CHE-14, a protein with a sterol-sensing domain, is required for apical sorting in C. elegans ectodermal epithelial cells.

BACKGROUND: Polarised trafficking of proteins is critical for normal expression of the epithelial phenotype, but its genetic control is not understood. The regulatory gene lin-26 is essential for normal epithelial differentiation in the nematode Caenorhabditis elegans. To identify potential effectors of lin-26, we characterised mutations that result in lin-26-like phenotypes. Here, we report the phenotypic and molecular analysis of one such mutant line, che-14. RESULTS: Mutations in che-14 resulted in several partially penetrant phenotypes affecting the function of most epithelial or epithelial-like cells of the ectoderm, including the hypodermis, excretory canal, vulva, rectum and several support cells. The defects were generally linked to the accumulation of vesicles or amorphous material near the apical surface, suggesting that secretion was defective. The CHE-14 protein showed similarity to proteins containing sterol-sensing domains, including Dispatched, Patched and NPC1. A fusion protein between full-length CHE-14 and the green fluorescent protein became localised to the apical surface of epithelial cells that require che-14 function. Deletions that removed the predicted transmembrane domains or extracellular loops of CHE-14 abolished apical localisation and function of the protein. CONCLUSIONS: We propose that CHE-14 is involved in a novel secretory pathway dedicated to the exocytosis of lipid-modified proteins at the apical surface of certain epithelial cells. Our data raise the possibility that the primordial function of proteins containing a sterol-sensing domain is to control vesicle trafficking: CHE-14 and Dispatched in exocytosis, Patched and NPC1 in endocytosis.

Epithelial biology: lessons from Caenorhabditis elegans.

Epithelial cells are essential and abundant in all multicellular animals where their dynamic cell shape changes orchestrate morphogenesis of the embryo and individual organs. Genetic analysis in the simple nematode Caenorhabditis elegans provides some clues to the mechanisms that are involved in specifying epithelial cell fates and in controlling specific epithelial processes such as junction assembly, trafficking or cell fusion and cell adhesion. Here we review recent findings concerning C. elegans epithelial cells, focusing in particular on epithelial polarity, and transcriptional control.

Electrical stimulation of anterior visual pathways in retinitis pigmentosa.

PURPOSE: To explore electrically induced phosphenes in blind patients with retinitis pigmentosa (RP) in comparison with healthy subjects and to develop a screening test for candidates for an optic nerve visual prosthesis implantation. METHODS: Phosphenes are obtained by charge balanced biphasic pulse stimulations through a surface cathode over the closed eyelids and an anode near the opposite ear. The resulting strength-duration relationship for somatosensory, phosphene, and pain threshold has been recorded in five RP patients as well as in 10 healthy volunteers. RESULTS: In sighted subjects, the average rheobase and chronaxy for phosphene perception are 0.28 mA and 3.07 msec, respectively. For pulse durations longer than 2 msec, phosphenes are usually obtained at current strengths below the level giving rise to any other electrically generated sensation. In RP patients, however, phosphenes are not so easily obtained. One in five had no visual response at all. Another patient reported a flash perception for the longest pulse durations only. Spontaneous phosphenes interfered heavily with the stimulation in a third person. Finally, despite the higher threshold, two patients displayed normally shaped strength-duration curves. CONCLUSIONS: The surface stimulation has proven harmless, adequate, and very helpful to ascertain that the optic nerve can be electrically activated in completely blind individuals. Long-duration stimulation pulses yield very low phosphene thresholds in healthy subjects. Anterior visual pathways activation requires higher currents in RP patients.

Visual sensations produced by optic nerve stimulation using an implanted self-sizing spiral cuff electrode.

A blind volunteer with retinitis pigmentosa was chronically implanted with a self-sizing spiral cuff electrode around an optic nerve. Electrical stimuli applied to the nerve produced localized visual sensations that were broadly distributed throughout the visual field and could be varied by changing the stimulating conditions. These results demonstrate the potential for constructing a visual prosthesis, based on electrical stimulation of the optic nerve, for blind subjects who have intact retinal ganglion cells.

Tuberculosis control and the private health sector in Bolivia: a survey of pharmacies.

BACKGROUND: Bolivia is a high tuberculosis (TB) incidence country with a large private for-profit health sector. TB drug sales in private pharmacies are not illegal. OBJECTIVES: To measure the availability of TB drugs in private pharmacies, study vendors' attitudes, and explore the potential for collaboration between the public health sector and pharmacies. METHODS: Simulated clients visited a random sample of 100 pharmacies in the city of Cochabamba, presenting with a prescription for four TB drugs. After the survey, contacts were made with the local Pharmacist's Association. RESULTS: Twenty-five pharmacies sold at least one drug, 23 sold rifampicin and 16 sold isoniazid. Of 99 pharmacies unable to fill the whole prescription, 59 referred the client to another pharmacy, and 22 to the public services. Pharmacists said that rifampicin was often prescribed for non-TB indications, and that TB drug sales were of minimal contribution to their income. They agreed to stop selling the drugs and to refer clients seeking them to the public sector. CONCLUSION: This study has documented a small market for TB drugs sales in private pharmacies and provided the opportunity to start collaboration with the pharmacists. Our results suggest that the private sector contributes little to managing TB in Bolivia.

[Breast cancer and its psychological approach: family, others, chance and...me]. / Le cancer du sein et son approche psychologique: la famille, les autres, la chance et ... moi.

Since several years already, the scientific literature evoked the psycho-oncological perspective in the psychotherapeutic treatment of the patient suffering of a malignant mammary pathology. The objective of this article is to insist on some characteristics of personality inherent to the individual that suffers of a malignant mammary pathology. Comparing three groups of women (malignant mammary pathology--n = 51, benign mammary pathology--n = 71 and a group controls--n = 30), a set of questionnaires relating to locus of control and to the close circle--family and couple--has been managed. Results indicate that the woman suffering of a breast cancer is less "intern", consider that her health depends on factor "luck" and wish less cohesion and therefore more of distance within her couple and her family.

A role for Rab10 in von Willebrand factor release discovered by an AP-1 interactor screen in C. elegans.

BACKGROUND: Endothelial von Willebrand factor (VWF) mediates platelet adhesion and acts as a protective chaperone to clotting factor VIII. Rapid release of highly multimerized VWF is particularly effective in promoting hemostasis. To produce this protein, an elaborate biogenesis is required, culminating at the trans-Golgi network (TGN) in storage within secretory granules called Weibel-Palade bodies (WPB). Failure to correctly form these organelles can lead to uncontrolled secretion of low-molecular-weight multimers of VWF. The TGN-associated adaptor AP-1 and its interactors clathrin, aftiphilin and γ-synergin are essential to initial WPB formation at the Golgi apparatus, and thus to VWF storage and secretion. OBJECTIVES: To identify new proteins implicated in VWF storage and/or secretion. METHODS: A genomewide RNA interference (RNAi) screen was performed in the Nematode C. elegans to identify new AP-1 genetic interactors. RESULTS: The small GTPase Rab10 was found to genetically interact with a partial loss of function of AP-1 in C. elegans. We investigated Rab10 in human primary umbilical vein endothelial cells (HUVECs). We report that Rab10 is enriched at the Golgi apparatus, where WPB are formed, and that in cells where Rab10 expression has been suppressed by siRNA, VWF secretion is altered: the amount of rapidly released VWF was significantly reduced. We also found that Rab8A has a similar function. CONCLUSION: Rab10 and Rab8A are new cytoplasmic factors implicated in WPB biogenesis that play a role in generating granules that can rapidly respond to secretagogue.

Collaboration between private pharmacies and national tuberculosis programme: an intervention in Bolivia.

BACKGROUND: Public-private partnerships are felt to be necessary for tuberculosis (TB) control in some developing countries. OBJECTIVES: To evaluate the potential of a collaboration between the National TB Programme (NTP) and private pharmacies in Bolivia, the country with the highest TB incidence in Latin America. METHODS: We contacted the local Pharmacists' Association in the city of Cochabamba, and designed a two phase intervention. The objectives of the first phase were to decrease the availability of TB drugs in private pharmacies on a voluntary basis, and to improve referral of clients seeking TB drugs to the NTP. A survey of all pharmacies allowed for a before-after comparison with a baseline survey. The objectives of the second phase were to obtain referral of pharmacy clients with chronic cough for TB screening in the NTP. This phase was started in 70 pharmacies and evaluated after 2 months using the referral slips issued by the pharmacists. RESULTS: The proportion of pharmacies selling TB drugs decreased (rifampicin: 23-11.5%; isoniazid: 16-3.1%; P<0.001) and the proportion of pharmacies referring to the NTP clients seeking TB drugs increased (22-58%; P<0.0001). In the second phase, 26 of 70 pharmacies (38%) referred a total of 41 clients for screening in the NTP (i.e. an average of 0.29 clients per pharmacy and per month); 11 of 41 (27%) were screened and three of 11 (27%) diagnosed with smear-positive TB. CONCLUSION: The first phase of the intervention proved effective in reducing the availability of the main TB drugs in pharmacies, and in improving referral of clients seeking TB drugs. Key factors in this success were not specific to Bolivia, and collaboration between private pharmacies and public services appears possible in that respect. However, collaboration with pharmacies does not seem an efficient way to increase the number of patients screened for TB, and to shorten delays to TB diagnosis and treatment.

Delays to treatment and out-of-pocket medical expenditure for tuberculosis patients, in an urban area of South America.

Short delays to treatment are important for the control of tuberculosis (TB). National Tuberculosis Programmes provide free diagnosis and treatment for smear-positive patients, so that the patients' out-of-pocket medical expenditure could be almost nil. The factors associated with delays in starting treatment, and the pre-treatment out-of-pocket medical expenditure for TB patients, have now been investigated in the Bolivian city of Cochabamba. Bolivia is the Latin American country with the highest incidence of TB. It is covered by a national TB programme that provides free diagnosis and free treatment for smear-positive patients. Structured interviews with 144 smear-positive patients enrolled in this programme revealed median patient, provider and total delays of 3.6, 6.2 and 12.9 weeks, respectively. The total delays were longer for the female patients than for the male, and for patients who consulted private doctors than for the other patients. When the first healthcare provider was a doctor, the median provider delay was 4.9 weeks in the public sector but 7.2 weeks in the private. The median out-of-pocket medical expenditure per patient, which was U.S.$13.2 overall, was much higher for those who consulted a private doctor than for those who did not (U.S.$21.9 v. U.S.$5.4, respectively; P<0.001). It appears that interventions targeting doctors (in both the private and public sectors) are likely to have a larger impact on the shortening of delays in TB treatment than interventions targeting patients. They could also reduce unnecessary out-of-pocket expenditure.

[Rationale in implant prosthetics]. / A propos de la logique en prothese implantaire.

Today, it is quite easy, even to the unfamiliar practitioner in implantology, to get clear ideas of the surgical stage in treatments where implants are involved. These procedures have been well described and documented, especially by the swedish school. But things are less simple concerning the prosthetical procedures. After a personal experience of years, in this field, both, as oral surgeon and prosthodontist, we think time has come to point out several criterias, leading to long range success. We will review some major aspects of this particular prosthodontics, like: different clinical situations, according to the localisation of edentulism, connections, frameworks and cosmetics, and so on... We are convinced that the respect of these rules is one of the numerous keys of success in today's implantology.

The Caenorhabditis elegans gene lin-26 can trigger epithelial differentiation without conferring tissue specificity.

How epithelial cell fates become specified is poorly understood. We have previously shown that the putative C2H2 zinc-finger transcription factor LIN-26 is required for the differentiation of ectodermal and mesodermal epithelial cells in Caenorhabditis elegans. Here, we report that ectopic LIN-26 expression during early gastrulation transforms most blastomeres into epithelial-like cells. Specifically, LIN-26 induced the expression of three epithelial markers: the adherens junction protein JAM-1; DLG-1, which is essential for the assembly of JAM-1 at junctions; and CHE-14, which is involved in apical trafficking. Furthermore, ultrastructural studies revealed that ectopic LIN-26 expression induced the formation of adherens-like junctions. However, ectopic lin-26 expression did not confer any tissue-specific cell fate, such as the epidermal cell fate, as evidenced from the observation that several epidermal-specific genes were not induced. Conversely, we show that epidermal cells displayed some polarity defects in lin-26 mutants. We conclude that lin-26 can induce epithelial differentiation and that epitheliogenesis is not a default pathway in C. elegans.

Sequence and analysis of a 26.9 kb fragment from chromosome XV of the yeast Saccharomyces cerevisiae.

We have determined the nucleotide sequence of a fragment of chromosome XV of Saccharomyces cerevisiae cloned into cosmid pEOA048. The analysis of the 26,857 bp sequence reveals the presence of 19 open reading frames (ORFs), and of one RNA-coding gene (SNR17A). Six ORFs correspond to previously known genes (MKK1/SSP32, YGE1/GRPE/MGE1, KIN4/KIN31/KIN3, RPL37B, DFR1 and HES1, respectively), all others were discovered in this work. Only five of the new ORFs have significant homologs in public databases, the remaining eight correspond to orphans (two of them are questionable). O5248 is a probable folypolyglutamate synthetase, having two structural homologs already sequenced in the yeast genome. O5273 shows homology with a yeast protein required for vanadate resistance. O5268 shows homology with putative oxidoreductases of different organisms. O5257 shows homology with the SAS2 protein and another hypothetical protein from yeast. The last one, O5245, shows homology with a putative protein of Caenorhabditis elegans of unknown function. The present sequence corresponds to coordinates 772,331 to 799,187 of the entire chromosome XV sequence which can be retrieved by anonymous ftp (ftp. mips. embnet. org).

The microsystems based visual prosthesis for optic nerve stimulation.

The microsystems based visual prosthesis (MiViP) visual prosthesis generates visual perceptions well below safety and stimulator saturation limits. These perceptions, called phosphenes, are of reasonably small size and are broadly distributed in the visual field. They can thus be used to convey useful visual information. Psychophysical evaluations are being performed in order to assess the implantee's benefits in the use of the MiViP optic nerve visual prosthesis. In a pattern-recognition task, the performance improved regularly with practice with an increasing score and a decreasing delay to recognition. These observations open the way toward an evaluation of general mobility improvement with the portable system. In conclusion, the results obtained so far still support the potential usefulness of the optic nerve visual prosthesis. A low-resolution artificial vision can be expected from the prosthesis after extensive training.