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Biomedical subjects

R R Smith

Publications and source records attributed to R R Smith.

At least 127 records · Page 7Linked to original sources
PubMed1986

Intracisternal blood injections fail to produce cerebral angiopathy in cats.

Adult cats were subjected to subarachnoid hemorrhage by three repeated intracisternal injections of autogenous nonheparinized blood (2 ml/injection) at weekly intervals. Histological studies (light and electron microscope) were made of the basilar artery and the middle cerebral arteries of all animals. In the subarachnoid-injected hemorrhaged animals, a large, organized blood clot extended uninterrupted along the lateral and ventral aspect of the medulla and pons, covering or partially encircling the basilar artery for most of its course. Smaller and less organized clots extended into various mesencephalic regions. Histologic findings in vessels from the injected hemorrhaged group were similar to those of control animals, showing neither evidence of endothelial damage, intimal proliferation, nor other significant vascular changes. The results suggest that the injection of blood into the subarachnoid space does not produce significant structural changes, but that the primary stimulus for the initiation of such pathologic events is closely tied to vessel rupture.

Animals↗
PubMed1986

Computed tomography evolution of multicystic encephalomalacia.

A case of multicystic encephalomalacia is presented, demonstrating postischemic maldevelopment in the cerebrum on serial computed tomography scans. The developmental features of multicystic encephalomalacia are discussed, as well as migration abnormalities such as encephaloclastic porencephaly and agenetic porencephaly. Representative computed tomography scans of porencephaly are included.

Brain↗
PubMed1986

Schneiderian papillomas: a clinicopathologic study of 67 cases.

The clinical and pathologic features of schneiderian papillomas were studied in 67 patients. There were 40 male and 27 female patients, and the mean age at diagnosis was 49 +/- 17.9 (SD) years. Nasal obstruction or perception of a nasal mass was the most common presenting symptom; mean duration of symptoms was 10.8 +/- 15.8 (SD) months. Almost equal numbers of papillomas had predominantly endophytic (inverted) (n = 32) and predominantly exophytic (fungiform) (n = 30) patterns, and five had mixed patterns. Multiple morphologic variables were evaluated in the initial specimens, including cytologic atypia and number of mitotic figures; there were no statistically significant correlations between these variables and biologic behavior. Of the 39 patients for whom follow-up information was available (mean follow-up period, 38.6 months), six patients (all with predominantly endophytic patterns) had copresented with schneiderian papillomas and carcinomas. The remaining 33 patients initially had only benign schneiderian papillomas. In these 33 patients, recurrences developed in 11 (33 per cent), local invasion in two (6 per cent) (both with inverted papillomas), and epidermoid carcinoma in one (3 per cent) (with an inverted papilloma). Three patients had evidence of disease when last examined, and two patients had died of disease (both after copresentation with schneiderian papillomas and carcinomas). The continued use of the term inverted papilloma (endophytic pattern) as a specific subset of schneiderian papillomas is recommended, as all serious complications, including progression to local invasion, copresentation with carcinoma, and development of carcinoma, were associated with these lesions.

Adult↗
PubMed1986

Doppler echocardiography after anatomical correction of transposition of the great arteries.

Nineteen patients who had anatomical correction of transposition of the great arteries between the ages of one week and 10 years were investigated by pulsed and continuous wave Doppler echocardiography 1-98 months after operation. Peak blood flow velocities across the atrioventricular valves were significantly higher than normal, but no pathological regurgitation was seen. Systolic aortic velocities were normal in all but one patient, but mild aortic regurgitation was detected in ten. Increased flow velocities either at pulmonary valve level, at the pulmonary artery bifurcation, or in the left pulmonary artery were detected in 14 patients, the maximum calculated pressure drop being 36 mm Hg. Adequate Doppler sampling of the right pulmonary artery was not achieved in any of the cases, and sampling of the left pulmonary artery was possible in only ten. The principal limitation of the Doppler ultrasound method in this study was the inability to obtain flow velocities from the branch pulmonary arteries in most patients. Doppler echocardiography provides valuable information after the arterial switch operation and may reduce the need for repeat cardiac catheterisation.

Aortic Valve↗
PubMed1986

Exertional rhabdomyolysis associated with decerebrate posturing.

A case is presented in which decerebrate posturing after a head injury led to rhabdomyolysis and renal failure. Exertional rhabdomyolysis is caused by an energy deficient state in overworked musculature that leads to a loss of integrity of the muscle cell. The resultant myoglobin in serum leads to acute renal failure. This condition should be suspected in a comatose patient with fever, brown discoloration of the urine, and edema of the extremities. Laboratory results will show orthotoluidine positive urine with a clear serum, elevated serum creatine phosphokinase, and serum creatinine elevation out of proportion to blood urea nitrogen. Management consists of fluids and diuretics with dialysis if necessary. Rhabdomyolysis with head injury and decerebracy may occur more frequently than has been previously reported.

Acute Kidney Injury↗
PubMed1985

Primary mediastinal hemangiopericytoma: computed tomography correlation.

A case of primary mediastinal hemangiopericytoma with computed tomography correlation is presented. Although this is rare cause of mediastinal mass, the diagnosis should be considered when computed tomography of the mass shows contrast medium enhancement, particularly if there is a curvilinear encircling structure suggesting a large feeder vessel.

Aged↗
PubMed1985

Neonatal gonadal stromal tumor of the testis: limitations of tumor markers.

We report case 10 of a gonadal stromal tumor of the testis in a neonate. This tumor may occur in the testis or ovary, and is defined as a tumor of any of the specialized supporting structures of the male or female gonad. All neonatal tumors reported to date have been benign. The serum alpha-fetoprotein level, although elevated for adults, was within the normal range for an infant.

Humans↗
PubMed1985

Neuroectodermal neoplasms arising in congenital nevi.

Congenital giant nevi of neuroectodermal origin are composed predominantly of melanocytes and occasional neural elements. Neoplasms arising in such nevi may be morphologically heterogeneous with variable clinical behavior. We report the case of a female infant born with multiple pigmented nevi, including a giant hairy nevus of bathing trunk distribution in which arose a large pedunculated mass involving the sacral region, buttocks, perineum, and left thigh. Within this neoplasm, mixtures of neural crest-derived tissues having both melanocytic (nevus) cell and neural supportive (neuroid of Schwannian) cell differentiation were identified. The neural differentiation, which was seen in the dermis and subcutaneous tissue, had a neurofibromatous appearance and demonstrated multiple pseudomeissnerian corpuscles. In addition, at 16 months of age the child developed a malignant melanoma in the flank region of this congenital giant nevus. The morphologic pluripotentiality of the primitive neural crest derivatives in congenital nevi has only recently been elucidated. These lesions should be regarded as neuroectodermal neoplasms and subclassified according to their differentiating histologic characteristics because prognosis and management are influenced by morphologic determinants.

Buttocks↗
PubMed1985

Marrow cell necrosis in anorexia nervosa and involuntary starvation.

Marrow specimens from six patients with anorexia nervosa and three with involuntary starvation were examined for the presence of gelatinous transformation and marrow cell necrosis. Five of the patients had pancytopenia. Acanthocytes were present in the circulation of all nine. In only two patients was marrow cellularity adequate. Gelatinous transformation was present in every marrow specimen and was of a marked degree in eight. Marrow cell necrosis was identified in all nine marrow specimens. The necrosis was extensive in one specimen, focal in the others and limited to the areas of gelatinous transformation. Severe malnutrition was the single element common to all the patients.

Acanthocytes↗
PubMed1985

Interleukin 3 promotes the in vitro proliferation of murine pluripotent hematopoietic stem cells.

Medium conditioned by activated T lymphocytes stimulates the in vitro proliferation of pluripotent hematopoietic stem cells (spleen colony-forming units [CFU-S]) but the factors involved have not been identified. Because the lymphokine interleukin 3 (IL-3) enhances in vitro colony formation by committed hematopoietic progenitor cells, we examined the effect of IL-3 on the in vitro proliferation of CFU-S using an 11-d spleen colony assay. When mouse marrow cells were placed in liquid culture, CFU-S content declined progressively and by 96 h only 13% of the CFU-S remained. By contrast, after 96 h in the presence of 20 U/ml of IL-3, the number of CFU-S were the same as that in the initial inoculum. Although the number of CFU-S eventually declined, they could still be recovered after 264 h of culture. In the absence of IL-3, the number of CFU-S synthesizing DNA was negligible; in its presence, greater than 20% of the CFU-S were in cycle. IL-3 stimulated CFU-S proliferation at a concentration of 0.2 U/ml. The dose-response curve was similar to that observed for other biologic effects of the lymphokine, and as little as 1 h of exposure to IL-3 enhanced the survival of CFU-S in vitro. Treatment of marrow cells with anti-Thy 1.2 antibody and complement before exposure to IL-3 did not inhibit spleen colony formation, but treatment of the cells with anti-Thy 1.2 antibody and complement after exposure to IL-3 reduced CFU-S recovery after 96 h of culture by 45%. The cell composition of day 11 spleen colonies formed by IL-3-treated marrow cells was similar to that of colonies formed by untreated marrow cells. Finally, day 11 CFU-S persisting in the marrow of mice treated with 5-fluorouracil required IL-3 for proliferation in vitro. Taken together, these data indicate that IL-3 promotes the proliferation of CFU-S in vitro, increases the number of CFU-S synthesizing DNA, but does not alter their commitment program, and the target cell population includes CFU-S with self-renewal and marrow-repopulating ability.

Animals↗
PubMed1985

Arterial wall changes in early human vasospasm.

Histological, histochemical, and histoimmunological studies were conducted on cerebral arteries from three living patients with a recent subarachnoid hemorrhage. There seemed to be a correlation between the severity of vasospasm and the magnitude of pathological alterations. Myofibroblasts and Type V collagen within the medial layer were abundant in vessels showing marked constriction, but were less conspicuous in those arteries showing milder involvement. Intracranial arteries from patients who died from noncerebral causes did not demonstrate these changes. Thus, myofibroblasts and Type V collagen may be related to cerebral vasospasm by holding the damaged vessel in a contracted phase for weeks during the healing period.

Adult↗
PubMed1985

Malignant transformation in non-irradiated recurrent respiratory papillomatosis.

The clinical, radiographic and post mortem findings occurring in a 6-year-old female with a four-year history of recurrent respiratory papillomatosis (RRP) are described. At autopsy, there were two separate foci of malignant transformation (malignant degeneration) in the bronchioloalveolar papillomata. This patient is the youngest in whom such changes have been described. Malignant transformation is a rare occurrence and is usually seen in older patients with longstanding papillomatosis, therapeutic irradiation, or a history of smoking. Pulmonary spread represents the majority of cases with "spontaneous" malignant transformation.

Age Factors↗
PubMed1985

Heparin reduces proliferative angiopathy following subarachnoid hemorrhage in cats.

Subarachnoid hemorrhage (SAH) was produced in cats by transorbital rupture of the right middle cerebral artery (MCA). In untreated cats, widespread proliferative angiopathy occurred in both MCA's by 16 days after SAH. In cats that received systemic heparin, the pathological events following SAH were clearly reduced in the ruptured artery, and were not present in the contralateral left MCA. Platelets are known to adhere to the subintimal surface of cerebral arteries after SAH. The authors suggest that platelet-derived growth factor released from the intimal platelet carpet following SAH may be the stimulus for the development of proliferative angiopathy, and that this platelet factor is inhibited by heparin.

Animals↗
PubMed1985

Traumatic decerebracy with preserved consciousness and voluntary movement.

Decerebrate rigidity is a frequent occurrence in cases of craniocerebral trauma. It is almost always accompanied by coma and usually denotes a poor prognosis. Primary focal brain stem lesions due to trauma are uncommon and may be accompanied by other diffuse cerebral lesions. This report reviews the anatomical basis and clinical findings of a unilateral brain stem lesion in a patient with traumatic decerebracy and preserved consciousness. The anatomical pathways and possible physiological mechanism are discussed, and a few comments on the prognosis of such lesions are given.

Adult↗
PubMed1985

Carcinoma arising in Barrett's esophagus.

Between 1951 and 1983, 32 patients who had adenocarcinoma develop in Barrett's esophagus were identified at our institution. Twenty-nine patients were male (91 per cent) and 29 were white. Amongst the 23 patients in whom the relevant data were available, 78 per cent admitted to regular alcohol intake and 78 per cent smoked. Only one of these patients did not smoke or drink alcohol. Surprisingly, only 61 per cent of the patients had symptoms suggestive of gastroesophageal reflux and reflux was demonstrated roentgenographically in only 41 per cent. Twenty-one of the patients underwent esophagogastrectomy. Life table analysis revealed a survival rate of 34 per cent at two years and 14.8 per cent at five years.

Adenocarcinoma↗
PubMed1984

The spectrum of carcinoma arising in Barrett's esophagus. A clinicopathologic study of 26 patients.

The clinical and pathologic features of carcinoma arising in Barrett's esophagus were studied in resection specimens from 26 patients. White males predominated (73%). A history of symptomatic gastroesophageal reflux was frequently absent, being elicited in only eight of 14 patients (57%) with a carefully obtained history at the time of presentation with carcinoma. Survival was relatively short with a median survival of 23 +/- 5 months, and only three patients had a disease-free survival longer than 2 years. A pathologic spectrum of carcinoma was found: differentiation ranged from well to poorly differentiated in the 20 patients with a single adenocarcinoma; two separate carcinomas were found in four patients; and a spectrum of differentiation in a single tumor was found in the other two cases, one an adenocarcinoid tumor and the other an adenosquamous carcinoma. The tumors were generally far advanced, with extension through the esophageal wall in 23 of 26 cases (88%) and metastases to lymph nodes in 17 of 24 cases (71%). Epithelial dysplasia, including carcinoma in situ in some cases, was found in Barrett's mucosa adjacent to the tumor in all 26 patients. Our findings suggest that a surveillance program for dysplasia in patients known to have Barrett's esophagus is warranted in an attempt to improve the outcome. However, the impact of surveillance on the incidence of Barrett's carcinoma may be lessened by its frequent occurrence in patients with asymptomatic gastroesophageal reflux.

Adenocarcinoma↗
PubMed1984

Intracranial vessels lack vasa vasorum.

A micro-corrosion technique was used to demonstrate an extensive vasa vasorum network in extracranial vessels but did not reveal this system in intracranial vessels of comparable size in three species of animals. The absence of a vasa vasorum network in cerebral vessels may result in a higher level of susceptibility to periarterial abnormalities, such as cerebral vasospasm secondary to subarachnoid hemorrhage.

Animals↗