Capsaicin-induced bladder overactivity and nociceptive behaviour in conscious rats: involvement of spinal nitric oxide

To investigate the role of nitric oxide (NO) in spinal regulation of lower urinary tract function and bladder nociceptive behaviour, cystometry was performed in conscious rats. The effects of intra-arterial and intrathecal administration of the NO synthase (NOS)-inhibitor, L-NG-nitroarginine methyl ester (L-NAME), were studied on volume- and capsaicin-induced micturitions. The incidence of nociceptive behaviour after intravesical capsaicin was investigated in the absence and presence of L-NAME. Intrathecal L-NAME (0.5 mg) had no effect on the normal, volume-induced micturition. Intravesical capsaicin (30 microM) increased the micturition pressure (p < 0.01), the basal pressure (p < 0.01) and decreased the bladder capacity (p < 0.01) and the micturition volume (p < 0.01). Administration of L-NAME intrathecally (0.5 mg) or intra-arterially (25 mg/kg) had no effects on the capsaicin-induced bladder activity. During capsaicin-infusion, the rats showed signs of distress such as licking and head-turning directed toward the abdomen. This nociceptive behaviour was shown during 31 +/- 3% (n = 6) of the observation period. The capsaicin-induced nociceptive behaviour was markedly reduced by intrathecal and to a less extent by intra-arterial, administration of L-NAME. The percentage time spent licking and head-turning was reduced to 11 +/- 2%, n = 6 (p < 0.001) and 18 +/- 3%, n = 6 (p < 0.05) in rats treated with intrathecal and intra-arterial L-NAME, respectively. The results suggest that NO is not involved in the spinal regulation of the volume- or capsaicin-induced micturition. In contrast, the nociceptive behaviour evoked by intravesical capsaicin seems to involve spinal NO.

Polyamines regulate both transcription and translation of the gene encoding ornithine decarboxylase antizyme in mouse

The degradation of ornithine decarboxylase (ODC) is mediated by antizyme, a protein regulated by the end-products of ODC activity, the polyamines. High levels of polyamines induce a +1 ribosomal frameshift in the translation of the rat antizyme message leading to the expression of a full-length protein. We have studied whether the regulation of antizyme expression occurs only at the level of translation or whether polyamine levels also affect the transcription of the antizyme gene. Thus, we have cloned and sequenced the mouse homologues of the rat ODC-antizyme gene and cDNA. Northern blot analysis shows that although high concentrations of polyamines do not affect the steady-state levels of antizyme message in L1210 leukemia cells, polyamine depletion using 2-(difluoromethyl)ornithine [Orn(F2Me)] leads to a marked decrease in mRNA levels. Results of transient transfections of luciferase-reporter-gene constructs driven by antizyme promoter fragments in untreated and Orn(F2Me)-treated Balb/C 3T3 cells indicate that the transcription of the antizyme gene is altered upon polyamine depletion. The amount of antizyme protein on Western blots was also altered by polyamine depletion and addition, and the polysomal distribution of antizyme message suggests a general translational increase of the message when polyamine concentrations are high. These results indicate a role for polyamines in the transcriptional and translational regulation of ornithine decarboxylase antizyme.

Effects of the K+ channel opener, ZD6169, on volume and PGE2-stimulated bladder activity in conscious rats

PURPOSE

To investigate the effects of the new K(ATP) channel opener, ZD6169, shown to have an in vivo selectivity for the bladder, on bladder activity in rats.

MATERIALS AND METHODS

ZD6169 was given intra-arterially (i.a., 0.1 and 1 mg./kg.) or orally (3 mg./kg.) to conscious Sprague-Dawley rats undergoing continuous cystometry. Investigations were also performed before and after stimulation of bladder activity by intravesical prostaglandin (PG) E2.

RESULTS

Intra-arterial ZD6169 increased residual volume, but caused no changes in other cystometric parameters. In rats receiving oral ZD6169, cystometric parameters were compared (every hour up to five hours) to those recorded in rats receiving oral vehicle. No differences were found, except in threshold pressure, which was significantly increased. Intravesical PGE2 20 microM increased micturition and basal pressures, and decreased bladder capacity and micturition volume. ZD6169 1 mg./kg., given i.a., reduced or completely prevented the activity induced by intravesical PGE2. Three hours after orally administered ZD6169 (3 mg./kg.), intravesical PGE2 20 microM had no effect. Three hours after oral administration of vehicle, the effects of PGE2 were attenuated, but still statistically significant.

CONCLUSIONS

ZD6169, given i.a. or orally, increased threshold pressure, but had otherwise little effect on volume-induced micturition. However, the drug markedly reduced or prevented PGE2-induced bladder activity when given i.a.; it was also effective when given orally. If ZD6169 has inhibiting effects on bladder contraction in man without any cardiovascular actions, the drug may represent a novel, promising way of treating bladder overactivity.

Eradication of penicillin-resistant pneumococci in the nasopharynx with antibiotic combinations including rifampicin: experiences from the South Swedish Pneumococcal Intervention Project

39 children with prolonged nasopharyngeal carriage (48-328 days) of intermediately to highly penicillin-resistant pneumococci (PRP) were treated for 7 days with rifampicin in combination with amoxicillin (n = 18) erythromycin (n = 17) or clindamycin (n = 4), according to resistance pattern. In all children, except for 1 carrying a rifampicin-resistant strain, control cultures from the nasopharynx 1-2 weeks after the last antibiotic dosage, yielded no growth of PRP. In 2 brothers, PRP with the same serogroup and resistance pattern were found in nasopharynx 10 weeks after the antibiotic treatment. These preliminary findings indicate that antibiotic regimens including rifampicin are effective in eradicating nasopharyngeal carriage, but reappearance of the same strain may occur after several weeks. Such treatments should be given with caution due to the risk of selecting rifampicin-resistant strains. Further controlled studies are needed to determine the optimal combination of antibiotics and appropriate duration of therapy.

Duration of nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae: experiences from the South Swedish Pneumococcal Intervention Project

As a part of an intervention project, all detected carriers of penicillin-resistant pneumococci (PRP) (MIC, > or = 0.5 mg/L) in Malmöhus County, southern Sweden, were followed by means of weekly nasopharyngeal cultures. The median duration of carriage in 678 individuals was 19 days (range, 3-267 days). The duration of carriage was longest in children < 1 year old (median, 30 days) and shortest in adults > 18 years old (median, 14 days). Index cases, whose cultures were performed during an acute infection, were carriers for a mean of 10 days longer than asymptomatic contact cases (P < .05). The PRP spontaneously disappeared from the nasopharynx within 4 weeks in 68%, within 8 weeks in 87%, and within 12 weeks in 94% of the individuals. Other significant risk factors for prolonged carriage were the occurrence of > 6 episodes of acute otitis media (AOM) or first episode of AOM before the age of 1 year (P < .01), the carriage of PRP by other family members (P < .05), and the obtainment of a first positive culture during the winter months (P < .05).

Fractional factorial design optimization of the separation of pilocarpine and its degradation products by capillary electrophoresis

The separation of pilocarpine and its degradation products by micellar electrokinetic capillary chromatography (MECC) has been optimized by using fractional factorial design of the experiments. Critical parameters were identified in a screening design, and an optimization design was used to optimize the separation. The optimal separation method was based on a borate buffer with sodium dodecyl sulfate (SDS). It is concluded that by using fractional factorial design it is possible to improve the separation of pilocarpine, its trans epimer, isopilocarpine and their hydrolysis products, pilocarpic acid and isopilocarpic acid.

Neurotransmitter release evoked by alpha-latrotoxin in the smooth muscle of the female pig urethra

Neuronal regulation of smooth muscle tone in the female pig urethra has mainly been studied in vitro using electrical field stimulation (EFS) of nerves. Excitatory control is considered to be exerted by released noradrenaline, whereas inhibitory control is non-adrenergic non-cholinergic (NANC), and mediated by nitric oxide (NO), and an as yet unidentified agent. We investigated the functional and morphological effects of alpha-latrotoxin (alphaLTX), a spider neurotoxin believed to cause massive release of vesicle-stored neurotransmitters, on spontaneously developed urethral smooth muscle tone. The effects were compared to those of EFS and high potassium. In the presence of the NO-synthesis inhibitor N(omega)-nitro-L-arginine (L-NOARG: 0.3 mM) both alphaLTX and EFS evoked contractions. After treatment with scopolamine and phentolamine, no contraction was observed, and under these conditions alphaLTX and EFS induced relaxation. At low frequencies (<12 Hz), the EFS-induced relaxations were rapid, whereas at higher frequencies (>12 Hz), they were biphasic, consisting of a rapid first phase followed by a more long-lasting second phase. L-NOARG abolished the relaxations at low frequencies, as well as the first phase of the biphasic relaxation. The second phase was not affected by treatment with L-NOARG, but 0.1 microM omega-conotoxin GVIA, blocker of N-type voltage-operated calcium- channels (VOCCs), markedly reduced or abolished the response. In the presence of L-NOARG or omega-conotoxin GVIA, the alphaLTX-induced relaxation was significantly decreased, and the combination of L-NOARG and omega-conotoxin GVIA further reduced or abolished the relaxation. In preparations-treated with tetrodotoxin or scorpion venom, believed to inactivate nerves by acting on sodium channels, alphaLTX and EFS had no effects. alphaLTX-induced relaxation was not associated with changes in cyclic GMP or cyclic AMP content. High (80 mM) potassium solution induced a triphasic response of the preparation. A transient relaxation was followed by a restoration of tone, and then by a persistent relaxation. The persistent relaxation was slightly reduced by scorpion venom or L-NOARG, but reduced by 50% by a combination of L-NOARG and omega-conotoxin GVIA. Ultrastructural analysis of the urethral circular smooth muscle layer revealed a moderate amount of nerve profiles supplying the smooth muscle. In control preparations, the nerve profiles contained both small synaptic vesicles and large dense core vesicles. alphaLTX caused a major loss of both types of vesicle. The present data suggest that alphaLTX has the ability to release not only adrenergic and cholinergic transmitters, but also NANC mediators of relaxation, including NO, from nerve terminals in the urethra.

Interaction between mothers and infants born at risk during the first six months of corrected age

The effects of preterm birth and the perinatal infant health condition on mother-infant interactions were analysed in 278 mother-infant pairs, divided into four groups according to infants' gestational age at birth: group 1, 23-31 weeks; group 2, 32-36 weeks; group 3, 37-42 weeks; and group 4, a control group of healthy full-term infants. The methodological approach was based on observation of the pairs at 2, 4 and 6 months of infants' corrected age (+/- 1 week) during undressing of the infant and face-to-face interaction. It was found that mother-infant pairs with preterm infants (groups 1 and 2) did not differ in interactional variables from those of the control group. On the other hand, the birth of a full-term infant in need of neonatal intensive care (group 3) affected maternal and infant interactive behaviour. Additionally, infants from group 3 did not show stability in their interactive behaviour between any ages of measurement. This result suggests that interactive behaviour of full-term infants in need of neonatal intensive care are rather unpredictable during their first 6 months of life, which might have contributed to the less optimal interactive pattern observed for their mothers compared with mothers of the control group.

NANC transmitters in the female pig urethra--localization and modulation of release via alpha 2-adrenoceptors and potassium channels

1. To investigate further the release, localization and identity of a non-nitrergic mediator of smooth muscle relaxation in the female pig urethra, we studied the effects of drugs acting at alpha 2-adrenoceptors or K+ channels, the effects of capsaicin and chemical sympathectomy, and the actions of several transmitter candidates. 2. Electrical field stimulation (EFS; frequencies above 12 Hz) of spontaneously contracted smooth muscle strips from the female pig urethra evoked long-lasting, frequency-dependent relaxations in the presence of prazosin, scopolamine, and NG-nitro-L-arginine. Treatment with the selective alpha 2-adrenoceptor agonist UK-14 304 markedly reduced the relaxations evoked by EFS at all frequencies tested (16-30 Hz). The inhibitory effect of UK-14 304 was completely antagonized by the alpha 2-adrenoceptor antagonist rauwolscine. The muscarinic M1 receptor antagonist, pirenzepine, or exogenously administered carbachol, did not have any effects on the electrically evoked relaxations. 3. Inhibition of high conductance Ca2+ activated K+ channels by iberiotoxin or charybdotoxin significantly enhanced the relaxations evoked by EFS at all frequencies. However, inhibition of voltage-sensitive K+ channels with 4-aminopyridine or dendrotoxin-1, treatment with the ATP-sensitive K+ channel blocker, glibenclamide, or treatment with the high and low conductance Ca2+ activated K+ channel blockers, tetraethylammonium chloride and apamin, had no effect on the relaxations evoked by EFS. 4. Electrically evoked relaxations were not affected by adrenergic denervation with 6-hydroxydopamine (6-OHDA) at any frequency. However, treatment with 6-OHDA abolished prazosin-sensitive electrically induced contractions, and a long-lasting relaxation was revealed. Treatment with capsaicin, believed to damage selectively a subpopulation of primary afferent fibres, did not affect basal tone or relaxations evoked by EFS. 5. Exogenously applied vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP)-27, PACAP-38, adenosine, ATP and 5-hydroxy-tryptamine caused relaxations of the urethral preparations, whereas prostaglandin E2 and calcitonin gene-related peptide had no effects. VIP 10-28, alpha, beta-methylene-ATP, reactive blue-2, suramin or indomethacin did not reduce the electrically-evoked relaxations at any frequency. However, the relaxations were slightly reduced by trypsin or alpha-chymotrypsin. 6. The present results suggest that the release of the unknown mediator in the female pig urethra can be modulated via alpha 2-adrenoceptors and high conductance Ca2+ activated K+ channels. Furthermore, the mediator does not appear to be localized to or released from adrenergic or capsaicin-sensitive sensory nerve-endings. The identity of the transmitter remains to be established.

Characterization of angiotensin II formation in human isolated bladder by selective inhibitors of ACE and human chymase: a functional and biochemical study

1. Functional recordings of smooth muscle tension and biochemical experiments on membrane fractions were performed to characterize angiotensin II (AII) formation in human isolated bladder smooth muscle. 2. A novel human chymase inhibitor CH 5450 (Z-Ile-Glu-Pro-Phe-CO2Me) and a recently developed human chymase substrate Pro11-,D-Ala12)-angiotensin I, claimed to be resistant to angiotensin converting enzyme (ACE) and carboxypeptidase, were used. 3. Angiotensin I (AI) (0.3 microM) induced a contractile response amounting to 58 +/- 5% (n=12) of the initial K+ (124 mM)-induced contractions. This response was reduced to 36 +/- 3% (n=8) by the ACE-inhibitor enalaprilat (10 microM), while pretreatment with soybean trypsin inhibitor (STI 200 microg ml(-1)) or CH 5450 (10 microM) had no effect. However, the combination of enalaprilat and STI reduced the AI-induced contractions to 19 +/- 5% (n=6), and the combination of enalaprilat and CH 5450 caused an almost complete inhibition of the AI-induced contractions to 1+/-1% (n=6). 4. The substrate (Pro11-,D-Ala12)-AI (3 microM) produced contractions which amounted to 57 +/- 4% (n=13) of the initial K+ (124 mM) contractions. These contractions were not affected by enalaprilat (10 microM). On the other hand, STI (200 microg ml(-1)) and CH 5450 (10 microM) added separately, depressed the (Pro11-,D-Ala12)-AI-induced contractions to 34 +/- 5% (n=6) and 24 +/- 4% (n=6), respectively. The combination of enalaprilat and STI or enalaprilat and CH 5450 did not produce any further inhibition. 5. Experiments with detrusor membrane fractions incubated with AI (50 microM) were performed. In the presence of enalaprilat (100 microM), carboxypeptidase inhibitor CPI (10 microg ml(-1)) and aprotinin (15 microM), CH 5450 (10 nM-1 microM) caused a concentration-dependent inhibition of AII formation. 6. The results confirm that AII is a potent contractile agent in the human isolated detrusor muscle. They also indicate that the serine protease responsible for AII formation in the human bladder in vitro is human chymase or an enzyme similar to human chymase.

Rapid diagnosis of respiratory Chlamydia pneumoniae infection by nested touchdown polymerase chain reaction compared with culture and antigen detection by EIA

Chlamydia pneumoniae is a common cause of respiratory tract infection and community-acquired pneumonia. During an extensive outbreak of C. pneumoniae in northern Sweden, 319 respiratory samples from 129 persons were collected. Sputum, throat, and nasopharyngeal samples were obtained and analyzed by nested touchdown polymerase chain reaction (PCR), EIA, and culture in Hep-2 and McCoy cells. Serology was performed by complement fixation and microimmunofluorescence tests. By PCR, 30 patients were diagnosed with C. pneumoniae compared with 26 positive by EIA and 23 by culture. The finding of C. pneumoniae in the respiratory samples was accompanied by serology indicating acute infection in 26 (96%) of 27 patients for whom adequate sera were available. Nested PCR was sensitive and reliable for diagnosing acute respiratory C. pneumoniae infection. Sputum samples had the highest diagnostic efficacy, and the nested type of PCR was superior to one-step PCR. EIA and culture were less sensitive than nested PCR.

Regulation of nerve growth factor secretion in smooth muscle cells cultured from rat bladder body, base and urethra

PURPOSE

Interest in the regulation of nerve growth factor (NGF) production in the urinary tract derives from its probable involvement in obstructive, inflammatory and developmental disorders. This study examines receptor-mediated stimuli that alter NGF production in cells of the lower urinary tract.

MATERIALS AND METHODS

Cells were isolated and cultured from the bladder body, base and urethra, confirmed as smooth muscle type by alpha-actin expression, and examined for growth rate and NGF secretion in response to autonomic agonists, cytokines, neuropeptides and growth factors. NGF secreted into the culture medium was quantitated via 2-site enzyme-linked immunoassay. Regional tissue contents of NGF and norepinephrine (NE) were also measured. Only statistically significant differences (Student's t test, p <0.05) are reported.

RESULTS

Cultured urinary tract cells derived from different regions varied in growth rate and NGF secretory activity. Bladder body secreted less NGF than base, and base less than urethra. A similar gradient in growth rate occurred in vitro, with urethral cells most active. However, no regional differences were found in bladder tissue NGF content despite significant variations in NE levels. Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) were among the most potent stimuli to NGF production by cultured cells while cAMP linked receptors and eicosinoids inhibited NGF output.

CONCLUSIONS

A complex system of regionally specific and stimulus-specific control regulates the production of NGF by urinary tract cells. While tissue levels of NGF do not correlate with the density of noradrenergic innervation, bladder innervation is sufficiently dynamic to respond to changes in NGF production and to participate in pathophysiology.

Breast self-examination: an analysis of self-reported practice

The aim of this study was to investigate the relationship between the performance of breast self-examination (BSE) and age, place of residence, ethnic background and religion, as well as whether a group willing to take part in an interview regarding BSE mirrored the whole population. Six hundred and ninety-four (69.4%) women, aged 25-80, responded to the questionnaire. Of these, 69.6% examined their breasts. Whether the subjects lived in urban or rural areas was of no importance for practising BSE, nor was country of birth or number of years in Sweden. A larger proportion of women aged 45-80 practised BSE compared with women aged 25-44 (P < 0.001), the former practising BSE once a month or more. Step-wise logistic regression analysis showed that, for the whole sample as well as for the interview group, age was the only significant predictor of breast self-examination (P < 0.001). There were no significant differences between the whole sample and the interview group. The importance of younger women performing the examination is stressed. Due to nurses being strategically located in a wide range of geographical locations, allowing them to meet women in different settings, they are a good choice for motivating women to practise BSE.

Morphological and functional evidence against a sensory and sympathetic origin of nitric oxide synthase-containing nerves in the rat lower urinary tract

To establish which type of nerves (parasympathetic, sympathetic or sensory) produce nitric oxide in the rat lower urinary tract, chemical denervation of primary afferents and sympathetic nerves was carried out by systemic treatment with capsaicin and 6-hydroxydopamine, respectively, followed by identification of neuronal nitric oxide synthase immunoreactivity. Functional in vitro studies were also performed to examine whether the synthesis and release of nitric oxide was affected following treatment with the respective neurotoxins. Nerve fibres immunoreactive for substance P and calcitonin gene-related peptide were found in control tissue, but could not be detected following capsaicin treatment. In comparison, nitric oxide synthase-immunoreactive fibres appeared to be unaffected by capsaicin treatment. Administration of 6-hydroxydopamine resulted in a complete disappearance of tyrosine hydroxylase-immunoreactive nerves, whereas nitric oxide synthase-containing nerve fibres did not appear to be affected by the treatment. In ultrastructural studies, nitric oxide synthase immunoreactivity, as studied by colloidal gold particles, was found in the axoplasm and not in association with intraneuronal structures or synaptic vesicles. Gold particles representing substance P immunoreactivity were seen as clusters associated with large granular vesicles. In consecutive sections of nerve fibres, substance P and nitric oxide synthase were not found in the same axon profile. In functional studies on urethral tissue, application of capsaicin (1 microM) produced a long-lasting relaxation. The nitric oxide synthase inhibitor NG-nitro-L-arginine (0.1 mM) had no effect on this response. Systemic treatment with capsaicin or 6-hydroxydopamine had no effect on nerve-evoked, nitric oxide-mediated relaxations. The data suggest that nitric oxide synthase-containing nerves in the rat lower urinary tract do not belong to nerve populations sensitive to either the sympathetic neurotoxin, 6-hydroxydopamine, or the sensory neurotoxin, capsaicin.

Carbon monoxide-induced relaxation and distribution of haem oxygenase isoenzymes in the pig urethra and lower oesophagogastric junction

1. The distribution of the carbon monoxide (CO) producing enzymes haem oxygenase (HO)-1 and -2 was studied by immunohistochemistry in the pig's lower urinary tract, including bladder extramural arteries, and the oesophagogastric junction (OGJ). In isolated smooth muscle from the urethra and the OGJ, the mechanisms for CO-induced relaxations were characterized by measurement of cyclic nucleotide levels and by responses to the guanylate cyclase inhibitor methylene blue and some K+ channel inhibitors. 2. HO-2 immunoreactivity was observed in coarse nerve trunks within the smooth muscle of the urethra and OGJ, and in nerve cell bodies of the enteric plexuses of the OGJ. Furthermore, the vascular endothelium of the intramural vessels of the urethra, bladder and OGJ, and the extramural vessels of the bladder, displayed HO-2 immunoreactivity. Two different antisera against HO-1 were used, but only one displayed immunoreactivity in neuronal structures. HO-1 immunoreactivity, as displayed by this antiserum, was seen in nerve cells, coarse nerve trunks and varicose nerve fibres in the smooth muscle of the urethra and OGJ. Some HO-2 and/or HO-1 (as displayed by both HO-1 antisera) immunoreactive cells with a non-neuronal appearance were observed within the smooth muscle of the OGJ, bladder and urethra. 3. In the urethral preparations, exogenously applied CO (72 microM) evoked a relaxation amounting to 76 +/- 6%. The relaxation was associated with an increase in cyclic GMP, but not cyclic AMP, content. CO-evoked relaxations were not significantly reduced by treatment with methylene blue, or by inhibitors of voltage-dependent (4-aminopyridine), high (iberiotoxin, charybdotoxin) and low (apamin) conductance Ca(2+)-activated, and ATP-sensitive (glibenclamide) K+ channels. Bladder strips, and ring preparations from the extramural arteries of the bladder, did not respond to exogenously administered CO (12-72 microM). 4. In the OGJ, exogenously applied CO evoked a relaxation of 86 +/- 6%, which was associated with an increase in cyclic GMP, but not cyclic AMP, content. Treatment with 30 microM methylene blue raised the spontaneously developed muscle tone, and reduced the maximum relaxation evoked by CO to 33 +/- 9%. Addition of 4-aminopyridine, apamin, glibenclamide, iberiotoxin, charybdotoxin or glibenclamide had no effect on the relaxations. 4-aminopyridine (0.1-1 mM), iberiotoxin (0.1 microM) and charybdotoxin (0.1 microM) increased the spontaneously developed tone, and a combination of charybdotoxin and apamin reduced CO-induced (24 microM CO) relaxations. 5. The present findings demonstrate the presence of HO in both neuronal and non-neuronal cells in the pig OGJ and lower urinary tract. CO produces relaxation of the smooth muscle in the OGJ and urethra, associated with a small increase in cyclic GMP concentration in both regions. Relaxations evoked by CO in the urethra do not seem to involve voltage-dependent, low and high conductance, or ATP-dependent K+ channels. However, in the OGJ relaxations evoked by CO can be attenuated by methylene blue and a combination of charybdotoxin and apamin.

Angiotensin II and bladder obstruction in the rat: influence on hypertrophic growth and contractility

The mechanisms and mediators of hypertrophic growth secondary to infravesical urinary outflow obstruction are unknown. The renin-angiotensin system has been implicated in vascular and cardiac hypertrophy, but the involvement of angiotensin II (ANG II) as a trophic factor in the lower urinary tract has not been investigated. In this study, the ANG II subtype AT1 receptor antagonist losartan (DuP 753) was administered perorally (15 mg.kg-1.day-1) for 28 days to rats subjected to partial urethral obstruction or sham surgery. Partial urethral obstruction caused a 3.5-fold increase in bladder weight and a 3-fold increase in bladder protein content compared with sham rats. However, no difference was observed in bladder weight or bladder protein content between losartan-treated rats and rats receiving no drug. Cystometric evaluation of bladder function revealed significant increases in micturition volume, bladder capacity, bladder compliance, and spontaneous contractile activity in rats subjected to partial urethral obstruction compared with sham rats. However, bladder function in rats treated with losartan was not different from bladder function in rats receiving no drug. In vitro studies of isolated bladder tissue showed a weak contractile response to ANG II (1 microM) that amounted to 4.4 +/- 1.0% of the response to K+ (124 mM). The ANG II-induced contraction was abolished by losartan (10 microM) and indomethacin (10 microM). The contractile response to ANG II (1 microM), K+ (124 mM), and transmural nerve stimulation (2 Hz) was reduced in bladder strips from obstructed rats. In conclusion, no evidence was found for involvement of ANG II in development of bladder hypertrophy. The effect of ANG II on bladder smooth muscle tone was minor but was mediated by stimulation of the AT1 subtype receptor.

Distribution and genetic heterogeneity of Puumala virus in Sweden

Small mammals trapped in Sweden were analysed for specific antibody responses against three hantavirus serotypes and for the presence of viral antigen. To determine the genetic identity of viral RNA in lungs of seropositive bank voles (Clethrionomys glareolus), polymerase chain reactions and subsequent partial sequencing of both the M and S segments were employed. The sequences obtained were all identified as Puumala (PUU) virus, with a high degree of heterogeneity between the different geographical localities. Alignment of nucleotide and deduced amino acid sequences, together with phylogenetic analysis, showed that PUU viruses circulating in central Sweden were distinct from those in the northern region. The localization of the two distinct PUU virus genotypes was shown to correlate with the postglacial recolonization of Sweden by bank voles.

Cytokine-induced inflammation in the ovine teat and udder

The inflammatory response, as measured by the accumulation of leukocytes and ovine serum albumin, induced by interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), interleukin-beta (IL-8), and granulocyte-macrophage colony stimulating factor (GM-CSF) was studied in lactating ovine udders, and in test cisterns of dry ewes after surgical closure of the passage between the teat and udder cisterns. In the lactating udders, IL-1 beta and TNF-alpha, but not IL-8 and GM-CSF, induced significant accumulation of cells. In the teat cisterns, all four cytokines IL-1 beta, TNF-alpha, IL-8, and GM-CSF induced significant cell accumulation. IL-1 beta was the most potent cytokine. A slight increase in serum albumin, paralleling the changes in leukocyte numbers, was observed after infusion of IL-1 beta and, to some extent, TNF-alpha. The cell accumulation induced by IL-1 beta or TNF-alpha was dose and time dependent in lactating udders, and time-dependent in teat cisterns. The cell numbers were considerably higher in lactating udders than in teat cisterns after infusion with IL-1 beta. The first influx of cells was observed earlier, and the cell numbers peaked earlier in the teat cisterns than in the lactating udders. IL-8 and GM-CSF induced dose and time dependent cell accumulation in teat cisterns only. The differences between lactating udders and teat cisterns may be attributable to the differences in tissue area involved and the number of receptors available, or to dilution of cytokines in milk, or to presence of inhibitory factors. Differences between cytokines in their inflammatory effects may be explained by their modes of action. IL-1 beta and TNF-alpha have a wide range of cellular functions enabling them to induce a more prominent response than IL-8 and GM-CSF. Furthermore, receptors for IL-1 beta and TNF-alpha are present on a larger number of cell types. Finally, the results indicated that the teat cisterns, being the port of entry for udder infections, as well as the lactating udders are capable of a diversified inflammatory response which is important in the defence against udder infections.

Characterization of nitric oxide synthase activity in sheep urinary tract: functional implications

1. To define further the role of nitric oxide (NO) in urinary tract function, we have measured the presence of nitric oxide synthase (NOS) activity, and its relationship with functional NO-mediated responses to electrical field stimulation (EFS) in the urethra, the detrusor and the ureter from sheep. NOS activity was assayed by the conversion of L-[14C]-arginine to L-[14C]-citrulline. Endogenous production of citrulline was confirmed by thin layer chromatography. 2. NOS enzymatic activity was detected in the cytosolic fraction from tissue homogenates with the following regional distribution (pmol citrulline mg-1 protein min-1): urethra (33 +/- 3.3), detrusor (13.1 +/- 1.1) and ureter (1.5 +/- 0.2). No activity was detected in the particulate fraction of any region. 3. NOS activity was dependent on Ca(2+)-calmodulin and required exogenously added NADPH and tetrahydrobyoptein (BH4) for maximal activity. Exclusion of calmodulin from the incubation mixture did not modify NOS activity, but it was significantly reduced in the presence of the calmodulin antagonist, calmidazolium, suggesting the presence of enough endogenous calmodulin to sustain the observed NOS activity. 4. NOS activity was inhibited to a greater extent by NG-nitro-L-arginine (L-NOARG) and its methyl ester (L-NAME) than by NG-monomethyl-L-arginine (L-NMMA), while 7-nitroindazole (7-NI) was a weak inhibitor and L-cannavine had no effect. 5. Citrulline formation could be inhibited by superoxide dismutase in an oxyhaemoglobin-sensitive manner, suggesting feedback inhibition of NOS by NO. 6. EFS induced prominent NO-mediated relaxations in the urethra while minor or no responses were observed in the detrusor and the ureter, respectively. Urethral relaxations to EFS were inhibited by NOS inhibitors with the rank order of potency: L-NOARG = L-NAME > 7-NI > L-NMMA. 7. In conclusion, we have demonstrated the presence of NO-synthesizing enzymatic activity in the sheep urinary tract which shows similar characteristics to the constitutive NOS isoform found in brain. We suggest that the enzymatic activity measured in the urethral muscle layer may account for the NO-mediated urethral relaxation during micturition whereas regulation of detrusor and ureteral motor function by NOS containing nerves is less likely.

Effect of patient position on the sagittal-plane profile of the thoracolumbar spine

Although the normal sagittal profile of the thoracolumbar spine has been described, this has been obtained primarily by using young individuals standing. We sought to describe the sagittal profile of the thoracolumbar spine in an older population in the supine cross-table lateral position compared with that standing. We enrolled 50 volunteers with no history of back pain or spine deformity and 50 matched subjects with mechanical back pain (LBP) only. Lateral radiographs of the thoracolumbar spine (T10-S1) in both standing and cross-table supine positions were obtained. Lordosis from L1 to S1, kyphosis from T10 to L1, and the changes seen moving from the supine position to standing were calculated. There were few differences comparing the two groups in either the standing or cross-table supine position, or when changing positions. Within each group, however, there were small, but significant, differences in the midlumbar and thoracolumbar spine when comparing supine versus standing. Both asymptomatic individuals and those with a history of LBP demonstrated similar small but statistically significant increases in lumbar lordosis and thoracolumbar kyphosis when standing versus supine. The clinical significance of these findings remains to be determined.

MHC genotype and male ornamentation: genetic evidence for the Hamilton-Zuk model

The major histocompatibility complex (MHC) is an immunologically important cluster of highly variable genes that is known to affect fitness in domesticated mammals and birds. Spur length of male pheasants in southern Sweden correlates with male viability, female mate choice, and offspring survival rate. Here we show by genetic analyses that the MHC genotype is associated with variation in both male spur length and male viability. These are the first data that directly support a 'good genes' hypothesis by Hamilton and Zuk predicting that females discriminate among males on the basis of secondary sexual characters in order to pass on genes for disease resistance that improve fitness in their offspring.