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Biomedical subjects

A Gregor

Publications and source records attributed to A Gregor.

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

Radiotherapy of lung cancer.

Radiotherapy is the most common nonsurgical treatment for patients with lung cancer. Its value in controlling specific cancer related symptoms is undisputed and can be achieved with unsophisticated and undemanding schedules. However, these treatment regimens cannot be expected to produce durable local control or significant impact on survival. Their use cannot be generally accepted for all inoperable patients. The use of high-dose radiotherapy with curative intent has been brought into disrepute by often inappropriate patient selection and subsequently poor results. In a number of small pilot studies, survival comparable to surgical series can be achieved in operable patients. Safe delivery of high-dose radiotherapy to intrathoracic tumours represents a formidable technical challenge. The sophisticated treatment planning which is necessary and consistent diagnostic evaluation is often lacking in practice when the value of local therapy is perceived as minimal. Recent developments in radiation technology, tumour biology and understanding of normal tissue responses bring an opportunity to design new and more effective treatment schedules. New developments in systemic therapy far from making thoracic irradiation obsolete, demand higher rates of durable local control. The interrelationships between toxicities to normal tissues and potential advantage in antitumour activity bring further challenges in design of optimal combined modality schedules. The challenge facing the Radiation Oncologist interested in thoracic malignancies is how to balance the multiple and often conflicting possibilities and formulate novel schedules that can be evaluated in practice. A further challenge is how to facilitate the introduction of these resource-intensive strategies into the real world of shrinking resources and increasing waiting lists. The potential gains may be individually small but with the numerical importance of lung cancer may have a global impact.

Combined Modality Therapy↗
PubMed1995

Immunohistochemical and ultrastructural studies of stromal cells in hemangioblastoma.

In order to shed more light on the controversial tissue histogenesis of the stromal cells (SC), light microscopic, immunohistochemical and electron microscopic studies were performed on surgical specimens of hemangioblastomas (36, 26 and 7 cases, respectively). SC were immunoreactive for vimentin, S-100 protein, and neuron specific enolase (NSE) in all cases. Occasional SC were also positive for desmin, smooth muscle actin, Factor VIII, Ulex europaeus lectin receptors, GFAP, and Factor XIIIa. However, majority of these cells were negative with all the endothelial and smooth muscle cell markers used. Electron microscopy demonstrated several different types of SC that were reminiscent of pericytes, smooth muscle cells and abnormal endothelium as well as the intermediate forms between all the above cell types. Few SC were found lining the vascular lumina. Some SC formed small cavities reminiscent of early capillaries. However, typical Weibel-Palade bodies were not found in these SC. It is concluded that SC represents a heterogeneous population of lipidized cells, derived predominantly from the vasogenic mesenchyme. Although immunohistochemistry failed to reveal any consistent antigenic property of SC, ultrastructural findings strongly support the hypothesis that these cells are modified or abnormally differentiated endothelial cells and pericytes.

Adolescent↗
PubMed1994

Recording neurological impairment in clinical trials of glioma.

The criteria for clinical response to treatment in cerebral glioma remain poorly defined, but could be made more objective if simple measures of neurological impairments were included in the definitions. We assessed the utility of simple fast previously validated tests of limb impairment (Timed nine hole peg test and 10 meter walk), memory (Williams delayed recall test) and language (Boston Aphasia Severity Rating Scale) in fifty patients with primary brain tumours to see if they could act as a surrogate for neurological impairment. The tests were compared with established measures of physical disability (Barthel Disability Index [BDI]) and handicap. Timed tests of hand function and gait were sensitive to minor impairments and were abnormal in patients with physical disability on BDI. Timed tests correlated well with handicap (rank correlation 0.734). Short term memory was impaired more commonly with tumours involving the left hemisphere (p < 0.01). Dysphasia limited testing of memory in 8%. Depression was associated with problems in limb function (p < 0.01), memory (p < 0.001), language (p < 0.001), BDI (p < 0.001) and handicap (p < 0.001). The number of abnormal fast tests also correlated with the severity of handicap (rank correlation 0.786) indicating that memory impairment and aphasia contribute to handicap and should be assessed. Median time to complete all assessments was 7 minutes 20 seconds. Utilization of these simple tests will add sensitivity and objectivity to evaluation of neurological response in clinical trials and can be performed quickly by non medical staff.

Adolescent↗
PubMed1994

Hypofractionated radiotherapy as palliative treatment in poor prognosis patients with high grade glioma.

We report the palliative effectiveness of a hypofractionated radiotherapy regimen in patients with poor prognosis high grade glioma. Thirty-eight elderly, and/or disabled patients received radiotherapy to a dose of 30 Gy in 6 fractions over 2 weeks to a planning target volume defined by the enhancing tumour and a 2-cm margin. The median survival was 6 months with a 1-year survival rate of 23%. Treatment was without acute toxicity. One month after radiotherapy, functional status, assessed using a verbally administered Barthel index, improved in 38% and remained stable in a further 39% of surviving patients. At 3 months 39% of surviving patients had improved and a further 12% remained stable. We conclude that in the poor prognostic group of patients with high grade glioma hypofractionated partial brain radiotherapy is well tolerated, convenient and provides effective palliation in a proportion of patients. Comparison with conventional radiotherapy or symptomatic care alone require further evaluation in randomised studies.

Activities of Daily Living↗
PubMed1994

International survey of radiotherapy practice for radical treatment of non-small cell lung cancer.

This postal survey was designed to assess the possible agreement or differences in staging, selection criteria and radiation volumes for a curative treatment of non-small cell lung cancer. The questionnaire was sent to 263 radiotherapists from 38 different countries; 114 responses (43%) were received. In this sample, some geographical differences, mainly for staging procedures (the use of brain CT scan or bone scan) and selection criteria (the role of positive mediastinal lymph nodes), were seen. There was a good agreement between radiotherapists in the choice of treatment volumes in the five different clinical scenarios. The clinical and radiobiological findings of the last decade have discredited the routine use of split course or hypofractionation schedules. Further studies are needed to improve the technical basis of thoracic radiotherapy.

Carcinoma, Non-Small-Cell Lung↗
PubMed1994

Neurological and cognitive impairment in long-term survivors of small cell lung cancer.

Despite its effectiveness in reducing the rate of brain metastases, the role of prophylactic cranial irradiation (PCI) in the management of small cell lung cancer (SCLC) remains controversial because of concern about radiation-induced neurological morbidity. In order to evaluate morbidity and its impact on quality of life 64 patients surviving > or = 2 years in remission were recalled for assessment. 52 had received PCI. Most of the patients were well: 95% had performance status < or = 1 and nine out of 37 neurological examinations were abnormal. On neuropsychometric testing, only 19% of patients performed at the level expected for their age and intellectual ability on all four tests used. Fifty-four per cent of patients were impaired on two or more of the tests, suggesting a significant degree of measurable cognitive dysfunction. The number of patients who had not received PCI was insufficient for comparative analysis with the number who had, but among those treated with PCI, patients receiving 8 Gy in 1 fraction appeared less impaired than those receiving higher radiation doses in multiple fractions. The study showed that neuropsychometric testing is acceptable to patients, can be administered by non-psychologists in the clinic and is sensitive to otherwise undetected deficits of cognitive function in this patient population. Prospective evaluation of PCI should include neuropsychometric testing.

Adult↗
PubMed1994

Incidence of second brain tumours after pituitary irradiation in Edinburgh 1962-1990.

Two hundred and ninety-six patients irradiated for pituitary adenoma in Edinburgh between 1962 and 1990 were reviewed. The number of subsequent tumours was noted. The expected incidence of tumours was estimated, based on data from the Scottish Cancer Registry, for an age and sex matched population. One malignant brain tumour was found; the expected incidence was 0.3 (95% CI 0-12). One meningioma was reported. Thirty non-CNS tumours were found, compared with an expected incidence of 17.5 (95% CI 12-26). We see no reason at present to alter our practice as a result of radiation induced neoplasia in this group, although close follow-up continues.

Adenoma↗
PubMed1994

Can long-term survival be improved in patients with small-cell lung cancer (SCLC) and good performance status? Medical Research Council Lung Cancer Working Party.

Results from a long-term follow-up suggest that in patients with limited small-cell lung cancer (SCLC) and normal performance status intensive alternating chemotherapy and radiotherapy improve long-term survival rates. In a non-randomised study, 22 patients with SCLC of limited extent and good performance status were prescribed six cycles of etoposide, doxorubicin, cisplatin and cyclophosphamide at 4 week intervals with doses of thoracic radiotherapy following the second, third and fourth cycles. Although only six patients received all their prescribed treatment, nine (41%) were alive at 1 year, seven (32%) at 2 years, six (27%) at 3 years, and four are still alive at, respectively, 42, 47, 50, and 61 months, all four being in the subgroup of eight patients with WHO performance status grade 0 at the start of treatment. In a comparison with similar patients receiving conventionally scheduled chemotherapy and radiotherapy in a concurrent trial, no difference in survival was seen in the patients with performance status grade 1 or 2, but a large difference in favour of the alternating schedule in those with grade 0 status was seen. We encourage other investigators to report the results achieved with intensive treatment in patients with WHO grade 0 performance status at the start of treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Single photon emission computed tomography in long-term survivors of adult brain tumours.

Sixteen patients with primary brain tumours were examined on average eight years after treatment with surgery or whole brain irradiation using standard clinical assessment, CT, a neuropsychological test battery, and single photon emission CT (SPECT) with 99mTc-exametazime. Seventeen lesions were discovered on inspection of SPECT images, 11 with x-ray CT. Quantitative assessment of tracer uptake compared with 16 matched healthy volunteers was consistent with the presence of lesions. Measurement of uptake in brain regions of the hemisphere not containing the primary tumour still showed significant reductions in patients. This may be due to remote direct effects of the tumour or, more likely, to the whole brain irradiation received. Psychometric performance on most tests was significantly impaired in the patient group and was correlated with abnormalities of tracer uptake to relevant brain regions.

Adult↗
PubMed1994

Coexistence of hereditary coproporphyria with acute intermittent porphyria.

A new form of acute hepatic porphyria with double genetic defect--deficiency of porphobilinogen deaminase and coproporphyrinogen oxidase--is described. Among 17 studied family members this double enzymatic deficiency was found in five individuals, deficiency of porphobilinogen deaminase in four, and deficiency of coproporphyrinogen oxidase in two. Only the proband had an attack of porphyria. Apart from the proband, all family members had normal urinary PBG excretion. Increased faecal coproporphyrin excretion was found in three people. The results obtained suggest that deficiency of porphobilinogen deaminase and coproporphyrinogen oxidase can be inherited independently. coproporphyrinogen oxidase can be inherited independently.

Adolescent↗
PubMed1993

Immunoelectron microscopic localization of monoclonal IgM antibodies in gammopathy associated with peripheral demyelinative neuropathy.

A sural nerve biopsy from a patient with benign monoclonal IgM kappa gammopathy and sensory-motor demyelinative neuropathy, revealed marked loss of myelinated fibers and focal axonal degeneration as well as widespread demyelination and remyelination with onion-skin formation. Almost all myelinated fibers displayed characteristic widening of the myelin lamellae as well as excessive thickness and/or exuberant outfoldings of myelin, reminiscent of that seen in tomaculous neuropathy. Many endoneurial capillaries were lined by fenestrated endothelium, indicating breakdown of a normal blood-nerve barrier. The endoneurium contained large amounts of extracellular proteinaceous material. Immunofluorescence and immunoelectron microscopy performed on the nerve of the patient, demonstrated selective deposition of IgM kappa gammaglobulin, exclusively in the areas of splittings of the myelin lamellae. Schwann cells contained cytoplasmic myelin debris labelled with IgM kappa only. In the indirect immunofluorescence and immunoelectron microscopy, serum of the patient reacted with the whole thickness of compact peripheral myelin of a normal human nerve. There was no immunoreactivity with the central myelin, Schwannoma cells, glial cells, axons or neurons. Demonstration of the selective presence of monoclonal IgM in widened lamellae of myelinated fibers, as well as bound to the internalized myelin debris in Schwann cells and macrophages, indicates a pathogenetic role of monoclonal paraprotein in myelin injury. Demyelination is promoted by development of endothelial fenestrations in the endoneurial capillaries and breakdown of the blood-nerve barrier.

Aged↗