Gastrointestinal hormone receptors on isolated smooth muscle cells from gastric antrum of the rabbit

The regulation by gastrointestinal polypeptide hormones of contraction and relaxation of functionally isolated smooth muscle cells from gastric antrum of the rabbit has been investigated. Gastrin, cholecystokinin (CCK-8) and motilin induced a rapid contraction of isolated cells: significant response occurred within a 5-sec incubation with these peptides and maximal response (40% decrease in cell length) after 30 sec. A higher sensitivity of smooth muscle cells to gastrin and CCK-8 than to motilin stimulations was demonstrated (EC50 = 10 pM for both gastrin and CCK-8 and EC50 = 1 nM for motilin). The minimal gastrin fragment required to get full contraction was the C-terminal pentapeptide amide common to gastrin and CCK. Proglumide inhibited gastrin- or CCK-8- but not motilin-induced contractions with an IC50 of 50 microM. contraction induced by gastrin and motilin required normal levels of extracellular calcium, whereas that due to CCK-8 seemed to be independent of extracellular calcium. Vasoactive intestinal polypeptide (VIP) caused a relaxation of smooth muscle cells maximally contracted by carbachol or CCK-8 or gastrin (EC50 = 2.2 nM) with a parallel increase in intracellular cAMP content.     

Temporomandibular joint arthrography following surgical treatment of internal derangements

Arthrograms of the temporomandibular joint were obtained in 20 symptomatic joints that had previous reconstructive arthroplasty with disk repositioning because of internal derangements. Preoperative arthrograms were available for comparison in 18 joints. Symptoms resulting in a postoperative arthrogram included pain, limited ability to open the mouth, and clicking of the joints. Postoperative arthrographic findings included limited anterior translation of the condyle (90%), irregularity in outline of the intraarticular contrast agent (60%), a conical configuration of the posterior recess (25%), decreased size of the joint (28%), anterior displacement of the meniscus (25%), and perforated meniscus (15%). Many of these findings may have resulted from fibrosis and scarring, which may be a response to intraarticular bleeding. The mechanism by which the fibrosis causes the postsurgical arthrographic features is discussed.     

Induction of sister chromatid exchanges by cypermethrin and carbosulfan in bone marrow cells of mice in vivo

The public health effects of pesticides cannot be denied. However, the undesired effects of chemical pesticides have been recognized as a serious public health concern during the past decades. The present study describes the genotoxic effects of two pesticides, namely cypermethrin and carbosulfan, in a murine test system in vivo. The test parameter used was analysis of sister chromatid exchanges (SCE) in bone marrow cells. Both cypermethrin (5, 10 and 20 mg/kg) and carbosulfan (1.25, 2.5 and 5 mg/kg) induced significant increases in the frequency of SCEs (P < 0.001). However, no significant dose-response correlation could be found for either of the pesticides. Carbosulfan induced a cell cycle delay, as evidenced by an increase in average generation time accompanied by accumulation of cells in the first division cycle, but cypermethrin did not induce any such response. The present study indicates that carbosulfan has a higher potential to cause genetic alterations than cypermethrin in mice and may also pose a mutagenic risk to human beings.     

Dendritic cells generated in the presence of GM-CSF plus IL-15 prime potent CD8+ Tc1 responses in vivo

Dendritic cells (DC) comprise a system of professional antigen-presenting cells, which induce the stimulation of very rare antigen-specific naive T cells. DC progenitors can be stimulated to differentiate into immature DC by various growth factors, including GM-CSF and IL-4. Here we show that IL-15, in combination with GM-CSF, is a growth factor for murine DC. Murine bone marrow cells, depleted of T cells, B cells, I-A+ cells and Gr-1+ granulocytes, and cultured in the presence of GM-CSF plus IL-15 (IL-15 DC), yielded DC expressing high levels of CD11c and MHC class II molecules, as well as CD11b. These cells expressed significant levels of CD40, CD80 and CD86, and could stimulate allogeneic CD4+ T cells efficiently. Interestingly, IL-15 DC were far superior to DC generated with GM-CSF plus IL-4 in stimulating allogeneic CD8+ T cells in vitro. Consistent with this, IL-15 DC induced much more potent antigen-specific CD8+ T cell responses with high levels of Th1 cytokines in vivo, compared to DC generated with GM-CSF plus IL-4, or with GM-CSF plus TGF-beta, or with GM-CSF alone. Together, these data suggest that IL-15 promotes the development of DC, which induce potent Th1 and Tc1 responses in vivo. This suggests potential roles for these IL-15 DC cells in the immunotherapy of tumors and infectious diseases.     

Cimetidine — antacid combination as premedication for elective Caesarean section

The effect of premedication with an oral antacid (magnesium trisilicate), oral cimetidine or a combination of both was studied in 80 patients undergoing elective Caesarean section. Twenty patients served as untreated controls. Seventy per cent of the patients were in the high risk range for acid aspiration Pneumonitis (pH < 2.5 plus gastric coment volume > 25 ml). Antacid therapy was effective in raising pH but the gastric volume remained high in 50 per cent of the patients. Cimetidine was effective in decreasing gastric volume and raising pH but the pH was still <2.5 in two patients. None of the patients given the cimetidine-antacid combination were in the high risk range for acid aspiration Pneumonitis. The combination of an oral dose of Cimetidine 400 mg, three to four hours before the operation followed by 20 ml of magnesium trisilicate one hour preoperatively proved to be the most efficacious regimen for prophylaxsis against Mendelson’s syndrome in elective Caesarean section. Recent reports have suggested that non-particulate antacids (e.g., sodium citrate) may be preferable to particulate antacids such as magnesium trisilicate.     

"Gastrin" and "CCK" receptors on histamine- and somatostatin-containing cells from rabbit fundic mucosa-II. Characterization by means of selective antagonists (L-364,718 and L-365,260).

In the preceding paper, by means of selective agonists to gastrin (HG-17) and cholecystokinin (CCK-39), we evidenced the existence of "gastrin-type" receptors that could regulate histamine release and "CCK-type" receptors that could stimulate somatostatin release in isolated rabbit fundic non-parietal cells (F1 cells). Furthermore, these receptors could induce phosphoinositide breakdown. To confirm the involvement of these receptor types in these biological and biochemical processes, we used selective antagonists, L-364,718 (3-(benzoylamino)-benzodiazepine) specific to "CCK-A-type" receptor and L-365,260 (3-(acylamino)-benzodiazepine) specific to "gastrin/CCK-B-type" receptor. Neither L-364,718 nor L-365,260 alone caused any significant stimulation of [3H]inositol phosphate ([3H]InsP) production and release of histamine or somatostatin-like immunoreactivity (SLI). Each analogue inhibited in a dose-dependent manner [125I]HG-17 or [125I]CCK-39 binding to F1 cells, [3H]InsP accumulation and histamine and SLI release stimulated by HG-17 or CCK-39. L-365,260 appeared to be 30-70 times more potent than L-364,718 in inhibiting [125I]HG-17 binding to F1 cells, as well as HG-17-induced [3H]InsP accumulation and HG-17-or CCK-39-enhanced histamine release (IC50 values: approximately 5-20 nM for L-365,260 and approximately 200-1500 nM for L-364,718). In contrast, L-364,718 was 200 to 400 times more potent than L-365,260 in inhibiting [125I]CCK-39 binding to F1 cells, CCK-39-induced [3H]-InsP accumulation and SLI release stimulated by CCK-39 or HG-17 (IC50 values: approximately 0.3-1 nM for L-364,718 and 100-200 nM for L-365,260). These results led to conclude: (i) the existence of a "gastrin-type" receptor related to histamine release: (ii) the existence of a "CCK-A-type" receptor related to somatostatin release; (iii) the existence of "gastrin type" and "CCK-A-type" receptors linked to the phosphoinositide breakdown pathway.