Biomedical subjects

G S Leventon

Publications and source records attributed to G S Leventon.

6 recordsLinked to original sources

PubMed1986

Enhanced recovery of gut-associated lymphoid tissue by infusion of buffy coat cells and gut leukocytes in the murine syngeneic bone marrow transplantation model.

Ways of accelerating recovery of the mucous membrane immune system in lethally irradiated mice following syngeneic bone marrow transplantation were studied over a 35-day period by quantification of jejunal intraepithelial lymphocytes (IELs) and lamina propria plasma cells. Recovery after a low bone marrow dose allowing 100% animal survival (LBM) was compared with a high (five times minimal) dose (HBM), or a minimal dose augmented with equal numbers of buffy coat cells (LBM + BC) or small gut mucosal lymphocytes (LBM + GL). The maximal decline and subsequent peak repopulation of IELs were: LBM, days 7 through 14, peaking suboptimally by day 28; HBM, day 14, peaking suboptimally but higher than LBM by day 35; LBM + BC, days 11 through 14, peaking at control levels by day 35; and LBM + GL, day 7, peaking at control levels by day 28. The IEL decline was most severe with LBM and HBM treatment and least with LBM + GL. All transplant groups experienced maximal plasma cell decline by day 7. LBM had the most severe depletion, and LBM + GL had the least. Recovery to control levels for the LBM, HBM, LBM + BC and LBM + GL groups occurred by days 28, 21, 21, and 14, respectively. In all instances, greater than 95% of the plasma cells were IgA positive.

Animals↗

PubMed1985

Effect of pretreatment with cyclophosphamide on high-dose toxicity of melphalan in mice.

This study was undertaken to evaluate the effect of pretreatment (or priming) with cyclophosphamide (CY) on lethal toxicity of high-dose melphalan (MELPH) in mice. In C57BL/6 X DBA/2 F1 (hereafter called B6D2F1) mice given an injection of a single dose of CY, 50 mg/kg, 1-5 days before MELPH, 20 mg/kg, improved survival was noted in only one of five experiments. Reducing the challenge dose of MELPH to 17 mg/kg did not improve survival consistently. Priming with CY, 50 mg/kg, 3 days before a dose of MELPH, 20 mg/kg, did not improve survival in CBA/J or C57BL/6 mice. These results indicate that CY is an inconsistent priming agent for abrogating high-dose MELPH toxicity in mice. A slightly earlier recovery of regenerating hemopoietic and of jejunal crypt cells was noted in CY-primed B6D2F1 mice given injections of a low dose of MELPH, 15 mg/kg. The occasional improved animal survival noted in CY-primed B6D2F1 mice might be related to this earlier cell recovery.

Animals↗

PubMed1984

Warty dyskeratoma of the oral mucosa. Correlated light and electron microscopic study.

A warty dyskeratoma arising from the palatal mucosa of a 36-year-old man was studied by light and electron microscopy. The ultrastructural features of this lesion were compared with those of the lesions of Darier's disease. Histologic sections showed a keratin-filled depression of the epithelial surface, suprabasal clefting, and acantholytic, dyskeratotic grains and corps ronds. Electron microscopic examination revealed a decrease in the number of intact attachment sites on the surfaces of the epithelial cells adjacent to the suprabasal cleft. Acantholytic grains within the cleft contained dense bands of tonofilaments and were devoid of attachment sites. Corps ronds within the stratum granulosum appeared as dyskeratotic vacuolated cells. Warty dyskeratomas and the lesions of Darier's disease are clinically distinct, but the acantholytic and dyskeratotic cells characteristic of both show many ultrastructural similarities.

Adult↗

PubMed1983

Isolation of murine small bowel intraepithelial lymphocytes.

A method for the preparation of cellular suspensions of the epithelium of murine small bowel for the purpose of isolation and recovery of intraepithelial lymphocytes employing intraluminal hyaluronidase digestion is described. Discontinuous Percoll centrifugation of these suspensions yielded a 76-82% pure population of intraepithelial lymphocytes. Between 1.6 and 4.0 X 10(7) viable intraepithelial lymphocytes were obtained per gram of gut. The isolate contained approximately equal numbers of T, B and null lymphocytes.

Animals↗

PubMed1981

Sarcomatoid squamous cell carcinoma of the mucous membranes of the head and neck: a clinicopathologic study of 20 cases.

Twenty cases of head and neck mucosal squamous cell carcinoma containing a prominent sarcomatoid element were reviewed with special attention to possible prognostic factors. Patients whose tumors invaded muscle, minor salivary or accessory respiratory glands, or bone had very poor survival rates, whereas those whose tumors were superficial and did not extend into any of these structures had excellent survival rates. A history of irradiation to the tumor site and tumor location in the oral cavity rather than the larynx, pharynx, nasal cavity, or nasal-associated structures were associated with invasiveness and thus with poorer survival. Aside from invasion, histologic features and gross configuration were not found to be of significant prognostic importance.

Aged↗

PubMed1981

Squamous odontogenic tumor.

Squamous odontogenic tumors are rare benign neoplasms of the jaws that are thought to originate from remnants of the dental lamina. They have been confused with other lesions composes of nests of squamous epithelium including well-differentiated squamous carcinoma. The clinicopathologic features of two squamous odontogenic tumors are presented. The electron-microscopic appearance of one of these is described, and the 16 previously reported cases are reviewed.

Adolescent↗