Biomedical subjects
Publications and source records attributed to D W Smith.
Two new issues of pet ownership were considered in a mail questionnaire and an interview survey of a large number of elderly people age sixty and over. First, evidence was obtained that pets are an important determinant of housing choice. Second, many elderly pet owners have made no arrangements for the pet if they predecease it or become unable to care for it. Problems related to these issues are discussed.
BACKGROUND: Although the antiviral agent ribavirin improves the course of lower respiratory tract disease in spontaneously breathing infants with respiratory syncytial virus infection, it is not known whether ribavirin can benefit infants with severe respiratory syncytial virus disease who require mechanical ventilation. METHODS: We conducted a randomized, double-blind, placebo-controlled evaluation of ribavirin (20 mg per milliliter) administered continuously in aerosolized form to infants receiving mechanical ventilation for respiratory failure that was caused by documented respiratory syncytial virus infection. RESULTS: Of the 28 infants (mean [+/- SD] age, 1.4 +/- 1.7 months) enrolled, 7 had underlying diseases predisposing them to severe infection (mean age, 3.0 +/- 2.6 months), and 21 were previously normal (mean age, 0.8 +/- 0.9 month). Among the 14 infants who received ribavirin, the mean duration of mechanical ventilation was 4.9 days (as compared with 9.9 days among the 14 who received placebo; P = 0.01), and the mean length of supplemental oxygen use was 8.7 days (as compared with 13.5 days; P = 0.01). The mean length of the hospital stay was 13.3 days after treatment with ribavirin and 15.0 with placebo (P = 0.04). When only the 21 previously normal infants were considered, the mean length of the hospital stay was 9.0 days for the ribavirin recipients and 15.3 days for those who received placebo (P = 0.005). CONCLUSIONS: In infants who require mechanical ventilation because of severe respiratory syncytial virus infection, treatment with aerosolized ribavirin decreases the duration of mechanical ventilation, oxygen treatment, and the hospital stay.
OBJECTIVE: To report a recent fatal case of encephalitis associated with evidence of Murray Valley encephalitis virus infection, only the second fatality from this infection in Western Australia. CLINICAL FEATURES: An 18-month-old Aboriginal boy was admitted to hospital in northwest Western Australia with proven Haemophilus influenzae type b meningitis. INTERVENTION AND OUTCOME: After an initial good response to antibiotics (amoxycillin and cefotaxime) he relapsed and died with evidence of encephalitis. Analysis of serum showed a high titre of antibody to Murray Valley encephalitis (MVE) virus with the presence of specific IgM. No evidence was found for other infective agents. CONCLUSION: It is likely that this child died from MVE which followed his bacterial meningitis. Of the strains of mosquitoes trapped in the area of suspected infection 77.8% were Culex annulirostris, the major vector species for MVE. No MVE virus was isolated from these mosquitoes, but serum from one of the sentinel chickens contained MVE virus antibodies, indicating the presence of the virus in that region.
The purpose of this study was to develop and evaluate a guinea pig model of experimental airborne tuberculosis for its ability to assess chemotherapeutic regimens for their efficacy against virulent tubercle bacilli in vivo during the initial phase of treatment. The tissues examined included primary lung lesions and the metastatic foci in lung and spleen which result from the naturally occurring bacillaemia. The treatments examined, INH + RIF, INH + EMB, EMB + RIF, were initiated 4 weeks after infection and were continued for 8 weeks. Although minor differences were observed in the time of onset of a significant bactericidal effect or in the rate of decline in the microbial population, all three treatment combinations resulted in a significant reduction in the number of M. tuberculosis H37Rv recovered from primary lung lesions, primary lesion-free lung lobes and spleen. X-rays taken of excised inflated lung lobes showed a relationship between the degree of calcification of primary lung lesions and the number of surviving bacilli.
Cochleotopic representation in cortex (AI) is extensively reorganized in cats having neonatal, bilateral high frequency cochlear hearing loss. Anterior areas of AI, normally devoted to high frequencies, contain neurons which are almost all tuned to one lower frequency. This frequency corresponds, at the level of the cochlea, to the border between normal and damaged haircell regions.
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Putative oxidative metabolites of the lead antipsychotic agent tiospirone (1) were synthesized to assist in the identification of the authentic metabolic products found in human urine samples. Thus far, six authentic metabolites have been correlated to the synthetic species. The putative metabolites were further examined in vitro to assess their central nervous system therapeutic potential. SAR analysis of these derivatives indicates that hydroxyl substitution, particularly in the azaspirodecanedione region of the molecule, diminishes the dopamine D-2 affinity of the species without significantly altering the serotonin type-1A and type-2 interactions. In addition, an increase in alpha 1-adrenergic affinity appears to be linked to the attenuation of effects at the dopamine receptors. The biological profile of the 6-hydroxytiospirone metabolite 42 was exemplary in these respects and the in vivo actions of this compound suggest potent antipsychotic potential with a minimal liability for extrapyramidal side effects (EPS). While compound 42 has been unambiguously characterized as an actual human metabolite of tiospirone, the role of 42 in the observed antipsychotic activity of the parent drug, if any, has not yet been determined.
The Health Care Financing Administration (HCFA) uses information from hospital bills, such as age, sex, and diagnoses, to estimate statistical models for the probability, or risk, of death during and after hospital stays. The average risk estimates (expected death rates) are compared with the actual death rates to identify potentially poor quality of care. However, the methods have been criticized as inadequate and an often cited reason is the failure to incorporate risk factors for mortality that are known from clinical research. This hypothesis was tested using a stratified, random sample of 41,963 Medicare patients in 84 hospitals. Many clinical measurements were abstracted for testing as possible risk factors, and a few (26) were identified as useful predictors of death using logistic regression. The estimated regressions accounted for 39% of the variation in mortality, a standard severity classification accounted for 29%, and a relatively simple classification of patients into 17 groups, based on diagnoses, accounted for 17%. The logistic regressions yielded more accurate estimated mortality rates than the severity classification, which in turn was superior to the estimation methods used by HCFA. The HCFA methods were found to be biased in identifying outlier hospitals and this bias can be removed or ameliorated by using clinical risk factors to predict mortality. It is possible to estimate the risk of death more accurately using clinical risk factors and to measure the quality of care.
The possibility of vascular injury should always be kept in mind during lumbar laminectomy. Patients with pre-existing vascular disease are predisposed to injury. Unexplained hypotension is highly suggestive of a vascular catastrophe and is an indication for more detailed examination, sometimes laparotomy. If the patient's clinical condition is stable, consider arteriography. The development of high-output cardiac failure in a patient who has recently undergone lumbar laminectomy is almost diagnostic of traumatic arteriovenous fistula. The best prognosis for recovery of acute vascular interruption occurs with immediate treatment within 24-48 hours. Continued awareness of the possible occurrence of these injuries and familiarity with their various manifestations will facilitate early diagnosis, prompt operative repair, and improved mortality.
Structural features of three analysed bacterial DNA replication origin classes (six enteric origins, three pseudomonad origins, and the Bacillus subtilis origin region) are compared in order to deduce characteristics common to all bacterial origins and characteristics that distinguish the three origin classes. The two Pseudomonas aeruginosa origins are shown to map within 10 kb of each other, and correlations are drawn with four potential origin regions in B. subtilis. The enteric origin class is further distinguished from the other two classes by its genetic organization, the presence of GATC sites, and the role of Dam methylation in enteric initiation. The pseudomonad origin class has the most features that are common to all of these bacterial origins, and hence may be the paradigm bacterial origin class.
This study reports on the evaluation of the second North Carolina Healthful Living Institute (HLI), a statewide conference to promote comprehensive school health education. A comparison of year one and year two evaluation results is included. Based on a theoretical framework derived from the theory of diffusion of innovations within organizations, the impact of the HLI was assessed by studying characteristics of school districts sending representatives to the HLI and the composition of teams from each school district, and using pretest and posttest measures of participants' perceptions of the importance of health as a content area and participants' perceptions of the importance of the various components of comprehensive school health. Results indicate the effect of school health promotion conferences is linked to characteristics of school district teams, with the Institute needing to attract more varied teams, and teams from smaller, rural districts.
Arrow sheath introducers are useful during massive transfusion as well as during catheter insertion. However, each component (sheath, side port, and obturator/catheter) probably progressively impedes maximum flow. This study quantitates these flow changes. Six configurations (C) were tested: (C1) sheath; (C2) sheath, side port; (C3) sheath, side port, obturator; (C4) C3 with 1.5-in obturator; (C5) C3 with 0.25-in obturator; (C6) no components. Flow was measured five times with each configuration and compared. Flows (mL/min) (mean +/- SE) were: (C1) 838.1 +/- 11.2, (C2) 283.4 +/- 9.2, (C3) 149.9 +/- 7.9, (C4) 176.0 +/- 14.0, (C5) 232.5 +/- 5.5, (C6) 1030.5 +/- 11.6. Flow decreased progressively with C2 and C3 (P less than 0.0001). C4 did not increase flow, but C5 did (P less than 0.0001). C5 flow was comparable to C2 but less than C1 (P less than 0.0001). C6 flow was larger than any other configuration (P less than 0.0001). Flow increases in C2 and C5 over C3 and C4 were modest (25%-50%) compared with C1 (250%). Therefore, we do not recommend removing or cutting the obturator to improve flow. During massive transfusion, we recommend removal of the side port until smaller flows suffice.
In this prospective study examination was made of whether (a) time on the operating table, (b) proportion of intraoperative diastolic hypotensive episodes, (c) age, (d) preoperative serum albumin, (e) preoperative total protein levels, and (f) preoperative Braden scores could identify those patients who do and do not develop pressure sores during elective surgery. The stratified sample consisted of 125 adult patients. Fifteen patients (12%) developed a total of 23 pressure sores. A discriminant function using time on the operating table, extracorporeal circulation, and age emerged as the best predictor correctly classifying 12 of 15 patients who developed pressure sores and 83 of 110 patients who remained pressure sore free.
This study assessed the contribution of the apical hair cells to hearing. Guinea pigs, chinchillas and monkeys were behaviorally trained using positive reinforcement to respond to pure-tone stimuli. When a stable audiogram had been determined, each subject received one of three experimental treatments: ototoxic drug administration, low-frequency noise exposure, or the application of a cryoprobe to the bony wall of the cochlear apex. After post-treatment audiograms stabilized, subjects were euthanized and the percentage of hair cells remaining was assessed by light microscopy. Results indicate that a redundancy of encoding mechanisms exist in the mammalian cochlea for low-frequency stimuli. They also suggest that a very small percentage of apical hair cells are sufficient for some low-frequency hearing. Finally, data from this and other studies suggest that the low-frequency threshold shift caused by the loss of a certain percentage of apical hair cells is less pronounced than the high-frequency threshold shift caused by the loss of a comparable percentage of basal hair cells. These data agree with anatomical and electrophysiological evidence that functional as well as anatomical differences may exist between the apex and base of the cochlea.
A test was devised for exploring the question of whether it will be possible to identify genes in large-scale genome studies solely by sequence comparison with current sequence collections. To this end, a facsimile data set was constructed by dividing GenBank Release 56 randomly into two halves, one to serve as a reference set and the other intended to simulate raw data anticipated from large genome sequence projects. All supplementary information and identifying marks were removed from the test set after assignment of random identification numbers to each entry and their encryption. Because noncoding intervening sequences (introns) are underrepresented in GenBank, a program that introduced (simulated) introns into mRNA and prokaryotic sequences was devised. In a further attempt to make the problem of identification more realistic, random base substitutions and single-base deletions were also incorporated. The randomly ordered entries were concatenated, along with random intergenic flanking sequences, into a single long "chromosome" 33 Mb in length and then cut into "cosmids" 50-100 kb long. The chopping process was conducted in such a way that terminal overlaps would allow the order of the entries in the chromosome to be reconstituted. Finally, the sequences of a substantial fraction of the cosmids were converted to their complements. Preliminary searching of 10 test cosmids revealed that more than two-thirds of the entries in the test set should be readily identifiable by type of gene product solely on the basis of comparison with the reference set. These preliminary results suggest that existing computer regimens and sequence collections would be able to identify the majority of eukaryotic genes in any new raw data set, the existence of introns not withstanding. Moreover, the analysis can be conducted in pace with the data collection so that the search results and summary identifications will be instantly available to the research community at large.
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Nicardipine, a new dihydropyridine calcium channel blocking agent, has been shown to be effective in the management of hypertension. The adrenergic response to intravenous nicardipine as measured by changes in plasma catecholamine concentrations in seven patients undergoing treatment of postoperative hypertension is reported. Postoperative hypertension was defined as a systolic blood pressure (SBP) greater than 140 mm Hg. Nicardipine or placebo was administered in doses of 10 mg/h, 12.5 mg/h, and 15.0 mg/h for 5 minutes, 5 minutes, and 15 minutes, respectively, to achieve a therapeutic response defined as a reduction of SBP of 15% or more. Once a therapeutic response occurred, patients entered a maintenance period when the study drug infusion rate was reduced to the equivalent of 3.0 mg/h, and the dose was adjusted by 1.0 to 2.5 mg/h every 15 minutes as needed to maintain blood pressure control. Patients who did not respond to the study drug had their treatment code broken and, if on placebo, received open-label nicardipine. Blood samples were taken for the measurement of plasma norepinephrine (NE) concentrations at baseline prior to nicardipine infusion, at the time of therapeutic response, during maintenance, and after discontinuation of nicardipine. There were no significant differences between the baseline heart rate prior to nicardipine infusion and at the time of therapeutic response, during maintenance, or after discontinuation of the infusion. Mean NE concentrations at baseline prior to nicardipine infusion were 589.3 +/- 140.1 pg/mL (normal range, 75 to 480 pg/mL). Thus, hypertensive patients in the recovery room have a high degree of background sympathetic stimulation. Nicardipine did not further increase plasma NE levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Comparison of the amino acid sequences of eight proteins from the soil amoeba Dictyostelium discoideum to those of their homologs in bacteria, yeast, and other eukaryotes indicates that Dictyostelium diverged from the line leading to mammals at about the same time as the plant/animal divergence. Yeast appear to have diverged considerably earlier. It is argued that previous analyses indicating that D. discoideum diverged before yeast were misleading because of the nature of the small ribosomal subunit rRNA sequences used in these studies. We suggest that amino acid sequences may be more reliable than untranslated nucleic acid sequences for evolutionary comparisons, especially among organisms with significant skewing of their A+T content.