David D. Morgan

Hepatitis B vaccination

Alcoholics are at risk to develop hepatitis B infections, chronic active hepatitis, and even hepatoma. Hence, immunization with hepatitis B vaccine is recommended. However, immune abnormalities may coexist which alter their responsiveness to vaccination. This study compares the immune response to this vaccine in controls (group I), alcoholics without overt liver disease (group II), and alcoholics with clinical liver disease (group III). By the seventh month after the initial vaccination, 89% in group I, 70% in group II, and 18% in group III had a response >36 RIA units. The magnitude of the response was significantly different in groups I, II, and III (19,456 vs 8,326 vs 153 RIA units, respectively; P <0.05, group I vs III). In those who did not respond, a significant (P < 0.02) lower helper/inducer (T4)class of lymphocytes was observed as compared to patients who exhibited an adequate response. These observations suggest: (1) that the response to hepatitis B vaccine is a T-cell-dependent event and (2) that in this population, using the existing vaccine, postvaccination evaluations of antibody concentrations are needed before protection against hepatitis B infection can be assumed.

The effects of rate and route of nutrient intake on protein metabolism

Isotopic measurements of protein kinetics are useful for the investigation of metabolic protein disorders during surgical illness. The effects of rate and route (oral vs parenteral) of nutritional substrate intake have not been well defined. Fischer 344 rats were infused with a total parenteral nutrition (TPN) solution at either 25, 100, or 175% of their normal substrate intake or were fed an oral diet ad libitum. After 4 days, [15N]glycine was infused at 0.138 mg 15N/hr for 24 hr. Whole-body protein turnover (WPT), synthesis, and catabolism were determined by 15N urea enrichment. Fractional synthesis rates (FSR) of liver and muscle protein were calculated by analyzing 15N tissue enrichment. WPT (r = 0.93, P less than 0.001) and liver FSR (r = 0.57, P less than 0.01) increased linearly with TPN infusion rates. All rats had protein synthesis rates greater than catabolism rates except for the rats infused with 25% TPN. Although caloric intake was the same in rats fed orally and those infused with 100% TPN, the orally fed rats had faster WPT (P less than 0.001), synthesis (P less than 0.05), catabolism (P less than 0.001), and liver FSR (P less than 0.05) than the TPN rats. Muscle FSR was not significantly affected by either the route of feeding or the TPN infusion rate. In this study, rate and route of substrate intake affected protein kinetics in the whole animal and liver, but not in muscle. Rate and route of nutrient intake need to be carefully specified and controlled during isotopic studies of protein kinetics.

CASE REPORT: Adjuvant Radiotherapy for Gastrointestinal Stromal Tumor of the Rectum

Gastrointestinal stromal tumors (GIST) have been variously described as leiomyomas and schwannomas and represent a benign histopathological entity of presumed smooth muscle origin (1). Although these tumors are considered benign, one large series reported a 16% local recurrence rate and the appearance of distant metastases following surgery (2). Several prognostic factors have been associated with determining the biologic potential of GIST to include size (2), presentation with symptoms (2), location (3), and mitotic index (2, 4, 5). Despite the possibility of local recurrence and the appearance of metastatic foci, these tumors have been treated primarily with conservative or radical excision. To date, there have been no reports of postoperative therapy in the management of GIST. Herein, we present a case report of a patient with a GIST of the rectum, and describe the rationale for postoperative therapy.

INCORPORATION OF THE SPIN TRAP DMPO INTO CULTURED FETAL MOUSE LIVER CELLS

Abstract— The incorporation of four different spin traps into cultured fetal mouse liver cells was investigated using electron spin resonance spectroscopy. The cells were incubated in saline solutions of the traps, washed, and then irradiated in a saline solution containing hydrogen peroxide. The presence of a reproducible ESR signal was taken as evidence of spin trap incorporation. The spin trap DMPO was found to be incorporated, while PBN and 4‐POBN were not. MNP was toxic to the cells.

Analysis and properties of the cytosolic estrogen receptor from rat thymus

The equilibrium association constant, KA, and the number of receptor binding sites, Bmax, that characterize the estrogen receptor present in rat thymus were determined using five different methods of data analysis on binding data obtained using a dextran-coated-charcoal assay. The methods of data analysis consisted of fitting the binding data directly to the hyperbolic binding function, fitting the data to the Lineweaver-Burk, Scatchard, and Woolf transforms of the hyperbolic function, and the direct linear plot method of Eisenthal--Cornish-Bowden. The Woolf and Eisenthal--Cornish-Bowden methods gave identical results indicating that added estradiol caused a decrease in KA (competitive inhibition) and a marked decrease in Bmax (noncompetitive inhibition). The Scatchard analyses gave only a very qualitative indication of this trend, while the Lineweaver-Burk analyses gave no indication of any such systematic trend. The results from the computationally more difficult fits to the hyperbolic binding equation were in agreement with the Woolf and Eisenthal--Cornish-Bowden results. Thus, the cytosolic thymus estrogen receptor from the rat shows both competitive and noncompetitive inhibition in the presence of endogenous or exogenous estradiol.