The pathogenesis of gonococcal urethritis in men: confocal and immunoelectron microscopic analysis of urethral exudates from men infected with Neisseria gonorrhoeae

Confocal and immunoelectron microscopic analysis of urethral exudates from 12 men with gonococcal urethritis showed that Neisseria gonorrhoeae can invade urethral epithelial cells. Studies with acridine orange stain demonstrated that the majority of organisms within urethral epithelial cells were viable at the time of fixation. Three-dimensional modeling of an infected epithelial cell using image analysis of 21 digitized confocal sections stained with YOYO-1 and DiIC 18(3) revealed that gonococcal invasion of these cells occurred in a polar fashion, most likely at the epithelial luminal surface. Serial immunoelectron micrographs showed evidence of membrane fusion with pedestal formation between the gonococcus and the epithelial cell, gonococci within vacuoles, and occasional gonococci free in the cytoplasm. Immunoelectron microscopy studies showed ruptured vacuoles at the cell surface releasing organisms. These studies demonstrate that urethral epithelial cells are invaded by gonococci during the course of infection in males.     

Gonorrhoea in the asymptomatic patient: presentation and the role of contact tracing for heterosexual men and women and for homosexual men

Clinically silent gonorrhoea is the major problem in the control of the disease. Only 12 per cent of infected women reported in 1974 because of symptoms, compared with 97 per cent of infected heterosexual men and only 35 per cent of homosexual men with gonococcal proctitis alone. Homosexual men, compared with heterosexual men, had twice as many subsequent sexual contacts after infection and had a higher incidence of early syphilis. Eighty-four per cent had experienced passive anorectal intercourse. Ninety-seven per cent of men with gonococcal urethritis reported because of symptoms, but occasionally (particularly after unsuccessful treatment) urethral gonorrhoea in men may be clinically silent and even require tests of the overnight urethral secretion for diagnosis. For women, and for homosexual men who have had passive anorectal (or oral) intercourse, the indication for attendance for tests for gonorrhoea should be having run the risk, and not the presence of symptoms. Routine tests of the anorectum for gonorrhoea are essential in cases of 80 women at risk, and for most homosexual men since over 80 per cent of these men will have had passive anorectal intercourse. Because gonococcal infections following treatment-failure are often clinically silent in both women and men, symptoms cannot be relied upon to indicate such failure. Follow-up smears and cultures are always essential.     

Risk factors for urethritis in heterosexual men. The role of fellatio and other sexual practices

BACKGROUND: Nonchlamydial nongonococcal urethritis (NGU) is a common sexually transmitted disease (STD) in heterosexual men. Prior studies have suggested that NGU may be acquired by insertive oral sex. GOAL: To assess the association of oral sex and other sexual practices with nonchlamydial NGU in heterosexual men in order to better understand this syndrome and to guide its prevention and treatment. Risk factors for urethral gonorrhea and chlamydial infection were explored to contrast with NGU. STUDY DESIGN: A retrospective case-control study was conducted among heterosexual men attending as STD clinic during 1993 and 1994. The study included 4,848 men who were sexually active within the prior 2 months and had urethral specimens obtained for Gram's stain, culture for Neisseria gonorrhoeae, and culture for Chlamydia trachomatis. RESULTS: Insertive oral sex was not shown to be an independent risk factor for NGU. Independent predictors of nonchlamydial NGU by multivariate analysis included African-American race (odds ratio [OR] 3.71, 95% confidence interval [95% CI] 3.06 to 4.50) and having > or = two sex partners in the prior 2 months (OR 1.45, 95% CI 1.20 to 1.75). History of using condoms "always" was negatively associated with NGU (OR 0.59, 95% CI 0.43 to 0.79), gonorrhea (OR 0.31, 95% CI 0.17 to 0.56), and chlamydial infection (OR 0.67, 95% CI 0.44 to 1.03). CONCLUSIONS: This study supports the sexually transmitted nature of nonchlamydial NGU but did not confirm an association with oral sex. However, the analysis was compromised by the rarity of insertive oral sex as patients' only sexual exposure. Consistent condom use protects against all causes of sexually acquired urethritis.     

Trial production of an admittance plethysmograph]

Direct urethral and cervical smears for gonorrhea in women are useful because of their high specificity. Male rectal smears are less efficacious. Direct tests for candidiasis and trichomoniasis are also specific, but less sensitive than generally thought. Most tests exhibit only moderate month-to-month variability. No association between infection with trichomonads and gonococci was demonstrated. The gonococcal tests all perform best under conditions of high prevalence, such as those that obtain in venereal disease clinics in the United States.     

Human immunodeficiency virus infection of the human thymus and disruption of the thymic microenvironment in the SCID-hu mouse

Infection with the human immunodeficiency virus (HIV) results in immunosuppression and depletion of circulating CD4+ T cells. Since the thymus is the primary organ in which T cells mature it is of interest to examine the effects of HIV infection in this tissue. HIV infection has been demonstrated in the thymuses of infected individuals and thymocytes have been previously demonstrated to be susceptible to HIV infection both in vivo, using the SCID-hu mouse, and in vitro. The present study sought to determine which subsets of thymocytes were infected in the SCID-hu mouse model and to evaluate HIV-related alterations in the thymic microenvironment. Using two different primary HIV isolates, infection was found in CD4+/CD8+ double positive thymocytes as well as in both the CD4+ and CD8+ single positive subsets of thymocytes. The kinetics of infection and resulting viral burden differed among the three thymocyte subsets and depended on which HIV isolate was used for infection. Thymic epithelial (TE) cells were also shown to endocytose virus and to often contain copious amounts of viral RNA in the cytoplasm by in situ hybridization, although productive infection of these cells could not be definitively shown. Furthermore, degenerating TE cells were observed even without detection of HIV in the degenerating cells. Two striking morphologic patterns of infection were seen, involving either predominantly thymocyte infection and depletion, or TE cell involvement with detectable cytoplasmic viral RNA and/or TE cell toxicity. Thus, a variety of cells in the human thymus is susceptible to HIV infection, and infection with HIV results in a marked disruption of the thymic microenvironment leading to depletion of thymocytes and degeneration of TE cells.     

Loss of Helicobacter pylori hemagglutination with serial laboratory passage and correlation of hemagglutination with gastric epithelial cell adherence

Adherence of Helicobacter pylori to gastric epithelial cells is thought to be important in the pathogenesis of infection and may be essential to maintain lifelong colonization. However, the factors responsible for adherence to gastric epithelial cells in vivo have not been characterized, and the significance of adherence to standard epithelial cell lines is unclear. Hemagglutination is also thought to be important in H. pylori adherence. However, no studies have clearly linked H. pylori hemagglutination or adherence to cultured epithelial cells to primary gastric epithelial cell adherence. Furthermore, it is not clear whether laboratory strains which have undergone multiple passages lose potential colonization factors. In this study, we examined the effect of serial laboratory passage on hemagglutination and correlated the hemagglutination characteristics of H. pylori strains to primary gastric cell adherence. Variable expression of hemagglutination was seen with serial laboratory passage of 15 strains. After 100 serial laboratory passages, all strains had lost hemagglutination activity. Hemagglutination was seen in association with adherence to primary gastric cells in vitro isolated from 2 patients. An association with ultrastructural intimate adherence was seen with HEp-2 cells, but not with gastric adenocarcinoma cells. Ultrastructural adherence was seen in corresponding antral biopsies of patients whose strains were hemagglutination positive, but hemagglutination was not associated with gastric inflammation. These data indicate that H. pylori hemagglutination is lost with serial passage and that hemagglutination may play a role in the attachment of H. pylori to gastric epithelial cells, but the role of adherence to chronic gastric inflammation is unclear.     

Collaborative study of a semiautomated method for the analysis of prednisolone and prednisone tablets

A simple, adequately evaluated serologic test is not now available for use in gonorrhea screening programs. Some of the factors responsible for the relatively low sensitivity and specificity of serologic tests for gonorrhea as compared to cultural techniques are discussed. These include the time required for development of an immunologic response after infection, cross-reactivity with other antigens, and the persistence of antibody after therapy. At present, gonococcal serologic tests may be useful to the clinician in establishing the diagnosis of disseminated gonococcal infection, especially if paired sera demonstrate a change in antibody titer. Current research on the antigenic structure of the gonococcus may lead to the development of improved serologic tests for use in screening programs. However, the performance of any test may vary according to sex of the patient, presence of symptoms, history of prior gonococcal infection, and duration of the current infection. The physician must understand these factors when considering the use of any serologic test for gonorrhea.     

Transrectal ultrasound in male urethritis

OBJECTIVE: To assess the prevalence of prostatic abnormalities in men with gonococcal and non-gonococcal urethritis using trans-rectal ultrasonic markers. DESIGN: A case control study of patients attending a department of genitourinary medicine with symptoms of urethritis. SETTING: Department of Genitourinary Medicine and Department of Radiology in Manchester Royal Infirmary. RESULTS: A total of 42 patients were recruited to the study: 26 with urethritis and 16 controls. Of the 26 study patients, six were gonococcal, four chlamydial, two mixed gonococcal and chlamydia and nine non specific (no organisms detected). Of the 26 study patients, 16 had abnormal scans (61.5%), eight from the chlamydia group and eight from the non specific group. No abnormalities were found in the gonococcal and mixed group. Of the 16 control patients, five had abnormal scans (31.25%), three of these have had a past history of chlamydial urethritis. CONCLUSION: The prevalence of prostatic abnormalities in patients with non-gonococcal urethritis was significantly higher when compared with controls. The cause of these abnormalities is unclear, but is compatible with inflammatory changes within the gland.     

Vectorial release of poliovirus from polarized human intestinal epithelial cells

Polarized epithelial cells represent the primary barrier to virus infection of the host, which must also be traversed prior to virus dissemination from the infected organism. Although there is considerable information available concerning the release of enveloped viruses from such cells, relatively little is known about the processes involved in the dissemination of nonenveloped viruses. We have used two polarized epithelial cell lines, Vero C1008 (African green monkey kidney epithelial cells) and Caco-2 (human intestinal epithelial cells), infected with poliovirus and investigated the process of virus release. Release of poliovirus was observed to occur almost exclusively from the apical cell surface in Caco-2 cells, whereas infected Vero C1008 cells exhibited nondirectional release. Structures consistent with the vectorial transport of virus contained within vesicles or viral aggregates were observed by electron microscopy. Treatment with monensin or ammonium chloride partially inhibited virus release from Caco-2 cells. No significant cell lysis was observed at the times postinfection when extracellular virus was initially detected, and transepithelial resistance and vital dye uptake measurements showed only a moderate decrease. Brefeldin A was found to significantly and specifically inhibit poliovirus biosynthetic processes by an as yet uncharacterized mechanism. The vectorial release of poliovirus from the apical (or luminal) surface of human intestinal epithelial cells has significant implications for viral pathogenesis in the human gut.     

Ligase chain reaction for detection of Neisseria gonorrhoeae in urogenital swabs

The ligase chain reaction (LCR) is an in vitro nucleic acid amplification technique that exponentially amplifies targeted DNA sequences. In a multicenter study, we evaluated the use of a 4-h LCR-based assay for the diagnosis of Neisseria gonorrhoeae infection of the cervix and male urethra. The LCR results were compared with those of culture for N. gonorrhoeae by using selective media. This assay amplifies target sequences within the N. gonorrhoeae opacity gene. Discordant LCR-positive and culture-negative specimens were further evaluated by testing by another LCR assay which used N. gonorrhoeae-specific pilin probe sets. A total of 1,539 female endocervical specimens and 808 male urethral swab specimens were evaluated in the study. An expanded "gold standard" was defined to include all culture-positive as well as culture-negative, confirmed LCR-positive specimens. After resolution of discrepant samples, the sensitivities of the N. gonorrhoeae LCR assays for the female and male specimens were 97.3 and 98.5%, respectively, with specificities of 99.6 and 99.8%, respectively. Resolved culture sensitivities were 83.9 and 96.5% for the female and male specimens, respectively. The LCR assay for gonorrhea is a rapid, highly sensitive nonculture method for detecting gonococcal infection of the cervix and male urethra.     

Interpretive algorithms for the symptom-limited exercise test: assessing dyspnea in Persian Gulf war veterans

The mechanisms by which respiratory syncytial virus (RSV) infection induces bronchiolitis and airway disease are unclear. The presence of large numbers of polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection suggests a potential role of PMN in airway injury associated with RSV infection. To investigate the potential role of neutrophils in RSV bronchiolitis, human alveolar type II cells (A549 cells) were infected with different doses of RSV for 6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image analysis was used to determine PMN adhesion and detachment of epithelial cells. The results showed that RSV infection of epithelial cells enhanced PMN adherence in a dose- and time-dependent pattern, RSV infection alone could damage and detach epithelial cells to a limited extent and PMN significantly augmented RSV infection-induced damage and detachment of epithelial cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances neutrophil adhesion to the epithelium and that activated neutrophils augment the damage and detachment of epithelium infected with the virus. Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory syncytial virus airway disease by inducing epithelial damage and cell loss.     

The individual at high risk for endometrial carcinoma

The relative frequency of gonorrhea and nongonococcal urethritis was studied among all active duty US Navy and Marine Corps personnel. Between 1966 and 1974, the incidence of the two diseases increased in parallel fashion, reaching 80.2 cases of gonorrhea and 61.8 cases of nongonococcal urethritis per 1000 average strength in 1974. The 56,457 cases of gonorrhea and 43,538 cases of nongonococcal urethritis reported in 1974 were unevenly distributed geographically. In the United States that year, nongonococcal urethritis was the more commonly reported condition, with 32.9 cases per 1000 average strength per year compared to 28.6 for gonorrhea; and, for the last four years, the ratio of the two was 1.05 cases of nongonococcal urethritis for each case of gonorrhea. These findings imply that nongonococcal urethritis is a significantly greater problem than has been generally recognized.     

A monoclonal antibody pool for routine immunohistochemical detection of human respiratory syncytial virus antigens in formalin-fixed, paraffin-embedded tissue

Four monoclonal antibodies (MAbs) with specificities for epitopes on human respiratory syncytial virus (RSV) proteins preserved after formalin fixation and paraffin embedding were identified in fixed and embedded virus-infected HEp-2 cell pellets. The MAbs bound epitopes on the fusion protein, the nucleoprotein, the phosphoprotein, and the M2 protein of the virus. Following high-temperature antigen unmasking, immunohistochemical staining revealed RSV antigens in the lungs of five of seven children who died with confirmed RSV infection and in none of nine children who died for other reasons, with no evidence of RSV infection. Staining was cytoplasmic, granular, and confined to epithelial cells. Intense staining was seen at the apex of ciliated bronchial and bronchiolar epithelial cells in all five positive cases. In one case, of pneumonitis, infected pneumocytes were present in the alveoli and in several cases, CD68-positive, cytokeratin-negative alveolar macrophages stained for viral antigens. These antibodies may prove useful in studies of the pathogenesis of RSV infection.     

Allopurinol hypersensitivity syndrome: hypersensitivity to oxypurinol but not allopurinol

OBJECTIVE: We assessed the clinical, histological, and virological features of anogenital human papillomavirus (HPV) infection, according to their immune status in HIV-1 infected men, referred for an anogenital examination or treatment, in comparison with immunocompetent patients. METHODS: The study population comprised 33 HIV-1 infected heterosexual or homosexual men and 38 HIV negative men seen in a screening and treatment centre for anogenital HPV infections. All patients were examined with a colposcope. Biopsies were carried out on all subjects with anogenital lesions for histological studies and HPV detection by Southern blot. RESULTS: The HIV infected patients had a balanopreputial HPV infection in 70%, anal in 30%, and urethral in 37%, while HIV negative patients had balanopreputial lesion in 72%, anal in 26%, and urethral in 16%. Diffuse anogenital lesions were present in 33% of the HIV infected cases and in 10.5% of HIV negative cases (p < 0.02). Among the HIV infected patients, the genital HPV lesions were condylomatous in 67.5% of the cases and dysplastic in 57%. HIV negative patients had condylomatous lesions in 86% of the cases and dysplasic in 14%. The condylomatous lesions of HIV infected patients had a low grade malignant histological aspect in 36% of the cases and high grade histological criteria were found in 22% of the dysplasias. Oncogenic HPVs were detected more frequently in HIV infected patients (35% v 12%) and more than one HPV type was found in 21.5% of cases. Neither the anogenital diffusion of the HPV lesions nor their morphological, histological, and virological features differed significantly in patient with CD4 cell counts > or < 200 x 10(6)/l. In contrast, patients with CD4 cell counts < 50 x 10(6)/l had a higher risk of several types of HPVs and of developing a diffuse anogenital infection. CONCLUSION: HIV-1 infected patients had an increased frequency of high grade anogenital dysplastic lesions and a higher frequency of HPV infection with multiple and diffuse sites of involvement. These characteristics of HPV infection were independent of the patients' immune status up to CD4 cell counts > 50 x 10(6)/l but showed an increased risk when the CD4 cell count was < 50 x 10(6)/l. The higher frequency of diffuse anogenital infections among HIV infected men calls for rapid treatment, laser or surgery, given the association of histological features of intraepithelial neoplasia and the presence of multiple HPV infection sites which may be the consequence of immune disturbances, most of which are transmissible potentially oncogenic HPVs.     

Human immunodeficiency virus infection abolishes CD4-dependent activation of ZAP-70 by inhibition of p56lck

The effect of early human immunodeficiency virus-1 infection in vitro on proximal signal transduction events in primary peripheral blood lymphocytes was investigated with respect to CD4-mediated costimulation of CD3/T cell-receptor signalling. Tyrosine phosphorylation profiles induced by CD4 and CD3 + CD4 ligation were profoundly abrogated in virally infected cells, although CD4 receptor expression remained intact during early infection. Furthermore, the association of the tyrosine kinase p56lck with the CD4 receptor was reduced in virally infected cells. The downmodulation of CD4-mediated CD3 signalling coincided with the subsequent inhibition of the activity and tyrosine phosphorylation of the downstream kinase ZAP-70 in virally infected cells. The observed virally mediated cosignalling defects during early infection may account for the inhibition of distal signal events and thus contribute to HIV pathogenesis, such as reduced immune response to antigenic exposure, anergy, and apoptosis.     

Calcium and endoplasmic reticulum dynamics during oocyte maturation and fertilization in the marine worm Cerebratulus lacteus

Disseminated gonococcal infection is the most common systemic complication of acute gonorrhea and occurs in 0.5% to 3.0% of patients with untreated mucosal infection. It is also the most common cause of septic arthritis in patients less than 30 years of age. Fortunately, the incidence of gonorrhea is decreasing dramatically in the United States and Western Europe, although it is still high in developing countries. Increasing resistance to antibiotics requires continuous surveillance of antimicrobial susceptibilities to determine the efficacy of current therapeutic measures.     

Apoptosis of human intestinal epithelial cells after bacterial invasion

Epithelial cells that line the human intestinal mucosa are the initial site of host invasion by bacterial pathogens. The studies herein define apoptosis as a new category of intestinal epithelial cell response to bacterial infection. Human colon epithelial cells are shown to undergo apoptosis following infection with invasive enteric pathogens, such as Salmonella or enteroinvasive Escherichia coli. In contrast to the rapid onset of apoptosis seen after bacterial infection of mouse monocyte-macrophage cell lines, the commitment of human intestinal epithelial cell lines to undergo apoptosis is delayed for at least 6 h after bacterial infection, requires bacterial entry and replication, and the ensuing phenotypic expression of apoptosis is delayed for 12-18 h after bacterial entry. TNF-alpha and nitric oxide, which are produced as components of the intestinal epithelial cell proinflammatory program in the early period after bacterial invasion, play an important role in the later induction and regulation of the epithelial cell apoptotic program. Apoptosis in response to bacterial infection may function to delete infected and damaged epithelial cells and restore epithelial cell growth regulation and epithelial integrity that are altered during the course of enteric infection. The delay in onset of epithelial cell apoptosis after bacterial infection may be important both to the host and the invading pathogen since it provides sufficient time for epithelial cells to generate signals important for the activation of mucosal inflammation and concurrently allows invading bacteria time to adapt to the intracellular environment before invading deeper mucosal layers.