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Biomedical subjects

D King

Publications and source records attributed to D King.

At least 127 records · Page 7Linked to original sources
PubMed1997

Qualitative MR imaging of refractory temporal lobe epilepsy requiring surgery: correlation with pathology and seizure outcome after surgery.

OBJECTIVE: The purpose of this study was to compare MR imaging findings with histologic findings of either hippocampal sclerosis or gliosis in patients with intractable temporal lobe epilepsy requiring surgery and to correlate MR imaging findings with seizure outcome after surgery and with clinical parameters such as febrile seizure history. MATERIALS AND METHODS: A retrospective study of MR scans of 66 patients with medically refractory temporal lobe epilepsy requiring surgery was performed. Qualitative diagnosis was done by visual inspection of MR images. MR imaging findings of hippocampal atrophy, signal intensity changes, and segmental findings were correlated with histopathology and with neuronal density. The final MR imaging diagnosis was also correlated with seizure outcome after surgery and with febrile seizure history. RESULTS: Histologic findings consisted of hippocampal sclerosis in 55 patients and nonspecific gliosis in 11 patients. Two variables, MR imaging findings of hippocampal sclerosis (hippocampal atrophy or signal intensity change) and a febrile seizure history, were significantly associated with hippocampal sclerosis. MR images of nonspecific gliosis usually showed normal findings, although some cases showed mild hippocampal atrophy. When comparing MR imaging findings with histology, our observers achieved sensitivities of 87-98% and specificities of 45-100%. In patients with successful outcomes after surgery, sensitivity ranged from 85% to 98% for MR imaging findings suggesting hippocampal sclerosis, specificity ranged from 17% to 85%, and positive predictive values ranged from 82% to 90%. CONCLUSION: Qualitative visual analysis of MR images correlates well with histologic findings, febrile seizure history, and seizure outcome after surgery. MR imaging findings and febrile seizure history help differentiate between hippocampal sclerosis and nonspecific gliosis, two similar clinical conditions associated with temporal lobe epilepsy that often have different outcomes after surgery.

Adolescent↗
PubMed1997

Doctors' knowledge of post-splenectomy prophylaxis.

A questionnaire was sent to 160 hospital doctors and 200 general practitioners about post-splenectomy prophylaxis during the month of September 1995. A total of 118 questionnaires were returned (43% hospital doctors and 25% GPs). Most doctors (99%) knew that splenectomised patients were at risk of pneumococcal infection; 72% of hospital doctors and 50% of GPs knew of the risk of Haemophilus influenza infection but only 50% of hospital doctors and 33% of GPs knew of the same risks involving meningococcal infection and malaria. Half of the GPs were not aware of H. influenzae type B (Hib) vaccine for prophylaxis and 85% of these and 50% of hospital doctors did not know prophylaxis should be lifelong. There was no significant difference in the knowledge between hospital doctors and GPs.

Anti-Bacterial Agents↗
PubMed1996

Meta-analysis of respiratory rehabilitation in chronic obstructive pulmonary disease.

BACKGROUND: Respiratory rehabilitation is increasingly recognised as an important part of the management of patients with chronic obstructive pulmonary disease (COPD). The widespread application of such programmes should be preceded by evidence of directly attributable improvements in function. We assessed the effect of respiratory rehabilitation on exercise capacity and health-related quality of life (HRQL) in patients with COPD. METHODS: We carried out a meta-analysis of randomised controlled trials of respiratory rehabilitation in patients with COPD that assessed functional or maximal exercise capacity, HRQL, or both. Respiratory rehabilitation was defined as exercise training (for at least 4 weeks) with or without education, psychological support, or both. The most commonly used measure for HRQL was the chronic respiratory questionnaire, in which responses were presented on a 7-point scale. The control groups received no rehabilitation. Within each trial and for each outcome an effect size was calculated; the effect sizes were then pooled by a random-effects model. The overall effect of treatment was compared with its minimum clinically important difference (MCID)--defined as the smallest difference perceived as important by the average patient. FINDINGS: We included 14 trials. Significant improvements were found for all the outcomes. For two important features of HRQL, dyspnoea and mastery, the overall treatment effect was larger than the MCID: 1.0 (95% CI 0.6-1.5) and 0.8 (0.5-1.2), respectively, compared with an MCID of 0.5. For functional exercise capacity (6-min walk test), the overall effect was 55.7 m (27.8-92.8), and for maximum exercise capacity (incremental cycle ergometer test), 8.3 W (2.8-16.5). Functional exercise capacity showed heterogeneity that could not be explained by the sensitivity analyses. INTERPRETATION: Respiratory rehabilitation relieves dyspnoea and improves the control over COPD. These improvements are clinically important. The value of the improvement in exercise capacity is not clear. Respiratory rehabilitation is an effective part of care in patients with COPD.

Exercise Therapy↗
PubMed1996

Educational and gender normative data for the Boston Naming Test in a group of older adults.

The 60-item version of the Boston Naming Test (BNT) was administered to a group of 176 normal older adults in Middle Tennessee ranging in age from 60 to 93 years. Results are reported in five age groupings by gender and education. Although a few studies have previously examined the performance of the elderly on the BNT, the current study attempted to recruit individuals in proportion to the demographics of the regional population including gender, race, and, as much as possible, education and occupation. The results indicate that while age significantly affected confrontational naming ability, the interaction of age and education appeared to be a better predictor of performance. As with previous studies, more variability was found in higher age groups and in those with less education. Naming ability remained stable in the higher education group (> or = 12th grade) until 80 years, whereas those patients with less than a high school education demonstrated a decrement in naming ability at 70 years. Current results also revealed a gender bias for this population, with males scoring higher on 17 of 19 items where a significant difference existed.

Aged↗
PubMed1996

Impaired gastric emptying in mechanically ventilated, critically ill patients.

OBJECTIVE: To measure gastric emptying in critically ill patients using an acetaminophen absorption model and determine which variables are associated with impaired gastric emptying. DESIGN: A prospective, cohort study. SETTING: A medical/surgical ICU at a tertiary care hospital: Hamilton General Hospital, Hamilton, Ontario. PATIENTS AND PARTICIPANTS: We recruited 72 mechanically ventilated patients expected to remain in the ICU for more than 48 h. Our results were compared to those in healthy volunteers. INTERVENTION: Within 48 h of admission to the ICU, 1.6 g acetaminophen suspension were administered via a nasogastric tube into the stomach. Blood samples were drawn a t = 0, 30, 60, 90, and 120 min for measurement of plasma acetaminophen levels determined by the enzymatic degradation method. MEASUREMENTS AND RESULTS: Maximal concentration of acetaminophen was 94.1 (75.3) mumol/l compared to 208.4 (33.1) mumol/l in a control population (p < 0.0001). The time to reach the maximal concentration was 105 min (60-180) compared to 30 min (15-90) in controls (p < 0.0001). The area under the time-acetaminophen concentration curve t = 120 was 9301 (7343) mumol/min per l compared to 11644 (1336) mumol/min per l in the controls (p = 0.28). The variables associated with delayed gastric emptying were age, sex and use of opioids for analgesia and sedation. CONCLUSIONS: Gastric emptying is delayed in critically ill patients. The important consequences of this phenomenon include intolerance to enteral nutrition and gastric colonization. Strategies to minimize the use of narcotics may improve gastric emptying. Studies to examine the effect of gastrointestinal prokinetic agents on gastric emptying are needed.

Acetaminophen↗
PubMed1996

Discrimination and abuse in internal medicine residency. The Internal Medicine Program Directors of Canada.

OBJECTIVE: To survey the extent to which internal medicine housestaff experience abuse and discrimination in their training. DESIGN: Through a literature review and resident focus groups, we developed a self-administered questionnaire. In this cross-sectional survey, respondents were asked to record the frequency with which they experienced and witnessed different types of abuse and discrimination during residency training, using a 7-point Likert scale. PARTICIPANTS: Internal medicine housestaff in Canada. MEASUREMENTS AND MAIN RESULTS: Of 543 residents in 13 programs participating (84% response rate), 35% were female. Psychological abuse, as reported by attending physicians (68%), patients (79%), and nurses or other health workers (77%), was widespread. Female residents experienced gender discrimination by attending physicians (70%), patients (88%), and nurses (71%); rates for males were 23%, 38%, and 35%, respectively. Females reported being sexually harassed more often than males, by attending physicians (35% vs 4%, p < .01), peers (30% vs 6%, p < .01), and patients (56% vs 18%, p < .01). Physical assault by patients was experienced by 40% of residents. Half of the residents surveyed reported racial discrimination and homophobic remarks in the workplace, perpetrated by all groups of health professionals. CONCLUSIONS: Psychological abuse, gender discrimination, sexual harassment, physical abuse, homophobia, and racial discrimination are prevalent problems during residency training. Housestaff, medical educators, allied health workers, and the public need to work together to address these problems in the training environment.

Adult↗
PubMed1996

Possible confounding effects of strobe "clicks" on flash evoked potentials in rats.

Flash evoked potentials (FEPs) undergo within- and between-session changes and are modified by auditory white noise (26). We examined whether an auditory potential produced by the "click" associated with the strobe discharge could be recorded, and if alterations in an auditory response could explain the within- and between-session changes in FEPs. We also examined differences between a frontal cortex or a nasal reference electrode location on FEPs and auditory potentials. An auditory potential associated with the strobe discharge could be clearly recorded. This response was eliminated by the presence of 80 dB SPL masking white noise. However, the within- and between-session changes in FEPs could not be explained by modifications of the auditory potential. Animals whose ear drums were ruptured did not exhibit an auditory response, and their FEPs were similar to those of controls tested in the presence of masking white noise. A nasal reference electrode decreased the impact of auditory potentials on FEPs, but allow visual potentials (electroretinogram and optic tract activity) to influence FEPs. The data show that auditory potentials associated with the strobe discharge can be recorded from the visual cortex of rats, and that these auditory responses represent a possible confounding factor in the interpretation of toxicological studies employing FEPs.

Acoustic Stimulation↗
PubMed1996

Erythroid-specific expression of human growth hormone affects bone morphology in transgenic mice.

The regulation of bone deposition and remodeling is highly complex. To further understand the influence of growth hormone on bone deposition, several lines of transgenic mice were generated that expressed the human growth hormone gene (hGH) driven by beta-globin regulatory elements. In situ hybridization confirmed that the hGH gene in these mice was expressed in an erythroid tissue-specific manner; in the fetus hGH was expressed in the liver and in the adult mice hGH was expressed in the bone marrow. The bones of mice in two lines were visualized radiographically by mammography, and relative bone densities were measured. The transgenic mice had detectably more bone density than nontransgenic littermate controls by approximately 3 weeks of age and the relative difference in density increased with age. Histological cross-sections of the tibia showed that adult transgenic mice had increased average cortical bone thickness when compared to their controls. The hypothesis is that the local effect of hGH release from differentiating erythroid cells in the bone marrow is a major contributor to the increased bone deposition in these transgenic mice.

Animals↗
PubMed1996

Heterozygous oim mice exhibit a mild form of osteogenesis imperfecta.

The oim strain of mice is one of several rodent models that exhibit an osteogenesis imperfecta (OI) phenotype. These mice have a mutation in the gene encoding alpha-2 chain of type I procollagen that prevents proper assembly of this propeptide with alpha-1 propeptides. Homozygous oim mice experience multiple bone fractures under standard laboratory animal housing conditions and are representative of moderate to severe forms of OI. Because fractures are not typically experienced by heterozygous oim mice, they have not been studied extensively. The present studies show that the organization of cortical bone is deficient in heterozygotes, exhibiting a morphology intermediate to specimens from homozygotes and wild-type mice. The biomechanical properties of femurs isolated from heterozygous oim mice are also intermediate to homozygotes and wild-type mice when tested in four-point bending. Although it is not possible to distinguish visually between heterozygous oim and wild-type mice, the quality and biomechanical properties of bone in heterozygotes is significantly reduced by twelve weeks of age. Heterozygous oim mice are useful as a model for a mild form of OI.

Animals↗
PubMed1996

Severe global amnesia presenting as Wernicke-Korsakoff syndrome but resulting from atypical lesions.

A female alcoholic presented with Wernicke's encephalopathy subsequent to administration of diazepam and glucose (without thiamine) for treatment of withdrawal seizures. Nystagmus and cerebellar ataxia quickly resolved when administered thiamine, although severe global amnesia consistent with Korsakoff's syndrome persisted. Magnetic resonance imaging (MRI) revealed infarction of the right temporal lobe with hippocampal atrophy, but no lesions of thalamus or atrophy of mammillary bodies. Positron emission tomography (PET) confirmed decreased cerebral metabolic rates for glucose (CMRglu) in the right temporal lobe corresponding to MRI findings, but also significant metabolic asymmetry of dorsal thalamus, i.e. reduced CMRglu in left versus right. This patient is unique in that neuroradiological findings revealed intact mammillary bodies and suggest asymmetrical dysfunctions (structural right temporal and functional left diencephalic) to produce her profound amnesia.

Alcohol Amnestic Disorder↗
PubMed1996

Fat malabsorption in elderly patients with cardiac cachexia.

Malnutrition resulting from chronic congestive heart failure (cardiac cachexia, CC) is not uncommon and contributes to mortality and morbidity especially of elderly people. The aetiology of cardiac cachexia is probably multifactorial. We have assessed whether malabsorption of fat is associated with CC and if so whether it is due to small-bowel bacterial overgrowth. Three groups of subjects were studied: 29 (20 women) patients (mean age 76.1 years) with controlled congestive heart failure and weight loss (CC); 14 (seven women) patients (mean age 74.0 years) with controlled congestive heart failure and no weight loss (non-cachexia, NON-CC); and 29 (20 women) healthy controls (mean age 74.9 years). Fast absorption was quantified using the cumulative 6 h 14CO2 exhalation in the 14C-triolein breath test and small-bowel bacterial overgrowth was quantified using the cumulative 8 h 14CO2 exhalation in the 14C-glycocholic acid breath test. The cumulative 6 h 14CO2 exhalation in the triolein breath test was reduced in the CC group (p = 0.001) implying impaired fat absorption. There was no evidence of small-bowel bacterial overgrowth in any group. Impaired absorption of fat was related to the clinical severity of heart failure and its duration. Impaired fat absorption is associated with cardiac cachexia. It is not due to small-bowel bacterial overgrowth. The aetiology of fat malabsorption in heart failure requires further studies.

Aged↗
PubMed1996

Gastro-intestinal protein loss in elderly patients with cardiac cachexia.

Undernutrition resulting from chronic congestive heart failure (cardiac cachexia, CC) increases morbidity and mortality particularly in elderly people. The aetiology of CC is thought to be multifactorial. We have assessed the presence of gastro-intestinal protein loss in a group of patients with CC and a group of healthy age-and sex-matched controls. Gastro-intestinal protein loss was measured using the chromic chloride test in 29 patients with CC [mean age 76.1 (SD4.4) years] and 29 healthy controls [mean age 74.9 (SD 4.8) years]. The patients were undernourished in terms of anthropometric measurements compared to controls. The patients had a significantly lower mean ejection fraction [41.5(18.3)% vs. 65.5(2. 2)%] and higher mean pulmonary artery pressure [89.4(19.9)mmHg vs. 19.3(8.1) mmHg]. The recovery of radioactivity in a 5-day stool collection was similar in the two groups [patients vs. controls: 1. 0(0.7)% vs. 0.98(0.6)%, p=0.9]. These values are within the expected normal range. We conclude that gastro-intestinal protein loss is not a significant factor in the production of cardiac cachexia.

Aged↗
PubMed1996

Maximizing oxygen delivery in critically ill patients: a methodologic appraisal of the evidence.

OBJECTIVE: To systemically review the effect of interventions designed to achieve supraphysiologic values of cardiac index, oxygen delivery (DO2), and oxygen consumption (VO2) in critically ill patients. DATA SOURCES: Computerized bibliographic search of published research, citation review of relevant articles, and contact with primary investigators. STUDY SELECTION: We included all randomized clinical trials of adult intensive care unit (ICU) patients that evaluated interventions (fluids, inotropes, and vasoactive drugs) designed to achieve supraphysiologic values of cardiac index, DO2, and/or VO2. Independent review of 64 articles identified seven relevant studies of 1,016 patients. DATA EXTRACTION: We abstracted data on the population, interventions, outcomes, and methodologic quality of the studies by duplicate independent review. Agreement was high (weighed kappa 0.73); differences were resolved by consensus. DATA SYNTHESIS: Targeting therapy to achieve supraphysiologic end points in critically ill patients is associated with a nonstatistically significant trend toward decreased mortality rates (relative risk 0.86, 95% confidence intervals 0.62 to 1.20). For the two studies in which supraphysiologic goals were initiated preoperatively, the relative risk was 0.20 (95% confidence intervals 0.07 to 0.55). This value differed significantly from the combined estimate of the remaining studies, in which the intervention was started after ICU admission (relative risk 0.98, 95% confidence intervals 0.79 to 1.22; p<.01). However, there are several methodologic problems with the primary studies. In no trials were caregivers or outcome assessors blinded to treatment allocation. Only three of seven trials analyzed patients according to the group to which they were allocated. None adequately controlled for cointerventions, and there was considerable crossover between groups (patients in the control group achieved the goals of the intervention group and vice versa). CONCLUSIONS: Interventions designed to achieve supraphysiologic goals of cardiac index, DO2, and VO2 did not significantly reduce mortality rates in all critically ill patients. However, there may be a benefit in those patients in which the therapy is initiated preoperatively. Methodologic limitations weaken the inferences that can be drawn from these studies and preclude any evidence-based clinical recommendations.

Adult↗
PubMed1996

Serial changes in serum vitamin K1, triglyceride, cholesterol, osteocalcin and 25-hydroxyvitamin D3 in patients after hip replacement for fractured neck of femur or osteoarthritis.

Serum vitamin K1 concentrations were measured at presentation (just before surgery) and then at weekly intervals for 3 weeks in two groups of elderly patients requiring either hemiarthroplasty for fractured neck of femur (FON, n = 13) or total hip replacement for osteoarthritis of the hip (OA, n = 16). In comparison with healthy elderly volunteers (n = 25), serum vitamin K1 concentrations were significantly lower in both groups at presentation, and fell significantly within 24 h after surgery to concentrations approaching non-detectable, subsequently returning to pre-operative values within 3 weeks. Serum vitamin K1 tended to be lower in the fracture group both before and after operation, although calculation of a vitamin K1-triglyceride ratio reduced the apparent difference as triglyceride concentrations were lower in the fracture group. Osteocalcin concentrations were similar and fell significantly after operation in both groups, returning to pre-operative levels within 7 days. No differences in the two forms of osteocalcin (carboxylated and undercarboxylated) were observed either before or after operation in either group. 25-Hydroxyvitamin D3 concentrations were not significantly different between the two groups at any time. Vitamin K1 status may be lower than desirable in certain groups of the elderly population, and supplementation should be considered as prophylactic therapy.

Aged↗
PubMed1996

Primary invasive cutaneous Microsporum canis infections in immunocompromised patients.

Two cases of primary invasive cutaneous infections caused by the zoophilic dermatophytic species Microsporum canis are presented. The first case occurred in a liver transplant recipient who was receiving immunosuppressive therapy. Multiple erythematous papules were seen on both legs, and a biopsy revealed invasive fungal hyphae. The second case was diagnosed in a human immunodeficiency virus-positive individual with a CD4 lymphocyte count of 81 mm3. Raised red nodules were seen on her scalp and face. Histopathology was consistent with bacillary angiomatosis, and in addition, invasive septate hyphae were observed. The two strains recovered from the biopsy specimens from both individuals had colony morphologies consistent with that of M. canis, but it was difficult to induce production of macroconidia. These cases serve to increase the awareness of this unusual infection, reinforce the need for cultures, and raise some interesting questions about the potential virulence of this dermatophyte species.

AIDS-Related Opportunistic Infections↗
PubMed1996

Intestinal permeability and orocaecal transit time in elderly patients with Parkinson's disease.

The aetiology of weight loss in patients with Parkinson's disease is likely to be multifactorial. We studied 15 patients with Parkinson's disease and 15 age- and sex-matched controls and looked for evidence of malabsorption due to small bowel bacterial overgrowth or alteration of intestinal permeability. There was a marked increase in orocaecal transit time in the patients with Parkinson's disease, although lactulose hydrogen breath testing did not show evidence of small bowel bacterial contamination. Intestinal permeability measured by the differential sugar absorption test was also deranged. There was reduced absorption of mannitol in patients with Parkinson's disease while lactulose absorption was similar in both groups, suggesting decreased non-mediated uptake across the enterocyte brush border membrane in patients with Parkinson's disease.

Aged↗