Biomedical subjects

D A White

Publications and source records attributed to D A White.

At least 37 records · Page 2Linked to original sources

PubMed2001

Implementation and pharmacoeconomic analysis of a clinical staff pharmacist practice model.

The implementation and pharmacoeconomic analysis of a clinical staff pharmacist (CSP) practice model are described. Staff pharmacists at a large, tertiary care, academic medical center were selected and trained to perform clinical pharmacy services under the direction of clinical pharmacy specialist mentors. Clinical interventions by these CSP practitioners were evaluated in terms of direct cost savings (the difference in actual acquisition costs between therapies) and cost avoidance (the dollar value of adverse drug events [ADEs] avoided). The CSPs performed a total of 4959 interventions during a 12-month period. The interventions provided direct cost savings of $92,076 and an estimated cost avoidance of $488,436. Comparing cost savings and cost avoidance with the expenses of providing these services indicated a net economic benefit of $392,660. A new model of pharmacy practice that integrates staff pharmacists into existing clinical practice has the potential to minimize the risks, decrease the costs, and improve the outcomes associated with drug therapy.

Cost Savings↗

PubMed2001

Dental attitudes and behaviours in 1998 and implications for the future.

The 1998 Adult Dental Health Survey included face to face interviews with participants to determine their dental attitudes and behaviours. This article considers reported oral hygiene practices, treatment choices, satisfaction with appearance of teeth, attitudes towards wearing dentures and how these have changed since previous surveys. Although overall there has been a steady improvement in dental health attitudes, adults from disadvantaged households are still lagging behind. This has implications for social equity.

Adult↗

PubMed2001

The differential effects of prenatal stress in rats on the acoustic startle reflex under baseline conditions and in response to anxiogenic drugs.

RATIONALE: The prenatal stress syndrome (PS) is characterized by exaggerated behavioral and physiological responses to stressful stimuli and anxiogenic agents. OBJECTIVES: To characterize the behavioral effects of PS on the acoustic startle reflex (ASR) and to determine the possible role of PS-induced alterations in noradrenergic control of ASR by determining the effects of the alpha2-adrenoceptor antagonists, yohimbine, idazoxan, and RS79948-197. METHODS: PS was induced by exposing pregnant dams to a mild stressor of handling and saline injection (0.1 ml, s.c.) from gestational days 14 to 21. Control dams were left undisturbed throughout pregnancy. Using adult male offspring, all ASR studies consisted of either a 30- or 60-min testing period containing 60 or 120 acoustic startle stimuli trials (95 dB, 50 ms noise burst) at a fixed intertrial interval of 30 s after a 5-min acclimation period. For drug studies, a 3-day repeated measures design was implemented. RESULTS: With the exception of the response to the first startle stimulus on the first day of testing, there were no significant differences in baseline ASR between control and PS offspring. Low doses of yohimbine, idazoxan, and RS79948-197 were anxiogenic in the ASR test in both control and PS offspring. PS offspring were less responsive to higher doses of yohimbine (5 mg/kg) and idazoxan (8 mg/kg) but did not differ from control in their responses to any dose of RS79948-197. CONCLUSIONS: Anxiogenic effects of yohimbine, idazoxan, and RS79978-197, likely mediated via alpha2-adrenoceptor blockade, are similar in control and PS rats. Differences between control and PS rats occurred in the response to higher doses of yohimbine and idazoxan. Non-specific effects of these drugs, such as actions at 5HT1A receptors, may cause their behavioral profile to be altered by PS, and to differ from the highly selective RS79948-197.

Adrenergic alpha-Antagonists↗

PubMed2001

Deficits in memory strategy use related to prefrontal dysfunction during early development: evidence from children with phenylketonuria.

The prefrontal cortex has been implicated in the mediation of executive processes that facilitate learning and memory. The authors hypothesized that children with prefrontal dysfunction related to phenylketonuria (PKU) would experience deficits in learning and memory because of impaired strategy use. They evaluated 23 children with PKU and 23 controls by using the California Verbal Learning Test-Children's Version (CVLT-C). General executive abilities were tested using the Stroop Color and Word Test, the Wisconsin Card Sorting Test, and phonemic and category fluency. Children with PKU, especially older children, showed poorer learning across trials and less use of semantic clustering on the CVLT-C but intact retention of previously encoded information. With the exception of phonemic fluency, deficits were not observed in general executive control. Results are discussed within the context of abnormalities in the prefrontal cortex and white matter of the brain.

Adolescent↗

PubMed2001

Fluorogenic PCR-based quantitative detection of a murine pathogen, Helicobacter hepaticus.

Helicobacter hepaticus infection in mice is being used as an animal model for elucidating the pathogenesis of gastrointestinal and biliary diseases in humans. H. hepaticus, which forms a spreading film on selective agar, is not amenable to routine quantitative counts of organisms in tissues using a CFU method. In this study, a fluorogenic PCR-based assay was developed to quantitatively detect H. hepaticus in mouse ceca and feces using the ABI Prism 7700 sequence detection system. A pair of primers and a probe for this assay were generated from the H. hepaticus cdtB gene (encoding subunit B of the H. hepaticus cytolethal distending toxin). Using this assay, the sensitivity for detection of H. hepaticus chromosomal DNA prepared from pure culture was 20 fg, which is equivalent to approximately 14 copies of the H. hepaticus genome based on an estimated genome size of approximately 1.3 Mb determined by pulsed-field gel electrophoresis. H. hepaticus present in feces and cecal samples from H. hepaticus-infected mice was readily quantified. The selected PCR primers and probe did not generate fluorescent signals from eight other helicobacters (H. canis, H. cineadi, H. felis, H. mustelae, H. nemestrinae, H. pullorum, H. pylori, and H. rodentium). A fluorescent signal was detected from 20 ng of H. bilis DNA but with much lower sensitivity (10(6)-fold) than from H. hepaticus DNA. Therefore, this assay can be used with high sensitivity and specificity to quantify H. hepaticus in experimentally infected mouse models as well as in naturally infected mice.

Animals↗

PubMed2001

Inhibitory control across the life span.

Findings from previous research suggest that inhibitory control improves during early childhood and declines during late adulthood. Very few researchers, however, have examined life-span changes in this ability in single studies. Within this life-span context, we investigated 1 type of inhibitory control--the ability to inhibit aprepotent response and generate an incompatible response--in individuals ranging from 6 to 82 years of age. Examination of raw reaction time data revealed a significantly larger inhibitory control effect for children and older adults than for young adults. Using proportional and z score transformations, we demonstrated that a processing speed explanation is sufficient to account for the differences in performance between children and young adults; this explanation, however, did not adequately explain the discrepancy between young and older adults. Taken together, these findings suggest that, above and beyond differences in processing speed, inhibitory control was less efficient in older adults. Our findings are consistent with the assertion that inhibitory control develops quite early and declines at the later end of the developmental spectrum.

Adolescent↗

PubMed2001

Acute opioid pretreatment potentiates naltrexone-induced drinking suppression in water-deprived rats.

Pretreatment with morphine-like agonists potentiates the behavioral effects of opioid antagonists, possibly reflecting a state of acute physical dependence. Several studies have used operant behavior to quantify these effects. However, little research has been done using unconditioned behavior. One objective of this study was to determine whether opioid agonist pretreatment (e.g., morphine, fentanyl, and meperidine) potentiated naltrexone-induced suppression of water consumption following deprivation. Another objective was to determine whether the agonist pretreatment interval was functionally related to efficacy for the manifestation of acute dependence. Finally, we compared temporally the effects of the three agonists. Adult male Sprague-Dawley rats were water deprived for 18, 20, or 22 h and given an injection (s.c.) of an agonist or saline. After 1.75, 3.75, or 5.75 h, animals received a single dose (s.c.) of naltrexone (0.01-30 mg/kg) or saline. Fifteen minutes later, subjects had access to water for 30 min. A time course of antinociception was constructed after agonist administration, using the tail-flick procedure. All three agonists dose dependently potentiated naltrexone-induced drinking suppression, decreasing the ED50 of naltrexone by as much as 150-fold. There was no clear relationship between agonist efficacy and pretreatment interval. Sensitization to naltrexone was seen up to 6 h after agonist administration, occurring in the apparent absence of an antinociceptive effect. These data extend the range of behavioral effects of opioid antagonists potentiated by opioid agonist pretreatment to suppression of drinking and show that such potentiation can occur in the absence of a prototypical agonist effect.

Analgesics, Opioid↗

PubMed2000

Neural correlates of recovery from aphasia after damage to left inferior frontal cortex.

OBJECTIVE: To determine neural correlates of recovery from aphasia after left frontal injury. METHODS: The authors studied the verbal performance of patients with infarcts centered in the left inferior frontal gyrus (IFG), using a battery of attention-demanding lexical tasks that normally activate the left IFG and a simpler reading task that does not normally recruit the left IFG. The authors used positron emission tomography (PET) and functional MRI (fMRI) to record neural activity in the same group of patients during word-stem completion, one of the attention-demanding lexical tasks. To identify potential neural correlates of compensation/recovery, they analyzed the resulting data for the group as a whole (PET, fMRI) and also for each participant (fMRI). RESULTS: Patients with damage to the left IFG were impaired on all attention-demanding lexical tasks, but they completed the word-reading tasks normally. The imaging studies demonstrated a stronger-than-normal response in the right IFG, a region homologous to the damaged left IFG. The level of activation in the right IFG did not correlate with verbal performance, however. In addition, a perilesional response within the damaged left IFG was localized in the two patients who gave the best performance in the word-stem completion task and showed the most complete recovery from aphasia. CONCLUSIONS: Right-IFG activity may represent either the recruitment of a preexisting neural pathway through alternative behavioral strategies or an anomalous response caused by removal of the left IFG. Perilesional activity in the left IFG may represent sparing or restoration of normal function in peri-infarctual tissue that was inactive early on after injury. This activity may be of greater functional significance than right IFG activity because it was associated with more normal verbal performance.

Adult↗

PubMed2000

Interactive effects of dietary cholesterol and different saturated fatty acids on lipoprotein metabolism in the hamster.

The present study examines the interactive effects of three fatty acids: myristic, palmitic and stearic acids, with dietary cholesterol, on lipoprotein metabolism in the hamster. Each saturated fatty acid was fed at a concentration of 100 g pure synthetic triacylglycerol/kg in the presence of 100 g triolein/kg and was fed in the presence of 0.05, 1.2 or 2.4 g dietary cholesterol/kg. Dietary cholesterol increased the concentration of cholesterol in each of the major plasma lipoprotein fractions. The largest effects on VLDL and LDL were seen in the presence of tripalmitin where the increase between the lowest and highest dietary cholesterol groups were 129% and 38% respectively. In contrast, HDL showed the greatest change in the tristearin group when the equivalent increase was 59%. No interactive effects of dietary cholesterol and fat were seen on hepatic mRNA concentrations for the LDL receptor, hydroxymethylglutaryl-CoA reductase or the microsomal triacylglycerol transfer protein. As the amount of cholesterol in the diet increased, large differences were seen in the storage of hepatic cholesterol ester. At the highest dietary cholesterol intake the amount of hepatic cholesterol ester was 1.7-fold higher in the animals fed trimyristin compared with those fed tripalmitin. These results suggest that, as the amount of cholesterol in the diet is increased, palmitic acid becomes more hypercholesterolaemic. This is associated with a reduced ability to store cholesterol ester in the liver.

Analysis of Variance↗

PubMed2000

Exploring the relationship between age, executive abilities, and psychomotor speed.

Age-related declines in executive abilities have been widely reported and are thought to result from neuropathological changes in the prefrontal cortex. Some investigators have suggested that age-related changes in cognition may be the result of slowed information processing speed rather than declines in specific cognitive abilities. We examined the relationships among age, executive abilities, and psychomotor speed in 40 older adults and 46 young adults. Both verbal and nonverbal tasks were administered that measured 2 aspects of executive ability: set formation and set shifting. Executive and psychomotor speed tasks were paired based on similarities in basic task demands. Our results revealed that poorer executive performance was associated with increasing age. Further, although psychomotor speed attenuated the relationship, age accounted for a unique and significant proportion of variance in executive performance after controlling for psychomotor speed. These results suggest that age has an effect on prefrontally mediated executive abilities that cannot be explained solely in terms of psychomotor slowing.

Adolescent↗

PubMed2000

Working memory: a foundation for executive abilities and higher-order cognitive skills.

This paper presents a discussion of working memory and the relationship between working memory and executive abilities. An overview of three prominent models of working memory is provided with experimental support for each. The importance of assessing working memory in individuals with brain damage and related language disorders is discussed, as well as limitations of the currently available assessment tools. Lastly, future directions for the development of both theory and assessment tools are offered.

Brain↗

PubMed2000

Preliminary study of working memory in children with stroke related to sickle cell disease.

The verbal working memory abilities of children with stroke related to sickle cell disease (SCD) (n = 20) were compared to those of control children with SCD who had no history of stroke (n = 11). Memory span for one-, two-, and three-syllable words was assessed. For children with anterior infarcts, overall span was comparable to that of controls, but the typical effect of word length on span was reduced. For children with diffuse infarcts, overall span was reduced in comparison to that of controls, but the typical effect of word length on span was observed. For children with posterior infarcts, overall span was comparable to that of controls and the typical effect of word length on span was observed. These results provide preliminary evidence that patterns of working memory performance may vary across children with infarcts affecting different regions of the brain.

Adolescent↗

PubMed2000

The utility of open lung biopsy in patients with hematologic malignancies.

The yield and impact of open lung biopsies in patients with hematologic malignancies and unexplained pulmonary processes were assessed and analyzed to determine factors that affected the yield. Records of 63 patients with hematologic malignancy, who underwent 67 open lung biopsies for diagnosis of an unknown pulmonary process from 1996 to 1998 at Memorial Sloan-Kettering Cancer Center, were retrospectively reviewed. A specific diagnosis was found in 41 (62%) of the biopsies. Changes in therapy were made in 37 (57%) of patients after biopsy results, but in 69% of those with a specific diagnosis. Survival at 30 and 90 d was increased in those with specific rather than a nonspecific pulmonary diagnosis. The factor most predictive of finding a specific diagnosis was the presence of a focal rather than a diffuse radiographic abnormality (79% versus 36%, p = 0.003). Neutropenic patients or those on mechanical ventilation had a low chance of finding a specific diagnosis. Having received pulmonary toxic chemotherapy in the 6 mo before the biopsy was associated with finding a nonspecific lung injury. Specific pulmonary diagnoses found were inflammatory diseases in 23% of cases, infections in 21%, and malignancy in 18%. Bronchiolitis obliterans with organizing pneumonia (BOOP) was the most common inflammatory disorder and fungi and bacteria were the most frequent infectious pathogens. Complications occurred in 13% of the biopsies, including five patients who required mechanical ventilation post-procedure; one death was associated with the biopsy. The risk was increased in those with less than 50,000 platelets. Complications were similar with video-assisted thoracoscopy (VATS) compared with thoracotomy. We conclude that open lung biopsy in patients with hematologic malignancy has a significant yield and impact on management of patients with hematologic malignancy.

Adolescent↗

PubMed2000

Interhemispheric interaction during childhood: II. Children with early-treated phenylketonuria.

This study examined whether children with early-treated phenylketonuria (ETPKU) exhibited a disruption in communication between the hemispheres as a function of computational complexity (Banich & Belger, 1990; Belger & Banich, 1992, 1998) when compared to neurologically uncompromised children who were matched in age and IQ. This investigation was motivated by findings that phenylketonuria affects myelination of neurons, including those that make up the corpus callosum, the main neural conduit for interhemispheric interaction. Children performed 2 tasks: a less complex physical-identity task and a more complex name-identity task. For both tasks, we compared performance on across-hemisphere trials, which require interhemispheric interaction, and on within-hemisphere trials, in which no hemispheric interaction is required. On the more complex name-identity task, children with ETPKU exhibited less of a benefit from across-hemisphere processing than did neurologically intact children. These results suggest that the interhemispheric interaction required to complete computationally complex tasks is compromised in children with ETPKU. Such an insufficiency may explain some of the attentional deficits observed in this group of children.

Adolescent↗

PubMed2000

Abnormal flow volume loops in patients with intrathoracic Hodgkin's disease.

STUDY OBJECTIVES: To study the incidence of upper airway obstruction, as measured on the flow volume loop (FVL), in patients with bulky mediastinal Hodgkin's disease; to correlate the FVL with CT of the chest; and to follow the changes in the FVL after treatment of the tumor. DESIGN: Retrospective study of pulmonary function tests (PFTs) and chest CTs performed as part of a clinical trial for Hodgkin's disease. SETTING: Memorial Sloan-Kettering Cancer Center, a comprehensive cancer care center. PATIENTS: Twenty-five patients (15 men and 10 women; age range, 20 to 57 years) with bulky mediastinal Hodgkin's disease enrolled in a clinical trial of chemotherapy followed by external beam radiation therapy. MEASUREMENTS AND RESULTS: Fourteen of 25 patients (56%) had an abnormal FVL prior to therapy; after chemotherapy, only 7 of 25 patients (28%) had an abnormal FVL. The abnormal patterns seen were either those typical of fixed obstruction or variable extrathoracic obstruction. No patient had a pattern typical of variable intrathoracic obstruction. On chest CT scan, 16 patients had grade-I tracheal deformity; 6 had grade-II deformity, and 3 had grade-III deformity. All three patients with grade-III deformity had a fixed obstruction pattern, as did three patients with a grade-I pattern. Patients with a fixed pattern on FVL had significant decreases in inspiratory and expiratory flow rates. CONCLUSION: FVL abnormalities suggesting upper airway obstruction occurred in > 50% of patients with bulky mediastinal Hodgkin's disease. A fixed pattern of obstruction was associated with the lower flow rates and severe tracheal distortion on CT; these patients may warrant special attention prior to general anesthesia or invasive procedures. Asymptomatic patients with abnormal FVLs but normal tracheal profiles need not undergo extensive evaluation. No patients showed the expected pattern typical of intrathoracic obstruction, but rather the major effect was on the inspiratory loop. The authors speculate on the mechanism for this unexpected finding.

Adult↗

PubMed2000

The use of a geographical information system in investigating dental services.

OBJECTIVE: To determine the value of a geographical information system (GIS) in investigating the provision of dental care. DESIGN: Information about dental need and provision of dental services was obtained from districts within the West Midlands. A Geographical Information System (Atlas GIS) was used to answer three different questions about dental services provision within the West Midlands. A GIS is an interactive system that allows data to be analysed according to regular or irregular geographical areas. Once the system is established, it is fairly simple and quick to use. However, the financial and training issues mean that it may not be viable for such a system to be available within each health trust or district, but more appropriately as a central facility which can be accessed by several users. CASE STUDIES: The way in which this system was used to answer three different questions about dental service provision within the West Midlands is demonstrated and evaluated. CONCLUSIONS: Use of a GIS presents information in a way that increases its usefulness in the planning of dental services.

Cleft Lip↗

PubMed1999

Preparation of site-specific antibodies to acetylated histones.

Synthetic peptides corresponding to regions within the amino-terminal domains of the core histones H2A, H2B, H3, and H4, in which epsilon-acetyllysine has been substituted for selected lysines, have been used to raise polyclonal antisera in rabbits. Such antisera can be specific not only for individual acetylated histones but also for histone isoforms acetylated at particular lysine residues. In this article, we describe procedures for the preparation, affinity purification, and initial characterization of site-specific antisera to acetylated histones.

Acetylation↗

PubMed1999

Sensitization to Aspergillus species in the congenital neutrophil disorders chronic granulomatous disease and hyper-IgE syndrome.

BACKGROUND: Hyper-IgE syndrome (HIE) and chronic granulomatous disease (CGD) are congenital immunodeficiency diseases with increased susceptibility to bacterial and fungal infections. Both carry significant morbidity and mortality rates because of invasive infections by Aspergillus species. We encountered 2 patients, one with HIE and one with CGD, in whom detection of sensitization to Aspergillus species preceded the diagnosis of immunodeficiency. With high-dose systemic corticosteroids for allergic bronchopulmonary aspergillosis (ABPA), an inflammatory disorder caused by sensitization to Aspergillus species, pulmonary abscesses developed in the patient with HIE, and the patient with CGD succumbed to an overwhelming Aspergillus species-induced pneumonia. OBJECTIVE: We sought to assess the prevalence of sensitization to Aspergillus fumigatus and the presence of diagnostic criteria for ABPA in patients with CGD and HIE. METHODS: We measured A fumigatus-specific serum IgE, IgG, and precipitating antibodies as indicators for A fumigatus sensitization in the sera of 18 patients with neutrophil disorders (7 with HIE and 11 with CGD). Hospital records were reviewed for the presence of other diagnostic criteria for ABPA (asthma, elevated total serum IgE concentration, and radiographic abnormalities). RESULTS: Twelve (67%) of 18 patients were sensitized to A fumigatus, as evidenced by precipitating A fumigatus-specific antibodies. Six (33%) of 18 patients had serologic evidence of ABPA. Five of those 6 patients had radiologic abnormalities consistent with a diagnosis of ABPA. One patient with HIE also had asthma, thus fulfilling minimal essential criteria for concurrent ABPA. CONCLUSIONS: Patients with HIE syndrome and CGD have a high incidence of sensitization to Aspergillus species. A clinical picture indistinguishable from ABPA may coexist or emerge in patients with CGD or HIE and create a major management dilemma because systemic corticosteroids may accelerate tissue damage and invasive fungal infections. It is important to distinguish individuals with congenital neutrophil disorders from uncomplicated classic ABPA.

Adult↗