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Biomedical subjects

G S Rutherfoord

Publications and source records attributed to G S Rutherfoord.

At least 19 recordsLinked to original sources
PubMed2000

Proton relative biological effectiveness (RBE) for survival in mice after thoracic irradiation with fractionated doses.

PURPOSE: This study aims at providing relative biological effectiveness (RBE) data under reference conditions accounting for the determination of the "clinical RBE" of protons. METHODS AND MATERIALS: RBE (ref. (60)Co gamma-rays) of the 200 MeV clinical proton beam produced at the National Accelerator Centre (South Africa) was determined for lung tolerance assessed by survival after selective irradiation of the thorax in mice. Irradiations were performed in 1, 3, or 10 fractions separated by 12 h. Proton irradiations were performed at the middle of a 7-cm spread out Bragg peak (SOBP). Control gamma irradiations were randomized with proton irradiations and performed simultaneously. A total of 1008 mice was used, of which 96 were assessed for histopathology. RESULTS: RBEs derived from LD50 ratios were found not to vary significantly with fractionation (corresponding dose range, approximately 2-20 Gy). They, however, tend to increase with time and reach (mean of the RBEs for 1, 3 and 10 fractions) 1.00, 1.08, 1.14, and 1.25 for LD50 at 180, 210, 240, and 270 days, respectively (confidence interval approximately 20%). alpha/beta ratios for protons and gamma are very similar and average 2.3 (0.6-4.8) for the different endpoints. Additional irradiations in 10 fractions at the end of the SOBP were found slightly more effective ( approximately 6%) than at the middle of the SOBP. A control experiment for intestinal crypt regeneration in mice was randomized with the lung experiment and yielded an RBE of 1.14 +/- 0.03, i.e., the same value as obtained previously, which vouches for the reliability of the experimental procedure. CONCLUSION: There is no need to raise the clinical RBE of protons in consideration of the late tolerance of healthy tissues in the extent that RBE for lung tolerance was found not to vary with fractionation nor to differ significantly from those of the majority of early- and late-responding tissues.

Animals↗
PubMed1996

Cerebral infarction and intracranial arterial dissection in closed head injury.

This report describes the autopsy findings in three cases of closed head injury dying of cerebral infarction, with brain swelling and herniation. In each instance the cause of the infarct was found to be subintimal dissection involving intracranial anterior circulation arteries. The autopsy findings underscore the value of histological examination of vessels that macroscopically appear thrombosed. We discuss factors that impact on the reported incidence and make brief mention of problems surrounding the true pathogenesis of this lesion.

Adolescent↗
PubMed1995

Pleural Mesocestoides and cardiac shock in an obese vervet monkey (Cercopithecus aethiops).

Only one case of infection by tetrathyridia larvae of the tapeworm genus Mesocestoides was detected in 416 necropsies of captive vervet monkeys (Cercopithecus aethiops). Two hundred nine larvae were distributed between both pleural cavities. Mass and size ranges of larvae were determined. A plasma cell reaction indicated a humoral immune response to parasite antigens, which may have contributed to acute, lethal cardiac shock. Coagulative myocytolysis was confirmed. The history of this case and associated circumstantial evidence and reports in the literature suggest that infection of primates by tetrathyridia probably occurs after capture rather than before.

Animals↗
PubMed1995

Semiquantitative postembedding characterization of intermediate filaments in central nervous system lesions using immunoelectron microscopy.

Standardized postembedding immunoelectron microscopy was performed to demonstrate glial fibrillary acidic protein (GFAP) and vimentin in individual intermediate filaments to determine the diagnostic value of demonstrating ultrastructural and immunophenotypic characteristics of intermediate filaments in routine brain biopsy specimens. Dual expression of GFAP and vimentin was observed in the astroblastoma and astrocytes of Alexander's disease. The antigen availability for vimentin, however, was too low to allow reliable assessment of the GFAP:vimentin ratio in individual intermediate filaments and/or filament bundles. In meningioma, only vimentin positive intermediate filaments were found. GFAP positive intermediate filaments were present in all other specimens except the oligodendroglial components of the mixed glioma, which were devoid of intermediate filaments. GFAP positivity in the filamentous periphery and electron-dense core of Rosenthal fibers was demonstrated. Technical and tissue processing factors had a significant effect on particle density values obtained for individual specimens. Although the number, distribution, and density of glial intermediate filaments varies in different astroglial entities, correlation of particle density values determined by immunoelectron microscopy with relative GFAP concentrations in different lesions requires utmost caution. Nevertheless, application of the postembedding approach to routinely fixed biopsy specimens indicated an association of different entities with the exclusive presence of GFAP and/or vimentin in individual intermediate filaments, thus emphasizing the diagnostic value of intermediate filament typing for pathological characterization.

Adolescent↗
PubMed1993

Shotgun pellet embolism to the brain.

This report describes the autopsy findings in a young man who died after having been shot with a shotgun from about 30 m. Although not suspected clinically, a right middle cerebral artery territory infarct was found; its cause was shown to be a shotgun pellet embolus that had lodged just proximal to the trifurcation of the right middle cerebral artery. The case underscores the importance of performing a thorough postmortem examination, including a careful study of cerebral vasculature, in instances of brain infarction.

Abdominal Injuries↗
PubMed1993

Medicolegal aspects of cerebral amyloid angiopathy. A case report.

Autopsy examination performed on a 75-year-old woman who had been in a minor road traffic accident revealed an occipital lobar hematoma with subdural extension. Histological examination of brain tissue showed the presence of severe cerebral amyloid angiopathy. Diagnostic techniques and correlation and interpretation of these findings are discussed.

Accidents, Traffic↗
PubMed1989

Lafora-body disease with optic atrophy, macular degeneration and cardiac failure.

A 17-year-old boy was admitted to hospital in acute cardiac failure and psychosis. The clinical course, EEG records and tissue diagnosis, including biopsies of brain, skin, skeletal muscle, peripheral nerve and liver were compatible with Lafora-body disease (LBD). Unusual features were those of optic atrophy and macular degeneration, signs generally regarded as negative criteria for the diagnosis of this disease. We also present the findings on endomyocardial biopsy which was performed because cardiac failure as an early symptom of LBD has not been previously described. The patient died in status epilepticus a few months after discharge from hospital.

Adolescent↗
PubMed1987

Chordomas--ultrastructure and immunohistochemistry: a report based on the examination of six cases.

Six chordomas (three classic and three chondroid) were examined ultrastructurally and with a panel of monoclonal antibodies. The three classic tumours showed the presence of desmosomes and intermediate filaments on electron microscopy, findings which gave a direct positive correlation when the tumours were stained with monoclonal antibodies against low molecular weight cytokeratin proteins. These results suggest that chordomas are essentially epithelial neoplasms and underline the fact that monoclonal antibodies to cytokeratins cannot be used in the differential diagnosis of classic chordoma vs carcinoma. Furthermore, the epithelial characteristics are lost as the tumour undergoes chondroid differentiation.

Adult↗
PubMed1986

Malignant glioma following radiotherapy for unrelated primary tumors.

Four cases are documented where a glioma was histologically verified in the irradiation field of a previously treated malignancy of a different cell line. Radiation-induced neoplasia in the central nervous system now has been established in the induction of meningioma and sarcoma. The association between therapeutic irradiation and glioma in the reported cases lends to the evidence that a causal relation does exist. This incidence is small and does not detract from the overall benefit of irradiation as a therapeutic modality.

Adult↗
PubMed1986

Amoebic meningo-encephalitis due to a free-living amoeba. A case report.

A 47-year-old man developed an undiagnosed encephalitic illness and died within 12 days. Autopsy showed focal granulomatous lesions associated with a necrotizing vasculitis. Light microscopy revealed the presence of free-living amoebae morphologically resembling Acanthamoeba species. The pathology of this form of meningo-encephalitis is contrasted with that caused by Naegleria fowleri infection, and attention is drawn to its existence within the RSA.

Amebiasis↗
PubMed1985

Metastasizing pineal germinoma. A case report and review.

A patient with biopsy-proven pineal germinoma was treated successfully by craniospinal irradiation. Lung and hilar node metastases developed 22 months after therapy. These were subtotally resected and further cis-platinum, vinblastine and bleomycin chemotherapy given with control 8 months later. Twenty cases of metastases from pineal tumours are documented. The role of chemotherapy as adjuvant therapy, and in recurrent and metastatic disease is reviewed.

Adolescent↗
PubMed1985

Pineal tumours at Groote Schuur Hospital, 1976-1984.

Since 1976, surgical approaches to the pineal region have been undertaken at Groote Schuur Hospital. Thirty cases presenting with a clinical and investigative diagnosis of pineal tumour have been reviewed with respect to epidemiology, surgery, histological subtypes and metastatic pattern. The postoperative management with radiotherapy in the different histological subtypes is discussed. The prognosis for germ cell and benign tumours is good, with 100% control, but pineal parenchymal tumours and astrocytomas have not fared as well.

Adolescent↗
PubMed1983

Epsilon-aminocaproic acid-induced myopathy. A case report.

The prolonged administration of epsilon-aminocaproic acid (EACA) resulted in the development of severe proximal myopathy associated with high plasma creatine kinase values, rhabdomyolysis, myoglobinuria, and mild hyperbilirubinaemia. Withdrawal of the drug led to spontaneous resolution of the clinical and biochemical syndrome. Structural and enzyme studies of a biopsy specimen of the involved skeletal muscle supported the presence of subclinical myopathy. The mechanism whereby EACA produces its toxicity in muscle may in part be due to inhibition of cathepsin D, but the possibility that other proteases are involved has not been excluded. The fact that this clinical syndrome is rare despite the widespread use of EACA may be because it only occurs in subjects with a subclinical skeletal muscle disorder which is unmasked by the drug.

Adult↗