Muscarinic modulation of endogenous noradrenaline release from adrenergic terminals in the guinea-pig colon

1 The present study examined the role of muscarinic receptors in the modulation of noradrenaline (NA) release in the guinea-pig isolated distal colon. The spontaneous endogenous NA overflow assayed by HPLC-ED was taken as an index of NA release from enteric noradrenergic nerve terminals. 2 Physostigmine (10 μm ) significantly enhanced spontaneous endogenous NA overflow. Hyoscine (muscarinic antagonist), (R)-(-)-trihexyphenidyl and telenzepine (M₁-selective antagonists), and 11[[2-[(diethylamino)methyl]-1-piperydil]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX 116, M₂-selective antagonist) inhibited NA overflow in a concentration dependent manner, with the following EC₅₀ values: 131.74 (18.19–953.96), 101.62 (58.83–175.60), 150 (60–330), 30 (5–170) nm , respectively. 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, M₁- and M₃- selective antagonist) had no significant effect up to 100 μm . 3 The muscarinic agonist oxotremorine inhibited NA overflow in a concentration dependent manner, with an EC₅₀ value of 0.67 (0.30–1.51) μm . The response to oxotremorine was inhibited by muscarinic antagonists with the following order of potency: hyoscine = (R)-(-)-trihexyphenidyl = telenzepine > 4-DAMP >> AF-DX 116. 4 In the presence of 3 μm tetrodotoxin (TTX), the effect of oxotremorine and 4-DAMP was unchanged, while hyoscine, (R)-(-)-trihexyphenidyl, telenzepine and AF-DX 116, instead of inhibiting, significantly enhanced NA overflow. 5 The present results indicate that, in the guinea-pig colon, endogenous acetylcholine sustains spontaneous NA release by activating muscarinic receptors possibly located on interneurones. In addition, inhibitory muscarinic receptors may exist on adrenergic terminals.     

Double-stranded-RNA-dependent protein kinase and TAR RNA-binding protein form homo- and heterodimers in vivo.

The yeast two-hybrid system and far-Western protein blot analysis were used to demonstrate dimerization of human double-stranded RNA (dsRNA)-dependent protein kinase (PKR) in vivo and in vitro. A catalytically inactive mutant of PKR with a single amino acid substitution (K296R) was found to dimerize in vivo, and a mutant with a deletion of the catalytic domain of PKR retained the ability to dimerize. In contrast, deletion of the two dsRNA-binding motifs in the N-terminal regulatory domain of PKR abolished dimerization. In vitro dimerization of the dsRNA-binding domain required the presence of dsRNA. These results suggest that the binding of dsRNA by PKR is necessary for dimerization. The mammalian dsRNA-binding protein TRBP, originally identified on the basis of its ability to bind the transactivation region (TAR) of human immunodeficiency virus RNA, also dimerized with itself and with PKR in the yeast assay. Taken together, these results suggest that complexes consisting of different combinations of dsRNA-binding proteins may exist in vivo. Such complexes could mediate differential effects on gene expression and control of cell growth.     

Choledochal duct cyst: resection with physiologic reconstruction.

BACKGROUND. The accepted surgical treatment of choledochal duct cyst is complete excision and enteric drainage through an intestinal conduit. Peptic ulceration and fat malabsorption have been reported after Roux-en-Y reconstruction. Such long-term complications may be avoided by a technique that simulates normal physiology. METHODS. Twenty-one patients have undergone resection of a choledochal duct cyst in the past 12 1/2 years. The pathologic duct is resected to the level of normal mucosa. A short segment of jejunum with a intussusception valve (1.5 to 2 cm) is interposed between the common hepatic duct and the duodenum. The medical records and all radiographs of each patient were reviewed. Eighteen children were reexamined or the parents were contacted by phone. RESULTS. Twenty of 21 patients recovered without major perioperative complications. Twelve of them are well and have no symptoms at 3 to 12+ years (mean, 6 years) after operation. Four children are currently well 6 to 19 months after operation. Three children were well when lost to follow-up. Two patients have radiographic evidence of incompetence of the interposition valve. One of these, who initially underwent operation at 9 months of age, was reexplored at 10 months and at 10 years for a stricture at the hepaticojejunal anastomosis. The other, a 7-year-old girl who was admitted with jaundice and pancreatitis, has had episodic abdominal pain for 7 years after operation but is well. CONCLUSIONS. The valved jejunal interposition hepaticoduodenostomy offers superior biliary reconstruction after excision of a choledochal duct cyst. Normal physiology is simulated, with bile draining directly into the duodenum. A short conduit prevents stasis, and biliary reflux is minimized with the addition of an intussusception valve.     

Efficacy of diltiazem in variant angina. Results of a double-blind crossover study in CCU by Holter monitoring. The possible occurrence of a withdrawal syndrome

The short and long term efficacy of diltiazem, a calcium-entry blocker, has been evaluated in a group of ten patients with Prinzmetal's variant angina admitted to a CCU. In the short term part of the study, after a run-in period, diltiazem 60 mg tid and placebo were administered alternatively during 4 randomized 72 hour periods. Response was assessed using continuous Holter monitoring, measuring the frequency of transient ischemic attacks. During the run-in period the number of episodes/day/patient was 16.1. No episodes of transient ST segment elevation were recorded during both periods of diltiazem treatment in 3 patients and during one of the two periods in 4. For the group as a whole the number of episodes during the first placebo period was not statistically different from that during the run-in period (208 versus 161). No statistically significant difference was also found in 8 patients comparing the number of episodes during the second placebo period and the run-in period (166 versus 101). During each period of diltiazem treatment an highly significant reduction in the number of episodes was observed (43 and 5, p = .006 and p = .02). Two patients did not complete the study protocol. Both patients had a worsening of angina during the first placebo period following diltiazem treatment. One of them developed an acute myocardial infarction. The possible occurrence of a rebound phenomenon after withdrawal of diltiazem seems to be indicated, in 6 patients, by a significant increase in the number of ischemic episodes recorded during the placebo period following active treatment in respect to the number during the first placebo period (159 versus 73, p = .04).(ABSTRACT TRUNCATED AT 250 WORDS)     

Sympathetic overactivity in patients with chronic renal failure.

BACKGROUND: Hypertension is a frequent complication of chronic renal failure, but its causes are not fully understood. There is indirect evidence that increased activity of the sympathetic nervous system might contribute to hypertension in patients with end-stage renal disease, but sympathetic-nerve discharge has not been measured directly in patients or animals with chronic renal failure. METHODS: We recorded the rate of postganglionic sympathetic-nerve discharge to the blood vessels in skeletal muscle by means of microelectrodes inserted into the peroneal nerve in 18 patients with native kidneys who were undergoing long-term treatment with hemodialysis (of whom 14 had hypertension), 5 patients receiving hemodialysis who had undergone bilateral nephrectomy (of whom 1 had hypertension), and 11 normal subjects. RESULTS. The mean (+/- SE) rate of sympathetic-nerve discharge was 2.5 times higher in the patients receiving hemodialysis who had not undergone nephrectomy than in the normal subjects (58 +/- 3 vs. 23 +/- 3 bursts per minute, P < 0.01). In contrast, the rate of sympathetic-nerve discharge was similar in the patients receiving hemodialysis who had undergone bilateral nephrectomy (21 +/- 6 bursts per minute) and the normal subjects. The rate of sympathetic-nerve discharge in the patients receiving hemodialysis who had not undergone nephrectomy was also significantly higher (P < 0.01) than that in the patients with bilateral nephrectomy, and it was accompanied in the former group by higher values for vascular resistance in the calf (45 +/- 4 vs. 22 +/- 4 units, P < 0.05) and mean arterial pressure (106 +/- 4 vs. 76 +/- 14 mm Hg, P < 0.05). The rate of sympathetic-nerve discharge was not correlated with either plasma norepinephrine concentrations or plasma renin activity. CONCLUSIONS: Chronic renal failure may be accompanied by reversible sympathetic activation, which appears to be mediated by an afferent signal arising in the failing kidneys.     

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by strand displacement amplification and relevance of the amplification control for use with vaginal swab specimens

Vaginal swab specimens may be preferable to cervical swab or urine specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae because of the ease of specimen collection and transport. The purpose of this study was to evaluate whether vaginal swab specimens are equivalent to cervical swab specimens for the detection of N. gonorrhoeae and C. trachomatis by the Becton Dickinson strand displacement amplification assay (SDA) with the BDProbeTec ET instrument and then to evaluate the use of the amplification control in a clinical research setting. In the first phase, vaginal and cervical swab specimens were obtained from 455 symptomatic women aged 18 to 40 attending primary health care and sexually transmitted disease clinics. Thirty-nine specimens (8.6%) had true-positive results for N. gonorrhoeae and 37 specimens (8.1%) had true-positive results for C. trachomatis. The sensitivity of SDA was superior to that of culture for the detection of N. gonorrhoeae with vaginal swab specimens and equivalent to that of the Roche PCR for the detection of C. trachomatis with cervical swab specimens. In the second phase of the study, 1,411 consecutively collected vaginal swab specimens were evaluated, with 357 (25.3%) specimens giving indeterminate readings on the basis of the result for the amplification control. The prevalences of sexually transmitted pathogens in vaginal swab specimens with and without use of the amplification control were 6.0 and 5.8%, respectively, for C. trachomatis and 3.1 and 3.0%, respectively, for N. gonorrhoeae. Although, vaginal swab specimens were equivalent to cervical swab specimens for the detection of N. gonorrhoeae and C. trachomatis by SDA with respect to sensitivity, one in four vaginal swab specimens yielded an indeterminate result when the amplification control was used. The amplification control has limited value for use with vaginal swab specimens.     

Cytokine pattern in allergic and non-allergic chronic rhinosinusitis in asthmatic children

BACKGROUND: Rhinosinusitis represents one of the most common chronic diseases. The association of rhinosinusitis with asthma has been frequently reported. Eosinophils and Th2 cells play a pathogenic mechanism in asthma. OBJECTIVE: The aims of the study were to evaluate the cytokine pattern in chronic rhinosinusitis in asthmatic children and to compare the findings in allergic vs. non-allergic asthmatics. METHODS: Thirty-five asthmatic children were evaluated, 19 males and 16 females, with an average age of 8.7 years. All children were asthmatic and suffered from chronic rhinosinusitis. Twenty were allergic and 15 were non-allergic. Ten healthy children were studied as normal controls. Evaluated parameters were the levels of the following cytokines: IL-1beta, IL-4, IL-6, IL-8, IL-12, IFN-gamma and TNF-alpha. Cytokines were recovered from rhinosinusal lavage and measured by immunoassays. Nasal cytology was also performed in all subjects and inflammatory cells were counted by conventional staining. RESULTS: Allergic subjects showed a significant increase of IL-4 (P < 0.01) and TNF-alpha (P < 0.05) and a significant decrease of IL-12 (P < 0.05) and of IFN-gamma (P < 0.0001), whereas IL-1beta, IL-6 and IL-8 were not significantly increased. Non-allergic children showed a significant increase of IL-4 (P < 0.05) and a significant decrease of IFN-gamma (P < 0.0001), IL-12 was not significantly decreased, and IL-1beta, IL-6 and IL-8 were not significantly increased. A significant inflammatory infiltrate was present in all asthmatic children. Significant correlations were demonstrated between IL-4 and IL-12 (P < 0.001), IL-12 and IFN-gamma (P < 0.001), IL-8 and neutrophils (P < 0.01), and TNF-alpha and monocytes/macrophages (P < 0.05), in allergic asthmatics. IL-4 and IL-12 were significantly correlated (P < 0.05) as well as IL-8 and neutrophils (P < 0.01) in non-allergic asthmatics. CONCLUSION: This study shows that allergic asthmatic children with chronic rhinosinusitis have a typical Th2 cytokine pattern, but also non-allergic asthmatic children share a similar pattern. These findings would suggest the existence of a common pathophysiological mechanism shared by upper and lower airways and are consistent with the concept of united airways disease.     

Review article: Structure and function of the epididymis

Summary Testicular spermatozoa are functionally immature in that they cannot fertilize ova. It was first demonstrated by Young [171, 172] that spermatozoa undergo certain changes as they migrate through the epididymis. He proposed that spermatozoa ripen during epididymal transit. It is now known that specific maturational changes occur in spermatozoa during epididymal transit which result in their developing the ability to fertilize ova. Concomitant with this functional maturity are changes in spermatozoal morphology, motility, chemistry, permeability, density and metabolism. It is apparent that in some way not understood these changes are necessary for sperm to achieve the ability to complete the fertilization process. When these mechanisms are understood, we may be able to effectively treat conditions such as necrospermia or abnormally low sperm motility. Furthermore, with the development of the hamster-egg penetration test a new type of male infertility has become evident in recent years; the inability of otherwise normal sperm to penetrate an ovum. It is during epididymal transit that this ability is normally acquired. Thus, any insight into how sperm attain the capacity to penetrate an ovum could lead to an effective treatment of patients whose sperm do not have this ability. In addition, the epididymis holds significant promise as the site of action for a male contraceptive. Thus, it is the purpose of this review to describe the structure and function of the mammalian epididymis with particular emphasis on the factors regulating sperm maturation.