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Biomedical subjects

D Nichols

Publications and source records attributed to D Nichols.

At least 19 recordsLinked to original sources
PubMed2001

Prevalence, clinical manifestations, etiology, and treatment of depression in Parkinson's disease.

To determine the extent to which depression complicates Parkinson's disease (PD), the authors analyzed the literature on depression in PD in order to report on its prevalence, clinical manifestations, and treatment. By means of MEDLINE literature searches, the analysis focused on 45 PD depression studies conducted from 1922 through 1998. The results indicate that the prevalence of depression is 31% for all PD patients. The clinical manifestations of PD depression include apathy, psychomotor retardation, memory impairment, pessimism, irrationality, and suicidal ideation without suicidal behavior. PD depression is effectively treated with a variety of antidepressants, most commonly at present the selective serotonin reuptake inhibitors. Anecdotal evidence supports the use of sertraline to treat PD depression.

Antidepressive Agents↗
PubMed2000

The effect of vitamin-mineral supplementation on the intelligence of American schoolchildren: a randomized, double-blind placebo-controlled trial.

CONTEXT: Many medical, nutrition, and education professionals have long suspected that poor diet impairs the academic performance of Western schoolchildren; academic performance often improves after improved diet. However, others have suggested that such academic gains may be due to psychologic effects rather than nutrition. To resolve this issue, two independent research teams conducted randomized trials in which children were given placebos or low-dose vitamin-mineral tablets designed to raise nutrient intake to the equivalent of a well-balanced diet. Both teams reported significantly greater gains in nonverbal intelligence among the supplemented groups. The findings were important because of the apparent inadequacy of diet they revealed and the magnitude of the potential for increased intelligence. However, none of the ten subsequent replications, or the two original trials, were without limitations leaving this issue in controversy. OBJECTIVES: To determine if schoolchildren who consume low-dose vitamin-mineral tablets will have a significantly larger increase in nonverbal intelligence than children who consume placebos in a study that overcomes the primary criticisms directed at the previous 12 controlled trials. DESIGN: A double-blind, placebo-controlled trial using stratified randomization within each teacher's class based on preintervention nonverbal intelligence. SETTINGS AND SUBJECTS: Two "working class," primarily Hispanic, elementary schools in Phoenix, Arizona, participated in the study. Slightly more than half the teachers in each school distributed the tablets daily to 245 schoolchildren aged 6 to 12 years. INTERVENTION: Daily vitamin-mineral supplementation at 50% of the U.S. daily recommended allowance (RDA) for 3 months versus placebo. OUTCOME MEASURES: Post-test nonverbal IQ, as measured by the Wechsler Intelligence Scale for Children-Revised (WISC-R), while controlling for pretest nonverbal IQ as a covariate. FOUR MAIN RESULTS: First, a significant difference of 2.5 IQ points (95% CI: 1.85-3.15) was found between 125 children given active tablets and 120 children given placebo tablets (p = 0.038). Second, this finding is consistent with the mean 3.2 IQ point net gain found in the 12 similar but less rigorous studies. Third, a significantly higher proportion of children in the active group gained 15 or more IQ points when compared to the placebo group (p < 0.01). Fourth, although 81 matched pairs produced no difference at all in nonverbal IQ gain, the modest 2.5 IQ point net gain for the entire sample can be explained by the remaining 24 children who took active tablets, and had a 16 point higher net gain in IQ than the remaining 19 placebo controls. CONCLUSIONS: This study confirms that vitamin-mineral supplementation modestly raised the nonverbal intelligence of some groups of Western schoolchildren by 2 to 3 points but not that of most Western schoolchildren, presumably because the majority were already adequately nourished. This study also confirms that vitamin-mineral supplementation markedly raises the non-verbal intelligence of a minority of Western schoolchildren, presumably because they were too poorly nourished before supplementation for optimal brain function. Because nonverbal intelligence is closely associated with academic performance, it follows that schools with children who consume substandard diets should find it difficult to produce academic performance equal to those schools with children who consume diets that come closer to providing the nutrients suggested in the U.S. RDA. The parents of schoolchildren whose academic performance is substandard would be well advised to seek a nutritionally oriented physician for assessment of their children's nutritional status as a possible etiology.

Arizona↗
PubMed2000

Detection times and analytical performance of commercial urine opiate immunoassays following heroin administration.

The Federal Workplace Drug Testing Program changed urine screening and confirmation cutoff concentrations for opiate testing from 300 to 2000 ng/mL in 1998. Morphine was the designated target compound. An additional heroin metabolite, 6-acetylmorphine (6-AM), was added to the testing procedure with a cutoff concentration > or = 10 ng/mL. Testing of 6-AM was required if morphine was positive to assist in medical review. A comparison of the new opiate cutoff concentrations was made with the older cutoff concentration at 300 ng/mL. Six commercial opiate immunoassays, four with a 300-ng/mL cutoff, ONLINE, EMIT, CEDIA and AxSym, and two with 2000-ng/mL cutoffs, ONLINE and EMIT, were selected to test 920 urine samples collected from 11 male human subjects following single doses of heroin. Eight received intravenous doses of 3, 6, and 12 mg heroin HCl and four smoked 3.5-, 5.2-, 10.5-, or 13.9-mg doses of heroin (base). In addition, 183 urine-based blind quality-control specimens were added to the study set to assess linearity, cross-reactivity, and interference. Total morphine, free morphine, and 6-AM were measured in each sample by gas chromatography-mass spectrometry (GC-MS). Linearity, cross-reactivity, and interference results for each immunoassay are described. Detection times, sensitivity, specificity, and efficiency of each assay were determined using data from the specimens collected after heroin administration. Detection times for morphine using the 300-ng/mL cutoff assays was approximately 12 h for low dose and 24 to 48 h for higher doses of heroin. For the two 2000-ng/mL cutoff concentration assays detection time was about 12 h. This was also the detection time for 6-AM by GC-MS. ONLINE had the lowest sensitivity, 60-74%, highest specificity, 98.8-100%, and least interference from a selection of common over-the-counter drugs and opioids. Increasing the cutoff to 2000 ng/mL from 300 ng/mL increased efficiencies of the assays from 72.7 to 82.6% to over 97%.

Administration, Inhalation↗
PubMed2000

Activation of the coagulation system in Gulf War Illness: a potential pathophysiologic link with chronic fatigue syndrome. A laboratory approach to diagnosis.

Most symptoms of Gulf War Illness (GWI) are similar to Chronic Fatigue Syndrome (CFS) and/or Fibromyalgia (FM). We investigated whether these symptoms are associated with an activated coagulation system as has been reported in some cases of CFS/FM. The coagulation assays include activation markers of the cascade, platelet activation and hereditary risk factors. Our findings show activation of the coagulation system in GWI. This evidence of a hypercoagulable state suggests that symptoms may be due to poor blood flow and, therefore, a basis for the potential utility of anticoagulant therapy.

Adult↗
PubMed1999

Effect of exercise on postprandial insulin responses in Mexican American and non-Hispanic women.

Postprandial insulin responses (integrated area under the curve) to an oral glucose load after a period of aerobic exercise and no exercise (control) were compared in sedentary normoglycemic Mexican American and non-Hispanic women pair-matched (n = 9) on total body fat mass (21.8 +/- 3.5 kg). The age (27.4 +/- 3.0 years), body mass index (BMI) (23.6 +/- 1.4 kg/m2), waist to hip ratio (WHR) (0.85 +/- .02), waist circumference (83.5 +/- 4.5 cm), lean mass (36.2 +/- 1.5 kg), and maximal O2 consumption ([VO2 max] 32.9 +/- 1.6 mL x kg(-1) x min(-1)) were similar, although the centrality index (subscapular/triceps skinfolds) was significantly greater in Mexican Americans (0.88 +/- 0.06 v 0.70 +/- 0.05, P < .01). Exercise (treadmill walking for 50 minutes at 70% VO2 max) and control trials were performed 4 weeks apart and 5 to 12 days after the onset of menstruation. A 75-g oral glucose load was administered 15 hours after the completion of each trial, with the subjects 12 hours postprandial. Blood samples were drawn prior to glucose ingestion (fasting, 0 minutes) and at minutes 15, 30, 60, 90, 120, and 150 postingestion. The postprandial insulin response was calculated using a trapezoidal method. In Mexican Americans, significant (P < .02) reductions in the postprandial insulin response (exercise v control, 6.5 +/- 1.0 v 8.5 +/- 1.4 pmol/L x min x 10(4)) and fasting insulin (exercise v control, 77.4 +/- 7.0 v 88.5 +/- 10.3 pmol/L) occurred after exercise compared with the control condition. In non-Hispanics, neither the postprandial insulin response (exercise v control, 7.2 +/- 1.0 v 6.2 +/- 0.9 pmol/L x min x 10(4)) nor fasting insulin (exercise v control, 77.0 +/- 8.2 v 82.9 +/- 8.9 pmol/L) were significantly different between trials. The postprandial insulin response in the control trial was significantly correlated with the change in the insulin response (control minus exercise) in the 18 women (r = .56, P = .01). No trial or group differences were found for postprandial glucose and C-peptide responses. Mexican American women have a high risk of developing type 2 diabetes, and aerobic exercise may be valuable in the prevention or delay of onset of diabetes by reducing peripheral insulin resistance.

Adult↗
PubMed1999

Developments with antarctic microorganisms: culture collections, bioactivity screening, taxonomy, PUFA production and cold-adapted enzymes

There have been recent research developments with Antarctic prokaryotes in the areas of isolations of novel bacterial, culture collections, bioactivity screening, taxonomy, production of polyunsaturated fatty acids (PUFAs), cold-adapted enzymes and bioremediation. Research to date confirms the novelty of bacteria isolated from this extreme environment. Opportunities now exist to exploit these and other findings to develop possible new biotechnological products from Antarctic microorganisms.

Journal Article↗
PubMed1998

Evaluation of a bed utilization system in a surgical nursing section.

This research study evaluated a new bed utilization program established in the surgical nursing section at a major military medical facility. The study involved four wards with 83 beds before the new system was implemented, and three wards with 71 beds after the implementation. Five variables were identified as having an effect on the bed management program. These variables were time of discharge, escort compliance, bed availability, staff satisfaction, and patient satisfaction. Both a paired t test and an independent t test were applied for statistical analysis at the 0.05 level of significance. Data were collected for 1 month at two different intervals for comparison, using two surveys, patient records, 24-hour nursing reports, and same-day surgical schedules. A sample size of 103 was used as a basis for time of discharge and staff and patient satisfaction. The staff satisfaction survey also included a demographic data sheet. Escort compliance and bed availability were based on a 30-day time frame. The sample subjects included all patients who entered the surgical nursing section and their health care providers. Data analysis revealed significant differences in escort compliance and bed availability between the pre and post data. Findings from this study support the need for a functional, efficient bed management system.

Adolescent↗
PubMed1997

Static and dynamic balance responses in persons with bilateral knee osteoarthritis.

Research has documented decreased strength and proprioception in people with arthritis. Both are components of balance, but reliable studies documenting balance deficits have not been done. This study tested standing balance in an adult population with osteoarthritis. The osteoarthritic group (N = 11) and the age-matched control group (N = 10) were tested on the Balance System. Each underwent two trials of six testing conditions [two visual conditions (eyes open, eyes closed) under each of three platform conditions (stable, angular rotation, and linear translation)] and completed a functional assessment scale. Individuals with knee osteoarthritis demonstrated significantly more postural sway than the control group across conditions (p < 0.02). The functional assessment scale developed to discriminate between the two groups demonstrated internal consistency (Cronbach's coefficient alpha = 0.83), and scores were significantly different between the two groups (p < 0.0001). Results suggest the importance of balance training in this population. The functional assessment scale may be a useful tool to document functional levels in knee osteoarthritis.

Accidental Falls↗
PubMed1997

Reflex Sympathetic Dystrophy in the Upper Extremity.

The diagnosis and treatment of pain are among the most challenging problems facing orthopaedic surgeons, and reflex sympathetic dystrophy is probably the most frustrating and difficult pain syndrome to manage. Pain, swelling, and autonomic dysfunction are cardinal signs of the condition. Although the pathogenesis is still unclear, many theories have been proposed. Because reflex sympathetic dystrophy is sympathetically mediated, diagnosis can be confirmed on the basis of response of the pain to sympathetic blockade. Treatment may include an appropriate exercise program, a-adrenergic blocking agents, mood-elevating drugs, calcium channel blockers, intravenous regional blocks, and stellate ganglion blocks. Recent additions to therapy include electroacupuncture, transcutaneous electrical nerve stimulation, and biofeedback. Prognosis is, at best, guarded with this perplexing condition, but the best response is obtained when diagnosis is made early (within the first 2 or 3 weeks after injury) and treatment is initiated during the first stage of the disease.

Journal Article↗
PubMed1997

[Molecular modeling of N-isopropyl lisergamides analogous to LSD using molecular mechanics and quantum mechanical calculations].

Molecular mechanics and quantum mechanics were used to study the preferred conformations, electron densities and frontier orbitals of d-LSD and their analogs with the isopropyl amide group, compounds with reported activity over the serotonin receptor. Electron densities and frontier orbitals for isopropyl analogs were similar to d-LSD, so these properties can not be related with the changes in biological activity previously reported. It was found that isopropyl analogs have preferred conformations similar to d-LSD with small variation in the alkylamide group. The variation in the alkylamide group causes small variations in the orientation of the carbonyl amide group, our study suggests that this variation could affect the binding with the hydrophobic region of the receptor.

Hallucinogens↗