Single dose of 17ß-estradiol provides transient neuroprotection in female juvenile mice after cardiac-arrest and cardiopulmonary resuscitation.

Each year there are approximately 7000 out of hospital cardiac arrests in the pediatric population, with 30% resuscitation rate and a 6-10% rate of survival to hospital discharge. Survivors of cardiac arrest exhibit learning and memory deficits that are devastating during the school years. Delayed neuronal cell death occurs in the hippocampus following cardiac arrest and likely contributes to memory impairments. Circulating endogenous estrogen in young adult females has been shown to provide protection against ischemic cell death, as does chronic exogenous administration of 17ß-estradiol (E2). Chronic estrogen benefit can have undesirable feminizing effects, particularly in pre-adolescents. Here, we tested if a single-dose of E2 is neuroprotective in our pediatric cardiac arrest mouse model performed in juvenile mice. We subjected P21P25 C57Blk6 male and female mice to 8 min of cardiac arrest followed by cardiopulmonary resuscitation (CA/CPR). This developmental stage preceded the hormonal onset and serum estradiol and testosterone levels were not different in males and females. A single dose of E2 (100µg/kg) or vehicle was administered 30 min after resuscitation. Neuronal cell death measured 3 days after CA/CPR showed reduced hippocampal cell death in E2-treated females, but not males. Benefit of E2 in females was blocked by the P38 MAPK inhibitor, SB203580. Hippocampal-dependent memory function was equally impaired in E2-and vehicle-treated females measured in the contextual fear conditioning task at 7 days. Our findings demonstrate female-specific transient neuroprotection with E2 that does not provide sustained functional benefit.

Therapeutic hypothermia protects against ischemia-induced impairment of synaptic plasticity following juvenile cardiac arrest in sex-dependent manner.

Pediatric cardiac arrest (CA) often leads to poor neurologic outcomes, including deficits in learning and memory. The only approved treatment for CA is therapeutic hypothermia, although its utility in the pediatric population remains unclear. This study analyzed the effect of mild therapeutic hypothermia after CA in juvenile mice on hippocampal neuronal injury and the cellular model of learning and memory, termed long-term potentiation (LTP). Juvenile mice were subjected to cardiac arrest and cardiopulmonary resuscitation (CA/CPR) followed by normothermia (37°C) and hypothermia (30°C, 32°C). Histological injury of hippocampal CA1 neurons was performed 3days after resuscitation using hematoxylin and eosin (H&E) staining. Field excitatory post-synaptic potentials (fEPSPs) were recorded from acute hippocampal slices 7days after CA/CPR to determine LTP. Synaptic function was impaired 7days after CA/CPR. Mice exposed to hypothermia showed equivalent neuroprotection, but exhibited sexually dimorphic protection against ischemia-induced impairment of LTP. Hypothermia (32°C) protects synaptic plasticity more effectively in females, with males requiring a deeper level of hypothermia (30°C) for equivalent protection. In conclusion, male and female juvenile mice exhibit equivalent neuronal injury following CA/CPR and hypothermia protects both males and females. We made the surprising finding that juvenile mice have a sexually dimorphic response to mild therapeutic hypothermia protection of synaptic function, where males may need a deeper level of hypothermia for equivalent synaptic protection.

Increasing small conductance Ca2+-activated potassium channel activity reverses ischemia-induced impairment of long-term potentiation.

Global cerebral ischemia following cardiac arrest and cardiopulmonary resuscitation (CA/CPR) causes injury to hippocampal CA1 pyramidal neurons and impairs cognition. Small conductance Ca(2+)-activated potassium channels type 2 (SK2), expressed in CA1 pyramidal neurons, have been implicated as potential protective targets. Here we showed that, in mice, hippocampal long-term potentiation (LTP) was impaired as early as 3 h after recovery from CA/CPR and LTP remained impaired for at least 30 days. Treatment with the SK2 channel agonist 1-Ethyl-2-benzimidazolinone (1-EBIO) at 30 min after CA provided sustained protection from plasticity deficits, with LTP being maintained at control levels at 30 days after recovery from CA/CPR. Minimal changes in glutamate release probability were observed at delayed times after CA/CPR, implicating post-synaptic mechanisms. Real-time quantitative reverse transcriptase-polymerase chain reaction indicated that CA/CPR did not cause a loss of N-methyl-D-aspartate (NMDA) receptor mRNA at 7 or 30 days after CA/CPR. Similarly, no change in synaptic NMDA receptor protein levels was observed at 7 or 30 days after CA/CPR. Further, patch-clamp experiments demonstrated no change in functional synaptic NMDA receptors at 7 or 30 days after CA/CPR. Electrophysiology recordings showed that synaptic SK channel activity was reduced for the duration of experiments performed (up to 30 days) and that, surprisingly, treatment with 1-EBIO did not prevent the CA/CPR-induced loss of synaptic SK channel function. We concluded that CA/CPR caused alterations in post-synaptic signaling that were prevented by treatment with the SK2 agonist 1-EBIO, indicating that activators of SK2 channels may be useful therapeutic agents to prevent ischemic injury and cognitive impairments.

Clinic and genetic evaluation of variegate porphyria (VP) in a large family from the Balearic Islands.

Variegate porphyria (VP) (an autosomal dominant disease), is clinically characterized by skin photosensitivity and/or acute neurovisceral crises and biochemically by high levels of faecal protoporphyrin and coproporphyrin. It results from the partial deficiency of protoporphyrinogen oxidase (PPOX gene). Genetic heterogeneity has been reported in this gene, although no genotype-phenotype correlation has been evidenced. We have sequenced 27 members of a single large Majorcan family with several individuals that exhibit VP symptoms: two of the eight patients had only skin symptoms (25%), one patient had only acute visceral crises (12.5%), one patient had both manifestations (12.5%) and the rest were completely asymptomatic (50%). In eight individuals, a T>A transversion at the intron 6 consensus splicing site was found (IVS6+2T>A), but only four of them presented clinical symptoms. We have also detected four polymorphic positions, three non-coding and one non-synonymous coding: c.-414A>C; IVS2+121G>C; c.1188G>A and IVS12+34C>T. Although IVS12+34C>T change has been reported to cause VP, generalized linear model (GLM) analyses showed no significant association between these SNPs and phenotypic manifestations. Only three mtDNA haplogroups were detected in this family: H, K and U(5a1). Two of them are relatively common in Balearic Islands. Our family evidenced a positive correlation between the clinically overt VP and haplogroup H. Thus, it seems that, in this family, the haplogroup H could be involved in the expression of the disease. The GLM analyses evidenced an association between haplogroup H, mutation IVS6+2T>A and clinically overt variegate porphyria.

Genetic studies in variegate porphyria in Spain. Identification of gene mutations and family study for carrier detection.

BACKGROUND: First, to establish the mutations of the protoporphyrinogen-oxidase (PPOX) gene in four Spanish patients with variegate porphyria (VP). Second, study of carrier status detection in the families, including a four-generation Balearic family. Third, evaluation of the results of carrier detection screening methods. DESIGN: Blood samples of four patients and of 139 members belonging to four families, including four generations of a Balearic family were processed for mutation analysis of the 13 exons of PPOX gene. Biochemical studies were performed together (blood and faecal porphyrin analysis) and plasma fluorescence scanning for 626 nm peak emission detection. A questionnaire regarding clinical manifestations was submitted to all family members studied. RESULTS: Single strand conformational analysis (SSCP) of DNA allowed the detection of the following mutations: W224R, 746delT: exon 7, 1077-1082insC: exon 10, and IVS6+2T-->A. Mutation was present in 19 of the 139 members of the families studied. Clinical manifestations or biochemical alterations were checked in the carriers detected and found as not relevant or not present. Only 11 members of the 19 mutation-bearing individuals showed plasma fluorescence PV peak positivity. CONCLUSION: Demonstration of gene mutation is the most reliable means of detecting carriers in studies of variegate porphyria families. DNA analysis is the most sensitive carrier detection method and also allows transmission behaviour of the genetic defect to be established in successive generations of the affected families.

Diagnostic value of an ELISA using a recombinant 54-kDa species-specific protein from Chlamydia pneumoniae.

The aim of this study was to evaluate a 54-kDa recombinant protein encoded by the CPn0980 gene for use in a Chlamydia pneumoniae-specific ELISA. The ability of this affinity-purified protein to detect C. pneumoniae-specific antibodies was evaluated with a panel of 105 serum samples from 62 patients with community-acquired pneumonia. The results of this assay were compared with those obtained with a direct PCR-based detection assay and an outer-membrane complex-based immunoassay. The 54-kDa protein induced specific antibodies following infection of humans, and the recombinant 54-kDa ELISA detected anti-C. pneumoniae IgG and/or IgM antibodies with a sensitivity of 66.7% and a specificity of 79.2% compared with the direct PCR-based detection assay.

[Chest X-ray interpretation on patients admitted in a short-stay unit. Relation with the mean length of stay]. / Interpretación de la radiografía de tórax en los pacientes que ingresan en una unidad de estancia corta. Relación con la estancia media.

INTRODUCTION: To assess the agreement between physicians of the emergency department and a radiologist in the interpretation of chest roentgenograms in patients admitted to the short-stay unit, and to determine the effect of concordance on the mean length of stay. MATERIAL AND METHOD: The medical records of patients admitted to the short-stay unit over a 4-month period were reviewed. The interpretation of the chest X-ray film made by the physician in charge of the patient at the emergency department with that made by the radiologist was compared. The mean length of stay was determined and it was analyzed if the reading of the radiograph made by the radiologist before admission would decrease the length of stay. RESULTS: A total of 260 medical records were reviewed. The overall degree of agreement was 74.2% but it was greater when the physician at the emergency department was a staff physician or a resident in the final period of training than a resident in the initial period of training (82% vs 66.4%, p < 0.003). There were no statistically significant differences regarding the day hours at which readings were made. A change in the diagnosis and/or treatment of the patient would had occurred in only 9 cases (3.5%). There were no changes in the mean length of stay according to the presence or absence of concordance, although there was a trend towards an increase in the length of stay for those cases in which diagnosis and/or treatment would had been different. CONCLUSIONS: Readings of chest roentgenograms by a radiologist before admission to a short-stay unit does not appear to be justified for all patients, although it may be justified when a staff physician or a resident in the final period of training have doubts regarding interpretation of the radiographic images. A better supervision of residents in the initial period of training may contribute to improve the diagnostic reliability of chest X-ray films.

Chlamydia pneumoniae IgG serological status and venous thromboembolism: a cross-sectional hospital based study.

OBJECTIVE: To search for a link between Chlamydia pneumoniae serological status and venous thromboembolic disease. METHODS: From March 1992 to October 1999, we conducted a cross-sectional hospital-based study of consecutive unselected outpatients referred to us for clinical suspicion of venous thromboembolism. We compared the Chlamydia pneumoniae serological status with respectively, the venous thromboembolism, the deep vein thrombosis and the proximal deep vein thrombosis status. RESULTS: Among 1193 patients registered for suspected venous thromboembolism, 1010 samples were available (499 negative and 511 positive patients for venous thromboembolism). Seventy-nine patients were Chlamydia pneumoniae positive. Our work failed to demonstrate any clear association between Chlamydia pneumoniae and venous thromboembolism status. Nevertheless, we identified a statistical difference regarding Chlamydia pneumoniae seropositivity and proximal vein thrombosis status (adjusted odds ratio of 1.70, CI95%: 1.05 to 2.77). CONCLUSION: The presence of Chlamydia pneumoniae antibodies might be a minor risk factor for venous thrombosis.

[Chlamydia trachomatis urogenital infections in women. Best diagnostic approaches]. / Infections urogénitales féminines à Chlamydia trachomatis. Meilleures approches diagnostiques.

Chlamydiae are obligate intracellular bacteria. Chlamydia trachomatis is the most common sexually transmitted disease (STD). The C. trachomatis damaging disease sequelae such as sterility is based on intense and chronic inflammation elicited and maintained by reinfection or persistent infection. The high prevalence of C. trachomatis infection reflects the long and successful adaptation of these organisms to persist in their human host population. The large group of asymptomatically infected persons is not only at risk of serious long-term sequelae but also sustains transmission within communities. C. trachomatis acute infections have been diagnosed by cell culture, direct immunofluorescence, enzyme immunoassay, direct DNA hybridization, and more recently by nucleic acid amplification tests (NAATs). In chronic or persistent chlamydial infections, the level of Chlamydia is very low and bacteria are often not viable. Such infections would be characterized by continuing positive NAATs but only intermittent isolation of viable Chlamydia and positive assays for chlamydial protein antigen. The development of NAATs has been a major advance in the field of chlamydial diagnosis. The use of NAATs associated with serology test is the best diagnosis. The introduction of assays based on amplification of genetic material has subsequently increased the sensitivity of detecting chlamydial infections and offers the opportunity to use non-invasive sampling techniques to screen for infections in asymptomatic subjects. In this article, it was proposed the best diagnosis approaches for detection of acute and chronic infections.

Gene expression associated with in vivo induction of early phase-long-term potentiation (LTP) in the hippocampal mossy fiber-Cornus Ammonis (CA)3 pathway.

Affymetrix microarray technology was used to characterize whole-hippocampus gene expression associated with in vivo N-methyl-D-aspartate (NMDA)-R-independent long-term potentiation (LTP) in the mossy fiber (MF)-Cornus Ammonis (CA)3 pathway of adult male F344 rats. Acute MF responses were evoked by stimulation of the MF bundle and recorded in stratum lucidum of CA3. Following recording of baseline responses at 0.05 Hz, animals received either CPP (NMDA-R antagonist, 10 mg/kg) or naloxone (opioid-R antagonist, 10 mg/kg). LTP was induced by two 100 Hz 1-sec trains at the intensity sufficient to evoke 50% of the maximal response. Responses were collected for an additional hour. In controls, MF responses were collected at 0.05 Hz for 1 hr, but 100 Hz trains were not delivered. Hippocampi were harvested prior to total RNA isolation. Fragmented cRNA was hybridized to a rat U34 neurobiology array. F344 rats exhibited characteristic LTP in the presence of CPP and LTP blockade in the presence of naloxone. As a result, genes associated with both NMDA-independent LTP and naloxone-induced blockade were identified. These include genes involved in transmitter transport, intracellular messengers, growth factors and ion channels. Up-regulated include NMDA-R2D, neuropeptide Y (NPY), proenkephalin, BDNF and NGFR. Down-regulated genes include IGF-1 and GABA-B.

[Systematic screening for Chlamydia trachomatis with the molecular biological AMP-CT test in urine samples from young women]. / Recherche systématique de Chlamydia trachomatis dans l'urine d'une population de femmes jeunes par biologie moléculaire AMP-CT.

OBJECTIVE: We report the results of a systematic direct detection screening protocol for Chlamydia trachomatis in urine samples from young women. MATERIAL AND METHOD: The study included 1026 patients aged 13 to 30 years. Urine samples were tested with a molecular biology assay: AMP-CT. RESULTS: Thirty-five patients (3.4%) were positive: 80% of the positive patients were aged less than 25 years, 48.6% less than 20 years. All these patients were treated and post treatment controls were negative. CONCLUSION: This study suggests that national screening programs for Chlamydia trachomatis could be beneficial for women aged between 15 and 25 years and that the "Calmat" law could be modified in consequence.

[Submitral annular aneurysm, postpartum cardiomyopathy, and anti-Chlamydia pneumoniae antibodies in Niamey (Niger)]. / Anevrisme annulaire sous-mitral, cardiomyopathie postpartum et anticorps anti-Chlamydia pneumoniae a Niamey (Niger).

Idiopathic annular submitral left ventricular aneurysm has been described mainly in young Africans living in tropical countries. Association with peripartum cardiomyopathy has been previously pointed out. The purpose of this report is to describe 3 patients with idiopathic annular submitral left ventricular aneurysm identified in a series 50 patients with peripartum cardiomyopathy in Niamey, Republic of Niger. Anti-Chlamydia pneumoniae antibody status was determined in all 50 patients using the micro-immunofluorescence technique that differentiates IgG, IgA and IgM antibodies. Findings showed that all 3 patients with annular submitral left ventricular aneurysm had significantly elevated plasma IgG and IgA anti-Chlamydia pneumoniae antibody levels at the time of diagnosis. In one patient analysis of 2 samples collected 3 months apart indicated chronic elevation with exceptionally high IgG antibody levels (1/2048e). These previously unreported data suggest a possible link between Chlamydia pneumoniae and development of peripartum cardiomyopathy and annular submitral left ventricular aneurysm. This possibility is supported by recent evidence that specific IgA anti-Chlamydia pneumoniae antibodies may be predictive of aortic abdominal aneurysms.

Chlamydia trachomatis and male infertility in Tunisia.

OBJECTIVE: Chlamydia trachomatis is a common sexually transmitted micro-organism. The impact of chlamydial infection on semen parameters and male fertility is controversial. Our purpose was to determine the prevalence of C. trachomatis in the male partners of infertile couples in Tunisia and to assess the relationship between chlamydial infection markers and male infertility. METHODS: Chlamydial DNA in urethral and in semen specimens was determined by using the Cobas Amplicor polymerase chain reaction (PCR) assay and chlamydial immunoglobulin G (IgG) antibodies were measured by micro-immunofluorescence in serum samples in 92 male partners, with or without pathological standard semen parameters, according to the guidelines of the World Health Organization (sperm count, progressive sperm motility, sperm morphology and sperm viability). In parallel, chlamydial infection markers in endocervical material were determined by PCR and chlamydial IgG antibodies were measured by micro-immunofluorescence in serum samples from the female partners of the patients. RESULTS: C. trachomatis was found in 35.9% (33/92) of the male partners of the infertile couples and in 38% (35/92) of their female partners. There was a significant correlation between the detection of C. trachomatis in both partners (p = 0.004). C. trachomatis DNA was detected in 18.5% (17/92) of urethral specimens and in 16.3% (15/92) of semen specimens. Chlamydial IgG antibodies were present in 9.8% (9/92) of the serum samples. A standard semen analysis showed that 88% (81/92) were pathological. Sperm viability, progressive sperm motility, morphology and sperm concentration were abnormal in 73.8%, 70.2%, 34.5% and 13%, respectively, of the 92 evaluated semen specimens. Comparison of the parameters of the standard semen analysis between the male partners of the infertile couples with or without chlamydial infection markers showed that only the presence of C. trachomatis DNA in semen samples can affect sperm motility. Parameters of the standard semen analysis were not significantly related either to the detection of chlamydial DNA in urethral samples or to the presence of serum chlamydial antibodies. CONCLUSION: Our results show that C. trachomatis seems to be widespread among the male partners of infertile couples in Tunisia and show that this organism can affect sperm motility and, thus, can play an important role in the etiology of male infertility.

Detection of Chlamydia trachomatis in semen and urethral specimens from male members of infertile couples in Tunisia.

The sequelae to infection with Chlamydia trachomatis in women are an established cause of tubal infertility. However, little is known about chlamydial infection and male infertility. The main objective of this study was to evaluate the presence of asymptomatic C. trachomatis infections in urethral and semen specimens from the male members of infertile couples by means of four different methods: the direct fluorescence antibodies assay, cell culture, the Roche Cobas Amplicor polymerase chain reaction, and the presence of chlamydial local IgA antibodies by the recombinant antibody-enzyme-linked immunosorbent assay. One or more chlamydial infection markers were detected in 42 (45.7%) of the 92 examined urethral and semen specimens from the male partners of infertile couples. C. trachomatis was detected in 23.9% (22/92) of urethral specimens and in 35.9% (33/92) of semen specimens. Although there was a significant correlation between the detection of one or more chlamydial infection markers in urethral and semen specimens (p = 0.01), no significant correlation was found between the detection of C. trachomatis DNA in these samples. Furthermore, no significant association was found between the presence of chlamydial local IgA antibodies and the detection of C. trachomatis. The discrepancies in positive results found between some techniques for the detection of C. trachomatis in urethral and semen specimens might be explained by variations in the sensitivities and specificities of the tests carried out and the use of specimens from different anatomical locations. Our findings suggest that C. trachomatis seems to be widespread among the male partners of infertile couples in Tunisia. The detection of C. trachomatis in urethral or semen specimens can serve as a marker for the presence of this organism in the genital tract, which is not necessarily the cause of male infertility. The study of the correlation between the detection of chlamydial infection markers and the parameters of male fertility seems to be necessary in order to determine the direct link between chlamydial infection and male infertility and to choose the most efficient technique and most suitable specimen with which to diagnose C. trachomatis-associated male infertility.

[The relationship between Chlamydia pneumoniae and atherosclerosis]. / Les liens entre Chlamydia pneumoniae et athérosclérose.

BACKGROUND: Risk factors for arthrosclerosis have been well identified. More than ten years ago, an infectious process was incriminated, particularly the pathogenic effect of Chlamydia pneumoniae in the development of atheromatous lesions responsible for ischemic cardiovascular diseases. DATA BASES: Several approaches have been used to assess the presence of a relationship between C. pneumoniae and the development of cardiovascular disease. Serological, histopathological (study of the atheromatous plaque), pathophysiological, and finally animal studies using models reproducing the human disease have generally favored an association. Therapeutic trials, especially those testing roxithromycin or azithromycin have demonstrated the action of secondary prevention of ischemic heart disease (unstable angina, myocardial infarction). CONCLUSION: The notion of an association between these two factors is biologically plausible. Several points remain to be clarified, particularly the need to develop a reliable diagnostic method for C. pneumoniae infections. It would also be useful to prove the viability of the pathogen within atheromatous plaques and finally to design studies of immune response to C. pneumoniae infections. Prospective therapeutic trials for primary prevention of cardiovascular disease would be most informative but would be most difficult to conduct.

[Chlamydia infection and peripartum dilated cardiomyopathy in Niger]. / Infection à Chlamydia et cardiomyopathie dilatée peripartum au Niger.

Peripartum cardiac failure due to cardiomyopathy is common in sub-saharan Africa. The etiology is unknown. This study was performed in Niger to assess a possible relationship between peripartum cardiomyopathy and Chlamydia. A total of 50 African women presenting peripartum cardiomyopathy underwent testing for infection by Chlamydia pneumoniae, Chlamydia trachomatis, and Chlamydia psittaci. The inclusion criteria were cardiac failure during the last three months of pregnancy or first 6 months postpartum with echocardiographic evidence of dilated cardiomyopathy. Similar testing was carried out in a control group of 25 African women from the same geographical location without cardiac disease. Detection of specific IgG, IgA and IgM antibodies was performed using the microimmunofluorescence technique. The cut-off values were > or = 1/32 for specific IgG antibody and > or = 1/16 for specific IgA and IgM antibody. Statistical comparison of the patient and control groups was achieved using the chi 2 test. For Chlamydia pneumoniae, 48 patients (96 p. 100) versus 20 controls (80 p. 100) controls were positive for IgG antibodies (p < 0.025) and 39 patients (80 p. 100) versus 14 controls (56 p. 100) were positive for IgA antibodies (p < 0.05). No patient or control demonstrated IgM antibodies for Chlamydia pneumoniae. For Chlamydia trachomatis and Chlamydia psittaci, differences in positive rates were not statistically significant. This is the first study demonstrating infection in patients with peripartum cardiomyopathy. The possible role of Chlamydia pneumoniae is discussed.

Effect of prior exposure to Chlamydia pneumoniae, Helicobacter pylori, or cytomegalovirus on the degree of inflammation and one-year prognosis of patients with unstable angina pectoris or non-Q-wave acute myocardial infarction.

Inflammation and chronic infections may be important features in the pathogenesis of acute coronary syndromes. We describe 6 systemic markers of inflammation in patients with unstable angina or non-Q-wave myocardial infarction and the relations between these markers, seropositivity to chronic infections, and prognosis. C-reactive protein (CRP), serum amyloid A protein (SAA), fibrinogen, interleukin-6 (IL-6), neopterin, procalcitonin, and serum antibody levels to Chlamydia pneumoniae, Helicobacter pylori, and cytomegalovirus were measured on admission and 48 hours later. One-year clinical follow-up was performed. Plasma levels of acute phase reactants were all elevated on admission and increased further at 48 hours: CRP from 10.1 +/- 2.1 mg/L at baseline to 26.6 +/- 5.1 mg/L at 48 hours (p <0.001); SAA from 27.3 +/- 8.5 to 93.1 +/- 23.2 mg/dl (p <0.005); fibrinogen from 3.2 +/- 0.1 to 3.8 +/- 0.1 g/L (p <0.0001); whereas initial high levels of IL-6 tended also to increase from 9.8 +/- 2 to 15.3 +/- 3.1 pg/ml (p = NS). In contrast, neopterin and procalcitonin remained unchanged. We found no association between levels of each inflammatory marker and the serologic status. Furthermore, levels of inflammatory proteins in patients seronegative to all 3 agents were comparable to those of patients seropositive to 2 or 3 infectious agents. The composite end points of death, myocardial infarction, recurrent angina, or revascularization at 1-year follow-up did not differ according to the serologic status. Thus, in patients with acute coronary syndromes, the acute phase proteins increased over the first 2 days of hospitalization. This initial inflammatory reaction as well as the 1-year clinical outcome did not differ according to the initial serologic status of Chlamydia pneumoniae, Helicobacter pylori, or cytomegalovirus.

Chlamydia pneumoniae serology: interlaboratory variation in microimmunofluorescence assay results.

The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.