Biomedical subjects

M Stewart

Publications and source records attributed to M Stewart.

At least 397 records · Page 22Linked to original sources

PubMed1986

A hospital-based mental health court.

Deinstitutionalized chronically mentally ill patients face the prospect of homelessness, insufficient community services, and the possibility of criminalization. Further, many communities do not have a mechanism for recognizing the special problems many of the chronically mentally ill have when they enter the legal system. The following is a description of a hospital-based mental health court, a nontraditional, highly effective program intended to identify chronically mentally ill persons in the community, as well as recognize and correct inadequacy in services available to the deinstitutionalized.

Chronic Disease↗

PubMed1986

AN ultrastructural study of cross-bridge arrangement in the frog thigh muscle thick filament.

We have developed thick filament isolation methods that preserve the relaxed cross-bridge order of frog thick filaments such that the filaments can be analyzed by the convergent techniques of electron microscopy, optical diffraction, and computer image analysis. Images of the filaments shadowed by using either unidirectional shadowing or rotary shadowing show a series of subunits arranged along a series of right-handed near-helical strands that occur every 43 nm axially along the filament arms. Optical filtrations of images of these shadowed filaments show 4-5 subunits per half-turn of the strands, consistent with a three-stranded arrangement of the cross-bridges, thus supporting our earlier results from negative staining and computer-image analysis. The optical diffraction patterns of the shadowed filaments show a departure from the pattern expected for helical symmetry consistent with the presence of cylindrical symmetry and a departure of the cross-bridges from helical symmetry. We also describe a modified negative staining procedure that gives improved delineation of the cross-bridge arrangement. From analysis of micrographs of these negatively stained filament tilted about their long axes, we have computed a preliminary three-dimensional reconstruction of the filament that clearly confirms the three-stranded arrangement of the myosin heads.

Actin Cytoskeleton↗

PubMed1986

The patient-centred clinical method. 2. Definition and application.

In this article, the patient-centred clinical method is described in operational terms. Definitions are given for the patient's expectations, feelings and fears. The physician behaviours described are: facilitations, acknowledgements, cut-offs and returns. Using the definitions, a method was devised for scoring video-taped interviews for the degree of 'patient-centredness'. The method proved to have good inter-observer reliability.

Attitude to Health↗

PubMed1986

The patient-centred clinical method. 3. Changes in residents' performance over two months of training.

A method for assessing the patient-centred approach was used to identify changes taking place in the interviewing behaviour of 13 residents during two months in a teaching practice. The descriptive study confirmed the prediction that the residents' approach would become more patient-centred. A statistically significant change from August to October was found in the number of facilitating behaviours shown by residents (P less than 0.05) and there was a change in the number of fears expressed by patients (P less than 0.10). Increases in the number of expectations, feelings and prompts were noted but were not significant. The frequency with which residents cut off patients' expressions increased on the whole, although not significantly. The findings suggest that while these residents had succeeded in increasing their facilitating behaviours over two months (one-sixth of their family medicine experience) they had not yet found ways of responding to the many problems elicited.

Family Practice↗

PubMed1986

Two patterns in the Aeromonas salmonicida A-layer may reflect a structural transformation that alters permeability.

Electron micrographs of negatively stained regular surface layers (A-layers) of Aeromonas salmonicida showed two square patterns having p4 symmetry. Computer image processing demonstrated that, at a resolution of 2.3 nm, both square arrays were composed of two different morphological units arranged alternatively to give a face-centered lattice in which the four nearest neighbors of each unit were the other type of unit. The lattice constant was slightly but significantly different in the two patterns, and the orientation of one of the two morphological units changed by about 20 degrees between patterns. These patterns were probably not derived from different strains present in the preparation, since both were seen in material that appeared to come from a single layer. This and the difference in lattice constant made it unlikely that they represented different sides of the A-layer. However, it is possible that the two patterns may reflect a structural transformation of the layer. In this respect, it is interesting that the rotation of one morphological subunit changed the size of the gaps between units in the layer. This raised the possibility that the transformation could be related to a change in permeability of the A-layer, possibly analogous to that proposed for gap junctions in eucaryotic cells.

Aeromonas↗

PubMed1986

Identical twins discordant for presenile dementia of the Alzheimer type.

In genetically proven identical female twins, discordant for presenile dementia of the Alzheimer type, the affected twin began to dement at the age of 49, and died 15 years later; the diagnosis was confirmed at post-mortem. The surviving twin remains clinically unaffected 20 years after the onset of dementia in her sister. Environmental aetiological factors are postulated to account for this discordance.

Alzheimer Disease↗

PubMed1986

Perinatal autopsy: its clinical value.

The clinical value of the routine autopsy was studied in 172 sequential cases of perinatal deaths. Of these cases 139 (81%) were autopsied including 52 fetal deaths and 87 neonatal deaths. The clinically assigned cause of death was compared with the cause of death as identified by the autopsy. In 26% (nine fetal and 27 neonatal deaths) the autopsy was the sole means of establishing the cause of death. A need for specific genetic counseling or evaluation was identified in 62 of the 139 perinatal deaths. In 30 (48%) cases the autopsy was the sole source of information highlighting this need. The autopsy is an important clinical tool providing useful information to the perinatal clinician. Besides providing specific causes of death, it can correct clinical impressions and identify genetic factors that require further assessment and counseling.

Autopsy↗

PubMed1986

Urinary diversion and bowel cancer.

A retrospective survey of 278 patients who underwent urinary diversion for benign disease has revealed an excess risk factor for cancer at the ureterocolic anastomosis of approximately 100 fold. No malignancies were detected in isolated ileal or colon conduits, although recently a few such cases have been reported. Coupling this experience with a review of the literature, it would appear that the tumour is of colonic origin, adenoma and adenocarcinoma occurring at, or close to, the ureteric implant into the colon after a long latency of approximately 25 years, often in young patients. Nitrate reducing bacteria and N.nitroso compounds have been demonstrated in rectal urines of patients with ureterocolic anastomoses and also in some isolated loop urines. In fact, N.nitrosation and, possibly, carcinogenesis appears to depend not so much upon the kind of diversion, but rather the presence or absence of a mixed bacterial flora in the urine.

Adult↗

PubMed1985

Crystalline order to high resolution in the sheath of Methanospirillum hungatei: a cross-beta structure.

Electron microscopy and electron diffraction indicate that the outer sheath of the cell wall of the archaebacterium Methanospirillum hungatei contains a two-dimensional crystalline lattice having, at least to low resolution, p2 symmetry in projection with a = 5.66 nm, b = 2.81 nm and gamma = 85.6 degrees. At a resolution of 2 nm, the unit cell contains two lobes, whereas high-angle electron diffraction shows the presence of a substantial quantity of beta structure, with the 0.47 nm spacing (between polypeptide chains within a sheet) oriented circumferentially. The sheath is unusual when compared to other regular surface arrays found on bacteria in that it is a compact structure with small subunits. It may have a structural role analogous to barrel hoops since it tends to fragment perpendicular to its axis to give rings or hoops.

Archaea↗

PubMed1985

Conservative management of post-traumatic parotid fistulae and sialoceles: a prospective study.

A prospective study of 14 consecutive patients with parotid injuries treated over a 4-month period, is presented. Three patients underwent emergency duct repair and 11 patients, presenting with delayed fistulae or subcutaneous collections of saliva (sialoceles), were treated conservatively with uniform success. Glandular injury closed within an average of 5 days of treatment and ductal leaks within approximately 14 days.

Adult↗

PubMed1985

Comparison of serum and cerebrospinal fluid levels of methotrexate in man during high-dose chemotherapy for aggressive non-Hodgkin's lymphoma.

The relationship between plasma and cerebrospinal fluid levels of methotrexate was studied in five patients, four with aggressive non-Hodgkin's lymphoma and one with mixed epithelial mesothelial tumour, who were treated with high-dose methotrexate (1.5 g/m2) as part of combination chemotherapy. Cerebrospinal fluid was sampled for 24 h via a permanent indwelling lumbar catheter. No complications were observed with this technique. In two patients with central nervous system involvement adequate "cytotoxic" levels (greater than 10(-6) M) were obtained for greater than 12 h. The remaining three patients, with no direct evidence of central nervous system involvement, never attained adequate cytotoxic methotrexate levels in the cerebrospinal fluid. Serum levels were therapeutic in all patients. These results suggest that patients with central nervous system tumour involvement may receive adequate doses of methotrexate in the cerebrospinal fluid. Patients with occult central nervous system tumour involvement may not attain adequate cerebrospinal fluid levels. A 24-h serum methotrexate level of greater than 10(-5) M may indicate that patients have achieved therapeutic cerebrospinal fluid levels of methotrexate. Cranial irradiation following chemotherapy is still recommended in this tumour group until adequate cytotoxic levels of methotrexate can be obtained in all patients for prolonged periods.

Adult↗

PubMed1985

Necrotizing enterocolitis in pulmonary atresia with intact ventricular septum.

Necrotizing enterocolitis (NEC) occurred in 2 neonates with pulmonary atresia and intact ventricular septum. Both infants underwent open heart surgery for the insertion of a right ventricular outflow tract patch under profound hypothermia, surface cooling and a fibrillating heart, without circulatory arrest. In both patients the development of NEC preceded both the cardiac catheterization study and open heart surgery. Urgent repair of the cardiac lesion was undertaken in an attempt at improving the critical bowel wall ischemia. Postoperatively, exacerbation of the NEC reached an advanced stage rapidly leading to the death of the patients. Recommendations regarding the management of future cases exhibiting this potentially lethal combination of disease are presented.

Adult↗

PubMed1985

Subunit structure of paired helical filaments in Alzheimer's disease.

The neurofibrillary tangles that occur in the brain in cases of senile dementia of the Alzheimer type contain a distinctive type of filament, the paired helical filament (PHF). We have developed a method for isolating the tangles postmortem in sufficient yield for structural study of PHFs by electron microscopy of negatively stained and shadowed preparations. This material shows the characteristic helical structure seen in sectioned embedded material. In addition, two striking fragmentation patterns are observed. (a) Some filaments show sharp transverse breaks at apparently random positions along the filament. (b) In a few PHFs one strand is missing for a variable length, whereas the other appears to maintain its structural integrity. The shadowed specimens show the PHF to be wound in a left-handed manner. These observations indicate that the PHF consists of subunits of very limited axial extent arranged along two left-handed helical strands. The visualization of the substructure within the PHFs is rather variable and a model building approach has therefore been adopted, which has allowed the main features seen in the images to be interpreted. The subunit appears to have at least two domains in a radial direction and an axial extent of less than 5 nm. The whole structure can best be described as a twisted ribbon and indeed alkali treatment does untwist PHFs to give flat ribbons. The nature of the proposed model makes it most unlikely that the PHF is formed by a simple collapse of normal cytoskeletal elements, such as neurofilaments.

Aged↗

PubMed1985

Electron microscopic and optical diffraction analysis of the structure of scorpion muscle thick filaments.

We rapidly and gently isolated thick filaments from scorpion tail muscle by a modification of the technique previously described for isolating Limulus thick filaments. Images of negatively stained filaments appeared to be highly periodic, with a well-preserved myosin cross-bridge array. Optical diffraction patterns of the electron micrograph images were detailed and similar to optical diffraction patterns from Limulus and tarantula thick filaments. Analysis of the optical diffraction patterns and computed Fourier transforms, together with the appearance of the filaments in the micrographs, suggested a model for the filaments in which the myosin cross-bridges were arranged on four helical strands with 12 cross-bridges per turn of each strand, thus giving the observed repeat every third cross-bridge level. Comparison of the scorpion thick filaments with those isolated from the closely related chelicerate arthropods, Limulus and tarantula, revealed that they were remarkably similar in appearance and helical symmetry but different in diameter.

Animals↗

PubMed1985

Three-dimensional reconstruction of thick filaments from Limulus and scorpion muscle.

We have produced three dimensional reconstructions, at a nominal resolution of 5 nm, of thick filaments from scorpion and Limulus skeletal muscle, both of which have a right-handed four-stranded helical arrangement of projecting subunits. In both reconstructions there was a distinct division of density within projecting subunits consistent with the presence of two myosin heads. Individual myosin heads appeared to be curved, with approximate dimensions of 16 X 5 X 5 nm and seemed more massive at one end. Our reconstructions were consistent with the two heads in a projecting subunit being arranged either antiparallel or parallel to each other and directed away from the bare zone. Although we cannot exclude the second of these interpretations, we favor the first as being more consistent with both filament models and also because it would enable easy phosphorylation of light chains. The antiparallel interpretation requires that the two heads within a subunit derive from different myosin molecules. In either interpretation, the two heads have different orientations relative to the thick filament shaft.

Animals↗

PubMed1985

Alterations in plasma-, monocyte-, and lymphocyte-associated fibronectin during cardiopulmonary bypass surgery.

The changes in plasma fibronectin and IgG, and monocyte- and lymphocyte-associated fibronectin were studied in patients undergoing elective cardiopulmonary bypass surgery. A significant fall (P = less than 0.0005) in plasma fibronectin occurred during bypass, resulting largely from hemodilution as assessed by IgG concentrations, but also related to consumption of fibronectin. Plasma levels were still reduced 48 hours following the operative procedure, despite variable amounts of blood components infused in the immediate post-bypass period. Monocyte-associated fibronectin increased significantly (P = less than 0.05) during bypass, and lymphocyte-associated fibronectin levels decreased. Our studies confirm a reduction in circulating fibronectin in cardiac surgery, with accompanying fall in lymphocyte-associated levels presumed to reflect nonspecific adsorption. In contrast, the increased binding to monocytes may be an important functional aspect requiring further investigation, together with assessment of monocyte-macrophage function, before empiric use of cryoprecipitate therapy in these patients is recommended.

Adult↗

PubMed1985

A graduate programme for academic family physicians.

The paper describes a graduate studies programme designed to prepare outstanding family physicians for academic leadership and reports an evaluation of the programme. The programme aims to produce academic family physicians who exhibit certain qualities: outstanding clinical skills, professional interest in the organization and transmission of knowledge, and a scholarly approach through research and skills of leadership. The course includes clinical and teaching practice, formal course work and a scholarly thesis; the emphasis is on teaching and learning, theoretical foundations of family medicine, whole person medicine, research design and techniques, ethical decision making, and administration of organizations. A survey of the first 30 graduates of the programme indicated that the majority did more clinical teaching, small group teaching, research, writing and administration than before the course. The graduates' opinions of the programme indicated the extent to which the programme goals have been met; to provide a coherent learning experience integrating the art, science and technology of the discipline of family medicine.

Canada↗

PubMed1985

Thirty-five-day modified red cells and 7-day stored platelet concentrates from triple bags of identical PVC formulation.

There is continuous need for blood components with long shelf life. To this end the 'circle' triple pack has been modified to provide 35-day red cell and 7-day platelet concentrates, in PVC bags of identical formulation and 0.4 mm thick. The plasticizer is a mixture of DEHP and TOTM (CLX Mark II). The primary pack contains 63 ml of CP 277.5 mM glucose. The third pack contains 100 ml of citric acid 2 mM, trisodium citrate 20 mM, NaH2PO4 20 mM, NaCl 123 mM, glucose 40 mM, and adenine 1.26 mM. Plasma is adenine-free. With these modifications both hard- and soft-spun red cells gave satisfactory biochemical and autologous survival indices up to 35 days of storage, the haematocrit not exceeding 60%. Platelet concentrates were acceptable at 7 days of shelf-life.

Adenosine Triphosphate↗