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Biomedical subjects

M Alvarez

Publications and source records attributed to M Alvarez.

At least 397 records · Page 22Linked to original sources

The diagnostic usefulness of a DNA probe for Mycobacterium tuberculosis complex (Gen-Probe) in Bactec cultures versus other diagnostic methods.

The combination of the radiometric Bactec system and the Gen-Probe for Mycobacterium tuberculosis complex (MTB) in detection and identification of mycobacteria was evaluated. Löwenstein-Jensen and Coletsos media for isolation, and Bactec-NAP test and cellular morphology and grouping for identification of MTB and mycobacteria other than tuberculosis (MOTT) were also evaluated. The study included all specimens submitted to our laboratory for mycobacteria detection over a 6-month-period. The mean recovery times of MTB were 13.7, 23.3, and 21.2 days for Bactec, Löwenstein-Jensen and Coletsos, respectively. Bactec system recovered 87.8% of MTB strains and 98% of MOTT, and the conventional media 82.9% of MTB and 19.2% of MOTT. Ziehl-Neelsen smears and Bactec-NAP were effective in differentiating MTB and MOTT strains (3.3% and 9.6% respectively of the cultures were uninterpretable). Gen-Probe (cutoff point for MTB = 5% of hybridisation) was applied to 100 positive vials of Bactec. All cultures of MTB with a growth index (GI) > 400 displayed hybridisation > 9% (average 28.9%) but for a GI < 400, 17% of cultures showed < 5% of hybridisation (average 18.6%). All cultures for MOTT had < 5% hybridisation. With the combination Bactec/Gen-Probe the average time of the final report could be reduced to 15.5 days.

DNA Probes↗

Nosocomial Kikuchi's disease--a search for herpesvirus sequences in lymph node tissues using PCR.

BACKGROUND: Histiocytic necrotizing lymphadenitis, also known as Kikuchi's disease (KD), is a rare disease. Fever and lymphadenopathies with characteristic pathologic features are present. The etiology of this disease remains undetermined. Since the disorder is self-limiting, different viruses have been implicated as the causative agent. PATIENTS AND METHODS: Seven cases of KD were studied. Three patients acquired the disease nosocomially, three had community-acquired KD and one case was associated with systemic lupus erythematosus. PCR was performed on DNA extracted from lymph node tissues in order to detect herpesvirus-specific DNA sequences: herpes simpLex virus type 1 and 2 (HSV1-2), varicella zoster virus (VZV), human cytomegalovirus (HCMV), human herpesvirus 6 (HHV6), Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV8). RESULTS: Viral DNA was not detected in any of the lymph node tissues from the seven cases of KD. CONCLUSION: We conclude that these herpesviruses were not involved in the etiology of the three cases of nosocomial KD, nor in the other four cases of KD investigated in this study.

Adolescent↗

BK virus (BKV) detection in urine specimens of immunocompromised patients: comparison between the DNA-DNA hybridization assay, the immunofluorescence test and the dot enzyme immunoassay.

Three methods used for the detection of BK virus in urine specimens, the indirect immunofluorescence test, the dot enzyme immunoassay and the DNA-DNA hybridization assay, were compared by testing specimens from 49 immunocompromised patients. All three assays were effective in detecting BK virus. The technical advantage of each of them was discussed. The immunofluorescence test was found to be the simplest one to perform; the DNA-DNA hybridization assay displayed exquisite sensitivity; and the easy reading of the dot enzyme immunoassay did not require the specialized training inherent to immunofluorescence assays. The dot enzyme immunoassay might therefore be the most practical method for screening urine specimens of immunocompromised patients, especially when the sediment is poor in cells. Conversely, the indirect immunofluorescence test might be the method of choice for checking patients with haemorragic cystitis whose urine samples usually contain large amounts of cells.

BK Virus↗

Enzyme-linked immunosorbent assay with a Salmonella enteritidis antigen for differentiating infected from vaccinated poultry.

The specificity and sensitivity of indirect ELISA, based on the use of four different antigenic extracts obtained from a clinical isolate of Salmonella enteritidis, were compared with those obtained with the gm-flagellin based ELISA (IDEXX). A total of 116 serum samples from salmonellae free, naturally infected and vaccinated hens were studied. The results showed that the indirect ELISA, based on lipopolysaccharide (LPS), O-polysaccharide (PS) or membrane sediment (SD) antigens, enable the identification of a greater number of infected birds and discriminated field antibody responses from vaccinal ones better than the commercial IDEXX test. The indirect ELISA that used a O-polysaccharide rich fraction (PS) proved to be the most specific and sensitive test, suggesting that this indirect ELISA could be used to confirm IDEXX results, especially when the differentiation between vaccinated and infected poultry is required.

Animals↗

Prophylactic and emergent arterial catheterization for selective embolization in obstetric hemorrhage.

Treatment of obstetric hemorrhage by the selective embolization of damaged pelvic vessels under fluoroscopy holds promise as an alternative to surgical intervention. Unfortunately, the effectiveness of selective embolization is often compromised by its use in emergent settings following the failure of primary operative approaches. Therefore we compared the efficacy of prophylactic versus emergent catheter placement for selective embolization in nine patients with or at risk for obstetric hemorrhage. In four patients with acute obstetric hemorrhage catheterization and embolization was carried out following the failure of initial medical and surgical approaches. In five patients determined to be at risk for intrapartum hemorrhage based on sonographic findings, catheters were inserted into the hypogastric vessels prior to elective cesarean delivery. Three of these five patients subsequently required selective embolization. In comparison to patients undergoing selective embolization following prophylactic catheter placement, patients in the emergent group all had a coagulopathy at the time of embolization, sustained substantially greater blood loss, and had an increased rate of postpartum complications. Finally, there was a significant reduction in total embolization time and therefore in radiation exposure in patients undergoing prophylactic catheter placement prior to selective embolization. These data support the conclusion that in patients determined to be at risk for intrapartum or postpartum hemorrhage the prophylactic placement of catheters allows for selective embolization in a hemodynamically intact patient with stable coagulation indices, theoretically reducing the risk of maternal morbidity and possibly mortality.

Adult↗

In vitro and in vivo effects of three bismuth compounds on fermentation by colonic bacteria.

Three bismuth compounds (tripotassium dicitrate bismuthate, bismuth subsalicylate, and bismuth subnitrate) were tested in vitro and in vivo for their effect on fermentation by colonic bacteria. The studies in vitro were done with use of a technique designed to determine the effect of each one of the bismuth compounds on the fermentation of several stool samples that had been mixed with lactose as additional fermentable substrate (fermentation of lactose-enriched stools, FLES). The three bismuth compounds reduced FLES significantly in 47 (81%) of 58 of the stool samples used to test their effect. Bismuth subsalicylate, which reduced FLES in 10 of 10 stool samples, showed the greatest reduction (mean reduction, 74%; P less than .0001). The in vivo studies, done in six flatulent patients, showed significant reduction (P less than .01) of colonic fermentation of ingested raffinose by oral bismuth subnitrate given for 8 days.

Adolescent↗

Catheter-related infections associated with home parenteral nutrition and predictive factors for the need for catheter removal in their treatment.

The inpatient and outpatient records were reviewed for 527 patients, including 138 children, who were discharged on home total parenteral nutrition and followed by the University of California, Los Angeles, home total parenteral nutrition service for a minimum of 1 week between April 1973 and October 1991. The total follow-up time was 1154 patient years; the median follow-up time was 206 days (range 7 to 6344 days). Thirty-six patients were followed for more than 10 years (median 12.7 years). Three hundred fifteen adults (but only four children) were never infected. A total of 427 catheter-related infections occurred, giving an overall infection rate of 0.37 per patient year (0.51 per patient year in children and 0.28 per patient year in patients followed for more than 10 years). Seventy percent of the infections overall were sepsis (0.26 per patient year); of those, 17% were exit site (0.06 per patient year), and 2% were tunnel (0.01 per patient year) infections. In children, 67% of the infections were sepsis (0.37 per patient year) and 24% were exit site (0.13 per patient year). Fifty-four different organisms were responsible, and 12% of the infections were polymicrobial in origin. Sixty percent of sepsis in all patients was caused by Gram-negative organisms (44% of the catheters were removed). Forty-three percent of sepsis in children was caused by Gram-negative organisms. Twenty-six percent of sepsis in all patients was caused by Gram-positive organisms (40% of the catheters were removed). Thirty-six percent of sepsis in children was caused by Gram-positive organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Candidiasis↗

Thyroid hormone and attention in congenital hypothyroidism.

OBJECTIVES: To determine in school-age children with congenital hypothyroidism: (i) frequency of a high thyroxine/high thyrotropin profile; (ii) relations between different levels of thyroxine and thyrotropin and attentional function, and (iii) persistence of effects. DESIGN: Retrospective analysis of an inception cohort. SETTING: Clinical psychology laboratory in tertiary pediatric hospital. SUBJECTS: Eighty-six 7 year olds identified with congenital hypothyroidism by newborn screening, who were participating in a long-term prospective study. MAIN OUTCOME MEASURES: Wechsler Intelligence Scale for Children-Revised (WISC-R) and Wide Range Achievement Test-Revised (WRAT-R) were administered. WISC-R Full Scale, Verbal and Performance IQs were obtained as well as scores on individual subtests, and three ability composites. Freedom from Distractibility (FFD) served as the indicator of attention. RESULTS: 9.3% of 7 year olds had elevations of both T4 and TSH. These children scored significantly higher on word knowledge and spelling but had significantly lower Digit Span and FFD scores than those in groups with other hormone combinations. Level of thyroxine was the primary predictor of attention, accounting for 10.5% of the variance. Among 9 year olds, 6.1% had T4 and TSH elevations, and although they also scored lowest on FFD, these were not the same children with T4 and TSH elevations at age 7. CONCLUSIONS: These results signify that a high T4/high TSH profile contributes to poorer attention. Because the individual children who showed the effect were not the same at the two ages, this suggests that thyroid hormone appears to play a role in regulating attention but does not indicate resistance.

Achievement↗

Attentional processing in hyperthyroid children before and after treatment.

To determine whether specific components of attentional processing may be differentially disrupted during thyrotoxicosis, nine children with hyperthyroidism were assessed for intelligence and attention before and after one year of therapy. The attention test allowed for measurement of sustain, disengage, and shift subcomponents of attentional processing. Comparison with pediatric controls revealed lower nonverbal intelligence during thyrotoxicosis, which improved to normal following euthyroidism. On the attention task, an effect was observed during thyrotoxicosis only on the shift and disengage functions of attentional processing but not sustain. Attention results were unrelated to self-reported anxiety at time of testing. Results are discussed in terms of thyroid hormone activation of the prefrontal cortex, which is thought to be the cerebral substrate underlying the shift and disengage functions of attentional processing.

Anxiety↗

Hepatic fascioliasis: case report and review.

A well documented case of hepatic fascioliasis (HF), successfully treated with triclabendazole, is reported. Predominant clinical manifestations were fever, marked eosinophilia and abdominal pain. Triclabendazole was given as two single oral doses of 10 mg/kg each. Neither side effects nor clinical or parasitological relapses were seen after three months of follow up. Based on this experience and few other similar reports in the literature, triclabendazole might be a valid therapeutical alternative in the treatment of human fascioliasis.

Administration, Oral↗

[Rapid diagnosis of cytomegalovirus in immunocompromised patients using monoclonal antibodies that detect early viral antigens].

A technique was applied to detect early fluorescent antigens (DEFA) of cytomegalovirus (CMV) using the E13 monoclonal antibodies in 52 immuno-compromised patients hospitalized in the Nephrology Institute of Havana. Of the 75 urine or blood (buffy coat) samples taken, 15 were found positive to CMV. Using classical diploid human fibroblast isolation technique, 12 CMV strains were isolation of previously detected positive samples by DEFA. In addition, CMV was isolated from one sample reported to be negative by DEFA. A coincidence of 80% was found between both techniques. With the ELISA test, all the sample studied have IgG antibodies to CMV.

Adolescent↗

Detection of cytomegalovirus in urine of HIV-infected patients by DNA-DNA hybridization comparison with virus isolation, immunofluorescence and immunoperoxidase.

Immunofluorescence and immunoperoxidase test directed against early viral antigens, and DNA-DNA hybridization were compared with viral isolation for their abilities to detect Cytomegalovirus (CMV) in the urine of 89 HIV infected patients. From the 100 urine samples collected, 70 were found positive by at least one method. Considering viral isolation as the "gold standard" technique, immunofluorescence and immunoperoxidase had a sensitivity of 92.3% and 88% respectively, with a specificity in both cases of 95%. DNA-DNA hybridization showed a sensitivity of 90% but with lower (60%) specificity. All of the three assays were effective in detecting CMV from urine and the technical advantage of each is discussed.

Antibodies, Viral↗

[Economic and social impact of the National Tuberculosis Control Program (NTCP) on the Cuban population].

Tuberculosis (TB) control strategies provide one of the greatest cost/effectiveness results. To assess the impact of the national TB control program on the Cuban population, the time series of new TB cases and death reports, potential years of life lost, and the numbers of beds for TB case hospitalization in the entire country during 1964-91 and 1992-96 were described by common simple calculation on the basis of estimated expected values. The reduction in new TB cases and deaths, potential years of life saved, and savings in expenditures for treatment, hospitalization, and unemployment compensation were estimated. From 1965 to 1991 new case reports were reduced by 94.6% (4% per year); 86,500 cases were avoided; 166,439 potential years of life were saved; 2,831,625 million pesos were saved on tuberculostatic drugs; 82.7 million pesos were saved on unemployment compensation under the social security system for workers with active TB. Estimated savings totaled 494,919,631.3 pesos. Nationwide intervention for TB control produced an important impact on the basis of the sociopolitical status making it possible to approach complete elimination of the disease in the future.

Cost-Benefit Analysis↗