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Biomedical subjects

M L Kumar

Publications and source records attributed to M L Kumar.

At least 37 records · Page 2Linked to original sources

A prospective randomized double-blind study to evaluate the effect of dexamethasone in acute laryngotracheitis.

To determine whether a single dose of dexamethasone (0.6 mg/kg) is useful in the treatment of acute laryngotracheitis (croup), 29 hospitalized patients with acute laryngotracheitis were randomly assigned in a double-blind fashion to receive either parenterally administered dexamethasone (n = 16) or a saline placebo (n = 13). Severity of the illness was assessed by a clinical croup score based on retractions, stridor, air entry, cyanosis, and level of consciousness. Twelve hours from the time of injection, the patients receiving the dexamethasone had a statistically significant decline in median croup score from 4.5 to 1.0 (p less than 0.001), whereas the patients receiving the placebo did not. By 24 hours, a decline of two or more points in the total croup score was noted in 85% of the patients in the dexamethasone group compared with 33% of the patients in the placebo group (p = 0.027). During this same period, only 19% of patients receiving dexamethasone required two or more racemic epinephrine treatments in comparison with 62% of patients who received the placebo (p less than 0.05). There was no statistical difference between the two groups in improvement in oxygen saturation, respiratory rates, or duration of hospitalization. We conclude that dexamethasone is beneficial in reducing the overall severity of moderate to severe acute laryngotracheitis during the first 24 hours after injection.

Acute Disease↗

Rapid detection of respiratory syncytial virus by a biotin-enhanced immunoassay: test performance by laboratory technologists and housestaff.

A biotin-enhanced enzyme immunoassay (EIA) for respiratory syncytial virus (RSV) antigen detection (TESTPACK RSV) was prospectively compared with virus isolation in cell culture and immunofluorescence. Of 156 nasopharyngeal swab specimens from infants with respiratory symptoms, 81 (52%) yielded RSV in culture. Compared with culture the sensitivity of the EIA was 95% and specificity was 92%; the specificity increased to 97% with a blocking assay. Compared with immunofluorescence the sensitivity of EIA was 92% and specificity was 93%. In order to assess the performance of TESTPACK RSV as a bedside test, nasopharyngeal swabs from 49 children were tested by EIA at the bedside by housestaff and by immunofluorescence in the laboratory; the sensitivity of the EIA was lower (78%) while specificity remained high (95%). Inclusion of older children may have resulted in diminished sensitivity. The TESTPACK RSV is a simple, rapid test that performs well and is easily adaptable to an office setting. Further evaluation of the test in older children may be required.

Biotin↗

Rapid diagnosis of common sexually transmitted diseases in adolescents: a review.

Sexually transmitted diseases (STDs) represent a significant health problem for adolescents in the United States. As a result, clinicians from a number of disciplines, among them pediatrics and dermatology, may be called on to evaluate teenage patients with these infections. Traditionally, the diagnosis of many STDs has relied on isolation of the causative organisms in culture. While such procedures typically offer optimal diagnostic accuracy, they are often time consuming and expensive, and may not be widely available. In an attempt to remedy this, culture-independent techniques have been developed to permit more rapid and economical diagnosis of these important pathogens. The strengths and limitations of these methods must be understood, however, for the tests to be used effectively.

Adolescent↗

Humoral immunity and clinical reinfections following varicella vaccine in healthy children.

The duration of immunity following varicella-zoster vaccination in healthy children remains a critical issue. In a 3-year study of 140 OKA/Merck vaccine recipients, duration of immunity was assessed by two measures. The first was persistence of varicella-zoster antibody measured by modified fluorescent antibody to membrane antigen test. Thirty-six toddler vaccinees 12 to 24 months of age had sera obtained at 6 weeks, 1 year, and 2 years. Geometric mean titer +/- SD at 6 weeks was 57.7 +/- 2.9; at 1 year, it was 12.4 +/- 3.9; at 2 years, it was 9.9 +/- 3.9. Repeated-measures analysis of variance showed a significant overall decrease in antibody titer with time (F = 30.62, P less than .001). Post hoc comparisons indicated that the 6-week and 1-year titers were significantly different (P less than .001), but the difference between 1 and 2 years was not (P = .138). Clinical reinfections were also examined for 3 years after vaccination. Suspected varicella cases were confirmed by a fourfold or more increase in titer. Of 84 toddlers, 68 were exposed one or more times, and 6 became reinfected. Of 49 siblings, 45 were exposed, and one became reinfected. All 7 children had less than 70 vesicles and 6 of 7 were afebrile. No cases of zoster occurred. It is concluded that OKA/Merck varicella-zoster vaccination leads to antibody persistence for 2 years and the few reinfections that do occur are greatly attenuated.

Antibodies, Viral↗

Use of enzyme immunoassay for the rapid diagnosis of Chlamydia trachomatis endocervical infection in female adolescents.

Enzyme immunoassay (EIA) has been proposed as an alternative to tissue culture for the detection of Chlamydia trachomatis in cervical specimens. The diagnostic efficacy of EIA was compared to tissue culture in 113 teenaged females attending an adolescent reproductive health program. Infection was diagnosed by tissue culture in 16% of subjects. Compared with tissue culture, EIA demonstrated a sensitivity of 100%, specificity of 88%, positive predictive value of 62%, and a negative predictive value of 100%. These data indicate that EIA is an acceptable alternative to tissue culture when screening for C. trachomatis endocervical infection in adolescent females.

Adolescent↗

Risk of adverse outcomes of pregnancy after human parvovirus B19 infection.

Human parvovirus B19 (B19) infection during pregnancy has been associated with fetal deaths. We conducted several studies to develop data needed to make recommendations for preventing fetal death associated with infection. In the first study, after an outbreak of B19 infection, specimens of cord blood from 47 infants with congenital anomalies, 10 with suspected intrauterine infection, and gestational age-matched controls were tested for IgG and IgM antibodies to B19. None had evidence of recent infection. Next, 192 women with unknown exposure to B19 who had stillbirths or spontaneous abortions were studied. Two patients and two controls had evidence of recent B19 infection. In a second case-control study of women who had stillbirths after outbreaks of erythema infectiosum in area schools, none of the 20 patients or 26 controls were IgM positive at the time of delivery. The rate of infection, as demonstrated by IgM positivity, among 267 pregnant control subjects was approximately 1%. These studies suggest that among pregnant women unselected for exposure to B19, neither infection nor stillbirths are common.

Antibodies, Viral↗

Live attenuated varicella vaccine in healthy 12- to 24-month-old children.

We studied live attenuated Oka/Merck varicella vaccine in 147 seronegative children 12 to 24 months of age and their 94 seronegative older siblings 2 to 12 years of age. The vaccine side effects were mild, consisting of a papular rash in 15 of 147 (10.2%) children 12 to 24 months and seven of 94 (7.4%) siblings. In a subset of 12- to 24-month-old children, modified fluorescent antibody test for membrane antigen was not detectable at seven days postimmunization but was detectable in 50% by 14 days and in 100% by 21 days. Within 6 weeks, 96.6% of children 12 to 24 months and 94.7% of siblings seroconverted. The geometric mean titer did not vary with age at immunization. One-year blood samples were obtained from 70 children 12 to 24 months of age who seroconverted; 92.9% retained detectable antibody. The geometric mean titer had decreased from 55.7 to 18.6. Of these 70 children, 34% had been exposed to varicella since immunization, and two cases of varicella were observed in seroconverters. Both cases were mild, with less than 50 vesicles. Oka/Merck varicella vaccine appears to be safe, highly immunogenic, and protective against 96% of exposures to natural varicella during the first year after vaccination in infants. Those cases of varicella that develop in immunized children appear substantially reduced in severity.

Antibodies, Viral↗

Should we expand the TORCH complex? A description of clinical and diagnostic aspects of selected old and new agents.

Physicians faced with a newborn infant with signs and symptoms of perinatal infection must consider a multitude of diseases, and may need to embark on a complex differential diagnosis. As stated by Alford in 1967, "neonatal diagnoses of infections acquired in utero, natally and postnatally, are inherently difficult." Twenty years later, this statement is still true. In this review, the diagnostic problems encountered in the evaluation of a suspected perinatal infection have been discussed, as have the complexities of the evaluation process for the original four TORCH agents, as well as for three additional agents. From our point of view, the usefulness of the TORCH acronym has been to focus attention on perinatal infections. Its main drawback has been the resultant overuse of TORCH titers ignoring the complexity of the diagnostic process. Ideally, the TORCH concept serves two functions. It continues to remind us of the multiplicity of pathogens that can cause perinatal infection, and it underscores the need for thorough diagnostic evaluation for these challenging infections. We believe that this is an appropriate expansion of the TORCH complex, and we anticipate that this expanded TORCH complex will continue to grow.

Acquired Immunodeficiency Syndrome↗

Bladder fungus ball: a reversible cause of neonatal obstructive uropathy.

Very low birth weight infants often have multiple predisposing conditions for the development of invasive candidiasis. In patients with systemic candidiasis, the kidney is vulnerable to the formation of cortical abscesses or obstructive intrarenal masses ("fungus balls"), usually at the ureteropelvic junction. Ureteropelvic junction obstructive fungal uropathy necessitates invasive debridement to restore renal function. A very low birth weight infant, infected with Candida, was first seen with hypertension, renal insufficiency, and urine cultures positive for fungus; obstructive bladder fungus ball was diagnosed by ultrasonography. Mechanical disruption with amphotericin B bladder irrigation was accomplished via ultrasonographic guidance, relieving renal obstruction and insufficiency. Systemic antifungal therapy was completed with amphotericin B and flucytosine. The first reported case of bladder obstructive fungal uropathy in a neonate is added to a review of 16 cases of neonatal renal obstructive uropathy.

Administration, Intravesical↗

Diagnostic efficacy of two rapid tests for detection of respiratory syncytial virus antigen.

With the availability of ribavirin therapy for serious respiratory syncytial virus (RSV) infections, rapid diagnostic tests for the detection of RSV antigen are increasingly important. Efficacies of a commercially available enzyme immunoassay (EIA) (Abbott Laboratories, North Chicago, Ill.) and a fluorescent-antibody assay (FA) were evaluated in a study involving 135 specimens from children with respiratory symptoms. A nasal wash specimen was cultured immediately on RSV-sensitive A549 cells; the nasal wash was also used for EIA. FA was performed on a nasopharyngeal swab specimen with bovine anti-RSV and anti-bovine immunoglobulin G antisera (Burroughs Wellcome Co., Research Triangle Park, N.C.). A total of 39 specimens (28%) were tissue culture positive, including 35 EIA-positive and 37 FA-positive samples (sensitivities, 90 and 95%, respectively). All 96 tissue culture-negative specimens were EIA negative (specificity, 100%); 94 of these 96 specimens were FA negative (specificity, 98%). Positive and negative predictive values for the tests were as follows: 100 and 96% for EIA, respectively, and 95 and 98% for FA, respectively. Other viruses, including influenza A virus, adenovirus, enterovirus, and herpes simplex virus, were isolated in nine cases. One adenovirus-positive specimen had a false-positive RSV FA result; all nine specimens were RSV EIA negative. Both tests performed well in our study and provide cost-effective alternatives to tissue culture. The RSV EIA, in particular, uses standard serologic techniques and equipment and does not require expertise in virology. More widespread availability of rapid diagnostic tests for RSV will hopefully result in early and appropriate use of antiviral therapy in patients at risk for serious RSV infections.

Antigens, Viral↗

Should all pregnant women be screened for hepatitis B?

To assess the sensitivity of historical risk factors for identification for hepatitis B surface antigen (HBsAg)-positive parturients, 4399 pregnant women were consecutively screened for HBsAg. Information regarding risk for hepatitis B infection was obtained from each HBsAg-positive parturient. Twenty-three HBsAg-positive subjects were identified (5.2/1000 deliveries). The HBsAg carrier rate (18/2231, or 8.1/1000 deliveries) was significantly higher in women of black, Asian, or Hispanic origin than in the remaining ethnic groups (non-Hispanic whites plus all others, 5/2168, or 2.3/1000 deliveries) (chi square, 5.95; p = 0.016). Risk factors for identification of HBsAg-positive women were present in 10 of 22 asymptomatic subjects (sensitivity, 45%; 95% confidence interval, 24% to 68%). Much of the information required to assess one of these risk factors, previous infection, involved detailed questioning and is unlikely to be obtained in the context of conventional obstetrical care. Routine maternal HBsAg screening programs may be needed if transmission of hepatitis B from mother to infant is to be prevented.

Carrier State↗

Evaluation of clinical specimens for the presence of respiratory syncytial virus antigens using an enzyme immunoassay.

An enzyme-linked immunoassay (EIA) was developed for the detection of respiratory syncytial virus (RSV) antigen in nasopharyngeal secretions. This assay, which employs goat and rabbit anti-RSV as the capture and detector antibodies respectively, was used in a retrospective evaluation of frozen clinical specimens from children. The EIA results were compared with those of virus isolation in cell culture and direct fluorescent antibody staining performed at the time of specimen collection. The sensitivity of the RSV EIA compared to cell culture was 91.3% (63/69) with a specificity of 96.8% (93/96). The predictive value of a positive EIA result was 95.4% and for a negative EIA result, 93.9%. The sensitivity of the RSV-EIA compared to direct FA was 91.5% (43/47) with a specificity of 96.5% (83/86). These data represent the preclinical evaluation of the Abbott RSV-EIA. This assay could prove to be a useful alternative to virus isolation or direct FA for the diagnosis of RSV infection.

Antigens, Viral↗

Stress as a precipitating factor in subjects with recurrent herpes labialis.

The model of recurrent herpes labialis was selected to evaluate the role played by stress in increasing susceptibility to illness. Initially, 35 paid volunteers with recurrent herpes were enrolled in the project. Compared with 35 age- and sex-matched controls, this group demonstrated a familial predisposition for recurrent herpes labialis. Eighteen subjects without confounding variables known to precipitate recurrent herpes infections completed a pretested "stress" questionnaire during a dormant and again during an active stage of infection. In the week prior to the appearance of a recurrence, this group experienced increased daily hassles, increased stressful life events, and higher state anxiety. These findings are discussed in the broader context of stress-associated disease with some speculations concerning a possible biologic mechanism, which involves modulations of T-lymphocyte function.

Adult↗