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Biomedical subjects

D Nichols

Publications and source records attributed to D Nichols.

At least 19 recordsLinked to original sources
PubMed2003

Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment.

BACKGROUND: The management of unruptured intracranial aneurysms is controversial. Investigators from the International Study of Unruptured Intracranial Aneurysms aimed to assess the natural history of unruptured intracranial aneurysms and to measure the risk associated with their repair. METHODS: Centres in the USA, Canada, and Europe enrolled patients for prospective assessment of unruptured aneurysms. Investigators recorded the natural history in patients who did not have surgery, and assessed morbidity and mortality associated with repair of unruptured aneurysms by either open surgery or endovascular procedures. FINDINGS: 4060 patients were assessed-1692 did not have aneurysmal repair, 1917 had open surgery, and 451 had endovascular procedures. 5-year cumulative rupture rates for patients who did not have a history of subarachnoid haemorrhage with aneurysms located in internal carotid artery, anterior communicating or anterior cerebral artery, or middle cerebral artery were 0%, 2. 6%, 14 5%, and 40% for aneurysms less than 7 mm, 7-12 mm, 13-24 mm, and 25 mm or greater, respectively, compared with rates of 2 5%, 14 5%, 18 4%, and 50%, respectively, for the same size categories involving posterior circulation and posterior communicating artery aneurysms. These rates were often equalled or exceeded by the risks associated with surgical or endovascular repair of comparable lesions. Patients' age was a strong predictor of surgical outcome, and the size and location of an aneurysm predict both surgical and endovascular outcomes. INTERPRETATION: Many factors are involved in management of patients with unruptured intracranial aneurysms. Site, size, and group specific risks of the natural history should be compared with site, size, and age-specific risks of repair for each patient.

Age Factors↗
PubMed2003

Extracorporeal shock wave therapy for plantar fasciitis. A double blind randomised controlled trial.

BACKGROUND: Extracorporeal shock wave therapy (ESWT) is an increasingly popular therapeutic approach in the management of a number of tendinopathies. Benefit has been shown in calcific tendinitis of the rotator cuff, but evidence for its use in non-calcific disorders is limited. AIMS: To perform a double blind randomised controlled trial of moderate dose shock wave therapy in plantar fasciitis. METHODS: Adults with plantar fasciitis for at least 3 months were randomised to receive either active treatment (0.12 mJ/mm(2)) or sham therapy, monthly for 3 months. Pain in the day, nocturnal pain and morning start-up pain were assessed at baseline, before each treatment and 1 and 3 months after completion of therapy. RESULTS: Eighty-eight subjects participated and no differences existed between the groups at baseline. At 3 months, 37% of the subjects in the ESWT group and 24% in the sham group showed a positive response (50% improvement from baseline) with respect to pain. Positive responses in night pain occurred in 41% and 31% in the ESWT and sham groups, respectively. Positive responses in start-up pain occurred in 37% and 36% in the ESWT and sham groups, respectively. Both groups showed significant improvement over the course of the study, but no statistically significant difference existed between the groups with respect to the changes were seen in any of the outcome measures over the 6-month period. CONCLUSIONS: There appears to be no treatment effect of moderate dose ESWT in subjects with plantar fasciitis. Efficacy may be highly dependent upon machine types and treatment protocols. Further research is needed to develop evidence based recommendation for the use ESWT in musculoskeletal complaints.

Adult↗
PubMed2002

Prospective randomized trial of low- versus high-dose radiation therapy in adults with supratentorial low-grade glioma: initial report of a North Central Cancer Treatment Group/Radiation Therapy Oncology Group/Eastern Cooperative Oncology Group study.

PURPOSE: To compare survival and toxicity in adult patients treated with low-dose (50.4 Gy/28 fractions) versus high-dose (64.8 Gy/36 fractions) localized radiation therapy (RT) for supratentorial low-grade astrocytoma, oligodendroglioma, and mixed oligoastrocytoma. PATIENTS AND METHODS: From 1986 to 1994, 203 eligible/analyzable patients were randomized: 101 to low-dose RT, 102 to high-dose RT. Almost half were younger than 40 years, and 95% had grade 2 tumors. Histologic subtype was astrocytoma (or mixed oligo-astrocytoma with astrocytoma dominant) in 32% of patients and oligodendroglioma (or oligoastrocytoma with oligodendroglioma dominant) in 68%. Tumor diameter was less than 5 cm in 35% of patients, and 41% of tumors showed some degree of contrast enhancement. Extent of resection was gross total in 14% of patients, subtotal in 35%, and biopsy only in 51%. RESULTS: At the time of the present analysis, 83 patients (41%) are dead, and median follow-up is 6.43 years in the 120 who are still alive. Survival at 2 and 5 years is nonsignificantly better with low-dose RT; survival at 2 and 5 years was 94% and 72%, respectively, with low-dose RT and 85% and 64%, respectively, with high-dose RT (log rank P =.48). Multivariate analysis identified histologic subtype, tumor size, and age as the most significant prognostic factors. Survival is significantly better in patients who are younger than 40 years and in patients who have oligodendroglioma or oligo-dominant histology. Grade 3 to 5 radiation neurotoxicity (necrosis) was observed in seven patients, with one fatality in each treatment arm. The 2-year actuarial incidence of grade 3 to 5 radiation necrosis was 2.5% with low-dose RT and 5% with high-dose RT. CONCLUSION: This phase III prospective randomized trial of low- versus high-dose radiation therapy for adults with supratentorial low-grade astrocytoma, oligodendroglioma, and oligoastrocytoma found somewhat lower survival and slightly higher incidence of radiation necrosis in the high-dose RT arm. The most important prognostic factors for survival are histologic subtype, tumor size, and age. The study design of the ongoing intergroup trial in this population will be discussed.

Adult↗
PubMed2002

Extracorporeal shock wave therapy for lateral epicondylitis--a double blind randomised controlled trial.

UNLABELLED: Extracorporeal shock wave therapy (ESWT) is an increasingly popular therapeutic approach to the treatment of a number of soft tissue complaints. Whilst benefit has been demonstrated in calcific tendinitis, evidence is lacking for benefit in the management of non-calcific rotator cuff disorders. AIMS: To perform a double-blind placebo controlled trial of moderate dose ESWT in chronic lateral epicondylitis. METHODS: Adults with lateral epicondylitis were randomised to receive either active treatment (1500 pulses ESWT at 0.12 mJ/ mm2) or sham therapy, monthly for three months. All were assessed before each treatment and one month after completion of therapy. Outcome measures consisted of visual analogue scores for pain in the day and at night. RESULTS: Seventy-five subjects participated and there were no significant differences between the two groups at baseline. The mean duration of symptoms was 15.9 and 12 months in the ESWT and sham groups, respectively. Both groups showed significant improvements from two months. No significant difference existed between the groups with respect to the degrees of change in pain scores over the study period. In the ESWT group the mean (SD, range) pain score was 73.4 (14.5, 38-99) at baseline and 47.9 (31.4, 3-100) at three months. In the sham group the mean (SD, range) pain score was 67.2 (21.7, 12-100) at baseline and 51.5 (32.5, 3-100) at three months. At three months, 50% improvement from baseline was noted in 35% of the ESWT group and 34% of the sham group with respect to pain. CONCLUSIONS: There appears to be a significant placebo effect of moderate dose ESWT in subjects with lateral epicondylitis but there is no evidence of added benefit of treatment when compared to sham therapy.

Adult↗
PubMed2002

Extracorporeal shock-wave therapy for tendonitis of the rotator cuff. A double-blind, randomised, controlled trial.

We have performed a double-blind placebo-controlled trial of moderate doses of extracorporeal shock-wave therapy (ESWT) for non-calcific tendonitis of the rotator cuff. Adults (74) with chronic tendonitis of the rotator cuff were randomised to receive either active (1500 pulses ESWT at 0.12 mJ/mm2) or sham treatment, monthly for three months. All were assessed before each treatment, and at one and three months after the completion of treatment. The outcome was measured with regard to pain in the shoulder, including a visual analogue score for night pain, and a disability index. There were no significant differences between the two groups before treatment. The mean duration of symptoms in both groups was 23.3 months. Both showed significant and sustained improvements from two months onwards. There was no significant difference between them with respect to change in the Shoulder Pain and Disability Index (SPADI) scores or night pain over the six-month period. A mean (+/-SD; range) change in SPADI of 16.1 +/- 27.2 (0 to 82) in the treatment group and 24.3 +/- 24.8 (-11 to 83) in the sham group was noted at three months. At six months the mean changes were 28.4 +/- 25.9 (-24 to 69) and 30.4 +/- 31.2 (-12 to 88), respectively. Similar results were noted for night pain. We conclude that there is a significant and sustained placebo effect after moderate doses of ESWT in patients with non-calcific tendonitis of the rotator cuff, but there is no evidence of added benefit when compared with sham treatment.

Adult↗
PubMed2001

Assessing pediatric anesthesia practices for volunteer medical services abroad.

BACKGROUND: Anesthetic techniques and problems in volunteer medical services abroad are different from those of either the developed countries from which volunteers originate or the host country in which they serve because of differences in patient population, facilities, and goals for elective surgery. Assessing outcomes is hampered by the transience of medical teams and the global dispersion of providers. We studied general anesthesia techniques and outcomes in a large international voluntary surgical program. METHODS: Anesthesia providers and nurses participating in care of patients undergoing reconstructive plastic and orthopedic surgery by Operation Smile over an 18-month period were asked to complete a quality assurance data record for each case. Incomplete data were supplemented by reviewing the original patient records. RESULTS: General anesthesia was used in 87.1% of the 6,037 cases reviewed. The median age was 5 yr (25th-75th percentiles: 2-9 yr). Orofacial clefts accounted for more than 80% of procedures. Halothane mask induction was performed in 85.6% of patients; 96.3% of patients had tracheal intubation, which was facilitated with a muscle relaxant in 19.3%. Respiratory complications occurred during anesthesia in 5.0% of patients and during recovery (postanesthesia care unit) in 3.3%. Arrhythmias requiring therapy occurred in 1.5%, including three patients to whom cardiopulmonary resuscitation was administered. Prolonged ventilatory support was required in seven patients. There was one death. Inadvertent extubation during surgery occurred in 38 patients. Cancellation of surgery after induction of anesthesia occurred in 25 patients. Overall, complications were more common in younger children. CONCLUSIONS: Our study showed that in this setting it is feasible to track anesthesia practice patterns and adverse perioperative events. We identified issues for further examination.

Adolescent↗
PubMed2001

Sphingomonas alaskensis strain AFO1, an abundant oligotrophic ultramicrobacterium from the North Pacific.

Numerous studies have established the importance of picoplankton (microorganisms of < or =2 microm in length) in energy flow and nutrient cycling in marine oligotrophic environments, and significant effort has been directed at identifying and isolating heterotrophic picoplankton from the world's oceans. Using a method of diluting natural seawater to extinction followed by monthly subculturing for 12 months, a bacterium was isolated that was able to form colonies on solid medium. The strain was isolated from a 10(5) dilution of seawater where the standing bacterial count was 3.1 x 10(5) cells ml(-1). This indicated that the isolate was representative of the most abundant bacteria at the sampling site, 1.5 km from Cape Muroto, Japan. The bacterium was characterized and found to be ultramicrosized (less than 0.1 microm(3)), and the size varied to only a small degree when the cells were starved or grown in rich media. A detailed molecular (16S rRNA sequence, DNA-DNA hybridization, G+C mol%, genome size), chemotaxonomic (lipid analysis, morphology), and physiological (resistance to hydrogen peroxide, heat, and ethanol) characterization of the bacterium revealed that it was a strain of Sphingomonas alaskensis. The type strain, RB2256, was previously isolated from Resurrection Bay, Alaska, and similar isolates have been obtained from the North Sea. The isolation of this species over an extended period, its high abundance at the time of sampling, and its geographical distribution indicate that it has the capacity to proliferate in ocean waters and is therefore likely to be an important contributor in terms of biomass and nutrient cycling in marine environments.

Base Composition↗
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↗