[Leprosy in French Guyana: a retrospective study from 1997 to 2006]

French Guyana borders Brazil with the second highest number of cases of leprosy in the world. The purpose of this retrospective study of leprosy cases diagnosed in Guyana between January 1997 and December 2006 was to calculate the incidence of the disease and to identify any special clinical and epidemiological features. A total of 90 new cases were recorded during the study period for a mean incidence of 0.53 cases/10,000 inhabitants/year. Since this incidence is below the 1/10,000 threshold defined by the World Health Organization, leprosy is no longer considered as a major public health issue in French Guyana. However it must be noted that while the number of "native leprosy" cases has declined, the number of Brazilian cases has increased (p<0.01). Brazilian leprosy has different epidemiological features, i.e., dominance of multibacillary forms and high incidence in gold panning and western regions of the country where the incidence is over 1/10,000 inhabitants/year.

Genotypic characterization and phylogenetic analysis of Cryptosporidium sp. from domestic animals in Brazil

The purpose of the present study was the genetic characterization, sequencing and phylogenetic analysis of 18S rDNA sequences of Cryptosporidium isolates obtained from different animal hosts in Brazil. Fecal samples containing Cryptosporidium oocysts were obtained from chickens, ducks, quails, guinea pigs, dairy calves, dogs and cats. For amplification of 18S rDNA sequences the Secondary-PCR product of the extracted DNA from fecal suspension of each studied animal was utilized. The primary genetic characterization of Cryptosporidium sp. was performed using RFLP with the enzymes SspI and VspI. DNA samples were sequenced and subjected to phylogenetic analysis. The results showed C. baileyi infecting two ducks and one quail and C. melagridis infecting one chicken. The sequences obtained from Cryptosporidium sp. infecting guinea pigs were not identified within groups of known Cryptosporidium species. The isolates found parasitizing cats and one dog were diagnosed as C. felis and C. canis, respectively. One isolate of calf origin was identified as C. parvum. The phylogenetic analysis showed clear distribution of isolates between two Cryptosporidium sp. groups according to their gastric or intestinal parasitism. A great genetic distance was observed between C. felis and C. canis from Brazil when compared to the reference sequences obtained from GenBank. The results obtained during this study constitute the first report of rDNA sequences from C. baileyi, C. meleagridis, C. felis, C. canis and C. parvum isolated in Brazil.

Rapid and label-free nanomechanical detection of biomarker transcripts in human RNA

The availability of entire genome sequences has triggered the development of microarrays for clinical diagnostics that measure the expression levels of specific genes. Methods that involve labelling can achieve picomolar detection sensitivity, but they are costly, labour-intensive and time-consuming. Moreover, target amplification or biochemical labelling can influence the original signal. We have improved the biosensitivity of label-free cantilever-array sensors by orders of magnitude to detect mRNA biomarker candidates in total cellular RNA. Differential gene expression of the gene 1-8U, a potential marker for cancer progression or viral infections, has been observed in a complex background. The measurements provide results within minutes at the picomolar level without target amplification, and are sensitive to base mismatches. This qualifies the technology as a rapid method to validate biomarkers that reveal disease risk, disease progression or therapy response. We foresee cantilever arrays being used as a tool to evaluate treatment response efficacy for personalized medical diagnostics.

Multiple neonatal staphylococcal cold abscesses of the large folds

BACKGROUND

We describe three neonates who presented around the tenth day of life with multiple bilateral fluctuating cold abscesses situated in the lymph node areas, with secondary fistulation but without associated fever or general symptoms.

RESULTS

In all cases, Staphylococcus aureus was found in the abscesses and the umbilicus with similar antibiograms. The evolution was good and the children remained in good health afterwards.

CONCLUSION

Disseminated neonatal staphylococcal infections with a benign evolution are not commonly described in the medical literature. Clinically, cold inflammatory abscesses of the large folds associated with omphalitis may correspond to either transient bacteriemia well controlled in an immunocompetent host or more likely a local contamination process.

Camptocormia associated with focal myositis in multiple-system atrophy

Camptocormia (CC) or pronounced forward flexion of the trunk is a common symptom of Parkinson's disease. We describe 2 patients with probable, respectively possible multiple-system atrophy and CC. Magnetic resonance imaging of the erector trunci showed focal patchy hyperintensities with gadolinium enhancement and muscle biopsy was indicative of variably pronounced focal myositis. CC was progressive and the major handicap for both patients after 1 and 1.5 years of follow-up, respectively. The therapeutic response was poor. Similarities with the dropped-head syndrome suggest that the muscle pathology may be either the primary cause of CC, a focal reaction to the CC posture, or a coincident syndrome of old age.

Natural infection by Giardia sp. and Cryptosporidium sp. in dairy goats, associated with possible risk factors of the studied properties

Visits were made to six farms raising dairy goats located in the mountain region of the state of Rio de Janeiro, Brazil, seeking to identify parasitism by Giardia sp. and Cryptosporidium sp. During the visits, fecal samples were collected from approximately 10% of the stock of each property. A questionnaire was given to the keepers on each property to obtain data for epidemiological analysis. A total of 105 fecal samples was collected, 56 from adult animals (over 12 months of age) and 49 from juvenile animals (less than 12 months). The fecal material was processed and subjected to the centrifuge-flotation technique and to staining with safranine-methylene blue. Protozoans of the genus Cryptosporidium were found at two properties, where the hygiene conditions of the installations were considered average and the stalls were made of wood slats raised from the ground. A total of five (4.8%) of the samples was found to be positive for the presence of this protozoan, all from juvenile animals. Cysts of the genus Giardia were found at two properties. Of the 105 samples analyzed, the protozoan was detected in 15 (14.3%), all in juvenile animals, and animals in the age range of 1-3 months had significantly more infections. Age, sanitary condition of the stalls and stalls made of wood slats and raised from the ground, can be pointed out as possible risk factors for infection by Giardia sp. and Cryptosporidium sp. The study reports for the first time the occurrence of Cryptosporidium sp. and Giardia sp. in goats in the state of Rio de Janeiro.

Comparison between natural infection by Cryptosporidium sp., Giardia sp. in dogs in two living situations in the West Zone of the municipality of Rio de Janeiro

In order to compare natural infection by Cyptosporidium sp. and Giardia sp. in clinically healthy dogs living in two situations (animal shelter and household pets), we conducted 166 faecal exams using the technique of centrifugation-flotation in a sugar-saturated solution. Of the faecal samples, 94 came from shelter dogs and 72 from house pets. Eighty-two (49.4%) contained parasite eggs, cysts or oocysts. Of these, four (2.41%) contained Cryptosporidium sp. oocysts and 52 (31.33%) contained Giardia sp. cysts. There was no statistically significant difference between the origin of the dogs and Cryptosporidium sp. infection. Infection by Cryptosporidium sp. was not associated with the living conditions and sex. With respect to Giardia sp., we observed a statistically significant difference (p < 0.001) between the shelter dogs (45%) and the household pets 12.3%. There was no association of infection by Giardia sp. with age or sex.

Sexual conflict in Sepsis cynipsea: female reluctance, fertility and mate choice

Sexual conflict can elevate mating costs via male inflicted damage to females. Possible selective advantages to males include decreasing the likelihood that females remate and/or increasing females' current reproductive investment in a manner analogous to terminal reproductive investment. We investigated female mating behaviour relative to their number of previous copulations in the fly Sepsis cynipsea, and whether males accepted as first mates were more likely to be accepted again. Females were more likely to remate with new rather than original males, although there was no associated fitness benefit, and in contrast to theoretical predictions, females became less reluctant to remate as the number of previous copulations increased. Additionally, females did not increase reproductive investment as would be expected if they were ensuring their final reproductive efforts were maximized by remating. This suggests that damaging females is a pleiotropic effect which inadvertently leads to increased, not decreased, polyandry.

RGD peptides and monoclonal antibodies, antagonists of alpha(v)-integrin, enter the cells by independent endocytic pathways

Cyclic synthetic peptides containing the arginine-glycine-aspartate motif (cRGD) and monoclonal antibodies (mAbs) targeted for individual integrins have been developed as potential therapeutic drugs for the treatment of several diseases. We showed that a cRGD peptide targeted for alpha(v)beta(3) was internalized in alpha(v)-integrin expressing and nonexpressing melanoma cells by an integrin independent fluid-phase endocytosis pathway that does not alter the number of functional integrin receptors at the cell surface. In contrast, a blocking mAb directed to alpha(v) was internalized by an integrin-dependent endocytosis pathway that reduced the number of functional integrin receptors at the cell surface. We prove that melanoma cells pretreated with the mAb do not readhere to the substrate, whereas cells pretreated with cRGD peptide retain their readhesion capacity. Given the growing importance of RGD peptides, knowledge of these cellular mechanisms is required to improve the development of antiangiogenic and anti-inflammatory drugs.

Solution structure of the Ras binding domain of the protein kinase Byr2 from Schizosaccharomyces pombe

BACKGROUND

After activation, small GTPases such as Ras transfer the incoming signal to effectors by specifically interacting with the binding domain of these proteins. Structural details of the binding domain of different effectors determine which pathway is predominantly activated. Byr2 from fission yeast is a functional homolog of Raf, which is the direct downstream target of Ras in mammalians that initiates a protein kinase cascade. The amino acid sequence of Byr2's Ras binding domain is only weakly related to that of Raf, and Byr2's three-dimensional structure is unknown.

RESULTS

We have solved the 3D structure of the Ras binding domain of Byr2 (Byr2RBD) from Schizosaccharomyces pombe in solution. The structure consists of three alpha helices and a mixed five-stranded beta pleated sheet arranged in the topology betabetaalphabetabetaalphabetaalpha with the first seven canonic secondary structure elements forming a ubiquitin superfold. 15N-(1)H-TROSY-HSQC spectroscopy of the complex of Byr2RBD with Ras*Mg(2+)*GppNHp reveals that the first and second beta strands and the first alpha helix of Byr2 are mainly involved in the protein-protein interaction as observed in other Ras binding domains. Although the putative interaction site of H-Ras from human and Ras1 from S. pombe are identical in sequence, binding to Byr2 leads to small but significant differences in the NMR spectra, indicating a slightly different binding mode.

CONCLUSIONS

The ubiquitin superfold appears to be the general structural motif for Ras binding domains even in cases with vanishing sequence identity. However, details of the 3D structure and the interacting interface are different, thereby determining the specifity of the recognition of Ras and Ras-related proteins.

Overcoming the problems associated with poor spectra quality of the protein kinase Byr2 using residual dipolar couplings

For the Ras-binding domain of the protein kinase Byr2, only a limited number of NOE contacts could be initially assigned unambiguously, as the quality of the NOESY spectra was too poor. However, the use of residual (1)H-(15)N dipolar couplings in the beginning of the structure determination process allows to overcome this problem. We used a three-step recipe for this procedure. A previously unknown structure could be calculated reasonably well with only a limited number of unambiguously assigned NOE contacts.

Activation of alpha(v)beta3-vitronectin binding is a multistage process in which increases in bond strength are dependent on Y747 and Y759 in the cytoplasmic domain of beta3

Integrin receptors serve as mechanical links between the cell and its structural environment. Using alpha(v)beta3 integrin expressed in K562 cells as a model system, the process by which the mechanical connection between alpha(v)beta3 and vitronectin develops was analyzed by measuring the resistance of these bonds to mechanical separation. Three distinct stages of activation, as defined by increases in the alpha(v)beta3-vitronectin binding strength, were defined by mutational, biochemical, and biomechanical analyses. Activation to the low binding strength stage 1 occurs through interaction with the vitronectin ligand and leads to the phosphorylation of Y747 in the beta3 subunit. Stage 2 is characterized by a 4-fold increase in binding strength and is dependent on stage1 and the phosphorylation of Y747. Stage 3 is characterized by a further 2.5-fold increase in binding strength and is dependent on stage 2 events and the availability of Y759 for interaction with cellular proteins. The Y747F mutant blocked the transition from stage 1 to stage 2, and the Y759F blocked the transition from stage 2 to stage 3. The data suggest a model for tension-induced activation of alpha(v)beta3 integrin.

Distinct ligand-binding modes for integrin alpha(v)beta(3)-mediated adhesion to fibronectin versus vitronectin

Cell surface integrins can adopt distinct conformations in response to ligand binding and intracellular signals. Several integrins including alpha(v)beta(3) can bind to multiple ligands. The binding of alpha(v)beta(3) to fibronectin and vitronectin was used as a model to determine whether the same or distinct forms of the receptor were utilized in strong binding to the two different ligands. A spinning-disc device was used to measure the relative strength of the alpha(v)beta(3)-ligand bonds. The initial binding reaction for both ligands occurred in the absence of metabolic energy and resulted in a strong adhesion to fibronectin but a weak adhesion to vitronectin. Increases in the strength of the alpha(v)beta(3)-vitronectin bond required phosphorylation of the beta(3) cytoplasmic domain, intracellular signals, and the binding of cytoskeletal proteins to cytoplasmic domains of beta(3) controlled by Tyr-747 and Tyr-759. In contrast, alpha(v)beta(3)-mediated adhesion to fibronectin was unaffected by phorbol 12-myristate 13-acetate, mutations of Tyr-747 and Tyr-759 to phenylalanine, or availability of metabolic energy. This suggests that strong adhesion to fibronectin used the initial binding conformation, whereas strong binding to vitronectin required signaling-induced changes in the conformation of alpha(v)beta(3).

Nematic liquid crystals with a tetrafluoroethylene bridge in the mesogenic core structure

A dramatic increase of the clearing temperatures of liquid crystals based on bis(cyclohexyl)ethane 1 by 50 to 70 K can be achieved by the perfluorination of the central ethylene link. Conformational analysis indicates that this effect is due to the increased rigidity of the mesogenic core structure and to the suppression of conformers with a bent shape. Materials based on bis(cylohexyl)tetrafluoroethane 2 might play a crucial role as materials for the next generation of active matrix LCDs with reduced power consumption.

Human dermal safety studies with eflornithine HCl 13.9% cream (Vaniqa), a novel treatment for excessive facial hair

Eflornithine HCl 13.9% cream (Vaniqa) is a novel treatment for the management of unwanted facial hair in women. This paper reports the results of four modified open-label, within-subject vehicle-controlled studies evaluating the dermal safety of this topical treatment. In a repeated insult patch test (230 subjects), erythema with oedema occurred in 38.9% of subjects treated with eflornithine HCl 13.9% cream and 4.8% of subjects treated with vehicle cream. Challenge applications at previously untested sites following the three-week induction period produced noticeable erythema or greater on only four sites treated with eflornithine HCl 13.9% cream and one vehicle-treated site. The erythema at these sites subsided substantially within 24 hours. In a three-week cumulative irritation study (30 subjects), the mean irritation score for sites treated with eflornithine HCl 13.9% cream was 1.33, compared with 0.76 at vehicle-treated sites and 3.09 at positive-control (sodium lauryl sulphate-treated) sites (p < 0.001 between all three groups). In a phototoxicity study (25 subjects), irradiated sites showed either no reaction (40% of both sites treated with eflornithine HCl 13.9% cream and vehicle-treated sites), or mild erythema subsiding in all cases but one within 24 hours. No reaction was seen at non-irradiated sites. In a photocontact allergy study (30 subjects), challenge with eflornithine HCl 13.9% cream or its vehicle alone produced either no reaction or mild erythema subsiding within 24 hours at both irradiated and non-irradiated sites. No serious adverse events were reported during the studies, and the only adverse events considered related to treatment were pruritus (three subjects) and dry skin at test site (one subject). These results demonstrate that eflornithine HCl 13.9% cream does not have contact sensitising, photocontact allergic or phototoxic properties. It can cause irritation under exaggerated conditions of use. Eflornithine HCl 13.9% cream, therefore, has a favourable dermal safety profile appropriate for a topical treatment to be applied routinely.

Evaluation of an instrumented walkway for measurement of the kinematic parameters of gait

The purpose of this study was to compare kinematic gait parameters measured with an instrumented walkway system (GAITRite(R)) and a video-based system (peak performance motus 3.1(R)). Subjects walked across a GAITRite mat with embedded pressure sensors. Reflective markers were attached to subjects' shoes and video capture was simultaneously performed during each trial. Video data were then digitized manually using peak software. Correlation coefficients for all parameters measured with both systems were high (>/=0.94). Significant differences between systems were found with analysis of variance (ANOVA) for two parameters, step length and stride velocity (P=0.003, 0.0002). The results of this study indicate that the instrumented walkway gave comparable results for temporal parameters but further investigation is needed to evaluate the fidelity of its spatial performance.

Force required to break alpha5beta1 integrin-fibronectin bonds in intact adherent cells is sensitive to integrin activation state

Binding of integrin receptors to extracellular ligands is a complex process involving receptor-ligand interactions at the cell-substrate interface, signals activating the receptors, and assembly of cytoskeletal and adhesion plaque proteins at the cytoplasmic face. To analyze the contribution of these elements to overall cell adhesion, we have developed a model system that characterizes the functional binding characteristic for adhesion receptors as the force required to separate the integrin-ligand bond. A spinning disk device was used to apply a range of controlled hydrodynamic forces to adherent cells. The adhesion of K562 erythroleukemia cells, a cell line expressing a single fibronectin receptor, integrin alpha5beta1, which was uniformly activated with the monoclonal antibody TS2/16, to defined fibronectin surface densities was examined. Cell adhesion strength increased linearly with receptor and ligand densities. Based on chemical equilibrium principles, it is shown that adhesion strength is directly proportional to the number of receptor-ligand bonds. This analysis provides for the definition of a new physical parameter, the adhesion constant psi, which is related to the bond strength and binding equilibrium constant and has units of force-length2. This parameter can be measured by the experimental system presented and is governed by the activation state of integrin receptors. This simplified model isolates the integrin receptor-ligand binding parameters and provides a basis for analysis of the functions of signaling and cytoskeletal elements in the adhesion process.

Double-blind trial of omeprazole and amoxicillin in the cure of Helicobacter pylori infection in gastric ulcer patients. The Ulcer Study Group, Germany

BACKGROUND

Our aim was to investigate the efficacy of omeprazole and amoxicillin in curing Helicobacter pylori infection in gastric ulcer patients.

METHODS

In a double-blind trial 185 H. pylori-positive gastric ulcer patients were prospectively randomized to receive 40 mg omeprazole twice daily and either 750 mg amoxicillin three times daily or 750 mg amoxicillin placebo three times daily on days 1-14, followed by 20 mg omeprazole daily on days 15-56.

RESULTS

Twenty-seven patients were excluded because of lack of compliance or missed follow-up examinations; one patient receiving amoxicillin discontinued treatment owing to side effects. On an intention-to-treat basis, omeprazole/amoxicillin led to cure of H. pylori infection in 67.1% (47 of 70) of patients not using non-steroidal anti-inflammatory drugs (NSAIDs)/aspirin (ASA) and in 46.7% (14 of 30) of those taking NSAIDs/ASA (P < 0.05). With the omeprazole/placebo regimen, H. pylori infection was cured in 8.8% (no NSAIDs), and 0% (NSAIDs).

CONCLUSIONS

The use of NSAIDs/ASA may limit the efficacy of omeprazole/amoxicillin in curing H. pylori infection in gastric ulcer patients.