L. Illenyi

The NANC relaxation of the human ileal longitudinal and circular muscles is inhibited by MRS 2179, a P2 purinoceptor antagonist

AIMS Functional innervation of the human small intestine may be different from that of experimental animals. These experiments set out to assess the mediating roles of P(2) purinoceptors in the non-adrenergic, non-cholinergic (NANC) relaxation of the human ileum longitudinal and circular muscles. MAIN METHODS In organ bath experiments NANC relaxations were evoked by electrical field stimulation (EFS). The relaxant effects of ATP and sodium nitroprusside were also examined. KEY FINDINGS In the longitudinal muscle, relaxation in response to EFS (2 or 10 Hz for 30 s) or the relaxant effect of exogenous ATP were strongly inhibited or abolished, respectively, by the P(2) purinoceptor antagonist MRS 2179 (10 microM). MRS 2179 had a smaller effect at 3 microM. The NANC relaxation was also inhibited by apamin (3 microM), but not by N(G)-nitro-L-arginine (100 microM), an inhibitor of nitric oxide synthesis. Both apamin (3 microM) and MRS 2179 (3 microM, a concentration below the effective range if administered alone) strongly inhibited the NANC response in preparations pretreated with the nitric oxide synthase inhibitor. NANC relaxations of the circular muscle were also inhibited by MRS 2179 (3-10 microM). SIGNIFICANCE MRS 2179-sensitive P(2) purinoceptors play a mediating role the NANC relaxation in the ileal longitudinal and circular muscle. There seems to be a supra-additive relationship between the purinergic and nitrergic mechanisms in the longitudinal muscle.

Oncogene and tumor suppressor gene expression changes in the peripheral blood leukocytes of patients with colorectal cancer

Aims and background The mortality of colorectal cancer continues to stagnate despite the development of new therapeutic approaches. Therefore, identifying high-risk population groups could contribute to the prevention of a considerable part of deaths caused by colorectal tumors. Methods Fifty patients with colon cancer and 50 patients with other, nonmalignant diseases were selected for the study. Expression of the c-myc, Ha-ras and p53 genes was determined in the peripheral leukocytes of the participants. Results Marked elevations of the expression of all three investigated genes were seen in the colon cancer patients when compared to the controls. Conclusions Our investigations showed that increases in the expression of c-myc, Ha-ras and p53 genes can be demonstrated in the peripheral leukocytes of colon cancer patients. By applying our method to clinical investigations, individuals with a high risk of having developed colon cancer may be identified and early diagnosis may be established.

Unexpected Insensitivity of the Cholinergic Motor Responses to Morphine in the Human Small Intestine

Background/Aims: Morphine is known to inhibit cholinergic contractions of the guinea pig small intestine. This has been compared to the human small intestinal innervated longitudinal muscle in the current study. Methods: Cholinergic primary contractions of human small intestinal longitudinal strips were evoked by electrical field stimulation (EFS; 0.5– 5 Hz in the presence of purinergic and nitrergic blockers or 5 Hz without pretreatment) and recorded isotonically in organ bath experiments. Guinea pig small intestinal segments were also studied. Results and Conclusion: Neurogenic cholinergic contractions of human preparations were unaffected by morphine (1, 2 or 10 µmol/l). Longitudinal contractions of the guinea pig ileum were concentration-dependently suppressed by morphine (0.1–10 µmol/l). It is concluded that myenteric neurons supplying the longitudinal muscle of the human small intestine are much less sensitive to morphine than those of the guinea pig.

The hourglass appearance of the neurofibroma on rectal ultrasound

Colorectal manifestation of von Recklinghausen’s disease is a rare entity. The typical dumbbell shape of the lesion has been described previously, but only from a resected cecal specimen. The authors present the endosonographic appearance of a rectal neurofibroma, which shows a similar hourglass shape, thus facilitating the diagnosis.