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Biomedical subjects

D C Snover

Publications and source records attributed to D C Snover.

At least 91 records · Page 5Linked to original sources

The plain abdominal radiograph in acute gastrointestinal graft-vs.-host disease.

The plain abdominal radiographs of 28 patients with acute gastrointestinal graft-vs.-host disease (GVHD) were examined to determine the plain radiographic findings associated with this disorder. These findings, in order of decreasing frequency, included air-fluid levels, bowel wall/mucosal fold thickening, gasless abdomen, bowel dilatation, pneumatosis intestinalis, and ascites. When a number of these findings are present, the plain abdominal radiographs may be sufficiently characteristic to suggest gastrointestinal GVHD. Differentiating acute gastrointestinal GVHD from small-bowel obstruction is often of major clinical importance. Fortunately, the bowel gas pattern in acute gastrointestinal GVHD rarely suggests obstruction and, thus, bowel obstruction can usually be excluded on the basis of plain radiographs alone.

Bone Marrow Transplantation↗

Benign epithelial polyps of the stomach.

It is clear that benign gastric epithelial polyps form a heterogeneous group with distinct pathologic features. Variability exists in regard to malignant potential and association with various polyposis syndromes. The most important aspects of these lesions are as follows: The only gastric polyps with a direct malignant potential are the neoplastic polyps. Since these lesions are most commonly solitary and antral, and such lesion identified at endoscopy or radiographically should be removed. The hyperplastic polyps, the most common of gastric polyps, are frequently associated with carcinoma, but probably do not have any malignant potential over and above that of the atrophic gastritis which usually accompanies them. Fundic-gland hyperplasia, a poorly recognized but common entity, carries no malignant potential. The diagnosis of FGH should be suspected in cases where the fundus and body of the stomach are carpeted with sessile 1 to 5 mm polyps. Since these lesions may spontaneously regress, no therapy is needed other than biopsy to confirm the diagnosis. However, because of the association with familial polyposis and Gardner's syndrome, patients with FGH should be evaluated for the possibility of one of these syndromes. Since in some cases several types of polyps may occur in the same stomach, it may be necessary to biopsy several in order to be sure a neoplastic polyp is not present. In cases of multiple gastric polyposis in which variability of gross appearance is noted, polyps of several types should be biopsied. Since the neoplastic polyps tend to be larger, pedunculated, and antral in location, lesions with these characteristics should be removed.

Adenoma↗

Atypical lipomas of the colon. Report of two cases with pseudomalignant features.

Two cases of large intestinal submucosal lipomas with atypical features are described. These atypical features consist of cellular fibrosis, atypical hyperchromatic nuclei, and increased mitotic activity, with the occasional presence of atypical mitoses. They were associated with ulceration and appeared to be reactive in nature. The major importance lies in distinguishing these lesions from truly sarcomatous tumors.

Colonic Neoplasms↗

Invasive Fusarium infections in bone marrow transplant recipients.

From November 1982 to September 1983, three cases of invasive infection due to Fusarium species were documented in bone marrow transplant recipients. Fusarium was cultured from discrete skin nodules (one patient), maxillary sinus (one patient), or from the blood and surgically excised nasal septum (one patient). All three isolates were resistant to 5-fluorocytosine, whereas only one isolate was resistant to amphotericin B. Although all three patients died, two of the patients had clearing of their Fusarium infection. From this experience and from a review of the literature, it is concluded that despite the dismal prognosis for immunocompromised patients with Fusarium, beneficial therapies would include systemic amphotericin B, local surgical resection, and possibly leukocyte transfusions.

Adolescent↗

Suppression of weight gain by glucagon in obese Zucker rats.

Glucagon has been shown to lower blood lipids and to decrease food intake and body weight in short-term studies in man and animals. There is evidence of decreased secretion of glucagon in human obesity. The Zucker obese rat suffers from a genetic type of obesity and has an absolute reduction in circulating glucagon concentration. The effect of long-term administration of glucagon on the body weight in obese Zucker rats was studied. Glucagon caused a marked (-20%) reduction of body weight in obese Zucker rats with no change in feed intake. Urine glucose, urea nitrogen, creatinine, and ketone content, as well as serum triglyceride, cholesterol, alkaline phosphatase, creatinine, and insulin levels remained unchanged. Weights of perirenal fat, kidneys, and heart also remained unchanged. However, glucagon injection in obese Zucker rats caused significant decrease in serum glucose, and increases in SGOT, liver weight, and liver lipid and glycogen content. Further investigations are needed concerning the safety of chronic glucagon administration for weight control.

Adipose Tissue↗

Piecemeal snare excision of large sessile colon and rectal polyps: is it adequate?

This study analyzes 28 consecutive patients with large sessile polyps snared piecemeal from the colon and rectum. The sections were examined to determine the adequacy of orientation and margin of excision. Orientation was judged excellent in five, good in 12, fair in six, and poor in five cases. The margin of excision was judged adequate in 23 of 28 cases. Five of eight patients with invasive carcinoma underwent bowel resection, and no residual tumor was found in the resected specimens. Of the remaining 20 patients without carcinoma, five had residual tumor or recurrences, with follow-up from 6 months to 6 years (average, 18 months). All of them underwent rebiopsies and electrocoagulation. None of the residual tumor or recurrences showed evidence of malignancy. Piecemeal snare excision of large sessile polyps of the large bowel appears to be an adequate procedure for most patients. A close follow-up with colonoscopy or proctoscopy is essential because residual tumor or recurrences are common.

Colonic Polyps↗

Colorectal polyps in Cowden's disease (multiple hamartoma syndrome).

Colorectal polyps are described in five patients with Cowden's disease. A brother-sister kindred and two unrelated patients had multiple colonic polyps 0.1-0.4 cm in diameter. Microscopical examination of seven polyps removed from these four patients showed distinctive lesions which were probably hamartomatous, and characterized by disorganization and proliferation of the muscularis mucosae with minimally abnormal overlying mucosa. The fifth patient had a solitary 2-cm epitheloid leiomyoma resected from the rectum. Review of all cases of Cowden's disease in the English literature suggests that gastrointestinal polyposis may be a frequent finding if it is specifically searched for. It does not appear that the previously reported association of Cowden's disease with gastrointestinal cancer is valid. The discovery of multiple colonic polyps 0.1-0.4 cm is diameter with a rectosigmoid distribution and a hamartomatous microscopical appearance is characteristic of Cowden's disease. Cowden's disease should be included in the differential diagnosis of gastrointestinal polyposis states.

Adult↗

Acute necrotising eosinophilic myocarditis.

Löffler's endocarditis is a recognised complication of diseases associated with eosinophilia. Eosinophilic heart disease is usually chronic, but there is a rare acute variety. Three patients with an unusual form of eosinophilic heart disease characterised by acute necrotising eosinophilic myocarditis after a possible initial viral infection and underlying allergic diathesis are reported. In contrast to previously reported cases of acute Löffler's endocarditis there was no notable extracardiac pathology.

Acute Disease↗

Sonography of the gallbladder in bone marrow transplant patients.

Nonshadowing opacities in the gallbladder (sludge) occurred in nine of 44 bone marrow transplant patients as a nonspecific finding. Sludge occurring within 2 wk of bone marrow transplant was transient. Later, sludge accompanied hepatic graft versus host disease in seven of 10 patients with this complication of bone marrow transplant. During the course of graft versus host disease, disappearance of sludge matched clinical improvement. Persistence of sludge in patients with hepatic graft versus host disease was associated with a poor prognosis. The gallbladder of one patient who underwent cholecystectomy exhibited histopathologic findings of graft versus host disease.

Adolescent↗

Aspergillosis in 25 renal transplant patients. Epidemiology, clinical presentation, diagnosis, and management.

In immunocompromised renal transplant patients, aspergillosis can be a life-threatening opportunistic infection. During an 8-year period, 25 renal transplant recipients at the University of Minnesota Hospitals developed unequivocal invasive aspergillosis that occurred in epidemic-like patterns in immunocompromised patients throughout the hospital. The premortem diagnosis was made in only 14 of the 25 patients. Seventeen patients died, and three of the eight survivors lost their allografts. The prognosis was dependent upon the clinical pattern of illness: three clinical patterns emerged: (1) cavitary lung disease, (2) diffuse pulmonary disease, and (3) central nervous system disease. All patients in the latter two categories died. The best results were with those patients treated with both amphotericin B and excision of cavitary lung lesions. All three patients treated in this manner survived with functioning grafts. Traditionally, sputum cultures have been thought to be unreliable because Aspergillus is a common colonizer of the upper respiratory tract and a contaminant in laboratories. In this study, false positive sputum cultures were common. A positive sputum culture can be helpful, however, all patients with two positive sputum cultures proved to have invasive aspergillosis. In addition, 86% of patients with positive sputum cultures who were clinically ill proved to have invasive infection. Bronchoscopy is a useful technique to follow up a positive sputum culture or investigate negative sputum cultures with typical clinical patterns. Routine bronchoscopy, unfortunately, also yields a high incidence of false positive cultures. Since the use of covered brush bronchoscopy technique, however, no false positive transbronchial cultures have been found. Transbronchial biopsy is a useful adjunct and is proof of the presence of invasive disease when the results are positive. However, false negative results are also found. Overall, the highest diagnostic yield is obtained both with transbronchial lung biopsy and covered brush bronchoscopy culture. All eight patients with both these procedures were correctly identified as having invasive pulmonary aspergillosis.

Adult↗

Liposarcoma. A review of factors influencing prognosis.

Tumors of adipose differentiation demonstrate considerable histologic variability as well as a wide variation in behavior patterns. A variety of clinical, gross, and microscopic features are useful in predicting behavior. Unfortunately, a number of different classification systems for liposarcoma with confusing nomenclature appear in the literature. This paper reviews general features affecting prognosis and presents a summary of the major classification systems. A subclassification of tumors into three grades (high, intermediate, and low) is suggested, based on potential for malignant behavior. Our system of grading may be used to guide the surgeon in the course of therapy. In light of the potential for confusion in identification and classification, good communication between surgeon and pathologist is essential to choice of appropriate therapy and ensuing chances for recurrence or survival.

Humans↗

Variability of histologic pattern in recurrent soft tissue sarcomas originally diagnosed as liposarcoma.

The histopathologic classification of liposarcoma and its clinicopathologic significance are well delineated in previous studies, but the literature is inexplicably mute on recurrent liposarcomas. Supposition and experience may have led to the assumption that the microscopic features remained static over a period of years and multiple recurrences. Thirteen sarcomas originally classified as liposarcoma were reviewed to assess patterns of histologic change with recurrence. A total of 52 recurrences was studied. In 7 of the 13 cases, multiple morphologic sarcomatous patterns were identified, either as a change with recurrence or as multiple discrete patterns within a tumor. All changes except in one case occurred before irradiation or chemotherapy. The variations included patterns such as malignant fibrous histiocytoma, hemangiopericytoma, malignant schwannoma, and unclassified spindle-cell sarcoma as well as the various liposarcoma subtypes. This variability of patterns can cause significant diagnostic difficulties and can cause one to question the validity of using monomorphic diagnoses in all cases. In addition, the polymorphic differentiation of these tumors supports the concept that soft tissue sarcomas are derived from a pluripotential mesenchymal stem cell.

Adult↗

Thymic carcinoma. Five distinctive histological variants.

Five histologically distinct variants of thymic carcinoma are described: mixed small cell undifferentiated squamous cell carcinoma (three cases), basaloid carcinoma (two cases), mucoepidermoid carcinoma (one case), clear cell carcinoma (one case), and sarcomatoid carcinoma (one case). While forming a heterogeneous group, these tumors bear the common features of an anterior mediastinal location and lack of evidence of a primary tumor elsewhere, marking them as primary thymic neoplasms. All except the sarcomatoid variant are morphologically related to similar malignant neoplasms of other organs. These tumors should be recognized as morphological variants of primary thymic carcinoma and demonstrate the ability of thymic epithelium to differentiate toward a variety of different cell types.

Adenocarcinoma↗

Wiskott-Aldrich syndrome: histopathologic findings in the lymph nodes and spleens of 15 patients.

Seventeen lymph nodes and 13 spleens from 15 patients with the Wiskott-Aldrich syndrome were examined histologically. The material included both biopsy and autopsy specimens. Consistent findings included depletion of small lymphocytes from T cell areas (all cases), prominence of the reticulum cell stroma (all cases), the presence of atypical plasma cells with and without plasmacytosis (16 lymph nodes and 11 spleens), and extramedullary hematopoiesis (13 lymph nodes and 9 spleens). Less frequent features noted were tissue eosinophilia, hemophagocytosis, focal fibrosis, and progressive depletion of germinal centers. One case with a unique abundance of transformed lymphocytes is described.

Child↗