Oral anti-pneumococcal activity and pharmacokinetic profiling of a novel peptide deformylase inhibitor

OBJECTIVE

BB-81384, a novel peptide deformylase (PDF) inhibitor, was characterized in terms of enzyme inhibition profile, antibacterial activity, rodent pharmacokinetics and oral efficacy in murine infection models.

METHODS

MICs were determined by standard NCCLS broth microdilution. Selectivity of metalloenzyme inhibition was determined with a limited panel of enzymes via standard biochemical assays. Profiling of the pharmacokinetics and select tissue disposition in mice was determined and compared with that of the macrolide, azithromycin. In vivo murine efficacy studies using Streptococcus pneumoniae were conducted using a peritonitis model, as well as lung and thigh burden models of infection.

RESULTS

BB-81384 selectively inhibited PDF with an IC(50) approximately 10 nM and with MICs < 0.5 mg/L against most S. pneumoniae pathogens. Pharmacokinetic analysis revealed good oral bioavailability and moderate clearance and volume of distribution. BB-81384 partitioning to lung tissue was similar in terms of magnitude and kinetics to that of the plasma compartment. Single-administration oral efficacy in a mouse peritonitis model was evident with an ED(50) of 30 mg/kg. BB-81384 reduced the bacterial load by approximately 5 and 3 log units in organ-burden models of lung and thigh infection, respectively.

CONCLUSION

BB-81384, a novel PDF inhibitor with good activity against S. pneumoniae in vitro, was the first compound of this class to be profiled for oral pharmacokinetics and tissue disposition and to demonstrate oral anti-pneumococcal efficacy in mice.

Beneficial effects of HLA class II incompatibility in living donor liver transplantation

OBJECTIVE

To analyze the impact of HLA matching in both patient and graft evolution after LDLT.

MATERIAL AND METHODS

Twenty recipients underwent LDLT with follow-up of 3 to 30 months. HLA typing was performed on all donor-recipient pairs; class I antigens were typed using serological methods and class II loci (DRB1 and DQB1) using low-resolution molecular typing. Recipient sera were cross-matched with donor lymphocytes. Antigen mismatches were analyzed for each locus individually, for each class as a whole and for HLA class I immunogenic triplets according to HLA Matchmaker software.

RESULTS

Eighteen of 20 donor-recipient pairs were HLA haploidentical. All but one of the recipients had a negative cross-match before transplantation. While there was not a statistically significant correlation between HLA class I mismatches and the incidence of acute rejection episodes, HLA class II matching in DRB1 and DQB1 loci appeared to be associated with a higher incidence of acute rejection episodes after LDLT. Both host-versus-graft (HvG) and graft-versus-host (GvH) HLA class II compatibilities correlated with rejection episodes, especially for the GvH direction.

CONCLUSIONS

HLA class II matching for DRB1 and DQB1 loci appears to be associated with a higher incidence of acute rejection episodes after LDLT. In this study, mismatches in class I HLA antigens are not related to an higher incidence of acute rejection episodes nor other complications after LDLT. Further studies are needed to unveil the role of HLA matching in LDLT.

How to target estrogen receptor-negative breast cancer?

Estrogen receptor (ER)-positive breast cancers generally have a better prognosis and are often responsive to anti-estrogen therapy, which is the first example of a successful therapy targeted on a specific protein, the ER. Unfortunately ER-negative breast cancers are more aggressive and unresponsive to anti-estrogens. Other targeted therapies are thus urgently needed, based on breast cancer oncogene inhibition or suppressor gene activation as far as molecular studies have demonstrated the alteration of expression, or structure of these genes in human breast cancer. Using the MDA-MB.231 human breast cancer cell line as a model of ER-negative breast cancers, we are investigating two of these approaches in our laboratory. Our first approach was to transfect the ER or various ER-deleted variants into an ER-negative cell line in an attempt to recover anti-estrogen responsiveness. The unliganded receptor, and surprisingly estradiol, were both found to inhibit tumor growth and invasiveness in vitro and in vivo. The mechanisms of these inhibitions in ER-negative cancer cells are being studied, in an attempt to target the ER sequence responsible for such inhibition in these cancer cells. Another strategy is trying to inhibit the activity or expression of an oncogene specifically overexpressed in most breast cancers. This approach was recently shown by others to be efficient in breast cancer therapy with HER2-Neu oncogene amplification using Herceptin. Without excluding other molecular putative targets, we have focused our research on cathepsin D as a potential target, since it is often overexpressed in aggressive human breast cancers, including ER-negative tumors, and rarely associated with HER2-Neu amplification. Our first results obtained in vitro on cell lines and in vivo in tumor xenografts in nude mice, illustrate that the mode of action of cathepsin D in breast cancer is useful to guide the development of these therapies. In the past 20 years we have learned that the action of cathepsin D is complex and involves both intracellular and extracellular activities due to its proteolytic activity and to interactions with membrane components without catalytic activity. Each of these mechanisms could be potentially inhibited in an attempt to prevent tumor growth. Breast cancer is a very heterogeneous and multigenic disease and different targeted therapies adapted to each category of breast cancer are therefore required. Validated assays in the primary tumor of molecular markers such as ER, HER2-Neu and cathepsin D should help to predict which targeted therapy should be applied to cure breast cancer patients.

Factors associated with time to sputum smear conversion in active pulmonary tuberculosis

OBJECTIVE

To ascertain the factors affecting the time between the initiation of treatment and obtaining three negative sputum smears.

DESIGN

In a study of 109 patients with pulmonary tuberculosis, the main variable was the period during which the patients had sputum smears once treatment was initiated. Multivariate analysis (multiple linear regression) was performed to document those variables independently associated with time to conversion.

RESULTS

The patients had positive smears for a mean of 28.63 days. The most frequent radiographic pattern was cavitary disease (36.7%). HIV co-infection was present in 38.5% of the patients. HIV-infected patients showed a cavitation pattern in only 9.6% vs 52.2% of patients without HIV infection (P < 0.001). The variables that showed a statistically significant and independent relationship with the time to sputum smear conversion were pulmonary radiographic pattern, age and erythrocyte sedimentation rate (ESR).

CONCLUSIONS

ESR, age and the presence of cavitary disease seem to be factors associated with a longer time to sputum smear conversion in patients with active pulmonary tuberculosis. However, HIV co-infection is associated with a shorter time to sputum conversion. A key factor is therefore the presence or not of cavitation, independently of HIV infection.

Synaptic process in the rat (Rattus norvegicus): Influence of methodology on results

Synaptonemal complex (SC) analysis is a widely used method for assessing the effects of genotoxic agents in germ cells. Although the evolution of the SCs and their related annexed structures, such as nucleoli, has been well established, sometimes it is difficult to assess whether the abnormal features observed correspond to genotoxic effects or to an artefact related to the method used to obtain the SC preparations. In this article, we describe a new method of obtaining SC preparations for electron microscopy, as well as the results of a study of the first meiotic prophase in oocytes and spermatocytes of the rat (Rattus norvegicus Sprague Dawley) in which we analysed how the methodology used can influence the results. Besides important sex-specific differences, mainly during desynapsis (diplotene), a relationship between several bivalents and nucleolar structures, that in some cases could disturb the synaptic process, was observed in oocytes. At the same time, the characteristic SC fragmentation in oocytes was verified, but this fragmentation, in addition to a sex-specific component, was influenced by the method itself. By reducing to a minimum the artefacts produced by the method, it is possible to optimise the analysis of SCs as a method of testing genotoxic effects in the germ line.

Air reduction of intussusception

AIM

To show that intussusception in children is reducible in most cases, using air.

METHODS

Initially we used a barium enema to treat paediatric intussusception. Now we use an air enema. We consider the latter reduction technique to be the method of choice in the treatment of intussusception in childhood.

RESULTS

Over a period of 21 years, we have treated 151 patients presenting with intussusception. In a group of 130 children treated with barium enema we managed to reduce the intussusception in 110 cases (84.6 %). We used air pressure to treat a second group of 21 children; the success rate in this group was 100 %.

CONCLUSIONS

In order to avoid a surgical operation this technique must become more generally known. We are of the opinion that if the method is applied correctly, it is almost always possible to correct intussusception using air.

Mitochondrial DNA depletion: mutations in thymidine kinase gene with myopathy and SMA

BACKGROUND

The mitochondrial DNA (mtDNA) depletion syndrome (MDS) is an autosomal recessive disorder of early childhood characterized by decreased mtDNA copy number in affected tissues. Recently, MDS has been linked to mutations in two genes involved in deoxyribonucleotide (dNTP) metabolism: thymidine kinase 2 (TK2) and deoxy-guanosine kinase (dGK). Mutations in TK2 have been associated with the myopathic form of MDS, and mutations in dGK with the hepatoencephalopathic form.

OBJECTIVES

To further characterize the frequency and clinical spectrum of these mutations, the authors screened 20 patients with myopathic MDS.

RESULTS

No patient had dGK gene mutations, but four patients from two families had TK2 mutations. Two siblings were compound heterozygous for a previously reported H90N mutation and a novel T77M mutation. The other siblings harbored a homozygous I22M mutation, and one of them had evidence of lower motor neuron disease. The pathogenicity of these mutations was confirmed by reduced TK2 activity in muscle (28% to 37% of controls).

CONCLUSIONS

These results show that the clinical expression of TK2 mutations is not limited to myopathy and that the myopathic form of MDS is genetically heterogeneous.

The efficacy of chloroquine for the treatment of acute, uncomplicated, Plasmodium falciparum malaria in Laos

To assess the local efficacy of chloroquine for the treatment of acute, uncomplicated, Plasmodium falciparum malaria, children and adults from Sekong province (an area of Laos with a low intensity of transmission) were tested in a 28-day, in-vivo study. Complete data were collected from 88 of the 102 subjects enrolled between October 1999 and September 2000. After genotypic analysis to distinguish recrudescing infections from re-infections, 35 (39.7%, with a 95% confidence interval of 29.5%-50.7%) of these 88 patients were considered treatment failures. These results seriously question the use of chloroquine as the first-line treatment for P. falciparum malaria in the study area.

Chromosomal homologies between Cebus and Ateles (primates) based on ZOO-FISH and G-banding comparisons

ZOO-FISH (Fluorescent "in vitro" hybridization) was used to establish the chromosomal homology between humans (HSA) and Cebus nigrivitatus (CNI) and Ateles belzebuth hybridus (ABH). These two species belong to different New World monkey families (Cebidae and Atelidae, respectively) which differ greatly in chromosome number and in chromosome morphology. The molecular results were followed by a detailed banding analysis. The ancestral karyotype of Cebus was then determined by a comparison of in situ hybridization results, as well as chromosomal morphology and banding in other Platyrrhini species. The karyotypes of the four species belonging to the genus Cebus differ from each other by three inversions and one fusion as well as in the location and amounts of heterochromatin. Results obtained by ZOO-FISH in ABH are in general agreement with previous gene-mapping and in situ hybridization data in Ateles, which show that spider monkeys have highly derived genomes. The chromosomal rearrangements detected between HSA and ABH on a band-to-band basis were 27 fusions/fissions, 12 centromeric shifts, and six pericentric inversions. The ancestral karyotype of Cebus was then compared with that of Ateles. The rearrangements detected were 20 fusions/fissions, nine centromeric shifts, and five inversions. Atelidae species are linked by a fragmentation of chromosome 4 into three segments forming an association of 4/15, while Ateles species are linked by 13 derived associations. The results also helped clarify the content of the ancestral platyrrhine karyotype and the mode of chromosomal evolution in these primates. In particular, associations 2/16 and 5/7 should be included in the ancestral karyotype of New World monkeys.

Distribution of intrachromosomal telomeric sequences (ITS) on Macaca fascicularis (Primates) chromosomes and their implication for chromosome evolution

The intrachromosomal location of the telomeric sequence in the crab-eating macaque, Macaca fascicularis (F. Cercopithecidae, Catarrhini) has been analysed by fluorescent in situ hybridisation with a long synthetic (TTAGGG)(n) probe. A total of 237 metaphases was analysed. As expected, all telomeres hybridised with the probe and 90 intrachromosomal loci with different hybridisation frequencies were also detected. The chromosomal location of interstitial telomeric sequences in M. fascicularis and in Homo sapiens was then compared, 37 sites (41.11%) being found to be conserved. Some of these sequences can be derived from rearrangements, such as inversions (MFA13q23) or fusions (MFA2p13 and MFA13p12), that have taken place during karyotype evolution.

[Eosinophilic ulcer of the oral mucosa: 11 cases]

BACKGROUND

The eosinophilic ulcer is a lesion of the oral mucosa, that has been infrequently described in the literature. This is a benign and self-limiting lesion of unknown origin.

CASE REPORTS

In this article, eleven new cases of eosinophilic ulcer of the oral mucosa are presented. The clinical, histologic and evolutive features are reviewed.

DISCUSSION

Recurrent trauma is clearly involved in the pathogenesis of this entity.

Dynamics and stability of legged locomotion in the horizontal plane: a test case using insects

Motivated by experimental studies of insects, we propose a model for legged locomotion in the horizontal plane. A three-degree-of freedom, energetically conservative, rigid-body model with a pair of compliant virtual legs in intermittent contact with the ground allows us to study how dynamics depends on parameters such as mass, moment of inertia, leg stiffness, and length. We find periodic gaits, and show that mechanics alone can confer asymptotic stability of relative heading and body angular velocity. We discuss the relevance of our idealized models to experiments and simulations on insect running, showing that their gait and force characteristics match observations reasonably well. We perform parameter studies and suggest that our model is relevant to the understanding of locomotion dynamics across species.

Attention-deficit/hyperactivity disorder (ADHD): feasibility of linkage analysis in a genetic isolate using extended and multigenerational pedigrees

Segregation analyses converge in explaining the predisposition to attention-deficit/hyperactivity disorder (ADHD) as the consequence of a major gene and exclude purely environmental or cultural transmission. As a result of the ADHD phenotype restrictions, collection of extended families or design of linkage studies using families has been extremely difficult and thus currently linkage studies have been performed using only concordant or discordant sib-pairs rather than large families. On the other hand, intergenerational studies are represented by the transmission disequilibrium test (TDT) using trios. We collected pedigree data on ADHD from the Paisa community from Antioquia, Colombia, a genetic isolate. The goal of this study was to genetically map a putative gene predisposing to ADHD in a set of 27 multigenerational Paisa families. Here we present the results of a power simulation using SIMLINK to detect linkage of ADHD. ADHD was assumed to be a dichotomous trait with incomplete penetrance and a phenocopy rate of 3% in males and 0.2% in females. We simulated cosegregation of the trait and a marker locus in our pedigrees. We assumed Hardy-Weinberg and linkage equilibrium, equally frequent marker alleles and evaluated power at several recombination fractions between the trait and marker loci. Also, the ADHD trait was assumed to be genetically heterogeneous and different functions of age-dependent penetrance were simulated. We found exceptionally good power to detect linkage (expected LOD > 14 if theta is 0.1 or less), and that the presence of heterogeneity up to 50% does not affect substantially the projected LOD scores even for a theta recombination value of 0.05 (eLOD > 5.87). Having now obtained blood samples and confirmatory interviews in five families (representing 20% of the projected number of families), we performed a new analysis. The expected mean LOD in these five families reached values close to 10 and remained invariant when heterogeneity and different penetrance models were considered. We discuss the relative benefits of using extended and multigenerational families for genetic mapping studies as opposed to using nuclear families, affected sib pairs or sporadic cases which require the collection of over 1000 analytical units to get the same power exhibited by the small number of pedigrees described here.

Is Doppler tissue velocity during early left ventricular filling preload independent?

BACKGROUND

Transmitral Doppler flow indices are used to evaluate diastolic function. Recently, velocities measured by Doppler tissue imaging have been used as an index of left ventricular relaxation.

OBJECTIVE

To determine whether Doppler tissue velocities are influenced by alterations in preload.

METHODS

Left ventricular preload was altered in 17 patients (all men, mean (SD) age, 49 (8) years) during echocardiographic measurements of left ventricular end diastolic volume, maximum left atrial area, peak early Doppler filling velocity, and left ventricular myocardial velocities during early filling. Preload altering manoeuvres included Trendelenberg (stage 1), reverse Trendelenberg (stage 2), and amyl nitrate (stage 3). Systolic blood pressure was measured at each stage.

RESULTS

In comparison with baseline, left ventricular end diastolic volume (p = 0.001), left atrial area (p = 0.003), peak early mitral Doppler filling velocity (p = 0.01), and systolic blood pressures (p = 0.001) were all changed by preload altering manoeuvres. Only left ventricular myocardial velocity during early filling remained unchanged by these manoeuvres.

CONCLUSIONS

In contrast to standard transmitral Doppler filling indices, Doppler tissue early diastolic velocities are not significantly affected by physiological manoeuvres that alter preload. Thus Doppler tissue velocities during early left ventricular diastole may provide a better index of diastolic function in cardiac patients by providing a preload independent assessment of left ventricular filling.

Evaluating changes in sexual functioning in depressed patients: sensitivity to change of the CSFQ

Accurately evaluating alterations in sexual functioning requires a validated instrument that measures clinically relevant change over time. One-hundred one depressed patients from 15 Spanish out-patient clinics completed the Changes in Sexual Functioning Questionnaire (CFSQ; Clayton, McGarvey, & Clavet, 1997) at baseline and after 6 months of treatment with fluoxetine, nefazodone, paroxetine, or venlafaxine. Sexual desire/interest showed a nearly substantial floor effect (30% of patients indicated the maximum score) for women in the nefazodone group at baseline and in the paroxetine group at final visit. The percentage of dimensions recording change was greater for women (80%) than for men (20%) in the nefazodone group (improving changes) and greater for men (40%) than for women (20%) in the paroxetine group (worsening changes). Highest effect sizes were found on sexual desire/frequency with improvement in women in the nefazodone group (SES = 0.49), and on orgasm/ejaculation with worsening in men in the paroxetine group (SES = -1.45). In conclusion, the CSFQ is sensitive to bidirectional changes and is appropriate for measuring sexual dysfunction.

Pyloric relaxation regulated via intramural neural pathway of the antrum

Current information about pyloric relaxation is not sufficient. For this reason, our study aimed at measuring pyloric relaxation correctly and determining the role of the intrinsic and extrinsic neural pathway in pyloric relaxation. Five groups of dogs were used: five dogs had an intact gastrointestinal tract (control group); five dogs had transection and reanastomosis of the antrum 3 cm proximal to the pylorus (antral transection group); five dogs had extrinsic pyloric denervation (denervation group); five dogs had transection and reanastomosis of the antrum with extrinsic pyloric ring denervation (transection with denervation group); and five dogs had truncal vagotomy (vagotomy group). Gastropyloroduodenal motility was recorded by a strain-gauge force transducer in conscious dogs. In the control and denervation groups, pyloric relaxation was observed only during phase III of the interdigestive migrating motor complex. In the antral transection, transection with denervation, and vagotomy groups, pyloric relaxation was not observed in either the interdigestive or the postprandial state. The frequency of pyloric contractions increased in these groups in comparison with the control group. In conclusion, the results suggest that pyloric relaxation occurred during phase III to expel undigested particles from the stomach and that descending antral intramural pathways play an important role in the control of pyloric relaxation.

A mutated cathepsin-D devoid of its catalytic activity stimulates the growth of cancer cells

Cathepsin-D, a lysosomal aspartyl proteinase, is highly secreted by breast cancer cells and its over-expression by transfection stimulates cancer cell proliferation. The mechanism by which this protease affects proliferation remains, however, unknown. In order to determine whether proteolytic activity is necessary, we abolished its enzymatic activity using site-directed mutagenesis followed by stable transfection in 3Y1-Ad12 cancer cells. Substitution of the aspartic acid residue 231 by an asparagine residue in its catalytic site abrogated the cathepsin-D proteolytic activity but did not affect its expression level, processing or secretion. However, like wild-type cathepsin-D, this mutated catalytically-inactive cathepsin-D retained its capacity to stimulate proliferation of cells embedded in Matrigel or collagen I matrices, colony formation in soft agar and tumor growth in athymic nude mice. Addition on the mock-transfected cells, of either conditioned media containing the wild-type or the mutated pro-cathepsin-D, or of the purified mutated pro-cathepsin-D, partially mimicked the mitogenic activity of the transfected cathepsin-D, indicating a role of the secreted pro-enzyme. Moreover, addition of two anti-cathepsin-D antibodies on the cathepsin-D transfected cells inhibited their proliferation, suggesting an action of the secreted pro-cathepsin-D via an autocrine loop. A synthetic peptide containing the 27-44 residue moiety of the cathepsin-D pro-fragment was, however, not mitogenic suggesting that a receptor for the pro-fragment was not involved. Furthermore, the cathepsin-D mitogenicity was not blocked by inhibiting the interaction of pro-cathepsin-D with the mannose-6-phosphate receptors. Our results altogether demonstrate that a mutated cathepsin-D devoid of catalytic activity is still mitogenic and suggest that it is acting extra-cellularly by triggering directly or indirectly a yet unidentified cell surface receptor.