Differential effect of nitric oxide synthase inhibition on sigmoid colon longitudinal and circular muscle responses to nicotine and nerve stimulation in vitro

BACKGROUND

Nicotine has been shown to release nitric oxide from nerves in human sigmoid colon. This effect has been used to investigate the innervation and functional relationship of the longitudinal and circular muscle layers.

METHODS

Strips of longitudinal and circular muscle were obtained from 19 patients with colorectal cancer. The strips from ten patients were subjected to electrical field stimulation (EFS) in vitro using stimulus parameters for selective stimulation of nerves. The effect of nicotine 1-10 micromol/l on EFS responses was then measured in the presence and absence of a nitric oxide synthase inhibitor, nitro-L-arginine methyl ester (L-NAME) 200 micromol/l. The effect of nicotine on spontaneous activity was investigated in the muscle strips from the other nine patients.

RESULTS

Both longitudinal and circular strips responded to EFS with contraction. The time to achieve a peak contractile response (time to peak; TTP) was significantly longer (P<0.001) in circular strips. L-NAME reduced the mean(s.e.m.) TTP in circular muscle from 23.3(2.0) to 17.2(1.5) s (P=0.007) and altered its pattern of response to resemble that of longitudinal muscle. Nicotine 10 micromol/l reduced the contraction to EFS in circular (P<0.001) but not in longitudinal (P=0.347) muscle. The nicotine-induced reduction in circular muscle contraction was blocked by L-NAME 200 micromol/l (P=0.005).

CONCLUSION

These findings suggest that nitric oxide release on neural stimulation is greater in circular than in longitudinal muscle.

Effect of smoking and transdermal nicotine on colonic nicotinic acetylcholine receptors in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a disease largely of non-smokers, in which nicotine is of therapeutic value. The mode of action is unknown, but may involve nicotinic acetylcholine receptors (nAChRs) in the bowel wall.

AIM

To investigate the presence of nAChRs in rectal mucosa, and the effect of smoking and nicotine on their expression.

DESIGN

Prospective case-control study.

METHODS

In situ hybridization (ISH) and immunocytochemistry (ICC) were used to show alpha3 nAChRs in colonic mucosa. Rectal mucosa was examined from controls (n=55) and patients with inactive UC (n=62), both smokers and non-smokers, by ICC, using two antibodies to show the density and distribution of receptors in the mucosa. Non-smokers with UC (n=43) were given transdermal nicotine or placebo patches for 6 months, and rectal biopsies, taken before and after treatment, were examined by ICC to show nAChRs.

RESULTS

In normal colon, ISH and ICC showed alpha3 subunit in a wide variety of cells, including mucosal epithelium. In rectal biopsies, neither smoking nor nicotine influenced the expression of alpha3 immunoreactivity in epithelium, either in controls or UC. However, controls had a significantly greater density of immunodetectable mucosal epithelium alpha3 subunit, compared with UC patients.

DISCUSSION

The presence of nAChRs in colonic epithelium may be pertinent to the beneficial effect of nicotine in UC, but since neither smoking nor nicotine treatment is associated with any change in the expression of epithelial alpha3 nAChRs, the effect may be due to functional changes in the receptor. The decreased number of alpha3 nAChRs in UC compared with controls may be related to an increased cell turnover in UC.

Megacystis-microcolon-intestinal hypoperistalsis syndrome and the absence of the alpha3 nicotinic acetylcholine receptor subunit

BACKGROUND & AIMS

The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disease of childhood that presents early with intestinal hypoperistalsis, hydronephrosis, and hydroureters. Transgenic mice that lack the alpha3 subunit containing nicotinic acetylcholine (nAChR) have a phenotype similar to that of MMIHS.

METHODS

We examined the expression of this subunit in control and MMIHS tissue derived from patients using in situ hybridization (ISH) and immunocytochemistry (ICC).

RESULTS

In controls, both techniques showed a wide distribution of alpha3 nAChRs present in ganglion cells, muscle, and epithelium. By contrast, most MMIHS tissue gave negative staining with ISH and variable results with ICC.

CONCLUSIONS

These observations are consistent with a lack of alpha3 nAChRs contributing to the pathogenesis of MMIHS.

Innovative treatment approaches for rheumatoid arthritis. New cyclo-oxygenase and cytokine inhibitors

A need remains for the development of more effective therapies for the treatment of rheumatoid arthritis (both NSAIDs and DMARDs). The NSAIDs remain the cornerstone of symptomatic therapy, but concern remains about their safety, potential for the delay in commencing definitive therapy and theoretical pro-inflammatory effects. Each of the NSAIDs reviewed here do provide an advantage over therapies previously available and should prove to be useful additions to the rheumatologists' therapeutic armament.

University-state hospital collaboration in an inpatient psychiatric rehabilitation program

From 1981 until present the Department of Psychology of the University of Nebraska-Lincoln has collaborated with the Lincoln Regional Center, a state hospital, on an inpatient psychiatric rehabilitation project. The University provides clinical psychology services under contract, including direct clinical services and consultation on program development. The project includes a 40-bed inpatient treatment unit, which represents a clinical training and research site for University faculty and graduate students. Program evaluation data indicate the collaboration has produced a cost-effective state-of-the-art treatment program, now considered a model for psychiatric rehabilitation services across the state. The collaboration played a key role in securing two major grants, one for specialty training for clinical psychologists in schizophrenia and psychiatric rehabilitation, one for a treatment outcome study. Facilitating factors in the project include convergence of the collaborators' professional and research interests with national and state mental health policy. Obstacles include hospital administrative policies which fail to recognize or appreciate requirements for program management and accountability, and unwillingness to recognize program leadership from nonmedical professionals.

Clinical cheating and moral development

Clinical cheating is one of the most devastating ways students can breach moral principles, and its prevention should be a priority for nurse educators. Educators can promote the professional integrity of students by integrating moral development into all curricular efforts.

Nurses' knowledge, attitudes, and beliefs regarding organ and tissue donation and transplantation

The acute shortage of human organs and tissues for transplantation has been attributed in part to health professionals, including nurses, for their reluctance to recognize and refer suitable candidates for donation. In 1988, nurses' knowledge, attitudes, and beliefs regarding organ and tissue donation and transplantation were assessed using a 70-item questionnaire. Respondents included 1,683 nurses employed in 62 rural and urban hospitals in the Midwest. Only 365 respondents (21.7 percent) reported having requested tissue donations and 243 (14.4 percent) reported having requested organ donations. However, of those who requested tissue or organ donations, 270 (74 percent) obtained consents for tissues and 150 (61.7 percent) obtained consent for organ donations. Respondents were knowledgeable about organ and tissue donation (mean score of 7.5 on a 0 to 10 knowledge scale with 10 as highest) and reported attitudes and beliefs were moderately positive. Factors that were significantly correlated with the number of requests made for organs and tissues and the number of consents obtained included nurses' knowledge, attitudes, and beliefs about donation; nurses' perception of their own confidence in their ability to request tissues and organs; being a supervisor; and working in an emergency department.

The investigation of osteoradionecrosis of the mandible by near infrared spectroscopy

The results of near infrared spectroscopy in eight patients with osteoradionecrosis of the mandible are presented. These suggest that sites of osteoradionecrosis may be marked by decreased amounts of deoxygenated haemoglobin. The advantages and potential of near infrared spectroscopy are discussed but the technique requires further refinement.

Quantitation of cerebral blood volume in human infants by near-infrared spectroscopy

Current methods for measuring cerebral blood volume (CBV) in newborn infants are unsatisfactory. A new method is described in which the effect of a small change (5-10%) in arterial oxygen saturation (SaO2) on cerebral oxyhemoglobin [HbO2] and deoxyhemoglobin [Hb] concentration is observed by near-infrared (NIR) spectroscopy. Previous experiments in which the NIR absorption characteristics of HbO2 and Hb and the pathlength of NIR light through the brain were defined allowed changes in [HbO2] and [Hb] to be quantified from the Beer-Lambert law. It is shown here that CBV can then be derived from the expression CBV = (delta[HbO2] - delta[Hb])/(2. delta SaO2.H.R.), where H is the large vessel total hemoglobin concentration and R to the cerebral-to-large vessel hematocrit ratio. Observations on 12 newborn infants with normal brains, born at 25-40 wk of gestation and aged 10-240 h, gave a mean value for CBV of 2.22 +/- 0.40 (SD) ml/100 g, whereas mean CBV was significantly higher 3.00 +/- 1.04 ml/100 g in 10 infants with brain injury born at 24 to 42 wk of gestation and aged 4-168 h (P less than 0.05).

Relationship between the P300 auditory event-related potential and automated psychometric tests

Event-related potentials particularly the P3 component have been noted to be abnormal in illnesses affecting cognitive processes, such as dementia. The relationship between the P3 latency and objective tests of mental function in patients with Alzheimer's disease and vascular dementia has been studied. A significant correlation was demonstrated between P3 latency and automated psychometric tests in patients with Alzheimer's disease.

Evaluation of lead, zinc, and copper excretion in chronic moonshine drinkers

To assess the usefulness of various routine and inexpensive tests widely used in the detection of an increased body lead load, the whole blood lead value, the 24-hour urinary excretion of lead, delta-aminolevulinic acid (DALA) and coproporphyrin, the presence of basophilic stippling and the whole blood osmotic fragility test were compared to a 24-hour urinary lead excretion after a calcium disodium edetate (EDTA) mobilization test in 20 chronic moonshine drinkers. Of these tests, only urinary lead excretion after EDTA mobilization was a sensitive indicator of excessive body burden, though a reference value of 650 micrograms urine lead excretion per 24 hours may have excluded some patients with increased lead loads. The reason for increased zinc and copper excretion before and after EDTA mobilization is not known but raises the possibility of their concomitant contamination of moonshine whiskey.

Physical studies of lanthanide binding to concanavalin A

The binding of lanthanide ions to concanavalin A has been studied using circular dichroic, magnetic circular dichroic and fluorescence spectroscopies. A Scatchard analysis of the fluorescence enhancement of Tb3+ binding reveal the presence of two classes of sites. One strong binding site (S3) is present per protomer which is not affected by addition of transition metals or calcium. There are at least three additional weak binding sites per protomer, one of which may be S1. There is virtually no energy transfer from Tb3+ to Co2+ in cobalt-substituted concanavalin A. The S3 site, therefore, must be at least 39 A distant from S1. The circular dichroic spectrum of Co2+ concanavalin A is altered by addition of Gd3+ in a manner consistent with competition for S1. The magnetic circular dichroic spectrum of Pr3+ bound to concanavalin A is not affected by excess Ca2+ or the addition of specific carbohydrate effectors. There is no evidence for lanthanide ion binding to S2.

Height and personality characteristics of 47, XYY males in a sample of tall non-institutionalized males

A sample of 471 enlisted men 183 cm or taller serving in the US Navy, Coast Guard, and Marine Corps was screened for Y-chromosome aneuploidy by use of quinacrine fluorescence of peripheral blood smears. Two 47,XYY males were detected, resulting in a prevalence of 00425 or approximately 1 in 236. The prevalence of 47,XYY males (00331) in a number of samples of tall, non-institutionalized males is significantly higher than the incidence in newborn males (00061), indicating that 47,XYY males are disproportionately represented in tall male populations. The 47,XYY males had significantly higher scores than 46,XY males on the Schizophrenia, Schizophrenia+1K, and Prejudice scales of the Minnesota Multiphasic Personality Inventory and significantly lower scores on the Dominance scale. Since the probability that a randomly selected pair of subjects in the sample had four or more scale scores significantly different from the remainder of the group was greater than 05, it is possible that the differences between the 47,XYY and 46,XY males occurred by chance. On the other hand, one or more of these scales may measure personality dimensions on which non-institutionalized 47,XYY males may, in fact, differ from 46,XY males.

Divergent phenotypes among 48,XXXX and 47,XXX females

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Incidence of gross chromosomal errors among tall criminal American males

Chromosome studies on 129 tall men surveyed in four different institutions for the care of criminal males in Pennsylvaniia showed that 1 in 11 subjects displayed aneuploidy of the sex chromosomes; specifically, five cases of 47,XYY and seven cases of Klinefelter syndrome were identified. All the aneuploid subjects were mentally ill; none had been cytogenetically diagnosed.