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Biomedical subjects

R Bolaños

Publications and source records attributed to R Bolaños.

At least 19 recordsLinked to original sources
PubMed1999

Class II major histocompatibility complex typing across the ethnic barrier in pemphigoid gestationis. A study in Mexicans.

BACKGROUND: Pemphigoid gestationis (PG), also called herpes gestationis, is a rare autoimmune disease of pregnancy or puerperium (estimated 1 out of 50,000 pregnancies among Caucasians). A previous series has demonstrated an association of PG with human leukocyte antigen (HLA)-DR3 or HLA-DR4 haplotypes. While these haplotypes are most commonly found in individuals of European ancestry, they have also been found in African-American patients affected with PG. PG has rarely been reported in other ethnic groups, and the HLA association in non-Europeans has not been examined. METHODS: We have characterized eight patients of Mexican ancestry who have PG by clinical, histologic, and immunofluorescence criteria. Class I and class II major histocompatibility complex (MHC) antigens were studied by standard microlymphocytotoxicity assays. Class II MHC antigens were further studied by polymerase chain reaction (PCR) amplification of HLA-DRB1, DQA, and DQB genes and allele-specific oligonucleotide hybridization. For comparison purposes, we used results obtained from a group of 100 ethnically matched healthy individuals. RESULTS: We found that all eight patients had the HLA-DR3/DR4 phenotype; all HLA-DR3 haplotypes were HLA-DRB1*0301, DQA1*0501, and DQB1*0201, whereas half of the HLA-DR4 haplotypes were from the DRB1*0401 subtype and the other half were DRB1 *0407. CONCLUSIONS: These results suggest that, in Mexicans, the genetic susceptibility for the development of PG is strongly influenced by the genetic admixture of Caucasian origin, and the role of class II MHC antigens in the pathophysiology of this disease is confirmed.

Adolescent↗
PubMed1997

[Analysis of the 50g glucose test at the National Institute of Perinatology].

Gestational diabetes (GD), is a common illness in our country, that is associated with high perinatal morbi-mortality. The objective of this study is to assess the utility of the 50 g glucose screen test (GST) to know the frequency of GD at the National Institute of Perinatology, for preventing the neonatal risks associated with this pathology. For that reason, we performed a one year prospective study including 144 pregnant patients between 24-28 weeks of gestation. All of the patients undergo the 50g GST, and those with results or = to 140 mg/dl were followed by the glucose tolerance test (GTT). This GTT was performed with 100g of glucose and then blood samples were taken at fasting time, later at 60-120-180 minutes respectively. Of the total of 144 patients, 33 (23%), resulted with a positive GST. The GTT confirms the GD in 10.7% of the patients, and an equal proportion of gestational alterations to the GTT was observed. It is concluded that the 50 g GST is the best screening test to identify alterations of the carbohydrate metabolism during pregnancy.

Adolescent↗
PubMed1994

[Therapeutic efficacy of ursodeoxycholic acid in persistent gallbladder lithiasis and persistent biliary sludge: preliminary results of a multicenter experience].

A prospective and multicenter study was performed to determine the efficacy and tolerance of ursodeoxycholic acid (UDCA) in the treatment of gallstones and biliary sludge. Criteria for entry into the trial were radiolucent gallbladder stones; until 20 mm of size and visualization of the gallbladder by oral cholecystography. Too were treatment the patients with persistent biliary sludge (PBS) defined by the persistence of the biliary sludge in two consecutive echography along three months. Without severe gallbladder disease. Then daily UDCA doses of 600 mg were suminstred divided in two postprandial times for a six months period. The control to the treatment were: basal ultrasonography (US) of the gallbladder and by follow-up gallbladder US for six months; clinical examination every month and cholecystography before and after the treatment. Of 110 admitted patients, 19 (17%) stopped the treatment for no-medical reasons and 91 (83%) arrived to the and point. After six months of treatment, complete dissolution was observed in 50% of the patients (46/91), partial in the 43% (39/91) and failed the treatment in 6.5% (6/91) who presented high density stones for computed tomography, CT (greater than 60 UH). According to pattern of lithiasis dissolution was complete in 100% (22/22) of the patients with PBS; 71.4% (10/14) in microlithiasis and 25% (14/55) in macrolithiasis. Minor adverse effects were acidism in the 7.7% (7/91) and diarrhea in the 1.1% (1/91). In the other hand, one patient presented acute pancreatitis (1/91; 1.1%), it must be discussed if was a complication of the lithiasis or an therapeutic effect. The UDCA was a safe and effective treatment without lethality in PBS and in microlithiasis while in case of macrolithiasis must be standardized response criterion, for example density stones for CT.

Adult↗
PubMed1988

[Spermatogonia types in tepezcuintle (Cuniculus paca). Ultrastructural study].

Ultrastructural studies of different types of spermatogonia by thin section techniques and transmission electron microscopy showed that Cuniculus paca has two types of Type A spermatogonia (A-O and A-1). Samples were taken at different stages of the cycle in the seminiferous tubule epithelium presented a similar pattern as those of other rodents. Type B spermatogonia are similar to those of the rat, the difference being that the heterochromatic zones are larger and more numerous. Both characteristics differentiate them from preleptotenic spermatocytes.

Animals↗
PubMed1985

[Alterations in the coagulation mechanisms of patients bitten by Bothrops asper (Terciopelo)].

Blood from eighteen patients bitten by B. asper were studied for effects on coagulation. All showed alterations in the levels of fibrinogen and of factors II, V, VIII, IX, X and XI, as well as in anti-thrombin-III and plasminogen. The number of platelets and the concentrations of factors VII and XII did not show significant variations in comparison with the controls. The biological assay of fibrinogen, the quantitation of fibrinogen degradation products and of factor II and the general coagulation tests, such as prothrombin and partial thromboplastin times, showed a good correlation with the severity of the envenomation. In snakebites by B. asper there is a severe hypofibrinogenemia, with fibrin degradation by activation in the fibrinolytic system and with activation and consumption of factor II. Intramuscular emergency treatment with small quantities of antivenom did not prevent the above noted alterations in coagulation.

Blood Coagulation↗
PubMed1984

Scanning electron microscopy of the final phase of the life cycle of Trypanosoma cruzi in the insect vector.

Scanning electron micrographs showed that both epimastigotes and metacyclic trypomastigotes of Trypanosoma cruzi are attached by the flagellum to the epithelium of the rectal gland of Triatoma dimidiata. The flagellates tended to cover the surface of the gland and there was a marked predominance of epimastigotes with a round posterior end. Reproduction and metacyclogenesis seem to take place in situ, the latter apparently by twisting and elongation of the epimastigotes. Metatrypomastigotes remain attached for some time, probably by a weaker mechanism which easily allows them to loosen, facilitating expulsion with the urine or feces.

Animals↗
PubMed1982

[Biomedical aspects of 4 cases of snake bites by Lachesis muta (Ophidia: Viperidae) in Costa Rica].

Three out of four cases of snake bite by Lachesis muta stenophrys (Bushmaster) in Costa Rica were fatal and one recovered after a long period of hospitalization. Initial symptoms were similar to those of bothropic envenomation: intense pain, nausea, vomiting, sweating, and excitability, but differing in the magnitude of a tremendous edema and in the absence of intensive bleeding and phlyctenae. We found important alterations in arterial blood pressure and in the activity and concentration of coagulation factors. All patients showed infections, and necrosis was found in at least three of them.

Antivenins↗
PubMed1981

[Neutralization of local effects of Bothrops asper venom by polyvalent antivenin].

Neutralization of lethality, myonecrosis, hemorrhage and edema induced by Bothrops asper venom in mice was studied using the polyvalent antivenom produced in the Instituto Clodomiro Picado. The neutralizing effect (ED50) on each of these toxic activities varied; the neutralization of lethal and hemorrhagic effects being more effective than the neutralization of myonecrosis and edema. With independent inoculation of venom and antivenom, antivenom was not effective in neutralizing edema-forming activity. The myonecrotic effect was only partially neutralized when serum was given i.v. immediately after envenomation; however, antivenin effectively neutralized the hemorrhagic activity. The ineffectiveness of antivenom in neutralizing edema and myonecrosis could be partially explained by the rapid development of these effects. Hence, the time interval between envenomation and antivenom administration and the route of serum administration both play an important role in the neutralization of local effects.

Animals↗
PubMed1980

[Comparative study of venoms of newborn and adult specimens of Bothrops asper].

This paper is a comparative study of venoms of newborn and adult specimens of Bothrops asper from two Costa Rican populations: San Carlos, in the Atlantic versant and Puriscal in the Pacific. Comparison was on a basis of determination of the following effects: hemorrhage, myonecrosis, edema, proteolysis, hemolysis, and lethality, as well as neutralization of the lethal effect by polyvalent antivenom. Biochemical and immunochemical comparisons were done by means of electrophoresis, immunoelectrophoresis, and immunodiffusion. There are marked differences between newborn and adult venoms from both regions in electrophoretic and immunoelectrophoretic patterns, although the immunodiffusion plates showed an almost identical pattern. Venoms from newborn specimens are more proteolytic, hemorrhagic, edema-forming and lethal, whereas those of adult specimens are more hemolytic and induce a stronger myonecrotic action, characterized by a myolitic type of necrosis. Antivenom neutralizes the lethality of all venoms with similar ED50. Venoms of adult specimens from both regions showed a slight variation in the immunoelectrophoretic pattern, but a complete identity in immunodiffusion plates. Adult venoms from San Carlos are more hemorrhagic, and myonecrotic, whereas those of Puriscal are more proteolytic, having similar lethality, edema-forming activity, and hemolytic effect. The same differences were observed when venoms from newborn specimens from both populations were compared.

Age Factors↗
PubMed1978

Plasmodium pessoai sp. n. from two Costa Rican snakes.

A unique malaria parasite species was found in 1/1 Spilotes pullatus (Colubridae) and 1/70 Lachesis muta (Crotalidae) from the moist Atlantic lowland forests of eastern Costa Rica. It is distinguished by small, sausage-shaped gametocytes (x 10.4 by 4.6 mu), growing schizonts that often contain a noticeable digestive vacuole with the contents partially visible, and striking spherical or bouquet-shaped segmenters whose precise merozoite numbers are difficult to discern (about 22-32) because of an intensely staining magenta or rose-colored substance in the matrix of the surrounding vacuole.

Animals↗