Biomedical subjects

M Rodriguez

Publications and source records attributed to M Rodriguez.

At least 433 records · Page 24Linked to original sources

PubMed1993

Molecular characterization of South American bovine herpesvirus-1 isolates with monoclonal antibodies and SDS-PAGE.

Antigenic patterns of BHV-1 isolates from Argentina, Chile and Brazil were examined with a panel of monoclonal antibodies (MAbs) generated with BHV-1.1 and BHV-1.3 strains. Among the Argentinian isolates, 7/8 neurological cases showed BHV-1.3 characteristics and 10/12 non-neurological cases from all countries exhibited BHV-1.1/2 pattern. All viral isolates from genital infections showed BHV-1.1/2 characteristics. Chilean isolates exhibited BHV-1.1/2 pattern and one among 3 Brazilian viruses was defined as belonging to BHV-1.3. Results of the characterization using MAbs, were confirmed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of representative isolates. A total correlation was observed between the reactivity with MAbs and the SDS-polyacrylamide analysis. Based on the data presented, it is concluded that the type 1.3, most frequently obtained from the brain of neurological cases, is present in Argentina and Brazil and coexists with BHV-1.1/2.

Animals↗

PubMed1993

Endotoxin-induced pulmonary dysfunction is prevented by C1-esterase inhibitor.

In septic shock, hypotension, disseminated intravascular coagulation, and neutrophil activation are related to the activation of the blood coagulation contact system. This study evaluates in dogs the effect of the C1-esterase inhibitor (C1-INH), a main inhibitor of the blood coagulation contact system, on the cardiovascular and respiratory dysfunction associated with endotoxic shock. Two groups were included: controls, which received Escherichia coli endotoxin, and a C1-INH group in which C1-INH was infused before E. coli endotoxin administration. In both groups, endotoxin produced hypodynamic shock; however, the decrease in the systolic index and the ventricular systolic work indexes were greater in controls than the C1-INH group. In controls, the arterial O2 partial pressure decreased by 30% and the alveolo-arterial O2 difference increased by 625%, these parameters remained unchanged in the C1-INH group. Hypoxemia was associated with increased intrapulmonary shunt, decreased blood coagulation contact factors, and decreased C3c. In contrast, C1-INH administration prevented endotoxin-induced hypoxemia, the increase in intrapulmonary shunt, and the decrease in blood coagulation contact factors. This study shows that, in dogs with endotoxic shock, pulmonary dysfunction is associated with an activation of the blood coagulation contact phase system. An inhibition of this system by C1-INH prevented the hypoxemia induced by endotoxic shock.

Animals↗

PubMed1993

Trauma and multiple sclerosis: a population-based cohort study from Olmsted County, Minnesota.

Utilizing the Olmsted County, Minnesota, population-based records-linkage resource at Mayo Clinic, we identified an incidence and a prevalence cohort with multiple sclerosis (MS), a head injury cohort, and a lumbar disk surgery cohort to evaluate the association between mechanical trauma and MS onset or exacerbation. The MS cohorts consisted of 225 incidence cases (1905 to 1991) and 164 prevalence cases (December 1, 1991) of definite MS in the population of Olmsted County. We assessed the effect of mechanical trauma in the form of spinal injury or extremity fracture with regard to precipitation of MS or exacerbation of an existing neurologic deficit. Fifty-four episodes of trauma, as defined, occurred among 39 MS prevalence cases; most occurred 10 years or more after the onset of disease and were associated with existing MS-related disability. We compared the final disability status of the groups with and without trauma. We found no correlation between the occurrence of peripheral fractures and the onset of MS, exacerbation of MS, or final disability due to MS in the prevalence cohort. In a cohort of 819 head injury cases from the Olmsted County population, none developed MS within 6 months of the trauma. In a lumber disk surgery cohort of 942 local residents, there were five with MS, but onset of MS had preceded the spinal surgery in four of the five. Thus, we found no association of head injury and spinal disk surgery with onset of MS.

Cohort Studies↗

PubMed1993

Cabergoline in Parkinson's disease: long-term follow-up.

We treated 36 patients with motor fluctuations and dyskinesias on chronic levodopa therapy with cabergoline (CBG) once a day for a mean period of 14.2 +/- 5.8 months. There was a significant increase in the "on" hours and a reduction in "off-period" dystonia. Ten patients continued to show a marked improvement after 28.3 months of treatment (mean dose, 11.3 +/- 4.5 mg). In 23 patients, increased dyskinesias (daily CBG dose, 11 +/- 4.3 mg) had complicated the positive effect after 17.2 +/- 4.8 months. Three patients (daily CBG dose, 14.3 mg) were therapeutic failures, and administration of CBG was stopped. Side effects leading to CBG discontinuation were visual hallucinations (n = 5), heart failure (n = 5), and nausea and vomiting (n = 1). Plasma CBG levels, measured in seven patients taking 3, 5, or 7 mg daily (po), showed fairly stable concentrations throughout the 24 hours. We concluded that CBG is an efficient dopamine agonist that can provide continuous dopaminergic stimulation when taken orally once a day.

Adult↗

PubMed1993

Plasmapheresis in acute episodes of fulminant CNS inflammatory demyelination.

We present six patients with acute fulminant episodes of CNS inflammatory demyelination who responded to therapeutic plasmapheresis after failing a course of high-dose methylprednisolone administered IV. Neurologic improvement occurred in three of the patients following the second plasmapheresis. Dramatic improvement in motor function (four patients) and language (two patients) began within 2 to 14 days and persisted during the 6 to 35 months (mean, 15 months) of follow-up. Results of this uncontrolled study suggest that plasmapheresis in the absence of other immunosuppressive drugs may have a role in the treatment of severe episodes of inflammatory demyelination in a select subset of MS patients.

Adult↗

PubMed1993

Sex differences in EEG coherence in normal children.

The idea that sex differences in the execution of different mental tasks mean a different cerebral organization met contradictory results. Sex differences in brain electrical activity were reported by various authors. The EEG coherences show functional and anatomical interrelation, so they may reveal differences in brain organization. This paper tries to demonstrate how sex differences are manifested in EEG coherences, in 42 right-handed control children, 18 girls and 24 boys, aged 7.6 to 13.3. Since the effect of age is high on EEG measurements, regression against age was calculated and eliminated. The Z-transformed coherence values were compared by Student's t-test. The results obtained showed that girls had higher right intrahemispheric coherence values than boys in all bands. These sex differences were more numerous in the theta band. The interhemispheric differences were slight and girls had higher coherences in all bands except for the alpha band, where boys had higher interhemispheric coherence than girls. These results show slight but consistent differences in the functional organization of the right hemisphere by sex and reveal the necessity to elaborate separated EEG norms for boys and girls.

Adolescent↗

PubMed1993

[Existence of an antidiuretic reflex in the sheep during food intake].

The effect of eating on glomerular filtration and urine flow was studied in the sheep. Glomerular filtration rate was reduced during eating but the effect disappeared when food was removed. Urine flow showed the same evolution but, after ingestion was stopped, it returned later than glomerular filtration to control values. During the early phases of feed ingestion, an anticipatory anti-diuretic reflex therefore exists. The anti-diuretic response is probably dependent on a simultaneous decrease in glomerular filtration. But the temporary delay between the recovery of glomerular filtration and urine flow after feed is removed suggests the existence of a second factor responsible for the lowered urine flow.

Animals↗

PubMed1993

Fibrinolytic activity during hemodialysis: a biocompatibility-related phenomenon.

According to recent reports, fibrinolytic activity may be enhanced during hemodialysis. The aim of this work was to study the fibrinolytic activity in uremic patients, and to evaluate the effect of membrane biocompatibility on the fibrinolytic system during hemodialysis. Tissue plasminogen activator (t-PA), t-PA antigen, plasminogen activator-inhibitor (PAI), plasminogen (PL) and alpha-2-antiplasmin (AP) were measured in 10 uremic patients on maintenance hemodialysis treated sequentially with Cuprophane and polyacrylonitrile (AN69) membranes. Blood samples were obtained before and at 15, 60 and 120 minutes after the initiation of dialysis. Blood was also collected from 20 healthy individuals who served as controls. During cuprophane dialysis, t-PA increased significantly at 60 minutes (14.8 vs. 8.4 IU/ml, P < 0.05) and at 120 minutes (13.8 P < 0.01). This was accompanied by an increase in t-PA antigen, which was significant at 15 (5.1 vs. 13.1 ng/ml), 60 (15.2) and 120 (9.6) minutes (P < 0.05) of dialysis. However, during AN69 dialysis t-PA and t-PA antigen plasma levels remained stable. No significant changes were observed in PL, AP or PAI during hemodialysis with either membrane. In conclusion, hemodialysis enhances fibrinolytic activity, which is likely the result of t-PA Ag release. Therefore, this phenomenon seems to be closely related to dialysis membrane biocompatibility.

Adult↗

PubMed1993

Current status of the diagnosis and control of African horse sickness.

African horse sickness (AHS) is an infectious, non-contagious, highly fatal viral disease of Equidae, transmitted by arthropod vectors of the genus Culicoides, and endemic in Africa south and east of the Sahara. The disease is caused by a virus of the Reoviridae family, genus Orbivirus, and 9 serotypes have been recognized. Recent outbreaks of AHS in the Iberian peninsula and Northern Africa emphasize the need for accurate diagnosis and rapid implementation of control measures. In this paper, the epizootiological factors, clinical signs and necropsy findings of AHS are discussed, and an updated review of diagnostic laboratory methods together with a description of the main control measures is given.

Africa↗

PubMed1993

[Magnetic resonance tomography (MRT) of the knee joint: meniscus, cruciate ligaments and hyaline cartilage].

The use of MRT for diagnosing injury to the meniscus, the cruciate ligaments and hyaline cartilage was evaluated retrospectively in 82 knee joints without any knowledge of operative findings. In 49 cases the results were verified by arthroscopy and in 33 cases by arthrotomy. Sensitivity, specificity and diagnostic accuracy of MRT for meniscus lesions was 73.9%, 96.9%, and 94.6%. Corresponding values for lesions of the anterior cruciate ligament were 88.9%, 96.6%, and 94.7%, and for lesions of the hyaline cartilage 62.6%, 96.1%, and 87.9%, respectively. In addition to its high specificity, MRT proved accurate in excluding lesions of the meniscus (97.1%) of the anterior cruciate ligament (96.6%) and of hyaline cartilage (88.8%). A negative finding on MRT therefore makes the presence of a lesion of the meniscus, cruciate ligaments of cartilage unlikely. In such cases one is justified in delaying the use of arthroscopy or arthrotomy.

Adolescent↗

PubMed1993

Effect of aluminium on the development of hyperparathyroidism and bone disease in the azotaemic rat.

Aluminium toxicity in dialysis patients is associated with a relative parathyroid hormone (PTH) deficiency as well as osteomalacia. In-vitro studies of parathyroid cells have shown that aluminium inhibits PTH secretion. However, only limited data are available on how aluminium affects the development of hyperparathyroidism in the azotaemic animal. Four groups of azotaemic rats were studied; in each group, renal failure was induced by a two-stage 5/6 nephrectomy, after which rats were studied for 40 days. In three groups hyperparathyroidism was stimulated by the use of a high phosphorus (1.2%) diet (HPD). The four groups were (1) HPD; (2) HPD + high-dose aluminium (HDAL)--1.5 mg of aluminium was administered intraperitoneally (IP) 5 days per week; (3) HPD + low-dose aluminium (LDAL)--0.5 mg of aluminium was administered IP 5 days per week; and (4) moderate phosphorus (0.6%) diet (MPD); the MPD group was used to control hyperparathyroidism and thus provide a comparison of PTH levels and azotaemic bone disease. After 40 days, the serum PTH level was higher (P < 0.05) in the HPD + HDAL group (37 +/- 2 pmol/l) than the HPD, HPD + LDAL, and MPD groups (24 +/- 3, 28 +/- 4, and 6 +/- 1 pmol/l respectively). The correlation between serum PTH and calcium, serum PTH and phosphorus, and serum calcium and phosphorus was significant for the four groups (P < 0.02); however, the relationship between serum PTH and calcium, and between serum calcium and phosphorus was altered in the HPD + HDAL group (serum aluminium 30.8 +/- 2 mumol/l). Aluminium administration induced a decrease (P < 0.05) in the bone formation rate and the adjusted apposition rate, and an increase (P < 0.05) in osteoid volume and the mineralization lag time. Despite aluminium administration, diet-induced hyperparathyroidism resulted in an increase (P < 0.05) in the osteoblast surface. In conclusion, in the azotaemic rat (1) aluminium did not slow the development nor decrease the magnitude of hyperparathyroidism; (2) aluminium appeared to alter the relationship between serum PTH and calcium, and between serum calcium and phosphorus; (3) hyperparathyroidism changed the expression of aluminium-induced bone disease and may afford the bone some protection against the toxic effects of aluminium.

Aluminum↗

PubMed1993

The effect of dialysate osmolarity on ultrafiltration and vascular refilling rate.

The osmotic gradient is the main driving force for ultrafiltration (UF) in continuous ambulatory peritoneal dialysis (CAPD). Depending on glucose absorption, its changes over a period of time could influence the plasma refilling rate. The aim of this study was to evaluate the influence of changes in the plasma refilling rate obtained by dialysates of different osmolalities upon the rate of UF. Stable CAPD patients were studied twice during a 4-hour exchange 2 weeks apart with dialysate containing 1.5% and 4.25% glucose, respectively. UF was estimated by the autologous hemoglobin dilution method every 30 minutes. Hematocrit and colloidosmotic pressure (COP) decrease when using 1.5% glucose dialysate, reflecting a rise in plasma water mediated by the plasma refilling rate. This water shift is greater than the osmotic gradient generated between peritoneal and intravascular compartments as reflected by a low UF rate. However, when the osmotic gradient increases by means of 4.25% glucose dialysate, the plasma refilling rate is efficiently counter-balanced by UF.

Diabetes Mellitus, Type 1↗

PubMed1992

JMV 449: a pseudopeptide analogue of neurotensin-(8-13) with highly potent and long-lasting hypothermic and analgesic effects in the mouse.

We recently reported that H-Lys psi (CH2NH)Lys-Pro-Tyr-Ile-Leu-OH (JMV 449), a pseudopeptide analogue of neurotensin-(8-13) with a reduced CH2NH bond in position 8-9, was about 3 times more potent than neurotensin in binding to mouse brain membranes and in contracting the guinea-pig ileum, and was markedly more resistant to degradation than neurotensin when exposed to rat brain membranes. In the present study, we compared the time courses and dose-response relationships for the ability of i.c.v. injected neurotensin and JMV 449 to elicit hypothermia and analgesia (tail-flick test) in the mouse. The results show that the pseudopeptide analogue behaved as a highly potent and long-lasting neurotensin agonist in these two in vivo bioassays. The analogue should prove very useful for studying the effects of chronic neurotensin receptor stimulation in vitro and in vivo.

Amino Acid Sequence↗

PubMed1992

Effects of thiorphan, bestatin and a novel metallopeptidase inhibitor JMV 390-1 on the recovery of neurotensin and neuromedin N released from mouse hypothalamus.

The effects of the endopeptidase 24.11 ('enkephalinase') inhibitor thiorphan, the aminopeptidase inhibitor bestatin and a novel metallopeptidase inhibitor JMV 390-1 on the K(+)-evoked release of immunoreactive neurotensin and neuromedin N (iNT and iNN) from mouse hypothalamic slices were examined. (JMV 390-1 inhibits several metallopeptidases including endopeptidases 24.11, 24.15 and 24.16, and aminopeptidase N equipotently with Ki values around 50 nM.) Thiorphan increased the recovery of released iNT nearly 2-fold and had no effect on iNN. Bestatin produced a 4-fold increase in iNN recovery and was inactive on iNT. Finally, iNT and iNN recoveries were increased up to 4- and 5-fold, respectively, by JMV 390-1. These results show that in the mouse hypothalamus endopeptidase 24.11 participates with other metalloendopeptidases to the degradation of endogenously released NT while endogenously released NN is principally degraded by aminopeptidase(s).

Amino Acid Sequence↗

PubMed1992

Waterborne transmission of epidemic cholera in Trujillo, Peru: lessons for a continent at risk.

The epidemic of cholera that began in Peru in January, 1991, marked the first such epidemic in South America this century. Subsequently, over 533,000 cases and 4700 deaths have been reported from nineteen countries in that hemisphere. We investigated the epidemic in Trujillo, the second largest city in Peru. Trujillo's water supply was unchlorinated and water contamination was common. Suspect cholera cases were defined as persons presenting to a health facility with acute diarrhoea between Feb 1, and March 31, 1991. We studied a cohort of 150 patients who had been admitted to hospital and conducted a matched case-control study with 46 cases and 65 symptom-free and serologically uninfected controls; we also carried out a water quality study. By March 31, 1991, 16,400 cases of suspected cholera (attack rate 2.6%), 6673 hospital admissions, and 71 deaths (case-fatality rate 0.4%) had been reported in the province of Trujillo. 79% of stool cultures of patients with diarrhoea presenting to a single hospital yielded Vibrio cholerae O1. In the case-control study, drinking unboiled water (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.3-7.3), drinking water from a household water storage container in which hands had been introduced into the water (4.2, 1.2-14.9), and going to a fiesta (social event) (3.6, 1.1-11.1) were associated with illness. The water quality study showed progressive contamination during distribution and storage in the home: faecal coliform counts were highest in water from household storage containers and lowest in city well water. V cholerae O1, biotype El Tor, serotype Inaba, was isolated from three city water samples. Cholera control measures in Trujillo should focus on treatment of water and prevention of contamination during distribution and in the home. Trujillo's water and sanitation problems are common in South America; similar control measures are needed throughout the continent to prevent spread of epidemic cholera.

Adolescent↗

PubMed1992

NADH-activated cell-free transfer between Golgi apparatus and plasma membranes of rat liver.

This report concerns development of a cell-free system from rat liver to study transport of membrane constituents from the Golgi apparatus to the plasma membrane. Highly purified Golgi apparatus as donor and a mixture of sheets and vesicles as plasma membrane acceptor fractions were combined to analyze requirements for lipid and protein transport. In the reconstituted system, the Golgi apparatus donor was in suspension. To measure transfer, membrane constituents of the donor membranes were radiolabeled with [3H]acetate (lipids) or [3H]leucine (proteins). The plasma membrane vesicles were used as the acceptor and were unlabeled and immobilized on nitrocellulose for ease of recovery and analysis. The reconstituted cell-free transfer was dependent on temperature, but even at 37 degrees C, the amount of transfer did not increase with added ATP, was not specific for any particular membrane fraction or subfraction nor was it facilitated by cytosol. ATP was without effect both in the presence or absence of a cytosolic fraction capable of the support of cell-free transfer in other systems. In contrast to results with ATP, NADH added to the reconstituted system resulted in an increased amount of transfer. A further increase in transfer was obtained with NADH plus a mixture of ascorbate and dehydroascorbate to generate ascorbate free radical. The transfer of labeled membrane constituents from the Golgi apparatus to the plasma membrane supported by NADH plus ascorbate radical was stimulated by a cytosol fraction enriched in less than 10 kDa components. This was without effect in the absence of NADH/ascorbate radical or with ATP as the energy source. Specific transfer was inhibited by both N-ethylmaleimide and GTP gamma S. The findings point to the possibility of redox activities associated with the trans region of the Golgi apparatus as potentially involved in the transport of membrane vesicles from the Golgi apparatus to the cytoplasmic surface of the plasma membrane.

Animals↗

PubMed1992

Role of T cell receptor V beta genes in Theiler's virus-induced demyelination of mice.

Intracerebral infection of certain strains of mice with Theiler's virus results in chronic immune-mediated demyelination in spinal cord. We used mouse mutants with deletion of the V beta class of TCR genes to examine the role of TCR genes in this demyelinating disease which is similar to multiple sclerosis. Quantitative analysis of spinal cord lesions demonstrated a markedly increased number and extent of demyelinated lesions in persistently infected RIII S/J mice which have a massive deletion of the TCR V beta-chain (V beta 5.2, V beta 8.3, V beta 5.1, V beta 8.2, V beta 5.3, V beta 8.1, V beta 13, V beta 12, V beta 11, V beta 9, V beta 6, V beta 15, V beta 17) compared with B10.RIII mice which are of identical MHC haplotype (H-2r) but have normal complement of V beta TCR genes. In contrast, infection of C57L (H-2b) or C57BR (H-2k) mice which have deletion of the V beta TCR genes (V beta 5.2, V beta 8.3, V beta 5.1, V beta 8.2, V beta 5.3, V beta 8.1, V beta 13, V beta 12, V beta 11, and V beta 9) resulted in few demyelinating lesions. Genetic segregation analysis of (B10.RIII x RIII S/J) x RIII S/J backcrossed mice and (B10.RIII x RIII S/J) F2 mice demonstrated correlation of increased susceptibility to demyelination with deletion of TCR V beta genes. The increase in number of demyelinating lesions correlated with increase in number of virus-Ag+ cells in spinal cord. These experiments provide strong evidence that the structural diversity at the TCR beta-complex can influence susceptibility to virus-induced demyelination.

Animals↗

PubMed1992

The major Thiobacillus ferrooxidans outer membrane protein forms low conductance ion channels in planar lipid bilayers.

A protein isolated and purified from the outer membrane of the acidophilic, chemolithotrophic bacterium, Thiobacillus ferrooxidans with an oligomeric molecular weight of 90,000 Da (p90) was incorporated into phosphatidylethanolamine planar lipid bilayers. The protein formed slightly anionic channels in KCl solutions, with a conductance of 25 pS in 100 mM KCl. The current-voltage relationship was linear between +/- 60 mV, and the conductance was a saturating function of the salt concentration. These channels fluctuated from a single open to closed state at low potentials, but present flickering activity at higher potentials.

Bacterial Outer Membrane Proteins↗