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A Eley

Publications and source records attributed to A Eley.

At least 19 recordsLinked to original sources
PubMed2005

Apoptosis of ejaculated human sperm is induced by co-incubation with Chlamydia trachomatis lipopolysaccharide.

BACKGROUND: Previous work has shown that co-incubation of human sperm with Chlamydia trachomatis serovars E and LGV leads to premature sperm death and that this is due primarily to chlamydial lipopolysaccharide (LPS). Here, we investigated the possible involvement of apoptosis in this premature sperm death. METHODS: Highly motile preparations of sperm from normozoospermic patients were co-incubated for 6 h with extracted LPS from C. trachomatis serovars E and LGV. Three different methods were used to determine if LPS-treated sperm underwent apoptosis, including: (i) flow cytometry; (ii) measurement of ADP:ATP ratios; and (iii) measurement of mono- and oligonucleosomal DNA fragments. Caspase activity was also investigated by fluorimetry and by use of a pan-caspase inhibitor and caspase-3 inhibitor. RESULTS: All three methods used for detection indicated that C. trachomatis LPS induced some apoptosis in sperm after 6 h when compared with a staurosporine (apoptosis-positive) control. Moreover, a greater degree of apoptosis was seen with C. trachomatis serovar E than with serovar LGV. It was also shown that C. trachomatis LPS-induced apoptosis of sperm could be blocked with a pan-caspase inhibitor and a caspase-3 inhibitor. Moreover, by using a fluorogenic substrate, apoptosis was shown to be caspase-mediated. CONCLUSIONS: In general it is believed that apoptosis does not occur in C. trachomatis-infected host cells. However, using three different methods, our findings clearly indicate that co-incubation of sperm with C. trachomatis LPS results in cellular death which is in part due to apoptosis and is caspase-mediated. These findings provide an explanation as to how C. trachomatis can mediate premature death in human sperm.

Amino Acid Chloromethyl Ketones↗
PubMed2004

Chlamydia trachomatis and male fertility.

There is increasing evidence that the function of human spermatozoa can be significantly affected by direct exposure to the bacterium Chlamydia trachomatis. This may contribute to sub-fertility in infected individuals by a route that is independent of any damage to the reproductive epithelium. In addition, if a C. trachomatis infection is undiagnosed it could contribute to poor outcomes in assisted conception techniques such as in vitro fertilization. The antibiotics routinely used in IVF culture systems are largely ineffective against chlamydia, emphasizing the importance of screening patients prior to treatment. Moreover, given the many thousands of semen samples provided for analysis by men in primary care (many of which will never undergo assisted conception treatment), it is suggested that this may represent a wasted opportunity to provide screening (and treatment) for the infection using an appropriate test specimen and without the need for additional hospital visits.

Anti-Bacterial Agents↗
PubMed2003

Chlamydia trachomatis-induced death of human spermatozoa is caused primarily by lipopolysaccharide.

Elementary bodies (EBs) of Chlamydia trachomatis serovar E are more toxic to sperm than those from serovar LGV. In this study, lipopolysaccharide (LPS) was prepared from the EBs of both serovars and incubated with human spermatozoa at concentrations that matched the LPS concentration of EBs. The effects of EBs and LPS on sperm motility, viability and acrosomal status were then determined. Sperm motility was measured by computer-assisted sperm analysis and the hypo-osmotic swelling test was used to determine the proportion of dead cells. Acrosomal status was examined using a standard mAb assay. Over a 6 h incubation, LPS from both serovars resulted in a marked reduction in sperm motility (and a concomitant increase in the proportion of dead spermatozoa) in a manner similar to that seen in response to EBs of serovar E. In addition, when sperm were incubated with a range of doses of EBs and LPS, probit analysis revealed that the greater spermicidal effects of EBs from serovar E (when compared with serovar LGV) were not observed when sperm were incubated with LPS from the two serovars. This suggests that the more potent effect of EBs of serovar E cannot be explained entirely by differences in the composition of LPS. Interestingly, Escherichia coli LPS was required in doses 500 times more concentrated than chlamydial LPS in order to kill a similar proportion of sperm, suggesting that bacterial LPSs may differ in their spermicidal properties. However, that chlamydial LPS was spermicidal was demonstrated by the use of polymyxin B (a polycationic antibiotic known to neutralize LPS effects), confirming that the effects observed were primarily a result of LPS activity.

Cell Death↗
PubMed2001

Co-incubation of human spermatozoa with Chlamydia trachomatis serovar E causes premature sperm death.

The aim of this work was to investigate the effect of elementary bodies (EB) of Chlamydia trachomatis serovars E and LGV on sperm motility, viability and acrosomal status. Highly motile preparations of spermatozoa from normozoospermic patients were co-incubated for 6 h with 0.54x10(6) EB per ml. At 1, 3 and 6 h of incubation, sperm motility was determined by computer-assisted semen analysis (CASA) and the proportion of dead cells determined by the hypo-osmotic swelling (HOS) test. Acrosomal status was also examined using a standard monoclonal antibody assay. In the absence of EB, the percentage of motile spermatozoa remained >69% over the 6h incubation and the proportion of dead spermatozoa at <12%. However, during the incubation with EB of serovar E there was a significant decline in the percentage of motile spermatozoa (P < 0.05), and a corresponding increase in the proportion of dead spermatozoa (P < 0.05) at all time-points. However, following incubation with serovar LGV, only the percentage of dead spermatozoa after 6 h incubation was significantly different from the control (P < 0.05). The amount of acrosome-reacted spermatozoa remained unchanged (<16%) in all incubations at all time-points. Dose-response experiments indicated that increasing the concentration of EB to 2.5x10(6) per ml did not significantly alter the results. Furthermore, co-incubation of spermatozoa with dead EB (killed by heat treatment) abolished the chlamydia-mediated response, indicating that the effect is a result of the live organism and not soluble components or membrane elements. These data suggest that a detrimental effect on sperm function by some serovars may be an as yet unrecognized component of infertility problems.

Acrosome Reaction↗
PubMed2001

Infectivity of Chlamydia trachomatis serovar LGV but not E is dependent on host cell heparan sulfate.

The ability of heparan sulfate, heparin, and other glycosaminoglycans to inhibit the infectivity of Chlamydia trachomatis serovars E and LGV was examined using a simple competitive inhibition assay with three cell types from the human female reproductive tract, including primary human endosalpingeal cells. With the majority of the glycosaminoglycans tested, LGV was more significantly inhibited than serovar E. We have compared chlamydial infectivity between a wild-type Chinese hamster ovary cell line and two glycosaminoglycan-deficient cell lines. LGV was shown to be unable to infect heparan sulfate-deficient and GAG-deficient Chinese hamster ovary cell lines, whereas the E serovar infected these cells as efficiently as the control (nondeficient) cells. These two sets of experiments confirmed that serovar LGV is more dependent on a heparan sulfate-related mechanism of infectivity than is serovar E. This is further supported by the fact that attempts to purify a heparan sulfate-like molecule from either serovar cultured in glycosaminoglycan-deficient cell lines were nonproductive. Previous reports have suggested that chlamydia are able to produce a heparan sulfate-like molecule that is important for attachment and infectivity. We have attempted to detect possible binding of a specific heparan sulfate antibody to C. trachomatis by flow cytometry. Results showed no binding of the heparan sulfate antibody to C. trachomatis serovar LGV or E. Our results strongly indicate that chlamydiae do not produce a heparan sulfate-like molecule but rather use host cell heparan sulfate in order to infect cells.

Animals↗
PubMed2000

Inhibition of chemotaxis by organic acids from anaerobes may prevent a purulent response in bacterial vaginosis.

It has been postulated that certain organic acids produced by the anaerobes associated with bacterial vaginosis (BV) could prevent a purulent response in this infection. Varying concentrations of pure succinic, acetic and lactic acids were incubated in vitro with a monocytic cell line (MonoMac 6). High inhibition of chemotaxis was produced by succinic acid; lower inhibition and no inhibition was shown by acetic acid and lactic acid respectively. Succinic and acetic acids were detected in high concentrations in the vaginal fluid of women with BV and in culture supernates of Prevotella and Mobiluncus spp.; these acids impaired chemotaxis of MonoMac 6 cells in vitro. The vaginal fluids of normal women and the culture supernates of Lactobacillus spp. had no effect on chemotaxis.

Bacteria, Anaerobic↗
PubMed2000

Coincubation of human spermatozoa with Chlamydia trachomatis in vitro causes increased tyrosine phosphorylation of sperm proteins.

Elementary bodies (EBs) of the obligate intracellular bacterium Chlamydia trachomatis are responsible for the first step of attachment to host cells. We have studied the effects of EBs on human sperm protein tyrosine phosphorylation, which is important to sperm function. Indirect immunofluorescence using antiphosphotyrosine antibodies showed that serovar E, but not LGV, caused increased tyrosine phosphorylation which was localized to the sperm tail region. Immunoblotting revealed that serovar E caused a marked increase in tyrosine phosphorylation of 80- and 95-kDa sperm proteins, whereas serovar LGV caused increased phosphorylation of only the 80-kDa moiety. Considering the importance of tyrosine phosphorylation for sperm capacitation and other aspects of sperm function, we conclude that EBs may affect these events.

Chlamydia trachomatis↗
PubMed1999

Is VZV reactivation a common cause of unexplained unilateral pain? Results of a prospective study of 57 patients.

OBJECTIVE: Pain is a common reason for patients to present to a doctor. Many patients with zoster have seen their doctor with pain during the days before the rash and zoster sine herpete is well described. If early varicella zoster virus (VZV) reactivation could be identified confidently, it could provide an opportunity for early antiviral intervention. This prospective study was performed to assess how often patients presenting to their general practitioner with unilateral pain of no obvious clinical cause proved to have evidence of VZV reactivation. METHODS: Fifty-seven patients were recruited and followed for 28 days; laboratory testing included VZV polymerase chain reaction (PCR) from peripheral blood mononuclear cells, VZV IgG, IgA and IgM. The control group consisted of 81 blood donors. RESULTS: Only two study patients developed the rash of zoster. There was no significant difference in PCR or serological responses between the study group and control group. Clinical characteristics did not enable identification of patients presenting to their doctor with unilateral pain who had prodromal zoster. CONCLUSION: There was no evidence on clinical or laboratory tests used in this study to support the view that reactivation of VZV is a common cause of unexplained unilateral pain.

Adult↗
PubMed1999

Antimicrobial susceptibility testing of Chlamydia trachomatis using a reverse transcriptase PCR-based method.

The conventional method for antimicrobial susceptibility testing of Chlamydia trachomatis is subjective and potentially misleading. We have developed a reverse transcriptase PCR (RT-PCR)-based method which is more sensitive and less subjective than the conventional method. Using 16 strains of C. trachomatis in triplicate assays, we found the RT-PCR method consistently more sensitive than the conventional technique for all eight antimicrobials tested, with resultant MICs determined by RT-PCR ranging from 1.6-fold higher (erythromycin) to >/=195-fold higher (amoxicillin).

Amoxicillin↗
PubMed1998

The relation between immunoglobulin G antibodies to Chlamydia trachomatis and poor ovarian response to gonadotropin stimulation before in vitro fertilization.

OBJECTIVE: To determine whether a relation exists between previous exposure to Chlamydia trachomatis and impaired ovarian response to gonadotropin stimulation. DESIGN: Controlled clinical study. SETTING: Two university IVF centers. PATIENT(S): Two hundred forty-two patients receiving IVF treatment and 81 control patients. Ninety-four patients with a poor response to IVF, defined by cycle cancellation in response to a daily stimulation dose of 300 IU of FSH, and 148 patients with a good response were matched for age. Twenty-eight pregnant controls and 53 controls of proven fertility also were included. INTERVENTION(S): Serum samples were obtained from patients and controls. Serum levels of immunoglobulin (Ig) G antibodies to C. trachomatis were determined by ELISA. MAIN OUTCOME MEASURE(S): The prevalence of serum IgG antibodies to C. trachomatis in critically defined poor responders was compared with that of age-matched good responders. RESULT(S): A significantly higher proportion of poor responders had serum IgG antibodies to C. trachomatis compared with good responders (44.7% and 30.4%, respectively). Patients undergoing IVF had a significantly higher prevalence of IgG antibodies to C. trachomatis (36%) than did either pregnant or nonpregnant controls (12%). CONCLUSION(S): A significantly higher prevalence of serum IgG antibodies to C. trachomatis was observed in critically defined poor responders, suggesting a possible detrimental effect of C. trachomatis on subsequent ovarian function.

Adult↗
PubMed1998

Phospholipids of Fusobacterium spp.

The aim of this study was to analyse individual polar lipid analogues, within each lipid family present, of fusobacteria using fast atom bombardment mass spectrometry (FAB-MS). Polar lipid extracts were prepared, washed and dried. Samples, dispersed in a matrix of m-nitrobenzyl alcohol, were analysed by negative ion FAB-MS using xenon as the reagent gas. Major anion peaks observed in the low mass region of mass/charge (m/z), 211, 221, 225, 227, 239, 241, 249, 251, 253, 255, 273, 277, 279, 281, 289 and 291, were consistent with the presence of C13:1, C14:3, C14:1, C14:0, C15:1, C15:0, C16:3, C16:2, C16:1, C16:0, unknown, C18:3, C18:2, C18:1, unknown and C19:3 carboxylate anions. In the high mass region, major anion peaks observed with m/z 644, 646, 648, 660, 662, 672, 673, 674, 686, 688, 689, 690, 698, 700, 701, 703, 714, 716, 717 and 719 were consistent with the presence of phosphatidylethanolamine (PE) (29:2), PE (29:1), PE (29:0), PE (30:1), PE (30:0), PE (31:2), first isotope of PE (31:2), PE (31:1), PE (32:2), PE (32:1), first isotope peak of PE (32:1), PE (30:0), PE (33:3), PE (33:2), phosphatidylglycerol (PG) (31:3), PG (31:2), PE (34:2), PE (34:1), PG (32:2) and PG (32:1). We conclude that FAB-MS can provide data on individual analogues of PE and PG from Fusobacterium spp. not readily obtained by other means. Furthermore, the phospholipid profile is diagnostic for the genus.

Fusobacterium↗
PubMed1997

Molecular evolution of the tet(M) gene in Gardnerella vaginalis.

Five clinical isolates of Gardnerella vaginalis known to carry the tetracycline resistance determinant Tet M were examined by hybridization and nucleotide sequencing. Four of the strains carried tet(M) genes with identical sequences. The two versions of the tet(M) gene found in G. vaginalis did not show complete identity with other published tet(M) sequences, but showed mosaic structures with regions of homology to tet(M) gene sequences from Tn916, Tn1545 and the American type plasmid found in Neisseria gonorrhoeae. Hybridization studies showed that all isolates carried the tet(M) gene on a single HindII restriction fragment of variable length. No evidence was found for the presence of sequences homologous to the transposition functions of Tn916.

Base Sequence↗
PubMed1997

Lymphogranuloma venereum: biopsy, serology, and molecular biology.

A 21 year old woman presented with painful groin lymphadenopathy and malaise. Lymph node biopsy, to exclude atypical infection and malignancy, suggested the diagnosis of lymphogranuloma venereum. This diagnosis was confirmed by serology and polymerase chain reaction, with the patient subsequently admitting to a casual sexual contact within the United Kingdom. Alternative methods of investigation of this disease are discussed.

Adult↗
PubMed1996

Adherence of Aeromonas caviae to human cell lines Hep-2 and Caco-2.

Adherence of Aeromonas caviae to HEp-2 and Caco-2 cell monolayers was investigated with 24 clinical isolates. Growth phase, temperature, multiplicity of infection and length of incubation affected adherence. Treatment of the bacteria with trypsin, sodium metaperiodate, mechanical shearing and the addition of cytochalasin B and cycloheximide to the monolayer significantly reduced the adherence capabilities of the strains investigated. The use of chloramphenicol to inhibit protein synthesis reduced the adhesive capabilities of bacteria grown in liquid medium and those subjected to mechanical shearing. Light microscopy, scanning and transmission electron microscopy were employed in the investigation of bacteria-bacteria and bacteria-monolayer interactions and indicated similarities with the aggregative adherence patterns of the Enterobacteriaceae. The presence of extracellular bacterial appendages and their correlation with increased adhesive capacity may indicate a role in the process of adherence.

Aeromonas↗