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Biomedical subjects

W McIntosh

Publications and source records attributed to W McIntosh.

At least 19 recordsLinked to original sources

Aggressive behaviour in the high-secure forensic setting: the perceptions of patients.

Twenty-seven patients undergoing treatment in a high-secure forensic facility participated in focus group interviews to elicit their perceptions of (1) the factors leading to aggressive behaviour; and (2) strategies to reduce the risk of such behaviour. The focus group interviews were audiotaped, transcribed and analysed using content analysis. The participants identified that a combination of patient, staff and environmental factors contributed to violence in the study wards. The cause of aggressive behaviour centred around five major themes: the environment; empty days; staff interactions; medication issues; and patient-centred factors. Potential strategies identified by patients to reduce aggressive behaviour included: early intervention; the provision of meaningful activities to reduce boredom; separation of acutely disturbed patients; improved staff attitudes; implementation of effective justice procedures; and a patient advocate to mediate during times of conflict. Findings suggested that social and organizational factors need to be addressed to change the punitive subculture inherent in forensic psychiatric facilities, and to ensure a balance between security and effective therapy.

Aggression↗

Controlled-release of IGF-I and TGF-beta1 in a photopolymerizing hydrogel for cartilage tissue engineering.

Photopolymerizing hydrogel systems provide a method to encapsulate cells and implant materials in a minimally invasive manner. Controlled release of growth factors in the hydrogels may enhance the ability to engineer tissues. IGF-I and TGF-beta1 were loaded in PLGA microspheres using a double emulsion technique. 125 ng and 200 pg of active IGF-I and TGF-beta, respectively, as measured by ELISA, were released over 15 days. The growth factor containing microspheres were photoencapsulated with bovine articular chondrocytes in PEO-based hydrogels and incubated in vitro for two weeks. Statistically significant changes in glycosaminoglycan (GAG) production compared to control gels either without microspheres or with blank spheres were observed after a 14 day incubation with IGF-I and IGF-I/TGF-beta microspheres combined, with a maximum density of 8.41+/-2.5% wet weight GAG. Total collagen density was low and decreased with the IGF-I/TGF-beta microspheres after two weeks incubation, but otherwise remained unchanged in all other experimental groups. Cell content increased 10-fold to 0.18+/-0.056 x 10(6) cells/mg wet weight and extracellular matrix (ECM) staining by H&E increased in hydrogels with IGF-I/TGF-beta microspheres. In conclusion, photoencapsulation of microspheres in PEO-based hydrogels provides a method to deliver molecules such as growth factors in porous hydrogel systems.

Animals↗

Dissociative identity disorder and the nurse-patient relationship in the acute care setting: an action research study.

This paper presents the results of an action research study into the acute care experience of Dissociative Identity Disorder. The study, which was grounded in principles of critical social science, utilized focus group interviews and narrative construction. Nurses and patients are under-represented in all clinical evaluation and their voices need to be heard if services are to be truly collaborative. Findings of the study extend intrapsychic theories of trauma to emphasize the interpersonal relationship between nurse and person who can work together to facilitate recovery from trauma, make connections both intra and interpersonally and build resilience.

Acute Disease↗

Photoencapsulation of chondrocytes in poly(ethylene oxide)-based semi-interpenetrating networks.

A photopolymerizing hydrogel system provides an efficient method to encapsulate cells. The present work describes the in vitro analysis of bovine and ovine chondrocytes encapsulated in a poly(ethylene oxide)-dimethacrylate and poly(ethylene glycol) semi-interpenetrating network using a photopolymerization process. One day after encapsulation, (3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenyl-2H-tetrazolium bromide) (MTT) and light microscopy showed chondrocyte survival and a dispersed cell population composed of ovoid and elongated cells. Biochemical analysis demonstrated proteoglycan and collagen contents that increased over 2 weeks of static incubation. Cell content of the gels initially decreased and stabilized. Biomechanical analysis demonstrated the presence of a functional extracellular matrix with equilibrium moduli, dynamic stiffness, and streaming potentials that increased with time. These findings suggest the feasibility of photoencapsulation for tissue engineering and drug delivery purposes.

Animals↗

Transdermal photopolymerization for minimally invasive implantation.

Photopolymerizations are widely used in medicine to create polymer networks for use in applications such as bone restorations and coatings for artificial implants. These photopolymerizations occur by directly exposing materials to light in "open" environments such as the oral cavity or during invasive procedures such as surgery. We hypothesized that light, which penetrates tissue including skin, could cause a photopolymerization indirectly. Liquid materials then could be injected s.c. and solidified by exposing the exterior surface of the skin to light. To test this hypothesis, the penetration of UVA and visible light through skin was studied. Modeling predicted the feasibility of transdermal polymerization with only 2 min of light exposure required to photopolymerize an implant underneath human skin. To establish the validity of these modeling studies, transdermal photopolymerization first was applied to tissue engineering by using "injectable" cartilage as a model system. Polymer/chondrocyte constructs were injected s.c. and transdermally photopolymerized. Implants harvested at 2, 4, and 7 weeks demonstrated collagen and proteoglycan production and histology with tissue structure comparable to native neocartilage. To further examine this phenomenon and test the applicability of transdermal photopolymerization for drug release devices, albumin, a model protein, was released for 1 week from photopolymerized hydrogels. With further study, transdermal photpolymerization potentially could be used to create a variety of new, minimally invasive surgical procedures in applications ranging from plastic and orthopedic surgery to tissue engineering and drug delivery.

Animals↗

Transdermal photopolymerization of poly(ethylene oxide)-based injectable hydrogels for tissue-engineered cartilage.

Transdermal photopolymerization, a minimally invasive method for implantation, was used to subcutaneously place a mixture of polymer and isolated chondrocytes to regenerate cartilage tissue in vivo. Semi-interpenetrating networks of varying proportions of poly(ethylene oxide)-dimethacrylate and poly(ethylene oxide) and primary bovine articular chondrocytes were implanted in athymic mice. Four mice (12 implants) were harvested at 2, 4, and 7 weeks. Chondrocytes survived implantation and photopolymerization and formed neocartilage containing 1.5 to 2.9% wet weight collagen and 4 to 7% glycosaminoglycan. Thirty-five percent of the total collagen was type II collagen. Histologic analysis exhibited tissue structure resembling neocartilage, and safranin O staining demonstrated glycosaminoglycan distribution throughout the hydrogels. This study demonstrates the potential use of transdermal photopolymerization for minimally invasive subcutaneous implantation of hydrogels and chondrocytes for in vivo cartilage regeneration.

Animals↗

Acute diplopia and a solitary lung mass: a unique presentation of light-chain myeloma.

The patient described, a 51-year-old woman, had diplopia and cephalgia of two weeks' duration. On admission, the radiologic evaluation revealed a mass in the sphenoid sinus, multiple lesions in the calvarium and a solitary lung mass. Biopsy of the lung mass revealed an atypical plasmacytic infiltration. Laboratory findings confirmed the diagnosis of light-chain myeloma presenting with a pulmonary plasmacytoma and cranial nerve involvement.

Abducens Nerve↗

Barriers to assertive skills in nurses.

The role of nursing involves interaction with clients, peers and other health professionals. This role is enhanced when nurses have a good command of communication skills. An essential component of effective communication is the ability to behave assertively. Several studies have indicated that nurses lack assertiveness skills. This lack of assertiveness results in diminished effectiveness of communication and compromised patient care. The purpose of this study was to examine the barriers, identified in the literature, that prevent nurses from being assertive and to determine nurses' perceptions of how these barriers prevent them behaving assertively. The design of the study was a cross-sectional, correlational survey whereby the relationships between identified variables could be systematically investigated. Assertiveness was assessed using the Assertiveness Behaviour Inventory Tool (ABIT), and the Barriers to Assertive Skills in Nurses (BASIN) were assessed using an instrument developed for the study by the investigators. The validity and reliability testing of the BASIN instrument is discussed. The results indicated that the 152 nurses sampled considered themselves to have moderate to low assertiveness skills, and a significant negative correlation was found between the level of assertiveness and the perception of barriers inhibiting assertive behaviour. The study concluded that assertiveness training is needed for qualified nurses and that further testing of the ABIT and BASIN instruments will result in reliable measures for research and educational evaluation of nurses following assertiveness training.

Adult↗

Skeletal muscle beta 2-adrenoreceptors and the effect of adrenergic drugs on plasma potassium in perinephritis hypertension in rabbits.

1. It has been suggested that beta 2-adrenoreceptors in skeletal muscle regulate plasma potassium. The possibility that alterations in the function and/or density of these receptors occurs in perinephritis hypertension in rabbits was studied. 2. Intravenous infusion of adrenaline (0.2 micrograms kg-1 min-1) caused a fall in potassium while intravenous bolus injection of propranolol (0.75 mg kg-1) resulted in an increase in serum potassium which was of similar magnitude in both perinephritis hypertensive and sham-operated normotensive rabbits. 3. Binding studies with the radioligand [125I] cyanopindolol (ICYP) showed that there were no significant differences between the hypertensive and normotensive rabbits in the density (Bmax) or affinity (KD) of the skeletal muscle beta 2-adrenoreceptor. 4. The results suggest that function and density of skeletal muscle beta 2-adrenoreceptors are not altered in rabbits with perinephritis hypertension.

Animals↗

Effect of subdermal oestrogen and oestrogen/testosterone implants on calcium and phosphorus homeostasis after oophorectomy.

Various biochemical aspects of calcium metabolism were studied serially in 32 post-menopausal patients treated with subdermal implants of oestrogen, either alone or in combination with testosterone. Significant reductions in serum calcium, serum phosphate, the renal phosphate threshold (TmPO4) and the urinary calcium/creatinine ratio were observed for periods of up to 6 mth in both treatment groups as compared with baseline. The findings suggest that oestrogen replacement therapy by subdermal implant is effective in reversing the characteristic alterations in calcium metabolism which occur in the post-menopausal patient. The addition of testosterone does not appear to confer any additional benefit with respect to the parameters assessed.

Adult↗

Calcitonin and postmenopausal osteoporosis.

Fasting serum calcitonin levels were measured in 54 postmenopausal women who had for 10 years been taking part in a double blind trial to assess the effect of the synthetic oestrogen, mestranol, on postmenopausal bone loss. There were no differences in calcitonin levels between mestranol treated and placebo groups. Fifteen of the women were challenged with a calcium infusion to measure the secretory reserve of calcitonin. Oestrogen treatment did not increase the calcitonin response to calcium infusion. The three patients who exhibited the greatest responses were placebo treated. Bone density was measured by gamma-ray absorptiometry over the ten year period and the annual rate of change of bone density calculated. No correlation could be found between basal calcitonin level or calcitonin reserve and change in bone density. Our results indicate that postmenopausal osteoporosis is not caused by a deficiency of calcitonin and that the action of oestrogen therapy to prevent bone loss does not involve calcitonin.

Calcitonin↗

Malignant granular cell tumour (myoblastoma) of the vulva: report of a case and review of the literature.

A case of malignant granular cell tumour (myoblastoma) which metastasized from the vulva to the regional lymph nodes is presented. Electron microscopy of the metastases demonstrated the presence of numerous intra-cytoplasmic lysosomes, a feature characteristic of these neoplasms, and the neoplasm was shown to stain strongly for carcinoembryonic antigen (CEA) using the immunoperoxidase technique. Previous reports in the literature of malignant granular cell tumours are reviewed and discussed.

Adult↗

Amylase activity in human bile.

The mean amylase level in 42 human bile samples was 154 IU/l and there was no significant difference in the amylase activity of 32 paired serum and bile samples. Estimation of the amylase thermolability of bile showed it to be similar to that of serum. This suggests that the amylase activity in bile may have filtered through the liver from the hepatic circulation rather than refluxed from the pancreatic duct. The presence of amylase in human bile provides further evidence that the liver might have a role in the regulation of serum amylase.

Amylases↗

Serial serum amylase levels in patients with pancreatic pseudocysts.

The incidence of hyperamylasaemia in serial serum amylase levels from patients with pancreatic pseudocysts is not well documented in the literature. Accordingly serial amylase levels were estimated in 5 patients with proven pancreatic pseudocysts. The majority of the values were normal or only minimally elevated. In contrast the amylase thermolability was persistently elevated and appeared to be a more sensitive measurement than serum amylase activity for indicating the presence of pancreatic pseudocysts.

Amylases↗

Amylase creatinine clearance ratio after biliary surgery.

The amylase creatinine clearance ratio (ACCR) is considered to be a more sensitive index of acute pancreatitis than the serum amylase level. Serial ACCR estimations were undertaken in 25 patients undergoing an elective cholecystectomy. Using accepted criteria, 28% of these patients developed, in the postoperative period, biochemical evidence of pancreatic gland damage, although the serum amylase level remained normal. This raised ACCR was particularly noted in patients who had undergone an exploration of the common bile duct. The ACCR would appear to be a more sensitive index of pancreatic gland disruption secondary to biliary surgery than the serum amylase level.

Acute Disease↗

A cause of misleading serum amylase concentrations in acute pancreatitis.

The operative discovery of acute pancreatitis associated with gross hyperlipidaemia but a normal or high elevated serum amylase concentration has been described. We report a case of acute pancreatitis in which serial dilutions of serum resulted in a 338% rise in the serum amylase concentrations. The importance of appreciating this effect of hyperlipidaemia on the serum level measurements in patients with acute pancreatitis is re-emphasised.

Acute Disease↗