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Biomedical subjects

R Gamboa

Publications and source records attributed to R Gamboa.

At least 19 recordsLinked to original sources
PubMed2002

LMP2 and LMP7 gene polymorphism in Mexican populations: Mestizos and Amerindians.

Low molecular weight polypeptide (LMP) genes are located within the major histocompatibility complex and have been associated with autoimmune diseases such as ankylosing spondylitis. In order to define the distribution of LMP genes in Mexican populations, the LMP2 and LMP7 polymorphism was analyzed in 312 Mexican individuals (95 Mexican Mestizos, 48 Nahuas, 56 Mazatecans, 50 Teenek, and 63 Mayos) belonging to different ethnic groups. In Mexican populations both Mestizos and Amerindians presented similar distribution of LMP2 and LMP7 polymorphisms, except Nahuas and Mayos who presented the higher frequencies of LMP2-H/H and the lowest frequencies of LMP2-H/R genotypes (P < 0.05 when compared with Mexican Mestizos). The LMP7-K/K genotype was absent in Nahuas, Teenek and Mayos and only one Mazatecan individual presented this genotype. Differences with other populations were found in Mexicans. An increased frequency of LMP2-H and a decreased frequency of LMP2-R alleles were observed in Mexican Amerindians (Nahuas and Mayos) when compared with Brazilian Amerindians (Kaingang and Guarani) and Caucasians (Spaniards) (P < 0.05). All Mexican populations (Mestizos and Amerindians) presented an increased frequency of LMP7-Q allele and a decreased frequency of LMP7-K allele when compared to Brazilian Amerindians (Kaingang), Caucasians (United States) and Asian (Japan) populations (P < 0.05). Genetic distances showed that Mexican Mestizos have an important relation with Spaniards and with all Mexican Amerindians. The present data corroborate the influence of Spaniard and Amerindian genes in the Mexican Mestizo population and could help to define the true significance of LMP polymorphism as genetic and evolutive marker in the Amerindian populations.

Biological Evolution↗
PubMed2002

Heat shock protein 70 gene polymorphisms in Mexican patients with spondyloarthropathies.

OBJECTIVE: To investigate the role of HSP70 genes as contributors to genetic susceptibility of the spondyloarthropathies (SpA) in the Mexican population. METHODS: The study included 150 patients with SpA (undifferentiated spondyloarthropathy (uSpA) 68, ankylosing spondylitis (AS) 60, and reactive arthritis 22) and 158 healthy controls. HSP70-1, HSP70-2 and HSP70-hom genotypes were analysed by the polymerase chain reaction-restriction fragment length polymorphism technique. Statistical methods included the Mantel-Haenzel, chi(2), Fisher's exact test, and Woolf's method for odds ratio (OR). RESULTS: HSP70-2 B/B genotype frequency was increased in the whole group of patients with SpA (pC<0.05, OR=4.3), as well as in the different clinical subgroups (pC<0.05, OR=4.2 for AS; pC<0.05, OR=4.4 for uSpA; and pC<0.05, OR=4.1 for ReA). This frequency remained significantly increased when the patients with B27 negative SpA were analysed. On the other hand, HSP70-hom locus analysis showed significantly increased frequency of A allele in the whole group of SpA (pC<0.05, OR=3.4), as well as in the groups with AS (pC<0.05, OR=5.6) and with uSpA (pC<0.05, OR=3.1), when compared with healthy controls. In this case, also, the genotype A/A was increased in the whole group of SpA (pC<0.05, OR=4.5), as well as in patients with AS (pC<0.05, OR=6.4) and with uSpA (pC<0.05, OR=3.7). When the patients with B27 negative SpA were analysed the frequencies of HSP70-hom A allele and A/A genotype remained significantly increased in the whole group of SpA (pC<0.05, OR=3.2 for the A allele and pC<0.05, OR=4.2 for the A/A genotype) and in the uSpA subgroup (pC<0.05, OR=3.8 for the A allele and pC<0.05, OR=4.3 for the A/A genotype). CONCLUSION: In addition to the association of SpA with HLA-B27, there is a significant association of HSP70-2 and HSP70-hom alleles with SpA in Mexicans. This association seems to be independent of the susceptibility conferred by HLA-B27 in the group of patients with uSpA.

Adult↗
PubMed2001

Polymorphism and distribution of HLA-DR2 alleles in Mexican populations.

DRB1*15/16 nucleotide polymorphism was analyzed in 68 DR2 positive individuals (18 Mexican Mestizos, 30 Mazatecans and 20 Nahuas), carrying a total of 75 DR2 haplotypes. HLA-DR2 was one of the most frequent specificities detected in Mazatecans and Nahuas with gene frequency (gf) of 0.232 and 0.141, respectively. In these populations DRB1*16 was the most frequent DR2 split (gf = 0.183 in Mazatecans and gf = 0.135 in Nahuas), whereas in Mexican Mestizos the most frequent was DRB1*15 (gf = 0.065). Four DRB1-DQB1 combinations in Mexican Mestizos, two in Mazatecans and one in Nahuas were in linkage disequilibrium. In spite of the restricted polymorphism, there were differences on DRB1*15/16 alleles found in Mexicans. DRB1*1501 a Caucasian allele was predominant in Mexican Mestizos, whereas DRB1*1602 an Amerindian allele was characteristic on Indian populations. An important difference was detected among the Amerindian populations studied since DRB1*1502 was only present in Mazatecans. This data corroborates the restricted polymorphism of DRB1*15/16 and the high frequency of DRB1*16 subtype in autochthonous American populations and suggest that the differences in gene frequencies of DRB1*15/16 alleles could be helpful in distinguishing each of these population.

Alleles↗
PubMed2001

Influence of the apolipoprotein E polymorphism on plasma lipoproteins in a Mexican population.

The influence of apolipoprotein E (APOE) genotypes on plasma lipid levels was determined in 278 Mexican individuals. The most frequent genotype was E3/3 (80.5%) followed by E3/4 (12.5%), E2/3 (5.0%), E2/4 (1.4%), and E4/4 (0.3%). Our data are similar to those previously described for Mexican-American and American Indian populations, which show the highest frequency worldwide of the APOE*3 and the E3/3 genotype. Compared to female carriers of the E3/3 genotype, women with the E3/4 genotype presented increased low-density lipoprotein cholesterol (117 +/- 28.0 mg/dL vs. 134.0 +/- 31.7 mg/dL, p < 0.05), and total cholesterol (179.4 +/- 33.4 mg/dL vs. 197.5 +/- 35.4 mg/dL, p < 0.01). Also, we detected increased high-density lipoprotein concentrations in women with the E2/3 genotype (53.7 +/- 19.5 mg/dL) when compared to women with the E3/3 genotype (45.2 +/- 12.0 mg/dL) (p < 0.032). Our data suggest that genetic variation at the APOE locus in the Mexican population is a genetic factor that influences plasma lipid levels. This effect was observed only in the female population. Additional studies attempting to correlate APOE polymorphism with plasma lipid profile in a large number of individuals would be helpful in establishing the true significance of this polymorphism in the Mexican population.

Adult↗
PubMed2000

DNA sequencing of HLA-B alleles in Mexican patients with Takayasu arteritis.

Takayasu arteritis (TA) is characterized by a 'pulseless' condition and occurs frequently in young females from Asian and South American countries. It has been associated with Mayor Histocompatibility Complex (MHC) genes in different populations. Recent data indicate direct participation of HLA-B alleles in the susceptibility to the disease. This fact was explored in an associative study with TA to establish if some region in the exon 2, intron 2 or in the exon 3 of HLA-B alleles is common in the alleles associated with TA and at the same time to know if a specific sequence or an epitope, more than an allele, would be responsible for the susceptibility to this vasculitis. We studied HLA-B alleles of 12 Mexican patients with TA using PCR-SSP and sequencing. The analysis by PCR-SSP in 12 patients showed that five of them showed the B*15 allele, three the B*40 allele and two the B*39 allele, the remaining two presented the B*44 allele. Sequence analysis enabled us to define that the B*39 subtypes are B*3908; B*15 subtypes are B*1510, B*1515, B*1522 and B*1531; and the B*40 subtypes are B*4005 and B*4008. An individual with B*51 (B*5107) and another with B*52 (B*5201) alleles were also identified. The sequences of the intron 2 seem be heterogeneous. Analysis at the 63 and 67 positions of HLA-B alleles showed that 9 of them have similarity in some of these positions with the residues detected in the B*5201 and B*3902 alleles associated with TA in Asian populations. The results indicate that there is heterogeneity in the alleles associated with TA in Mexicans but, in spite of that heterogeneity, the alleles associates can be separated into three groups: B*39, B*15 and B*40, whose subtypes are rare and apparently of recent generation in Mexico, probably by recombination events at intron 2 level. The sequences analysis also shows that most of the alleles detected in the Mexican patients share two epitopes described in the susceptibility alleles in Asian populations, suggesting that these epitopes could be responsible for the susceptibility to develop the disease in spite of the allele in which are found.

Alleles↗
PubMed2000

HLA-DR4 allele frequencies on Indian and Mestizo population from Mexico.

Using PCR-SSOP and sequencing, we examined DRB1*04 nucleotide polymorphism in 137 DR4-positive Mexican healthy individuals (46 Mexican Mestizos, 64 Mazatecans, and 27 Nahuas), carrying a total of 147 DR4 haplotypes. Eleven different DRB1*04 alleles were detected in Mexican Mestizo population, whereas, in the two Indian groups a restricted polymorphism was observed (5 variants in Mazatecans and 4 in Nahuas). DRB1*0407 was the most frequent allele (gf = 0.106 in Mexican Mestizos, gf = 0.281 in Mazatecans, and gf = 0.189 in Nahuas). In spite of the restriction in polymorphism, there were differences on DRB1*04 alleles found in Mexicans mainly between Mazatecan and Nahua populations. DRB1*0403 was characteristic allele in Nahua ethnic group, whereas, 0404 and 0411 were predominant alleles in Mazatecans. This data corroborates the restricted polymorphism of DRB1*04 alleles in American populations. In spite of the restriction in this polymorphism, differences in frequencies of DRB1*04 alleles could help distinguish each population.

Gene Frequency↗
PubMed2000

Lack of association between the polymorphism at the heat-shock protein (HSP70-2) gene and systemic lupus erythematosus (SLE) in the Mexican mestizo population.

Major histocompatibility complex (MHC) alleles have been recognized as genetic factors for developing systemic lupus erythematosus (SLE). In the present study we analyzed whether a heat-shock protein gene (HSP70-2) is involved in determining susceptibility to develop SLE in a Mexican Mestizo population. A HSP70-2 Pst I polymorphism was detected by a restriction fragment length polymorphism analysis of polymerase chain reaction (PCR-RFLP) in 107 SLE patients and 158 healthy controls. No statistically significant differences were observed in the HSP70-2 allele distribution between patients and healthy controls. HLA-DR analysis showed an increased frequency of HLA-DR3 allele in the patients group (P < 0.05, OR = 2.26, EF = 6.0%). On the other hand, when we analyzed HSP70-2 polymorphism in relation to HLA-DR3 allele, we could only detect an increased frequency of AB genotype in the DR3 negative patients (pC < 0.05, RR = 2.6, EF = 11.3%). Linkage disequilibrium was observed for three haplotypes: HLA-DR3-HSP70-2A (D = 0.03, D' = 0.67, P < 0.01); HLA-DR1-HSP70-2A (D = 0.03, D' = 0.86, P < 0.01) and HLA-DR8-HSP70-2B (D = 0.02, D' = 0.46, P = 0.02). Our data indicate that HSP70-2 gene polymorphism as opposed to the other ethnic groups does not appear to be relevant in SLE susceptibility in Mexican patients and that the distribution of the different alleles depend on the frequency of HLA alleles associated with them.

Alleles↗
PubMed2000

Apolipoprotein E polymorphism in the Indian and Mestizo populations of Mexico.

Apolipoprotein E (APOE) genotypes were determined in 75 Mazatecan Indians and 83 Mexican mestizos. APOE allele and genotype frequencies in Mazatecans and mestizos were similar, with high frequencies of the APOE*3 allele (0.900 and 0.915, respectively) and the E3/3 genotype (0.813 and 0.831, respectively) and an absence in both samples of the APOE*2 allele. Our data are similar to those previously described for Mexican-American and Mayan populations, which show the highest frequency worldwide of the APOE*3 allele and the E3/3 genotype. Mazatecans and mestizos also show a decreased frequency of the APOE*4 allele when compared to other Amerindian groups. The absence of the APOE*2 allele has also been reported in other Amerindian groups such as Mayans and Cayapa, whereas in Caucasians the average frequency of this allele is about 8%. Our data are in agreement with previous reports showing absence of the APOE*2 allele in Native American groups. These findings suggest that the APOE*2 allele was absent in humans from northern Asia who settled in the Arctic and populated the American continent.

Adult↗
PubMed1999

HLA-DRB and HLA-DQB loci in the genetic susceptibility to develop glaucoma in Mexicans.

PURPOSE: Glaucoma is a clinically heterogeneous disease with a pathophysiology that may include genetic susceptibility, possibly associated with an immunologic disorder. The aim of this study was to determine whether the DNA polymorphisms located in the HLA-DRB1 and HLA-DQB1 genes show a specific association pattern in Mexican mestizo patients with primary open-angle glaucoma. METHODS: This was a cross-sectional, case-control, multicenter study. We analyzed the HLA-DRB1 and DQB1 loci of 81 Mexican mestizo nonrelated patients with primary open-angle glaucoma and 98 healthy ethnic matched control subjects. Patients were diagnosed clinically and by visual fields examination. HLA typing was performed by PCR-SSO reverse dot blot. RESULTS: We documented increased frequencies of HLA-DRB1*0301, DRB1*1101, DRB1*0701, DRB1*1402, DQB1*0302, and DQB1*0301; however, none of them were significantly different from normal control subjects. Haplotype analysis showed that the HLA-DRB1*0407-DQB1*0302 haplotype is significantly increased in patients compared with control subjects (P = .0001). CONCLUSIONS: The haplotype HLA-DRB1*0407-DQB1*0302 is common among Mexican mestizo (haplotype frequency = 0.102), and it was increased in our patients (haplotype frequency = 0.259, P = .0001). This may reflect an independent association of this haplotype with the disease as the result of linkage disequilibrium or the influence of a neighboring gene. The pathophysiology of this illness is uncertain, and further studies are needed regarding the genetic susceptibility to develop primary open-angle glaucoma.

Alleles↗
PubMed1999

Heat-shock protein (HSP70-2) allelic frequencies in three distinct Mexican populations.

The major histocompatibility complex (MHC) genes are highly polymorphic and therefore have been useful in population genetics and disease association studies. We analyzed restriction fragment length polymorphism of HSP70-2 alleles in healthy unrelated Mestizo, Mazatecan and Nahua populations. Both Indian groups, Mazatecans and Nahuas, were in Hardy-Weinberg equilibrium, while Mestizos were in disequilibrium (chi 2 = 0.399; P < 0.05). The Mazatecan Indians presented a high frequency of BB homozygosity (17.35%) compared to Mestizos (5%) (P = 0.01). Mexican ethnic groups present differences in distribution of BB genotype. The low frequency of BB genotype in Mestizos may be the result of a negative selection process.

Alleles↗
PubMed1997

[Salmonella enteritidis, an emergent pathogen in Chile].

BACKGROUND: Salmonella enteritidis infections have increased worldwide in the last years. Isolation of this pathogen was remarkably rare in Chile until 1994, when the still ongoing outbreak emerged. AIM: To assess the main epidemiological characteristics of the Salmonella enteritidis epidemic in Chile. MATERIALS AND METHODS: Cases of clinical infections by Salmonella enteritidis were recorded from bacteriological and demographic notifications obtained at The National Reference Laboratory for Enterobacteria. Infection rates were calculated using the total Chilean population and the population of the different Health Services along the country. RESULTS: Until 1993, 13.67 Salmonella enteritidis strains per year were received at the Reference Laboratory. The figures increased to 478 and 432 in 1994 and 1995, respectively. National rates were 3.41 and 3.04 notifications/100,000 inhabitants in 1994 and 1995 respectively. Northern regions were the most affected and 90% of observed cases during 1994 came from Arica and Antofagasta. At the present time, 20% of cases are observed in Santiago, located in the mid-portion of the country. The outbreak has mainly affected children and young adults (70% of cases). Strains have been isolated from stool cultures, suggesting gastrointestinal infections as the main clinical presentation. More than 98% of strains are susceptible to chloramphenicol, ampicillin, tetracycline, sulfa-trimetroprim, cefotaxime or ciprofloxacin. CONCLUSIONS: The obtained data clearly indicate the existence of an epidemic outbreak of Salmonella enteritidis infections, with a geographic progression from North to South.

Chile↗
PubMed1996

[Perforation of surgical gloves during cesarean section].

We carried out a prospective study with the object of knowing the frequency of surgical gloves perforation during cesarean section, the member of the surgical team with a major affection and the double gloves importance. We analysed 258 C. section practiced in the Tocosurgery's Service at "Nuevo Hospital Civil de Guadalajara" from September 1993 to January 1994. We used 1052 glove's pairs and we detected 118 perforated pairs (11.2%). The gloves were perforated in one time 60.1%, in two times 26.2%, in three times 6.8%, in four times 1.7% and five times 5.2%. On the other hand, in the he perforated gloves, 74% were simple gloves, while in 26% were double gloves, but only the external glove was perforated. The member of the surgical team with major affectation was the Surgeon with 83%, next the assistant in 13.5% and for last the instrumentist in 3.5%. The left hand was more affected that the right hand. The glove perforations more frequently was done for needle and after for instruments. We concluded that the use of double gloves is correct for a major protection, besides that the C. section must be carefully practiced.

Cesarean Section↗
PubMed1995

[Polyhydramnios and its relationship with congenital malformations: ultrasonographic diagnosis].

We analyzed the occurrence of polyhydramnios during pregnancy and to indicate the association with congenital abnormalities of the product and maternal alterations. A retrospective descriptive and transversal study was performed which included 6087 pregnant patients who were submitted to ultrasonographic studies from January 1, 1991 to December 31, 1993. The final sample consisted of 72 patients with criteria of polyhydramnios and who had a complete, clinical history, specific data concerning the reproductive history and maternal risk factors associated with polyhydramnios and fetal malformations was compiled. The occurrence of polyhydramnios during pregnancy was 1.1% and the association with congenital malformations was 13.8%, being the majority neural tube defects. The maternal alterations were related in 13.7% to polyhydramnios, being primary cause gestational diabetes. Anencephalia presented a significant statistics (p < 0.05). The occurrence of polyhydramnios is low in obstetric patients. Neural tube defects such as anencephalia are the primary fetal defects. Gestational diabetes and multiple gestations are the more significant maternal alterations.

Adolescent↗
PubMed1994

[Seroprevalence of hepatitis C virus antibodies in obstetric patients at the Nuevo Hospital Civil de Guadalajara].

The hepatitis C virus is the predominant cause of parental transmission of hepatitis. The importance to recognize the prevalence of this virus in obstetrics patients is the possible vertical transmission of mother to child which has been reported by various authors. The objective of this investigation was to determine the presence of antibodies of the hepatitis C virus in the obstetrical population of the Nuevo Hospital Civil de Guadalajara. Selection was made at random; questionnaires were applied to identify factors of associated risks. Of the 244 patients studied, the prevalence was found in 2% (n = 5). The only risk factor closely related was previous blood transfusion (P < 0.00004964) with a relative risk of 29.6 for the obstetrics population with previous transfusion.

Adolescent↗
PubMed1993

[Guillain-Barré syndrome and pregnancy].

Guillain-Barré syndrome is a rare occurrence in pregnant women. We describe the case of a 21-year old woman, seen at "Nuevo Hospital Civil de Guadalajara" with a term pregnancy, who presented with limbs weakness and paresthesias, drowsiness and malaise. Her vital signs were normal but she was quadriparetic, there was muscular atrophy in the extremities and deep tendon reflexes were decreased. Spinal fluid analysis revealed a protein of 71.2 mg/dl, glucosa 48 mg/dl and no white cells and both Gram stain and routine cultures were negative. EMG studies reported poliradiculoneuritis; a C-section was done, and both the mother and a newborn girl did very well. Guillain-Barré syndrome should be suspected in similar cases in order to offer prompt intervention.

Adult↗
PubMed1993

[Percutaneous balloon valvotomy in neonatal obstructive cardiopathy. I: critical pulmonary valvular stenosis].

Percutaneous pulmonary balloon valvotomy using one balloon or more in sequential approach was attempted in 9 no selected neonates with critical pulmonary valve stenosis between March 1985 and October 1990 (mean age 10 + 8.6 days). The procedure was successful in seven of them (78%) in whom with a 1.22 + 0.2 balloon/annulus ratio the right ventricular systolic pressure decreased from 96 to 45 mmHg (p < 0.001), the transvalvular gradient from 65 to 23 mmHg (p < 0.001); and the systemic oxygen saturation increased from 69 to 86% (p < 0.001). In one patient the valve was not crossed. Two patients underwent surgery because unsuccessful balloon valvotomy result in the immediate and mid term period: hypoplastic right ventricle in one, and inferior vena cava thrombosis that prevent a second dilation in the other respectively. The mid term follow up showed a 62% (5/8) of successful result. Although the complex methodology and complications are not uncommon, the balloon pulmonary valvotomy is a safely and effective therapy for neonates with critical pulmonary stenosis.

Angiography↗
PubMed1993

[Percutaneous balloon valvotomy in neonatal obstructive cardiopathy. II. Critical aortic valve stenosis].

Percutaneous balloon aortic valvotomy using one or more balloons in sequential approach was attempted in 11 non selected neonates with critical aortic valve stenosis. The procedure was complete in 9 (81%), and they represent the study group with a mean age of 19 days. Using a balloon/annulus ratio of 0.86, the transvalvar gradient decreased from 49 to 25 mmHg, and left ventricular systolic pressure fell from 112 mmHg to 96 mmHg (p < 0.01, respectively). Fifty-five percent (5/9) of the patients developed a new aortic regurgitation, only one with grade 3. The maximal instantaneous Doppler gradient recorded in 7 neonates before and after valvotomy dropped from 67 to 35 mmHg (p < 0.01); while the left ventricular shortening fraction increased from 15 to 31% (p < 0.01). The Doppler gradient was correlated with the left ventricular shortening fraction (r:0.72) and the aortic regurgitation with the balloon/annulus ratio (r:0.82). The balloon pulmonary valvotomy was unsuccessful in 2 neonates (22%), both with hypoplastic left ventricle, both of which died in the operating room. Echocardiographic features of reestenosis were not found in the follow-up period (14 +/- 10 months); only one patient may need a future surgical intervention because significant aortic insufficiency. The pulmonary balloon valvotomy is a safe and effective therapy that must be used as the first step in the management of neonates with critical aortic stenosis in absence of hypoplastic left ventricle.

Aortic Valve Stenosis↗