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Biomedical subjects

J R Martins

Publications and source records attributed to J R Martins.

At least 19 recordsLinked to original sources
PubMed2006

Ticks (Ixodidae) on humans in South America.

Twenty eight species of Ixodidae have been found on man in South America (21 Amblyomma, 1 Boophilus, 2 Dermacentor, 2 Haemaphysalis, 1 Ixodes and 1 Rhipicephalus species). Most of them are rarely found on man. However, three species frequently parasitize humans in restricted areas of Argentina (A. neumanni reported from 46 localities), Uruguay (A. triste from 21 sites) and Argentina-Brazil (A. parvum from 27 localities). The most widespread ticks are A. cajennense (134 localities in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela), A. ovale (37 localities in Argentina, Brazil, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela) and A. oblongoguttatum (28 sites in Brazil, Colombia, French Guiana, Guyana, Suriname and Venezuela). Amblyomma aureolatum (18 localities in Argentina, Brazil, French Guiana and Paraguay), A. cajennense, and A. triste are vectors of rickettsioses to man in South America. A better understanding of the respective roles of these and other tick species in transmitting pathogens to humans will require further local investigations. Amblyomma ticks should be the main subjects of these studies followed by species of Boophilus, Dermacentor, Haemaphysalis and Rhipicephalus species. In contrast with North America, Europe and Asia, ticks of the genus Ixodes do not appear to be major players in transmitting diseases to human. Indeed, there is only one record of an Ixodes collected while feeding on man for all South America.

Animals↗
PubMed2005

Serum laminin, type IV collagen and hyaluronan as fibrosis markers in non-alcoholic fatty liver disease.

Hepatic fibrosis in patients with non-alcoholic fatty liver disease is associated with progression of the disease. In the present study, we analyzed the discriminative ability of serum laminin, type IV collagen and hyaluronan levels to predict the presence of fibrosis in these patients. In this preliminary report, we studied 30 overweight patients divided into two groups according to the absence (group I, N = 19) or presence (group II, N = 11) of fibrosis in a liver biopsy. Triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltranspeptidade, hyaluronan (noncompetitive fluoroassay), type IV collagen, and laminin (ELISA) were determined. Group II presented significantly higher mean laminin, hyaluronan, type IV collagen, and aspartate aminotransferase values, which were due to the correlation between these parameters and the stage of fibrosis in the biopsy (Spearman's correlation coefficient, rS = 0.65, 0.62, 0.53, and 0.49, respectively). Analysis of the ROC curve showed that laminin values >282 ng/ml were those with the best diagnostic performance, with 87% accuracy. Association of laminin with type IV collagen showed improvement in the positive predictive value (100%), but with reduction in diagnostic sensitivity (64%). When compared with the criteria of Ratziu et al. for the diagnosis of septal fibrosis, laminin values presented a better diagnostic accuracy (83 vs 70%). Determination of extracellular matrix components in serum, especially of laminin, may identify patients with non-alcoholic fatty liver disease and fibrosis and these components may be used as indicators for liver biopsy in these patients.

Adult↗
PubMed2003

Amblyomma aureolatum (Pallas, 1772) and Amblyomma ovale Koch, 1844 (Acari: Ixodidae): hosts, distribution and 16S rDNA sequences.

DNA sequences of Amblyomma aureolatum (Pallas, 1772) and Amblyomma ovale Koch, 1844 were obtained to determine genetic differences between these tick species. Collections of these species are discussed in relation to distribution and hosts. Seven ticks collections (four from Brazil, one from Argentina, one from Uruguay and one from USA) house a total of 1272 A. aureolatum (224 males, 251 females, 223 nymphs and 574 larvae) and 1164 A. ovale (535 males, 556 females, 66 nymphs and 7 larvae). The length of the sequenced mitochondrial 16S rRNA gene fragment for A. aureolatum was 370bp and for A. ovale was 373bp. The DNA sequence analysis showed a 13.1% difference between the two species. Apart from one male A. ovale found on a toad, all adult ticks were found on mammals. The majority of adult specimens of both tick species were removed from Carnivora (96.1 and 84.3% of A. aureolatum and A. ovale, respectively), especially from dogs (53.1% of A. aureolatum, and 46.4% of A. ovale). Collections on wild Canidae were higher for A. aureolatum (23.3%) than for A. ovale (7.1%). On the other hand, collections of A. ovale adults on wild Felidae were higher (18.3%) than findings of A. aureolatum (9.2%). The contribution of other mammalian orders as hosts for adults of A. aureolatum and A. ovale was irrelevant, with the exception of Perissodactyla because Tapiridae contributed with 13.0% of the total number of A. ovale adults. Adults of both tick species have been found occasionally on domestic hosts (apart of the dog) and humans. Most immature stages of A. aureolatum were found on Passeriformes birds, while rodents and carnivores were the most common hosts for nymphs and larvae of A. ovale. A. aureolatum has been found restricted to the Neotropical region, covering the eastern area of South America from Uruguay to Surinam, including northeastern Argentina, eastern Paraguay, southeastern Brazil and French Guiana. A. ovale showed a distribution that covers the Neotropical region from central-northern Argentina throughout the Neotropics into the Nearctic region of Mexico with a few records from the USA, also with collection sites in Paraguay, Bolivia, most Brazilian states, Peru, Ecuador, French Guiana, Surinam, Guyana, Trinidad & Tobago, Venezuela, Colombia, Panama, Costa Rica, Nicaragua, Belize, Guatemala and several states of Mexico.

Animals↗
PubMed2002

Partial strategic tick control within a herd of European breed cattle in the state of Rio Grande do Sul, southern Brazil.

A trial is described, in the state of Rio Grande do Sul, southern Brazil, as one of a series suggested to investigate the effects of strategic but selective acaricide treatments of cattle within herds against Boophilus microplus. They are aimed at considering the repercussions of farmer attempts at immediate reductions in acaricide costs and the potential for creation of 'refugia' of untreated ticks. Half (Group 1) of a small experimental herd of European breed heifers were treated strategically against ticks, three times during the late spring-early summer and twice during autumn (southern hemisphere), with an injectable avermectin endectocide, designed to act directly against the first and third generations of parasitic B. microplus per 'cattle tick year' at this site, respectively. The consequent levels of infestations on all of the member cattle in their common pasture were monitored. Group 1 showed low to zero tick counts during the 28-day treatment interval periods and up to ca. 14 days after the last of such a series. Treated cattle, however, became re-infested outside of these periods and to levels that would be considered as unacceptable by farmers in the state. The untreated cattle (Group 2) showed infestations at generally higher levels, than their contemporaries, within and outside of the treatment periods. There were thus ample sources of larvae in the pasture, derived principally from falling, untreated engorged female ticks, re-infesting both the treated and untreated cattle. Advantages of maintaining chemically untreated cattle ticks within a herd, compared to their disadvantages as contaminants to classical strategic control procedures, merit re-evaluation, especially in relation to the recent, world-wide resurgence of acaricide resistance in B. microplus.

Animals↗
PubMed2001

Toxicity of cypermethrin and diazinon to Haematobia irritans (Diptera: Muscidae) in its American southern range.

Synthetic pyrethroids are considered currently less effective than organophosphate insecticides for controlling Haematobia irritans on cattle in its American southern range. To test the validity of this hypothesis, horn fly populations from 95 cattle herds in central-northern Argentina and southern Brazil were evaluated to determine 50% lethal concentrations (LC(50)) to cypermethrin and diazinon, respectively. Horn flies were exposed to filter papers and glass vials treated with cypermethrin and diazinon, respectively, and LC(50) values were determined using probit analysis. Two and 78 fly populations showed LC(50) values indicating susceptibility and resistance to cypermethrin, respectively, in comparison to historical LC(50) values obtained when the horn fly populations were susceptible to cypermethrin. Five fly populations had an undetermined resistance status to cypermethrin. The diazinon tests showed no obvious indications of H. irritans resistance. Thirty nine percent of farmers still rely on pyrethroids to control horn fly populations on cattle which represents a decreasing proportion from a few years ago when horn fly control was carried out using pyrethroids almost exclusively. Organophosphates could provide control for horn flies resistant to pyrethroids; however, the reliance on chemicals alone to control H. irritans is not considered a proper approach for the future.

Animals↗
PubMed2000

Remaining small bowel length: association with catheter sepsis in patients receiving home total parenteral nutrition: evidence of bacterial translocation.

Patients with short bowel syndrome (SBS) receiving total parenteral nutrition (TPN) have a high incidence of catheter-related sepsis, one of its major complications. The aim of this study was to correlate the length of remaining small bowel (RSB) with septic episodes related to the central venous catheter in a group of patients with severe SBS with home TPN. The length of the RSB (<50 cm or > or = 50 cm) was related to the frequency of catheter sepsis, time until the first episode, and the agents responsible in eight SBS patients receiving home TPN. There were 13 episodes of catheter infection (0.88 per patient-year). The group with a shorter RSB length (five patients) presented 1.3 to 2.76 infections/year and 2 to 9 months until the first episode, compared to 0 to 0.75 infections/ year (p = 0.0357) and 11 to 65 months until the first episode (p = 0.0332) in the group with the longer RSB. In the first group, the agents isolated were Enterobacteriae (Enterobacter sp., Klebsiella sp., Pseudomonas sp., and Proteus sp.) in eight episodes and Candida sp. in one. In the latter sepsis was caused by Staphylococcus sp. in three episodes and Pseudomonas sp. in one. Therefore patients with remaining small bowel shorter than 50 cm have a higher frequency of catheter-related sepsis, particularly by enteric microorganisms. This might be an evidence of the occurrence of bacterial translocation and its role in the pathogenesis of catheter-related sepsis in patients with an extremely short RSB receiving home TPN.

Adult↗
PubMed2000

Patients with head and neck tumors excrete a chondroitin sulfate with a low degree of sulfation: a new tool for diagnosis and follow-up of cancer therapy.

The chondroitin sulfate excreted in the urine of 10 patients with cancer of the head and neck and 27 healthy subjects was analyzed. The disaccharide products formed from chondroitin sulfate excreted by these 10 patients by action of chondroitinase ABC show a significant (P < 0.0001) relative increase of nonsulfated disaccharide (35.6% +/- 5.7%) when compared with the nonsulfated disaccharide (10.0% +/- 0.9%) present in the chondroitin sulfate of 27 healthy subjects. In 6 patients the structure of the excreted compound was analyzed up to 4 months after surgery. After removal of the cancer, the percent amounts of the nonsulfated disaccharide tend to approach the values found for the chondroitin sulfate of healthy subjects. A significant (P < 0.0001) change in the ratio of urinary chondroitin sulfate and heparan sulfate and a decrease in the electrophoretic migration of chondroitin sulfate were also observed. All of the patients with head and neck cancer analyzed so far have shown this structural anomaly of urinary chondroitin sulfate. This assay may be useful in the diagnosis and follow-up of cancer therapy.

Adult↗
PubMed2000

Babesiosis (Babesia bovis) stability in unstable environments.

Enzootic stability (herd immunity) in bovine babesiosis occurs when the rate of transmission (inoculation rate) of Babesia spp by the tick vector is sufficient to immunize a majority of susceptible calves before the loss of calfhood resistance. The effect of three tick (Boophilus microplus) control strategies (none, threshold, and strategic) on enzootic stability and the likelihood of babesiosis (Babesia bovis) outbreaks was studied using a spreadsheet age-class computer simulation model. The model was driven by weekly bovine tick counts from Brazil and Uruguay. The Eldorado do Sul, RS, Brazil bovine population (30 degrees 05' South latitude) was found to be in a naturally occurring state of enzootic stability, corresponding to an inoculation rate exceeding 0.005 throughout the year. Threshold dipping strategies should not increase the risk of babesiosis in cattle so managed. Strategic dipping resulted in an extended period of enzootic instability lasting 30 weeks, which requires protection of the herd through immunization. Because of the more prolonged low winter temperature conditions, the Tacuarembó, Uruguay bovine population (31 degrees 40' South latitude) was found to be in a naturally occurring state of enzootic instability, characterized by a 28 week period in which the inoculation rate was below 0.005. Strategic dipping should lead to eradication of the babesial parasite from tick and bovine populations, but would not result in eradication of the tick vector. This could lead to subsequent outbreaks if Babesia carrier animals were to be introduced into the herd. In both populations, strategic tick control could be accompanied by concurrent babesiosis vaccination.

Animals↗
PubMed1997

[Drug treatment for stable coronary artery disease at primary and tertiary medical centers].

PURPOSE: To observe the distribution of the main drugs used in patients with stable coronary heart disease, in primary and tertiary medical care centers (MCC). METHODS: We studied 300 consecutive out patients at the Hetat Institute with the diagnosis of stable coronary artery disease, 205 (68%) males and 95 (32%) female, aged from 31 to 80 (mean 58 +/- 8.0) years old. Drug intake was evaluated. RESULTS: We observed that the use of nitrates (48% vs 55%; p = NS) and calcium antagonists (46% vs 37%; p = NS), respectively in both primary and tertiary MCC was similar. The beta blockers were used more often in the primary MCC (50% vs 35%; p = 0.02). Angiotensin converting enzyme inhibitors (11% vs 42%; p < 0.001), diuretics (30% vs 49%; p = 0.002) and aspirin (44% vs 76%; p = 0.0001) were more frequently used in the tertiary MCC. CONCLUSION: We observed similar frequency of use of nitrates and calcium antagonists in both centers. There was a higher use of beta blockers in primary MCC. The angiotensin converting enzyme inhibitors and antiplatelet agents were more used in the tertiary MCC. In relation to the updated literature, the best pharmacotherapy to coronary artery disease should be optimized in both centers.

Adrenergic beta-Agonists↗
PubMed1997

Acute renal failure due to rhabdomyolysis in diabetic patients.

We report a 32-year-old Black man, admitted to the ICU with coma and severe metabolic disturbances due to diabetic ketoacidosis. During the admission, rhabdomyolysis and acute renal failure (ARF) were diagnosed. After metabolic control and gradual decrease of creatine kinase levels, he presented a progressive improvement of renal function. We emphasize nontraumatic rhabdomyolysis as a poorly recognized pathogenetic factor for ARF in diabetic ketoacidosis and suggest that a better understanding of its mechanisms and an early application of protective measures is necessary.

Acute Kidney Injury↗
PubMed1993

Anomalous structure of urinary chondroitin sulfate from cancer patients. A potential new marker for diagnosis of neoplasias.

BACKGROUND: Chondroitin sulfate is significantly increased in tumors (10 to 100 times) when compared to the amounts present in normal adjacent tissues. To investigate if the changes in concentration of chondroitin sulfate could be reflected in the urine of cancer patients we have analyzed the chondroitin sulfate excreted by 44 patients with different types of tumors, 50 normal individuals and 15 patients with unrelated diseases. EXPERIMENTAL DESIGN: The identification and structural analyses of the sulfated glycosaminoglycans were made by electrophoresis and degradation with specific enzymes (chondroitinases AC and ABC), identification/quantitation of their disaccharide products by chromatography (paper and HPLC) and chemical determinations. RESULTS: The disaccharide products formed from chondroitin sulfate of the 44 cancer patients by action of chondroitinase ABC show a substantial relative increase of non sulfated disaccharide (32.1% +/- 15.2) with a relative decrease of 6-sulfated disaccharide (28.9% +/- 11.5) and 4-sulfated disaccharide (39.0% +/- 13.5) when compared to the chondroitin sulfate of normal subjects (9.1% +/- 2.2, 40.6% +/- 4.5 and 50.2% +/- 4.5, respectively) or from patients with unrelated diseases. There is a direct correlation between the non sulfated disaccharide content and the stage of malignancy of the cancer patients. A significant change of the ratio of chondroitin sulfate and heparan sulfate and a decrease in the electrophoretic migration of chondroitin sulfate were also observed in cancer patients. CONCLUSIONS: All the cancer patients analyzed so far have shown the structural anomaly of the urinary chondroitin sulfate and this may be useful in the diagnosis and follow up of cancer therapy.

Adolescent↗
PubMed1991

[Effect of ticlopidine and dipyridamole on platelet aggregation and count in patients with chronic stable angina pectoris].

PURPOSE: To compare the ticlopidine and dipyridamole effects on platelets count and aggregation in patients with stable coronary artery disease. PATIENTS AND METHODS: Eighty patients with stable coronary artery disease and mean of 58.3 +/- 5.8 years were studied. They were divided into two equal groups of 40 patients and each one treated with ticlopidine or dipyridamole. Platelets count and aggregation were examined before treatment and at first and fourth weeks of treatment. RESULTS: At the end of fourth week of treatment, spontaneous, induced by ADP or by adrenalin platelet aggregation inhibition was observed, respectively, in 82.5%, 72.5% e 67.5% of the patients in ticlopidine group. The spontaneous, induced by ADP or by adrenalin, platelet aggregation inhibition in the patients of dipyridamole group was, respectively, 40%, 30% e 27.5% (p less than 0.001). The platelets count did not change in both groups. CONCLUSION: The ticlopidine effect is much more evident in platelet aggregation inhibition than dipyridamole, and maybe a choice in the prevention of cardiovascular events.

Coronary Disease↗