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Biomedical subjects

P Mathew

Publications and source records attributed to P Mathew.

At least 73 records · Page 4Linked to original sources
PubMed1995

Neurosurgical management of cerebellar haematoma and infarct.

The clinical features, treatment, and outcome were reviewed for 48 patients with a haematoma and 71 patients with an infarct in the posterior fossa in order to develop a rational plan of management. Clinical features alone were insufficient to make a diagnosis in about half of the series. Patients with a haematoma were referred more quickly to the neurosurgical unit, were more often in coma, and more often had CT evidence of brain stem compression and acute hydrocephalus. Ultimately, 75% of the patients with a haematoma required an operation. By contrast, most patients with an infarct were managed successfully conservatively. Early surgical management in both cerebellar haemorrhage and infarct (either external ventricular drainage or evacuation of the lesion), associated with early presentation and CT signs of brain stem compression and acute hydrocephalus, led to a good outcome in most patients. Of the patients with cerebellar haematoma initially treated by external drainage, over half subsequently required craniectomy and evacuation of the lesion; but, in some cases, this failed to reverse the deterioration. In patients with a cerebellar infarct, external drainage was more often successful. The guidelines, findings, and recommendations for future management of patients with posterior fossa stroke are discussed.

Adult↗
PubMed1995

Localization of the murine homolog of the anaplastic lymphoma kinase (AlK) gene on mouse chromosome 17.

The murine homolog of the human anaplastic lymphoma kinase gene, which encodes a membrane-spanning receptor tyrosine kinase in the insulin receptor kinase subfamily, was assigned to mouse Chromosome 17 by interspecific backcross analysis. This assignment further confirms the homology between a portion of the distal Chromosome 17 and the short arm of human chromosome 2 and extends this region in the mouse by an additional 3 cM.

Anaplastic Lymphoma Kinase↗
PubMed1994

Focal brain injury: histological evidence of delayed inflammatory response in a new rodent model of focal cortical injury.

Cortical contusions are one of the most common characteristics in head injury and are regarded by many as the hallmark of significant injury. No experimental study has clarified the roles of mechanical forces, haemorrhage and ischaemia in the process of progressive acute brain damage and later neurobehavioural dysfunction. We have devised a new, simple reproducible rodent model of focal cortical injury which employs a 'pure' mechanical/physical force applied through the intact dura. Using this model we have investigated the time course and pattern of changes in neurons, glia and microvasculature. With the exception of haemorrhage, this model closely reproduces the light- and electron microscopy features of human contusion. In the absence of perivascular haemorrhage we have demonstrated delayed perivascular protein leakage and polymorphonuclear-leukocyte infiltration of the damaged cortex. We postulate that a component of the delayed blood brain barrier breakdown demonstrated in human focal head injury (which may contribute to swelling and brain damage) is due to an acute inflammatory response, the magnitude of which is dependent on the amount of tissue injury.

Acute-Phase Reaction↗
PubMed1994

The use of cytokines in children.

Cytokines play key roles in the control of hemopoiesis and immunity. As they become available in increasing quantities and purity through improved recombinant technology, cytokines hold great clinical promise. This article focuses on recent clinical experience with a wide variety of cytokines. For example, newer uses of recombinant human erythropoietin include treatment of anemia of prematurity, AIDS, and some hemoglobinopathies. The myeloid-stimulating factors have established a niche in the treatment of chemotherapy-induced neutropenias and as an adjunct to bone marrow transplantation. Combinations of cytokines that act at different levels of hemopoietic proliferation are being evaluated for the treatment of other causes of neutropenia and thrombocytopenia and also as biologic response modifiers.

Anemia↗
PubMed1994

Third- and fourth-generation implantable cardioverter defibrillators: current status and future development.

Implantable cardioverter defibrillator (ICD) therapy has become the mainstay of therapy for patients with a history of sudden cardiac death or life-threatening ventricular arrhythmias. The current generation of ICDs used for secondary prevention combines features for tachycardia reversion with demand ventricular pacing, antitachycardia pacing, programmable shock therapy, and tachycardia events memory. Although demand pacing and defibrillation is indicated for primary prevention usage of ICDs, the application of antitachycardia pacing modes is more controversial. High energy cardioversion and defibrillation shocks remaining the mainstay of sudden death prevention will be redefined as more effective defibrillation shock modes and lead systems are developed. Fourth-generation ICD systems accomplished a significant reduction of device size and almost universal success using an endocardial lead configuration and pectoral implant. A variety of new directions of ICD therapy in clinical practice such as primary prevention applications and the adjunctive role of antiarrhythmic drug therapy are currently being examined in clinical trials. The concepts underlying initiation of tachyarrhythmias are being studied to develop new approaches to tachycardia prevention. These include rate support, subthreshold stimulation, and multiple site pacing. The current developments of ICD therapy promise continued growth of this technology.

Anti-Arrhythmia Agents↗
PubMed1994

Chronic pancreatitis in late childhood and adolescence.

Acute pancreatitis is unusual in pediatric patients, and chronic pancreatitis is even less common. Between 1983 and 1988, we diagnosed 24 patients in late childhood and adolescence with chronic pancreatitis. Our review revealed that chronic pancreatitis presents as recurrent abdominal pain in late childhood and adolescence. Individual laboratory and radiological investigations may be normal during acute exacerbations of pain, but the determination of serum amylase and lipase concentrations--combined with ultrasonography--will accurately identify most patients. We found that endoscopic retrograde cholangiopancreatography is a valuable tool in the diagnosis of structural abnormalities. Surgical intervention may reduce symptoms in patients with structural abnormalities. There is a tendency toward decreased frequency and severity of pain as the patients increase in age.

Adolescent↗
PubMed1994

Phase I study of oral etoposide in children with refractory solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD), dose-limiting toxicity, and plasma concentrations of orally administered etoposide (VP-16) in pediatric oncology patients. PATIENTS AND METHODS: In a phase I study, 20 children with refractory solid tumors received oral VP-16 (the intravenous preparation diluted with sodium chloride) three times daily for 21 days. Daily dose levels studied were 50 mg/m2 (n = 5), 60 mg/m2 (n = 7), and 75 mg/m2 (n = 8). VP-16 concentrations were measured in blood samples collected on days 1, 7, 14, and 21. RESULTS: Grade 3 to 4 thrombocytopenia and/or neutropenia causing interruption of the 21-day course or persisting for more than 7 days after the last day of chemotherapy was seen at all dose levels, but was not dose-limiting. One patient treated at the 50-mg/m2 daily dose died of sepsis. At the 75-mg/m2 dose level, diarrhea was dose-limiting. Estimated plasma VP-16 concentrations were greater than 1 micrograms/mL for median periods of 9.4, 15.4, and 13.5 hours per day at daily doses of 50, 60, and 75 mg/m2, respectively. Responses were observed in seven of 14 patients who received at least one additional course of etoposide after a rest period of 7 days. There was one complete and two objective responses. Four patients were considered to have stable disease. CONCLUSION: The intravenous preparation of VP-16 administered orally appears to be well tolerated by heavily pretreated pediatric patients. On the three-times daily, 21-day schedule, a daily dose of 75 mg/m2 exceeds the MTD, with diarrhea as the dose-limiting toxicity. The recommended dose for oral etoposide is 60 mg/m2/d administered every 8 hours.

Administration, Oral↗
PubMed1994

The 5q- syndrome: a scientific and clinical update.

The 5q- syndrome is a subset of the myelodysplastic syndromes characterized by hypolobulated micromegakaryocytic hyperplasia and an interstitial deletion of the long arm of chromosome 5. In this concise review, we discuss the current understanding in regard to the genetic basis of the disorder and provide an updated clinical report on 43 patients with the disease who were seen at our institution.

Chromosome Deletion↗
PubMed1994

Bronchiolitis obliterans organizing pneumonia (BOOP) in children after allogeneic bone marrow transplantation.

Three pediatric patients of a cohort of 24 who underwent allogeneic bone marrow transplantation (BMT) from matched unrelated or mismatched family member donors developed low grade fever and cough between 2 and 3 months after BMT in the absence of clinical GVHD. Imaging studies revealed bilateral patchy opacities and open lung biopsies revealed the characteristic histological appearance of bronchiolitis obliterans organizing pneumonia. All three patients were treated with steroids and in two patients the syndrome resolved over 1-2 months; the third patient developed progressive pulmonary failure and died 2 weeks after diagnosis. BOOP may be an under-recognized respiratory complication following BMT from a matched unrelated donor or mismatched family member.

Adolescent↗
PubMed1993

The 5q- syndrome: a single-institution study of 43 consecutive patients.

A favorable prognosis and a low rate of leukemic transformation has been attributed to the 5q- syndrome, a myelodysplastic syndrome (MDS) characterized by macrocytic anemia, hypolobulated micromegakaryocytic hyperplasia, and an interstitial deletion of chromosome 5. We examined the characteristics and outcome of 43 consecutive patients in our institution strictly defined by morphologic criteria and a solitary 5q- cytogenetic defect. The median age at diagnosis was 68 years, with a clear female predominance (7:3). Eighty percent of the patients were red blood cell transfusion-dependent at diagnosis and all untransfused patients had macrocytic indexes. In contrast, significant neutropenia or thrombocytopenia was rare. The French-American-British (FAB) class distributions were RA (72%), RARS (7%), RAEB (16%), and RAEB-IT (5%). At a median follow-up of 31 months, 56% of the patients survive, with a projected median survival of 63 months. The incidence of acute leukemia was 16% and was uniformly fatal. Clinical hemosiderosis occurred in 28% of the patients, resulting in two deaths. Neither survival nor the risk of leukemic transformation was predictable from initial clinical parameters, including FAB classification, Bournemouth score, and degree of aneuploidy. The lack of significant neutropenia and thrombocytopenia seemed to account for a very low incidence of infection and bleeding resulting in a prognosis equal or superior to historical patients with MDS. Therapeutic endeavors, including the use of corticosteroids, androgens, cis-retinoic acid, pyridoxine, and danazol, were largely unsuccessful.

Acute Disease↗
PubMed1993

Acute subdural haematoma in the conscious patient: outcome with initial non-operative management.

We have retrospectively reviewed 23 conscious patients, in whom a CT scan diagnosis of acute subdural haematoma was made, and in whom craniotomy for evacuation was not initially performed. These highly selected patients represent 3% of 837 patients with acute subdural haematoma, presenting over a five year, eight month period to the Institute of Neurological Sciences, in Glasgow (1986-1991). Patients with any other associated intracranial abnormalities, such as cerebral contusions, as shown on CT, were excluded from this report. All patients were followed by serial CT scanning, and neurological assessments. Cerebral atrophy was present in over half of the sample. In 17 of our patients, the acute subdural haematoma resolved spontaneously, without evidence of damage to the underlying brain, as shown by CT or neurological findings. Six subsequently required burr hole drainage of a hypodense liquid subdural haematoma. In each of these patients, haematoma thickness was greater than 10 mm. Haematoma volume was significantly larger (53 +/- 6 ml versus 32 +/- 2 ml) in the group who came to operation. The mean delay between injury and operation in this group was 15 days. We conclude that certain conscious patients with small acute subdural haematomas, without mass effect on CT, may be safely managed conservatively.

Adolescent↗
PubMed1993

Intradural conus and cauda equina tumours: a retrospective review of presentation, diagnosis and early outcome.

This is a retrospective review of the clinical presentation, diagnosis and management of 62 patients with histologically proven intradural conus and cauda equina tumours. In the majority of cases the clinical presentation clearly suggests the need for further investigation. One fifth of the patients had small intramedullary tumours, which presented particular diagnostic difficulty and required sophisticated cross sectional imaging.

Adolescent↗
PubMed1993

Low-energy endocardial defibrillation using an axillary or a pectoral thoracic electrode location.

BACKGROUND: A significant proportion of patients receiving endocardial defibrillation lead systems must accept either high defibrillation thresholds (DFTs) with lower safety margins or lead implantation by thoracotomy. We examined the feasibility of achieving universal application of endocardial leads and lower defibrillation energy requirements by optimizing the lead system location in conjunction with biphasic shocks. METHODS AND RESULTS: Two defibrillation catheter electrodes were positioned in the right ventricle and superior vena cava. Thoracic patch electrodes were placed at three sites (apical, pectoral, and axillary). Fifteen-joule, 10-J, and 5-J bidirectional simultaneous biphasic shocks were delivered across three different triple electrode configurations (right ventricle, superior vena cava, and patch) after inducing ventricular fibrillation (VF), and DFT was determined. All patients in whom VF was reproducibly inducible (14 patients) could be reproducibly defibrillated at 15 J at one or more patch electrode locations. Fifteen-joule shocks were effective at three thoracic electrode locations in 12 patients and at two electrode locations in 6 patients. The lowest mean single-shock DFT was 8.1 +/- 3.8 J. In 4 patients, ventricular flutter was reproducibly induced and reverted at 15 J in all patients. Mean DFT for the axillary location was 8.3 +/- 3.5 J and was significantly lower than apical (12.8 +/- 5.6 J, P = .008) and pectoral (11.6 +/- 4.1 J, P < .04) patch locations. The probability of success was significantly higher at 10 J with axillary location (78% of patients, P < .03 compared with both other sites) and at 15 J (P < .05 compared with the apical location). Low-energy endocardial defibrillation (< or = 10 J) was feasible in 10 of 14 tested patients at more than 1 thoracic electrode location at 10 J, whereas only 1 of 7 successful patients could be reverted at more than 1 electrode location at 5 J (P < .02). CONCLUSIONS: The use of axillary or pectoral patch lead location can allow endocardial defibrillation with biphasic shocks at energies < or = 15 J in this lead configuration. Virtually universal application of endocardial defibrillation lead systems can be predicted from these data. Reduction in maximum pulse generator output to < or = 25 J using these two thoracic electrode locations with bidirectional shocks can be feasible and maintain an adequate safety margin and permit thoracic pulse generator implantation. Lowering endocardial defibrillation energy < 10 J requires increasing specificity of thoracic electrode location.

Aged↗
PubMed1993

Spinal cord infarction following meningitis.

A case of delayed onset of paraplegia following minor head injury and meningitis is presented. At operation extensive necrosis of the thoracic spinal cord was demonstrated. The possibility of spinal cord infarction is discussed.

Adult↗
PubMed1993

Detection & elimination of preanalytical errors in the determination of zinc in biological samples.

Exogenous contamination poses a major problem to accurate determination of trace metals in biological samples. Analysis of these elements in biological material entails adoption of special precautionary measures. In this study we have assessed the various procedural steps of sampling and analysis of zinc in order to identify and minimize extraneous contamination in the laboratory. In addition we have established reference limits (2 SD) for zinc in human plasma, erythrocytes and hair.

Adolescent↗