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Biomedical subjects

T Cooper

Publications and source records attributed to T Cooper.

At least 19 recordsLinked to original sources
PubMed2006

Major degradation product identified in several pharmaceutical formulations against the common cold.

Different pharmaceutical preparations against the common cold contain acetaminophen, phenylephrine hydrochloride, and chlorpheniramine maleate. A degradation product had been discovered in these preparations after short- and long-term stability studies. This degradation product was isolated and found to be an adduct of phenylephrine and maleic acid. An account of the isolation and characterization of this compound was published. Our interest in this area led us to synthesize the compound, and we found that the synthesized compound does not have the same spectroscopic properties described in the original paper. Our subsequent work identified the structure of the degradation product as a "Michael addition" product of phenylephrine and maleic acid.

Acetaminophen↗
PubMed2006

Community-onset methicillin-resistant Staphylococcus aureus in an urban HIV clinic.

OBJECTIVES: To determine the proportion of skin/soft tissue infections (SSTIs) and to determine risks for MRSA infection caused by methicillin-resistant Staphylococcus aureus (MRSA) in HIV-infected out-patients. METHODS: We conducted a prospective study of SSTIs in HIV-infected out-patients. A questionnaire was used to record MRSA risk factors and treatment. In vitro testing for antibiotic susceptibility, inducible clindamycin resistance, panton-valentine leucocidin (PVL) toxin, and the staphylococcal chromosomal cassette mec (SCCmec) type was performed using standardized methods. Treatment outcomes included resolution of primary site of infection, nonresolution of infection and reinfection and were confirmed at clinic visit and/or telephone follow-up. RESULTS: Forty-one of 44 patients had an SSTI caused by MRSA. African-Americans comprised 21 of 41 MRSA patients. The median CD4 count of MRSA patients was 411 cells/microL. Four patients required hospitalization and three patients had secondary bacteraemia. Twenty-one of 41 MRSA patients had healthcare-associated (HCA) MRSA risk factors including a history of prior MRSA infection (n=9) and hospitalization within 6 months (n=11). Other prevalent MRSA risk factors included receipt of systemic antibiotics within 6 months (n=21) and previous incarceration (n=19). Twenty-two patients had a significant non-HIV-related comorbid illness. The majority of isolates were susceptible to trimethoprim-sulfamethoxazole, tetracycline, and clindamycin. Inducible clindamycin resistance was detected in 0 of 16 erythromycin-resistant, clindamycin-susceptible MRSA isolates. Twenty-one of 24 isolates tested positive for SCCmec type IV. Twenty-four of 24 isolates tested positive for the PVL gene. Antibiotic treatment was discordant (bacteria nonsusceptible to antibiotic used) in eight MRSA patients. The primary SSTI resolved in 37 of 40 MRSA patients. Recurrence of infection at a site other than the primary site was relatively common (11 patients). CONCLUSIONS: We found a high rate of MRSA causing SSTI in community-dwelling patients. The majority of isolates were positive for PVL and SCCmec IV, which is typical of community-associated MRSA isolates causing SSTIs in the general population. Inducible clindamycin resistance was not detected. Most patients had MRSA risk factors. The initial site of infection resolved in most cases but subsequent MRSA infection was relatively common.

Ambulatory Care Facilities↗
PubMed2005

Separating individual skin conductance responses in a short interstimulus-interval paradigm.

We describe a new method for measuring skin conductance responses, designed to overcome the problem of overlapping skin conductance responses. The method relies on the assumptions that the underlying sudomotor nerve signal has a shorter time-constant than the skin conductance signal itself, and that the sudomotor bursts arrive as discrete, separated events. By converting the skin conductance signal into a time-series with a shorter time-constant, we are able to extract the separated peaks in the estimated underlying driver signal. The separated driver peaks are then used to re-estimate each individual skin conductance response. The method is automated and applied to a normative database of 735 subjects, for which skin conductance was measured during an auditory oddball paradigm.

Acoustic Stimulation↗
PubMed2004

Nicotine-induced changes in neurotransmitter levels in brain areas associated with cognitive function.

Nicotine, one of the most widespread drugs of abuse, has long been shown to impact areas of the brain involved in addiction and reward. Recent research, however, has begun to explore the positive effects that nicotine may have on learning and memory. The mechanisms by which nicotine interacts with areas of cognitive function are relatively unknown. Therefore, this paper is part of an ongoing study to evaluate regional effects of nicotine enhancement of cognitive function. Nicotine-induced changes in the levels of three neurotransmitters, dopamine (DA), serotonin (5-HT), norepinepherine (NE), their metabolites, homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), and their precursor, L-DOPA, were evaluated in the ventral and dorsal hippocampus (VH and DH), prefrontal and medial temporal cortex (PFC and MTC), and the ventral tegmental area (VTA) using in vivo microdialysis in awake, freely moving, male Sprague-Dawley rats. The animals were treated with acute nicotine (0.5 mg/kg, s.c.) halfway through the 300-min experimental period. The reuptake blockers, desipramine (100 microM) and fluoxetine (30 microM), were given to increase the levels of NE and 5-HT so that they could be detected. Overall, a nicotine-induced DA increase was found in some areas, and this increase was potentiated by desipramine and fluoxetine. The two DA metabolites, HVA and DOPAC, increased in all the areas throughout the experiments, both with and without the inhibitors, indicating a rapid metabolism of the released DA. The increase in these metabolites was greater than the increase in DA. 5-HT was increased in the DH, MTC, and VTA in the presence of fluoxetine; its metabolite, 5-HIAA, was increased in the presence and absence of fluoxetine. Except in the VTA, NE levels increased to a similar extent with desipramine and fluoxetine. Overall, nicotine appeared to increase the release and turnover of these three neurotransmitters, which was indicated by significant increases in their metabolites. Furthermore, DA, and especially HVA and DOPAC, increased for the 150 min following nicotine administration; 5-HT and NE changes were shorter in duration. As gas chromatography experiments showed that nicotine levels in the brain decreased by 75% after 150 min, this may indicate that DA is more susceptible to lower levels of nicotine than 5-HT or NE. In conclusion, acute nicotine administration caused alterations in the levels of DA, 5-HT, and NE, and in the metabolism of DA and 5-HT, in brain areas that are involved in cognitive processes.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2003

A multistate outbreak of Salmonella enterica Serotype Newport infection linked to mango consumption: impact of water-dip disinfestation technology.

Fresh produce increasingly is recognized as an important source of salmonellosis in the United States. In December 1999, the Centers for Disease Control and Prevention detected a nationwide increase in Salmonella serotype Newport (SN) infections that had occurred during the previous month. SN isolates recovered from patients in this cluster had indistinguishable pulsed-field gel electrophoresis (PFGE) patterns (which identified the outbreak strain), suggesting a common source. Seventy-eight patients from 13 states were infected with the outbreak strain. Fifteen patients were hospitalized; 2 died. Among 28 patients enrolled in the matched case-control study, 14 (50%) reported they ate mangoes in the 5 days before illness onset, compared with 4 (10%) of the control subjects during the same period (matched odds ratio, 21.6; 95% confidence interval, 3.53- infinity; P=.0001). Traceback of the implicated mangoes led to a single Brazilian farm, where we identified hot water treatment as a possible point of contamination; this is a relatively new process to prevent importation of an agricultural pest, the Mediterranean fruit fly. This is the first reported outbreak of salmonellosis implicating mangoes. PFGE was critical to the timely recognition of this nationwide outbreak. This outbreak highlights the potential global health impact of foodborne diseases and newly implemented food processes.

Adolescent↗
PubMed2001

Lobster sniffing: antennule design and hydrodynamic filtering of information in an odor plume.

The first step in processing olfactory information, before neural filtering, is the physical capture of odor molecules from the surrounding fluid. Many animals capture odors from turbulent water currents or wind using antennae that bear chemosensory hairs. We used planar laser-induced fluorescence to reveal how lobster olfactory antennules hydrodynamically alter the spatiotemporal patterns of concentration in turbulent odor plumes. As antennules flick, water penetrates their chemosensory hair array during the fast downstroke, carrying fine-scale patterns of concentration into the receptor area. This spatial pattern, blurred by flow along the antennule during the downstroke, is retained during the slower return stroke and is not shed until the next flick.

Animals↗
PubMed2001

Differences in nicotine-induced dopamine release and nicotine pharmacokinetics between Lewis and Fischer 344 rats.

Studies have shown a greater preference for the self-administration of drugs such as nicotine and cocaine in the Lewis rat strain than in the Fischer 344 strain. We examined some factors that could contribute to such a difference. The baseline level of extracellular dopamine in nucleus accumbens shell was about 3-times higher in Fischer rats than in Lewis rats (3.18 +/- 0.26 vs. 1.09 +/- 0.14 pg/ sample). Nicotine (50-100 microg/kg)-induced release of dopamine, expressed in absolute terms, was similar in the two strains. Dopamine release expressed in relative terms (as percent of baseline), however, was significantly greater in Lewis rats than in Fischer rats at 30 min after the first nicotine injection. We suggest that the relative increase is of more influence than the absolute level for determining preference; a lower physiological extracellular dopamine level thus represent a risk factor for increased preference. Amphetamine-induced dopamine release expressed in relative terms was not greater in the Lewis strain. In the initial time period of the microdialysis experiments, a sharper peak in nicotine-induced accumbal dopamine release in Lewis and a less but more sustained release in Fischer rats was observed. This release pattern paralleled the faster clearance of nicotine from blood of Lewis compared to Fischer rats. In tissue slices the electrically induced dopamine release was highest in the nucleus accumbens and lowest in the ventral tegmentum. A significant effect of nicotine was lowering the electrically induced release of dopamine in frontal cortex slices from Fischer brain and increasing this dopamine release in the ventral tegmentum of Lewis brain slices indicating that the ventral tegmentum, an area controlling dopamine release in the accumbens, is more responsive to nicotine in the Lewis rat. Nicotine levels tended to be more sustained in Fischer rats in different brain regions, although the difference in nicotine levels between the strains was not significant at any time period. Several factors contribute to nicotine preference, including the endogenous dopamine level, and the sensitivity of ventral tegmentum neurons to nicotine-induced dopamine release. Strain differences in pharmacokinetics of nicotine may also play a role.

Animals↗
PubMed2001

Hais cuaj txub kaum txub--to speak of all things: a Hmong cross-cultural case study.

Cross-cultural medicine is a field that describes how disparate value and belief systems concerning health and disease affect the delivery of health care. This report describes the conflict between a Hmong immigrant family and the Western medical establishment over the care of their child with end stage renal disease [ESRD]. The health care providers, social service agencies and medical center failed to adequately respond to the needs of the family. The medical staff [nephrologist, nurse coordinator, dietician, social worker, and CPS worker] worked with a transcultural nurse, Hmong community health worker and the family, to design and negotiate a treatment plan that would be acceptable to the family and the health care team. Trust was reestablished between the family and the healthcare providers and the medical outcome for the child improved.

Journal Article↗
PubMed2000

Clinical associations and characterisation of antineutrophil cytoplasmic antibodies directed against bactericidal/permeability-increasing protein and azurocidin.

Bactericidal/permeability-increasing protein (BPI) and azurocidin (AZ) are recently described target antigens of antineutrophil cytoplasmic antibodies (ANCA). In this study, BPI-ANCA were demonstrated most often in patients with ulcerative colitis (36/92, 39%), Crohn's disease (17/66, 26%) and cystic fibrosis (11/14, 79%), but also in patients with rheumatoid arthritis (8/40, 20%), systemic lupus erythematosus (SLE) (111/65, 17%) and mixed connective tissue disease (4/18, 22%). BPI-ANCA were also common in sera containing antinuclear (ANA) (9/43, 21%) or antidouble-stranded (ds) DNA (7/28, 25%) antibodies. There was no increased frequency of abnormal alpha1-antitrypsin (alphal1AT) phenotypes in patients with BPI-ANCA, and BPI-ANCA were not more common in individuals with an abnormal phenotype. The predominant IgG subclasses were IgG1 and IgG3; IgA but not IgM was present. Both IgG and IgA BPI-ANCA were high affinity antibodies, and the affinity of IgG antibodies did not change with time in the sera tested. Four of the five sera (80%) containing BPI-ANCA did not bind to denatured, reduced BPI, suggesting that most BPI-ANCA recognised conformational epitopes. AZ-ANCA were demonstrated in 2/11 patients (18%) with Wegener's granulomatosis, 3/12 (25%) with cystic fibrosis and 3/14 (21%) with chronic active hepatitis. AZ-ANCA were present in 5/25 sera (25%) with ANA, but the levels were only marginally elevated. AZ-ANCA were uncommon in patients with inflammatory bowel and rheumatological diseases, and in sera containing other autoantibodies. Again, there was no association with abnormal alpha1-AT phenotypes. BPI represents a major ANCA target antigen in patients with rheumatological as well as inflammatory bowel disease and cystic fibrosis, but AZ-ANCA are uncommon.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2000

A waterborne outbreak of Salmonella Saintpaul.

Contamination of a tank water supply system led to an outbreak of Salmonella Saintpaul with 28 cases of gastroenteritis amongst over 200 workers at a large construction site. The outbreak was identified following notification of two salmonellosis cases by general practitioners from different towns during March 1999. The source of infection, contaminated drinking water, was identified through environmental sampling and confirmed by epidemiological investigations. Frogs and/or mice may have been the original source of the contamination. This report details control measures, the results of investigations and recommendations for future research.

Animals↗
PubMed2000

Heuristic comparison of sertraline with nortriptyline for the treatment of depression in frail elderly patients.

Studies have demonstrated that the selective serotonin reuptake inhibitor antidepressants have similar efficacy to other agents, such as tricyclic antidepressants. However, data are limited for direct comparisons with other antidepressants. The authors conducted a contemporaneous comparison of nursing home residents treated with open-label sertraline in doses up to 100 mg/day with nursing home residents treated in a double-blind randomized study of low vs. regular doses of nortriptyline. There were 97 patients enrolled in the study (28 treated with sertraline), with an average treatment duration of 55 days. There were no differences in the tolerability of sertraline vs. nortriptyline. However, in this group of frail older adults, sertraline was not as effective as nortriptyline for the treatment of depression.

Aged↗
PubMed1999

Family caregiving to elderly African Americans: caregiver types and structures.

OBJECTIVES: This study identified different types of caregivers who provide care to older African Americans, the types of caregiving structures created to provide care, and the factors that help predict caregiving structures. METHODS: A community sample of 330 caregivers caring for 202 elderly African Americans was used. Multinomial logistic regression predicted what type of caregiving structure was created by families to provide care to older relatives. RESULTS: Three types of caregivers were identified: 187 primary caregivers, who were connected to 79 secondary caregivers and 49 tertiary caregivers. Fifteen tertiary-only caregivers who were not connected to other caregivers were identified. Five caregiving structures were found: (i) primary, secondary, and tertiary, (ii) primary and secondary, (iii) primary and tertiary, (iv) primary only, and (v) tertiary-only. Characteristics of care recipients were predictive of caregiving structures. DISCUSSION: Different types of caregivers with distinct roles and responsibilities provided care within defined caregiving structures to older African American family members. Caregiving structures may be individualistic (only one caregiver) or collectivist (two or more caregivers). Caregiving structure is predicted by the care recipients' conditions and situations, but not those of the primary caregiver.

Adult↗
PubMed1998

Contribution of long-bone radiographs to the management of congenital syphilis in the newborn infant.

OBJECTIVE: To determine the contribution of long-bone radiographs to the diagnosis and management of newborn infants at risk for congenital syphilis. DESIGN: Historical cohort. SETTING: Three large hospitals in Houston, Tex. PATIENTS: Eight hundred fifty-three live born infants who were evaluated for the presence of congenital syphilis. INTERVENTION: Long-bone radiographs done as part of the diagnostic evaluation for the presence of congenital syphilis. MAIN OUTCOME MEASURE: Changes in diagnostic classification or management decisions that were based on radiographic findings in the long bones. RESULTS: For 450 infants, radiographic results did not affect management because clinical or historical factors were present that dictated treatment: 26 infants had clinical symptoms of congenital syphilis (65% [17] had abnormalities on radiographs); and 424 infants were born to mothers who were untreated or reinfected (5.9% [25] had abnormalities on radiographs). All of these infants required a full course of therapy regardless of radiologic findings. Born to mothers with possibly inadequate therapy (according to 1993 Centers for Disease Control and Prevention guidelines), 237 asymptomatic newborn infants were candidates for a single injection of penicillin G benzathine if the results of their evaluations were normal; of these, 2 (0.8%) had abnormal radiographic findings. Of the 166 infants born to adequately treated mothers with appropriately falling serologic titer levels, 1 (0.6%) had abnormal radiographic findings (P=.99 between groups). The results of the long-bone radiographs did not alter management for any of the 853 infants who were evaluated for congenital syphilis. CONCLUSIONS: Long-bone radiographic findings, often abnormal in symptomatic infants, do not differentiate between active infection and past infection. The use of long-bone radiographs should be reconsidered in the routine evaluation of infants for congenital syphilis.

Bone and Bones↗
PubMed1998

Glutamate modulation of dopamine measured in vivo with positron emission tomography (PET) and 11C-raclopride in normal human subjects.

Subanesthetic doses of the noncompetitive N-methyl-D-aspartate (NMDA) antagonist ketamine exacerbate psychosis in schizophrenic patients, and ketamine has significant abuse liability. These observations indicate that a secondary effect of ketamine may be to increase dopamine concentrations. The present study was undertaken using positron emission tomography (PET) and the dopamine (D2) radiotracer 11C-raclopride to determine whether ketamine would decrease D2 receptor availability, indicative of an increase in dopamine concentrations. Two scans were performed in seven male control subjects before and after administration of ketamine (0.5 mg/kg, i.v. infused over 20 min). Ketamine significantly increased cortisol levels and decreased dopamine receptor availability in the striatum (specific binding), but not in the cerebellum (nonspecific binding). In addition, the cerebellar binding subtracted from the striatal binding (to account for changes in nonspecific binding) was significantly decreased after ketamine administration. These results provide in vivo evidence for the ability of ketamine to increase striatal dopamine concentrations, consistent with the role of the NMDA receptor in modulating dopamine function.

Adult↗
PubMed1998

An examination of next-day hangover effects after a 100 mg/100 ml dose of alcohol in heavy social drinkers.

AIMS: Carry-over effects or the hangover hypothesis postulates that alcohol continues to impair performance the morning after drinking, even after low or moderate doses. Performance deficits have been attributed to the residual effects of recent drinking. The present study examined evidence for residual alcohol consumption on human performance when blood alcohol level has declined to zero. DESIGN: A within-subjects, repeated measures, placebo controlled experiment was conducted with double-blind alcohol administration to investigate the effects of alcohol the morning after ingestion. SETTING: All subjects were studied in Glasgow, Scotland, UK. PARTICIPANTS: Forty healthy male moderate to heavy social drinkers between 18 and 45 years of age. MEASUREMENTS: Psychomotor performance, subjective state and quality of sleep were examined under alcohol and placebo with a 1-week interval between test sessions. Enough alcohol was given to place subjects above the legal limit for driving at peak blood alcohol. FINDINGS: There was no evidence for impaired performance the morning after ingestion. Effects were found for subjective state and sleep quality. CONCLUSIONS: The findings suggest that after a 100 mg/100 ml dose of alcohol people who: (a) have no alcohol left in their blood and; (b) do not feel hung over will generally be fit to drive.

Adolescent↗
PubMed1998

Potential economic benefits of lower-extremity amputation prevention strategies in diabetes.

OBJECTIVE: To estimate the potential economic benefits of selected strategies from published literature--educational interventions, multidisciplinary clinics, and insurance coverage for therapeutic shoes--to reduce the incidence of lower-extremity amputation among individuals with diabetes. RESEARCH DESIGN AND METHODS: We developed a model to estimate the expected incidence and associated costs of lower-extremity amputation in a hypothetical cohort of 10,000 people with diabetes. Prevention strategies were assumed to be targeted at individuals with a history of foot ulcer, and benefits were estimated over a period of 3 years. RESULTS: The total potential economic benefits (discounted at 5%) of strategies to reduce amputation risk ranged from $2.0 to $3.0 million ($2,900 to $4,442 per person with a history of foot ulcer) over 3 years. Benefits were highest for educational interventions. Most benefits were found to accrue among individuals aged > or = 70 years. CONCLUSIONS: Strategies to reduce the risk of lower-extremity amputation may generate substantial economic benefits and should be a standard component of routine diabetes care. Benefits may best be achieved through a partnership of government, private payers, health care service providers and producers, and individuals with diabetes.

Age Factors↗
PubMed1998

User interface preferences in a point-of-care data system.

Point-of-care data entry is an important part of a clinical information system. Unfortunately, many health care providers refuse to perform data entry because they feel computers are difficult to use and require more time than traditional paper based forms. We designed a user interface for entry of outpatient visit information that gives the health care provider several alternative methods of entering data. The system audits the use of the individual interface elements and measures the time required for completion of the data entry.

Ambulatory Care Information Systems↗