Culyer reforms will create new opportunities for research.
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Health Care Reform↗
Biomedical subjects
M Lewis
Publications and source records attributed to M Lewis.
Locomotor activity differences between sympatric patas monkeys (Erythrocebus patas) and vervet monkeys (Cercopithecus aethiops): implications for the evolution of long hindlimb length in Homo.
Homo erectus is notable for its taller stature and longer lower limbs relative to earlier hominids, but the selective pressures favoring such long limbs are unclear. Among anthropoid primates, patas monkeys (Erythrocebus patas) and extant hominids share several extreme characteristics involved with foraging and movement, including the relatively longest lower limb proportions, longest daily travel distances and largest home ranges for their body or group size, occupancy of some of the driest habitats, and very efficient thermoregulatory systems. We suggest that patas monkeys are an appropriate behavioral model with which to speculate on the selective pressures that might have operated on H. erectus to increase lower limb length. Here, in a comparison of the locomotor activities of patas monkeys and sympatric, closely related vervet monkeys (Cercopithecus aethiops), we provide evidence for the hypothesis that patas use their long stride more to increase foraging efficiency while walking than to run, either from predators or otherwise.
Animals↗
Effects of regenerator geometry on pulse tube refrigerator performance.
This paper gives results of the cooling performance of a double-inlet pulse tube refrigerator using various regenerators. The same pulse tube was used for all the experiments and measured 4.76 mm in diameter and 46.2 mm in length. A commercial linear compressor with a swept volume of 4 cm3 was used in these experiments. The operating conditions were held constant at a mean pressure of 2.0 MPa and a frequency of 54 Hz. Using finite difference software called REGEN3.1, developed at NIST, and recent experiment results, we optimized a series of regenerators based on dimensions, materials and screen packing. The values used for calculating the thermal conduction through stacked screens by REGEN3.1 were based on recent experimental results from NIST. The regenerator tubes were designed using 316 stainless steel and titanium materials. The regenerator matrices investigated were 400-mesh and 500-mesh stainless steel screen. The valve settings for both orifices were adjusted to minimize the no-load temperature for all regenerators. A cooling capacity curve from 0 to 3 W was also determined. The performance of the pulse tube refrigerator using the different regenerators is discussed. The experimental results from the various regenerators are evaluated and compared with their corresponding numerically calculated coefficient of performance (COP) and regenerator design as determined by REGEN3.1.
Equipment Design↗
Cognitive functioning in 8- to 18-month-old drug-exposed infants.
This study examined the cognitive functioning in 236 infants at 8 and 18 months of age. Thirty-seven infants were heavily exposed to cocaine in-utero, 30 were lightly exposed, and 169 were not exposed to cocaine. Cognitive functioning was evaluated with the Bayley Scales of Infant Development (2nd ed.; N. Bayley, 1993) at both ages. Infant information processing was also assessed with an infant-controlled habituation procedure. Results indicated that (a) infants of cocaine-abusing women had higher neonatal medical and environmental risk scores; (b) at 8 months, exposure groups did not differ in Psychomotor Development Index, Mental Development Index (MDI) scores, or recovery to a novel stimulus; and (c) infants heavily exposed to cocaine or high environmental risk had a decrease in MDI scores from 8 to 18 months. These results were obtained when neonatal medical and environmental risk, as well as polydrug exposure, were controlled.
Child Development↗
The Australian mortality decline: all-cause mortality 1788-1990.
This review describes the Australian decline in all-cause mortality, 1788-1990, and compares this with declines in Europe and North America. The period until the 1870s shows characteristic 'crisis mortality', attributable to epidemics of infectious disease. A decline in overall mortality is evident from 1880. A precipitous fall occurs in infant mortality from 1900, similar to that in European countries. Infant mortality continues downward during this century (except during the 1930s), with periods of accelerated decline during the 1940s (antibiotics) and early 1970s. Maternal mortality remains high until a precipitous fall in 1937 coinciding with the arrival of sulphonamide. Excess mortality due to the 1919 influenza epidemic is evident. Artefactual falls in mortality occur in 1930, and for men during the war of 1939-1945. Stagnation in overall mortality decline during the 1930s and 1945-1970 is evident for adult males, and during 1960-1970 for adult females. A decline in mortality is registered in both sexes from 1970, particularly in middle and older age groups, with narrowing of the sex differential. The mortality decline in Australia is broadly similar to those of the United Kingdom and several European countries, although an Australian advantage during last century and the first part of this century may have been due to less industrialisation, lower population density and better nutrition. Australia shows no war-related interruptions in the mortality decline. Australian mortality patterns from 1970 are also similar to those observed in North America and European countries (including the United Kingdom, but excluding Eastern Europe.
Adolescent↗
The Australian mortality decline: cause-specific mortality 1907-1990.
This review describes the changes in composition of mortality by major attributed cause during the Australian mortality decline this century. The principal categories employed were: infectious diseases, nonrheumatic cardiovascular disease, external causes, cancer, 'other' causes and ill-defined conditions. The data were age-adjusted. Besides registration problems (which also affect all-cause mortality) artefacts due to changes in diagnostic designation and coding are evident. The most obvious trends over the period are the decline in infectious disease mortality (half the decline 1907-1990 occurs before 1949), and the epidemic of circulatory disease mortality which appears to commence around 1930, peaks during the 1950s and 1960s, and declines from 1970 to 1990 (to a rate half that at the peak). Mortality for cancer remains static for females after 1907, but increases steadily for males, reaching a plateau in the mid-1980s (owing to trends in lung cancer); trends in cancers of individual sites are diverse. External cause mortality declines after 1970. The decline in total mortality to 1930 is associated with decline in infection and 'other' causes. Stagnation of mortality decline in 1930-1940 and 1946-1970 for males is a consequence of contemporaneous movements in opposite directions of infection mortality (decrease) and circulatory disease and cancer mortality (increase). In females, declines in infections and 'other' causes of death exceed the increase in circulatory disease mortality until 1960, then stability in all major causes of death to 1970. The overall mortality decline since 1970 is a consequence of a reduction in circulatory disease, 'other' cause, external cause and infection mortality, despite the increase in cancer mortality (for males).
Adolescent↗
Branched-DNA assay for detection of the mecA gene in oxacillin-resistant and oxacillin-sensitive staphylococci.
The identification of methicillin-resistant staphylococcus isolates in the clinical laboratory has typically been performed by using methods that detect phenotypic expression of resistance determinants. However, these methods may be difficult to interpret and some isolates do not express resistance until selective pressure is administered. Assays that detect genetic determinants are not subject to these limitations and have been effective in distinguishing isolates that are capable of expressing the resistance phenotype. In this study, a novel branched-DNA (bDNA) hybridization assay was used to test for the mecA gene in 416 clinical staphylococcal isolates. The results were compared with those obtained by a PCR-based assay and oxacillin disk diffusion. For 155 Staphylococcus aureus and 261 coagulase-negative Staphylococcus isolates, the bDNA assay and PCR results were 100% concordant. Among the S. aureus isolates, 20 were MecA+ and 135 were MecA-. For the coagulase-negative staphylococci, 150 were MecA+ and 111 were MecA-. The results from the genotypic detection methods were compared with those obtained by oxacillin disk diffusion. No discrepancies were detected among the S. aureus isolates; however, 10 coagulase-negative isolates were MecA+ but oxacillin sensitive and 1 isolate was MecA- but oxacillin resistant. Oxacillin resistance was induced in 6 of the 10 MecA+ isolates previously classified as oxacillin sensitive. These results suggest that the bDNA method described here is a sensitive and efficient method for detection of methicillin resistance in staphylococci and that genetic detection methods may be useful for detection of potential methicillin resistance in the clinical laboratory.
DNA Primers↗
Developmental implications of head growth following intracranial hemorrhage.
This study examined the association between head size at birth, discharge, and 1 year and developmental outcome at 1 year in preterm infants, with and without intracranial hemorrhages (ICH) or associated periventricular echodensities (PVE). The data indicated that most sick preterm infants with small heads at discharge achieved appropriate head sizes at 1 year. Analyses of the 1-year mental and motor performances of 125 subjects revealed that for subjects who did not develop ICH, appropriate head sizes at birth and discharge were associated with good developmental outcome, whereas infants with small heads (< two standard deviations below the mean for age) before hospital discharge were more likely to show poorer developmental outcome at 1 year. For subjects with ICH, birth and discharge head circumference were not predictive of 1-year developmental status; however, normal head size at 1 year was associated with better outcome. This was true for children with transient PVE as well. However, persistent periventricular echodensities were associated with both mental and motor deficits at 1 year, regardless of head growth.
Analysis of Variance↗
CT standard protocols are of limited value in assessing actual patient dose.
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Clinical Protocols↗
Impact of clinical pathways and practice guidelines on the management of acute exacerbations of bronchial asthma.
OBJECTIVES: In 1990, it was estimated that approximately 1% of all US health-care costs (approximately $6.2 billion) were spent on asthma-related health expenses. Of this, hospitalization charges alone exceeded $2.6 billion. Practice guidelines and clinical pathways are being developed to standardize the management of acute asthma with the aim of improving care and safely reducing health-care costs. In this report, we evaluate the impact of an asthma pathway developed and instituted at a large community-based teaching hospital. This pathway was evidence based and was developed by a multidisciplinary group. METHODS: The study was conducted during a 6-month period in 1995, while a similar period in 1994 was used as a historical control period. Data collected included patient demographics, hospital admission and discharge peak expiratory flow rates, pulse oximetry measurements, length of stay, conversion from hand-held nebulizer to metered-dose inhaler, use of corticosteroids within 24 h of hospitalization, and conversion of i.v. steroids to oral steroids. RESULTS: A total of 42 patients were enrolled during the study period. Of these, 19 were placed on the pathway, while 23 were not treated according to the pathway. There were 38 patients in the 1994 historical control period. For 1995, there was no significant difference between the pathway and nonpathway groups with regard to the length of stay (4.4+/-3.3 vs 3.2+/-2.3 days; p > 0.05), hospital discharge peak expiratory flow rates (324 vs 286 L/min; p > 0.05), or use of steroids (100% vs 91%; p > 0.05). However, a significant increase in conversion from hand-held nebulizer to metered-dose inhaler was noted in the pathway group (68% vs 34%; p < 0.05). The data from 1994 compared to 1995 pathway were similar in that there was no difference in the length of stay (3.4+/-2.1 vs 4.4+/-3.3 days; p > 0.05) and/or use of steroids (92% vs 100%; p > 0.05), while a significant increase in hand-held nebulizer to metered-dose inhaler conversion was observed for the 1995 pathway group (68% vs 26%; p=0.002). CONCLUSIONS: We conclude that although the asthma pathway did not significantly reduce length of stay, it was associated with a significant increase in hand-held nebulizer to metered-dose inhaler conversion, resulting in a substantial cost savings of $288,000/year.
Acute Disease↗
Feed intake relative to stage of lactation for dairy cows consuming total mixed diets with a high or low ratio of concentrate to forage.
This experiment examined the effect of feed quality on the relationship between intake and stage of lactation in dairy cows. Two total mixed diets composed of grass silage and concentrate were formulated. The high concentrate total mixed diet was designed to meet energy requirements, and the low concentrate total mixed diet was designed to limit intake. Twenty-four Holstein-Friesian cows were offered the total mixed diets in a full 2 x 2 change-over design with control treatments. The changeover was at 153 d in milk (DIM). For the statistical analyses, two periods of 13 wk, one period before and one period after the changeover, were used. Dry matter intake (DMI), milk yield, body weight, and body condition score were significantly greater for cows fed the high concentrate total mixed diet than for cows fed the low concentrate total mixed diet. Significant interactions between total mixed diet and period were observed for DMI and milk yield. However, no significant residual effects of changing from one total mixed diet to the other were observed. The interactions were due to substantially different slopes of DMI and milk yield relative to DIM for cows fed the two different total mixed diets. For cows fed the low concentrate total mixed diet, there was no effect of stage of lactation on DMI; the slope was 0. For cows fed the high concentrate total mixed diet, there was a significant decline in DMI as lactation progressed.
Animal Feed↗
Diet choice by dairy cows. 2. Selection for metabolizable protein or for ruminally degradable protein?
Diet choice, expressed as grams of high protein feed selected per kilogram of intake, was measured for lactating cows with ad libitum access to two feeds. First, cows were given a choice between a low protein feed and a high protein feed for 9 wk while feeds were alternated between feeders. The proportion of feed chosen from a feeder depended on the feed it contained, which showed that cows selected for feed characteristics. Diet choice was then measured over six periods during which cows had access to either a low protein feed and a high protein feed or to these feeds plus added urea. Diet choice was lower when urea was added, suggesting a substantial effect of the content of ruminally degradable protein (RDP) in feeds on diet selection. All feeds had equal RDP contents in Experiment 3 when early and late lactating cows had access first to two feeds with a low and high yield of metabolizable protein and then to two feeds with a low and medium yield of metabolizable protein. Diet choice did not differ from what was considered to be random and was not affected by milk yield or stage of lactation. No evidence suggests that cows selected for metabolizable protein when both feeds contained adequate RDP.
Animal Feed↗
Immunoglobulin and IgG subclass levels in the African American and Hispanic populations of east Harlem.
BACKGROUND: The normal levels of immunoglobulin and IgG subclasses in African American and Hispanic populations are uncertain. To determine immunoglobulin and IgG subclass levels in this community, we measured serum IgG, IgM, and IgA levels along with IgG subclasses in 303 African American and Hispanic patients in a general medical clinic and an allergy/asthma clinic in East Harlem in New York City. METHODS: Prospective measurement of immunoglobulins and IgG subclasses in a general medical clinic and an allergy/asthma clinic in East Harlem. RESULTS: Ten (3.4%) patients had IgG levels below the lower limit of normal values, two (0.07%) patients had IgA levels below the lower limit of normal values, and two (0.07%) patients had an IgM level below the lower limit of normal values. Twenty-four (8.1%) patients had IgG subclass levels below the lower limit of normal values; 1 patient had low levels of IgG1 and IgG3, 5 patients had low levels of IgG2, and 18 patients had low levels of IgG3. Because low IgG subclasses and allergy/asthma appeared to be associated, we compared IgG subclass levels of the patients with and without allergy/asthma. The mean IgG2 level in the patients without allergy/asthma was 425.1 +/- 199.1 mg/dL (p = 0.05) compared with 345.5 +/- 133.1 mg/dL in the allergy/asthma group, the mean IgG3 level in the patients without allergy/asthma was 85.0 +/- 57.1 mg/dL compared with 64 +/- 34.1 mg/dL in the allergy/asthma group (p = 0.016) but there were no differences in IgG1 and IgG4 levels between the two groups. CONCLUSION: Altogether, our data indicate that humoral immunoglobulin and IgG subclass levels below the lowest normal values occur in the low socioeconomic African American and Hispanic populations, especially in patients with asthma in East Harlem.
Adult↗
Arousal modulation in cocaine-exposed infants.
The ability to modulate arousal is a critical skill with wide-ranging implications for development. In this study, the authors examined arousal regulation as a function of levels of prenatal cocaine exposure in 107 infants at 4 months of age using a "still-face" procedure. Facial expressions were coded. A greater percentage of heavily cocaine-exposed infants, compared with those who were unexposed to cocaine, showed less enjoyment during en face play with their mothers and continued to show negative expressions during the resumption of play following a period when the interaction was interrupted. This finding was independent of other substance exposure, neonatal medical condition, environmental risk, maternal contingent responsivity, and concurrent maternal sensitivity and vocalizations.
Adaptation, Psychological↗
Prospective randomized controlled trial comparing Lichtenstein with modified Bassini repair of inguinal hernia.
We present a prospective randomized study of 80 patients with inguinal hernia who underwent either a modified Bassini repair (n = 38) or a Lichtenstein mesh repair (n = 42). Treatment groups were matched for age, side of hernia, type of hernia and ASA grade. There was no difference in the time taken to perform the two operations: the mean time taken to perform Lichtenstein repair was 26.8 min (range 12 to 49), Bassini repair taking a mean of 27.5 min (range 9 to 51), P = 0.76. There was, however, a difference between the operating times with respect to the type of hernia present, direct hernias being the fastest to repair. Pain scores were assessed by a visual analogue scale, and there was significantly less pain in the Lichtenstein group, P = 0.028. Despite this, there was no difference between the analgesic requirements of the two groups, P = 0.073. In order to assess rehabilitation, lengths of time not working and not driving were assessed. There was no difference in either measurement, P = 0.335 and 0.467 respectively. Patients were followed up a mean of 7 weeks post-operatively (range 1 to 13 weeks). There was no significant difference between the two procedures with regard to post-operative urinary complications, wound infection or other complications. All measurements except the time taken to perform the operation were independent of the surgeon involved. The accuracy of the clinical diagnosis was also assessed, and found to be moderate, with 63% of diagnoses being correct.
Adolescent↗
Who audits the auditors?
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Documentation↗
Acute respiratory distress syndrome. Patient position and motion strategies.
A review of the literature since 1974 indicates that, although there is no consensus as to the mechanism, positioning strategies in patients with ARDS improve PaO2 and may diminish lung parenchymal damage. The effect of these maneuvers on patient outcomes is uncertain. There is no uniform algorithm for the application of these techniques; however, there is sufficient evidence cited in the referenced articles to support the use and early application of the techniques to improve oxygenation.
Animals↗
Comparative anatomy of the aldo-keto reductase superfamily.
The aldo-keto reductases metabolize a wide range of substrates and are potential drug targets. This protein superfamily includes aldose reductases, aldehyde reductases, hydroxysteroid dehydrogenases and dihydrodiol dehydrogenases. By combining multiple sequence alignments with known three-dimensional structures and the results of site-directed mutagenesis studies, we have developed a structure/function analysis of this superfamily. Our studies suggest that the (alpha/beta)8-barrel fold provides a common scaffold for an NAD(P)(H)-dependent catalytic activity, with substrate specificity determined by variation of loops on the C-terminal side of the barrel. All the aldo-keto reductases are dependent on nicotinamide cofactors for catalysis and retain a similar cofactor binding site, even among proteins with less than 30% amino acid sequence identity. Likewise, the aldo-keto reductase active site is highly conserved. However, our alignments indicate that variation ofa single residue in the active site may alter the reaction mechanism from carbonyl oxidoreduction to carbon-carbon double-bond reduction, as in the 3-oxo-5beta-steroid 4-dehydrogenases (Delta4-3-ketosteroid 5beta-reductases) of the superfamily. Comparison of the proposed substrate binding pocket suggests residues 54 and 118, near the active site, as possible discriminators between sugar and steroid substrates. In addition, sequence alignment and subsequent homology modelling of mouse liver 17beta-hydroxysteroid dehydrogenase and rat ovary 20alpha-hydroxysteroid dehydrogenase indicate that three loops on the C-terminal side of the barrel play potential roles in determining the positional and stereo-specificity of the hydroxysteroid dehydrogenases. Finally, we propose that the aldo-keto reductase superfamily may represent an example of divergent evolution from an ancestral multifunctional oxidoreductase and an example of convergent evolution to the same active-site constellation as the short-chain dehydrogenase/reductase superfamily.
Alcohol Oxidoreductases↗