Biomedical subjects
Publications and source records attributed to P G Lynch.
Here we report the first noted case of a small cell carcinoma of the lung (oat cell carcinoma) presenting as metastases in the patella. Malignancies of the patella, primary or secondary, are rare. First presentation of a malignancy with metastases in the patella has only been recorded once previously.
We present a case of spinal meningeal melanocytoma involving the C5 nerve root with spinal cord compression which resembled a neurinoma clinically as well as radiologically. The clinical, radiological and pathological features of this and 11 other cases reported in the literature are reviewed. The significance of correct diagnosis and aggressive surgical management of this benign neoplasm is emphasized.
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There have been no reports of changes in free radical inactivating enzymes in the anterior horn of the spinal cord in ALS despite great interest in the possibility that free radicals might be important in the aetiology of the disease. In this study we have measured copper/zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GSHPX) activities in anterior horn tissue obtained from patients with ALS and from controls. Total SOD activity was no different in the anterior horn of ALS cases compared to controls, but Cu/ZnSOD activity was reduced, and that of MnSOD increased, at thoracic cord level only. No detectable activity of GSHPX or cytochrome P450 (unpublished data) was found. These latter negative findings are important because they suggest that generation of free radicals from exogenous chemicals is not important in ALS and further that the neurone (as compared to other cell types) is poorly protected against the toxicity of hydrogen peroxide.
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Two rare cases of intracranial meningeal melanocytoma are reported with clinical, radiologic, and pathologic findings. In one of these the diagnosis was established by ultrastructural studies that showed premelanosomes and melanosomes in nonarachnoid-derived tumor cells. The other case was diagnosed retrospectively after a very long survival and is still alive 35 years after total excision and radiotherapy. The occurrence of these tumors in the cerebellopontine angle is rare as seen in our case.
In vitro pulsatile flow visualization studies were conducted to assess the effects of varying radii of curvature of the right ventricular outflow tract (RVOT) and main pulmonary artery (MPA) on the flow fields in the main, right, and left pulmonary arteries of a one month lamb pulmonary artery model. Three glass flow-through models were studied; one with no curvature, one with the correct anatomic curvature, and one with an overaccentuated curvature on the RVOT and MPA. All other geometric parameters were held constant. Pulsatile flow visualization studies were conducted at nine flow conditions; heart rates of 70, 100, and 140 bpm, and cardiac outputs of 1.5, 2.5 and 3.5 l/min with corresponding mean pulmonary pressures of 10, 20, and 30 mmHg. Changes were observed in the pulmonary flow fields as the curvature of the outflow tract, heart rate and mean pulmonary pressure were varied. An increase in vessel curvature led to an increase in the overall radial nature of the flow field as well as flow separation regions which formed faster, originated further downstream, and occupied more of the vessel area. At higher heart rates, the maximum size of the separation regions decreased, while flow separation regions appeared earlier in the cardiac cycle and grew more quickly. Heart rate also affected the initiation of flow reversal; flow reversal occurred later in the cardiac cycle at lower heart rates. Both heart rate and mean pulmonary pressure influenced the stability of the pulmonary flow field and the appearance of coherent structures. In addition, an increase in mean pulmonary pressure increased the magnitude of reverse flow.(ABSTRACT TRUNCATED AT 250 WORDS)
Intraparenchymatous schwannomas of the central nervous system are rare. In decreasing order of frequency they are found in the spinal cord, cerebral hemispheres, brainstem and cerebellum. So far, only six such tumours have been reported in the cerebellum. A male predominance and early onset of symptoms are salient features. A case of a 73-year-old Caucasian female with an intraparenchymatous schwannoma of the right cerebellar hemisphere which extended into the brainstem is reported. A complete cure followed surgical removal of the tumour. The preoperative clinical and radiological diagnosis was that of a cerebellar astrocytoma.
Cerebral infarction due to fungal arteritis is an uncommon complication of neurosurgical operations and adjuvant immunosuppressive therapy, including long-term steroids. If unrecognized, the neurological deterioration which ensues may be mistreated by increasing the dose of steroids. A case of a 38-year-old Caucasian male who had no obvious immune deficiency or fungal infection prior to a craniotomy for cerebral tumour is described in whom perioperative aspergillus infection resulted in cerebral arteritis and extensive cerebral infarction with a fatal outcome. Long-term steroid therapy used in the management of cerebral tumours may carry an increased risk of systemic or cerebral fungal infection. The possibility of cerebral mycosis (arteritis) and dangers of its non-recognition are highlighted.
A retrospective study of 24 patients with primary non-Hodgkin's cerebral lymphoma (non-immunocompromised) is presented. All patients were seen at the Royal Preston Hospital, Lancashire between 1976 and 1991. Fifteen patients were over the age of 50 years (range 27-84). The commonest clinical presentation, seen in 16 patients was of an expanding space-occupying lesion. The diagnosis was suspected from the radiological findings but confirmation in every case was by histological examination of biopsy or necropsy material. The tumours were treated either by surgical excision or by biopsy and radiotherapy. Chemotherapy was given in two patients. Despite these measures the mean survival time was 3.6 months. The clinical radiological and pathological features of these tumours are highlighted with particular emphasis on the use of stereotactic biopsy, immunohistochemistry and chemotherapy in diagnosis and treatment.
A randomised controlled crossover trial was performed to assess the anti-anginal effects of nifedipine and propranolol separately and together. The effects of these treatments on blood pressure and heart rate were assessed at rest and after the cold pressor and mental arithmetic tests. Nifedipine and propranolol together produced the greatest reduction in supine and erect systolic and diastolic blood pressures. Propranolol (480 mg daily) lowered resting systolic/diastolic blood pressures by 7/6 mm Hg and nifedipine (60 mg daily) lowered it by 10/8 mm Hg, while in the erect position the hypotensive effect of these agents averaged 9/8 mm Hg. During the cold pressor test propranolol lowered the maximum pressure by an average of 11/6 mm Hg and nifedipine by 19/10 mm Hg. For the mental arithmetic test, the results were 7/2 mm Hg and 16/7 mm Hg respectively. Propranolol (480 mg daily)reduced supine and erect heart rate by 19 and 25 beats/minute respectively, while nifedipine did not alter heart rate significantly. The favourable haemodynamic responses to nifedipine suggest that it may be of value in the management of hypertension.
The antianginal effects of two active drugs, nifedipine and propranolol, alone in combination, were compared with those of placebo in a double-blind clinical trial that included 16 patients with chronic stable angina triggered by exertion. A low dose and a high dose of the active drugs were used (nifedipine, 30 and 60 mg/day; propranolol, 240 and 280 mg/day). Precordial exercise mapping and continuous electrocardiographic recordings were used to assess objective response to therapy, and the patients were asked to keep a diary of episodes of chest pain and consumption of nitroglycerin tablets for subjective appraisal. Both frequency of chest pain and nitroglycerin consumption were significantly reduced by each of the active drugs when compared with placebo, and the combination of nifedipine and propranolol added significantly to the effectiveness. Reductions in area of ischemia and number of episodes of ST segment depression on 48-hour ambulatory electrocardiographic monitoring corroborated the efficacy of each active treatment with respect to placebo. Nearly 60 percent of all episodes of ST segment depression were painless and responded to the active treatment in the same manner as did the episodes associated with chest pain. Side effects were mild and all treatments were well tolerated. The objective methods used allowed for clear-cut differentiation of treatment effects with the various regimens. Although the two drugs alone were significantly more effective than placebo, their combination provided an even greater improvement (p less than 0.005), and therefore it appears to be a safe and effective form of treatment for chronic stable angina.
Observations are presented on 3 patients, including one autopsy report, with peripheral neuropathy due to perhexilene maleate (Pexid). Clinically and biochemically perhexilene neuropathy presents features unusual for a drug-induced neuropathy. Patients liable to develop neuropathy can be recognised from clinical criteria or by the use of routine electrophysiological determinations of nerve conduction velocities. At this stage the neuropathy is readily reversible if perhexilene therapy is discontinued. We have sought to examine the problems entailed in the future safety of perhexilene and allied drugs.
A transmission electron microscope study was made of eight childhood brain tumors divided up into three zones, center, edge, infiltrating zone, and also of adjacent "normal-looking" brain. In seven of eight tumors, the numbers of Weibel-Palade bodies in endothelial cells were significantly increased in peripheral zones compared with central zones. A similar significant increase was observed after treatment of chick chorioallantoic membranes with tumor angiogenesis factor. It is suggested that large numbers of Weibel-Palade bodies may be a marker for proliferating endothelial cells in vivo.
Five intracranial meningiomas showing mixed mesenchymal differentiation are described. Three contained cartilage, three contained bone, four contained hyaline fibrous strands or nodules which in two instances were calcified, three contained angiomatous areas, one contained pericytoma-like areas, four contained pleomorphic and sometimes multinucleate giant cells, and one contained a mucoid matrix including spheroidal cells superficially resembling chordoma. The importance of recognising such tumours is emphasised as they can be misdiagnosed as metastatic deposits, particularly in a frozen section.
The clinical features and investigative findings of 50 patients with chronic progressive external ophthalmoplegia (CPEO) were analysed. The group was found to be clinically, genetically and histologically heterogeneous. With the possible exception of patients with "ophthalmoplegia plus," namely those who in addition to muscular weakness had evidence of central and/or peripheral nervous system abnormality, there was no apparent justification for separating out from among the group patients' subgroups which were distinctive enough to be recognized as syndromes. CPEO therefore seems to represent a number of different degenerative disorders whose common denominator is ophthalmoplegia and for which there are to date no adequate criteria for further classification.
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A family is described in which a hereditary peripheral neuropathy occurs, inherited as an autosomal dominant character. The syndrome is present at birth and does not show any significant progression thereafter. Three of the cases have suffered from arthrogryposis multiplex congenita. A secondary myopathy is also present. The condition appears to be intermediary between peroneal muscular atrophy and Friedreich's ataxia. Appearance at birth, presence of arthrogryposis multiplex congenita, and the non-progressive nature separate it sharply from the other heredofamilial ataxias and peripheral neuropathies.