Large vesicle extrusions from C. elegans neurons are consumed and stimulated by glial-like phagocytosis activity of the neighboring cell

Caenorhabditis elegans neurons under stress can produce giant vesicles, several microns in diameter, called exophers. Current models suggest that exophers are neuroprotective, providing a mechanism for stressed neurons to eject toxic protein aggregates and organelles. However, little is known of the fate of the exopher once it leaves the neuron. We found that exophers produced by mechanosensory neurons in C. elegans are engulfed by surrounding hypodermal skin cells and are then broken up into numerous smaller vesicles that acquire hypodermal phagosome maturation markers, with vesicular contents gradually degraded by hypodermal lysosomes. Consistent with the hypodermis acting as an exopher phagocyte, we found that exopher removal requires hypodermal actin and Arp2/3, and the hypodermal plasma membrane adjacent to newly formed exophers accumulates dynamic F-actin during budding. Efficient fission of engulfed exopher-phagosomes to produce smaller vesicles and degrade their contents requires phagosome maturation factors SAND-1/Mon1, GTPase RAB-35, the CNT-1 ARF-GAP, and microtubule motor-associated GTPase ARL-8, suggesting a close coupling of phagosome fission and phagosome maturation. Lysosome activity was required to degrade exopher contents in the hypodermis but not for exopher-phagosome resolution into smaller vesicles. Importantly, we found that GTPase ARF-6 and effector SEC-10/exocyst activity in the hypodermis, along with the CED-1 phagocytic receptor, is required for efficient production of exophers by the neuron. Our results indicate that the neuron requires specific interaction with the phagocyte for an efficient exopher response, a mechanistic feature potentially conserved with mammalian exophergenesis, and similar to neuronal pruning by phagocytic glia that influences neurodegenerative disease.

A randomised pilot study to assess the efficacy of an interactive, multimedia tool of cognitive stimulation in Alzheimer's disease

OBJECTIVE

To determine the usefulness of an interactive multimedia internet-based system (IMIS) for the cognitive stimulation of Alzheimer's disease.

METHODS

This is a 24-week, single-blind, randomised pilot study conducted on 46 mildly impaired patients suspected of having Alzheimer's disease receiving stable treatment with cholinesterase inhibitors (ChEIs). The patients were divided into three groups: (1) those who received 3 weekly, 20-min sessions of IMIS in addition to 8 h/day of an integrated psychostimulation program (IPP); (2) those who received only IPP sessions; and (3) those who received only ChEI treatment. The primary outcome measure was the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog). Secondary outcome measures were: Mini-Mental State Examination (MMSE), Syndrom Kurztest, Boston Naming Test, Verbal Fluency, and the Rivermead Behavioral Memory Test story recall subtest.

RESULTS

After 12 weeks, the patients treated with both IMIS and IPP had improved outcome scores on the ADAS-Cog and MMSE, which was maintained through 24 weeks of follow-up. The patients treated with IPP alone had better outcome than those treated with ChEIs alone, but the effects were attenuated after 24 weeks. All patients had improved scores in all of the IMIS individual tasks, attaining higher levels of difficulty in all cases.

CONCLUSION

Although both the IPP and IMIS improved cognition in patients with Alzheimer's disease, the IMIS program provided an improvement above and beyond that seen with IPP alone, which lasted for 24 weeks.

[Melatonin therapeutic use in psychiatry: a 39 year bibliographic study]

INTRODUCTION

The therapeutic uses of melatonin in psychiatry are reviewed.

METHODS

Data source and search strategy: a 39 year period search covering a 39 year period (1966-2004) was carried out using Medline data base. The search strategy consisted in the combination of the key words ((mental disorders or psychiatry)) and ((melatonin and therapeutic use)). Two restrictive criteria were applied: a) selection of studies carried out in humans, and b) only randomized controlled trials were admitted

RESULTS

56 articles were found. Twelve were excluded because they were not directly related to the study aim. Melatonin was used in 44 articles related to different clinical conditions. It was used because of its hypnotic and/or resynchronizing actions in 93.2 % of the articles, while in 4.5 % of the articles melatonin was used due to its antioxidant properties.

CONCLUSIONS

The main use of melatonin as a therapeutic agent in psychiatry is in sleep disorders and its use in other psychiatric is minor.

A clinical trial on the prevention of catheter-related sepsis using a new hub model

BACKGROUND

Catheter hub contamination is being increasingly recognized as a source of catheter-related sepsis. The authors have investigated the efficacy of a new hub design in preventing endoluminal catheter contamination and catheter-related sepsis arising at the hub.

METHODS

Adult surgical and intensive care patients requiring a subclavian catheter for at least 1 week were randomly assigned to receive catheters with standard connectors (control group, n=73) or equipped with a new hub model (new hub group, n=78). Skin, catheter tip, and hub cultures were performed at the time the catheter was withdrawn because therapy was terminated or because of suspicion of sepsis, in which case peripheral blood cultures were taken.

RESULTS

Of the 151 patients included, 15 (10%) developed catheter-related sepsis. Catheters were more often withdrawn because suspicion of infection in the control group (42 vs. 19%, p<0.005). Catheter sepsis rate was higher in the control group (16 vs. 4%, p<0.01) because of the low rate of catheter sepsis arising at the hub observed in the new hub group (1 vs. 11%, p<0.01). The prevalence of culture-positive catheter hubs without associated bacteremia (colonization) was higher in the control group (18 vs. 5%, P<0.03).

CONCLUSIONS

A new catheter hub has proved to be useful in preventing endoluminal bacterial colonization and catheter-related sepsis in subclavian lines inserted for a mean of 2 weeks.

[Reactivity to stress as a modular factor in psychopathology]

The relationship between Stress Reactivity and psychopathology, mainly minor psychopathology, in a sample of medical students (n = 76) to whom the Stress Reactivity Questionnaire (CRE-32) and Derogatis' SCL-90-R Questionnaire (Symptom Checklist 90 Revised) were administered, is studied. A higher psychopathological distress, as evidenced in SCL-90-R general psychopathological indexes and psychopathological dimensions scores, is reported by subjects with high stress reactivity compared to those with low stress reactivity (p < 0.001). These results suggest that stress reactivity acts as a buffer of psychopathology. Thus, the assumption of the participation of a "high stress reactivity" in facilitating illness in general, both in psychiatric conditions as in medical ones, is discussed.

[Diagnosis of dementia in primary care]

We studied the level of knowledge that a group of general practitioners (N = 40), selected by means of conglomerate sampling, had about dementias. To perform this study we used a five-question open questionnaire. Our conclusions were: 1) In our sample, 80% of the GP's were not familiar with the initial symptoms of dementia; 2) The full clinical picture of dementia was well recognized; 3) There was little knowledge about the management of a possible case of dementia, the most usual procedure being to remit it to a specialist; 4) In general, they did not know what the possible causes for dementia are, arteriosclerosis being the most frequently mentioned; 5) A considerable number of doctors (40%) believed dementia to be curable.

Priapism and neuroleptics: a case report

We present a case of priapism caused by the alpha adrenoreceptor blocking action of a butyrophenone. The problem was solved surgically performing a cavernousspongiosum fistula.

Comparative studies on naturally occurring antikeratin antibodies in human sera

Comparative studies on the specificity of the so-called antiepidermal antibodies (Abs) found in human sera were performed by immunoblotting, enzyme-linked immunosorbent assay (ELISA), and immunoelectron microscopy (IEM). After a screening test by indirect immunofluorescence (IF), sera obtained from patients with various diseases and controls could be classified in 5 different groups according to the IF patterns on the epidermis: sera reactive with: (1) the stratum corneum (SC); (2) the upper layer (U-Cyt); (3) the whole epidermis (G-Cyt); (4) basal cells (B-Cyt); and (5) negative ones. By immunoblotting, all the 23 IF-positive sera were found to bind to one or more keratin bands, and did not show any reactivity with epidermal Nonidet P-40 soluble proteins. SC-Abs were mainly directed against a 67 kD Keratin band, whereas U-Cyt- and G-Cyt-Abs bound to both 58-56 kD and 67-63 kD keratins. B-Cyt-Abs reacted strongly with 63 kD Keratins and slightly with a 50 kD band. Antikeratin Abs were detected by immunoblotting even in the IF-negative sera. The ELISA study showed that sera with high IF titers contained high levels of antikeratin Abs. In the IEM study using sera containing U-Cyt- or B-Cyt-Abs, 2 distinct reaction patterns were demonstrated: U-Cyt-Abs stained tonofilaments of suprabasal keratinocytes, while B-Cyt-Abs characteristically reacted with those of basal cells. Moreover, SC-, U-Cyt-, and G-Cyt-Abs were absorbed out by insoluble epidermal proteins, and B-Cyt-Abs were decreased in titer after the absorption test. The present study provides strong evidence that most, though not all, human antiepidermal Abs are directed against different keratin polypeptides, and that antikeratin Abs commonly occur in almost all human sera.