Search PubMed⌕ Search

Biomedical subjects

J R Torres

Publications and source records attributed to J R Torres.

At least 19 recordsLinked to original sources
PubMed2003

Low-grade parasitaemias and cold agglutinins in patients with hyper-reactive malarious splenomegaly and acute haemolysis.

A cluster of 16 cases of hyper-reactive malarious splenomegaly (HMS) with severe, acute haemolysis, from an isolated, Venezuelan, Yanomami population, was prospectively investigated. Nine (69%) of the 13 HMS sera investigated but only one (7%) of 14 control sera (P < 0.005) contained elevated titres (of at least 1:32) of complement-fixing IgM cold agglutinins (CA). The CA detected had specificity for both the I and i blood-group antigens (with a relative predominance of anti-I) and wide thermal stability. The mean reciprocal CA titre was much higher for the HMS sera than for the control samples (59.16 v. 2.28; P < 0.001). Indirect tests for antiglobulin were positive for two of the 13 HMS cases (but none of 14 controls) investigated; all of the direct tests for antiglobulin gave negative results. The seven HMS cases checked, using an assay based on a nested PCR which amplified species-specific ribosomal sequences from Plasmodium vivax or P. falciparum, each yielded the PCR product that indicated P. vivax infection. However, only six (25%) of the 24 control samples (collected, at the same time as the HMS samples, from asymptomatic adults from the same Yanomami population) were PCR-positive (P < 0.001). In some cases at least, the acute severe episodes of haemolysis occasionally seen in HMS appear to be associated with an auto-immune, cold-agglutinin-mediated response triggered by non-patent parasitaemias.

Adult↗
PubMed2002

Six years of experience in laparoscopic surgery of esophageal achalasia.

BACKGROUND: We show the experience of 6 years in laparoscopic surgical therapy of esophageal achalasia, performing of the Heller-Dor or Heller-Toupet operation, with particular regard to the technical aspect. METHODS: One hundred and ten laparoscopic interventions were done between November 1995 and December 2001. We studied operative time in hiatus approach, esophagocardiomyotomy, transoperative endoscopy, and anti-reflux procedure. We also analyzed the relation between complications and clinical evolution of disease with clinical stage. RESULTS: The mean surgical time of the intervention is 138 min, and it is significantly increased by transoperative endoscopic control; conversion to open surgery was not necessary. Clinical results are classified as excellent in 103 patients. Morbidity was 6%. CONCLUSION: This surgical procedure is a first line in the treatment of esophageal achalasia. It is necessary to have special care in early diagnostic cases to avoid electrosurgical injury.

Adolescent↗
PubMed2000

Leptospirosis in Latin America.

Leptospirosis is a common disease in Latin America. Transmission to humans occurs by contact with water or soil contaminated with the urine of rodents, dogs, or livestock. Pathogenesis is still poorly understood, and bacterial toxin or virulence factors are probably responsible for many features of the disease. The anicteric form is the most frequent presentation, and its clinical picture resembles influenza or other acute febrile diseases. Icterohemorrhagic leptospirosis, or Weil's syndrome, represents the severe form of the disease. Its clinical picture is similar to bacterial sepsis and multiple organ involvement occurs, mainly in kidneys and lungs, and causes great morbidity and mortality. Death is often related to multiple organ failure and pulmonary hemorrhages. Diagnosis is based on serology or blood, cerebrospinal fluid and urine cultures in specific media. Treatment involves a combination of antibiotics and supportive measures.

Animals↗
PubMed2000

Acute parotitis due to dengue virus.

Acute bilateral parotitis is a common clinical feature of various infectious and autoimmune, metabolic, and drug-related conditions. We describe a unique case of bilateral inflammatory enlargement of the parotid glands in an immunocompetent patient with dengue fever. Evidence of dengue virus in the saliva is also provided for the first time.

Acute Disease↗
PubMed1999

Role of physician assistants in dialysis units and nephrology.

We surveyed physician assistants who work in nephrology to report their experience level, primary employer, salary, job responsibilities, and job satisfaction. Additional data were obtained from the Nephrology Manpower Study. The 67 responding physician assistants of 97 surveyed have 10.8 +/- 6.5 years (mean +/- standard deviation) total experience (6.2 +/- 5.0 years in nephrology). Typically, nephrologists (56.1%) or hospitals (30.3%) employ them. The majority (74%) earn $49,999 to $75,000; 79.1% work in outpatient units, 52.4% in inpatient units, 52.4% in hospitals, 43.3% in outpatient offices, and 23.9% in transplant units. In outpatient units, they manage 111 +/- 111 patients, mostly in free-standing (71.1%), for-profit (69.7%), corporately owned (87.3%) units in urban (80%) or suburban (18%) areas. Most (>85%) manage all dialysis- and nondialysis-related problems, including health maintenance; 84.3% are contacted first by staff, and 78% see patients more often than physicians. Of nephrologists who responded to the Manpower Study, 8.9% work with physician assistants and 20.7% work with nurse practitioners. Nephrologists in academic practice or private nephrology groups are more likely to use physician assistants (P < 0.05) and nurse practitioners (P < 0.005) than those in solo practice or multispecialty groups. Nephrologists with physician assistants (33.8 +/- 19.5 v 41.7 +/- 16.8 h/wk) or nurse practitioners (35.8 +/- 18.1 v 42.7 +/- 16.9 h/wk) tended to spend less time in direct patient care than those without physician extenders (P < 0.001). Nephrologists with renal fellows, however, spent the least time of all in direct patient care (30.0 +/- 15.9 v 47.3 +/- 14.9 h/wk; P < 0.001). Physician assistants can perform nearly all the medical tasks in dialysis units. They may offer one approach to providing effective and complete care for patients if nephrology manpower becomes limited.

Hemodialysis Units, Hospital↗
PubMed1998

Antigenic diversity of hepatitis B virus strains of genotype F in Amerindians and other population groups from Venezuela.

The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.

Amino Acid Substitution↗
PubMed1996

Hepatitis B and hepatitis delta virus infection in South America.

About 100,000 cases of acute hepatitis B virus (HBV) infection occur annually in South America. The overall prevalence of HBV infection in low risk populations ranges from 6.7% to 41%, while hepatitis B surface antigen (HBsAg) rates range from 0.4% to 13%. In high endemicity aboriginal or rural populations, perinatal transmission may play a major part in the spread of HBV. In urban populations, however, horizontal transmission, probably by sexual contact, is the predominant mode of spread, with higher rates of HBV positivity in lower socioeconomic groups. High risk populations such as health care workers and haemodialysis patients show higher rates of HBV infection than comparable populations elsewhere. The risk of posttransfusion hepatitis B remains high in some areas. Concomitant HBV infection may accelerate the chronic liver disease seen in decompensated hepatosplenic schistosomiasis. In the north, the prevalence of hepatitis delta virus (HDV) infection ranks among the highest in the world. In the south, the problem appears negligible although it is increasing within high risk urban communities. HDV superinfection has been the cause of large outbreaks of fulminant hepatitis. The cost of comprehensive or mass vaccination programmes remains unaffordable for most South American countries. Less expensive alternatives such as low dose intradermal schedules of immunisation have been used with success in selected adult subjects.

Hepatitis B↗
PubMed1994

Depression, HIV dementia, delirium, posttraumatic stress disorder (or all of the above)

A 29-year-old single Puerto Rican woman with AIDS was admitted to the Medical Service for pneumonia, seen by the Psychiatric Consultation Service, an eventually transferred to the Inpatient Psychiatric Unit with several possible psychiatric diagnoses including major depression, HIV dementia, delirium, and posttraumatic stress disorder. These possibly coexisting and interacting syndromes are discussed by three psychiatrists, one of whom is also a board-certified neurologist. This case illustrates the combined contribution of organic and psychological factor to complex behavioral disorders, which are increasingly common in HIV infection.

AIDS Dementia Complex↗
PubMed1994

Salmonellal splenic abscess in the antibiotic era: a Latin American perspective.

Ten cases of salmonellal splenic abscesses recently documented in various Latin American countries are discussed. All patients were adults; the mean age was 32.6 years, and there was a predominance of males (seven). Predisposing conditions were identified in four cases. All 10 cases were documented by diagnostic imaging techniques; in one case, exploratory diagnostic laparotomy was also performed. Splenectomy was performed on eight patients, while two other patients responded to long courses of intravenous antimicrobial therapy alone. One patient died as the result of perioperative splenic rupture, and two patients underwent second laparotomies because of left subphrenic abscesses. Except for one human immunodeficiency virus-infected individual, all patients were immunocompetent and had large solitary lesions. Salmonella typhi was the predominant organism isolated and was recovered in six of the 10 cases.

Abscess↗
PubMed1994

Special aspects of hepatitis B virus and delta virus infection in Latin America.

Viral hepatitis is a common condition in Latin America. Central and South American countries report several thousand new cases of viral hepatitis each year. This article reviews the hepatitis B virus and hepatitis delta virus infections as major public health problems in Latin America. Their causes, symptoms, and special problems related to these strains of hepatitis are discussed in detail.

Hepatitis B↗
PubMed1993

Efficacy of ivermectin in the treatment of strongyloidiasis complicating AIDS.

Nine adult male homosexuals who were infected with the human immunodeficiency virus (five with AIDS-defining conditions) and harbored Strongyloides stercoralis received ivermectin on a compassionate basis for persistent intestinal infection. Hyperinfection was present in all cases. Ivermectin was given either as a single oral dose (200 micrograms/kg) or on a multidose schedule (200 micrograms/kg.d) on days 1, 2, 15, and 16. All seven patients who received multiple doses showed sustained clinical and parasitological cure, whereas one of two patients who received single-dose therapy relapsed promptly and fatally. Remissions have been maintained for at least 7 months and up to 3 years of follow-up. Ivermectin appears promising in the treatment of strongyloidiasis in patients with AIDS. Because of the risk of hyperinfection and/or disseminated disease, multidose courses are warranted. We are not aware of other reports describing the efficacy of antiparasitic drugs for strongyloidiasis in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1992

Maintenance of Sparganum proliferum in vitro and in experimental animals.

Successful in vitro and in vivo maintenance of Sparganum proliferum is described for the first time. Various experimental animals including hamsters, mice and a monkey were evaluated. Albino mice inoculated either subcutaneously or intraperitoneally allowed the survival and multiplication of larvae for as long as 72 weeks. Intensity of infection was proportional to the length of exposure; however, the number of larvae collected from inoculated animals varied widely when infection lasted for 6 or more months. Inoculation of single larval segments appears as effective as that of complete larvae. Although Minimal Essential Medium allowed the survival of S. proliferum for as long as 14 weeks, growth was observed only during the first 4 weeks of culturing. Despite initial in vitro growth of larvae, neither differentiation into a more developed stage nor multiplication was obtained.

Animals↗
PubMed1992

Multifocal Salmonella splenic abscess in a HIV-infected patient.

A case of spleen abscess complicating Salmonella bacteremia in a HIV-infected patient is reported for the first time. Chronic pancreatitis and the infection of a pre-existing pseudocyst of the pancreas tail might have been the predisposing factor. Infection developed before other AIDS criteria were evident in the patient. Splenectomy plus antibiotic therapy was required to eradicate the process. Salmonella enteritidis was cultured from two suppurated lesions of the excised organ.

Abscess↗
PubMed1989

Effect of priming with carrier on response to conjugate vaccine.

To examine whether prior immunity against a carrier protein modulates the serological response to injected peptide haptens attached to the same carrier in man, baseline tetanus antitoxin levels in volunteers who received a malaria sporozoite peptide-tetanus toxoid conjugate vaccine were compared with post-vaccination IgM and IgG antibody titres against the sporozoite antigen. In tetanus-vaccinated North American recipients of low doses of conjugate vaccine there were significant dose-dependent negative correlations between these variables, which suggests that epitopic suppression may occur in man. In contrast, Venezuelans living in non-malarious areas and mostly naive to tetanus toxoid showed a notable IgM response to the sporozoite antigen. The findings indicate that epitopic suppression and immune enhancement occur in man, and that the specific immunological responses to conjugate peptide vaccines may be difficult to predict.

Adjuvants, Immunologic↗