Genetic adaptation of Pseudomonas aeruginosa to the airways of cystic fibrosis patients is catalyzed by hypermutation

In previous work (E. E. Smith, D. G. Buckley, Z. Wu, C. Saenphimmachack, L. R. Hoffman, D. A. D'Argenio, S. I. Miller, B. W. Ramsey, D. P. Speert, S. M. Moskowitz, J. L. Burns, R. Kaul, and M. V. Olson, Proc. Natl. Acad. Sci. USA 103:8487-8492, 2006) it was shown that Pseudomonas aeruginosa undergoes intense genetic adaptation during chronic respiratory infection (CRI) in cystic fibrosis (CF) patients. We used the same collection of isolates to explore the role of hypermutation in this process, since one of the hallmarks of CRI is the high prevalence of DNA mismatch repair (MMR) system-deficient mutator strains. The presence of mutations in 34 genes (many of them positively linked to adaptation in CF patients) in the study collection of 90 P. aeruginosa isolates obtained longitudinally from 29 CF patients was not homogeneous; on the contrary, mutations were significantly concentrated in the mutator lineages, which represented 17% of the isolates (87% MMR deficient). While sequential nonmutator lineages acquired a median of only 0.25 mutation per year of infection, mutator lineages accumulated more than 3 mutations per year. On the whole-genome scale, data for the first fully sequenced late CF isolate, which was also shown to be an MMR-deficient mutator, also support these findings. Moreover, for the first time the predicted amplification of mutator populations due to hitchhiking with adaptive mutations in the course of natural human infections is clearly documented. Interestingly, increased accumulation of mutations in mutator lineages was not a consequence of overrepresentation of mutations in genes involved in antimicrobial resistance, the only adaptive trait linked so far to hypermutation in CF patients, demonstrating that hypermutation also plays a major role in P. aeruginosa genome evolution and adaptation during CRI.

Humoral and cellular monitoring to predict the development of infection in Crohn's disease patients beginning treatment with infliximab

Although severe infectious complications are rare, it is important to properly screen patients for predisposing conditions before beginning treatment with infliximab. We assessed immunity markers that might provide prognostic value for the development of infection in Crohn's disease patients after treatment with infliximab. In a prospective study, 34 fistulizing Crohn's disease patients (mean age 37 years) were studied. Patients were scheduled to receive three infusions of infliximab (5 mg/kg) at weeks 0, 2, and 6. Immunologic studies: Serum immunoglobulin (IgG, IgA, IgM), IgG-subclasses, and complement (C3, C4, factor B) determined by nephelometry; CD3+, CD3+CD4+, CD3+CD8+, CD19+, and CD56+CD3- lymphocyte subsets performed by flow cytometry. During a mean follow-up of 56 months, 1 patient had disseminated tuberculosis and 2 patients had severe bacterial infections. The presence of infection was associated with significantly higher IgM (246 vs. 121 mg/dL; Mann-Whitney test, P = 0.01), lower C3 (64 vs. 118, P = 0.02), lower C4 concentrations (12 vs. 25, P = 0.02), and with decreased levels of CD19 B cells (47 vs. 290, P = 0.03) in the baseline study. Further prospective studies in a larger number of patients are suggested to examine whether early monitoring of immunocompetence might help to identify the risk of infection in patients treated with infliximab.

Sex-based differences in T lymphocyte responses in HIV-1-seropositive individuals

Sex-based differences in the levels of human immunodeficiency virus 1 (HIV-1) RNA in plasma could be associated with differences in the strength of HIV-1-specific CD8(+) T cell responses. CD8(+) effector responses in 18 men and 15 women were measured 0-2 years (time A) and 5-7 years (time B) after seroconversion. CD8(+) effector responses were seen in 7 (39%) of 18 men and 2 (13%) of 15 women at time A (P=.13) and in 12 (67%) of 18 men and 10 (67%) of 15 women at time B (P=.99). At time B, the strength of CD8(+) effector responses correlated with the number of CD4(+) lymphocytes in women ( rho =-0.68; P=.005) but not in men ( rho =-0.14; P=.58). The level of HIV-1 RNA was not associated with the strength of CD8(+) effector responses according to sex, but there was a sex-based difference in the correlation between the strength of CD8(+) effector response and the number of CD4(+) lymphocytes.

The PREMIER study: A multicenter, randomized, double-blind clinical trial of combination therapy with adalimumab plus methotrexate versus methotrexate alone or adalimumab alone in patients with early, aggressive rheumatoid arthritis who had not had previous methotrexate treatment

OBJECTIVE

To compare the efficacy and safety of adalimumab plus methotrexate (MTX) versus MTX monotherapy or adalimumab monotherapy in patients with early, aggressive rheumatoid arthritis (RA) who had not previously received MTX treatment.

METHODS

This was a 2-year, multicenter, double-blind, active comparator-controlled study of 799 RA patients with active disease of < 3 years' duration who had never been treated with MTX. Treatments included adalimumab 40 mg subcutaneously every other week plus oral MTX, adalimumab 40 mg subcutaneously every other week, or weekly oral MTX. Co-primary end points at year 1 were American College of Rheumatology 50% improvement (ACR50) and mean change from baseline in the modified total Sharp score.

RESULTS

Combination therapy was superior to both MTX and adalimumab monotherapy in all outcomes measured. At year 1, more patients receiving combination therapy exhibited an ACR50 response (62%) than did patients who received MTX or adalimumab monotherapy (46% and 41%, respectively; both P < 0.001). Similar superiority of combination therapy was seen in ACR20, ACR70, and ACR90 response rates at 1 and 2 years. There was significantly less radiographic progression (P < or = 0.002) among patients in the combination treatment arm at both year 1 and year 2 (1.3 and 1.9 Sharp units, respectively) than in patients in the MTX arm (5.7 and 10.4 Sharp units) or the adalimumab arm (3.0 and 5.5 Sharp units). After 2 years of treatment, 49% of patients receiving combination therapy exhibited disease remission (28-joint Disease Activity Score <2.6), and 49% exhibited a major clinical response (ACR70 response for at least 6 continuous months), rates approximately twice those found among patients receiving either monotherapy. The adverse event profiles were comparable in all 3 groups.

CONCLUSION

In this population of patients with early, aggressive RA, combination therapy with adalimumab plus MTX was significantly superior to either MTX alone or adalimumab alone in improving signs and symptoms of disease, inhibiting radiographic progression, and effecting clinical remission.

Greater effect of highly active antiretroviral therapy on survival in people aged > or =50 years compared with younger people in an urban observational cohort

Although human immunodeficiency virus-infected people aged > or =50 years have a blunted CD4 cell recovery when receiving highly active antiretroviral therapy (HAART), there are few data on mortality. Mortality rates were studied for 253 individuals aged > or =50 years and a younger group of 535 people in a retrospective cohort; for untreated persons in each age group, the proportions surviving at 3 years were 83% and 70% (P<.01), respectively. No significant difference in the survival rate was found between the older (83%) and younger (89%) patients who received HAART (P=.29). The hazard ratio for death in the older untreated group was 2.4 (95% confidence interval [CI], 1.4-3.9) when exposed to HAART. However, compared with older untreated patients, the hazard ratio for death decreased to 0.28 (95% CI, 0.15-0.52) for treated older adults. The effect of HAART substantially improves the survival rate for older individuals and supports the importance of treatment in this group.

PICK1 targets activated protein kinase Calpha to AMPA receptor clusters in spines of hippocampal neurons and reduces surface levels of the AMPA-type glutamate receptor subunit 2

The PICK1 protein interacts in neurons with the AMPA-type glutamate receptor subunit 2 (GluR2) and with several other membrane receptors via its single PDZ domain. We show that PICK1 also binds in neurons and in heterologous cells to protein kinase Calpha (PKCalpha) and that the interaction is highly dependent on the activation of the kinase. The formation of PICK1-PKCalpha complexes is strongly induced by TPA, and PICK1-PKCalpha complexes are cotargeted with PICK1-GluR2 complexes to spines, where GluR2 is found to be phosphorylated by PKC on serine 880. PICK1 also reduces the plasma membrane levels of the GluR2 subunit, consistent with a targeting function of PICK1 and a PKC-facilitated release of GluR2 from the synaptic anchoring proteins ABP and GRIP. This work indicates that PICK1 functions as a targeting and transport protein that directs the activated form of PKCalpha to GluR2 in spines, leading to the activity-dependent release of GluR2 from synaptic anchor proteins and the PICK1-dependent transport of GluR2 from the synaptic membrane.

Synthesis, structure, luminescence, and theoretical studies of tetranuclear gold clusters with phosphinocarborane ligands

Treatment of the tetranuclear gold cluster [Au4((PPh2)2C2B9H10)2(AsPh3)2] (1), which contains the nido-carborane-diphosphine [7,8-(PPh2)2C2B9H10]-, with various tertiary phosphines leads to derivatives [Au4((PPh2)2C2B9H10)2-(PR3)2] (PR3 = PPh3 (2), P(4-MeC6H4)3 (3), P(4-OMeC6H4)3 (4)). The X-ray crystal structure of complex 4 shows a tetrahedral framework of gold atoms, two of which are chelated by the diphosphine, and two are coordinated to one monophosphine ligand each. These compounds are very stable and are obtained in high yield. MP2 calculations suggest that the two types of chemically nonequivalent gold atoms can be formally assigned as Au(I) (those attached to the arsines or phosphines) and Au(0) (those bonded to the anionic diphosphine) and emphasize the role of correlation in the gold-gold interactions. The compounds are luminescent. The emission is assigned to a gold-centered spin-forbidden transition; the assignment of the oxidation state of the gold centers on this basis leads to results coincident with those obtained by theoretical calculations.

Mutagenesis reveals a role for ABP/GRIP binding to GluR2 in synaptic surface accumulation of the AMPA receptor

We studied the role of PDZ proteins GRIP, ABP, and PICK1 in GluR2 AMPA receptor trafficking. An epitope-tagged MycGluR2 subunit, when expressed in hippocampal cultured neurons, was specifically targeted to the synaptic surface. With the mutant MycGluR2delta1-10, which lacks the PDZ binding site, the overall dendritic intracellular transport and the synaptic surface targeting were not affected. However, over time, Myc-GluR2delta1-10 accumulated at synapses significantly less than MycGluR2. Notably, a single residue substitution, S880A, which blocks binding to ABP/GRIP but not to PICK1, reduced synaptic accumulation to the same extent as the PDZ site truncation. We conclude that the association of GluR2 with ABP and/or GRIP but not PICK1 is essential for maintaining the synaptic surface accumulation of the receptor, possibly by limiting its endocytotic rate.

Aortic valve replacement in patients with aortic stenosis and severe left ventricular dysfunction

BACKGROUND

The outcome of aortic valve replacement for severe aortic stenosis is worse in patients with impaired left ventricular function. Such dysfunction in aortic stenosis may be reversible if caused by afterload mismatch, but not if it is caused by superimposed myocardial infarction.

METHODS

From our echocardiography database, 55 patients with severe aortic stenosis (valve area < or =0.75 cm2) and ejection fractions of 30% or lower who subsequently underwent aortic valve replacement were included. The operative mortality and clinical follow-up were detailed.

RESULTS

There were 10 perioperative deaths (operative mortality, 18%). Twenty (36%) of the 55 patients had a prior myocardial infarction. In the 35 patients without prior myocardial infarction, there was only 1 death (3%). In contrast, 9 of 20 patients with prior myocardial infarction died (mortality rate, 45%; P< or =.001). The factors significantly associated with perioperative death on univariate analysis (functional class, mean aortic gradient, and prior myocardial infarction) were entered into a model for stepwise logistic regression. This multivariate analysis showed that only prior myocardial infarction was independently associated with perioperative death (odds ratio, 14.9; 95% confidence interval, 2.4-92.1; P = .004).

CONCLUSIONS

The risk of aortic valve replacement in patients with severe aortic stenosis and severely reduced left ventricular systolic function is extremely high if the patients have had a prior myocardial infarction. This information should be factored into the risk-benefit analysis that is done preoperatively for these patients, and it may preclude operation for some.

Molecular tracking of coagulase-negative staphylococcal isolates from catheter-related infections

Three molecular typing methods (pulsed-field electrophoresis, localization of the mecA gene, and probing the vicinity of mec) have been used for the characterization of 40 catheter-related isolates of coagulase-negative staphylococci (CNS) in 14 patients admitted to the same hospital. The 40 isolates yielded 14 different SmaI banding patterns and corresponding unique localizations of mecA, each associated with a unique ClaI mecA polymorph. In 6 of the 14 patients the contaminated skin at the catheter entry site was the source of 4 local infections and 2 cases of bacteremia. A contaminated hub was the origin of 2 local infections and 4 cases of bacteremia in 6 more patients. The remaining 2 patients had positive cultures from both skin and catheter hub. In each bacteremic patient, the CNS recovered from catheter-related sites (tip, skin, and/or hub) and the CNS recovered from blood were identical, but each of these matching isolates was unique to the particular patients, indicating a low rate of cross-infection from patient to patient. Although classical methods for typing CNS (e.g., biotype and antibiotype) are readily available for most hospital laboratories, they have limitations concerning reproducibility and discriminatory power. Molecular epidemiologic techniques can provide powerful support to traditional techniques in determining the etiologic role of CNS in the disease process.

Analysis of the discontinuation of protease inhibitor therapy in routine clinical practice

We evaluated the frequency of and reasons for discontinuation of protease inhibitor therapy in a cohort of HIV-infected patients in a prospective observational study. We included 230 HIV-infected patients who had started protease inhibitor therapy between November 1996 and July 1997. Mean baseline CD4 count was 138 cells/microl and HIV-RNA 4.5 log10. Forty-five percent of patients had prior AIDS and 77% had been treated with nucleoside analogues. Saquinavir-treated patients were at a less advanced stage of HIV disease. Overall, 41.3% of patients discontinued therapy, and their last HIV-RNA measured higher than that of patients who continued therapy: 4.07 vs. 2.70 log10 (p < 0.0001). Reasons for discontinuation of therapy were poor adherence (including abandonment) (18.6%), drug intolerance (12.1%), virological failure (7%) and physician decision (3.5%). In a multivariate model, factors associated with drug discontinuation were not taking indinavir (OR 0.26, 95% CI 0.12-0.59) and being pretreated with nucleoside analogues (OR 3.42, 95% CI 1.58-7.42). We concluded that in routine clinical practice a high proportion of patients discontinued protease inhibitors during the first 6 months of therapy, the main reason being the patient's own decision (abandonment or poor adherence). Psychological support and counselling are warranted in patients when initiating protease inhibitor therapy.

Venographic comparison of subcutaneous low-molecular weight heparin with oral anticoagulant therapy in the long-term treatment of deep venous thrombosis

PURPOSE

The primary objective of this study was to evaluate with venography the rate of thrombus regression after a fixed dose of low-molecular weight heparin (LMWH) per day for 3 months compared with oral anticoagulant therapy for deep venous thrombosis (DVT). Secondary endpoints were the comparisons of the efficacy and safety of both treatments.

METHODS

This study was designed as an open randomized clinical study in a university hospital setting. Of the 165 patients finally enrolled in the study, 85 were assigned LMWH therapy and 80 were assigned oral anticoagulant therapy. In the group randomized to oral anticoagulant therapy, the patients first underwent treatment in the hospital with standard unfractionated heparin and then coumarin for 3 months. Doses were adjusted with laboratory monitoring to maintain the international normalized ratio between 2.0 and 3.0. Patients in the LMWH group were administered subcutaneous injections of fixed doses of 40 mg enoxaparin (4000 anti-Xa units) every 12 hours for 7 days, and after discharge from the hospital, they were administered 40 mg enoxaparin once daily at fixed doses for 3 months without a laboratory control assay. A quantitative venographic score (Marder score) was used to assess the extent of the venous thrombosis, with 0 points indicating no DVT and 40 points indicating total occlusion of all deep veins. The rate of thrombus reduction was defined as the difference in quantitative venographic scores after termination of LMWH or coumarin therapy as compared with the scores obtained on the initial venographic results. The efficacy was defined as the ability to prevent symptomatic extension or recurrence of venous thromboembolism (documented with venograms or serial lung scans). The safety was defined as the occurrence of hemorrhages.

RESULTS

After 3 months of treatment, the mean Marder score was significantly decreased in both groups in comparison with the baseline score, although the effect of therapy was significantly better after LMWH therapy (49.4% reduction) than after coumarin therapy (24.5% reduction; P <.001). LMWH therapy and male gender were independently associated with an enhanced resolution of the thrombus. A lower frequency of symptomatic recurrent venous thromboembolism was also shown in patients who underwent treatment with LMWH therapy (9.5%) than with oral anticoagulant therapy (23.7%; P <.05), although this difference was entirely a result of recurrence of DVT. Bleeding complications were significantly fewer in the LMWH group than in the coumarin group (1. 1% vs 10%; P <.05). This difference was caused by minor hemorrhages. Coumarin therapy and cancer were independently associated with an enhanced risk of complications. Subcutaneous heparin therapy was well tolerated by all patients.

CONCLUSION

The patients who were allocated to undergo enoxaparin therapy had a significantly greater improvement in their quantitative venographic score, a significantly lower recurrence rate of symptomatic venous thromboembolism, and a significantly lower incidence of bleeding than patients who underwent treatment with coumarin. LMWH can be used on an outpatient basis as a safer and more effective alternative to classical oral anticoagulant therapy for the secondary prophylaxis of selected patients with DVT.

Diarrheagenicity evaluation of attenuated Vibrio cholerae O1 and O139 strains in the human intestine ex vivo

The recent spread of El Tor cholera in Latin America highlights the need for a safe and economical vaccine. The main approach for developing live recombinant vaccines has been to disarm known pathogenic strains of cholera toxin leaving intact antigens involved in protection. These recombinant vaccine candidates do not cause severe diarrhea, but they are too reactogenic for wide scale usage. We describe here a test capable of determining the diarrheagenic potential of attenuated V. cholerae strains. The functional test consists in the simultaneous recording of net water movement, electrical potential difference and short-circuit current across the human intestine ex vivo. We found that human tissues incubated with supernatants from the attenuated 638, 413 and 251a V. cholerae strains caused no changes in the ion conductances and water absorption in ileal and colon tissues allowing them to be assayed in volunteers.

The effect of the ingestion of ethanol on obstruction of the left ventricular outflow tract in hypertrophic cardiomyopathy

BACKGROUND

Ethanol causes vasodilation, which might have an adverse effect, due to increased obstruction of the left ventricular outflow tract, in patients with hypertrophic obstructive cardiomyopathy. We assessed the hemodynamic effects of the ingestion of ethanol, in an amount commonly consumed socially, in patients with hypertrophic cardiomyopathy.

METHODS

We performed echocardiography in 36 patients before and several times after the ingestion of either 50 ml of 40 percent ethanol or an isocaloric placebo with the aroma of rum. Each patient received both ethanol and placebo, on different days. The patients, but not the physicians, were blinded to the content of the drink. We measured the sizes of the left atrium and left ventricle, the left-ventricular-wall thickness, blood pressure, heart rate, the degree of systolic anterior motion of the mitral valve, and the pressure gradient across the left ventricular outflow tract.

RESULTS

The ingestion of ethanol regulated in a significant drop in the mean (+/- SD) systolic blood pressure (from 130.5 +/- 18.6 to 122.5 +/- 20.3 mm Hg, P<0.001), a significant increase in systolic anterior motion of the mitral valve (from a grade of 2.1 to a grade of 2.5, P<0.001), and a 63 percent increase in the mean gradient across the left ventricular outflow tract (from 38.1 +/- 26.5 to 62.2 +/- 42.4 mm Hg, P<0.001). These changes, which were not associated with symptoms, did not occur after the ingestion of placebo.

CONCLUSION

The ingestion of a small amount of ethanol caused an increase in the gradient across the left ventricular outflow tract in patients with hypertrophic obstructive cardiomyopathy, which could have and adverse clinical effect.

Identification of two isoforms of the Cak receptor kinase that are coexpressed in breast tumor cell lines

The Cak receptor kinase is a member of a novel family of receptors that are characterized by the unique structure of the ectodomains. We have identified a new isoform of Cak that differs from the original isolate by the deletion of 37 amino acids in the cytoplasmic juxtamembrane sequence. Analysis of the genomic sequence suggests that the two isoforms arise by exon skipping. The isoform-specific insert contains the motif NPXY, which was previously shown to be involved in diverse signaling function in a number of receptors. By RNase protection analyses, we found that the long isoform, Cak I is expressed at three- to sevenfold the abundance of the short isoform (Cak II). By Western blotting, Cak I receptor was found to be expressed in mouse embryos and in adult brain. Cak II protein was not detected in mouse embryos or adult tissues, but is abundantly expressed in some breast tumor cell lines. The expression profile of Cak suggests that its primary function is likely to be in developmental regulation. The coexpression of the Cak isoforms in some epithelial cell lines suggests that heterodimer formation may be a key feature in the function of the receptor.

Valve strands are strongly associated with systemic embolization: a transesophageal echocardiographic study

OBJECTIVES

We attempted to determine the prevalence of strands on native and prosthetic valves, as detected by transesophageal echocardiography, and to assess the relative risk for systemic emboli associated with these strands.

BACKGROUND

Fine threadlike strands, seen on native and prosthetic valves by transesophageal echocardiography, have been implicated in systemic embolization.

METHODS

During a 2-year period, 1,559 patients underwent transesophageal echocardiography at our center. Of these, 41 patients had strands and no other identifiable source of systemic emboli. They were matched for age, gender, history of hypertension and history of smoking with a control group of 41 patients without strands who also had no identifiable source of emboli. The risk of embolization in the two groups was compared.

RESULTS

Of 1,559 patients studied by transesophageal echocardiography, 86 (5.5%) had strands. Strands were far more common on mitral valves than on aortic valves. Of the patients with strands, 38% had had an event consistent with a systemic embolus, whereas 62% had not. Of 597 patients with an embolic event, 63 (10.6%) had strands, whereas only 23 (2.3%) of 962 patients without emboli had strands. In the case-control study, 33 (83%) of the 41 patients with strands without another source of embolism had emboli compared with only 12 (29%) of the 41 control patients without another source (odds ratio 10.0, 95% confidence interval 3.6 to 27.8, p = 0.00001).

CONCLUSIONS

Valvular strands visualized by transesophageal echocardiography are associated with systemic embolization.

Protruding atheromas of the aortic arch in symptomatic patients with carotid artery disease

Protruding aortic arch atheromas are associated with otherwise unexplained strokes and transient ischemic attacks. Therefore aortic atheromas also may be important in patients with carotid artery disease. Forty-five patients with > or = 50% carotid stenosis and stroke or transient ischemic attack within 6 weeks underwent transesophageal echocardiographic examination (TEE). They were matched for age, sex, and hypertension with 45 control subjects who had also had a recent cerebral event but in whom significant carotid stenosis was absent. Protruding aortic arch atheromas were present in 17 (38%) of 45 patients with carotid disease and only 7 (16%) of 45 of control subjects (p = 0.02). Mobile atheromas (with the greatest embolic potential) were present almost exclusively in case patients, 6 (13%) of 45, versus 1 (2%) of 45 control subjects (p = 0.05). Case patients with mobile atheromas had the most severe carotid stenosis ( > or = 80%). Cerebral symptoms were discordant with the side of the carotid stenosis in 10 case patients, and 4 had atheromas. In conclusion, protruding atheromas of the aortic arch are present in significant numbers of symptomatic patients with carotid artery disease. These atheromas may represent an additional cause of symptoms in patients with carotid stenosis. TEE to look for protruding aortic atheromas may be considered in patients with neurologic events despite the presence of significant carotid stenosis, especially if the symptoms are discordant with the side of carotid stenosis.

Cytomegalovirus ventriculoencephalitis in AIDS patients

We report 4 autopsy-proven cases of cytomegalovirus ventriculoencephalitis (CMV-VE) and a further case with dramatic clinical and radiological response to ganciclovir therapy. The diagnoses were based upon clinical features, cerebrospinal fluid (CSF) examination and either brain computerized tomography (CT) or magnetic resonance imaging (MRI), and confirmed by autopsy findings in 4 cases. All patients had previously had an AIDS-defining condition. CMV retinitis was diagnosed in 3 patients, 2 of them before the onset of encephalitis. CMV viremia was present in 4 patients. Examination of CSF demonstrated elevated protein and hypoglycorachia in all cases. CSF culture was negative for CMV in 3 of 3 patients. Periventricular enhancement was detected by MRI in 2 of 3 patients, but in only 1 of 5 patients by CT. Three patients received ganciclovir and 2 patients foscarnet therapy. All 4 patients died. Pathologic examination revealed periventriculitis with ependymal necrosis and CMV intranuclear inclusion bodies all 4 patients. One showed a marked neurological improvement and radiological resolution by MRI after 4 weeks of ganciclovir therapy. We conclude that CMV-VE should be suspected in HIV-infected patients who present with altered neurological status, CMV viremia or retinitis, hypoglycorachia and ventriculitis as demonstrated by MRI. Although more effective therapy is needed, ganciclovir may be beneficial, as shown in one of our patients.

High risk for vascular events in patients with protruding aortic atheromas: a prospective study

OBJECTIVES

The purpose of this study was to prospectively evaluate the risk of vascular events in patients with protruding aortic atheromas.

BACKGROUND

Protruding atheromas of the thoracic aorta have been shown to be associated with embolic disease in previous retrospective studies.

METHODS

During a 1-year period, 521 patients had transesophageal echocardiography. Of these, 42 patients had protruding atheromas and no other source of emboli. They were followed up for up to 2 years (mean follow-up 14 months) and compared with a control group without atheromas, matched for age, gender and hypertension.

RESULTS

Of 42 patients with atheromas, 14 (33%) had 19 vascular events during follow-up (5 brain, 2 eye, 4 kidney, 1 bowel, 7 lower extremity). Of 42 control patients, 3 (7%) had vascular events (2 brain, 1 eye). Univariate analysis identified only protruding atheromas as significantly correlating with events (p = 0.003). There was no positive correlation of events with age, gender, hypertension, smoking, family history, atrial fibrillation, valve replacement, antithrombotic drug use, diabetes or coronary disease. Multivariate analysis showed that only protruding atheromas independently predicted events (p = 0.005, odds ratio 4.3, 95% confidence interval 1.2 to 15.0). Nine patients died in the atheroma group versus six in the control group, but this was not statistically significant (p = 0.39).

CONCLUSIONS

Protruding atheromas seen on transesophageal echocardiography predict future vascular events.

Identification and chromosomal mapping of a receptor tyrosine kinase with a putative phospholipid binding sequence in its ectodomain

We have cloned a novel receptor tyrosine kinase that has an unusual ectodomain. The extracellular sequence consists of 416 amino acids and has none of the structural motifs that have been found in other receptor tyrosine kinases. The 150 amino acids in the amino terminus of the receptor is homologous to a putative phospholipid-binding sequence that is found also in other cell adhesion molecules such as the neuronal A5 antigen and coagulation factors V and VIII. The kinase domain has a short cytoplasmic tail and contains a short insert between subdomains I and II. The structure of this receptor kinase suggests that it belongs to a new family of receptors involved in cell-cell interactions. The cell adhesion kinase (Cak) is expressed at low levels in most adult tissues and expression is highest in the brain and lung. Using fluorescence in situ hybridization and interspecific backcross mapping, the Cak gene was localized to human chromosome 6 and mouse chromosome 17.

Sézary syndrome in an 11-year-old girl

All forms of cutaneous T-cell lymphoma are rare in children. We describe an 11-year-old girl who had generalized exfoliative erythroderma, intense pruritus, peripheral lymphadenopathy, mycosis cells in the skin and lymph nodes, and Sézary cells in the peripheral blood. Results of a biopsy specimen of involved skin showed changes consistent with mycosis fungoides. A classic case of Sézary syndrome has not previously been reported in childhood or preadolescence.

Trends in antimicrobial resistance of clinical isolates of Streptococcus pneumoniae in Bellvitge Hospital, Barcelona, Spain (1979-1990)

From January 1979 to December 1990 we studied the susceptibility of 1,492 pneumococcal strains isolated from adult patients in Bellvitge Hospital, Barcelona, Spain, to nine antimicrobial agents. Among clinically significant pneumococci, the incidence of penicillin-resistant strains increased from 4.3% in 1979 to 40% in 1990, and that of erythromycin-resistant strains also rose from 0% in 1979 to 9.4% in 1990. On the other hand, the incidence of strains resistant to tetracycline decreased from 76.1% to 37.6%, as did that of chloramphenicol-resistant strains, from 56.5% to 29.4%. The incidence of co-trimoxazole-resistant strains was about 40% throughout the study. Even more alarming was the finding that about 70% of penicillin-resistant strains showed multiple resistance to non-beta-lactam antibiotics. All pneumococci were susceptible to vancomycin, and all but six were susceptible to rifampin. We observed that isolates from cerebrospinal fluid and the respiratory tract were significantly more resistant to penicillin than were isolates from blood. The majority of strains (95%) belonged to serogroups or serotypes included in the 23-valent pneumococcal vaccine and 77.6% of penicillin-resistant strains belonged to groups 23, 6, 9, and 19.

Protruding atheromas in the thoracic aorta and systemic embolization

OBJECTIVE

To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization.

DESIGN

Case-control study.

SETTING

A referral hospital.

PATIENTS

A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients.

MEASUREMENTS

Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli.

MAIN RESULTS

Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0).

CONCLUSION

Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.

Comparison of cardiac catheterization and Doppler echocardiography in the decision to operate in aortic and mitral valve disease

Clinical decisions utilizing either Doppler echocardiographic or cardiac catheterization data were compared in adult patients with isolated or combined aortic and mitral valve disease. A clinical decision to operate, not operate or remain uncertain was made by experienced cardiologists given either Doppler echocardiographic or cardiac catheterization data. A prospective evaluation was performed on 189 consecutive patients (mean age 67 years) with valvular heart disease who were being considered for surgical treatment on the basis of clinical information. All patients underwent cardiac catheterization and detailed Doppler echocardiographic examination. Three sets of two cardiologist decision makers who did not know patient identity were given clinical information in combination with either Doppler echocardiographic or cardiac catheterization data. The combination of Doppler echocardiographic and clinical data was considered inadequate for clinical decision making in 21% of patients with aortic and 5% of patients with mitral valve disease. The combination of cardiac catheterization and clinical data was considered inadequate in 2% of patients with aortic and 2% of patients with mitral valve disease. Among the remaining patients, the cardiologists using echocardiographic or angiographic data were in agreement on the decision to operate or not operate in 113 (76% overall). When the data were analyzed by specific valve lesion, decisions based on Doppler echocardiography or catheterization were in agreement in 92%, 90%, 83% and 69%, respectively, of patients with aortic regurgitation, mitral stenosis, aortic stenosis and mitral regurgitation. Differences in cardiac output determination, estimation of valvular regurgitation and information concerning coronary anatomy were the main reasons for different clinical management decisions. These results suggest that for most adult patients with aortic or mitral valve disease, alone or in combination, Doppler echocardiographic data enable the clinician to make the same decision reached with catheterization data.

Stiffness and strength tailoring of a hip prosthesis made of advanced composite materials

This work is concerned with the design of hip prostheses using advanced fiber reinforced composite materials. The major focus of the study is to evaluate how the stiffness and strength of composite hip prostheses can be affected by variations in ply orientation and stacking sequence for a selected manufacturing method. This investigation involved both analytical and experimental work. An analytical model was developed which consists of a stress analysis and a failure analysis. A finite element program was developed during the course of the investigation for analyzing stresses, strains, and deformations of composite stems with a simplified configuration. Failure and mode of failure were predicted by appropriately selected failure criteria. Experiments were also performed on T300/976 graphite/epoxy composites to verify the analysis and the computer calculations. Both testing and analysis accounted for the various combinations of in-plane and out-of-plane (torsion) loading that can act on the prosthetic hip. Simplified composite stems with a 120 layer thickness were fabricated and tested. An excellent agreement was found between the measured strain data and the numerical calculations. Using the program, parametric studies were performed. It was found that an optimal design of hip stems can be achieved by using advanced fiber-reinforced composite materials, but great care must be taken when selecting the appropriate ply orientation and stacking sequence for a chosen fabrication method.

Odor and taste aversions conditioned in anesthetized rats

Conditioned flavor aversions (CFA) are acquired by anesthetized rats but effects of various anesthetics on acquisition of aversions for separate odor and taste components are unknown. In Experiment 1, rats drank tomato juice and then were tranquilized with "Innovar-Vet" or "Rompun" before receiving injections of lithium chloride. Neither drug interfered with acquisition of aversions. Innovar-Vet alone produced no aversions; Rompun alone produced mild aversions but did not enhance aversions when combined with lithium. In Experiments 2 and 3, rats received a compound odor/taste cue as they drank and then were anesthetized with pentobarbital before lithium injections. Anesthesia alone produced negligible aversions but facilitated taste-lithium aversions. During odor tests, odor aversions were weaker than taste aversions. These data extend previous work and suggest that CFA does not result from ordinary classical conditioning. A tripartite notation that unites CFA and classical conditioning is discussed.

Efficient malignant transformation of rat embryo fibroblasts by genomic DNA from Walker carcinoma cells

DNA isolated from Walker carcinoma ascites cells was transfected into primary rat embryo fibroblasts (REF), selecting transformed cells by growth in soft agar after prolonged propagation in monolayer. Both high molecular weight genomic DNA and a partially purified mitochondrial DNA fraction were able to transform REF with high efficiency, whereas pure mitochondrial DNA failed to elicit a transformed phenotype. Hybridization experiments showed that the mitochondrial DNA fraction contained DNA species of presumably extramitochondrial origin. Colonies were cloned into morphologically transformed, foci-forming, immortalized cell lines, showing different degrees of chromosomal alterations, tumorigenicity, and production of cell growth factors. These results indicate that although REF are refractory to genomic neoplastic DNA or to single cloned oncogenes in the absence of enhancers, they can be efficiently transformed by chromosomal DNA from a highly malignant tumor under conditions selecting against the remaining normal cells.

Odor and taste aversions conditioned in anesthetized rats

Conditioned flavor aversions (CFA) are acquired by anesthetized rats but effects of various anesthetics on acquisition of aversions for separate odor and taste components are unknown. In Experiment 1, rats drank tomato juice and then were tranquilized with "Innovar-Vet" or "Rompun" before receiving injections of lithium chloride. Neither drug interfered with acquisition of aversions. Innovar-Vet alone produced no aversions; Rompun alone produced mild aversions but did not enhance aversions when combined with lithium. In Experiments 2 and 3, rats received a compound odor/taste cue as they drank and then were anesthetized with pentobarbital before lithium injections. Anesthesia alone produced negligible aversions but facilitated taste-lithium aversions. During odor tests, odor aversions were weaker than taste aversions. These data extend previous work and suggest that CFA does not result from ordinary classical conditioning. A tripartite notation that unites CFA and classical conditioning is discussed.

Comparative susceptibilities of penicillin-resistant pneumococci to co-trimoxazole, vancomycin, rifampicin and fourteen beta-lactam antibiotics

Eighty-four isolates of penicillin-resistant pneumococci were tested for susceptibility to vancomycin, rifampicin, cotrimoxazole, and 14 beta-lactam antibiotics by agar and microbroth dilution methods. Twenty-three were from adult patients with pneumococcal disease, 57 from nasopharingeal carriers (preschool children) and four were resistant South African isolates. For all isolates tested, imipenem (N-formimidoyl thienamycin), rifampicin, ceftriaxone and cefotaxime had the greatest activity ( MIC90 : 0 X 12, 0 X 25, 0 X 5 mg/l, respectively). Cefoxitin and latamoxef were the least active of the drugs studied. The remaining beta-lactams tested had less activity than that of penicillin. All strains were inhibited by 1 mg/l of vancomycin and all but one were resistant to cotrimoxazole. The excellent in-vitro activities of the newer beta-lactam agents (ceftriaxone, cefotaxime and, particularly, imipenem ) and vancomycin against penicillin-resistant pneumococci offer a considerable promise for their use in the treatment of pneumococcal meningitis caused by these strains.