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Biomedical subjects

M Rodriguez

Publications and source records attributed to M Rodriguez.

At least 577 records · Page 32Linked to original sources
PubMed1989

Treatment of encephalomyocarditis virus-induced central nervous system demyelination with monoclonal anti-T-cell antibodies.

Infection of BALB/c mice with the M variant of encephalomyocarditis virus resulted in the development of a paralytic syndrome in 7 to 10 days. The paralysis was maximal during the period of viral clearance; most of the animals recovered from the initial deficit and showed no delayed recurrences. Pathologically, the white matter of brain and spinal cord showed well-demarcated areas of perivascular cuffing, demyelination, and, during recovery, remyelination by oligodendrocytes--all suggestive of postinfectious encephalomyelitis. Depletion of either the CD4 or CD8 subset of T cells in vivo with the appropriate monoclonal antibody, GK1.5 or 2.43, respectively, administered one day (24 h) prior to infection was sufficient to limit the development of the paralytic syndrome by 79% (GK1.5) and 82% (2.43).

Animals↗
PubMed1989

The prevalence of the Wernicke-Korsakoff syndrome in Sydney, Australia: a prospective necropsy study.

In a prospective necropsy study, the prevalence of the Wernicke-Korsakoff syndrome (WKS) in Sydney, Australia was 2.1% of adults over the age of 15 years. The population studied encompassed a wide spectrum of socio-economic and cultural backgrounds. Abuse of alcohol appeared to be the major predisposing factor to the development of the WKS in cases which were adequately documented. This high prevalence rate is in line with other clinical and pathological Australian studies and provides additional support for the idea of prevention of the WKS by the use of thiamin supplements in the Australian diet in flour, bread and perhaps alcoholic beverages.

Adolescent↗
PubMed1989

Catheter-induced aortic thrombus masquerading as coarctation of the aorta.

The placement of an umbilical artery catheter is firmly established as an essential technique in the care of ill neonates. This simple procedure involves well recognized risks. Thrombotic complications are frequently seen with umbilical artery catheter (UAC) placement. The occurrence, however, of an aortic thrombus presenting as classical aortic coarctation has not been reported previously. This report describes two infants with classical symptomatology of coarctation of the aorta who were found instead to have aortic thrombus formation in association with umbilical artery catheter placement.

Aortic Coarctation↗
PubMed1989

The coexistence of Taenia solium cysticerci and the pig: role of the antigen B.

A review of data on the antigen B of Taenia solium (AgB) is presented. The biochemical, immunological and physiological properties of AgB are discussed in the context of the host-parasite relationship. It is proposed that AgB facilitates survival of cysticerci by impairing augmentation of the host inflammatory response through the inhibition of the classical pathway of the complement cascade. In this way, AgB not only allows evasion of the host immune attack but also decreases the host-parasite confrontation, facilitating their coexistence.

Animals↗
PubMed1989

Detection of bovine herpesvirus type 1 via an immunoperoxidase method, using monoclonal antibodies.

The sensitivity and specificity of the immunoperoxidase technique, using monoclonal antibodies, for the detection of bovine herpesvirus type 1 (BHV-1) was assessed and compared with viral isolation methods. In this study, BHV-1 antigens were detected in impression smears of brain obtained from calves in which BHV-1 was isolated. False-positive results were not observed after double-blind examination. Preliminary identification of isolates as antigenic variants was possible by use of 3 monoclonal antibodies reactive with neurotropic and/or pneumotropic strains of BHV-1. Results were consistent with previous work in which characterization was performed by use of immunofluorescense and ELISA. The immunoperoxidase technique, using monoclonal antibodies, was determined to be specific and sensitive, compared with viral isolation, for the diagnosis of BHV-1 encephalitis. In addition, it has operative advantages in that the assay does not require tissue culture facilities, and results can be obtained within hours after specimens are obtained.

Animals↗
PubMed1989

[Comparative study of Uromiron and 38% Lipiodol in sialography].

A comparative study was undertaken to assess the properties of uromiron and lipiodol 38%, which are used as radiopaque materials in sialographic techniques, on 25 young adult outpatients of both sexes that were seen at the Dental School, University of Chile, Santiago. It was found that, although the radiopaque properties of uromiron were less than lipiodol 38%, the can be improved by increasing the amount of material injected into the duct system of the salivary glands. Likewise, uromiron exhibited a proper biological tolerance and a rapid emptying time, therefore the use of uromiron in sialographic techniques seems to be a proper alternative to lipiodol 38%.

Adult↗
PubMed1989

Intrathecal somatostatin in cat and mouse studies on pain, motor behavior, and histopathology.

Effects of intrathecal (i.t.) somatostatin (SST) on nociception, motor function, and spinal cord pathology were evaluated in cats and mice. Cats chronically implanted with i.t. lumbar catheters received either a single injection of 2 mg SST i.t. (group I, N = 4), four repetitive injections on consecutive days of 2 mg SST i.t. (group II, N = 4) or saline i.t. (group III, N = 2). No analgesic effects were observed following single or repeated SST injections as evaluated by the skin twitch response. However, significant impairment of hind leg motor function ranging from unbalanced gait to paralysis was observed following the first SST i.t. injection. Histological examination of spinal cords six days after the first SST injection in group II showed multiple pyknotic neurons in all cats. Some cats showed focal demyelination in the posterior column of the spinal cord white matter. Mice received a single percutaneous injection of 50 micrograms SST i.t. (group I, N = 7), 5 micrograms SST i.t. (group II, N = 3), or saline i.t., (group III, N = 5). No analgesic effects were observed in groups II and III as evaluated by the hot plate (HP) and tail flick (TF) tests. Injection of 50 micrograms SST i.t. (group I) caused reversible flaccid hind leg paralysis in all mice and concomitant increases in HP and TF latencies. Histologic examination revealed focal demyelination in the spinal cord in three out of seven mice in this group. Present data substantiate neurotoxic effects of i.t. SST and lack of behaviorally defined antinociception at innocuous dosages.

Animals↗
PubMed1989

Refractory potassium repletion due to cisplatin-induced magnesium depletion.

Cisplatin is a common cause of hypomagnesemia and hypokalemia due to renal magnesium (Mg) and potassium (K) losses. Magnesium plays an important role in the maintenance of intracellular K. An unrecognized and untreated Mg depletion can lead to a refractory K repletion. We describe two patients with hypomagnesemia-associated refractory hypokalemia following cisplatin following cisplatin therapy. Potassium supplementation failed to replace the K deficit. Profound hypokalemia persisted until hypomagnesemia was recognized and corrected. In neither patient was the concurrent hypomagnesemia recognized until the 11th and 9th hospital days. These two cases demonstrated the association of a refractory K repletion and an Mg deficiency. Thus, both serum K ion and Mg levels should routinely be assessed in patients who require cisplatin therapy.

Adult↗
PubMed1988

Successful therapy of Theiler's virus-induced demyelination (DA strain) with monoclonal anti-Lyt-2 antibody.

The effects of therapy with mAb to T cell subsets were studied in mice with Theiler's murine encephalomyelitis virus-induced demyelination. mAb GK1.5 (directed at class II-restricted T cells) and mAb 2.43 (directed at class I-restricted T cells) depleted the appropriate subset of T cells in lymph nodes, spleens, and peripheral blood for 6 to 8 wk after a single i.p. injection of 1 mg of purified mAb. Early treatment with mAb GK1.5 (days -1, 0, and +1 relative to virus injection) resulted in death, encephalitis, and increased demyelination in the majority of animals tested. Treatment with mAb 2.43 resulted in less meningeal inflammation and fewer demyelinating lesions in the spinal cord, irrespective of whether the mAb was given early or after demyelinating disease was established (days 15, 16, and 17). Beneficial response to mAb therapy did not correlate with titers of virus isolated from the central nervous system or serum. These results indicate an important role of class II-restricted T cells during early disease in preventing overwhelming encephalitis; class I-restricted T cells may be critical during demyelination.

Animals↗
PubMed1988

Structural mutation affecting intracellular transport and cell surface expression of murine class II molecules.

We have selected Ia variants from the Ia+ (H-2d) M12.4.1 B cell lymphoma that are negative on the cell surface for one or both Ia isotypes. The molecular analysis of two such independently selected cell lines, M12.A2 and M12.C3, is reported here. This analysis revealed that the genes encoding Ad beta (M12.A2) and Ed beta (M12.C3) contained identical single-nucleotide transitions that resulted in the substitution of Ser (mutant) for Asn (wild-type) at residue 82/83 of the extracellular NH2-terminal (membrane distal) beta 1 domain. This conservative substitution caused a cytoplasmic accumulation of I-A or I-E molecules in the respective cell line although predicted secondary-structure analysis suggests a minimal effect on protein conformation. Thus, the mutation appears to have either created a negative signal that stops transport or eliminated a positive signal that is required for transport and targeting to the cell surface.

Amino Acid Sequence↗
PubMed1988

Immunoglobulins and complement in demyelination induced in mice by Theiler's virus.

Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) produces chronic demyelination and persistent infection in the central nervous system (CNS) of susceptible SJL mice. This series of experiments examined the contribution of humoral immunity and C to myelin destruction. As in multiple sclerosis, mice persistently infected with TMEV had elevated levels of IgG and oligoclonal bands in the cerebrospinal fluid (CSF). Immunoblot studies revealed that even in animals exhibiting profound demyelination, IgG in the serum and CSF was directed primarily at virus antigen rather than at normal myelin components. Inflammatory cells positive for Ig were distributed mainly around blood vessels, but occasionally they infiltrated the spinal cord parenchyma. Rare examples of myelin sheaths positive for IgG were found by immunoelectron microscopy in spinal cord sections from infected mice; the third component of complement (C3) was commonly found in the walls of CNS blood vessels but not on myelin. Neither serum nor CSF IgG from infected mice bound to myelin sheaths or other CNS components in sections of normal syngeneic spinal cord. There were significantly more demyelinating lesions in infected mice depleted of C components with cobra venom factor. These data do not support a humoral autoimmune basis for the CNS demyelination that occurs in association with persistent TMEV infection. However, the humoral immune response directed at TMEV antigens may either limit virus spread or promote virus persistence.

Animals↗
PubMed1988

The tubulin genes of Trypanosoma cruzi.

The organization of the alpha- and beta-tubulin genes in the genome of Trypanosoma cruzi have been analysed by Southern blotting using tubulin probes derived from Trypanosoma brucei. The tubulin array appears to be more complex in this organism than in other members of the same family. Some tubulin genes are tightly clustered in an alternating (alpha-beta)n array with a basic repeat unit length of 4.3 kb. However, other pairs of alternating alpha- and beta-tubulin sequences appear to be physically separated from the basic group. This finding indicates that the tubulin gene cluster present in T. cruzi is less perfectly conserved than in T. brucei. T. (Herpetosoma) rangeli is similar to T. (Schizotrypanum) cruzi in its tubulin gene organization whereas most of these genes are tandemly clustered in the genome of T. (Trypanozoon) evansi, with a basic repeat unit length of 3.6 kb as previously described for T. (Trypanozoon) brucei. Two overlapping recombinant clones containing T. cruzi tubulin sequences have been isolated from a genomic cosmid library of T. cruzi epimastigotes using the T. brucei tubulin probes. Partial sequencing of the T. cruzi beta-tubulin gene has confirmed its identity and shows more than 70% homology with the sea urchin, chicken and T. b. rhodesiense beta-tubulin reported gene sequences. Analysis of tubulin gene organization through the parasite life cycle does not show evidence of major rearrangements within the repeat unit. Several T. cruzi strains and cloned lines whilst sharing the 4.3-kb tubulin repeat unit, exhibited very variable tubulin gene organization with tubulin probes. These striking differences in the organization of this structural gene among T. cruzi strains and cloned lines suggest that the heterogeneity previously reported in parasite populations may be related to a very dynamic, diploid genome.

Animals↗
PubMed1988

Periodic sharp waves in baclofen-induced encephalopathy.

Acute encephalopathy and an abnormal electroencephalogram with a periodic sharp wave pattern developed in a 58-year-old woman shortly after she received a few doses of baclofen. The clinical and electroencephalographic abnormalities improved promptly after the medication was discontinued.

Baclofen↗
PubMed1988

Dose-response effect of sublingual captopril in hypertensive crises.

Forty-one patients, presenting in the Emergency Service of the Hospital General y Clinico, Tenerife, with symptoms of hypertensive crisis and supine diastolic blood pressure (DBP) greater than 120 mm Hg, were studied. They received 12.5 mg of sublingual captopril and 30 minutes later, if diastolic blood pressure (DBP) was not 100 mm Hg or less, the same dose was repeated by the same route. Supine systolic blood pressure (SBP), DBP and heart rate (HR) were monitored at 0, 5, 10, 15, 30, 45, 60, and 120 minutes after each administration of captopril. In 27 patients (66%) had a satisfactory response (DBP less than or equal to 100 mm Hg), after a single dose, less than 30 minutes after administration, which persisted at 120 minutes. In 14, a second administration was necessary after 30 minutes, and a satisfactory response to the second dose, defined again as DBP reaching values of 100 mm Hg or less, was achieved in 12 of them (29% of the total group). In two patients (5% of total) no full response was obtained. The observed pattern of response suggests that a sublingual dose of 25 mg of captopril is the minimum effective dose, but it is also possible that administration of 12.5 mg of sublingual captopril at 10 to 15 minute intervals, perhaps up to a maximum dose of 37.5 mg, might be considered as an alternative treatment in hypertensive crises.

Administration, Sublingual↗
PubMed1988

Study of histamine release induced by acute administration of antitumor agents in dogs.

The effects of eight antitumoral drugs known to cause anaphylactoid side effects in clinical use were studied in dogs. Blood pressure, heart rate, and blood and plasma histamine levels were monitored. L-asparaginase, methotrexate, 5-fluorouracil, bleomycin, and cisplatin had no effect on these parameters. Doxorubicin, Vehem (teniposide), and Vepeside (etoposide) induced hypotension, tachycardia, and a rise in histamine levels. In the cases of Vehem and Vepeside, the excipient (respectively, cremophor EL and tween 80) induced the same effects. These agents, like elliptinium, which had been previously studied, induce nonspecific histamine release--unlike the other drugs studied. The mechanism of clinically observed anaphylactoid side effects is discussed in the light of these findings.

Anaphylaxis↗
PubMed1988

Theiler's virus-associated antigens on the surfaces of cultured glial cells.

Infection of the central nervous system by Theiler's murine encephalomyelitis virus (TMEV), a picornavirus, produces chronic demyelinating disease in susceptible mice. In this immunoelectron microscopic study of TMEV infection of neonatal mouse brain cells in culture, TMEV antigen was found on the surfaces of infected oligodendrocytes and astrocytes by labeling with hyperimmune serum from TMEV-infected mice or with rabbit antiserum to purified inactivated DA strain TMEV. Brain-derived macrophages had no TMEV-specific antigen on their surfaces and were not able to maintain productive TMEV infection, even though TMEV antigen was present in the cytoplasm. The presence of TMEV antigens on the surfaces of oligodendrocytes (myelin-producing cells) was unexpected because picornaviruses are nonenveloped viruses and do not bud from cell surfaces. The finding is consistent with the hypothesis that demyelination follows damage of infected oligodendrocytes by immune cells or immunoglobulins that recognize surface virus antigen.

Animals↗
PubMed1988

Cholecystokinin suppresses food intake in cats: structure-activity characterization.

Our experimental models in this study were cats fitted with gastric fistulae. Intravenous infusion of sulfated CCK 8 and nonsulfated Boc CCK 7 inhibited both sham-feeding and feeding in fasted cats. The threshold dose (1.2 pmol/kg.hr) required for inhibition of sham-feeding was identical to that required to inhibit feeding in the same animals. However, the gastric secretory studies indicated that this dose was 90 times lower than the threshold dose stimulating gastric acid secretion (109 pmol/kg.hr). In nonfasted animals, sulfated CCK 8 and nonsulfated Boc CCK 7 (219 and 875 pmol/kg.hr) are both capable of decreasing the food intake at different intervals following the infusion with no significant effect on daily food intake. Our findings clearly show that there is no difference in the sensitivity of CCK's ability to inhibit sham-feeding and feeding, suggesting that CCK's suppressive effect on food intake does not solely involve gastric distension mechanisms. In contrast to gastric acid secretion, the sulfate group is not a "restrictive" factor for peripherally-induced CCK satiety.

Animals↗