Environmental drivers of increased ecosystem respiration in a warming tundra.

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

Overcoming existential loneliness: a cross-cultural study.

BACKGROUND: Moving into a long-term care facility (LTCF) can reduce the ability for older adults to engage in meaningful roles and activities and the size of their social network. These changes and losses can lead them to experience existential loneliness (EL)-the intolerable emptiness and lack of meaningful existence resulted from the losses they have experienced. While EL has often been understood as a universal human experience, it has primarily been studied in people from Western cultures; little is known about how EL may be experienced by and manifested in people from Eastern cultures. Hence, this qualitative study aimed to describe the experience and coping of EL in Hong Kong Chinese and Swedish older adults living in LTCFs. METHODS: A qualitative study using Thorne's (2004) interpretive description was conducted. Thirteen Chinese and 9 Swedes living in LTCFs in Hong Kong, China and Malmo, Sweden, respectively were interviewed about their experience of EL in two series of semi-structured interviews. Data were analyzed using thematic analysis. RESULTS: The core theme of "overcoming EL" described the participants' experience of EL, which came about through the combined process of "Feeling EL" and "Self-Regulating". Both Chinese and Swedish participants had similar experience with EL. Realizing that they did not want to living with EL anymore, they coped by reframing their experience and identifying new meaning in their life. CONCLUSIONS: The study findings suggested that early and clear counselling support that help older adults to define new meaning in life may help them cope. In addition, more opportunities should be available at the LTCFs to promote quality relationships, enable older adults to reflect on their lives with pride, and support their ability to do the things they enjoy.

Peripherally inserted central catheter in extremely preterm infants: Characteristics and influencing factors.

OBJECTIVE: To evaluate the duration of catheter stay, incidence of non-elective removal and rates of complications associated with peripherally inserted central catheters (PICCs) in relation to different catheter positions in extremely preterm infants (EPT, <28 weeks of gestation). METHODS: A retrospective analysis of Peripherally Inserted Central Catheters (PICCs) inserted in EPT infants over a 10-year period, from January 2004 through December 2013 (mean gestational age, 25.2 weeks; mean birth weight, 727 g). RESULTS: Of the 379 PICCs analyzed, the majority of lines (68%) were placed in the central position, and 259 PICCs (56%) were removed electively after fulfilment of the treatment. Significantly more PICCs in the lower extremities compared to the upper extremities were in central positions (86% vs 61%, p < 0.001, respectively). Significantly more PICCs that were removed electively after fulfilment of the treatment were in a central position compared to a non-central position (p < 0.001). Of the 166 catheters that were removed because of complications, most (71%) of them had mechanical problems, and 13% had sepsis resulting in an incidence rate of 4.4/1000 catheter days. CONCLUSION: PICCs inserted in the lower extremity were more likely to have a centrally placed tip position compared to PICC lines inserted in the upper extremities.

Transgender men's experiences of fertility preservation: a qualitative study.

STUDY QUESTION: How do transgender men experience fertility preservation (FP) by cryopreservation of oocytes? SUMMARY ANSWER: The procedures required prior to oocyte cryopreservation, such as hormonal ovarian stimulation and transvaginal ultrasound (TVS), have a negative impact on gender dysphoria as they are closely linked to the men's female assigned sex at birth, which is incompatible with their current status. WHAT IS KNOWN ALREADY: Transgender persons often have high dissatisfaction with assigned sex-specific body features, such as the genital organs and androgen/oestrogen-responsive features. Thus, undergoing FP that requires genital-specific examinations, aimed at obtaining oocytes to cryopreserve, could be distressing. As no previous studies have investigated transgender men's experiences of FP involving cryopreservation of oocytes, little is known about their experience of the procedures. STUDY DESIGN, SIZE, DURATION: This is a prospective study among adult transgender men referred for FP between March 2014 and December 2015. Individual in-depth qualitative interviews were conducted shortly after FP treatment. The interviews lasted between 62 and 111 min (mean 81 min) and were digitally recorded and transcribed verbatim. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were recruited on their first visit to the assisted reproduction clinic for reproductive counseling. There were 15 men, scheduled for FP, who chose to participate in the study (age 19-35); none had given birth and eight had a partner. Data were analyzed by thematic content analysis. MAIN RESULTS AND THE ROLE OF CHANCE: The analysis resulted in three main categories: the journey to FP, reactions to the FP proceedings and strategies for coping. The referral for FP was an important part of the assessment and diagnosis and sometimes lined with frustrating waits and doubts. The reaction to the FP proceedings revealed that the genital examinations and the physical changes associated with discontinuation of testosterone or hormonal stimulation treatment triggered gender incongruence and dysphoria. However, for some, the negative expectations were not met. The participants used several coping strategies in order to manage the procedure, such as focusing on their reasons for undergoing FP, reaching out to friends and family for support and the cognitive approaches of not hating their body or using non-gendered names for their body parts. The results demonstrate the importance of contextual sensitivity during FP procedures. LIMITATIONS, REASONS FOR CAUTION: The authors have strived to be reflective about their pre-understanding of the phenomenon. The majority of the participants resided in large urban areas; it is possible that transgender men living in rural areas have different experiences. WIDER IMPLICATIONS OF THE FINDINGS: As the results are based on qualitative data from 15 transgender men, the results cannot readily be generalized to larger populations. However, the results are suggested to be applicable to other transgender men who want to undergo FP by cryopreservation of oocytes. The results show that transgender men's experience of FP places may elicit gender incongruence and gender dysphoria. However, health care personnel can alleviate distress by using a gender-neutral language and the preferred pronoun. Also, reassuringly, the men also have coping strategies of how to handle the situation. This knowledge is important to ensure adequate professional support for patients with gender dysphoria during FP. STUDY FUNDING/COMPETING INTERESTS: Swedish Society of Medicine, Stockholm County Council and Karolinska Institutet (to K.A.R.-W.). TRIAL REGISTRATION NUMBER: N/A.

Fabrication and evaluation of SixNy coatings for total joint replacements.

Wear particles from the bearing surfaces of joint implants are one of the main limiting factors for total implant longevity. Si(3)N(4) is a potential wear resistant alternative for total joint replacements. In this study, Si(x)N(y)-coatings were deposited on cobalt chromium-discs and Si-wafers by a physical vapour deposition process. The tribological properties, as well as surface appearance, chemical composition, phase composition, structure and hardness of these coatings were analysed. The coatings were found to be amorphous or nanocrystalline, with a hardness and coefficient of friction against Si(3)N(4) similar to that found for bulk Si(3)N(4). The low wear rate of the coatings indicates that they have a potential as bearing surfaces of joint replacements. The adhesion to the substrates remains to be improved.

Sinonasal involvement in sarcoidosis: a report of seven cases and review of literature.

Sarcoidosis is a chronic systemic disease of unknown etiology characterized by non-caseating inflammation involving one or more organs with predilection for pulmonary and upper respiratory tract involvement. It presents with a variety of signs and symptoms which can be generalized or focused on a single organ. Sinonasal involvement is reported in about 1% of cases of sarcoidosis. Sarcoidosis can involve both the mucosa as well as bony structures in the nose and the paranasal sinuses. We present seven cases of sarcoidosis with sinonasal involvement. Four cases presented with nasal and sinus symptoms, and the other three cases developed or presented with nasal and sinus symptoms after the diagnosis of sarcoidosis was confirmed. The nasal and sinus symptoms in these patients were managed by local and systemic steroids. In four patients, endoscopic sinus surgery was performed with good outcome. Nasal and sinus symptoms, differential diagnosis and the treatment are discussed.

Health-related quality of life scores in long-term head and neck cancer survivors predict subsequent survival: a prospective cohort study.

OBJECTIVE: To examine the survival prediction of long-term health-related quality of life in patients with head and neck squamous cell carcinoma. DESIGN: Patients with head and neck squamous cell carcinoma diagnosed in the period between July 1992 and October 2001, who had been disease free for a minimum of 1 year following therapy, responded to structured interviews including several validated questionnaires in the period from October 2002 to March 2004. The study ended in June 2009 with a mean observation time of 75 ± 4 months among the survivors. Twenty-four deaths were observed. SETTING: University hospital, referral centre of the Western Norway. PARTICIPANTS: One hundred and thirty-nine cognitive functioning patients. MAIN OUTCOME MEASUREMENTS: Overall survival as of June 2009. This was correlated with various clinical factors and the EORTC QLQ-C30 questionnaire, the Eysenck Personality Inventory and the Coping inventory completed between October 2001 and March 2004. RESULTS: A general symptom sum score was significantly predictive of survival directly and after sequential adjustment for self-reported levels of neuroticism, avoidance focused coping, coping by suppression of competing activity, alcohol consumption, smoking status and heart/lung disease, as well as gender, age, time between diagnosis and inclusion, tumour node metastasis (TNM) stage and tumour site. Similar results were found for the health-related quality of life indices 'fatigue', 'dyspnoea' and 'sleep disturbance'. A dichotomised variable based on the general symptom sum score was calculated, and a high risk group, as to mortality, including less than a quintile of the total patient population was established. A hazard ratio of 5.15 was found for the dichotomised general symptom sum score. CONCLUSION: We have shown a unique and independent survival prediction from long-term EORTC QLQ-C30 scores in successfully treated and cognitive functioning head and neck squamous cell carcinoma patients.

MAPKs ERK and p38, but not JNK phosphorylation, modulate IL-6 and TNF-α secretion following OK-432 in vitro stimulation of purified human monocytes.

Interaction between the immune system and cancer allows for the use of biological response modifiers, e.g. OK-432, in cancer therapy. OK-432, penicillin-killed Streptococcus pyogenes, is used in treating carcinomas, but also lymphangiomas. We have studied the role of monocytes (MOs) in the immune response to OK-432 by examining IL-6 and tumour necrosis factor (TNF)-α secretion after in vitro MO stimulation with OK-432, to some extent in comparison with lipoteichoic acid (LTA) and lipopolysaccharide (LPS). LTA stimulation of whole blood gave IL-6 but not TNF-α secretion, as previously shown with OK-432 stimulation, whereas both cytokines were secreted following LPS stimulation. Addition of the MAPK kinase (MAPKK) MEK inhibitor U0126 inhibited IL-6/TNF-α secretion in a dose-dependent manner. Flow cytometry and to some extent Western blot (Wb) analyses showed that MAPK ERK, located downstream of MEK1/2, is predominantly phosphorylated at isolation from peripheral blood. Addition of the p38 MAP kinase inhibitor SB202190 decreased MO IL-6/TNF-α production upon OK-432 stimulation in a dose-dependent manner. Addition of the MAPK JNK inhibitor SP600125 did not systematically change the MO IL-6/TNF-α OK-432 response. Flow cytometry showed that when stimulating the MOs before isolation from blood, LPS yielded ERK phosphorylation and LPS/LTA p38 phosphorylation, whereas OK-432 had no effects on phosphorylation levels. In conclusion, we have shown that OK-432 resembles TLR2 more than TLR4 stimulation of MOs and depends on MAPKK MEK and MAPK p38, but not on JNK phosphorylation. The MEK and p38 MO OK-432 stimulation dependence is possibly related to the differentiation of cells of the MO lineage.

Spatial heterogeneity and plant species richness at different spatial scales under rabbit grazing.

Herbivores influence spatial heterogeneity in soil resources and vegetation in ecosystems. Despite increasing recognition that spatial heterogeneity can drive species richness at different spatial scales, few studies have quantified the effect of grazing on spatial heterogeneity and species richness simultaneously. Here we document both these variables in a rabbit-grazed grassland. We measured mean values and spatial patterns of grazing intensity, rabbit droppings, plant height, plant biomass, soil water content, ammonia and nitrate in sites grazed by rabbits and in matched, ungrazed exclosures in a grassland in southern England. Plant species richness was recorded at spatial scales ranging between 0.0001 and 150 m(2). Grazing reduced plant height and plant biomass but increased levels of ammonia and nitrate in the soil. Spatial statistics revealed that rabbit-grazed sites consisted of a mixture of heavily grazed patches with low vegetation and nutrient-rich soils (lawns) surrounded by patches of high vegetation with nutrient-poor soils (tussocks). The mean patch size (range) in the grazed controls was 2.1 +/- 0.3 m for vegetation height, 3.8 +/- 1.8 m for soil water content and 2.8 +/- 0.9 m for ammonia. This is in line with the patch sizes of grazing (2.4 +/- 0.5 m) and dropping deposition (3.7 +/- 0.6 m) by rabbits. In contrast, patchiness in the ungrazed exclosures had a larger patch size and was not present for all variables. Rabbit grazing increased plant species richness at all spatial scales. Species richness was negatively correlated with plant height, but positively correlated to the coefficient of variation of plant height at all plot sizes. Species richness in large plots (<25 m(2)) was also correlated to patch size. This study indicates that the abundance of strong competitors and the nutrient availability in the soil, as well as the heterogeneity and spatial pattern of these factors may influence species richness, but the importance of these factors can differ across spatial scales.

Co-culture of head and neck squamous cell carcinoma spheroids with autologous monocytes predicts prognosis.

Co-culture of monocytes with autologous fragment (F) spheroids originating from malignant (M) tumour or benign (B) control mucosa of head and neck squamous cell carcinoma (HNSCC) yields interleukin (IL)-6 and monocyte chemo-attractant protein (MCP)-1 secretion. This study investigates the association between this cytokine co-culture response and prognosis. Analysis of IL-6 and MCP-1 content of supernatants from monocytes in vitro co-culture with autologous MF- or BF-spheroids was investigated in a cohort of HNSCC patients (n = 65) diagnosed between 1998 and 2005, all of whom were treated with curative intent by primary surgery. The IL-6 response was expressed as a fraction of the lipopolysaccharid response of the same batch of monocytes. Recurrence, survival and causes of death were then established following the second part of 2005. MCP-1 levels did not predict prognosis. We found that increased levels of IL-6 from autologous monocytes in co-culture with MF-spheroids predicted recurrence with a hazard ratio (HR) of 1.5 [confidence interval (CI): 1.01-2.60; P = 0.05] and co-culture with BF-spheroids and monocytes predicted recurrence (HR = 4.17; CI: 1.54-11.29; P = 0.005). The same results where obtained in addition with TNM stage of the patients. Simultaneous analysis of BF- and MF-spheroid co-culture IL-6 responses as well as adjustment for age and TNM stage of the patients allowed prediction of total survival (HR = 3.1; CI: 1.11-8.56; P = 0.03) based on BF co-culture levels. IL-6 secreted upon in vitro co-culture with monocytes and BF-spheroids predicts recurrence and prognosis, whereas co-culture with monocytes and MF-spheroids predicts recurrence.

TNF-alpha is secreted by monocytes in transit to become macrophages, but not by peripheral blood monocytes, following OK-432 (lyophilized S. pyogenes) stimulation.

OK-432, penicillin-killed Streptococcus pyogenes, is used in treating lymphangiomas and carcinomas. We have studied proinflammatory interleukin (IL) secretion following OK-432 stimulation of total blood, peripheral blood mononuclear cell (PBMC) and purified monocytes in vitro. OK-432 stimulation of purified monocytes gave IL-1beta, IL-1RA, IL-6, IL-12p40 and tumour necrosis factor (TNF)-alpha response. OK-432 stimulation of cells within blood did, however, not yield TNF-alpha secretion. When PBMC or monocytes were cultured in low-attachment wells a decreased IL secretion was observed compared to adherent cells. Inhibition of Syk kinase with piceatannol, only at high, non-specific doses, but not PI3 kinase inhibition with LY294002 or Wortmannin, decreased monocyte IL response to OK-432. This shows that beta(1-3)-integrin receptor function is not necessary for monocyte OK-432-stimulated TNF-alpha secretion. Direct blockage of the beta(2)-integrin (CD18) receptor by anti-CD18 antibody was also unable to prevent the stimulating effects of OK-432 in human monocytes. On the other hand, Syk phosphorylation is elevated upon adherence of monocytes and this is further increased by OK-432 stimulation, as shown by Western blot. The Fc-receptor was also ruled out as a main receptor of the OK-432 monocyte response. In conclusion, TNF-alpha secretion is only found in monocytes removed from blood. This TNF-alpha secretion is not mediated through the beta(1-3)-integrin receptors. OK-432 may act as a target-seeking substance whereby only monocytes adhered, e.g. to a tumour cell, become cytotoxic in part explaining why OK-432 is well suited as a cancer treatment drug.

Male serum Chlamydia trachomatis IgA and IgG, but not heat shock protein 60 IgG, correlates with negatively affected semen characteristics and lower pregnancy rates in the infertile couple.

BACKGROUND: The objective of this study was to evaluate whether serum Chlamydia trachomatis immunoglobulin-A (IgA), IgM and C. trachomatis heat shock protein 60 (CHSP60) IgG are of additional value to C. trachomatis IgG regarding the impact on fecundity in infertile couples, and to relate C. trachomatis serum antibodies to semen characteristics, diagnoses and pregnancy outcome. METHODS: A total of 226 infertile couples, previously tested for C. trachomatis IgG, were tested for C. trachomatis IgA, IgM and CHSP60 IgG, and semen samples from all men were analysed. RESULTS: Chlamydia trachomatis serum IgA in men (but not in women) correlated with reduced chances of achieving pregnancy [p = 0.021, relative risk (RR) =0.65, 95% confidence interval (CI) 0.42-1.005] and in combination with C. trachomatis IgG the chance was further reduced (p =0.001, RR = 0.35, 95% CI 0.15-0.84). Chlamydia trachomatis serum IgA was also significantly correlated with reduced motility of the spermatozoa (-8.7%, p = 0.023), increased number of dead spermatozoa (+10.5%, p = 0.014) and higher prevalence of leucocytes in semen (+122%, p = 0.005), and in combination with C. trachomatis IgG positivity, there was also a decrease in sperm concentration (-35%, p = 0.033), the number of progressive spermatozoa (-14.8%, p = 0.029) and a rise in the teratozoospermia index (+4.4%, p = 0.010). CHSP60 IgG correlated with reduced motility (-5.6%, p = 0.033), and in the women to tubal factor infertility (p = 0.033), but no correlations of C. trachomatis serum IgM or CHSP60 IgG with pregnancy rates were found. CONCLUSIONS: Chlamydia trachomatis serum IgA in the male partner of the infertile couple has an additive value to IgG in predicting pregnancy chances, and serum IgA and IgG are associated with subtle negative changes in semen characteristics.

Modelling lateral beam quality variations in pencil kernel based photon dose calculations.

Standard treatment machines for external radiotherapy are designed to yield flat dose distributions at a representative treatment depth. The common method to reach this goal is to use a flattening filter to decrease the fluence in the centre of the beam. A side effect of this filtering is that the average energy of the beam is generally lower at a distance from the central axis, a phenomenon commonly referred to as off-axis softening. The off-axis softening results in a relative change in beam quality that is almost independent of machine brand and model. Central axis dose calculations using pencil beam kernels show no drastic loss in accuracy when the off-axis beam quality variations are neglected. However, for dose calculated at off-axis positions the effect should be considered, otherwise errors of several per cent can be introduced. This work proposes a method to explicitly include the effect of off-axis softening in pencil kernel based photon dose calculations for arbitrary positions in a radiation field. Variations of pencil kernel values are modelled through a generic relation between half value layer (HVL) thickness and off-axis position for standard treatment machines. The pencil kernel integration for dose calculation is performed through sampling of energy fluence and beam quality in sectors of concentric circles around the calculation point. The method is fully based on generic data and therefore does not require any specific measurements for characterization of the off-axis softening effect, provided that the machine performance is in agreement with the assumed HVL variations. The model is verified versus profile measurements at different depths and through a model self-consistency check, using the dose calculation model to estimate HVL values at off-axis positions. A comparison between calculated and measured profiles at different depths showed a maximum relative error of 4% without explicit modelling of off-axis softening. The maximum relative error was reduced to 1% when the off-axis softening was accounted for in the calculations.

Obstructive jaundice due to isolated tuberculosis of the pancreas: endoscopic treatment instead of surgery?

The optimal treatment for relieving biliary obstruction due to isolated pancreatic tuberculosis has not so far been defined, and most previously reported patients were treated surgically. We describe a 17-year-old, immunocompetent girl who was admitted with obstructive jaundice caused by a tuberculous mass in the head of the pancreas. Antituberculous therapy alone failed to alleviate the jaundice, and she was therefore treated by stent insertion and, subsequently, balloon dilation of the common bile duct stricture. At follow-up 5 years later, magnetic resonance cholangiopancreatography showed no evidence of stricture in the common bile duct.

The amount of treatment versus quality of life in patients formerly treated for head and neck squamous cell carcinomas.

The aim of the present study was to investigate the association between the self-reported quality of life (QoL) versus the initial TNM stage and amount of primary and recurrent tumor therapy given in a population of formerly treated head and neck squamous cell carcinoma (HNSCC) patients. We determined QoL by the European Organization for Research and Treatment of Cancer-Quality of Life Questionnaire (EORTC-QLQ) C30/H&N35 by structured interview. One hundred and twenty-two patients less than 80 years old, who had been diagnosed with HNSCC in western Norway in the period from 1992 to1997, and who had survived until 2000, were identified. Of these patients, 106 were eligible to be included. Ninety-six of these patients agreed to be interviewed. For TNM stage as well as the type of therapy given (local surgery, neck dissection or radiation therapy), T stage predicted the general QoL scores. Both increased TNM stage and all given tumor therapy seemingly caused lower H&N symptom QoL scores. Of the various tumor treatments employed, neck radiation therapy and neck dissection were indicated to be the most closely associated with the H&N QoL scores. Having neck dissection performed seemingly caused impairment beyond what was explained by the initial TNM stage. In conclusion, tumor therapy to HNSCC should not be restricted due to general QoL considerations. Further study of how and when to perform neck treatment is suggested in order to avoid unnecessary reduced H&N QoL.

Psychological coping style versus disease extent, tumour treatment and quality of life in successfully treated head and neck squamous cell carcinoma patients.

OBJECTIVES: To study self-reported coping style by the COPE questionnaire and the association to tumour node distant metastasis (TNM) stage, received treatment and health-related quality of life (HRQoL) in a population of successfully treated head and neck squamous cell carcinoma (HNSCC) patients. DESIGN: Disease free HNSCC patients were interviewed during a regular outpatient visit to the Department. SETTING: All patients <80 years who had been diagnosed with HNSCC, in Western Norway, in the period from 1992 to 1997 and who were disease free in the year 2000 were included. MAIN OUTCOME MEASURES: The HNSCC patients were studied by the European organization for research and treatment of cancer quality of life (QoL) questionnaire and by the COPE questionnaire from which coping styles profiles were extracted. Clinical and socio-demographic variables were also gathered. RESULTS: Level of problem focused coping style was associated with the T stage and whether or not the patient was given neck radiotherapy. An avoidance-focused coping style was generally associated with lowered HRQoL. Employment of emotional focused coping was associated with low HRQoL among the patients treated with surgery only, and associated with increased HRQoL among patients treated with radiation therapy only. The associations between HRQoL and coping style levels were stronger for HRQoL indexes reflecting cognitive/emotional function than for HRQoL indexes reflecting physical function. CONCLUSIONS: In former HNSCC patients, level of problem focused coping style was associated with the T stage and if given neck radiotherapy. Level of avoidance coping was inversely associated with the HRQoL, and level of emotional coping was associated with HRQoL in a complex manner.

Demonstration of Chlamydia trachomatis IgG antibodies in the male partner of the infertile couple is correlated with a reduced likelihood of achieving pregnancy.

BACKGROUND: The objective of this study was to determine the prevalence of Chlamydia trachomatis among both men and women seeking help at an infertility clinic, and to prospectively follow the effect of previous infection on pregnancy rates and pregnancy outcome after a long follow-up period (mean 37 months). METHODS: A total of 244 infertile couples was tested for C. trachomatis IgG antibodies, and IgG(+) couples were also tested for C. trachomatis DNA by PCR in a first-void urine sample. Study parameters were serology, PCR results, clinical diagnoses, treatments, pregnancy rates and pregnancy outcome. As controls, age-matched and spontaneously pregnant women were also tested with serology. RESULTS: The prevalence of IgG antibodies was 24.2, 20.1 and 15.6% among infertile women, infertile men and control women respectively. The prevalence of C. trachomatis DNA was 6.8 and 7.1% among tested women and men respectively. The presence of C. trachomatis IgG antibodies in women was related to tubal factor infertility (TFI) (P = 0.002). Decreased pregnancy rates were seen in couples where the man was IgG(+) (P = 0.005) with no relationship to TFI. Among women who achieved pregnancy, there was no difference in pregnancy outcome between IgG(+) or negative couples. CONCLUSIONS: C. trachomatis IgG antibodies in the man of the infertile couple was related to decreased pregnancy rates and to the presence of IgG antibodies in the woman. There was a high prevalence of asymptomatic persistent infections among infertile couples.