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Biomedical subjects

J Roberts

Publications and source records attributed to J Roberts.

At least 127 records · Page 7Linked to original sources
PubMed1999

Mobility in old age.

Immobility is common in older people and may impact on their dental care. Immobility in old age may have physical, psychological and environmental causes. Immobile elderly people often suffer from a number of diseases which worsen their mobility. Arthritis, osteoporosis, hip fracture, stroke and Parkinson's disease are among the most common causes of immobility in old age. Complications of immobility such as orthostatic hypotension may occur in the dental patient. Careful history-taking and a thorough physical examination by the physician are the most important parts of the assessment process. This assessment should lead to a list of active problems and treatment should then be aimed at these problems. Active management, carried out by the multidisciplinary team, will lead to improvements in mobility and lessen the frequency and severity of the complications of immobility. This broad description thus provides the basis for a wide understanding for the special problems that the immobile patient present to the practitioner and ways of overcoming the problems.

Aged↗
PubMed1999

Effect of diet on thoroughbred horses with recurrent exertional rhabdomyolysis performing a standardised exercise test.

Previous studies have associated recurrent exertional rhabdomyolysis (RER) with a diet high in soluble carbohydrate (CHO). The purpose of this study was to investigate the effect of 3 diets on clinical and metabolic parameters in 5 Thoroughbred horses with RER and 3 healthy Thoroughbreds performing a standardised exercise test (SET). Two diets were formulated to meet energy requirements for the amount of exercise being performed in the form of CHO or fat (21.4 Mcal DE/day). The third diet was formulated to provide 135% of the DE of the other 2 diets in the form of an excessive amount of carbohydrate (28.8 Mcal DE/day). Diets were fed in a crossover design for 3 week blocks and then horses performed a near maximal SET. Changes in heart rate (HR), plasma lactate, plasma glucose, total plasma solids, packed cell volume (PCV), muscle lactate and muscle glycogen concentration were measured immediately prior to, during, and 5 min after exercise. Serum creatine kinase (CK) activity was measured prior to and 4 h post SET. A 2-way ANOVA was used to examine the effect of group and dietary treatment. When dietary treatments were compared, horses fed the high-CHO diet had a mean pre-SET PCV and pre-SET HR that was higher than horses fed the fat diet (P = 0.06 and P = 0.07, respectively). Pre-SET heart rates were highest in RER horses consuming the high-CHO diet compared to RER horses consuming the low-CHO and fat diets (P = 0.02). Horses with RER had 4 h post SET CK activity greater than 400 u/l in 7/14 (50%) measurements compared to control horses which had CK activity greater than 400 u/l in 2/7 (29%) measurements. This study did not demonstrate a significant effect of diet on rhabdomyolysis, indicated by CK activity, or on the metabolic response to exercise. However, diet may have a calming effect on Thoroughbred horses with RER as manifested by decreased pre-exercise heart rates and decreased pre-exercise PCV in horses fed the fat diet.

Animals↗
PubMed1999

Adoption of a managerial innovation: a study of physician impact analysis.

This article examines the adoption of physician impact analysis (PIA) among active treatment hospitals in Ontario, Canada. The influence of variables from three different levels of analysis (individual, organizational and contextual) were included as well as measures of key stakeholders' (Chief Executive Officer (CEO) and Medical Chief of Staff) assessments of the attributes of the innovation. A number of conclusions were drawn. First, by adding information about the perceived attributes of the innovation the model was able to account for a larger percentage of explained variance than has been seen in related work. Secondly, the adoption of PIA within a context of written guidelines agreed to by senior management, specifying process and structure concerns, is most likely in organizations which are large and where the CEO positively evaluates the innovation.

Chief Executive Officers, Hospital↗
PubMed1999

Behavior states: now you see them, now you don't.

Guess, Roberts, Behrens, and Rues (1998) presented reliability data from recordings of behavior state using a 13-category coding system. Interobserver agreement was reported at 63% to 91% across categories. In an attempt at replication, we found lower levels of reliability (0% to 80%). To determine the reasons for different results, we obtained measurements of behavior states from video-recordings by five of Guess et al.'s observers. Again, replication was unsuccessful. Obtained mean percentage agreement on occurrence for individual behavior states and participants ranged across observer pairs from 0% to 58% (kappa range was 0 to .64). Some possible reasons for failures to replicate are discussed.

Humans↗
PubMed1999

Resurgence of sleeping sickness in Tambura County, Sudan.

Endemic foci of human African trypanosomiasis are present in southern Sudan. In 1996 and 1997, trypanosomiasis increased sharply in Tambura County. To define the magnitude and geographic distribution of the outbreak, we conducted a prevalence survey using population-based cluster sampling in 16 villages: 1,358 participants answered questions about routine activities and tsetse fly contact and received serologic testing. Seroprevalence in the surveyed area was 19.4% (95% confidence interval = 16.9%, 21.8%). We confirmed infection in 66% of seropositive persons who received one parasitologic examination and in 95% of those who had serial examinations of lymph node fluid and blood. Activities related to the civil war, such as temporary migration, were not associated with seropositive status. Since the previous population screening in 1988, the trypanosomiasis prevalence increased two orders of magnitude, and the proportion of villages affected increased from 54% to 100%. Our results suggest that there may be 5,000 cases in Tambura County. The absence of trypanosomiasis control for nearly a decade is a factor in the resurgence of the disease.

Adolescent↗
PubMed1999

Concurrent paclitaxel and thoracic irradiation for locally advanced esophageal cancer.

Esophageal cancer is a major cause of morbidity and mortality worldwide. Although patients often present with apparently resectable disease, systemic spread frequently occurs before the development of symptoms and detection of tumor. The use of combined chemoradiation therapy, particularly before resection, appears to prolong survival and increase cure rates in certain histologic subtypes. Four randomized phase III trials compared preoperative chemoradiotherapy plus surgery with surgery alone. In trials including only patients with squamous histology, no improvement in survival was observed with preoperative chemoradiation therapy; however, in a trial including only patients with adenocarcinoma histology, improved median and overall survival were observed. Paclitaxel has been evaluated as a single agent in a phase II trial in previously untreated patients with locally advanced unresectable or metastatic esophageal cancer; the overall response rate was 32% and median survival was 13.2 months. Paclitaxel-based combinations also have been evaluated in esophageal cancer; particularly encouraging preliminary results have been achieved with paclitaxel/cisplatin/5-fluorouracil. Because paclitaxel is a potent radiosensitizer, it also has been evaluated in combination with radiation therapy for esophageal and other thoracic cancers, alone and in combination with other chemotherapeutic agents. Preliminary results suggest that neoadjuvant therapy with paclitaxel-based combinations (including 5-fluorouracil and cisplatin) and radiation is highly active, with variable toxicity. A goal of future trials is to assess paclitaxel-based combined modality therapy in combination with other new chemotherapeutic agents.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Are healthcare professionals really prepared to deal with information-empowered citizens?

The new Global Information Society increasingly incorporates electronic tools in every walk of life. The e-communication revolution should not be welcomed just because it exists, but rather taken as a possible catalyst to better performance, however that is perceived. Healthcare practitioners must harness the good will & motivation of citizens to play proactive parts in the health & lifestyle management for themselves, their families & their communities. Citizens must recognise that they do not become 'experts' overnight & must work with professional practitioners to the benefit of health status per se. There are still a number of substantial challenges to be faced & a need for considerable parallel & collective development if we (professionals & public) are to contribute effectively together in healthcare in the future.

Health Education↗
PubMed1998

Evidence for regulated expression of neuropeptide Y gene by rat and human cultured astrocytes.

A series of studies from our laboratory have established that fetal rat and human neuropeptide Y (NPY) cortical neurons in aggregate cultures are differentially regulated. In a preliminary study we found that primary astrocytes produce substantial amounts of immunoreactive (IR) NPY. We addressed the question: Is astrocyte production of NPY-IR a regulated process? The effects of brain-derived neurotrophic factor (BDNF, 50 ng/ml), basic fibroblast growth factor (bFGF), substance P (1 microM), forskolin (10 microM), or phorbol 12-myristate-13-acetate (PMA, 20 nM) on NPY-IR production was tested on rat and human primary astrocyte cultures. Of these agents, PMA and bFGF markedly induced NPY-IR production by rat as well as human astrocytes, forskolin induced NPY-IR production by human but not rat astrocytes, and neither BDNF nor substance P induced NPY-IR production by rat or human astrocytes. The molecular size of PMA-induced NPY-IR was found to be consistent with that of proNPY. Moreover, PMA induced the accumulation of mRNA corresponding in size to the neuronal NPY-mRNA. Immunocytochemical analysis of human post-mortem neocortex revealed co-existence of NPY-IR with astrocyte markers. These results indicate that cultured astrocytes express NPY gene in a regulated manner and they support our proposition that in situ reactive astrocytes may express NPY gene under some physiological/pathological conditions.

Animals↗
PubMed1998

Surviving social assistance: 12-month prevalence of depression in sole-support parents receiving social assistance.

BACKGROUND: Although it is generally recognized that poverty and depression can coexist among single parents receiving social assistance, there is insufficient research on this topic. The goals of this study therefore were to investigate the prevalence, correlates and health care expenditures associated with depression among sole-support parents receiving social assistance. METHODS: Sole-support parents who had applied for social assistance in 2 regions of southwestern Ontario were included in the study. Depression was diagnosed with the 1994 University of Michigan Composite International Diagnostic Interview short forms. RESULTS: The 12-month prevalence rate of depressive disorder among the parents interviewed was 45.4% (345/760). A total of 247 (32.5%) had major depressive disorder alone, 19 (2.5%) had dysthymia, and 79 (10.4%) had both major depressive disorder and dysthymia ("double depression"). Those with major depressive disorder, particularly double depression, had significantly higher rates of coexisting psychiatric disorder than those without depressive disorders. Parents with depression reported higher rates of developmental delay and behaviour problems in their children than parents without depression. Expenditures for health care services were higher for parents with depression and for their children than for parents without depressive disorder and their children. INTERPRETATION: Single parents receiving social assistance have high rates of depression. Such parents with depression also have higher rates of other psychiatric disorders and higher expenditures for health care services, and their children have higher rates of developmental delay and behaviour problems.

Adaptation, Psychological↗
PubMed1998

Targeted intraparenchymal delivery of human NGF by gene transfer to the primate basal forebrain for 3 months does not accelerate beta-amyloid plaque deposition.

Nerve growth factor therapy has been proposed as a potential means of preventing degeneration of basal forebrain cholinergic neurons in Alzheimer's disease and thereby improving cognition. However, NGF has been reported to upregulate expression of the beta-amyloid precursor protein, which in turn could accelerate deposition of "mature" beta-amyloid in the brain. To address this possibility, the brains of 16 adult and aged rhesus monkeys were examined for beta-amyloid plaque deposition in the presence or absence of NGF treatment. Six aged monkeys received intraparenchymal grafts into the cholinergic basal forebrain of autologous cells genetically modified to secrete NGF, six aged monkeys received intraparenchymal grafts of autologous control cells expressing the reporter gene beta-galactosidase, and four adult nonoperated monkeys served as additional controls. All brains were examined for expression of mature beta-amyloid using an antibody recognizing amino acids 1-40 of the beta-amyloid peptide. Amyloid plaques were systematically quantified in representative sections of the temporal, frontal, cingulate, insular, and parietal cortices and in the amygdala and hippocampus. Results disclosed that aging resulted in an increase in amyloid plaque formation: no plaques at all were detected in nonaged monkeys, whereas a mean of 20 +/- 13 plaques per section were present in control-aged monkeys. Aged subjects with intraparenchymal NGF-secreting grafts for 3 months contained a mean of 29 +/- 14 plaques per section, an amount that did not differ significantly from control-aged monkeys (P = 0.66). Thus, 3 months of intraparenchymal NGF delivery did not significantly increase beta-amyloid deposition.

Aging↗
PubMed1998

Predictors of pre-eclampsia in women at high risk. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units.

OBJECTIVE: We assessed several variables as predictors for pre-eclampsia risk in a group of women at high risk. STUDY DESIGN: We studied 2503 women with either diabetes mellitus, chronic hypertension, multifetal gestation, or pre-eclampsia in a previous pregnancy who participated in a multicenter study comparing aspirin and placebo in preventing pre-eclampsia. We evaluated multiple variables for predicting pre-eclampsia risk with use of univariate and multivariable analysis. RESULTS: Parity and mean arterial pressure at randomization were most predictive of pre-eclampsia risk. The risk was 8% with a mean arterial pressure at enrollment of <75 mm Hg versus 27% with a mean arterial pressure >85 mm Hg (relative risk and 95% confidence interval 3.3 [2.4 to 4.4]). The risk of pre-eclampsia was 26% in nulliparous patients versus 17% in parous subjects (relative risk and 95% confidence interval 1.5 [1.3-1.8]). CONCLUSIONS: The finding that second-trimester mean arterial pressure affects pre-eclampsia risk suggests that the pathophysiologic process of preeclampsia is initiated before that time.

Adult↗
PubMed1998

Loss of fimbrial adhesion with the addition of Vaccinum macrocarpon to the growth medium of P-fimbriated Escherichia coli.

PURPOSE: Vaccinium macrocarpon--the American cranberry--irreversibly inhibits the expression of P-fimbriae of E. coli. Further effects on the function and expression of P-fimbriae were studied by growing P-fimbriated E. coli in solid media laced with cranberry juice. METHODS: Cranberry concentrate at pH 7.0 was added to CFA medium to a final concentration of 25%. E. coli strains JR1 and DS17 were plated on this medium with a plain CFA control and incubated at 37C. Cultures were tested for ability to agglutinate P-receptor specific beads. Bacteria were washed in PBS and agglutination retested. Cultures were also replated on plain CFA agar and rechecked for their ability to agglutinate. Transmission electron micrographs were performed on positive control and test bacteria. RESULTS: For E. coli strain JR1, P-fimbrial agglutination was inhibited after the third plating. DS17 was fully inhibited after the second plating. Washing in PBS did not affect agglutination, but replating on CFA agar allowed agglutination to recur. Electron micrographic study of control populations confirmed fimbriae. Fully inhibited bacteria had a 100% reduction in expression of fimbriae. Additionally, inhibited bacteria showed cellular elongation. CONCLUSIONS: Cranberry juice irreversibly inhibits P-fimbriae. Electron micrographic evidence suggests that cranberry juice acts on the cell wall preventing proper attachment of the fimbrial subunits or as a genetic control preventing the expression of normal fimbrial subunits or both.

Bacterial Adhesion↗