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Biomedical subjects

K Persson

Publications and source records attributed to K Persson.

At least 109 records · Page 6Linked to original sources
PubMed1997

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.

Animals↗
PubMed1997

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.

Adult↗
PubMed1997

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).

Adolescent↗
PubMed1997

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.

Acute Disease↗
PubMed1997

Factors affecting women to practise breast self-examination.

The aim of the study was to identify factors of decisive importance for women's motivation to perform breast self-examination (BSE), which could form the basis of an intervention programme. Interviews were conducted in 1994 with 48 women focusing on four different areas: 1) why the women examined did not examine their breasts, 2) the influence of their upbringing, 3) information or education previously received about the method of examination, and 4) other types of self-care. The findings were summarized under the following categories: feelings, experiences, and lifestyle. Anxiety/fear of discovering a lump and faith/trust in one's own ability to perform the examination were dominating factors influencing the practice or non-practice of BSE. However, there was a general need for knowledge, theoretical as well as practical, among the women studied. They also needed help to identify a strategy to enable them to remember to perform the examination. In order to make BSE a habit, education about BSE ought to be provided to girls at school. The important role of nurses in teaching women to examine their breasts themselves and in reminding them to perform the examination was emphasized.

Adult↗
PubMed1997

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.

Female↗
PubMed1997

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.

Amoxicillin↗
PubMed1997

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.

Animals↗
PubMed1996

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.

Animals↗
PubMed1996

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.

Animals↗
PubMed1996

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.

Animals↗
PubMed1996

Chlamydial antibodies in women who suffer miscarriage.

OBJECTIVE: To ascertain the relation between previous chlamydial infection and miscarriage. DESIGN: A prospective study of 349 women who had a miscarriage. PARTICIPANTS: Women surgically treated for spontaneous pregnancy loss on an outpatient basis at a hospital. SUBJECTS: Three hundred and forty-nine women who miscarried, of whom 91 had at least one previous miscarriage and 33 had had two or more miscarriages previously. Age-matched women who had a normal pregnancy served as controls. INTERVENTIONS: Blood samples were drawn from patients and controls for antibody determination. MAIN OUTCOME MEASURES: Patients and controls were compared regarding the frequency of Chlamydia trachomatis IgG antibodies (titre > or = 1/32). Antibodies to C. pneumoniae were also analysed to study cross reactivity. RESULTS: The frequency of IgG antibodies among the patients was 137/349 (39.3%) which was not statistically different from that among controls (116/349; 33.2%). Even among those who had miscarried previously the antibody frequencies did not differ significantly between patients and controls. The rate of C. trachomatis antibodies was about the same whether or not antibodies to C. pneumoniae were present in both patients and controls. CONCLUSION: No association was found serologically between previous chlamydial infection and miscarriage and no significant cross reactivity between C. pneumoniae and C. trachomatis could be detected.

Abortion, Spontaneous↗
PubMed1996

Micturition in conscious rats with and without bladder outlet obstruction: role of spinal alpha 1-adrenoceptors.

1. In normal rats and rats with bladder hypertrophy secondary to outflow obstruction, undergoing continuous cytometry, we examined the responses to the selective alpha 1-adrenoceptor antagonist doxazosin given intrathecally (i.t.) and intra-arterially (i.a.). In addition, we investigated the effects of the drug on L-dopa-induced bladder hyperactivity in normal, unobstructed rats. 2. Doxazosin 50 nmol (approximately 60 micrograms kg-1), given i.t., decreased micturition pressure in normal rats and in animals with post-obstruction bladder hypertrophy. The effect was much more pronounced in the animals with hypertrophied/overactive bladders. Doxazosin did not markedly affect the frequency or amplitude of the unstable contractions observed in obstructed rats. In contrast, however, doxazosin reduced L-dopa-induced bladder overactivity. When tested, the enantiomers of doxazosin produced qualitatively similar effects to doxazosin, but there was no evidence of stereoselectivity. 3. The results suggest that in addition to the well documented action on prostatic and lower urinary tract smooth muscle, and an effect on the sympathetic outflow to the bladder, bladder neck, prostate, and external urethral sphincter, doxazosin may have an action at the level of the spinal cord and ganglia, thereby reducing activity in the parasympathetic nerves to the bladder. This effect is more pronounced in rats with bladder hypertrophy than in normal rats.

Adrenergic alpha-Antagonists↗
PubMed1996

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.

Animals↗
PubMed1996

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.

Angiotensin II↗