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Biomedical subjects

D M Super

Publications and source records attributed to D M Super.

32 records · Page 2Linked to original sources

Host factors and early therapeutic response in acute otitis media.

To evaluate the relationship between eradication of bacterial infection and clinical improvement in children with otitis media, we reviewed the clinical outcome of bacterial otitis media in patients enrolled in double-blind trials of antibacterial therapy from 1979 to 1988. Cultures of middle ear exudates showed the distribution of bacterial pathogens to be similar to that observed in other geographic areas. Two hundred ninety-three patients had otitis media caused by bacterial pathogens and underwent repeat tympanocentesis after 3 to 6 days of therapy. Bacteriologic success was demonstrated in 253 patients (86%); 40 patients (14%) had bacteriologic failure. Children who had bacteriologic failure were younger than those with bacteriologic success (median age 10.6 vs 18.5 months; p = 0.001); 38% of patients who had bacteriologic failure were black, compared with 18% of patients with bacteriologic success (p = 0.007). Gender, history of frequent otitis media, and presence of bilateral otitis media were not risk factors for bacteriologic failure. Clinical success was demonstrated in 261 patients (89%); 32 patients (11%) had clinical failure. Agreement between clinical and bacteriologic response was 86% (95% confidence interval: 81.6% to 89.6%). Ninety-three percent (236/253) of subjects whose infection was eliminated had clinical resolution, whereas 37% (15/40) of those with bacteriologic failure had persisting symptoms or signs of clinical failure. We conclude that failure to eliminate bacteria from the middle ear is often associated with persistent signs and symptoms. Bacteriologic failure affects children less than 18 months of age almost exclusively. Bacteriologic and clinical failure are frequently discordant; mechanisms unrelated to the bacterial infection may explain some of the persisting clinical signs.

Acute Disease↗

Cefixime compared with amoxicillin for treatment of acute otitis media.

Cefixime was compared with amoxicillin for treatment of acute otitis media in a randomized trial. Results of tympanocentesis on day 3 to 5 of therapy were used as the major outcome. Total daily doses were 8 mg/kg of cefixime and 40 mg/kg of amoxicillin. One hundred twenty-six patients were randomly assigned to receive treatment; 64 cultures grew pathogens. Pathogens were eradicated from the middle ear after 3 to 5 days of therapy in 27 (79.4%) of 34 children given amoxicillin and 26 (86.7%) of 30 children given cefixime (p = 0.47). When Streptococcus pneumoniae cases were analyzed, bacteriologic cure occurred in 14 (93.3%) of 15 children given amoxicillin and 12 (75%) of 16 given cefixime (p = 0.333). When cases of Haemophilus influenzae infection were analyzed, significantly more cures occurred with cefixime (10/10, 100%) than amoxicillin (8/13, 62%) (p = 0.046). Pathogens associated with failure of amoxicillin therapy were H. influenzae (five cases, two beta-lactamase-positive), S. pneumoniae (one case), and Moraxella catarrhalis (one case, beta-lactamase-positive). The four failures with cefixime therapy were all in patients infected with S. pneumoniae. Rates of rash, diarrhea, and vomiting were the same in both groups and did not necessitate stopping therapy. We conclude the following: (1) Cefixime and amoxicillin were equivalent in overall clinical and bacteriologic efficacy for otitis media. (2) Cefixime was more efficacious than amoxicillin in treating H. influenzae otitis media and should be preferred when H. influenzae is the suspected etiologic agent. (3) Side effects of both drugs were mild and equivalent.

Acute Disease↗

Diagnosis of gestational diabetes in early pregnancy.

OBJECTIVE: To determine whether glucose intolerance can be identified early in gestation in a high-risk population so that early intervention can be planned to prevent associated morbidity. RESEARCH DESIGN AND METHODS: After appropriate dietary preparation, patients with a high risk for gestational diabetes underwent a 50-g oral glucose screening test during fasting. Patients were tested on enrollment and every 10 wk until delivery. Those with a 1-h plasma glucose value of greater than or equal to 7.5 mM underwent a 100-g oral glucose tolerance test. Gestational diabetes was based on either a markedly abnormal 50-g screening test or abnormal 100-g oral glucose tolerance test. RESULTS: Ten of 15 (66%) patients who developed gestational diabetes were diagnosed during the first half of the pregnancy. Six were diagnosed in the first trimester. If the definition of an abnormal 1-h plasma glucose value was lowered from 7.5 to 7.2 mM, an additional 2 patients could have been identified in the first trimester with an improvement in sensitivity from 70 to 91% with only a slight drop in specificity (from 91 to 88%). Diagnosis of gestational diabetes was not enhanced by measuring plasma insulin concentrations or insulin-glucose molar ratios. CONCLUSIONS: The diagnosis of gestational diabetes in a high-risk population can be made in the first half of pregnancy. Early diagnosis should permit evaluation of intervention strategies, which may result in improved perinatal outcome.

Adult↗

Rheologic properties of mixed hemoglobin gels: deoxyhemoglobins S and F.

To obtain new information concerning the behaviors--and in turn, the structures--of gels formed from mixtures of S and F hemoglobins, their rheologic properties have been characterized by stress relaxation. The variables manipulated were (1) initial total hemoglobin concentration; (2) mole fraction of hemoglobin S present in the mixture; (3) hemoglobin F as only intact tetramer or as both tetramers and hybridized hemoglobin; (4) hemoglobin F as predominantly G gamma, A gamma, or a mixture of gamma chain types; (5) annealing time; (6) shear history, (7) temperature; and (8) temperature and time of annealing. Characteristics monitored to gain information about the effect of these variables on gel properties were (1) lag time, (2) polymer mass, (3) polymer fraction, (4) polymer composition, (5) equilibrium total hemoglobin activity, and (6) solidity/total or hemoglobin S polymer mass (or total or hemoglobin S fraction). As expected, mixed hemoglobin S and F gels were less solid than pure hemoglobin S gels of similar initial total hemoglobin concentrations because of lower polymer mass, and gel properties were influenced by annealing time, shear history, temperature, and temperature and time of annealing. However, when solidities were compared on the basis of similar quantities of gel present, mixed hemoglobin S and F gels were found to be more solid than those of pure S as the mole fraction of hemoglobin S decreased in the initial mixture. This is explained by the predominant influence on gel properties of high hemoglobin activity incurred by the volume exclusion effect of the total hemoglobin concentration. Pathophysiologic implications of these findings for various sickle cell disorders are proposed.

Anemia, Sickle Cell↗

Rheologic properties of mixed hemoglobin gels: deoxyhemoglobins S and A.

To obtain new information concerning the behaviors, and in turn the structures, of gels formed from mixtures of S and A hemoglobins, their physical properties have been characterized by stress relaxation with a rotational rheometer. The variables manipulated were (1) initial total hemoglobin concentration, (2) mole fraction of hemoglobin S present in the mixture, (3) hemoglobin A as intact tetramer only or as both tetramer and hybridized hemoglobin AS, (4) annealing time, (5) shear history, (6) temperature, and (7) temperature and time of annealing. Characteristics monitored to gain information about the effect of these variables on gel properties were (1) lag time, (2) polymer mass, (3) polymer fraction, (4) polymer composition, (5) equilibrium total hemoglobin activity, and (6) solidity/total or hemoglobin S polymer mass (or total or hemoglobin S fraction). As expected, mixed hemoglobin SA gels were less solid than those of pure S of similar initial hemoglobin concentrations because of lower polymer mass, and gel properties were influenced by shear history, annealing time, temperature, and temperature and time of annealing. However, when solidities were compared on the basis of similar quantities of gel present, mixed hemoglobin SA gels were found to be more solid than those of pure S as the mole fraction of hemoglobin S decreased in the initial mixture. This is explained by the predominant influence on gel properties of high hemoglobin activity incurred by the volume exclusion effect of the total hemoglobin concentration. The presence of hemoglobin A with hemoglobin S results in polymers and gels that differ from those found in pure hemoglobin S. Pathophysiologic implications of these findings for sickle cell disorders are proposed.

Anemia, Sickle Cell↗

Gestational diabetes mellitus: does it recur in subsequent pregnancy?

The recurrence of glucose intolerance was examined in 36 women with an index pregnancy complicated by gestational diabetes who received antepartum care at the same institution because of a subsequent pregnancy. Standard oral or intravenous glucose tolerance tests were used to document glucose intolerance or gestational diabetes. Twenty patients had gestational diabetes in the subsequent pregnancy, whereas one third of the patients tested did not demonstrate an abnormality of carbohydrate metabolism. The patients with consecutive pregnancies complicated by gestational diabetes were heavier and were delivered of heavier neonates than the patients who did not develop gestational diabetes again. Unlike the nondiabetic group, the patients who remained gestationally diabetic weighed significantly more in the subsequent pregnancy than in the index pregnancy. These results indicate that patients with gestational diabetes should be tested in subsequent pregnancies because of the impact of gestational diabetes on birth weight. However, these results also suggest that the glucose tolerance test may not be a reliable test for the detection of abnormal carbohydrate metabolism.

Adult↗

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↗

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↗

An analysis of waiting times in a pediatric emergency department.

Waiting times in a pediatric emergency department were studied using direct observations of patients and health providers on 14 separate days. The mean waiting time (from entry to first physician contact) of the 216 children studied was 49 minutes. Time spent in the waiting room was increased by both the nonavailability of a nurse and the nonavailability of an examining room, and was decreased by the severity of the patient's illness. Time spent in the examination room waiting for the physician was related to the availability of the physician and the number of patients concurrently registered in the emergency department as well as the severity of their complaint. Recommendations for decreasing waiting time, based on the observations, are made. Although each setting is unique, the study provides a model for the analysis of waiting patterns in similar facilities.

Child↗

Relative activation of milk lipoprotein lipase by serum of cows fed varying amounts of fat.

A routine laboratory assay to evaluate relative concentrations of lipoprotein lipase activator (apo C-II) in cow serum was developed. The assay was linear for at least 120 min after an initial, unexplained, lag ime of 13 to 15 min. Half-maximal activation was in the range of 1 to 2% serum in the assay. Inhibition of activation was indicated at high amounts (10%) of serum. Activation from plasma was half that from serum, presumably caused by an increase in substrate Km in the presence of heparin. Use of glyceryl tri[9,10-3H] oleate yielded excessively high blanks; [2-3H] glyceryl triolein is suggested for routine assay. Relative amounts of activator were not different between dry and lactating cows fed "conventional" diets. Activator concentration increased linearly with increasing dietary fat and was related to concentration of total lipid in plasma. The assay may provide a useful adjunct in studies on lipoprotein metabolism.

Animals↗

Weekly telephone contact does not enhance the compliance of home apnea monitoring.

OBJECTIVE: To evaluate the effect of weekly telephone contact with families in enhancing the use of home apnea monitors. STUDY DESIGN: This was a prospective, randomized, single-blinded study of 65 infants who were prescribed home apnea monitoring at the time of initial discharge from the hospital. Exclusion criteria included participation in any other study involving home monitoring or nonavailability of home telephone. Infants were randomized either to the "standard" or "telephone" group by a stratified balanced block technique. All families were instructed to use the monitor during the first 4-week period at all times except during bathing and during the second 4-week period at all unattended times and at night. The families in the telephone group were contacted weekly for 8 weeks. The telephone interview reviewed the events of the previous week but did not include specific encouragement to use the monitor. Both groups received routine pediatric care and follow-up at our high-risk premature clinic. The primary outcome measure was compliance measured as the percentage of time as well as the hours per day that the infant spent on the monitor as recorded by the documented monitor. RESULTS: The telephone (n = 30) and standard (n = 32) groups were similar (p > 0.10) with respect to birth weight (1567 +/- 778 versus 1710 +/- 777 gm), gestational age (30.9 +/- 4.2 versus 31.1 +/- 4.6 weeks), maternal age (24.9 +/- 6.0 versus 25.3 +/- 5.4 years), and commercial insurance (46.7% versus 46.9%), a marker of higher socioeconomic status. Compliance of the telephone versus the standard group was similar during the first 4-week period (74.7 +/- 24.9 versus 75 +/- 27.8%, p = 0.85) (17.9 +/- 5.9 versus 18.2 +/- 6.6 hours/day), the second 4 week period (63.4 +/- 29.1 versus 58.9 +/- 30.9%, p = 0.59) (15.2 +/- 7.0 versus 14.1 +/- 7.4 hours/day) and the entire 8-week period (69.3 +/- 24.7 versus 67.7 +/- 26.2%, p = 0.82, Mann-Whitney U-test) (16.7 +/- 6.0 versus 16.1 +/- 6.5 hours/day), respectively. An abnormal pneumocardiogram at the time of discharge was the only identified factor that improved the compliance for the entire 8-week period (73.1 +/- 22 versus 52.1 +/- 28.5%, p = 0.02) (17.5 +/- 5.2 versus 12.5 +/- 6.8 hours/day) and the first 4-week period of monitoring (81.7 +/- 22.9 versus 59.5 +/- 31.3%, p = 0.01) (19.6 +/- 5.5 versus 14.2 +/- 7.5 hours/day). CONCLUSION: Weekly telephone contact, without specific encouragement to use the monitor, did not improve compliance. Compliance was greater in subjects who had abnormal pneumocardiogram results at the time of discharge from hospital regardless of their telephone/standard group assignment. We speculate that in this already compliant population, more targeted advice is necessary to increase compliance.

Apnea↗

The effect of music-based imagery and musical alternate engagement on the burn debridement process.

Management of pain is a primary concern in the treatment of burn patients. The intent of this study was to test the efficacy of music-based imagery and musical alternate engagement in assisting burn patients in managing their pain and anxiety during debridement. Twenty-five patients, 7 years of age and older, who were admitted to the Comprehensive Burn Care Center were enrolled in the study, which used a repeated-measures design with subjects serving as their own control. Subjects were randomly assigned to 1 of 2 groups. Those placed in Group A received music therapy intervention during their first dressing change, and no music therapy on the following day. Group B received no music therapy intervention during their first dressing change and music therapy during their next dressing, on the following day. Data were collected at 4 intervals in the medical procedure; in the patient's room before transfer to the treatment room, in the treatment room during debridement, in the treatment room after debridement, and upon returning to the patient's room. The measurements taken were pulse, patients' self-report of pain, patients' self-report of anxiety, and the nurse's observation of patients' tension. There was a significant reduction in the self-reporting of pain in those who received music therapy in contrast to those who did not receive music therapy (P < .03). Music therapy is a valuable noninvasive intervention for the treatment of pain after burn injury.

Adolescent↗