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Biomedical subjects

R R Smith

Publications and source records attributed to R R Smith.

At least 109 records · Page 6Linked to original sources
PubMed1988

Surgery of tumors invading the cavernous sinus.

Potential injury to neurovascular structures within the cavernous sinus often prohibits total removal of various cranial base tumors. This report discusses the rationale of direct cavernous sinus surgery and describes a surgical technique refinement as evolved from experience in 18 histologically benign operative cases. The nature of tumor extension mandated entry to the sinus, either through the superior or lateral wall or both. The operative microscope facilitated dissecting and preserving the carotid artery and cranial nerves transversing the sinus. Venous bleeding was controlled by packing. There was one death unrelated to cavernous sinus surgery. Five patients, however, had complications related to cavernous sinus surgery, including hemiplegia in one patient and cranial nerve palsy in four.

Adolescent↗
PubMed1988

Doppler echocardiographic comparison of haemodynamic results of one- and two-stage anatomic correction of complete transposition.

Eighteen children who had single-stage and 18 who had two-stage anatomic correction of complete transposition between the ages of 1 week and 3 years (mean 6.5 months) were investigated with pulsed and continuous wave Doppler ultrasound. Peak mitral flow velocities showed no significant difference from normal after single-stage correction, but were significantly higher than normal after two-stage correction (P less than 0.05). Peak tricuspid flow velocities were significantly higher than normal in both groups (P less than 0.02 and P less than 0.001). There was no significant difference in pulmonary artery flow velocities between the two groups, which were means (SD) of 214 (84) cm/sec after single-stage and 179 (87) cm/sec after two-stage repair. Peak velocities in the ascending aorta were within normal limits after single-stage correction, but were lower than normal in the two-stage group (P less than 0.02). Mild aortic regurgitation was detected in 22% of single-stage and 55% of two-stage patients (P = 0.043, 2P = 0.085). Both types of repair are associated with higher peak tricuspid flow velocities than normal and have a similar incidence of mild supravalvar pulmonary stenosis. Mitral flow velocities are higher than normal only after two-stage correction. Velocities in the ascending aorta are lower than normal and the incidence of mild aortic regurgitation appears to be increased after two-stage repair, probably due to dilatation of the aortic root following banding of the pulmonary trunk.

Aorta, Thoracic↗
PubMed1988

Prevalence and characteristics of Barrett esophagus in patients with adenocarcinoma of the esophagus or esophagogastric junction.

The prevalence and characteristics of Barrett esophagus in patients with adenocarcinoma of the esophagus or esophagogastric junction are uncertain. We studied 61 consecutive esophagogastrectomy specimens with adenocarcinoma, which were subjected to extensive histopathologic examination. Barrett esophagus was found in 64% of the cases (39 of 61), but had been recognized in only 38% of the patients with Barrett-associated carcinoma who had undergone preoperative endoscopy with biopsy (13 of 34). The median extent of Barrett esophagus with adenocarcinoma was 5 cm (range, 1 cm to 12 cm), and distinctive-type ("specialized") Barrett mucosa predominated (35 of 39; 90%). The Barrett adenocarcinomas were centered in the distal esophagus 2 cm +/- 0.3 cm above the esophagogastric junction. The patients with Barrett adenocarcinoma showed a striking predominance of white men (34 of 39; 87%) in contrast to gastric adenocarcinoma cases (21 of 69; 30%) and to Barrett patients without carcinoma or dysplasia (75 of 149; 50%), but similar to patients having adenocarcinoma of the esophagus or esophagogastric junction without demonstrable Barrett esophagus (16 of 22; 73%). Our findings suggest that most adenocarcinomas of the esophagus or esophagogastric junction are Barrett carcinomas, rather than gastric cardiac cancers or other types of esophageal adenocarcinoma; most Barrett adenocarcinomas occur in short segments of Barrett esophagus, which may be difficult to detect at endoscopy; and white men with Barrett esophagus may constitute a clinically identifiable at-risk group suitable for surveillance.

Adenocarcinoma↗
PubMed1988

Subarachnoid haemorrhage produces differential effects on transmitter kinetics at cerebral periarterial noradrenergic terminals.

The functional states of cerebral perivascular noradrenergic terminals were investigated following experimental 'closed-space' subarachnoid haemorrhage (SAH) in cat. The left middle cerebral artery (L-MCA) was compared to the ruptured right (R-MCA) one. Permeability kinetics of 3H-NA (noradrenaline) were measured simultaneously in isolated segments of paired R- and L-MCAs, testing responses to electrical field stimulation and the presence of the alpha-adrenoceptor antagonist, phentolamine, at different concentrations and times post-SAH. Fractional 3H-NA efflux from ruptured R-MCAs was reduced to undetectable levels at 18 h to at least 3 d post-SAH. Response to electrical stimulation partially recovered at 10 d and approached the controls by 16 to 30 d. In the L-MCAs, 3H-NA efflux was decreased up to 90% at 18 h, but recovered to control level by 3 d, unless it too became involved by encroachment of blood from the SAH side. The fractional 3H-NA efflux in the controls was typically augmented by phentolamine, reaching a peak at 0.3 microM of the drug. This overflow response was completely lost between 0.03 and 3.0 microM phentolamine in the R-MCAs for at least 30 d post-SAH, whereas uninvolved L-MCAs regained drug-induced overflow at 10 to 16 d post-SAH. Uptake of 3H-NA after SAH was also decreased 30 to 50% for both MCAs at 18 h and 3 d post-SAH. Control 3H-NA uptake was regained by 10 d post-SAH in the L-MCA but not until 16 d in the R-MCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Neonatal anatomical correction of transposition of the great arteries: non-invasive assessment of haemodynamic function up to four years after operation.

Intracardiac and great artery blood flow velocities were recorded by pulsed and continuous wave Doppler ultrasound in 18 children aged between eight months and four years (mean 25 months) who had undergone anatomical correction of transposition of the great arteries in the first month of life. Postoperative peak flow velocities across the mitral valve and in the ascending aorta were not significantly different from those in an age matched control population, but tricuspid flow velocities were higher than normal. Aortic regurgitation was detected in only one of the eighteen patients, a markedly lower frequency than that reported after two stage anatomical correction. Peak velocities in the pulmonary artery were higher than normal, and in most cases there was some degree of stenosis of the pulmonary artery at the site of anastomosis.

Aorta↗
PubMed1988

Infective endarteritis affecting the left pulmonary artery after anatomical correction of complete transposition of the great arteries.

Clinical features of infective endocarditis developed in a two year old boy. He had successfully undergone anatomical correction of complete transposition of the great arteries during the neonatal period. At routine investigation one year later he showed evidence of important supravalvar pulmonary stenosis. He remained symptom free until endocarditis developed. Streptococcus pneumoniae was isolated from serial blood cultures. Despite prompt treatment with specific intravenous antibiotic treatment the patient died of overwhelming sepsis. At necropsy the stenosed portion of the left pulmonary artery was seen to be the site of infection.

Arterial Occlusive Diseases↗
PubMed1988

Accumulation of intimal platelets in cerebral arteries following experimental subarachnoid hemorrhage in cats.

From 2 hours to 23 days following experimental subarachnoid hemorrhage, the accumulation of indium-111-labeled platelets on the intimal surface of the middle cerebral artery was studied in 23 cats. Subarachnoid hemorrhage was produced by transorbital rupture of the right middle cerebral artery. Of the 23 cats, 17 exhibited right middle cerebral artery/left middle cerebral artery radioactivity ratios of greater than 1.25. When these results were compared with those of 12 control cats, 0.001 less than p less than 0.005 (chi2 test). Thus, the results from the control and experimental groups are significantly different and indicate early (after 2 hours) preferential accumulation of intimal platelets in the ruptured right middle cerebral artery compared with the unruptured left middle cerebral artery and new platelet deposition continuing for up to 23 days. However, the experimental group did not reveal a clear pattern for platelet accumulation following subarachnoid hemorrhage. There was no simple correlation between the magnitude of the radioactivity ratios and the time after hemorrhage when the cats were killed although the ratios for 2 hours to 7 days seemed greater than those for 8 to 23 days. Assuming the pivotal role of platelets in the angiopathy of subarachnoid hemorrhage, the administration of antiplatelet agents as soon as possible following its occurrence may be of value.

Animals↗
PubMed1988

Petrosal approach for petroclival meningiomas.

Thirteen patients harboring large petroclival meningiomas are reported. The evolution of the petrosal approach is discussed, and modifications for improvement in surgical technique are described. There was no mortality in this series, and total removal was achieved in all but two patients. Morbidity included cranial nerve deficit, pulmonary embolism, and hemiparesis.

Adult↗
PubMed1988

Myelopathic cervical spondylotic lesions demonstrated by magnetic resonance imaging.

Eighteen cases are presented in which magnetic resonance (MR) imaging demonstrated two types of lesions in patients with cervical spondylotic myelopathy. In the first type, localized spinal cord changes at the level of compression, consistent with myelomalacia, were revealed best with T2-weighted images as high-intensity spinal cord signals. In the second type, lesions consistent with either cystic necrosis or secondary syrinx were noted locally, and/or extending longitudinally up, and/or down inside the spinal cord. These latter lesions were best revealed as low-intensity signals on T1-weighted MR images and as a signal-void sign (moving fluid) on proton-density or T2-weighted MR images. It is suggested that segmental lesions at the level of the spondylotic bar represent early proton changes from pressure in and around the same zones that evolve into gray-matter enhancement regions shown as "snake-eyes" on delayed computerized tomography (CT) after myelography. The longitudinal lesions are thought to be the same pencil-shaped zones of cystic necrosis evolving into a secondary syrinx in the late stages (and usually found in the anterior portion of the dorsal columns during delayed CT after myelography). As spinal MR imaging continues to improve, these lesions will be demonstrated more clearly within the cord substance.

Adult↗
PubMed1987

Iliopsoas hypertrophy mimicking acute abdomen in a bodybuilder.

Marked hypertrophy of the psoas muscle in a bodybuilder produced a unilateral extrinsic mass effect upon the medial cecum and adjacent small bowel. The patient had presented with right lower quadrant pain and leukocytosis. Routine contrast studies of the abdomen were misleading, but a computed tomogram suggested the correct diagnosis.

Abdomen, Acute↗
PubMed1987

A combined infratemporal and posterior fossa approach for the removal of giant glomus tumors and chondrosarcomas.

Giant glomus jugulare tumors with a large posterior fossa extension are considered either inoperable or at least requiring of a two-stage operation. Likewise, the surgical approach and treatment for chondrosarcomas of the temporal bone are controversial. We describe a combined approach in which, with the aid of microsurgical and laser techniques, such tumors can be removed in one stage. The surgical approach involves a lateral infratemporal approach combined with a posterior fossa craniectomy. This technique was used in seven cases: five glomus jugulare tumors and two chondrosarcomas. There were no deaths, and surgical morbidity consisted of weakness in the facial nerve in four of these patients and gastrointestinal hemorrhage and respiratory distress syndrome in one patient.

Brain Neoplasms↗
PubMed1987

Hyperbaric oxygen and cerebral infarction in the gerbil.

The effectiveness of hyperbaric oxygen in reducing the incidence of cerebral infarction during the first 36 hours after occlusion of the right common carotid artery was investigated in gerbils. After carotid ligation, the gerbils were divided into four groups: controls, which breathed air at ambient pressure; group 1, which received hyperbaric oxygen at 1.5 atmospheres absolute pressure (ATA) for 36 hours, with a 5-minute, 1.5-ATA air break each hour; group 2, which received hyperbaric oxygen at 1.5 ATA for 1 hour alternating with 1 hour air at 1 ATA, for 36 hours; and group 3, which received hyperbaric oxygen at 1.5 ATA with hourly 5-minute air breaks for 18 hours, and ambient air for the second 18 hours. Neurological evaluations and staining of the brain with tetrazolium revealed the following results at 36 hours after carotid ligation: 72% of the controls had cerebral infarcts; 26% of the gerbils in group 1 had infarcts, but all animals died at 24-36 hours after beginning hyperbaric oxygen exposure from oxygen toxicity; 44% of the gerbils in group 2 had infarcts; 11% of the gerbils in group 3 had infarcts during the first 18 hours after carotid ligation, and no infarcts developed in the 18 hours that followed. Hyperbaric oxygen reduces the incidence of cerebral infarction after carotid artery ligation, presumably by allowing time for collateral circulation to develop.

Animals↗
PubMed1987

Computed tomography in neuronal ceroid lipofuscinosis: four case reports.

The computed tomography findings are discussed in four cases of neuronal ceroid lipofuscinosis. When this severely progressive inherited disease of lipid metabolism is suspected, confirmation may be obtained with electron microscopy of peripheral lymphocytes and certain tissues. Some physiologic-pathologic features are discussed.

Adult↗
PubMed1987

Constrictive structural elements in human cerebral arteries following aneurysmal subarachnoid haemorrhage.

Histoimmunological, histochemical, and histological studies were conducted on cerebral arteries from four living patients with a recent aneurysmal subarachnoid haemorrhage. There appeared to be a correlation between the severity of vasospasm and the magnitude of pathological findings. Large myofibroblast cells and type V collagen within the medial layer were abundant in arteries showing marked vasospasm, but were less conspicuous in those showing milder involvement. Intracranial arteries from patients who died from non-cerebral causes did not demonstrate these changes. In ruptured vessels, there was also a positive fluorescence for actin-myosin filaments in layers of the arterial wall other than the media. It is postulated that the intimal and adventitial actin-myosin, myofibroblasts and type V collagen may contribute to cerebral vasospasm by holding the damaged vessel in a contracted phase during the healing period.

Adult↗
PubMed1987

The relationship between columnar epithelial dysplasia and invasive adenocarcinoma arising in Barrett's esophagus.

The authors assessed the relationship between dysplasia in Barrett's esophagus and invasive adenocarcinoma in a study of both endoscopic biopsy specimens and esophagectomy specimens. They reviewed the pathologic findings and clinical follow-up of 14 patients with dysplasia in Barrett's mucosa in endoscopic biopsy specimens. They also studied systematically the histopathologic features of the Barrett's mucosa in 43 esophagectomy specimens resected for Barrett's carcinoma. In the biopsy specimens, dysplasia occurred in distinctive-type Barrett's mucosa of 13 patients (93%) but in cardiac-type mucosa of only 3 (21%). Six patients had high-grade dysplasia; five underwent esophagectomy and three of these were found to have superficially invasive adenocarcinoma. The other patient with high-grade dysplasia as well as eight patients with intermediate- or low-grade dysplasia are not known to have carcinoma on available follow-up. In the study of resection specimens, high-grade dysplasia was strongly associated with adjoining invasive adenocarcinoma, because 84% of areas with invasion had high-grade dysplasia and 92% of areas with high-grade dysplasia showed invasion. The authors' findings suggest that the dysplasia-carcinoma sequence most commonly occurs in Barrett's mucosa of the distinctive type; high-grade dysplasia in Barrett's mucosa is a marker indicating high probability of invasive carcinoma; the presence of high-grade dysplasia in biopsy specimens of Barrett's mucosa is an indication for esophagectomy in suitable surgical candidates.

Adenocarcinoma↗
PubMed1987

Optic nerve avulsion secondary to traumatic enucleation.

Optic nerve injuries may be associated with craniofacial trauma. Actual avulsion of the optic nerve secondary to traumatic enucleation, however, is a unique injury that has secondary neurosurgical complications. Two cases of such an injury are presented.

Adolescent↗