Relationship of Ureaplasma urealyticum biovar 2 to nongonococcal urethritis.

The aim of this study was to determine the frequency of Ureaplasma urealyticum biovars 1 and 2 among 340 men with or without nongonococcal urethritis (NGU) attending a venereal disease clinic in Sweden. NGU was defined by the presence of at least four polymorphonuclear leukocytes per microscopic field (x1,000 magnification) on a smear in which Neisseria gonorrhoeae could not be detected. Ureaplasma urealyticum was detected by polymerase chain reaction, and biovar determination was performed directly on the amplicons by liquid hybridization with biovar-specific probes. Patients with NGU were younger, had had more sexual partners, and exhibited symptoms of urethritis more often than patients without NGU. Ureaplasma urealyticum was detected with the same frequency among patients with and among those without NGU. Among patients with NGU, Ureaplasma urealyticum-positive men were more frequently symptomatic than Ureaplasma urealyticum-negative men. Among patients without NGU, Ureaplasma urealyticum-positive men had had more sexual partners than Ureaplasma urealyticum-negative men. Ureaplasma urealyticum biovar 2 was detected more often among patients with NGU than among those without (P=0.012). Logistic regression analysis was performed using detection of biovar 2 as the response variable and the following four variables as explanatory variables: presence or absence of NGU, symptoms of urethritis, number of partners, and age < or = 24 years. The only association found was that between Ureaplasma urealyticum biovar 2 and age < or = 24 years. More studies should be conducted to determine the possible pathogenic impact of Ureaplasma urealyticum biovar 2.

Importance of transmembrane segment M3 of the sarcoplasmic reticulum Ca2+-ATPase for control of the gateway to the Ca2+ sites.

The specific functional roles of various parts of the third transmembrane segment (M3) of the sarcoplasmic reticulum Ca(2+)-ATPase were examined by functionally characterizing a series of mutants with multiple or single substitutions of M3 residues. Steady-state and transient kinetic measurements, assisted by computer simulation of the time and Ca(2+) dependences of the phosphorylation level, were used to study the partial reaction steps of the enzyme cycle, including the binding and dissociation of Ca(2+) at the high affinity cytoplasmically facing sites. The mutation Lys-Leu-Asp-Glu(255) --> Glu-Ile-Glu-His resulted in a conspicuous increase in the rate of Ca(2+) dissociation as well as a displacement of the major conformational equilibria of the phosphoenzyme and dephosphoenzyme forms. The point mutant Phe(256) --> Ala also showed an increased rate of Ca(2+) dissociation, whereas a conspicuous decrease both in the rate of Ca(2+) dissociation and in the rate of Ca(2+) binding was found for the mutant Gly-Glu-Gln-Leu(260) --> Ile-His-Leu-Ile. These findings suggest that the NH(2)-terminal half of M3 is involved in control of the gateway to the Ca(2+) sites. The main effect of two mutations to the COOH-terminal half of M3, Ser-Lys-Val-Ile-Ser(265) --> Thr-Gly-Val-Ala-Val and Leu-Ile-Cys-Val-Ala-Val-Trp-Leu-Ile(274) --> Phe-Leu-Gly-Val-Ser-Phe-Phe-Ile-Leu, was a block of the dephosphorylation.

Relationship of Ureaplasma urealyticum biovars to the presence or absence of bacterial vaginosis in pregnant women and to the time of delivery.

In a nested case-control study, the occurrence of Ureaplasma urealyticum in cervical specimens from 84 women with idiopathic preterm delivery and from 400 women delivering at term was investigated. The two potential risk factors for preterm delivery, colonization with Ureaplasma urealyticum and bacterial vaginosis, were found to be interdependent variables. The association between these factors and preterm delivery was assessed by regression analysis. Neither colonization with Ureaplasma urealyticum (odds ratio [OR] 0.7, 95% confidence interval [CI] 0.4-1.2) nor bacterial vaginosis (OR 0.8, 95% CI 0.3-1.8) was associated with preterm delivery. In women who delivered preterm, biovar 2 was found significantly more often in those with the clinical diagnosis of bacterial vaginosis (43%) than in those without (5%) (OR 15, 95% CI 1.2-209).

Detection of Ureaplasma urealyticum by PCR and biovar determination by liquid hybridization.

An assay which combines the direct detection of Ureaplasma urealyticum with biovar determination was developed and applied to 618 urogenital specimens. U. urealyticum was detected by inhibitor-controlled PCR. A 429-bp fragment of the urease gene was amplified. The amplicons were labelled with digoxigenin during PCR. Biovar determination was performed by liquid hybridization with biotin-labelled biovar-specific probes, and the hybrids were detected with peroxidase-conjugated sheep anti-digoxigenin immunoglobulin G Fab fragments. Results of PCR and culture for 453 urogenital specimens from women and 105 urethral specimens from men could be compared. Among the specimens from women, 63% were PCR positive as well as culture positive, 0.9% were positive only by PCR, and 4% were positive only by culture. Among the specimens from men, 15% were PCR positive as well as culture positive, 1% were positive only by PCR, and 9% were positive only by culture. By using culture as the reference method, the PCR had a sensitivity of 94% and a specificity of 98% when applied to specimens from women and a sensitivity of 64% and a specificity of 99% when applied to specimens from men. Overall, 80% of the PCR-positive specimens contained biovar 1,13.5% contained biovar 2, and 6.5% contained both biovars.