Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden

A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.

Genetic diversity of allozymes in turnip (Brassica rapa L. var. rapa) from the Nordic area

Genetic diversity and relationships based on isozymes were studied in 31 accessions of turnip (Brassica rapa L. var. rapa). The material included varieties, elite stocks, landraces and older turnip of slash-and-burn type from the Nordic area. A total of 9 isozyme loci and 26 alleles were studied. The isozyme systems were ACO, DIA, GPI, GOT, PGM, PGD and SKD. The level of heterozygosity was reduced in the landraces, but it was high for the variety group 'Ostersundom'. Turnip has a higher genetic variation than other crops within B. rapa and than in other species with the same breeding system. The genetic diversity showed that 18.7% of the genetic variation was within the accessions, and the total H tau value was 0.358. Gpi-I and Pgd-I showed the lowest variation compared with the other loci. The cluster analysis revealed five clusters, with one main cluster including 25 of the 31 accessions. The dendrogram indicated that the variety group 'Ostersundom' clustered together whereas the variety group 'Bortfelder' was associated with country of origin. The landraces were spread in different clusters. The 'slash-and-burn' type of turnip belonged to two groups.

Perioperative hypothermia and postoperative opioid requirements

BACKGROUND AND OBJECTIVE

Hypothermia may alter the disposition of opioids. Because opioids are commonly used as analgesics in the postoperative period, it is of clinical interest to clarify whether perioperatively developed hypothermia affects postoperative opioid requirements.

METHODS

Fifty-nine patients undergoing subtotal hysterectomy were prospectively randomized and either treated intraoperatively with forced air warming, or served as controls covered with conventional blankets without active warming. Both groups received postoperative patient-controlled analgesia with the opioid ketobemidone. Total analgesic requirements, demands, analgesic requirements over 6-h intervals and pain scores were measured for 48 h. Core temperature at the tympanic membrane and ambient room temperature were measured during the perioperative period.

RESULTS

There were no postoperative differences in analgesic requirements or pain intensity between normothermic and hypothermic patients. Patients treated with warm air had an up to 1 degree C higher core temperature from 0.5 h after anaesthesia induction until almost 2 h postoperatively. The actively warmed patients also had a lower intraoperative blood loss than the hypothermic patients (186 +/- 27 mL vs. 308 +/- 47 mL; P < 0.05).

CONCLUSION

In a clinical setting, opioid requirements do not seem to be affected by mild postoperative hypothermia after lower abdominal surgery.

Staphylococcus aureus induces release of bradykinin in human plasma

Staphylococcus aureus is a prominent human pathogen. Here we report that intact S. aureus bacteria activate the contact system in human plasma in vitro, resulting in a massive release of the potent proinflammatory and vasoactive peptide bradykinin. In contrast, no such effect was recorded with Streptococcus pneumoniae. In the activation of the contact system, blood coagulation factor XII and plasma kallikrein play central roles, and a specific inhibitor of these serine proteinases inhibited the release of bradykinin by S. aureus in human plasma. Furthermore, fragments of the cofactor H-kininogen of the contact system efficiently blocked bradykinin release. The results suggest that activation of the contact system at the surface of S. aureus and the subsequent release of bradykinin could contribute to the hypovolemic hypotension seen in patients with severe S. aureus sepsis. The data also suggest that the contact system could be used as a target in the treatment of S. aureus infections.

Pre-school children with developmental co-ordination disorder: self-perceived competence and group motor skill intervention

OBJECTIVE

To investigate self-perceived competence in 5- to 6-y-old children with developmental co-ordination disorder.

SUBJECTS AND METHODS

Scores in two scales of self-perceived competence were compared between a study group of children with developmental co-ordination disorder (n = 37) and a reference group (n = 60). In addition, effects of group motor skill intervention were evaluated by comparing scores in study group children randomly allocated to an intervention (n = 17) and a control subgroup (n = 20). The intervention subgroup received intervention once weekly for 10 wk.

CONCLUSIONS

Pre-school children with developmental co-ordination disorder are similar to peers of the same age regarding self-perception of their own competence in areas concerning school, peer relations and motor skills. The change in score in the perceived motor competence scale was significantly greater in the intervention than in the control subgroup, suggesting that the intervention increased individual awareness of motor competence.

Effects of diabetes on neurotransmission in rat vaginal smooth muscle

The aim of this work was to characterize the effect of experimental diabetes on neurotransmission in rat vagina. Female Sprague-Dawley rats were divided into two groups: non-diabetic controls (NDM, n=38) and diabetics (DM, n=38). DM was produced by intraperitoneal injection of streptozotocin. Eight weeks later the animals were killed, the distal part of the vagina was removed, and smooth muscle strips were prepared for functional organ bath experiments and for measurement of nitric oxide synthase (NOS) activity. In DM preparations, the EC(50) value for noradrenaline (NA) was significantly increased (P<0.05) and the maximal contractile response decreased (P=0.001). In preparations precontracted with NA, the NO donor SNAP and calcitonin gene-related peptide (CGRP) caused concentration-dependent relaxations, which were significantly decreased (P<0.001) in the DM group. Electrical stimulation of nerves (EFS) caused frequency-dependent contractions, which were significantly lower in DM than in NDM strips (P<0.001). SNAP and CGRP concentration-dependently inhibited EFS evoked contractions in both NDM and DM preparations. The inhibition was significantly lower (P<0.05) in the DM group. In NDM preparations precontracted with NA, EFS evoked frequency-dependent relaxations; such relaxations were inhibited or reduced in DM. Treatment with the NOS inhibitor, L-NOARG 0.1 mM, abolished relaxations in all preparations or produced contraction in DM preparations. Calcium-dependent NOS activity was not significantly different in the DM and NDM groups. However, the DM animals showed a small but significant increase in calcium-independent NOS-activity (P<0.05). Diabetes interferes with adrenergic-, cholinergic- and NANC-neurotransmitter mechanisms in the smooth muscle of the rat vagina. The changes in the nitrergic neurotransmission are not due to reduction in NOS-activity, but seem to be due to interference with later steps in the L-arginine/NO/guanylate cyclase/cGMP system.

The effectiveness of routine health examinations at 2, 6, 9 and 12 months of age: experiences based on data from a Swedish county

AIM

The aim of this study was to elucidate the role of health surveillance for infants during the first year of life in detecting severe health problems. Two central questions were addressed: (1) what health problems were detected by routine health examinations at the Child Health Centre at the 2-, 6- and 12-month check-ups by a physician and at the 9-month check-up by a nurse; and (2) to what extent did the health examinations contribute to early identification of children with following key abnormalities: congenital heart disease, congenital dislocation of the hip, abnormalities as registered at the habilitation centre and severe hearing impairments? MATERIAL AND INCLUSION CRITERIA: The study population included all children in Uppsala county, born January 1995 to October 1996, who had participated in at least one of the four health check-ups. There were 3107-3487 children in the respective check-ups.

METHOD

Data from a county health register as well as child health records and information regarding referrals were analysed to categorize the health problems by type, severity and action taken. Data on children with key abnormalities were obtained from specialist units.

RESULTS

The rate of suspected new health problems varied between 1.9% and 2.8% at the respective check-ups. Of the new problems detected by the physician, 21%-36% were false-positive, 34%-44% were minor and 10%-15% were moderate. Only two severe health problems were detected among all the children during the four check-ups. Of all key abnormalities, 20% were detected by way of child health surveillance during the first year of life.

IMPLICATIONS

Severe health problems and key abnormalities in infants were detected only to a limited extent through routine health examinations at 2, 6, 9 and 12 months of age. The minor and moderate problems detected justify a health surveillance programme, but the organization and content of the programme could be reconsidered.

Escherichia coli-induced inducible nitric oxide synthase and cyclooxygenase expression in the mouse bladder and kidney

BACKGROUND

The host response to urinary tract infection includes the production of different inflammatory mediators. We investigated the cellular localization and time course of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) expression in the mouse bladder and kidney after bacterial infection.

METHODS

Experimental urinary tract infection in mice was established by intravesical inoculation of a clinical uropathogen Escherichia coli (E. coli) AD 110. Urine was collected at 6-, 12-, 24-, and 72-hours postinstillation, and the nitrite concentration was determined. The induction of iNOS and COX-2 was studied by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Nitrite levels in the urine had increased threefold at 6 and 12 hours postbacterial instillation. Bladders from mice instilled with AD 110, but not with phosphate-buffered saline, showed a large number of iNOS-- and COX-2--expressing inflammatory cells. The inflammatory cell activation peaked at 6 and 12 hours postinstillation and had vanished by 72 hours. iNOS expression was detected in some urothelial cells after 24 and 72 hours, but COX-2 expression was not detected. In the kidney, infection activated an iNOS and COX-2 response, as shown by immunoreactivity in inflammatory cells at all time points. A strong epithelial iNOS response was observed in the renal pelvis at 12, 24, and 72 hours postinstillation, but COX-2 was not detected. Enhanced tissue expression of iNOS and COX-2 after bacterial instillation was also demonstrated by RT-PCR.

CONCLUSIONS

E. coli AD 110 induced expression of iNOS and COX-2 in the urinary tract. Inflammatory cells expressed both iNOS-and COX-2, but epithelial cells expressed only iNOS and with a later onset than in the inflammatory cells. This suggests that the epithelial iNOS response is not caused by direct bacterial activation, but more likely is by mediators involved in the inflammatory response.

Current infection with Helicobacter pylori, but not seropositivity to Chlamydia pneumoniae or cytomegalovirus, is associated with an atherogenic, modified lipid profile

Infectious agents may be involved in atherothrombogenesis. The potential pathogenic pathway, however, remains unclear. We investigated the association between various infectious agents and lipoproteins known to have an atherogenic effect. We recruited 470 healthy blood donors and 238 patients with angiographically proven coronary heart disease (CHD), aged 40 to 68 years. Seropositivity to Chlamydia pneumoniae (CP), chlamydial lipopolysaccharide, and cytomegalovirus (CMV) was determined; infection with Helicobacter pylori (HP) was assessed by using the [(13)C]urea breath test. In all subjects, total cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), and various apolipoproteins (apos) were determined. In unadjusted analysis, mean HDL cholesterol concentration was significantly decreased in HP-positive healthy subjects (1.36 vs 1.44 mmol/L, P=0.006) compared with HP-negative subjects. The HDL cholesterol to total cholesterol ratio was significantly decreased in HP-positive (0.259 vs 0.276, P=0.01) and CP-seropositive (0.266 vs 0.280, P=0.04) healthy subjects compared with (sero)negatives. Mean apoAI levels were significantly lower in HP-positive healthy subjects (1.46 vs 1.51 g/L, P=0.03) and in CMV-positive healthy subjects (1.47 vs 1.52 g/L, P=0.01) compared with (sero)negative subjects. After multivariable adjustment by means of linear regression analysis, only the association between HP infection and decreased HDL cholesterol (P=0.002), decreased HDL cholesterol to total cholesterol ratio (P:=0.005), decreased apoAI (P=0.02), and increased apoB (P=0.02) persisted and remained significant. There was no independent association between other lipoproteins and serological markers of CP or CMV infection. Current infection with HP, but not seropositivity to CP or CMV, was associated with an atherogenic, modified lipid profile. These lipid alterations could explain, at least in part, the reported weak association between chronic HP infection and atherosclerotic diseases.

Three-dimensional structures of MHC class I-peptide complexes: implications for peptide recognition

Over the last decade, the number of crystal structures of major histocompatibility complex (MHC) class I-peptide complexes has increased rapidly. These studies have provided unique and fascinating insights into the structural basis of MHC-peptide interactions and the specificity of peptide recognition by MHC class I molecules.

Multicenter comparison trial of DNA extraction methods and PCR assays for detection of Chlamydia pneumoniae in endarterectomy specimens

The reported rate of detection of Chlamydia pneumoniae DNA within atherosclerotic lesions by PCR varies between 0 and 100%. In this study, identical sets of coded experimental atheroma samples (n = 15) and spiked controls (n = 5) were analyzed by 16 test methods in nine centers by means of PCR. The positive controls were correctly identified to levels of 1, 0.1, and 0.01 inclusion bodies of C. pneumoniae/ml of tissue homogenate by 16 (100%), 11 (69%), and 3 (19%) of the test methods, respectively. Three out of 16 negative controls (19%) were rated positive. Positivity rates for atheroma samples varied between 0 and 60% for the different test methods, with the maximum concordant result for positivity being only 25% for one carotid artery sample. There was no consistent pattern of positive results among the various laboratories, and there was no correlation between the detection rates and the sensitivity of the assay used.

Crystal structure of the retaining galactosyltransferase LgtC from Neisseria meningitidis in complex with donor and acceptor sugar analogs

Many bacterial pathogens express lipooligosaccharides that mimic human cell surface glycoconjugates, enabling them to attach to host receptors and to evade the immune response. In Neisseria meningitidis, the galactosyltransferase LgtC catalyzes a key step in the biosynthesis of lipooligosaccharide structure by transferring alpha-d-galactose from UDP-galactose to a terminal lactose. The product retains the configuration of the donor sugar glycosidic bond; LgtC is thus a retaining glycosyltranferase. We report the 2 A crystal structures of the complex of LgtC with manganese and UDP 2-deoxy-2-fluoro-galactose (a donor sugar analog) in the presence and absence of the acceptor sugar analog 4'-deoxylactose. The structures, together with results from site-directed mutagenesis and kinetic analysis, give valuable insights into the unique catalytic mechanism and, as the first structure of a glycosyltransferase in complex with both the donor and acceptor sugars, provide a starting point for inhibitor design.

Activation of the transcription factors nuclear factor-kappaB and activator protein-1 in bladder smooth muscle exposed to outlet obstruction and mechanical stretching

PURPOSE

Transcriptional control of bladder genes in response to outlet obstruction, growth factors and mechanical force is poorly understood. We analyzed the effects of bladder obstruction, mechanical stretching and platelet derived growth factor on the activation of the major growth controlling transcription factors nuclear factor-kappaB and activator protein-1.

MATERIALS AND METHODS

Complete outlet obstruction was created in female rats by proximal urethral ligation and bladders were harvested 3, 6 and 24 hours later, respectively. Bladder cells were grown in culture and stimulated with 10 ng./ml. platelet derived growth factor or 10 cycles per minute of mechanical stretching for 0.5 to 4 hours. Nuclear proteins were high salt extracted and incubated with 32phosphorus double strand oligonucleotides containing a consensus binding sequence for activator protein-1 or nuclear factor-kappaB. The resulting DNA protein complexes were analyzed by electrophoretic mobility shift assay.

RESULTS

Nuclear extract isolated from obstructed bladders showed intense activator protein-1 binding activity 3, 6 and 24 hours after obstruction as well as increased nuclear factor-kappaB binding activity after 6 and 24 hours. Binding activity was absent or minimal in sham operated rats. Cultured cells exposed to mechanical stretching for 2 and 4 hours showed increased activator protein-1 and nuclear factor-kappaB DNA binding compared with unstretched cells. Likewise stimulation with platelet derived growth factor caused a consistent increase in activator protein-1 and nuclear factor-kappaB binding activity. The binding of nuclear proteins was abolished by a 40-fold excess of an unlabeled specific oligonucleotide but not by excess irrelevant oligonucleotide. Thus, the assays were specific for the factors involved.

CONCLUSIONS

Bladder obstruction and mechanical stretching cause the formation of activator protein-1 and nuclear factor-kappaB DNA complexes, consistent with a role of these transcription factors in the control of hypertrophy associated gene activation.

Crystallization and preliminary X-ray study of pig liver dihydropyrimidine dehydrogenase

Dihydropyrimidine dehydrogenase catalyzes the first and rate-limiting reaction in pyrimidine catabolism. The enzyme contains one FMN, one FAD and four Fe-S clusters per subunit of 1025 amino acids as prosthetic groups. It is also the major determinant of bioavailability and toxicity of 5-fluorouracil, a chemotherapeutic agent widely used in the treatment of solid tumors. Crystals of this enzyme diffracting to at least 2.5 A have been obtained by the hanging-drop vapour-diffusion method and belong to space group P2(1) (unit-cell parameters a = 82.0, b = 159.3, c = 163.6 A, beta = 96.1 degrees ), with two homodimers per asymmetric unit.

Severe lung lesions caused by Salmonella are prevented by inhibition of the contact system

Vascular damage induced by trauma, inflammation, or infection results in an alteration of the endothelium from a nonactivated to a procoagulant, vasoconstrictive, and proinflammatory state, and can lead to life-threatening complications. Here we report that activation of the contact system by Salmonella leads to massive infiltration of red blood cells and fibrin deposition in the lungs of infected rats. These pulmonary lesions were prevented when the infected animals were treated with H-D-Pro-Phe-Arg-chloromethylketone, an inhibitor of coagulation factor XII and plasma kallikrein, suggesting that inhibition of contact system activation could be used therapeutically in severe infectious disease.

Reduced GLP-1 and insulin responses and glucose intolerance after gastric glucose in GRP receptor-deleted mice

By applying a newly developed ELISA technique for determining biologically active intact glucagon-like peptide [GLP-1, GLP-1-(7-36)amide] in mouse, plasma baseline GLP-1 in normal NMRI mice was found to be normally distributed (4.5 +/- 0.3 pmol/l; n = 72). In anesthetized mice, gastric glucose (50 or 150 mg) increased plasma GLP-1 levels two- to threefold (P < 0.01). The simultaneous increase in plasma insulin correlated to the 10-min GLP-1 levels (r = 0.36, P < 0.001; n = 12). C57BL/6J mice deleted of the gastrin-releasing peptide (GRP) receptor by genetic targeting had impaired glucose tolerance (P = 0.030) and reduced early (10 min) insulin response (P = 0.044) to gastric glucose compared with wild-type controls. Also, the GLP-1 response to gastric glucose was significantly lower in the GRP receptor-deleted mice than in the controls (P = 0.045). In conclusion, this study has shown that 1) plasma levels of intact GLP-1 increase dose dependently on gastric glucose challenge in correlation with increased insulin levels in mice, and 2) intact GRP receptors are required for normal GLP-1 and insulin responses and glucose tolerance after gastric glucose in mice.

Nitric oxide donors and angiotensin-converting enzyme inhibitors act in concert to inhibit human angiotensin-converting enzyme activity and platelet aggregation in vitro

This study investigates the effects of exogenous and endogenous nitric oxide (NO) on human circulating and endothelial angiotensin-converting enzyme activity and platelet aggregation. The NO donor S-nitroso-N-acetylpenicillamine (10(-8)-10(-6) M) significantly and dose-dependently inhibited serum angiotensin-converting enzyme activity. The concomitant addition of S-nitroso-N-acetylpenicillamine to angiotensin-converting enzyme inhibitor-treated (captopril or enalaprilat) serum, further reduced angiotensin-converting enzyme activity. In cultured endothelial cells from human umbilical veins (HUVECs), both S-nitroso-N-acetylpenicillamine and 3-morpholinosydnonimine (SIN-1) significantly reduced angiotensin-converting enzyme activity. An additative effect was seen with a combined treatment of captopril and S-nitroso-N-acetylpenicillamine. Treatment with the NO synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) did not affect angiotensin-converting enzyme activity. Thrombin inhibited endothelial angiotensin-converting enzyme activity, an effect that was abolished when cells were pretreated with L-NMMA. Adenosine 5'-diphosphate (ADP)-induced platelet aggregation was inhibited with S-nitroso-N-acetylpenicillamine, SIN-1 and nitroglycerine. Captopril did not affect aggregation, while a high concentration of enalaprilat (10(-4) M) reduced it. The concomitant addition of 10(-5) M angiotensin-converting enzyme inhibitor to NO donor-treated platelets resulted in a further reduction of platelet aggregation. This effect was most evident with SIN-1 and enalaprilat. In conclusion, both exogenous and endogenous NO inhibit human angiotensin-converting enzyme activity. NO donors and angiotensin-converting enzyme inhibitors act in concert to inhibit angiotensin-converting enzyme and platelet aggregation.

MYB oncogene amplification in hereditary BRCA1 breast cancer

Comparative genomic hybridization analysis has demonstrated that breast tumors from BRCA1 and BRCA2 germ-line mutation carriers contain a large number of chromosomal copy number gains and losses. A high regional copy number gain at 6q22-q24 was observed in one BRCA1 tumor, and fluorescence in situ hybridization analysis indicated a strong amplification of the MYB oncogene (15 copies of MYB compared with 1 copy of chromosome 6 centromere). Fluorescence in situ hybridization analysis revealed amplification of MYB in 5 (29%) of 17 BRCA1 breast tumors, whereas none of 8 BRCA2 tumors and 13 breast cancer cell lines, and only 2 of 100 sporadic breast tumors exhibited altered MYB copy numbers. Gene amplification resulted in mRNA overexpression as determined by Northern blot and cDNA microarray analysis, and protein overexpression by immunohistochemical staining. We conclude that MYB amplification is infrequent in sporadic breast cancer but common in breast tumors from BRCA1 mutation carriers, suggesting a role of this cell cycle regulator and transcription factor in the progression of some BRCA1 tumors. However, we cannot rule out the significance of other genes in the 6q22-q24 amplicon.

Comparison of five serologic tests for diagnosis of acute infections by Chlamydia pneumoniae

Serology is often used to diagnose acute infections by Chlamydia pneumoniae. In this study paired sera from patients with acute respiratory tract infection during an epidemic of C. pneumoniae infections were examined by five different antibody tests. These tests were the complement fixation (CF) test, the microimmunofluorescence (MIF) test, a recombinant enzyme immunoassay (rEIA) (Medac) based on a recombinant lipopolysaccharide of chlamydia and measuring antibodies to a common chlamydial antigen, and two tests that utilize preparations of C. pneumoniae organisms, the SeroCp-EIA (Savyon) (with preserved lipopolysaccharide) and the LOY-EIA (Labsystems) (without this antigen). Both of the last two tests should measure specific antibodies to C. pneumoniae, although cross-reacting antibodies may also be detected by the SeroCp-EIA. Acute infection of C. pneumoniae was serologically confirmed in 44% of the cases by at least two different tests. Using an expanded "gold standard," i.e., the presence of significant reactions in at least two tests, the sensitivity of the CF test was 69%, that of the MIF test was 88%, that of the rEIA was 89%, that of the LOY-EIA was 96%, and that of the SeroCp-EIA was 92%. Specificity was high for all methods, but adjustments of diagnostic criteria were made to several of the tests. The basis for these adjustments and supportive data are presented. Infections of C. pneumoniae were detected in patients from 8 to 83 years of age. Two peaks in the incidence of such infections were observed: one among young teenagers and a second in adults 30 to 45 years of age, corresponding to parents of young teen-agers. The tests were equally sensitive in different age groups. Reinfections seemed to be rare.

Functional characteristics of urinary tract smooth muscles in mice lacking cGMP protein kinase type I

Nitric oxide (NO)-mediated smooth muscle relaxation is mediated by cGMP through activation of cGMP-dependent protein kinase I (cGKI). We studied the importance of cGKI for lower urinary tract function in mice lacking the gene for cGKI (cGKI-/-) and in litter-matched wild-type mice (cGKI+/+) in vitro and in vivo. cGKI deficiency did not result in any changes in bladder gross morphology or weight. Urethral strips from cGKI-/- mice showed an impaired relaxant response to nerve-derived NO. The cGMP analog 8-bromo-cGMP (8-BrcGMP) and the NO-donor SIN-1 relaxed the wild-type urethra (50-60%) but had only marginal effects in the cGKI-deficient urethra. Bladder strips from cGKI-/- mice responded normally to electrical field stimulation and to carbachol but not to 8-BrcGMP. In vivo, the cGKI-deficient mice showed bladder hyperactivity characterized by decreased intercontraction intervals and nonvoiding bladder contractions. Loss of cGKI abolishes NO-cGMP-dependent relaxations of urethral smooth muscle and results in hyperactive voiding. These data suggest that certain voiding disturbances may be associated with impaired NO-cGKI signaling.

Purification, crystallization and preliminary crystallographic data for rat cytosolic selenocysteine 498 to cysteine mutant thioredoxin reductase

Mammalian cytosolic thioredoxin reductase is a homodimer of 55 kDa subunit containing an essential penultimate selenocysteine residue. An active analogue of the rat enzyme in which cysteine replaces selenocysteine has been expressed in Escherichia coli cells at high levels and purified to homogeneity. The pure enzyme contains one FAD per subunit and shows spectral properties identical to that of the wild-type thioredoxin reductase. The isolated enzyme in its oxidized and reduced forms or the enzyme complexed with NADP(+) was crystallized by the hanging-drop vapour-diffusion method. The diffraction pattern extends to 3 A resolution. The crystals are monoclinic, space group P2(1), with unit-cell parameters a = 78.9, b = 140.5, c = 170.8 A, alpha = 94.6 degrees. There are three dimeric molecules in the asymmetric unit.

Endothelial dysfunction after repeated Chlamydia pneumoniae infection in apolipoprotein E-knockout mice

BACKGROUND

Arterial relaxation is largely regulated by endothelial nitric oxide (NO). Its diminished activity has been associated with incipient atherosclerosis. We investigated the endothelium-dependent relaxation of aorta in apolipoprotein E-knockout (apoE-KO) mice exposed to single or repeated Chlamydia pneumoniae inoculation.

METHODS AND RESULTS

Forty-eight apoE-KO mice, 8 weeks old, were inoculated intranasally with C pneumoniae (n=24) or saline (n=24) every 2 weeks over a 6-week period. Twenty mice (10 infected and 10 controls) were killed at 2 weeks and 6 weeks, respectively, after the first inoculation. The smooth muscle tone of aortic rings was measured in vitro at both time points. The norepinephrine-precontracted thoracic aortic rings were successively exposed to methacholine in the absence and presence of N:(G)-nitro-L-arginine methyl ester (L-NAME) and diclofenac. The methacholine-induced relaxation was attenuated in the infected mice at 6 weeks in both the absence and presence of L-NAME (P:<0.05 and P:<0.01, respectively). When administered together with L-NAME, diclofenac enhanced the relaxation of the L-NAME-pretreated aortas in infected mice at 2 weeks (P:<0.05) but not in noninfected mice. The relaxation response from infected mice tended to differ in the same manner at 6 weeks (P:<0.1). No intimal thickening was detected at either time point.

CONCLUSIONS

C pneumoniae impairs arterial endothelial function, and the NO pathway is principally involved. Cyclooxygenase-dependent vasoconstricting products may also account for the infection-induced impaired relaxation. These findings further support the role of C pneumoniae infection in atherosclerosis development.

Nitric oxide-induced cGMP accumulation in the mouse bladder is not related to smooth muscle relaxation

The functional role of nitric oxide (NO) and the guanylate cyclase/cGMP second messenger system was investigated in the mouse bladder. Electrical field stimulation and the NO-donor 3-morpholino-sydnonimin hydrochloride (SIN-1) did not induce relaxation of the carbachol-precontracted bladder. However, sodium nitroprusside (10(-3) M) was found to enhance the contractile response to electrical field stimulation by 24+/-6% (n=8; P<0.05) without affecting the contractile response to carbachol. The enhancement of bladder contractility evoked by sodium nitroprusside was inhibited by the guanylate cyclase inhibitor 1H-[1,2, 4]oxadiazolo[4,3-a]quinoxalime-1-one (ODQ; 10(-6) M). Incubation of bladder strips with SIN-1 and sodium nitroprusside caused an increase in cGMP accumulation as measured by radioimmunoassay. Immunohistochemical studies showed cGMP-immunoreactivity in nerve fibres and in stromal cells, but not in smooth muscle bundles after exposure to NO-donors. The results show that NO-donors have no inhibitory effect on smooth muscle tone in the mouse bladder, but that NO may have a functional role as an excitatory neuromodulator. The targets of endogenous NO in the bladder may be the demonstrated cGMP-positive structures, i.e., nerves and stromal cells.

Assessing the allozyme variation in cultivars and Swedish landraces of rye (Secale cereale L.)

Genetic interpretation and diversity of 9 isozyme loci have been estimated in 7 improved varieties and 19 landraces from Sweden by means of starch gel electrophoresis. The isozyme systems were ACO, DIA, GPI, MDH, PGD and PGM. For the statistic analysis we used the following measures: average number of alleles per locus, percentage of polymorphic loci, average heterozygosity direct count and average heterozygosity Hardy-Weinberg expected unbiased estimate. The measures were made on species and population levels. The distribution of the total genetic diversity among populations was also calculated. To illustrate the genetic relationships among populations, genetic distances were measured and principal component analysis performed. As expected in a cross-pollinated crop we found high genetic diversity and a larger variation within than among the populations. Somewhat unexpectedly, however, we found that the currently used varieties have the same high level of heterozygosity as the landraces but in the dendrogram the two groups are separated. The dendrogram showed three main clusters. The large cluster included 21 populations and the two small clusters were clearly distinguishable from the rest. The landrace spring-type could not be separated from the landraces winter-type, but we did detect a difference between different spring types. A few populations had unique alleles for certain loci.