Role of nitric oxide in relaxation of the longitudinal layer of rectal smooth muscle

PURPOSE: This study was designed to investigate the role of nitric oxide in neurogenic relaxation of the longitudinal layer of human rectal smooth muscle. METHODS: Tissue was obtained from the mid rectum of patients undergoing anterior resection for carcinoma. Adjacent strips of longitudinal muscle were dissected and mounted in organ baths for isometric tension recording. In preliminary experiments to determine the response of strips to cholinergic, adrenergic, and potential excitatory agonists, strips were superfused with standard Krebs solution (37±0.5°C; pH, 7.4±0.05). Investigation of inhibitory, nonadrenergic noncholinergic responses required the addition of 3×10⁻⁶ M histamine to induce reproducible and stable tension for five-minute “test” periods, during which electrical field stimulation (EFS) and additional drugs were applied. In these experiments, strips were superfused with Krebs solution that contained atropine sulfate (3×10⁻⁶ M) and guanethidine (3×10⁻⁶ M). RESULTS: The response to cholinergic and adrenergic agonists was typical of nonsphincter specialized gastrointestinal smooth muscle. EFS elicited frequency-dependent, neurogenic (tetrodotoxin-sensitive) relaxations of precontracted strips, which were reduced in dose-dependent fashion by addition ofNω-nitro-l-arginine and restored by addition of 3×10 ⁻⁴ M l-arginine but not by d-arginine. Addition of exogenous nitric oxide (sodium nitroprusside) mimicked the relaxant response induced by EFS. CONCLUSION: Smooth muscle from the longitudinal layer of human rectum receives an intrinsic inhibitory innervation mediated by nitric oxide. Supported and financed by the Medical Research Council, United Kingdom. John Stebbing is in receipt of a Medical Research Council Clinical Training Fellowship. Read at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996.     

Transvaginal endosonography: a new method to study the anatomy of the lower urinary tract in urinary stress incontinence

A new method to investigate the anatomy of the lower urinary tract in women is described. Direct ultrasound images of the bladder neck and proximal urethra were obtained using a vaginal endoprobe; the series comprised 100 women with a range of urinary symptoms. The technique was well tolerated by patients and there was no morbidity. Transvaginal endosonography is suitable for the assessment of many aspects of urinary incontinence.     

Internal vascularity of the scaphoid in cadavers after insertion of the Herbert screw

This article describes the effects of various operative exposures for insertion of the Herbert screw on the internal vascularity of the scaphoid. Vessels supplying the proximal 70% to 80% of the scaphoid were intact in all specimens except one, which had a combined palmar and dorsal. approach. Vessels supplying the tubercle and the distal 20%-30% were disrupted in five of 18 specimens undergoing the palmar approach. The palmar approach did not disrupt the significant dorsal blood supply, and the dorsal approach was safe provided care was taken to preserve the visible dorsal vascular leash.     

Serum levels of short-chain fatty acids in cirrhosis and hepatic coma

Short-chain fatty acids cause reversible coma in animals and may contribute to the pathogenesis of the hepatic coma in humans. The concentrations of short-chain fatty acids in peripheral venous blood were significantly elevated in 15 patients with hepatic encephalopathy caused by cirrhosis (362 +/- 83 mumol/L; mean +/- S.E.M.) compared with 17 cirrhotic patients without encephalopathy (178 +/- 57 mumol/L) and 11 normal individuals (60 +/- 8 mumol/L). However, no correlation between the depth of coma and the level of short-chain fatty acids was found after repetitive measurements in the coma group. Compared with normal individuals, all short-chain fatty acids, except valerate, were elevated in patients with hepatic encephalopathy, whereas only the concentrations of isobutyrate and isovalerate were significantly elevated in cirrhotic patients without encephalopathy. The concentrations of short-chain fatty acids in 21 nonencephalopathic cirrhotic patients who underwent catheterization were equally distributed in the aorta (187 +/- 56 mumol/L), the hepatic vein (212 +/- 75 mumol/L), the azygos vein (140 +/- 37 mumol/L) and the renal vein (135 +/- 43 mumol/L) compared with peripheral venous blood (178 +/- 57 mumol/L). This study does not support the idea that short-chain fatty acids are of major importance in the pathogenesis of hepatic coma in patients with cirrhosis.     

Diploma-prepared nurses' use of technological equipment in clinical practice

Increasingly, nurses throughout the western world are receiving their educational preparation for initial registration in a tertiary environment at either the diploma or bachelor degree level The length of time spent in the clinical setting has been reduced considerably, with the elimination of the apprenticeship system and the role of the student nurse as paid staff member Concurrently, the amount of technological equipment used in the health care sector is both increasing rapidly and now found in general wards, not just the traditional 'high tech' environments It is important to evaluate how well the tertiary experience prepares students in terms of their ability to handle common technological equipment such as infusion control devices or suction pumps In the study reported here 245 diploma-prepared registered nurses completed a questionnaire designed to assess how nurses from tertiary institutions perceived their ability to handle technical equipment in the workplace The majority of the respondents had been working for 7 to 12 months No significant relationship was found between the frequency of use of specific items of clinical equipment and whether that item caused the nurse concern in practice There was also no significant relationship between the frequency of use of an item and whether participants believed that competence should be acquired in relation to that item prior to tertiary graduation Although moderate levels of comfort in the use of technical equipment were reported upon entry to the workplace, subjects rapidly acquired high levels of comfort in relation to equipment handling The implications for hospital administrators and tertiary teaching programmes are discussed     

"Chronic painter''s syndrome". A reanalysis of psychological test data in a group of diagnosed cases, based on comparisons with matched controls

Twenty solvent-exposed workers, most of them painters, had been diagnosed as cases of toxic encephalopathy in 1978/79. Two years later they were re-examined with an extensive battery of neuropsychological tests. Their performance was unchanged on retesting. We have now compared their test results with those of non-exposed control subjects. Previous impressions of significant intellectual impairment in the solvent-exposed patients could not be confirmed when the influence of age, education, and intelligence was taken into consideration. The present group with presumed toxic encephalopathy is assumed to be representative of other patients who were similarly diagnosed in our department. The presently reanalyzed cases had been diagnosed as brain damaged and reported as such in the literature. Thus, they may have contributed to the formation of the concept of the "chronic painters' syndrome" with dementia.     

Use of end-tidalPco 2 and transcutaneousPco 2 as noninvasive measurement of arterialPco 2 in extubated patients recovering from general anesthesia

This study was designed to assess the accuracy of end-tidalPco ₂ and transcutaneousPco ₂ as measurements of arterialPco ₂ in extubated, spontaneously breathing patients recovering from general anesthesia. In 30 patients, measurement of arterial transcutaneous, and end-tidalPco ₂ were taken simultaneously with body temperature approximately every 15 minutes over a 2-hour period. ArterialPco ₂ values were corrected for body temperature. Values for Paco ₂ were compared with those forPetCO₂ and Psco ₂ by linear regression analysis and by calculation of bias ± precision. Thirty-six percent of the capnogram tracings obtained did not develop a plateau phase. We found poor correlation between end-tidal and arterialPco ₂ regardless of the shape of the capnogram tracing, as well as poor correlation between transcutaneous and arterialPco ₂. Although the measurements of bias and precision of noninvasivePco ₂ monitors in this population are comparable to studies in other populations, we advise caution in relying on the routine use ofPetCO₂ or Psco ₂ for the noninvasive assessment of respiratory depression in extubated, spontaneously breathing patients recovering from general anesthesia.     

Increased NADPH-diaphorase activity in canine myxomatous mitral valve leaflets

Comparable pathological changes in the mitral valve have been described in dogs, pigs and human patients with myxomatous mitral valve disease (MMVD), i.e., primary mitral valve prolapse. The progressive myxomatous changes are probably a response to repeated impact on the leaflets, and endothelial stress or damage probably plays a central role in the pathogenesis. Little, however, is known about the vasoactive substances that mediate the subendothelial changes. The aim of this study was to investigate the expression of nitric oxide synthase (NOS) in canine mitral valve leaflets and to relate the findings to MMVD changes. The mitral valve was taken post mortem from 12 dogs (six males and six females) and a whole valve NADPH (the reduced form of nicotinamide-adenine dinucleotide phosphate) diaphorase (NADPH-d) reaction was performed. Macroscopical (semiquantitative) and microscopical (computer image analysis) evaluations of the staining due to NADPH-d activity were performed at four specific areas of the valve and related to microscopical signs of MMVD and gross signs of thickening or prolapse, or both. Macroscopically, the NADPH-d colour grade was correlated with the degree of MMVD (P=0.01). In addition, endothelial NADPH-d staining intensity was correlated with macroscopical signs of disease (P=0.004) as well as with collagen degeneration (P=0.008) and deposition of mucopolysaccharides (P=0.02). Age, gender and specific area of the valve did not seem to influence the NADPH-d activity. In conclusion, increased NADPH-d activity, suggesting increased NOS expression, was found in areas of the mitral valve with myxomatous changes. This indicates that nitric oxide (NO) may play a role in the pathogenesis of MMVD in dogs.