Variations in atrial fibrillation ablation utilization and reimbursement among medicare beneficiaries: an observational study from 2013 to 2019

Background

Atrial fibrillation (AF) pulmonary vein isolation ablation has been utilized increasingly yet variably in the USA.

Purpose

To identify variations in AF ablation utilization and reimbursement among Medicare beneficiaries (MB).

Methodology

We used a 100% sample of MB who underwent AF ablation from 2013 to 2019. We stratified data geographically (Northeast, South, West, and Midwest), identified the mean AF prevalence and the number of AF ablations per 100,000 MB, and examined the correlation between AF prevalence and ablation. We also examined the number of cardiologists performing AF ablation per 100,000 MB and the average number of AF ablation per individual cardiologist (ablation/cardiologist), as well as average submitted charge (ASC) for AF ablation. Additionally, we stratified data per urban versus rural areas as well as the gender of performing cardiologists and examined ablation/cardiologist and the ASC.

Results

Geographic analysis: The mean AF prevalence, the rates AF ablation per 100,000 MB, the number of cardiologists per 100,000 MB, and ablation/cardiologist have shown a steady increase in all regions across years. In all years, the mean AF prevalence was significantly different among regions with the highest prevalence in the Northeast and the lowest in the West (all P<0.001), however, there was no significant difference in the rates of AF ablation per 100,000 MB (all P≥0.056). There was significant correlation between AF prevalence and ablation only in the Midwest and the West, with 46.4% and 43.4% positive correlation respectively (P≤0.0001). The number of cardiologists performing AF ablation per 100,000 MB was not significantly different among regions in all years (All P≥0.48), however, ablation/cardiologist was significantly higher in the West and the South compared to the Northeast and the Midwest (All P<0.0001). On the contrary, the ASC has shown steady decrease in all regions. The ASC was significantly different among regions in all year (all P≤0.003) with higher ASC in the Midwest and the Northeast compared to the south and the West.

Urban vs rural analysis: Ablation/cardiologist was not significantly different between urban and rural areas in all years (all P≥0.068) except in 2013 when it was significantly higher in urban areas (P=0.004). The ASC was significantly higher in rural areas only in 2015 and 2019 (P=0.037 and P=0.029 respectively) however, there was no significant difference in the rest of the years (P≥0.07).

Gender analysis: Ablation/cardiologist was not significantly different between male and female cardiologists in all years (P≥0.056) except in 2017 when the average was significantly higher per male cardiologists (P=0.007). The ASC was not significantly different in all years (P≥0.362).

Conclusion

There are variations in AF ablation utilization and reimbursement among MB in the USA according to geographic, urban and rural regions, and the gender of performing cardiologists.

Funding Acknowledgement

Type of funding sources: None.

PDGFRβ promotes oncogenic progression via STAT3/STAT5 hyperactivation in anaplastic large cell lymphoma

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin T cell lymphoma commonly driven by NPM-ALK. AP-1 transcription factors, cJUN and JUNb, act as downstream effectors of NPM-ALK and transcriptionally regulate PDGFRβ. Blocking PDGFRβ kinase activity with imatinib effectively reduces tumor burden and prolongs survival, although the downstream molecular mechanisms remain elusive.

METHODS AND RESULTS

In a transgenic mouse model that mimics PDGFRβ-driven human ALCL in vivo, we identify PDGFRβ as a driver of aggressive tumor growth. Mechanistically, PDGFRβ induces the pro-survival factor Bcl-xL and the growth-enhancing cytokine IL-10 via STAT5 activation. CRISPR/Cas9 deletion of both STAT5 gene products, STAT5A and STAT5B, results in the significant impairment of cell viability compared to deletion of STAT5A, STAT5B or STAT3 alone. Moreover, combined blockade of STAT3/5 activity with a selective SH2 domain inhibitor, AC-4-130, effectively obstructs tumor development in vivo.

CONCLUSIONS

We therefore propose PDGFRβ as a novel biomarker and introduce PDGFRβ-STAT3/5 signaling as an important axis in aggressive ALCL. Furthermore, we suggest that inhibition of PDGFRβ or STAT3/5 improve existing therapies for both previously untreated and relapsed/refractory ALK+ ALCL patients.

A versatile Johansson-type tender x-ray emission spectrometer

We present a high energy resolution x-ray spectrometer for the tender x-ray regime (1.6-5.0 keV) that was designed and operated at Stanford Synchrotron Radiation Lightsource. The instrument is developed on a Rowland geometry (500 mm of radius) using cylindrically bent Johansson analyzers and a position sensitive detector. By placing the sample inside the Rowland circle, the spectrometer operates in an energy-dispersive mode with a subnatural line-width energy resolution (∼0.32 eV at 2400 eV), even when an extended incident x-ray beam is used across a wide range of diffraction angles (∼30° to 65°). The spectrometer is enclosed in a vacuum chamber, and a sample chamber with independent ambient conditions is introduced to enable a versatile and fast-access sample environment (e.g., solid/gas/liquid samples, in situ cells, and radioactive materials). The design, capabilities, and performance are presented and discussed.

<b>New distribution records of some wild crop relatives from India</b>

Field surveys across various parts of the country coupled with an analysis of literature and examination of herbarium specimens revealed the natural distribution of six wild relatives of crop species in various states/union territories of India, viz., Cajanus scarabaeoides (from Lakshadweep), Cucumis javanicus (from Meghalaya), Hystrix duthiei (from Jammu & Kashmir), Luffa echinata (from Haryana) and Trichosanthes pilosa (from Andhra Pradesh), which have not been reported earlier from these states.  Their descriptions, phenology, habitat and other field notes have been presented here.

Estimation of limiting availability for a stationary bivariate process

We estimate the limiting availability of a system when the operating and repair times form a stationary bivariate sequence. These estimators are shown to be consistent and asymptotically normal under certain conditions. In particular, we estimate the limiting availability for a bivariate exponential autoregressive process.

Clinical and demographic characteristics predictive of treatment outcomes for certolizumab pegol in moderate to severe Crohn's disease: analyses from the 7-year PRECiSE 3 study

BACKGROUND

Clinical factors were previously identified as predictors of short-term treatment efficacy in Crohn's disease (CD). The PRECiSE 3 (P3) 7-year trial provides an opportunity to study predictors of short- and long-term clinical remission among CD patients treated with certolizumab pegol (CZP).

AIM

To identify factors that influence long-term remission of CD with CZP treatment.

METHODS

Patients who had completed placebo-controlled studies (PRECiSE 1/PRECiSE 2, P1/P2) enrolled in P3 and received open-label CZP 400 mg every 4 weeks up to 7 years. Baseline predictors included, but were not limited to, smoking status, disease duration, prior inflammatory bowel disease (IBD) surgery, Harvey-Bradshaw Index (HBI), albumin, haematocrit and CZP exposure; association with time to initial remission (HBI ≤4) was tested for patients who received CZP in P1/P2; time to loss of remission/frequency of maintenance of remission was also tested. Univariate analyses and multivariate Cox or logistic regression models were used.

RESULTS

Predictors for initial remission (N = 377) included age, haematocrit, prior IBD surgery and entry HBI (P < 0.05 for all). Predictors for loss of remission (N = 437) included HBI, serum albumin concentration, haematocrit, smoking status and exposure. Predictors of maintenance of remission (N = 437) included haematocrit, IBD surgery, HBI, disease duration, serum albumin concentration and exposure. Significant predictors were confirmed with stepwise multivariate regression models.

CONCLUSIONS

These analyses identified several influential parameters for short-and long-term remission of Crohn's disease with certolizumab pegol treatment. The data yield valuable hypotheses regarding factors that influence certolizumab pegol treatment. More investigation is needed. (ClinicalTrials.gov identifier NCT00552058).

Foreign body ingestions in a schizophrenic patient

The topic of foreign body ingestion has received extensive coverage in the areas of surgery, emergency medicine and pediatrics. A subset of this topic, the intentional ingestion of foreign bodies, however, is much less common, and involves subtleties in evaluation and management not usually seen in accidental ingestions. Here, we report a case of ingestion of a rolled, metal tuna can lid in a male prison inmate previously diagnosed with depression and paranoid schizophrenia. Following evaluation by the surgical team, the foreign body was removed by laparotomy and the patient was discharged back to the prison without complication. In many cases, ingestions ofthis type involve a command hallucination ordering the patient to swallow the foreign body. Interestingly, the patient in the present case reported auditory hallucinations commanding him not to swallow the can lid.

Estimation of distribution function in bivariate competing risk models

We consider lifetime data involving pairs of study individuals with more than one possible cause of failure for each individual. Non-parametric estimation of cause-specific distribution functions is considered under independent censoring. Properties of the estimators are discussed and an illustration of their application is given.

Proliferative myositis in a patient with AIDS

We report a case of proliferative myositis in the right biceps of a 56-year-old man with acquired immune deficiency syndrome (AIDS). Imaging methods included sonography, computed tomography and magnetic resonance imaging. The diagnosis was made by a core-cut biopsy and fine needle aspiration biopsy with immunohistochemical analysis. The lesion disappeared after 2 months without treatment. It is particularly important to determine whether intramuscular masses arising in patients with AIDS are due to an infectious or malignant process.

Occurrence of Escherichia coli O157 in Raw Material and Food in Czech Republic

The study was carried out to investigate the incidence of Escherichia coli O157 in raw materials, foodstuffs and the agricultural environment. Of a total of 987 samples examined, 22 strains (2.2%) were identified as E. coli O157 and 10 of them as E. coli O157:H7. Cefixime-Tellurite MacConkey sorbitol agar (CT-SMAC) agar and Biosynth culture medium (BCM) E. coli O157:7 medium were used for the isolation. The virulence factors (stx1, stx2, eae, and ehxA genes) were identified by polymerase chain reaction (PCR). Most strains were isolated from the mechanically deboned poultry meat (nine), minced meat (six) and raw milk (four). One strain was isolated from beef carcass and two strains from waste water. No strains were were found in mass for sausages, refreshment salads, swabs of pork and poultry carcasses and faeces of cattle and pigs. Ten strains from the 22 identified proved to be positive for all factors of virulence. They were isolated from minced meat (four), raw milk (four), waste water (one) and swab from beef carcass (one). Sensitivity to the antimicrobial drugs ampicillin (AMS), ampicillin-sublactam (SAM), tetracycline (TET), ofloxacine (OFL), cefuroxime (CRX), chloramphenicol (CPM), gentamicine (GEN), colistin (COL), cephalozine (CLZ), cefoxitin (CXT), aztreonam (AZT), and sulphamethoxazole + trimethoprim (COT) was tested using the standard dilution technique and disc diffusion test. Minimum inhibitory concentrations (MIC) characteristics (MIC(50), MIC(90), MIC range) and inhibitory zone diameter were determined for each strain. As determined by MICs, the resistance to tested antibiotics in E. coli O157 isolates was found to AMS (90.9%), CLZ (81.8%), CRX (63.6%), CXT (72.7%), CPM (72.7%), TET (81.8%), SAM (59.1%), COT (9.1%), COL (63.61%), AZT (9%) and GEN (4.5%). The similar results were obtained using the disc diffusion method. The differences were found relating to SAM, CXT, CMO and TET. Resistance against one or more antibiotics was found in 95.4% of E. coli O157. Only one strain was susceptible to all tested antibiotics. Most of the strains were resistant to ampicillin and cephalozine. Eight different resistance phenotypes were demonstrated in E. coli O157.

Ganciclovir resistance mutations in UL97 and UL54 genes of Human cytomegalovirus isolates resistant to ganciclovir

Human cytomegalovirus (HCMV) resistance to ganciclovir results from mutations in viral phosphotransferase (UL97) and/or DNA polymerase (UL54) genes. The HCMV isolates from the blood of immunocompromised patients with persisting presence of the pp65 antigen in the blood in spite of ganciclovir therapy were tested for ganciclovir susceptibility by an immediate-early antigen plaque reduction assay, and the UL54 and UL97 genes were sequenced. Nine isolates from eight patients (six patients with acquired immune deficiency syndrome (AIDS), one liver transplant recipient and one renal transplant recipient) showed phenotypic resistance to ganciclovir. All these ganciclovir-resistant HCMV isolates harbored one or more of the following UL97 mutations: M460V, A594V, A594T, L595S, C603W, and M615V. Two isolates harbored the P522S mutation in the UL54 gene. The M615V mutation in the UL97 gene has not been reported earlier and its role in ganciclovir resistance remains to be elucidated. In ganciclovir-resistant HCMV isolates the UL54 gene was less frequently mutated than the UL97 gene. The P522S mutation was relatively frequent in UL54-mutated HCMV isolates.

Paediatric renal transplantation--a 15 year experience

OBJECTIVE

To review the outcome of paediatric renal transplantation over a period of 15 years in a developing country.

METHODS

This is a retrospective study of 63 children, less than 15 years of age, who underwent living-related renal transplantation in Christian Medical College and Hospital Vellore between 1984 and 1996.

RESULTS

The records of 12 patients were not adequate for detailed analysis. Parents were the donors for these children in 84.3% of cases. The most common known cause of end-stage renal disease in these children was reflux nephropathy. Combinations of cyclosporine, azathioprine and prednisolone were used as immunosuppressive drugs. Complications occurred in 16 patients. During the follow-up period, eight patients died and two returned to receiving haemodialysis. Patient survival was 92% at the end of 1 year and 90% at the end of 3 years. Graft survival was 88% and 86% at 1 and 3 years, respectively.

CONCLUSION

Our study validates the concept of renal transplantation as optimal therapy with adequate medical, social and functional rehabilitation for children with end-stage renal disease. Our study also indicates that vesicoureteric reflux appears to be underdiagnosed and should be actively pursued to prevent complications.

Pre- and in-hospital management of community-acquired pneumonia in southern France, 1998-99

A prospective, hospital-based, multicenter study was undertaken to identify the reasons for hospital admission, to describe antibiotic treatment before and during hospitalization, and to determine the outcome of community-acquired pneumonia (CAP). Data collected included prehospital management of CAP, Pneumonia Outcome Research Team (PORT) classification on admission, in-hospital antibiotic treatment, and predictors of death within 30 days. Among the 215 patients (mean age, 66.7 years; M:F ratio, 1.1) recruited, 24 (11.2%) were living in nursing homes. CAP had been diagnosed prior to admission in 55 (25.6%) patients. At admission, 75 (34.9%) patients had a low risk of death (PORT classification I-II). A pathogen was isolated for 55 (25.6%) patients, primarily Streptococcus pneumoniae (n=18), atypical agents (n=16), influenza virus (n=10), and respiratory syncytial virus (n=4). Amoxicillin (with or without clavulanate), cefotaxime, or ceftriaxone monotherapy was prescribed to 121 (56.3%) patients. Dual combination therapy was prescribed to patients at higher risk of death (PORT classification III-V; OR, 3.09). Mortality was 7%. Logistic-regression analysis identified nursing-home residency (OR, 8.36), serum creatinine > or =88 micromol/l (OR, 7.88), and Pneumonia Outcome Research Team classification (OR, 1.02) as independent predictors of death. CAP remains a serious disease for elderly persons living in nursing homes. This population should benefit from immunization with pneumococcal and influenza vaccines.

Mechanisms of photoinitiated cleavage of DNA by 1,8-naphthalimide derivatives

Using water-soluble 1,8-naphthalimide derivatives, the mechanisms of photosensitized DNA damage have been elucidated. Specifically, a comparison of rate constants for the photoinduced relaxation of supercoiled to circular DNA, as a function of dissolved halide, oxygen and naphthalimide concentration, has been carried out. The singlet excited states of the naphthalimide derivatives were quenched by chloride, bromide and iodide. In all cases the quenching products were naphthalimide triplet states, produced by induced intersystem crossing within the collision complex. Similarly, the halides were found to quench the triplet excited state of the 1,8-naphthalimide derivatives by an electron transfer mechanism. Bimolecular rate constants were < 10(5) M-1 s-1 for quenching by bromide and chloride. As expected from thermodynamic considerations quenching by iodide was 6.7 x 10(9) and 8.8 x 10(9) M-1 s-1 for the two 1,8-naphthalimide derivatives employed. At sufficiently high ground-state concentration self-quenching of the naphthalimide triplet excited state also occurs. The photosensitized conversion of supercoiled to circular DNA is fastest when self-quenching reactions are favored. The results suggest that, in the case of 1,8-naphthalimide derivatives, radicals derived from quenching of the triplet state by ground-state chromophores are more effective in cleaving DNA than reactive oxygen species or radicals derived from halogen atoms.

A prospective, randomized, comparative US trial of a combination hepatitis A and B vaccine (Twinrix) with corresponding monovalent vaccines (Havrix and Engerix-B) in adults

In an open, randomized, multicenter, controlled clinical trial in the US, 773 adults were administered either a combination hepatitis vaccine (Twinrix: 720 EL.U inactivated hepatitis A antigen and 20 mcg recombinant hepatitis B surface antigen per milliliter) on a 0, 1, 6 month schedule or corresponding monovalent vaccines concurrently (Havrix, 1440 EL.U/ml of hepatitis A antigen at 0, 6 months and Engerix-B, 20 mcg of hepatitis B surface antigen at 0, 1, 6 months). Non-inferiority testing for the primary endpoint, severe soreness, and equivalence testing for the secondary endpoints, anti-HAV seroconversion and anti-HBs seroprotection, showed that safety and immunogenicity were comparable in the two groups.

A novel extractionless hplc fluorescence method for the determination of glyburide in the human plasma: application to a bioequivalence study

PURPOSE

To develop a simple, sensitive and rapid HPLC fluorescence method with single step sample preparation for the determination of glyburide in the human plasma.

METHODS

Glyburide and ketoconazole (internal standard) were extracted from the 0.5 mL plasma by addition of 0.5 mL acetonitrile and 50 microL CuSO(4) solution (5% w/v in water). The separation was achieved on the Kingsorb 3 microm, C8 reverse phase column at ambient temperature with a mobile phase consisted of 45% buffer solution (0.05 M NH(4)H(2)P(4)), 40% acetonitrile and 15% methanol adjusted to pH 5.7 by diluted ammonia solution. A fluorescence detector was set at 235 nm excitation wavelength and 354 nm emission wavelengths to monitor eluted components.

RESULTS

The internal standard and glyburide eluted at about 6.7 and 9.6 min, respectively at the flow rate of 1 mL/min. The regression equation was established for every calibration curves (5 ng/mL to 400 ng/mL), which resulted in the correlation coefficient of 0.99 or greater. The absolute recovery ranged from 94.32 to 98.12% and the relative recovery ranged from 91.12 to 97.15%. The intraday coefficient of variation (CV) ranged from of 6.52 to 12.35% and interday varied from 6.21 to 16.07%. The limit of quantitation (LOQ) of glyburide was set to five ng/mL.

CONCLUSION

This simple, rapid and sensitive method is suitable for pharmacokinetic, bioavailability and biequivalence studies.

[Thrombotic microangiopathy during HIV infection. A retrospective study performed in infectious diseases units in southern France]

OBJECTIVES

To describe and analyze the clinical and biological manifestations of thrombotic microangiopathy (TMA) and evaluate the therapeutic strategies.

METHODS

A retrospective study was performed in 14 infectious diseases units of southern France. All HIV patients presenting TMA during the last decade were selected (n = 14).

RESULTS

The principle signs observed, aside from defining TMA (association of microangiopathic hemolytic anemia, thrombocytopenia and renal failure), were diarrhea (n = 9) and a high level of lacticodehydrogenase (LDH). Patients were at an advanced stage of HIV infection (median of CD4+ cells counts = 70/mm3). Specific etiology was identified in 7 cases: bacterial infection (n = 5), CMV retinitis associated with Kaposi's sarcoma (n = 1) and intravenous drug use (n = 1). Various treatments were used: plasmatic exchange (5 cases), fresh frozen plasma (6 cases), steroid therapy (4 cases), acetyl salicylic acid (3 cases), adaptation of antiretroviral treatment (3 cases). The global prognostic was poor with 50% mortality within 2 months. A high level of LDH (> 2500 UI/L) was associated with premature death in 5 of the 6 cases observed.

CONCLUSION

Our data confirm the severity of TMA in case of HIV infection. The common treatment remains the use of plasmatic exchange and fresh frozen plasma; an optimal antiretroviral therapy must be associated.

Signaling mediated by the cytosolic domain of peptidylglycine alpha-amidating monooxygenase

The luminal domains of membrane peptidylglycine alpha-amidating monooxygenase (PAM) are essential for peptide alpha-amidation, and the cytosolic domain (CD) is essential for trafficking. Overexpression of membrane PAM in corticotrope tumor cells reorganizes the actin cytoskeleton, shifts endogenous adrenocorticotropic hormone (ACTH) from mature granules localized at the tips of processes to the TGN region, and blocks regulated secretion. PAM-CD interactor proteins include a protein kinase that phosphorylates PAM (P-CIP2) and Kalirin, a Rho family GDP/GTP exchange factor. We engineered a PAM protein unable to interact with either P-CIP2 or Kalirin (PAM-1/K919R), along with PAM proteins able to interact with Kalirin but not with P-CIP2. AtT-20 cells expressing PAM-1/K919R produce fully active membrane enzyme but still exhibit regulated secretion, with ACTH-containing granules localized to process tips. Immunoelectron microscopy demonstrates accumulation of PAM and ACTH in tubular structures at the trans side of the Golgi in AtT-20 cells expressing PAM-1 but not in AtT-20 cells expressing PAM-1/K919R. The ability of PAM to interact with P-CIP2 is critical to its ability to block exit from the Golgi and affect regulated secretion. Consistent with this, mutation of its P-CIP2 phosphorylation site alters the ability of PAM to affect regulated secretion.

A comparison of two commercial recombinant vaccines for hepatitis B in adolescents

The immunogenicity and reactogenicity profiles of three doses each of Engerix-B(R) (10 microg hepatitis B surface antigen) and Recombivax(R) (5 microg hepatitis B surface antigen), given on a 0, 1, 6 month schedule to healthy adolescents were compared in a single-blind, randomized clinical trial. One month following the third dose, seroprotection rates after Engerix-B and Recombivax were similar (99 and 98%, respectively). The geometric mean titre (GMT) was statistically significantly higher following vaccination with Engerix-B (3961 vs. 1001 mIU/ml; P=0.0001, Fisher's exact test). Most of the symptoms reported were mild or moderate in intensity and transient. There were no vaccine-related serious adverse events.

Immunogenicity of a recombinant Borrelia burgdorferi outer surface protein A vaccine against Lyme disease in children

BACKGROUND AND OBJECTIVE

A recombinant lipoprotein vaccine against Lyme disease, containing 30 microg of Borrelia burgdorferi outer surface protein A (OspA) with aluminum adjuvant, has been shown in a large US field trial of subjects >/=15 years of age to offer 76% efficacy against clinical Lyme disease after 3 injections given at 0, 1, and 12 months. Lyme disease is also an important problem in children; thus, OspA vaccine trials in children are needed. The purpose of this study was to investigate the safety and immunogenicity of 2 different doses of lipoprotein OspA with aluminum adjuvant vaccine in healthy children 5 to 15 years of age in a double-blind, randomized study.

STUDY DESIGN

In a double-blind study, 250 children from the Czech Republic were randomly assigned to receive 15 microg or 30 microg of OspA vaccine at 0, 1, and 2 months. Serum samples, obtained before vaccination and 1 month after the second and third doses, were analyzed for antiOspA antibody. Solicited and unsolicited symptoms were collected from diary cards.

RESULTS

Local pain at the injection site was reported by approximately 76% of the 250 children. Headaches (after 5% to 18% of the injections) and malaise (after 2% to 16% of the injections) were the most frequently reported general symptoms. Local and generalized symptoms were not different between the 15 microg and 30 microg groups, and all symptoms resolved within 4 days. Both doses were highly immunogenic, with the 30 microg dose eliciting higher antibody levels. Seroconversion occurred in 99% of the 250 children.

CONCLUSIONS

The OspA vaccine against Lyme disease was well tolerated and highly immunogenic in children.

Ganciclovir resistance and UL97 gene mutations in cytomegalovirus blood isolates from patients with AIDS treated with ganciclovir

BACKGROUND

Treatment of cytomegalovirus (CMV) diseases with protracted administration of ganciclovir can promote the development of resistant CMV that is associated with a poor response to therapy. It has been shown that the majority of ganciclovir-resistant CMV isolates carry mutations in the UL97 phosphotransferase gene.

OBJECTIVES

To evaluate the frequency of CMV resistance to ganciclovir in patients with AIDS treated with ganciclovir and to identify the UL97 gene mutations associated with ganciclovir resistance.

STUDY DESIGN

Analysis of CMV blood isolates obtained over 1 year from patients treated with ganciclovir. CMV susceptibility to ganciclovir was determined by an immediate early antigen plaque reduction assay; UL97 gene mutations were identified by restriction enzyme digest analysis and sequencing.

RESULTS

Twenty-nine patients were followed-up; 17 CMV blood isolates were obtained from 10 ganciclovir-experienced patients. Thirteen (76%) of these isolates, obtained from seven (24%) patients after a median treatment duration of 5.5 months, were resistant to ganciclovir. Five of the seven patients who had a ganciclovir-resistant CMV in blood showed retinitis progression. UL97 gene mutations were identified in nine CMV isolates at codons 460 (M --> V), 594 (A --> V and A --> T), and 595(L --> S). Three patients developed a ganciclovir-resistant virus after a ganciclovir treatment shorter than 60 days (28-58 days). In another patient, we observed that ganciclovir resistance persisted 4 months after discontinuation of ganciclovir therapy.

CONCLUSION

Our results indicate that ganciclovir resistance due to UL97 gene mutations is common in subjects with AIDS-related CMV diseases treated with ganciclovir. Detection of these mutations represents a tool for the management of patients with ganciclovir therapy.

[Acquired cytomegalovirus infections in immunocompetent adults: 116 cases]

OBJECTIVE

To analyse retrospectively the clinical, biological and epidemiological features of cytomegalovirus (CMV) infection in the immunocompetent host.

PATIENTS AND METHODS

A retrospective study was conducted in 116 cases of CMV infection (74 inpatients, 42 out-patients) collected from 1981 to 1997 in a university hospital. Diagnostic was established on serological criteria in all cases.

RESULTS

Fever was observed in all cases but one (mean duration: 21 days). The most frequent symptoms were headache (51%) and myalgia (46%). Splenomegaly was the most frequent sign (36%). Pulmonary interstitial opacities on chest x-ray were found in 8.5% of patients. Pulmonary (1 case) and neurological (2 cases) complications occurred. Concomitant HIV primary infection was observed in 2 patients. Mononucleosis and ALAT and LDH elevations were observed in 95%, 85% and 95% of cases respectively. Viremia was positive in 79% (30/38). pp65 antigenemia was useful to establish the diagnosis in 9 patients. Antibiotics were prescribed in 46% before diagnosis was established.

CONCLUSION

CMV infection in the immunocompetent host is a frequent and rarely complicated disease. pp65 antigenemia should be evaluated more in this setting. Most hospitalizations due to this affection could be avoided.

A tricarboxylic acid cycle intermediate regulating transcription of a chloroaromatic biodegradative pathway: fumarate-mediated repression of the clcABD operon

The ortho-cleavage pathways of catechol and 3-chlorocatechol are central catabolic pathways of Pseudomonas putida that convert aromatic and chloroaromatic compounds to tricarboxylic acid (TCA) cycle intermediates. They are encoded by the evolutionarily related catBCA and clcABD operons, respectively. Expression of the cat and clc operons requires the LysR-type transcriptional activators CatR and ClcR, respectively, and the inducer molecules cis,cis-muconate and 2-chloro-cis,cis-muconate, respectively. The regulation of the cat and clc promoters has been well studied, but the extent to which these operons are repressed by growth in TCA cycle intermediates has not been explored. We demonstrate by transcriptional fusion studies that the expression from the clc promoter is repressed when the cells are grown on succinate, citrate, or fumarate and that this repression is ClcR dependent and occurs at the transcriptional level. The presence of these organic acids did not affect the expression from the cat promoter. In vitro transcription assays demonstrate that the TCA cycle intermediate fumarate directly and specifically inhibits the formation of the clcA transcript. No such inhibition was observed when CatR was used as the activator on either the cat or clc template. Titration studies of fumarate and 2-chloromuconate show that the fumarate effect is concentration dependent and reversible, indicating that fumarate and 2-chloromuconate most probably compete for the same binding site on ClcR. This is an interesting example of the transcriptional regulation of a biodegradative pathway by the intracellular sensing of the state of the TCA cycle.