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Biomedical subjects

R R Smith

Publications and source records attributed to R R Smith.

At least 37 records · Page 2Linked to original sources
PubMed1998

Primary intravascular lymphomatosis associated with Mycobacterium marinum.

Intravascular lymphomatosis (i.v.l.) is a rare condition in which neoplastic cells preferentially infiltrate blood vessels of the central nervous system. Nonspecific symptoms associated with i.v.l. include dementia, seizures, and multifocal cerebrovascular events. i.v.l. was discovered at autopsy of a patient whose neurological deficits were predated by a particularly aggressive form of Mycobacterium marinum soft-tissue infection. It is speculated that i.v.l. may have had an occult effect on the patient's cell-mediated immunity that predisposed him to this normally innocuous mycobacteria.

Blood Vessels↗
PubMed1997

General practitioners as providers of minor surgery--a success story?

BACKGROUND: It is now recognized that many minor surgical procedures can be appropriately performed in a general practitioner setting; the government has introduced a list of minor operations, for which it is prepared to pay a limited fee, and it is now time to see whether this service can be expanded. AIM: To demonstrate that a group of general practitioners (GPs) with a particular interest in minor surgery can offer an expanded service both to their own patients and also to the patients of neighbouring colleagues, whether fundholding or non-fundholding, within a health authority area. METHOD: The West Kent Health Authority awarded a contract for 500 minor operations to a group practice of five GPs. At the end of the first year, 511 operations had been performed, and the results and implications are discussed. RESULTS: The target of 500 minor operations was met and passed in the first year. Thirty-five neighbouring GPs referred their patients directly. All were offered an initial appointment within one week and had their operation performed within one month, unless they had expressed a preference for an alternative date. Several unsuspected malignancies were discovered-no complications were recorded, patients' and referring doctors' satisfaction was high and the scheme was judged to have been a success in their eyes. CONCLUSION: GPs can provide an efficient, cost-effective minor surgery service, which is popular with patients and referring colleagues. Whether this is the way we wish to organize minor surgery in the future needs further discussion.

Delivery of Health Care↗
PubMed1996

Increased intracranial pressure and the cerebrospinal fluid spaces.

Increased intracranial pressure is a frequent accompaniment to many of the disease processes affecting the brain and its coverings. Such increased pressure is associated with significant morbidity and mortality. This article briefly reviews the pathophysiology of increased intracranial pressure and addresses the clinical and neuroradiological presentation of increased pressure. As part of the discussion, the concept of hydrocephalus and its treatment and complications are addressed.

Blood Volume↗
PubMed1996

Hematopoietic bone marrow hyperplasia: correlation of spinal MR findings, hematologic parameters, and bone mineral density in endurance athletes.

PURPOSE: To determine the frequency of hematopoietic hyperplasia on spinal magnetic resonance (MR) images in endurance athletes and to correlate MR alterations with clinical parameters. MATERIALS AND METHODS: In 15 endurance athletes, MR images of the lumbar spine were analyzed for hematopoietic hyperplasia; vertebral T1 and T2 were determined. Bone mineral density (BMD) was determined, blood tests were performed, and maximum oxygen consumption (VO2max) was measured. RESULTS: Nine subjects showed evidence of hematopoietic hyperplasia: Eight showed T1 prolongation, and six had patchy or diffuse T1 hypointensity. No definite correlation existed between hematopoietic hyperplasia and duration of training, hematologic results, or VO2max levels. Borderline significance existed between hematopoietic hyperplasia and anemia (P = .103) and intensity of training (P = .09). BMD had no statistically significant effect on T1. CONCLUSION: Changes in BMD do not appear to contribute to MR marrow changes that are consistent with hematopoietic hyperplasia. Depleted iron reserves or increased hematopoiesis probably contribute to hematopoietic hyperplasia in endurance athletes.

Adult↗
PubMed1996

Case report: CT and MRI of intracranial dermoid causing headache.

This case shows an unusual intracranial cause of chronic headache in a 30-year-old female. Computerized tomography and magnetic resonance imaging were used to demonstrate an intracranial, dermoid cyst located in the left middle cranial fossa. Droplets of fat-like material, which leaked from this cyst, were present in the basilar subarachnoid spaces and left sylvian fissure. Since the surgical excision of the cyst, the patient has not had any severe headaches.

Adult↗
PubMed1995

Gliofibroma: CT and MRI.

We describe CT and MRI appearances in two children with pathologically proven gliofibromas, in the cerebrum and cerebellum. A striking finding was lack of high signal on T2-weighted MRI.

Biomarkers, Tumor↗
PubMed1995

Spontaneous extracranial carotid artery dissection in children.

Dissection of cerebral arteries as a cause of stroke is rarely recognized in children. Two patients with stroke due to extracranial carotid artery dissection are reported. A 7-year-old girl with a 2-week history of right arm chorea had a left basal ganglia infarct and is receiving haloperidol for persistent chorea. The second patient, a 15-year-old boy, developed aphasia and right hemiparesis a day before admission during a football game without obvious trauma. He had a large left middle cerebral artery infarct and died of cerebral edema and herniation. We believe that strokes due to arterial dissection are more common than currently recognized, partly because of a lack of history of trauma, and suggest that cerebral artery dissection be considered as an etiology of childhood strokes. Greater awareness of arterial dissection as a cause of stroke and availability of noninvasive techniques like magnetic resonance angiography should result in a more accurate diagnosis and improved prognosis in these patients.

Adolescent↗
PubMed1995

Basal cell carcinoma of the sole.

Basal cell carcinoma (BCC) of the plantar surface of the foot is rare, with only 22 previously reported cases. This clinicopathologic study is based on 20 cases of BCC of the plantar surface and plantar-like surfaces from adjacent lower lateral and medial aspects of the foot, submitted to a large podiatric laboratory from 1986 through June 1992 (total specimens for this period = 518,624; total BCC of lower extremities, below knee = 53). There were 15 women and 5 men. The average patient age was 73 years, with a range from 52 to 92 years. The duration of the lesion before diagnosis was 2 months to 12 years, with an average of 2 years. Three patients had a history of trauma. Podiatric clinical diagnoses included BCC (4), SCC (3), soft tissue tumor (2), nevus (1), granuloma (1), keratosis (2), verucca (1), and psoriasis (1). Follow-up information was available on 10 patients; all were free of disease up to 64 months, with an average follow-up of 15.7 months. Three of 20 BCC showed predominant histologic patterns characteristic of fibroepithelioma of Pinkus (FEP). An additional three BCC showed focal or suggestive patterns of FEP. Fourteen tumors showed ordinary BCC histologic patterns. No multicentric-superficial or morphea like BCC were observed. The relatively high incidence of FEP in BCC of the sole correlates with abundant sweat glands and lack of hair follicles on the plantar surface, in accordance with the recent proposal that FEP derives its histologic pattern from the spread of BCC down eccrine ducts, eventually replacing them with solid strands of tumor.

Aged↗
PubMed1995

Chiari I malformation: association with hypophosphatemic rickets and MR imaging appearance.

PURPOSE: To evaluate for an association between familial hypophosphatemic rickets (FHR) and Chiari I malformation (CM1). MATERIALS AND METHODS: Sixteen patients with FHR underwent magnetic resonance (MR) imaging of the cervicomedullary junction. Images were analyzed by three radiologists for cerebellar tonsillar ectopia, syringohydromyelia, calvarial bone thickening, a flat posterior fossa, and cervical spinal stenosis. Final diagnoses were made by means of consensus. Tonsillar ectopia of 4 mm indicated CM1. Subjects underwent neurologic examination and completed a questionnaire. Medical records were retrospectively reviewed. A two-sided Fisher exact test was used to test for independence between CM1 and bone thickening or ventriculomegaly. RESULTS: Seven subjects (44%) had CM1. The more severe the bone thickening, the more likely that a CM1 was present. Four subjects (25%) had cervical spinal stenosis. CONCLUSION: Findings indicate that CM1 is associated with FHR and that the primary abnormality in patients with CM1 is a small posterior fossa caused by a bony malformation.

Adolescent↗
PubMed1994

Endothelial injury following experimental subarachnoid hemorrhage in rats: effects on brain blood flow.

BACKGROUND: The leading cause of death and disability in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) is cerebral vasospasm, a persistent, progressive, and often irreversible constriction of cerebral arteries. A wide array of pathological changes occur in cerebral arteries following SAH, with endothelial injury being the earliest and most consistent one. Since intact endothelium modulates many reflexes that influence vascular tone, damage to them may represent a significant contributor to cerebral vasospasm. METHODS: Changes in local cerebellar blood flow (LCBF) and pathological alterations in major cerebral arteries were studied and compared in rats at various time intervals following SAH. SAH induced by the subarachnoid injection of 0.3 ml of whole blood. Sham rats received a subarachnoid injection of 0.3 ml of isotonic saline. RESULTS: Except for an immediate but transient decrease, LCBF remained unchanged over a 3 day period following saline injection. Likewise, there were no pathological alterations in cerebral arteries of saline-injected rats. In contrast, the subarachnoid injection of whole blood produced significant changes in both LCBF and cerebral arteries. Within 30 minutes post-blood injection, LCBF became significantly decreased and remained so for 4 hours. However, within 24 hours, LCBF had returned to control levels where it remained for 3 days. Endothelial injury was observed in the basilar and middle cerebral arteries from 30 minutes through 4 hours, the same periods in which LCBF was significantly reduced. Within 24 hours, the time period in which LCBF had rebounded to control ranges, cerebral arteries showed no evidence of endothelial damage and resembled control cells. CONCLUSION: The results indicate a direct correlation between changes in LCBF and the structural integrity of endothelial cells in the early stages following SAH. The lack of chronically depressed LCBF (after 1 day) may be related to the quick structural repair of endothelium.

Animals↗
PubMed1994

MRI in acute disseminated encephalomyelitis.

A retrospective analysis of CT and MRI studies in 12 patients with a clinical diagnosis of acute disseminated encephalomyelitis (ADEM) was performed. MRI was the definitive modality for the assessment of the lesions of ADEM: all patients had abnormalities consistent with the clinical diagnosis. Ten had abnormalities in the brain, three spinal cord lesions, and three showed evidence of optic neuritis. CT was normal in 6 of the 7 patients in which it was performed.

Acute Disease↗
PubMed1994

Langerhans cell histiocytosis of bone: MR imaging.

Magnetic resonance (MR) images of 12 pathologically proven lesions of Langerhans cell histiocytosis (LCH) of bone were reviewed retrospectively. MR identified all lesions, three of which were not identified on plain radiographs. In all cases, MR showed greater abnormality than did plain radiographs. With one exception, all lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. The lesions and associated soft tissue abnormalities were very conspicuous on short TI inversion sequences and T1-weighted post-contrast images. Follow-up MR studies in two patients after chemotherapy showed decreased size and enhancement of lesions compared with baseline studies.

Adolescent↗
PubMed1994

Angioplasty of vasospasm: is it reasonable?

Clinical and radiographic examinations indicate preliminarily indications that transluminal angioplasty may be effective in overall management of the patient with vasospasm. Many questions remain, including: How does it work?; Are the effects persistent?; Is the arterial wall injured by the process? Recent studies in several patients who died after angioplasty allow us to provide some answers. Undilated spastic arteries show proliferation of both cellular and connective tissue elements. There is good evidence that myofibroblasts have reorganized the collagen framework, increasing fibril density and thus thickness. Dilated vessels show thinning of the arterial wall without disruption but with compaction of the new collagen fibrils. Cellular nests are also compressed and stretched. The endothelial layers are undisturbed. The success of dilatation depends on the amount and location of proliferation present. The effect is usually permanent. Because our protocols call for dilatation no greater than 10% above normal diameter, the muscle layers have not been torn or stretched although focal areas of necrosis are sometimes seen. Understanding the constrictive process and its relief through dilatation, allows us to formulate a therapeutic plan. Our experience in treating 89 patients with vasospasm after SAH suggests that, for best results, angioplasty should be performed before the angiopathic features become florid. This helps to preserve flow through the short arteries to the brain stem and deep brain nuclei, which may be involved indirectly in the vasospastic process.

Angioplasty, Balloon↗
PubMed1994

Hiccups and brainstem compression.

A 70-year-old man presented with a 12-year history of intractable hiccups. Magnetic resonance imaging and cerebral angiography revealed dolichoectasia of the right vertebral artery with compression of the brainstem at the pontomedullary level.

Aged↗