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Biomedical subjects

P Winchester

Publications and source records attributed to P Winchester.

At least 19 recordsLinked to original sources

Cyclone mitigation, resource allocation and post-disaster reconstruction in south India: lessons from two decades of research.

This paper opens with a history of development and disaster-prevention strategies in a cyclone-prone area of the east coast of India and traces the evolution in the area of British and Indian governments' programmes and policy over a century. Research over the last 20 years has shown, however, that the programmes and policies have failed to balance economic growth with safety. Resources intended for the benefit of all have been diverted by alliances of powerful people to a small minority, and recent developments have reduced the physical protection of the area. The result is that increasing numbers of people are vulnerable to the effects of cyclones and floods. The findings suggest that the best way to reduce vulnerability is to improve the socio-economic standing of the most vulnerable and for this to happen these people must have an assured income based on assets that will enable them to acquire social and economic credit-worthiness within the local economy. This paper presents evidence that suggests that non-governmental organisation (NGO)-supported co-operatives are the best way to achieve this through self-help and self-employment schemes. It also suggests that NGOs should be encouraged to take up environmentally and ecologically beneficial activities involving the poorest groups in the communities, in this way combining sustained self-employment with environmental protection.

Community Participation↗

Activation of the insular cortex during dynamic exercise in humans.

1. The insular cortex has been implicated as a region of cortical cardiovascular control, yet its role during exercise remains undefined. The purpose of the present investigation was to determine whether the insular cortex was activated during volitional dynamic exercise and to evaluate further its role as a site for regulation of autonomic activity. 2. Eight subjects were studied during voluntary active cycling and passively induced cycling. Additionally, four of the subjects underwent passive movement combined with electrical stimulation of the legs. 3. Increases in regional cerebral blood flow (rCBF) distribution were determined for each individual using single-photon emission-computed tomography (SPECT) co-registered with magnetic resonance (MR) images to define exact anatomical sites of cerebral activation during each condition. 4. The rCBF significantly increased in the left insula during active, but not passive cycling. There were no significant changes in rCBF for the right insula. Also, the magnitude of rCBF increase for leg primary motor areas was significantly greater for both active cycling and passive cycling combined with electrical stimulation compared with passive cycling alone. 5. These findings provide the first evidence of insular activation during dynamic exercise in humans, suggesting that the left insular cortex may serve as a site for cortical regulation of cardiac autonomic (parasympathetic) activity. Additionally, findings during passive cycling with electrical stimulation support the role of leg muscle afferent input towards the full activation of leg motor areas.

Adult↗

Computed radiography in neonatal and pediatric intensive care units: a comparison of 2.5 K x 2 K soft-copy images vs digital hard-copy film.

OBJECTIVE: The goal of the study was to determine whether soft-copy images on high-resolution monitors (2.5 K x 2 K) are suitable for primary interpretation of images from pediatric and neonatal intensive care units. The hypotheses were that hard and soft images yield similar diagnostic information, and that both residents and faculty radiologists can use monitors effectively. Previous reports have produced conflicting results; the need for larger sample sizes has been emphasized. MATERIALS AND METHODS: One thousand one hundred and four images produced by computed radiography using the Kodak Ectascan Imagelink system were prospectively analyzed by two pediatric radiologists, one reading hard copy and the other soft copy of the same images. Bias was controlled by equal distribution of modalities between observers and by daily alternation of modality. Hard- and soft-copy observations of presence or absence of nine specific tubes and nine specific diagnostic findings were compared. Interobserver differences between pediatric radiologists and radiology residents were studied on additional images. The kappa statistic was used to evaluate the level of agreement for all observations. RESULTS: There was excellent agreement between hard and soft copy interpretation for each tube and diagnostic finding (kappa values 0.93-1.0) and excellent interobserver agreement between two pediatric radiologists (kappa values 0.84-1.0). The level of agreement between radiology residents and pediatric radiologist was excellent for the most objective findings. All results were statistically significant (p < 0.001). CONCLUSION: High resolution soft-copy images are suitable for primary interpretation in patients in pediatric and neonatal intensive care units.

Child↗

In vitro model to evaluate the relative efficacy of catheter-directed thrombolytic strategies.

RATIONALE AND OBJECTIVES: Catheter-directed thrombolytic therapy has become an accepted treatment for many vascular occlusions. However, the relative rates of lysis of the different methods of drug administration have not been quantified. We developed an in vitro model to simulate and quantify local lytic therapy of a thrombotic vascular occlusion and tested it by evaluating three catheter-directed lytic strategies. METHODS: Seven-centimeter-long segments of 125I-fibrinogen-labeled thrombus made from recently expired human blood from a blood bank were formed in plastic tubes and were placed in a flowing stream of saline. Using multisidehole catheters, the clots were "treated" with intrathrombic saline or urokinase administered by drip infusion or forced injection using identical total doses of drug and volumes of fluid. Using endhole catheters, saline or urokinase was drip infused into the leading edge of the thrombus using the same protocol. A collimated scintillation detector was used to quantify the amount of activity remaining in the thrombus during each experiment, and the resultant time-activity curves for the different trials were compared. RESULTS: Forced-injection administration of urokinase using a multisidehole catheter produced the fastest lysis, resulting in a half-life of 42 min. The other infusion methods were slower, with half-lives of 153 min for multisidehole urokinase drip infusion, 365 min for endhole urokinase drip infusion, and more than 1,000 min for multisidehole catheter forced injection of saline and multisidehole and endhole saline drip infusion. The differences among these groups were reproducible and statistically significant. CONCLUSION: Results suggest that a simple and inexpensive in vitro model simulating lysis of a vascular occlusion can produce reproducible quantitative data. The data demonstrate that forced injection of lytic agents with a multisidehole catheter enhances the rate of thrombolysis and that the enhancement is not primarily attributable to the mechanical effect of this mode of administration.

Catheterization, Peripheral↗

Physiologic costs of reciprocal gait in FES assisted walking.

This study reports the velocity and physiologic cost index (PCI) of ambulation using a functional electrical stimulation (FES) system for ambulation in paraplegic spinal cord injured subjects. Using established techniques, average velocity and heart rate (HR) were measured on five subjects trained with the Parastep system. PCI was reported for the four subjects who achieved a steady state during ambulation with the Parastep system. It was found that walking performance varied greatly between subjects, and was correlated to frequency of use of the system. Velocity of walking with the Parastep system ranged from 4.6 to 24.3 m/min. In the four subjects where steady state was achieved, PCI ranged from 2.30 to 6.26 beats/m. The average walking speed and PCI were similar to the values reported using alternative mechanical or hybrid systems available to the spinal cord injured for restoration of upright locomotion.

Adult↗

Primary skeletal non-Hodgkin's lymphoma in the pediatric age group.

The authors discuss rare primary skeletal non-Hodgkin's lymphoma in 16 patients treated from 1973 to 1989. The symptoms of these patients related to bone lesions in 95% of the cases. These bone lesions were monostotic or polyostotic, with or without regional and distant metastases. The locations of these lesions were long bones in 13 patients, pelvic bones in seven patients, and skull and vertebral bodies in two patients. The anatomical locations of these lesions in the bones were diaphysis alone in one patient, epiphysis in two patients, metaphysis in three patients, and a combination of diaphyseal, epiphyseal, and metaphyseal lesions in seven patients. Extraskeletal involvement was present in nine patients; extraskeletal sites included regional or distant lymph node involvement in seven cases, the mediastinum in two, lung nodules in two patients, the skin and subcutaneous regions in four patients; bone marrow in three patients, and peripheral nervous system (PNS) in one patient. Two patients had stage I disease, three had stage II disease, eight had stage III disease, and three had stage IV disease. The majority of patients had large noncleaved cell diffuse lymphomas or DHL by Rappaport classification. All patients were treated with the LSA2-L2 protocol; six patients received radiation therapy to the affected bone, and ten patients received no radiation therapy. Three patients failed on treatment within the first 4 months of therapy. Two patients developed a second tumor, one in the radiation therapy field and the other in a patient who received no radiation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Enteric fistula formation secondary to necrotizing enterocolitis.

We report two cases of enterocolonic fistula formation following necrotizing enterocolitis, and a review of the six previously published cases. Ischemic mechanism is the most likely cause. The fistulas were diagnosed by upper gastrointestinal series and contrast enema.

Colonic Diseases↗

A xanthogranulomatous histiocytosis in a child presenting with short stature.

We evaluated a 7-year-old boy presenting with a neck mass that was diagnosed as juvenile xanthogranuloma on excisional biopsy. Despite this diagnosis, an exhaustive evaluation was undertaken because of marked short stature. Examination revealed growth hormone deficiency and diabetes insipidus, as well as widespread lesions in the head, mediastinum, retroperitoneum, skeleton, and elsewhere. Biopsies of the lesions in the mediastinum and right tibia suggested a diagnosis of xanthoma disseminatum with bony involvement, suggesting the Erdheim-Chester variant of xanthogranulomatous histiocytosis, previously reported only in adults. The diagnosis is contrasted to the more common clinical entities of juvenile xanthogranuloma and the Langerhans' cell histiocytoses. This case illustrates the gravity with which otherwise unexplained short stature should be considered.

Child↗

Deferoxamine-induced bone dysplasia in patients with thalassemia major.

Metaphyseal irregularity and abnormal vertebral bodies resembling a bone dysplasia were seen in two of five children with thalassemia major who were begun on a regimen of hypertransfusion and chelation with deferoxamine before the age of 3 years. Similar changes were not seen in 22 other children in whom chelation was started after the age of 3. Whether the dysplastic bone growth was related to drug dose or age of onset of chelation could not be determined, as deferoxamine dosages differed in the two groups. Findings on radiographs included flattening of the thoracic and lumbar vertebral bodies, circumferential metaphyseal osseous defects, sharp zones of provisional calcification, and widened growth plates. Healing was noted in one of the patients after the dose of deferoxamine was decreased. Zinc levels in both affected patients did not differ from those in the 25 other chelated patients.

Adolescent↗

Calcified neonatal renal vein thrombosis demonstration by CT and US.

Two cases of calcified renal vein thrombosis (RVT) were diagnosed, incidentally, within the first weeks of life. The CT images present the virtually diagnostic branching pattern of calcification that has been previously noted on pathology specimen radiographs. The CT and US images show peripheral renal vein, central renal vein and inferior vena cava calcification conforming to the two theoretical origins of intravascular calcification. The patients had normal laboratory results and no symptoms related to renal vein or inferior vena cava thrombi.

Calcinosis↗

Imaging of prenatally detected intra-abdominal extralobar pulmonary sequestration.

Intra-abdominal extralobar pulmonary sequestration is a rare congenital anomaly which may present as an abdominal mass. We describe a case of intra-abdominal extralobar pulmonary sequestration detected prenatally as a left suprarenal mass. The ultrasound, computed tomography and magnetic resonance imaging findings are illustrated and correlated with the pathologic findings.

Adult↗

Neonatal necrotizing enterocolitis: air in Morison pouch.

Six newborn infants with necrotizing enterocolitis (NEC) were noted to have air confined to Morison pouch as an early sign of pneumoperitoneum. Air in Morison pouch appears as a triangular lucency in the right upper quadrant. Extraluminal air in this location is easily mistaken for air within a loop of bowel if its characteristic appearance is not specifically sought. Review of the literature revealed no reported cases of NEC in which air in Morison pouch was mentioned. The authors' observation of six patients suggests that air in Morison pouch may be more common than previously recognized. Air in Morison pouch has the same significance as more obvious signs of pneumoperitoneum, and its detection is an indication for surgery.

Colonic Diseases↗

Safety of metallic surgical clips in patients undergoing high-field-strength magnetic resonance imaging.

Use of metallic clips with ferromagnetic properties in patients undergoing a large variety of surgical procedures, and in particular, in coronary artery and other vascular reconstructions, has become increasingly popular. The safety of these commonly used surgical clips when subjected to high-intensity diagnostic magnetic resonance imaging fields is still debated. Commonly used hemostatic metallic clips manufactured by the Weck and US Surgical Corporations were tested in an in vitro system to assess their safety with regard to migration and displacement. The two tested hemostatic metallic clips proved safe and did not migrate or become dislodged when they underwent magnetic resonance imaging scans. This is in direct contrast to multiple cerebral aneurysm clips, also tested, which have highly ferromagnetic properties and were previously shown to migrate with disastrous results in patients undergoing diagnostic magnetic resonance imaging scans. This study supports the continued widespread use of small metallic hemostatic clips in the myriad of procedures in which they are presently used and illustrates the need for methods of evaluating such devices before they are clinically implanted.

Electromagnetic Fields↗

Adrenal hemorrhage and renal vein thrombosis in the newborn: MR imaging.

Three newborn infants with flank masses underwent magnetic resonance (MR) imaging after ultrasound (US) indicated adrenal hemorrhage and/or renal vein and inferior vena cava thrombosis. MR imaging was valuable in defining the hemorrhagic nature of echogenic and hypoechoic suprarenal masses and in delineating thrombi within the renal veins and inferior vena cava. Two infants with renal parenchymal damage had abnormal radionuclide scans and abnormal corticomedullary distinction on MR images. The major role of MR imaging may be in the early course of these conditions, when added diagnostic specificity is likely to affect patient management. In most instances, size of hemorrhage and intravenous clots, as well as renal size, may be accurately followed with US, while radionuclide scanning remains necessary for evaluation of renal functional impairment.

Adrenal Gland Diseases↗