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Biomedical subjects

A R Torres

Publications and source records attributed to A R Torres.

At least 19 recordsLinked to original sources
PubMed2001

The association of MHC genes with autism.

Several immune abnormalities have been noted in autistic subjects. These associations have been extended to the Major Histocompatibility Complex (MHC), a section of DNA remarkable for the number of encoded proteins with immunological functions. The strongest MHC association identified thus far is for the null allele of C4B in the class III region. The complex allelic composition of C4 as determined by immunoelectrophoresis is discussed. Low levels of C4 resulting from the null allele may be important in disease pathogenesis especially since C4 has been identified in developing brain neurons. The DNA region just telomeric to C4 has several genes including tumor necrosis factor which encode proteins with immunological functions. These proteins may act in concert with C4 in disease contribution and the genes should be more closely examined.

Autistic Disorder↗
PubMed2000

Evaluation of an immunocapture-agglutination test (Brucellacapt) for serodiagnosis of human brucellosis.

We evaluated the validity and the usefulness of a new test for the diagnosis of human brucellosis based on an immunocapture-agglutination technique. A total of 315 sera from 82 patients with a diagnosis of brucellosis, 157 sera from patients in whom brucellosis was suspected but not confirmed, and 412 sera from people living in rural areas with endemic brucellosis were studied. The seroagglutination test (SAT), Coombs anti-Brucella test, and Brucellacapt test were evaluated. All the initial sera from the 82 patients proved to be positive in Brucellacapt and Coombs tests, while only 75 (91.4%) were positive in the SAT. If a >/=1/160 diagnostic threshold titer was defined for the Brucellacapt test, Coombs test, and SAT, the sensitivities were 95.1, 91.5, and 65.8%, respectively. Taking the same diagnostic threshold titer for the 157 sera from the unconfirmed but suspected patients, the specificities of the Brucellacapt, Coombs, and SAT were 81.5, 96.2, and 100%, respectively; for the 412 control sera, the specificities were 99.0, 99.8, and 100%. The diagnostic efficiency (area below the receiver operating characteristic curve) of Brucellacapt was 0.987852 (95% confidence interval [CI], 0.95109 to 0.99286), very similar to the diagnostic efficiency of the Coombs test (0.97611; 95% CI, 0.94781 to 0.99146) and higher than that of SAT (0.91013; 95% CI, 0.86649 to 0.94317). The results of the Brucellacapt test were compared with those of the Coombs test (correlation coefficient, 0.956; P = 0.000) and SAT (correlation coefficient, 0.866; P = 0.000). The study shows very good correlation between the Brucellacapt and Coombs tests, with a high concordance between titers obtained in the two tests. Nevertheless, lower correlation and concordance were found between the Brucellacapt and Coombs tests when the results for titers of >/=1/160 were compared (0.692; P = 0.000). In acute brucellosis, the Brucellacapt and Coombs tests render positive titers of >/=1/160. When the titers are lower, they increase significantly in the following 30 days, despite the evolution of SAT titers. In contrast, Brucellacapt and Coombs titers are always high (>/=1/640) in brucellosis with long evolution, whether SAT titers are higher or lower than 1/160.

Adolescent↗
PubMed1999

Human immunodeficiency virus antibody testing by enzyme-linked fluorescent and western blot assays using serum, gingival-crevicular transudate, and urine samples.

The aim of the present study was to evaluate the possible utilization of saliva and urine as alternative samples to serum for the diagnosis of human immunodeficiency virus (HIV) infection. A total of 302 individuals participated in the study: 187 HIV-infected individuals (106 had Centers for Disease Control and Prevention [CDC] stage II infection, 19 had CDC stage III infection, and 62 had CDC stage IV infection) and 115 noninfected persons (46 of the noninfected persons were blood donors and 69 belonged to a group at high risk of HIV infection). Paired saliva and urine samples were taken from each of the participants in the study. The presence of HIV-specific antibodies was detected by an enzyme-linked fluorescent assay (ELFA), and the result was confirmed by Western blot analysis (WB). The ELFA with saliva gave maximum sensitivity and specificity values, while ELFA had lower sensitivity (95.2%) and specificity (97. 4%) values for detection of HIV antibody in urine samples. WB with all saliva samples fulfilled the World Health Organization criterion for positivity, while only 96.8% of the urine samples were confirmed to be positive by WB. Among the four reactivity patterns found by WB of these alternative samples, the most frequent included bands against three groups of HIV structural proteins (was ENV, POL, and GAG). The reactivity bands most frequently observed were those for the proteins gp160 and gp120. The least common reactivity band was the band for protein p17. The detection of HIV antibodies in saliva samples by means of ELFA with the possibility of later confirmation by WB makes saliva an alternative to serum for possible use in the diagnosis of infection. In contrast, HIV antibody detection in urine samples by the same methodology (ELFA) could be taken into consideration for use in epidemiological studies.

AIDS Serodiagnosis↗
PubMed1997

Echinacea-induced cytokine production by human macrophages.

Echinacea purpurea, a plant originally used by native Americans to treat respiratory infections, was evaluated for its ability to stimulate the production of cytokines by normal human peripheral blood macrophages in vitro. Commercial preparations of echinacea fresh pressed juice and dried juice were tested at concentrations ranging from 10 micrograms/ml to 0.012 microgram/ml and compared to endotoxin stimulated and unstimulated controls. Cytokine production was measured by ELISA after 18 h of incubation for IL-1 and 36 and 72 h for TNF-alpha, IL-6, and IL-10. Macrophages cultured in concentrations of echinacea as low as 0.012 microgram/ml produced significantly higher levels of IL-1, TNF-alpha, IL-6 and IL-10 (P < 0.05) than unstimulated cells. The high levels of IL-1, TNF-alpha, and IL-10 induced by very low levels of echinacea are consistent with an immune activated antiviral effect. Echinacea induced lower levels of IL-6 in comparison to the other cytokines measured. These results demonstrate the immune stimulatory ability of the unpurified fresh pressed juice of Echinacea purpurea and offer some insight into the nature of the resulting immune response as compared to endotoxin.

Adjuvants, Immunologic↗
PubMed1996

Strong association of the third hypervariable region of HLA-DR beta 1 with autism.

We reported that the major histocompatibility complex (MHC) including the null allele of the C4B gene and the extended haplotype B44-C30-DR4 is associated with autism. We report now that the third hypervariable region (HVR-3) of certain DR beta 1 alleles have very strong association with autism. The HVR-3 of DR beta 1* 0401 or the shared HVR-3 alleles DR beta 1* 0404 and DR beta 1* 0404 and DR *0101, was expressed on extended haplotypes in 23 of 50 (46%) autistic subjects as compared to only 6 of 79 (7.5%) normal subjects. Another HVR-3 sequence, the DR beta 1* 0701 allele, was carried on extended haplotypes in 16 (32.0%) of the autistic subjects as compared to 8 (10.1%) of the normal subjects.

Alleles↗
PubMed1995

Is decreased blood plasma concentration of the complement C4B protein associated with attention-deficit hyperactivity disorder?

OBJECTIVE: The complement system is a group of blood proteins that play an important role in defending against viral and bacterial infections. The objective of this investigation was to study the plasma levels of the C4B protein in attention-deficit hyperactivity disorder (ADHD) in an attempt to associate infections with the development of some cases of this disorder. METHOD: C4B plasma protein levels were studied using an enzyme-linked immunosorbent assay in a group of 23 subjects meeting DSM-III-R criteria for ADHD and a similar number of age- and sex-matched controls. Also studied were parents of the ADHD subjects. RESULTS: C4B plasma levels (157.0 micrograms/mL) in the ADHD subjects were significantly (p < .01) lower than those (239.3 micrograms/mL) in the normal age-matched subjects. Mothers of the ADHD subjects also had significantly lower C4B values compared with mothers of normal children. On the other hand, C4B values in the fathers were not significantly altered. CONCLUSIONS: Decreased C4B levels in ADHD, if replicated, may represent an important marker for ADHD (or a subgroup of ADHD). It also seems plausible that C4B levels are an important etiological factor for ADHD.

Adolescent↗
PubMed1995

Increased frequency of the extended or ancestral haplotype B44-SC30-DR4 in autism.

Autism likely results from several different etiologies or a combination of pathological mechanisms. Recent studies suggest that this disorder may be associated with immune abnormalities, pathogen-autoimmune processes and perhaps the major histocompatibility complex (MHC). In a preliminary study we found that 22 autistic subjects had an increased frequency of the extended or ancestral MHC haplotype B44-SC30-DR4. The current study attempted to confirm this observation by studying 23 additional randomly chosen autistic subjects, most of their parents and 64 unrelated normal subjects. In agreement with earlier findings B44-SC30-DR4 was associated with autism. In combining the data from the original and current studies, B44-SC30-DR4 or a substantial fragment of this extended haplotype was represented in 40% of the autistic subjects and/or their mothers as compared to about 2% of the unrelated subjects. It is concluded that one or more genes of the MHC is (are) involved in the development of some cases of autism.

Autistic Disorder↗
PubMed1994

Decreased plasma concentrations of the C4B complement protein in autism.

OBJECTIVE: To determine complement C4 protein concentrations in the plasmas of autistic subjects and their family members. DESIGN: Cross-sectional study. SETTING: Center for Persons with Disabilities and the Department of Biology, Utah State University, Logan. PARTICIPANTS: Forty-two autistic subjects (34 males [81%] and eight females [19%]), 50 of their biologic parents, 21 siblings, and 105 normal subjects (56 females [53%] and 49 males [47%]; all white) living in northern Utah. INTERVENTIONS: None. METHODS: The enzyme-linked immunosorbent assay was used to determine C4 protein concentrations in autistic subjects. MAIN RESULTS: Plasma concentration (median, 14.7 g/L of the C4B protein) in autistic patients was significantly (P = .01) decreased compared with that of normal subjects (median, 22.4 g/L). The C4B concentrations in parents and siblings of autistic children were decreased, but not significantly. The C4A protein concentrations in the plasma of autistic subjects and their family members were normal. CONCLUSION: Decreased protein concentrations of C4B may be associated with autism.

Adolescent↗
PubMed1994

Life-threatening arrhythmias and RV dysfunction after surgical repair of tetralogy of Fallot. Comparison between transventricular and transatrial approaches.

BACKGROUND: Late postoperative arrhythmias and right ventricular dysfunction may occur after classic repair of tetralogy of Fallot. METHODS AND RESULTS: During a mean follow-up of 8.9 years (range, 5 to 14 years), 24-hour ambulatory electrocardiographic studies were done in 107 patients after repair of tetralogy of Fallot. Radionuclide angiography was performed in 97, and 78 patients also underwent postoperative heart catheterization. The patients were divided into two groups: group A consisted of 71 patients aged 2 months to 61 years (mean, 6.8 years) in whom the right ventricular approach was used; group B included 36 patients aged 8 months to 39 years (mean, 7.9 years) whose repair was through the right atrium. A transannular patch was employed in 42 (59.2%) patients in group A and in 23 (63.9%) patients in group B. Eighteen patients were adults (> 18 years old) at the time of surgery: 13 (18.3%) in group A and 5 (13.8%) in group B. During a mean follow-up of 9.7 years, 57 (80.3%) group A patients were in New York Heart Association (NYHA) functional class I. Atrial flutter was present in 3 (4.2%) patients, and 28 (39.4%) had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative heart catheterization showed good hemodynamic results in 36 of 54 group A patients studied (12 of whom had ventricular arrhythmias); moderate-to-severe pulmonary regurgitation was present in 14 (25.9%) patients; only 2 (3.7%) patients had right ventricular hypertension. On electrophysiological study, 8 of 28 (28.6%) patients in group A had inducible sustained ventricular tachycardia. Despite antiarrhythmic therapy, 2 of these patients died suddenly, presumably from ventricular arrhythmias. Two other late deaths in group A were caused by heart failure. During a mean follow-up of 7.2 years, 33 of 36 (91.7%) patients in group B were in NYHA functional class I. Atrial flutter was not found in any patient in this group. Only 1 (2.8%) patient, who had moderate-to-severe pulmonary regurgitation, had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative catheterization showed good hemodynamic results in 20 of 24 patients; 3 (12.5%) had moderate-to-severe pulmonary regurgitation, and 1 (4.2%) patient had right ventricular hypertension. Sustained ventricular tachycardia could not be induced in any of the 5 adult patients who underwent electrophysiological studies. One late death (caused by endocarditis) occurred in group B. CONCLUSIONS: The right atrial approach significantly reduced the risk of life-threatening ventricular arrhythmias after repair of tetralogy of Fallot (P < .001) without increasing the incidence of supraventricular arrhythmias. Right ventricular dysfunction and severe pulmonary regurgitation were also more prevalent (P < .01) when the right ventricular approach was used.

Arrhythmias, Cardiac↗
PubMed1993

Repair of interrupted aortic arch with an augmented aortic anastomosis.

In cases of interrupted aortic arch type A, the end-to-end aortic anastomosis can be enlarged with a left subclavian flap. In type B interruption, the divided left carotid artery is anastomosed to the distal aorta, and the anastomosis can be augmented with a reversed left subclavian flap. These techniques provide a tension-free, much wider, and noncircumferential anastomosis with potential for growth. Using a combined lateral and anterior approach, the duration of circulatory arrest for the intracardiac repair is minimized.

Anastomosis, Surgical↗
PubMed1993

Differential effect of footshock stress on humoral and cellular immune responses of the rat.

Recent, mostly "in vitro", studies indicate that certain stress protocols may affect differentially immune mechanisms. In agreement with these studies, our "in vivo" results show that 4 consecutive days of intermittent footshock, in rats, depressed the primary antibody response, to a thymic dependent antigen, but enhanced the graft-versus-host response and the capacity to reject an inocula of Walker carcinoma cells. Thus it is concluded that footshock stress is capable of oppositely affecting "in vivo" produced humoral and cellular immune responses.

Analysis of Variance↗
PubMed1993

Surgical management of the scimitar syndrome: an age-dependent spectrum.

Fourteen patients with scimitar syndrome, aged from 4 days to 20 years, underwent surgical treatment between September 1980 and August 1988. Patients were separated into two groups. Group A comprised four neonates with heart failure and severe pulmonary hypertension; part of the right lung was supplied by large aberrant systemic subphrenic arteries (ASSAs) in each. Group B included ten patients (nine children and one adult) with mild to moderate symptoms, normal pulmonary artery pressures; only two had ASSAs. In group A, one neonate with multiple ventricular septal defects underwent pulmonary artery banding but later required a lobectomy because of a lung abscess. The other three neonates underwent ligation of ASSAs; two improved rapidly, and one died of sepsis. In group B, all patients survived intracardiac repair and remain asymptomatic during a follow-up of 24 to 108 (mean 54.9) months. In summary, prognosis after intracardiac repair is excellent in patients without pulmonary hypertension. Neonates with heart failure usually improve after ligation of ASSAs, and pulmonary resection is only indicated in patients with intractable pulmonary sequestrations.

Adolescent↗
PubMed1993

Ventricular tumors: surgical options.

Primary cardiac tumors of the ventricles are very uncommon. During an 8-year period only, nine such patients were encountered: the tumor was primarily in the right ventricle in six, in the left ventricle in two and biventricular in one. There were seven children and two adults in this series. Histologically, the neoplasm was benign in all patients. The tumor was obstructive in six patients, five of whom underwent surgery (complete resection in three, partial excision in one and a Fontan-Kreutzer procedure in one); one neonate died before an operation could be performed. In addition, one patient with an epicardial tumor underwent complete resection. There were no early or late deaths among the six patients treated surgically. The tumor was small and non-obstructive in two patients, who were not operated on: one died suddenly, and the other was followed without intervention. In summary, complete or partial excision of ventricular neoplasms can usually be accomplished with good long-term results. If resection is not possible, effective palliation may be achieved with a Fontan-type operation, excluding the right ventricle from the circulation.

Adult↗
PubMed1993

Combined transaortic-transpulmonary approach for surgical repair of aortic insufficiency associated with ventricular septal defect.

Between September 1980 and August 1988, 21 patients, of mean age 7.3 (range 1-19) years, with ventricular septal defect and aortic valve prolapse, underwent surgery. Aortic insufficiency was mild in three patients, moderate in 13 and severe in five. Surgical repair was performed using a combined transaortic and transpulmonary approach. The prolapsed leaflets were evaluated through the ventricular septal defect before and after valvuloplasty. Using the Trusler technique, the prolapsed cusps were plicated at the level of the commissures; only one patient required aortic valve replacement. After functional assessment of the valve repair, through the ventricular septal defect, during infusion of cardioplegia in the aortic root, the defects were closed through the pulmonary artery, or through a right atriotomy. Mean follow-up was 51.5 (range 3-108) months. One patient developed bacterial endocarditis and died 3 months after surgery. The other 20 patients remained symptom-free. There are no residual ventricular septal defects, and mild residual aortic insufficiency is present in six patients. The mean(s.d.) cardiothoracic ratio decreased from 0.61(0.07) before to 0.49(0.05) after surgery. In summary, preservation and repair of the prolapsed aortic valve is possible even in the presence of severe aortic insufficiency. The combined approach through both great arteries enables good visualization with minimal traction, and accurate assessment of the aortic valvuloplasty through the ventricular septal defect. In addition, problems associated with a right ventriculotomy are avoided.

Adolescent↗