An unusual form of persistent polyclonal B lymphocytosis in an infant

We report a case of persistent polyclonal lymphocytosis in an infant. The circulating lymphocytes were of a small to medium size and a small proportion were larger and had lymphoplasmacytoid features. The presence of either an infectious or mutagenic agent was excluded. The polyclonal B-cell nature of the lymphocyte was demonstrated by immunological markers and confirmed by Southern blot analysis and by polymerase chain reaction targeting immunoglobulin genes. In contrast to the common form of polyclonal lymphocytosis, this case was not associated with HLA-DR7 and/or abnormalities of chromosome 3, p53 or Bcl2/IgH. Whether this lymphocytosis represents a premalignant or a benign condition remains uncertain, although there has been no progression to date.

A nonlinear biomathematical model for the study of intracranial aneurysms

The formation and rupture of aneurysms is a significant medical problem, but is not clearly understood. Most intracranial aneurysm are located in the circle of Willis. We consider a nonlinear mathematical model that simulates the blood flow inside the aneurysm, one of the relevant factors in the evolution of an aneurysm. Different techniques from nonlinear analysis are used in order to obtain, from the model, several consequences that would help to understand some medical aspects of aneurysms of the circle of Willis.

Sexual dimorphism in diethylstilbestrol-induced prolactin pituitary tumors in F344 rats

Female F344 rats treated chronically with diethylstilbestrol (DES) develop prolactin (PRL)-producing pituitary tumors. These tumors are larger in female than in male rats. To investigate gender differences in DES-induced pituitary tumor formation, we employed female and male rats and neonatally androgenized females, which received 100 microg of testosterone propionate (TP) after birth. At 3 months of age, all rats were deprived of their gonads and divided into control and DES-treated groups. Forty days after beginning treatment, control pituitary weight and serum PRL were similar in gonadectomized males (GDX), ovariectomized females (OVX) and androgenized-ovariectomized females (OVX + TP), but weight of DES-induced tumors was 2.5-fold higher and serum PRL 5.6-fold higher in OVX + DES than in GDX + DES or OXV + TP + DES (p<0.001). At the pituitary level, nuclear estrogen receptors (NE(2)R) amounted to >100 fmol/mg DNA in all rats receiving DES. However, NE(2)R were lower in OVX + DES (101.3+/-9.0 fmol/mg DNA) than in GDX + DES (174.6 +/-16.8; p<0.05) and in OXV + DES + TP (150.3+/-27.7; p<0.05). A similar profile was found for cytosolic progestin receptors. Using electron microscopy (EM), hyperplasia/hypertrophy of lactotropes was found in all DES-stimulated pituitaries. However, tumors of OVX + DES rats were enriched in hyperstimulated typical lactotropes, i.e., cells with high rate of hormonal synthesis, processing and secretion. Instead, tumors from GDX + DES and OVX + TP + DES rats were a mixture of typical and atypical lactotropes, i.e. a cell subpopulation with refractory secretory response and a few gonadotropes. In agreement with these data, immunoreactive pituitary PRL was lower in OVX + DES than in OVX + TP + DES and GDX + DES groups. Thus, differences in the sensitivity to DES, serum and tumor PRL, NE(2)R and progestin receptors between estrogenized female rats on one side and male and TP-androgenized females on the other, may by due in part to heterogeneity of cell populations. Our data further suggest that neonatal hypothalamic exposure to androgens, as in normal males or androgenized females with masculinization of hypothalamic centers, may condition the response to DES stimulation later in life.

Occurrence of Aspergillus section flavi and aflatoxin B1 in corn genotypes and corn meal in Argentina

A study has been carried out in Argentina on samples of corn genotypes from a breeding station as well as in commercially available corn meal. All samples were analyzed for fungal infection and aflatoxin B1. Mycological analysis of corn genotypes showed the presence of three principal genera of filamentous fungi Fusarium (100%), Penicillium (67%) and Aspergillus (60%). In the genus Fusarium three species were identified, F. moniliforme (42%), F. nygamai (56%) and F. proliferatum (1.8%). Eight species of Penicillium were identified, the predominant species isolated were P. minioluteum, P. funiculosum and P. variabile. In the genus ranked third in isolation frequency, two species were identified, A. flavus and A. parasiticus, the percentage of infection was 78% and 21%, respectively. Only one corn genotype was contaminated with aflatoxin B1 at a level of 5 ppb. The corn meal samples showed great differences in fungal contamination, the values ranging from 1 x 10(1) to 7 x 10(5) cfu g-1. Fusarium (68%), Aspergillus (35%) and Penicillium (21%) were the most frequent genera isolated. Among the genus, Aspergillus, A. parasiticus (38%) was the most frequent species isolated. All the samples of corn meal were negative to aflatoxin B1. These results indicate a low degree of human exposure to aflatoxins in Argentina through the ingestion of maize or corn meal.

Fatigue rating scales: an empirical comparison

BACKGROUND

There has been limited research comparing the efficacy of different fatigue rating scales for use with individuals with chronic fatigue syndrome (CFS). This investigation explored relationships between two commonly-used fatigue rating scales in CFS research, the Fatigue Scale and the Fatigue Severity Scale. Theoretically, these scales have been described as measuring different aspects of the fatigue construct. The Fatigue Scale was developed as a measure of the severity of specific fatigue-related symptoms, while the Fatigue Severity Scale was designed to assess functional outcomes related to fatigue.

METHODS

Associations of these scales with the eight definitional symptoms of CFS and with eight domains of functional disability were examined separately in: (1) an overall sample of individuals with a wide range of fatigue severity and symptomatology; (2) a subsample of individuals with CFS-like symptomatology, and, (3) a subsample of healthy controls.

RESULTS

Findings revealed that both scales are appropriate and useful measures of fatigue-related symptomatology and disability within a general population of individuals with varying levels of fatigue. However, the Fatigue Severity Scale appears to represent a more accurate and comprehensive measure of fatigue-related severity, symptomatology, and functional disability for individuals with CFS-like symptomatology.

Heart rate responses to a muscarinic agonist in rats with experimentally induced acute and subacute chagasic myocarditis

We administered arecoline to rats, with experimentally induced chagasic myocarditis, in order to study the sinus node sensitivity to a muscarinic agonist. Sixteen month old rats were inoculated with 200,000 T. cruzi parasites ("Y" strain). Between days 18 and 21 (acute stage), 8 infected rats and 8 age-matched controls received intravenous arecoline as a bolus injection at the following doses: 5. 0, 10.0, 20.0, 40.0, and 80.0 microg/kg. Heart rate was recorded before, during and after each dose of arecoline. The remaining 8 infected animals and 8 controls were subjected to the same experimental procedure during the subacute stage, i.e., days 60 to 70 after inoculation. The baseline heart rate, of the animals studied during the acute stage (349 +/- 68 bpm, mean +/- SD), was higher than that of the controls (250 +/- 50 bpm, p < 0.005). The heart rate changes were expressed as percentage changes over baseline values. A dose-response curve was constructed for each group of animals. Log scales were used to plot the systematically doubled doses of arecoline and the induced-heart rate changes. The slope of the regression line for the acutely infected animals (r = - 0.99, b =1.78) was not different from that for the control animals (r = - 0.97, b = 1.61). The infected animals studied during the subacute stage (r = - 0.99, b = 1.81) were also not different from the age-matched controls (r = - 0.99, b = 1.26, NS). Consequently, our results show no pharmacological evidence of postjunctional hypersensitivity to the muscarinic agonist arecoline. Therefore, these results indirectly suggest that the postganglionic parasympathetic innervation, of the sinus node of rats with autopsy proved chagasic myocarditis, is not irreversibly damaged by Trypanosoma cruzi.

Antimicrobial treatment failures in patients with community-acquired pneumonia: causes and prognostic implications

The aim of the study was to determine the causes and prognostic implications of antimicrobial treatment failures in patients with nonresponding and progressive life-threatening, community-acquired pneumonia. Forty-nine patients hospitalized with a presumptive diagnosis of community-acquired pneumonia during a 16-mo period, failure to respond to antimicrobial treatment, and documented repeated microbial investigation >/= 72 h after initiation of in-hospital antimicrobial treatment were recorded. A definite etiology of treatment failure could be established in 32 of 49 (65%) patients, and nine additional patients (18%) had a probable etiology. Treatment failures were mainly infectious in origin and included primary, persistent, and nosocomial infections (n = 10 [19%], 13 [24%], and 11 [20%] of causes, respectively). Definite but not probable persistent infections were mostly due to microbial resistance to the administered initial empiric antimicrobial treatment. Nosocomial infections were particularly frequent in patients with progressive pneumonia. Definite persistent infections and nosocomial infections had the highest associated mortality rates (75 and 88%, respectively). Nosocomial pneumonia was the only cause of treatment failure independently associated with death in multivariate analysis (RR, 16.7; 95% CI, 1.4 to 194.9; p = 0.03). We conclude that the detection of microbial resistance and the diagnosis of nosocomial pneumonia are the two major challenges in hospitalized patients with community-acquired pneumonia who do not respond to initial antimicrobial treatment. In order to establish these potentially life-threatening etiologies, a regular microbial reinvestigation seems mandatory for all patients presenting with antimicrobial treatment failures.

Noninvasive versus invasive microbial investigation in ventilator-associated pneumonia: evaluation of outcome

Noninvasive and invasive diagnostic techniques have been shown to achieve comparable performances in the evaluation of suspected ventilator-associated pneumonia (VAP). We studied the impact of both approaches on outcome in a prospective, open, and randomized study in three intensive care units (ICUs) of a 1,000-bed tertiary care university hospital. Patients with suspected VAP were randomly assigned to noninvasive (Group 1) versus invasive (Group 2) investigation (tracheobronchial aspirates [TBAS] versus bronchoscopically retrieved protected specimen brush [PSB] and bronchoalveolar lavage [BAL]. Samples were cultured quantitatively, and BAL fluid (BALF) was examined for intracellular organisms (ICO) additionally. Initial empiric antimicrobial treatment was administered following the guidelines of the American Thoracic Society (ATS) and adjusted according to culture results (and ICO counts in Group 2). Outcome variables included length of ICU stay and mechanical ventilation as well as mortality. Overall, 76 patients (39 noninvasive, 37 invasive) were investigated. VAP was microbiologically confirmed in 23 of 39 (59%) and 23 of 37 (62%) (p = 0.78). There were no differences with regard to the frequencies of community-acquired and potentially drug-resistant microorganisms (PDRM). Antimicrobial treatment was changed in seven patients (18%) of Group 1 and 10 patients (27%) of Group 2 because of etiologic findings (including five of 17 with ICO = 2% (p = not significant [NS]). Length of ICU stay and mechanical ventilation were also not significantly different in both groups. Crude 30-d mortality was 31 of 76 (41%), and 18 of 39 (46%) in Group 1 and 14 of 37 (38%) in Group 2 (p = 0.46). Adjusted mortality was 16% versus 11% (p = 0.53), and mortality of microbiologically confirmed pneumonia 10 of 23 (44%) in both groups (p = 1.0). We conclude that the outcome of VAP was not influenced by the techniques used for microbial investigation.

Molecular genetic analysis of severe protein C deficiency

Severe protein C deficiency is a rare, early onset, venous thrombotic condition that is inherited as an autosomal recessive trait. The protein C (PROC) genes of nine unrelated individuals with severe protein C deficiency were sequenced yielding a total of 13 different lesions. Eight of these were novel, including a gross gene deletion, three missense mutations, two micro-deletions, a splicing mutation and a single base-pair substitution in the HNF-3 binding site in the PROC gene promoter. Evidence for the pathogenicity of the mutations detected was obtained by molecular modelling, in vitro splicing assay and reporter gene assay. Neither the plasma protein C activity level nor the nature of the PROC gene lesions detected were found to be a good prognostic indicator of the age of onset or clinical severity of thrombotic symptoms. Other factors may thus complicate the relationship between genotype and clinical phenotype. Indeed, in two patients, the inheritance of either one or two Factor V Leiden alleles in addition to two PROC gene lesions could have served to precipitate the thrombotic events. No association was however apparent between clinical severity and the possession of a particular promoter polymorphism genotype. Despite the absence of a clear genotype-phenotype relationship, the molecular genetic analysis of the severe recessive form of protein C deficiency potentiates both the counselling of affected families and the provision of antenatal exclusion diagnosis.

Plasma thrombopoietin level after liver transplantation: relationship to cold ischemia time and coagulation parameters

OBJECTIVE

To determine the relation between thrombopoietin (Tpo) levels following orthotopic liver transplantation (OLT), cold ischemia time and postoperative peripheral blood platelet count and prothrombin activity.

DESIGN

Prospective clinical study.

SETTING

Intensive care unit.

PATIENTS

Fourteen patients with uncomplicated postoperative course after OLT.

MEASUREMENTS AND RESULTS

Plasma Tpo, as quantified by enzyme immunoassay, rose significantly from 194.9 +/- 45.7 pg/ml on day 1 after OLT to a peak value of 500.7 +/- 94.1 pg/ml on day 5 while platelet count was below normal values. Then the platelet count increased and reached normal values while Tpo decreased to normal. The rise of Tpo levels was associated with normalization of prothrombin time but peak Tpo concentrations were in inverse correlation with cold ischemia times.

CONCLUSION

The extent of production of Tpo in the liver graft following OLT is affected by cold ischemia time. This observation may be applicable in the prevention of bleeding complications associated with postoperative thrombocytopenia.

Method for intraoperative positioning of the nipple-areola complex in vertical scar reduction mammaplasty

The desired shape and position of the nipple-areola complex may be difficult to achieve in vertical scar reduction mammaplasty when using the standard technique of preoperative marking of the so-called mosque-shaped areolar pattern of excision. We describe our modified approach of intraoperative final positioning of the nipple-areola complex by hiding the nipple-areola complex behind the closed vertical incision. Individual positioning at the final part of the operation allows for more predictable results and also for a calculated lower positioning, which enables balance of the potential bottoming-out of the breast, particularly in previously large ptotic breasts. We believe that this modification helps to further improve the results of vertical scar reduction mammaplasty by adding more possibilities for shaping and "last-minute" modifications intraoperatively.

Unrelated donor bone marrow transplantation as treatment for chronic myeloid leukemia: the Spanish experience. The Chronic Myeloid Leukemia Subcommittee of the GETH. Grupo Español de Trasplante Hemopoyético

BACKGROUND AND OBJECTIVE

To analyze the results of unrelated bone marrow transplantation (UDBMT) as treatment for chronic myeloid leukemia (CML) in Spain.

DESIGN AND METHODS

Eighty-seven consecutive UDBMT performed in 9 centers between October 1989 and February 1998 were evaluated. This represents more than 95% of UDBMT for CML performed in adult transplant centers in Spain during this period. The patients' median age was 31.5 years (range, 12-49). The median interval from CML diagnosis to UDBMT was 30 months (range, 3-160). Seventy-nine percent of transplants were performed during the first chronic phase (1CP).

RESULTS

Actuarial probability of survival and disease-free survival at 4 years for the whole series was 24% (95% confidence interval [CI]: 14%-34%) and 20% (CI: 10%-30%), respectively. The cumulative incidence of relapse and transplant-related mortality (TRM) was 7% (CI: 4%-10%) and 71% (CI: 60%-82%), respectively. The main causes of death were graft failure (n=7), infection (n=23), and graft-versus-host disease (GvHD) (n=25). The actuarial probability of acute GvHD grade II-IV and grade III-IV was 56% (CI:46%-66%) and 36% (CI: 26%-36%), respectively. The cumulative incidence of extensive chronic GvHD was 18% (CI: 9%-27%). Univariate analyses showed that the pre-transplant factor with the highest influence on survival was disease status at transplant (30% in 1CP vs. 0% in advanced phases; p=0.0001). Other pre-transplant factors influencing survival among patients in 1CP were: patient's age (older than 30 years 11% vs. 48%), interval diagnosis-transplantation (longer than 2 years 17% vs. 55%), donor type (HLA, B, DRB1 identical 32% vs. 25%), CMV serologic status (donor and recipient negative 63% vs. 24%), year of transplantation (before 1995 19% vs. 40%), and conditioning regimen (cyclophosphamide plus total body radiation 40% vs. 16%). The main risk factors had a cumulative effect on survival. Thus, probability of survival ranged from 66% (CI: 39%-93%) in patients in 1CP, under 40 years of age, transplanted from an HLA, A, B, DRB1 identical donor during the first two years after diagnosis, to 0% in those with three or more risk factors.

INTERPRETATION AND CONCLUSIONS

This experience shows that UDBMT used to have a high TRM that has progressively decreased along the years. At the present time, the results are encouraging, particularly when UDBMT is performed under favorable conditions.

Molecular analysis of lineage-specific chimerism and minimal residual disease by RT-PCR of p210(BCR-ABL) and p190(BCR-ABL) after allogeneic bone marrow transplantation for chronic myeloid leukemia: increasing mixed myeloid chimerism and p190(BCR-ABL) detection precede cytogenetic relapse

We studied lineage-specific chimerism and minimal residual disease (MRD) in sequential posttransplant samples from 55 patients who underwent unmanipulated (n = 44) or partially T-cell-depleted (n = 11) allogeneic bone marrow transplantation (BMT) for chronic myeloid leukemia (CML). Chimerism was assessed by polymerase chain reaction (VNTR [variable number of tandem repeats]-PCR) analysis in highly purified CD19+, CD3+, CD15+, and CD56+ cell fractions, whereas MRD was investigated in whole blood by reverse transcriptase-PCR (RT-PCR) of both p210(BCR-ABL) and p190(BCR-ABL) hybrid transcripts. Of 55 patients, 14 (including 6 T-cell-depleted patients) had cytogenetic relapse at 5-80 months and progressed to hematologic relapse, while 41 patients remained in prolonged cytogenetic remission 12-107 months post-BMT. Before leukemia recurrence, patients in the relapse group showed a consistent evolution pattern sequentially featured by persistent p210(BCR-ABL) positivity, increasing mixed chimerism (MC) in myeloid cells, p190(BCR-ABL) positivity, and, finally, cytogenetic relapse. Myeloid MC preceded cytogenetic relapse by 2-12 months, whereas p190(BCR/ABL) was detected 1-6 months prior to cytogenetic relapse in 11 patients and concomitant with cytogenetic relapse in 3 patients. In the remission group, all patients invariably tested negative for p190(BCR-ABL); 10 patients tested positive for p210(BCR-ABL) at variable time-points but showed persistent full donor chimerism (DC), whereas 31 patients tested p210(BCR-ABL) negative and displayed full DC or transient MC due to the persistence of recipient T cells. Two patients in the relapse group were successfully reinduced into molecular remission with donor lymphocyte infusion. Sequential molecular analysis after such treatment showed the inverse pattern to that observed prior to relapse, ie, progressive disappearance of p190(BCR-ABL) transcripts, conversion of myeloid chimerism to donor type, and, finally, p210(BCR-ABL) negativity. We conclude that lineage-specific chimerism and p190(BCR-ABL) messenger RNA (mRNA) analyses contribute a better characterization of CML evolution after BMT and enable early identification of patients at the highest risk of relapse. (Blood. 2000;95:2659-2665)

The vasectomized testis

We have performed a qualitative study on effects of vasectomy on the testicular structure. Vasectomy performed with the traditional technique changes testicular structure. At first, the injuries are slight and restricted, but gradually, and in a time-dependent manner, become more severe and extensive. Ultrastructure studies indicate that the spermatogonia and Sertoli's cells are the most resistant to vasectomy, and are even observed in some regenerating testes lacking a complete germinal epithelium. Morphometric studies revealed a decrease in epithelial depth, an increase in the thickness of the basement membrane and in surface of the interstitial space, all significant (P < 0.01) with respect to the control. However, the percentage of the interstitial tissue occupied by cells, did not show any significant difference. We propose that the increase of intraluminal pressure is the essential factor that provokes testicular atrophy.

[Localization of lung nodules with CT-guided hookwire before videothoracoscopic surgery]

PURPOSE

To localize peripheral lung nodules under CT guidance using hookwires, prior to video-assisted thoracic surgery (VATS).

PATIENTS AND METHODS

Twenty-two pulmonary nodules were localized with a hookwire under CT guidance. The visceral pleura was stained with methylene blue. VATS was performed thereafter.

RESULTS

All nodules were successfully localized and resected without significant complications.

CONCLUSIONS

In select cases, localization of pulmonary nodules with hook wire and methylene blue allows the thoracoscopic resection of unaccessible lesions.

Detection of telomerase activity in human carcinomas using a trap-ELISA method: correlation with hTR and hTERT expression

We have evaluated telomerase activity in a tumour population of 65 human cancers by using a TRAP-based method, in which detection is performed by an enzyme immunoassay (ELISA). We have corroborated that sensitivity and specificity of this new procedure can be considered similar to that of classical TRAP method, having the advantage of a rapid and reproducible analysis of large pools of samples. Thus, telomerase activity was detected in 83% of the tumours included in our population. Moreover, we found a significant association between enzyme activity and both hTR and hTERT expression (P=0.004 and P=0.04, respectively).

Treatment of gram-positive nosocomial pneumonia. Prospective randomized comparison of quinupristin/dalfopristin versus vancomycin. Nosocomial Pneumonia Group

Nosocomial pneumonia is a frequent complication in hospitalized patients. Gram-positive pathogens, particularly Staphylococcus aureus, are responsible for the increasing frequency of nosocomial pneumonia. To evaluate the efficacy and safety of intravenous quinupristin/dalfopristin (Synercid) in the treatment of nosocomial pneumonia caused by gram-positive pathogens we conducted a prospective, randomized, open-label, international, multicenter, comparative clinical trial. Two hundred ninety-eight patients with nosocomial pneumonia were enrolled in 74 active centers in five countries: a subgroup of 171 (87 quinupristin/dalfopristin-treated and 84 vancomycin-treated patients) were evaluable for the major efficacy end points. One hundred fifty received 7.5 mg/kg of quinupristin/dalfopristin every 8 h; 148 patients received 1 g of vancomycin every 12 h. Aztreonam at a dose of 2 g every 8 h could be administered in both groups for coverage of gram-negative organisms, and tobramycin was added for coverage against Pseudomonas aeruginosa. The primary efficacy end point was the clinical response between the seventh and the thirteenth day after the end of treatment in clinically evaluable patients with documented causative pathogen(s) at baseline (bacteriologically evaluable population). Therapy was clinically successful (cure or improvement) in 49 (56.3%) of patients receiving quinupristin/dalfopristin and 49 (58.3%) patients receiving vancomycin (difference, -2.0% [95% CI, -16.8% to 12.8%]) in the bacteriologically evaluable population. Equivalent clinical success rates were also observed in the all-treated population (n = 298), and in the bacteriologically evaluable patients intubated in baseline (39/72 [54%] compared with 36/67 [54%]). The by-pathogen bacteriologic response was similar in both treatment groups, with equivalent clinical success rates for Streptococcus pneumoniae, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus. Adverse events (venous and nonvenous) were equally distributed between groups; 15.3% of quinupristin/dalfopristin patients and 9.5% of vancomycin patients discontinued therapy because of an adverse clinical event. In this study quinupristin/dalfopristin was shown to be equivalent to vancomycin in the treatment of nosocomial pneumonia caused by gram-positive pathogens. Quinupristin/dalfopristin merits further evaluation for the treatment of nosocomial pneumonia caused by methicillin-resistant S. aureus.

Evaluation of antimicrobial treatment in mechanically ventilated patients with severe chronic obstructive pulmonary disease exacerbations

OBJECTIVE

To study microbial and susceptibility patterns and antimicrobial treatment responses in patients with severe, acute exacerbations of chronic obstructive pulmonary disease requiring mechanical ventilation.

DESIGN

Microbial investigation using tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage, as well as paired serologies. Evaluation of antimicrobial treatment by results of the initial investigation, susceptibility testing, and a repeated microbial investigation (tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage) after 72 hrs.

SETTING

A respiratory intensive care unit of a 1,000-bed teaching hospital.

PATIENTS

Fifty severely exacerbated and mechanically ventilated patients with chronic obstructive pulmonary disease.

INTERVENTIONS

Initial empirical antimicrobial treatment according to clinical judgment.

MEASUREMENTS AND MAIN RESULTS

Overall, 36 of 50 patients (72%) had evidence of a microbial origin. Community-acquired endogenous pathogens were present in 70% of patients, and Gram-negative enteric bacilli and Pseudomonas/Stenotrophomonas species were present in 30%. All five isolates of Streptococcus pneumoniae were resistant to penicillin (three intermediately and two highly), and three were resistant to multiple antibiotics. Pseudomonas species revealed multiresistance in four of nine isolates (44%), and Stenotrophomonas maltophilia revealed multiresistance in one of two isolates. Antimicrobial treatment was modified according to diagnostic results in 11 of 31 patients (36%) with potentially pathogenic microorganisms. In patients who underwent a repeat investigation after 72 hrs, 24% of the initially present and potentially pathogenic microorganisms persisted. Inappropriate initial antimicrobial therapy was associated significantly with bacterial persistence (p < .002).

CONCLUSIONS

Considering the diversity of microbial pathogens and the resistance rates especially to S. pneumoniae in this patient population, antimicrobial treatment should be based on the constant study of local microbial and susceptibility patterns along with routine microbial investigation of the individual patient.

Myeloid mixed chimerism is associated with relapse in bcr-abl positive patients after unmanipulated allogeneic bone marrow transplantation for chronic myelogenous leukemia

BACKGROUND AND OBJECTIVE

Although bcr-abl polymerase chain reaction (PCR) positivity after bone marrow transplantation (BMT) for chronic myelogenous leukemia (CML) is significantly related to relapse, the predictive value of the assay is not very high and therefore most investigators consider that qualitative RT-PCR data alone are too imprecise to enable clinical decisions to be taken in individual cases. To define the clinical outcome of bcr-abl positive patients after unmanipulated BMT better, we sought the origin of hematopoiesis and traced its evolution over time.

DESIGN AND METHODS

Forty-nine patients received allogeneic BMT for CML (39 in chronic phase and 10 in accelerated phase/blast crisis). Median follow-up was 61 months (range 4-92). mRNA and DNA were used to assess bcr-abl and chimerism status respectively. Quantitative VNTR-PCR on total cells and lymphoid or myeloid population allowed us to assign and measure the origin of hematopoiesis.

RESULTS

Both bcr-abl positivity and the presence of mixed chimerism (MC) were significantly associated with relapse (p = 0.0009 and p < 0.0001 respectively). Relapse was observed in one of 39 patients with complete donor chimerism and in 6 of 9 patients with MC. These six cases showed increasing levels of host hemopoiesis and bcr-abl positivity in the CD15-positive population prior to relapse. The other three cases had decreasing or stable low-level MC which was restricted to the T-cells as well as bcr-abl negativity.

INTERPRETATION AND CONCLUSIONS

Whereas the simple detection of bcr-abl fails to identify patients who will relapse with certainty, the assessment of MC by VNTR-PCR does identify patients headed to relapse. Confirmation of myeloid involvement and increasing levels over time further elucidates the clinical outcome of bcr-abl positive patients after BMT.

Etiology and microbial patterns of pulmonary infiltrates in patients with orthotopic liver transplantation

STUDY OBJECTIVE

To evaluate the etiology and microbial patterns of pulmonary infiltrates in liver transplant patients using a bronchoscopic diagnostic approach and the impact of diagnostic results on antimicrobial treatment decisions.

DESIGN

A prospective cohort study.

SETTING

A 1,000-bed tertiary-care university hospital.

PATIENTS AND METHODS

Fifty consecutive liver transplant patients with 60 episodes of pulmonary infiltrates (33 episodes during mechanical ventilation) were studied using flexible bronchoscopy with protected specimen brush (PSB) and BAL.

RESULTS

A definite infectious etiology was confirmed in 29 episodes (48%). Eighteen episodes corresponded to probable pneumonia (30%), 10 episodes had noninfectious etiologies (17%), and 3 remained undetermined (5%). Opportunistic infections were the most frequent etiology (16/29, 55%, including 1 mixed etiology). Bacterial infections (mainly Gram-negative) accounted for 14 of 29 episodes (48%), including 1 of mixed etiology. The majority of bacterial pneumonia episodes (n = 10, 71%) occurred in period 1 (1 to 28 days posttransplant) during mechanical ventilation, whereas opportunistic episodes were predominant in periods 2 and 3 (29 to 180 days and > 180 days posttransplant, respectively; n = 14, 82%). Microbial treatment was changed according to diagnostic results in 21 episodes (35%).

CONCLUSIONS

Microbial patterns in liver transplant patients with pulmonary infiltrates corresponded to nosocomial, mainly Gram-negative bacterial pneumonia in period 1, and to opportunistic infections in period 2 and, to a lesser extent, period 3. A comprehensive diagnostic evaluation including PSB and BAL fluid examination frequently guided specific antimicrobial therapy.