Enhancement of intestinal absorptive capacity with omental flaps

The ability of pedicled omental flaps to revascularize isolated jejunal segments was determined in the initial phase of this project. These bowel segments were capable of surviving independent of their mesenteric perfusion, and absorptive function was equal to that of controls as measured by D-xylose assays. In the second phase of this research, we studied in 10 dogs the absorptive capacity of isolated jejunal segments with both an intact mesentery and an omental flap sutured to the antimesenteric border compared with controls that were perfused only by the mesentery. Absorption was measured at 1, 2, 5, and 10 weeks after application of the omental flap. Absorptive function was augmented an average of 25.8% at 2 weeks, reaching 67.6% (p < 0.001) at 5 weeks. This result remained consistent at 10 weeks. Laser Doppler and colored microsphere studies were performed during a secondary laparotomy at 10 weeks and revealed 42.3% and 53.5% increases, respectively, in blood flow to bowel segments receiving both mesenteric and omental perfusion. This finding suggested that the augmentation of absorptive function was a result of increased blood flow.     

Detection of benzoquinone adducts to rat liver protein sulfhydryl groups using specific antibodies

Benzoquinone is an electrophilic metabolite of bromobenzene and other simple aromatic compounds of toxicological interest including benzene, phenol, hydroquinone, and acetaminophen. In reacting with proteins benzoquinone shows great selectivity for Michael addition to sulfhydryl groups and formation of S-(2,5-dihydroxyphenyl) protein adducts. To facilitate the specific detection and eventual isolation and identification of such adducted proteins, we prepared an antiserum capable of recognizing hydroquinone moieties by immunizing rabbits with keyhole limpet hemocyanin modified with 3-[2,5-dihydroxyphenyl)thio]propanoyl groups as haptens. The antiserum had a high titer and showed high specificity for hapten in competitive ELISA with hapten analogues. In Western blot experiments the antiserum detected not only synthetically haptenized control proteins but also several proteins from rat liver microsomes that had been incubated in vitro with [14C]bromobenzene. This binding was completely blocked by free hapten, showing that it was hapten-specific. Each of the microsomal protein bands detected in the Western blots also contained radioactivity, but not all radioactive protein bands reacted with antibody. This antiserum should prove useful in exploring the role of protein arylation by benzoquinone in cytotoxic responses to its metabolic precursors.     

Respiratory syncytial virus-infected pulmonary epithelial cells induce eosinophil degranulation by a CD18-mediated mechanism

Respiratory syncytial virus (RSV)-induced bronchiolitis in infants is characterized by wheezing, respiratory distress, and the histologic findings of necrosis and sloughing of airway epithelium. High concentrations of eosinophil cationic protein (ECP), a cytotoxic protein contained in the granules of eosinophils, have been found in the airways of RSV-infected infants. The mechanisms of eosinophil degranulation in vivo remain largely unknown. Since RSV-infected respiratory epithelial cells are a rich source of cytokines with eosinophil-activating properties, our studies were designed to mimic in vitro the interaction between RSV, pulmonary epithelial cells (A549), and eosinophils in the airway mucosa. We report in this work that, in the absence of epithelial cells, neither RSV, in the form of purified virions, nor UV-irradiated culture supernatant of RSV-infected epithelial cells (RSV-CM) induced eosinophil degranulation. On the other hand, eosinophils released significant amount of ECP when cultured with RSV-infected A549 cells. Uninfected A549 cells, which failed to induce eosinophil degranulation, were equally effective in triggering ECP release if they were cultured with eosinophils in the presence of RSV-CM. Although RSV-CM induced the up-regulation of the beta2 integrin CD11b on eosinophils and the expression of ICAM-1 on A549 cells, release of ECP was inhibited significantly by anti-CD18 mAb, but not by anti-ICAM-1 mAb. These results suggest a novel mechanism by which respiratory viruses may trigger the detrimental release of eosinophil granule proteins in the airway mucosa.     

Body condition at parturition and postpartum weight gain influence luteal activity and concentrations of glucose, insulin, and nonesterified fatty acids in plasma of primiparous beef cows

Effects of body condition score (BCS) at parturition and postpartum weight gain on luteal activity and concentrations of glucose, insulin, and NEFA in plasma were evaluated during the breeding season in 242 primiparous beef cows over 3 yr (Y) at three locations (L). At approximately 90 d prepartum, cows were blocked by breed, expected calving date, and BCS and randomly assigned to diets so that cows would calve in BCS of 4, 5, or 6. At calving, cows were blocked by breed, calving date, and BCS and randomly allotted to gain .45 (M) or .90 (H) kg/d, from parturition to the start of breeding (postpartum nutrition; PPN). During the 60-d breeding season, weekly blood samples were obtained from cows, and progesterone, insulin, glucose, and NEFA were quantified. Progesterone concentrations greater than 1 ng/mL for more than 1 wk indicated luteal activity. To determine the possible value of blood constituents as predictors of luteal activity, categorical data analyses were performed. Cows with greater BCS at parturition had greater concentrations of glucose during breeding (P < .07). Similarly, PPN influenced glucose at the beginning of breeding, but the differences were minimal after d 28 (PPN x day; P <.001). Cows with greater BCS at parturition and M-PPN had greater concentrations of insulin during the breeding season (BCS x PPN; P < .02). Cows with a BCS of 6 at parturition had the lowest concentrations of NEFA; however, cows on H-PPN had greater concentrations of NEFA (BCS x PPN; P < .03). Location, BCS, PPN, and day affected luteal activity (P < .002). Location differences in luteal activity were associated with the interval from calving to the start of breeding. In general, a greater percentage of cows with BCS of 5 or 6 at calving had luteal activity by the end of the breeding season. Concentrations of metabolites in blood during breeding were not predictive of luteal activity. We conclude that BCS at parturition and postpartum nutrition influence concentrations of glucose, insulin, and NEFA in blood and the onset of luteal activity in primiparous beef cows.     

Central nervous system cytokine mRNA expression following Theiler''s murine encephalomyelitis virus infection

This paper records the results of an investigation into potentiation and staircase phenomena in rightventricular guinea-pig papillary muscles with particular reference to the sarcoplasmic Ca(2+)-channel. As a tool to isolate the second ('late', 'tonic') component of isoproterenol-induced biphasic contractions ryanodine was used. On the evidence at present available the monophasic ryanodine-resistant component of the twitch represents that portion of the activator calcium which reaches the troponin C directly, that is, not taking the roundabout way through the intracellular storage structures. In order to avoid functional instabilities of the isolated muscle preparation a short-time double rest stimulation programme was used which combines a number of different tests and gives information on (1) the post-rest potentiation, (2) the post-extrasystolic potentiation, (3) the mechanical post-rest recovery, (4) the interval-strength relationship, and (5) the mechanical restitution. The results of the present work show that under the influence of ryanodine (1) the Bowditch staircase, a typical feature of normodynamic mammalian ventricular preparations as well as of hypodynamic frog heart preparations, does not exist, (2) the post-extrasystolic potentiation disappears, (3) the curve reflecting the mechanical restitution, under normal in vitro conditions a monotonically increasing function, becomes biphasic within the relative refractory period, (4) the conspicuous depression of the isometric post-rest contraction for long lasting pauses interrupting the regular pacing rhythm, a typical feature of isolated guinea-pig ventricular tissue, is clearly diminished, and (5) the characteristic curve, reflecting the potentiation of the post-extrasystolic post-rest contraction as a function of the delay time preceding the extrastimulus, becomes displaced to the premature interstimulus interval. The concept of an 'extended 2-calcium-store model' is supported by this work.     

Randomized phase II trial of BCDT [carmustine (BCNU), cisplatin, dacarbazine (DTIC) and tamoxifen] with or without interferon alpha (IFN-alpha) and interleukin (IL-2) in patients with metastatic melanoma

The purpose of this study was to evaluate in a randomized phase II trial the efficacy and toxicity of combination biochemotherapy compared with chemotherapy alone in patients with metastatic melanoma. Sixty-five patients with metastatic melanoma (ECOG performance status 0 or 1) were randomized to receive intravenous BCNU 100 mg m(-2) (day 1, alternate courses), cisplatin 25 mg m(-2) (days 1-3), DTIC 220 mg m(-2) (days 1-3) and oral tamoxifen 40 mg (BCDT regimen) with (n = 35) or without (n = 30) subcutaneous interleukin 2 (IL-2) 18 x 10(6) iu t.d.s. (day - 2), 9 x 10(6) iu b.d. (day - 1 and 0) and interferon 2 alpha (IFN-alpha) 9 MU (days 1-3). Evidence for immune activation was determined by flow cytometric analysis of peripheral blood lymphocytes. Treatment was repeated every 4 weeks up to six courses depending on response. The overall response rate of BCDT with IL-2/IFN-alpha was 23% [95% confidence interval (CI) 10-40%] with one complete response (CR) and seven partial responses (PR), and for BCDT alone 27% (95% CI 12-46%) with eight PRs; the median durations of response were 2.8 months and 2.5 months respectively. Sites of response were similar in both groups. There was no difference between the two groups in progression-free survival or overall survival (median survival 5 months for BCDT with IL-2/IFNalpha and 5.5 months for BCDT alone). Although 3 days of subcutaneous IL-2 resulted in significant lymphopenia, evidence of immune activation was indicated by a significant rise in the percentage of CD56- (NK cells) and CD3/HLA-DR-positive (activated T cells) subsets, without any change in the percentage of CD4 or CD4 T-cell subsets. Toxicity assessment revealed a significantly higher incidence of severe thrombocytopenia in patients treated with combination chemotherapy than with chemotherapy alone (37% vs 13%, P = 0.03) and a higher incidence of grade 3/4 flu-like symptoms (20% vs 10%) and fatigue (26% vs 13%). The addition of subcutaneous IL-2 and IFNalpha to BCDT chemotherapy in a randomized phase II trial resulted in immune activation but did not improve response rates in patients with metastatic melanoma, and indeed may increase some treatment-related toxicity.