothermic cardiopulmonary bypass has been repeatedly urged, since myocardial acidosis is clearly extremely detrimental. This study of the relationship between venous oxygen tension during hypothermic bypass and a concurrent increment in lactacidemia yields strong objective evidence to support the use of on-line venous oxygen tension monitoring to guide perfusion. In a random series of 36 patients, venous blood samples were drawn at five preselected intervals during operation and were analyzed for pH, carbon dioxide tension, oxygen tension, lactic acid, hematocrit, and base excess. Analysis of the data revealed that venous pH and base excess showed no correlation to venous oxygen tension. However, lactic acid showed a strong correlation with venous oxygen tension, with a correlation coefficient of 0.4338 at a confidence level of p less than 0.0001. If the patients were divided into three clinically pertinent groups based on the lowest venous oxygen tension recorded, a strong relationship between venous oxygen tension and lactic acid emerged. If the lowest measurement of venous oxygen tension was greater than 35 mm Hg (group A), the mean rise in lactic acid was only 0.12 microns/ml. If the lowest measurement was between 30 and 34 mm Hg (group B), the mean rise was 0.64 microns/ml. Whereas, if any venous oxygen tension value fell below 30 mm Hg (group C), the mean rise in lactic acid was 2.56 microns/ml. Analysis of variance showed that group C values were significantly different from groups A and B values (p less than 0.0002). A scientific hypothesis relating venous oxygen tension to adequate tissue oxygenation is proposed. Use of venous oxygen tension monitoring with the goal to maintain the level above 35 mm Hg is strongly supported by this study.

Acidosis, Lactic↗
PubMed1989

Reactivation of thyroglobulin gene expression in transformed thyroid cells by 5-azacytidine.

Transformed rat thyroid cells fail to express thyroglobulin. Cells transformed with a Kirsten murine sarcoma virus carrying a temperature-sensitive ras allele lose their transformation phenotype when shifted to the nonpermissive (39 degrees C) temperature. The thyroglobulin promoter, however, remains inactive. Similarly, transfection of these cells with a thyroglobulin promoter fused to a neomycin resistance reporter gene does not produce clones resistant to G418. Treatment of the transfected cells with the DNA demethylating agent 5-azacytidine reactivates the thyroglobulin promoter and yields stable G418-resistant clones. We show that thyroglobulin promoter activity is correlated with the presence of a thyroid-specific nuclear factor, TgTF1. TgTF1 cannot be detected in transformed cells but reappears after treatment with 5-azacytidine at 39 degrees C. Restoration of Ras activity at 33 degrees C leads to the rapid loss of TgTF1 and G418 resistance.

Animals↗
PubMed1989

Substance P receptors in the human spinal cord: decrease in amyotrophic lateral sclerosis.

The distribution of substance P receptors was examined by autoradiography at all levels of the human postmortem spinal cord using the ligand [125I]Bolton-Hunter substance P. Adjacent sections were used to localize substance P-like immunoreactivity by a radioimmunohistochemical technique. In the control spinal cord substance P-like immunoreactivity was found to be highly concentrated in the superficial layers of the dorsal horn, intermediolateral cell columns and lamina X, while lower levels of immunoreactivity were observed in other areas of the grey matter of the spinal cord. In contrast, high densities of substance P binding sites were localized not only to the substantia gelatinosa of the dorsal horn but also to other regions of the grey matter of the spinal cord, particularly in the area of the preganglionic sympathetic neurons in the intermediolateral cell column and in the region of the somatic motor neurons of the ventral horn. In 5 cases of amyotrophic lateral sclerosis we found a marked reduction of substance P binding, especially in the ventral horn associated with the loss of motor neurons. These results suggest a postsynaptic localization of substance P receptors to the motor neurons of the ventral horn in the human spinal cord and a role for substance P in the function of motor neurons.

Adult↗
PubMed1989

Purification and properties of two succinic semialdehyde dehydrogenases from Klebsiella pneumoniae.

Two forms of succinic semialdehyde dehydrogenase have been isolated in Klebsiella pneumoniae M5a1. The two enzymes could be separated by filtration on Sephacryl S-300 and their apparent molecular weights were approx. 275,000 and 300,000. The large enzyme is specific for NADP. The smaller enzyme, which is induced by growth on 3-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid and gamma-aminobutyrate, has been purified to 96% homogeneity by affinity chromatography. The NAD-linked succinic semialdehyde dehydrogenase was able to use NADP as cofactor. Its induction is coordinated with 3- and 4-hydroxylase, the enzymes which initiate degradation of 3- and 4-hydroxyphenylacetic acid. The NAD-linked form is also induced by exogenous succinic semialdehyde. The large enzyme is specific for NADP and has been isolated from a defective mutant which lacked the activity of the NAD-linked succinic semialdehyde dehydrogenase. Activity and stability conditions and true K m values for substrates and cosubstrates of the two enzymes were determined. Some aspects of the induction of the NAD-linked enzyme participating in the metabolism of 4-hydroxyphenylacetic and gamma-aminobutyrate were studied.

Enzyme Induction↗
PubMed1989

[A neuromusculoarticular reeducation technic from pieziography].

Once defined the neutral equilibrium space in edentulous patients, we examined the importance of phonation for the determination of this space. This allows us to highlight the interest of recording mandibular pressures as a procedure of neuro-muscular rehabilitation. On the basis of recording pressures, we developed an original method of neuro-muscular rehabilitation for complete edentulous patients.

Dental Impression Technique↗
PubMed1989

A continuous line of chicken embryo cells derived from a chondrocyte culture infected with RSV.

A continuous line of chicken embryo cells was derived from a culture of chondrocytes infected with Rous sarcoma virus (RSV). These cells, designated as NA101, have reduced serum requirements and are able to grow in a semisolid medium. NA101 cells show the same phenotype as freshly RSV infected chondrocyte cultures, i.e. synthesis of fibronectin and type I collagen, elongated bipolar shape and absence of tumorigenicity following grafting onto the chorioallantoic membrane of embryonated duck eggs; thus they appear to be distinct from transformed fibroblasts. Neither NA101 cells nor freshly infected chondrocyte cultures synthesize type II or type X collagen, which are the differentiation markers of normal chicken chondrocytes in culture.

Animals↗