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Biomedical subjects

K Khan

Publications and source records attributed to K Khan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Development and validation of a questionnaire to evaluate the effectiveness of evidence-based practice teaching.

AIM: The aim of this study was to develop and validate a questionnaire to evaluate the effectiveness of evidence-based practice (EBP) teaching. METHODS: The 152 questionnaires completed by health care professionals with a range of EBP experience were used in this study. Cronbach's alpha for the knowledge and attitude questions indicated a satisfactory level of internal consistency (i.e. >0.60). RESULTS: The discriminative validity was evidenced by a statistically significant difference in the knowledge and attitude scores of 'novices' (i.e. little or no prior EBP education) compared with 'experts' (i.e. health care professionals and academics currently teaching EBP). Moderate to good (> or =0.4) sensitivity index scores were observed for both knowledge and attitude scores as the result of comparing individuals before and after an EBP intervention. CONCLUSIONS: The results of this validation study indicate that the developed questionnaire is a satisfactory tool with which to evaluate the effectiveness of EBP teaching interventions.

Education, Medical↗
PubMed2001

Radiological significance of building bricks in Pakistan.

Baked clay bricks samples were collected from both urban and rural areas of the North West Frontier Province of Pakistan and natural radioactivity due to 40K, 226Ra and 232Th has been measured in these samples. The specific absorbed dose rates due to natural radioactivity emanating from the walls, floors and ceilings of the typical model rooms made of these building bricks have been calculated applying the mesh size adaptive volume integral methodology. The occupancy factor, representing the weighted average of all the population in the country, was taken to be 0.3 in this study. The values of estimated annual effective dose rates for whole body were found to be 0.38 and 0.35 mSv.y(-1) for the two types of model rooms. These values are smaller than those predicted by UNSCEAR for normal background areas. Thus the building bricks analysed in this study do not pose any significant health problem to the population.

Background Radiation↗
PubMed2001

A double-blind, placebo-controlled crossover study investigating the effect of porcine secretin in children with autism.

OBJECTIVES: A recent patient series reported the incidental findings of improved social and language skills in 3 children with autistic spectrum disorders after the administration of secretin, a peptide hormone. However, a subsequent study did not find evidence for a drug effect. Parents are seeking treatment with secretin despite the absence of empirical investigations demonstrating amelioration in autism symptomology. In order to more precisely measure the effects of secretin, this study investigated the effect of a single intravenous dose of porcine secretin on 12 autistic children through a randomized, double-blind, placebo-controlled, crossover study. Children were assessed on objective language and on social, neuropsychological, and gastrointestinal measures to evaluate drug effects. The study was conducted over a 16-week trial. The results indicated that significant differences were not observed on the majority of the dependent variables. Statistically significant differences were observed on measures of positive affect and activity level following secretin infusion. In general, the autistic children did not demonstrate the improvements described in the initial retrospective report.

Affect↗
PubMed2001

Patient handling of a dry-powder inhaler in clinical practice.

BACKGROUND: Multi-dose dry-powder inhalers are perceived as being easier for patients to use than conventional pressurized aerosol inhalers; however, no study has determined whether patients handle such devices adequately and whether there is a need for patient education in this area. METHOD: We used trained observers to assess the handling of a specific multi-dose dry powder inhaler (Turbuhaler; AstraZeneca Canada; Mississauga, ON) by patients currently using the device for the management of their asthma. Fourteen discrete steps were scored independently by two observers simultaneously. Patients were divided into two groups for analysis: those who had received formal instruction in the use of the inhaler at The Asthma Centre and those who had received no formal instruction in the community. RESULTS: There was no significant difference between the formally trained groups and control groups in the percentage of handling steps performed correctly (79% vs 78%, respectively; p > 0.05). Fewer than 50% of patients in both groups demonstrated optimal breath-holding when using the device. CONCLUSION: Patient handling of Turbuhaler was generally good, with no evidence that a structured education intervention offered an advantage over the usual education incidental to the prescribing or dispensing process. The most common handling flaw, suboptimal breath-holding, is not specific to this device and is of uncertain clinical significance.

Adult↗
PubMed2000

Does childhood and adolescence provide a unique opportunity for exercise to strengthen the skeleton?

Osteoporosis is a major, and increasing, public health problem. In this review we examine the evidence that childhood physical activity is an important determinant of bone mineral in adult years, and as such, may help to prevent osteoporosis. Animal studies provide incontrovertible evidence that growing bone has a greater capacity to add new bone to the skeleton than does adult bone. Observational studies in children undertaking routine physical activity and cross-sectional athlete studies in young sportspeople both reveal that activity is positively associated with bone mineral density (BMD). Longitudinal studies in pre- and peripubertal gymnasts reveal BMD gains far in excess of those that can be achieved in adulthood. However, such studies permit only limited conclusions as they contain the potential for selection bias and can be confounded by other determinants of bone mineral (e.g. dietary and lifestyle factors). Thus, research comparing inter-individual playing-to-nonplaying arm differences in bone mineral (e.g., in racquet sports) have proven to be extremely useful. These studies suggest that the BMD differences are clearly greater when bone is subjected to mechanical loading prior to the end of puberty and longitudinal growth of the body (in women, before menarche) rather than after it. Tanner stage II and III appears to be the maturational stage when the association between exercise and BMD becomes manifest in most adolescents. Do conclusions drawn from athlete studies apply to the general population? Randomised intervention studies of physical activity and bone mineral accrual in normal children confirm that childhood activity is strongly associated with bone mineral accrual. Furthermore, some retired athlete studies and a detraining study suggest that adolescent bone gain may, at least partly, persist despite reduced adult physical activity. Mechanisms that may underlie the association between childhood physical activity and bone mineral accrual are outlined. Thus, it appears that physical activity during the most active period of maturity (with respect to longitudinal growth of the body) plays a vital role in optimising peak bone mass and that benefits may extend into adulthood.

Adult↗
PubMed2000

Peripherally administered antibodies against amyloid beta-peptide enter the central nervous system and reduce pathology in a mouse model of Alzheimer disease.

One hallmark of Alzheimer disease is the accumulation of amyloid beta-peptide in the brain and its deposition as plaques. Mice transgenic for an amyloid beta precursor protein (APP) mini-gene driven by a platelet-derived (PD) growth factor promoter (PDAPP mice), which overexpress one of the disease-linked mutant forms of the human amyloid precursor protein, show many of the pathological features of Alzheimer disease, including extensive deposition of extracellular amyloid plaques, astrocytosis and neuritic dystrophy. Active immunization of PDAPP mice with human amyloid beta-peptide reduces plaque burden and its associated pathologies. Several hypotheses have been proposed regarding the mechanism of this response. Here we report that peripheral administration of antibodies against amyloid beta-peptide, was sufficient to reduce amyloid burden. Despite their relatively modest serum levels, the passively administered antibodies were able to enter the central nervous system, decorate plaques and induce clearance of preexisting amyloid. When examined in an ex vivo assay with sections of PDAPP or Alzheimer disease brain tissue, antibodies against amyloid beta-peptide triggered microglial cells to clear plaques through Fc receptor-mediated phagocytosis and subsequent peptide degradation. These results indicate that antibodies can cross the blood-brain barrier to act directly in the central nervous system and should be considered as a therapeutic approach for the treatment of Alzheimer disease and other neurological disorders.

Alzheimer Disease↗
PubMed2000

Expression and processing of gastrin in pancreatic adenocarcinoma.

BACKGROUND: Gastrin is a trophic hormone and promotes growth of gastrointestinal and non-gastrointestinal cancers. Studies both in vitro and in vivo have suggested that pancreatic cancer cells not only have the ability to respond to circulating forms of gastrin but also to respond to the autocrine production of gastrin and its precursors. The aim of this study was to identify the expression of CCK-B/gastrin receptor, progastrin, glycine-extended gastrin and amidated gastrin in both normal pancreas and pancreatic adenocarcinoma. METHODS: Tissue sections from patients with normal pancreas (n = 10) and pancreatic cancer (n = 22) were assessed using immunohistochemical methods for CCK-B/gastrin receptor, progastrin, glycine-extended gastrin and amidated gastrin expression. RESULTS: Normal pancreas showed no expression of receptor or gastrin isoforms except for occasional cells in the islets. Definite expression of CCK-B/gastrin receptor, progastrin, glycine-extended gastrin and amidated gastrin was observed in 95, 91, 55 and 23 per cent of sections from patients with pancreatic cancer respectively. CONCLUSION: Pancreatic cancer cells express CCK-B/gastrin receptor and gastrin precursor forms in most patients. Expression of the gastrin precursor forms is probably related to autocrine production. New therapeutic strategies need to be developed for the management of pancreatic cancer. Targeting gastrin and its receptor may provide a novel treatment option.

Adenocarcinoma↗
PubMed2000

Outcome of reduction mammaplasty--a patients' perspective.

There have been several studies analysing the outcome of reduction mammaplasty in the literature. Our study is condition specific, with emphasis placed on the patients' subjective experience of treatment. Following a successful pilot study, data were obtained from 74 patients' charts and an anonymous postal questionnaire over a 1-year period. Sixty-six returned the questionnaire complete (89%). Overall satisfaction with the procedure was high (94%). The outcome of surgery with respect to breast size, shape, nipple position, sensation and scarring is documented. All patients expressed marked improvement regarding neck pain, back pain, submammary rash, breast pain and shoulder grooving. Other parameters including psychological wellbeing, quality of life, time on the waiting list, weight of tissue removed and complication rates are analysed. The findings of this study demonstrate overwhelming physical and psychological benefits from surgery. This supports the suggestion that reduction mammaplasty is not primarily cosmetic, producing significant improvement in symptoms.

Esthetics↗
PubMed2000

The role of physiotherapy in the prevention and treatment of osteoporosis.

Osteoporosis is an increasing public health problem that causes loss of life and reduced quality of life in sufferers. Strategies to improve bone density and reduce the likelihood of falls are important in the prevention of osteoporosis. Physiotherapists have a role to play in this condition through exercise prescription, therapeutic modalities, specific techniques and education. Appropriate treatment goals can be established following a thorough assessment of signs and symptoms, risk factors for osteoporosis and functional status. Levels of bone density measured from dual energy X-ray absorptiometry can help guide patient management. Since the aim is to maximize peak bone mass in children and adolescents, participation in a variety of high-impact activities should be encouraged. In the middle adult years, small increases in bone mass may be achieved by structured weight-training and weight-bearing exercise. In the older adult years, particularly if osteopenia or osteoporosis is present, the aim is to conserve bone mass, reduce the risk of falls, promote extended posture, reduce pain, and improve mobility and function.

Absorptiometry, Photon↗
PubMed2000

Prevention and reduction of AD-type pathology in PDAPP mice immunized with A beta 1-42.

In AD certain brain structures contain a pathological density of A beta protein deposited into plaques. The effect of genetic mutations found in early onset AD patients was an overproduction of A beta 42, strongly suggesting that overproduction of A beta 42 is associated with AD. We hypothesized that an immunological response to A beta 42 might alter its turnover and metabolism. Young PDAPP transgenic mice were immunized with A beta 1-42, which essentially prevented amyloid deposition; astrocytosis was dramatically reduced and there was reduction in A beta-induced inflammatory response as well. A beta 1-42 immunization also appeared to arrest the progression of amyloidosis in older PDAPP mice. A beta immunization appears to increase clearance of amyloid plaques, and may therefore be a novel and effective approach for the treatment of AD.

Alzheimer Disease↗
PubMed1999

Demonstration of new sites of expression of the CCK-B/gastrin receptor in pancreatic acinar AR42J cells using immunoelectron microscopy.

The CCK-B/gastrin receptor has been characterised in both normal and tumour tissues. Endocytosis of the CCK-B/gastrin receptor has recently been demonstrated and this has similarly been described for other peptide receptors. In addition, ligand and ligand-receptor translocation to the nucleus has been demonstrated for other peptides. The aim of this study was to identify the sites of expression of the CCK-B/gastrin receptor in the known CCK-B/gastrin receptor bearing pancreatic acinar AR42J cells. The specificity of the CCK-B/gastrin receptor antibody (alpha-CCKBR-Ser antibody) was demonstrated by inhibition ELISA studies, radioligand inhibition studies and immunofluorescence binding studies on AR42J cells. Western blotting and immunogold electron microscopy techniques were used to identify the receptor in AR42J cell preparations. The affinity purified alpha-CCKBR-Ser antibody was shown to be specific for the CCK-B/gastrin receptor. The receptor was expressed on the cell membrane, in the cytoplasm and within the nucleus. Isoforms of the receptor protein identified in extra-nuclear and nuclear extracts ranged in molecular weight from 58 to 66 kDa. We conclude that the CCK-B/gastrin receptor is not only expressed on the cell membrane, but also in the cytoplasm and nucleus of AR42J pancreatic acinar cells.

Animals↗
PubMed1999

Immunization with amyloid-beta attenuates Alzheimer-disease-like pathology in the PDAPP mouse.

Amyloid-beta peptide (Abeta) seems to have a central role in the neuropathology of Alzheimer's disease (AD). Familial forms of the disease have been linked to mutations in the amyloid precursor protein (APP) and the presenilin genes. Disease-linked mutations in these genes result in increased production of the 42-amino-acid form of the peptide (Abeta42), which is the predominant form found in the amyloid plaques of Alzheimer's disease. The PDAPP transgenic mouse, which overexpresses mutant human APP (in which the amino acid at position 717 is phenylalanine instead of the normal valine), progressively develops many of the neuropathological hallmarks of Alzheimer's disease in an age- and brain-region-dependent manner. In the present study, transgenic animals were immunized with Abeta42, either before the onset of AD-type neuropathologies (at 6 weeks of age) or at an older age (11 months), when amyloid-beta deposition and several of the subsequent neuropathological changes were well established. We report that immunization of the young animals essentially prevented the development of beta-amyloid-plaque formation, neuritic dystrophy and astrogliosis. Treatment of the older animals also markedly reduced the extent and progression of these AD-like neuropathologies. Our results raise the possibility that immunization with amyloid-beta may be effective in preventing and treating Alzheimer's disease.

Alzheimer Disease↗