Gbeta gamma-independent coupling of alpha2-adrenergic receptor to p21(rhoA) in preadipocytes

In preadipocytes, alpha2-adrenergic receptor (alpha2-AR) stimulation leads to a Gi/Go-dependent rearrangement of actin cytoskeleton. This is characterized by a rapid cell spreading, the formation of actin stress fibers, and the increase in tyrosyl phosphorylation of the focal adhesion kinase (pp125(FAK)). These cellular events being tightly controlled by the small GTPase p21(rhoA), the existence of a Gi/Go-dependent coupling of alpha2-AR to p21(rhoA) in preadipocytes was proposed. In alpha2AF2 preadipocytes (a cell clone derived from the 3T3F442A preadipose cell line and which stably expresses the human alpha2C10-adrenergic receptor) alpha2-adrenergic-dependent induction of cell spreading, formation of actin stress fibers, and increase in tyrosyl phosphorylation of pp125(FAK) were abolished by pretreatment of the preadipocytes with the C3 exoenzyme, a toxin which impairs p21(rhoA) activity by ADP-ribosylation. Conversely, C3 exoenzyme had no effect on the alpha2-adrenergic-dependent increase in tyrosyl phosphorylation and shift of ERK2 mitogen-activated protein kinase. alpha2-Adrenergic stimulation also led to an increase in GDP/GTP exchange on p21(rhoA), as well as to an increase in the amount of p21(rhoA) in the particulate fraction of alpha2AF2 preadipocytes. Stable transfection of alpha2AF2 preadipocytes with the COOH-terminal domain of betaARK1 (betaARK-CT) (a blocker of Gbeta gamma-action), strongly inhibited the alpha2-adrenergic-dependent increase in tyrosyl phos- phorylation and shift of ERK2, without modification of the tyrosyl phosphorylation of pp125(FAK) and spreading of preadipocytes. These results show that alpha2-adrenergic-dependent reorganization of actin cytoskeleton requires the activation of p21(rhoA) in preadipocytes. Conversely to the activation of the p21(ras)/mitogen-activated protein kinase pathway, the alpha2-adrenergic activation of p21(rhoA)-dependent pathways are independent of the beta gamma-subunits of heterotrimeric G proteins.     

The ORF47 and ORF66 putative protein kinases of varicella-zoster virus determine tropism for human T cells and skin in the SCID-hu mouse

The varicella-zoster virus (VZV) genes ORF47 and ORF66 are predicted to encode serine/threonine protein kinases, which are homologs of herpes simplex virus 1 (HSV-1) UL13, and US3. When mutants were constructed by inserting stop codons into ORF47 and ORF66, the recombinants ROka47S and ROka66S, as well as intact ROka replicated in tissue culture. In contrast, inoculation of human thymus/liver or skin implants in SCID-hu mice showed that ORF47 protein was required for viral growth in human T cells and skin. Eliminating ORF66 expression inhibited VZV infectivity for T cells partially but did not impair replication in skin compared with ROka. Infectivity for T cells and skin was restored when ROka47S virus was complemented by insertion of ORF47 into a distant, noncoding site. The ORF47 gene product is the first VZV protein identified as necessary for T cell tropism. It also is essential for skin infectivity in vivo, as is glycoprotein C. Expression of ORF66 did not compensate for the absence of the ORF47 protein. The requirement for ORF47 expression in T cells and skin indicates that this gene product, which is dispensable in vitro, has a critical role within differentiated cells that are essential targets for VZV pathogenesis in vivo.     

Langerhans cells in Langerhans cell granulomatosis are not actively proliferating cells

Pulmonary Langerhans cell granulomatosis (LCG), also called histiocytosis X, is a disorder of unknown etiology characterized by the presence of destructive granulomas containing numerous Langerhans cells (LCs). The process may be localized or multifocal, and it remains unclear whether the same pathogenic mechanism is involved in all forms of the disease. It is often assumed that the massive accumulation of LCs at the sites of the lesions results from the abnormal proliferation of these cells, although it has been suggested that LCG in adults, at least in the lung, could be a reactive disorder initiated by activated LCs. Little is known, however, concerning the mechanisms responsible for the accumulation of large numbers of LCs in the course of the disease, and the relative contribution of recruitment and local proliferation of these cells remains to be established. To investigate this question, the proportion of replicating LCs was evaluated in biopsied granulomas from patients with localized or diffuse form of LCG by means of several histopathological techniques currently used in assessment of cell proliferation. The findings demonstrate that, except for proliferating cell nuclear antigen (PCNA), all parameters measured are low in all forms of the disease. They are similar to those of renewing epithelial cells and clearly less than those of neoplastic cells. These data strongly suggest that LCs in LCG granulomas are not a rapidly dividing cell population and that local LC replication makes only a minimal contribution to granuloma maintenance. Caution appears to be necessary in the use of PCNA as a marker of growth fraction.     

Inline skating, an old sport, newly discovered: harmless or a potential danger with socioeconomic effects?]

Over a period of one year, all accidents associated with in-line skating (ILS) were surveyed. Sport-specific data was recorded with a standardized questionnaire. The study comprised 66 patients with 75 injuries (48 upper limb, 16 skull, eight lower limb, three trunk). We were looking after 42 male and 24 female patients with an average age of 20 years (5-53 years). Twenty-seven patients (40%) had to be treated as inpatients. Overall, the most frequent injury (one third of all injuries) was forearm fracture close to the wrist (21 radius fractures, four radioulnar fractures). It had to be reset in 20 cases. Additional internal fixation was required in 10 cases (Kirschner wire osteosynthesis, intramedullary nailing or plate osteosynthesis). Only five patients could be treated with plaster cast fixation alone. Most patients with injuries in the vicinity of the wrist were not wearing a wrist protector at the time of the accident. The most frequent reasons given for not wearing protectors was forgetfulness or the high price of protectors. However, there were also two distal radius fractures and a disc injury in the wrist in patients who had been wearing wrist protectors. In most cases, ILS accidents lead to appreciable damage requiring a healing period of several weeks to months (average period of loss of work 41 days). The bfu (advisory center for accident prevention) reckons with 60,000 ILS cases annually in Switzerland. These injuries are thus of great socioeconomic importance. In the future, better risk behavior must be achieved by informing the population (wearing protectors, especially for the wrist and head, attendance of training courses).     

Partial sequencing of hog cholera virus Alfort strain genome and its comparison with other pestivirus strains

After molecular RNA cloning of the Alfort strain (Alfort/LCRV) of hog cholera virus (HCV), the nucleotide sequence of about 70% of the total genome was determined. This sequence was compared with homologous parts of previously published pestivirus genomes. The average homology with another clone of the Alfort strain (Alfort/FRC) was found to be lower (86.1%) than with Brescia strain of HCV (94.3%), while, compared with NADL, Osloss and SD-1 (3 different strains of bovine viral diarrhea virus, BVDV), the average homology was 67%. Although the amino-acid sequences show a higher degree of conservation, they had a similar degree of homology (92.7, 96.7, 69, 68.2 and 69%, respectively). Partial sequence comparison also revealed that Alfort/LCRV strain was more closely related to Alfort 187 (98.6% for the nucleotides and amino acids) and Weybridge (97.3% for the nucleotides and 96.1% for the amino acids) strains of HCV than it was to Alfort/FRC. These results may indicate that the Alfort/FRC strain has undergone more genomic variations during its historical passage. Genomic relationships among the pestiviruses are discussed.     

Treatments of hysteria

Treatment of hysteria requires establishing a management strategy. The first steps consist of symptomatic treatment (catharsis, counter-suggestion, hypnosis, narco-analysis, relaxation, focused psychoanalytical psychotherapy, drug therapy). Thereafter, an approach aiming to modify the psychic structure of the patient can be considered (supportive psychotherapy, psychoanalysis). Occasionally, a systemic approach is necessary. Although each facet of the treatment must be conducted by a specialist, one physician must supervise the overall strategy; this role falls naturally to the family doctor.     

Physical mechanisms involved in the genesis of temporomandibular joint sounds

Several different mechanisms are potentially capable of generating sounds in the temporomandibular joint (TMJ). These include impact, sliding and stick-slip friction, fluid dynamic effects and the release of elastic strain energy. It is the aim of this paper to provide a framework with which to separate sounds resulting from the different underlying causes. Each mechanism is described and its relevance to TMJ sounds and clinical significance discussed. Since it is not possible to observe these mechanisms in vivo the arguments are based mainly on analogies which are used to make predictions of the characteristic acoustic signatures of the sounds produced by these different mechanisms. In particular the changes in the characteristics of the sounds as parameters such as mandibular speed and loading are stressed. It is suggested that single short duration sounds (clicks) are due to impact, multiple short duration sounds (creaks) to stick-slip friction and defects of form and long duration sounds (crepitus) to simple sliding friction. Several other mechanisms which have no obvious clinical significance but which are capable of producing similar sounds are also described and methods of distinguishing them from the sounds that do have clinical implications are discussed.     

Splenorenal shunt blood flow by transit-time ultrasound as an index of collateral circulation in portal hypertensive rats

OBJECTIVE: The purpose of this study was to explore the role of sonography for women with urethral symptoms and a suspected urethral diverticulum. SUBJECTS AND METHODS: Nineteen women with urethral symptoms underwent voiding cystourethrography (VCUG) and transvaginal, transperineal, and urethral sonography (using a catheter-based transducer). VCUGs and sonograms were evaluated for diverticula, defined on sonography by direct visualization of the neck connecting the periurethral sac with the urethral lumen. The diverticular neck, size, location, and shape were noted. Lesions revealed by sonography as not connected to the urethra were also noted. RESULTS: Of 19 women, 14 had urethral diverticula and one had two diverticula, for a total of 15 diverticula. On sonography the diverticula ranged in diameter from 2 mm to 5 cm. Both sonography and VCUG showed 13 of the 15 diverticula. In addition, sonography revealed two infected periurethral cysts, a periurethral leiomyoma, a diffuse urethritis, and scarring or deformity of one patient's urethra from a prior diverticulectomy. On sonography, eight of the 13 diverticula wrapped around more than 50% of the urethral circumference. The neck was precisely seen (by definition) in 13 of 15 diverticula on sonography and in two of 13 diverticula on VCUG. CONCLUSION: Sonography is useful in this group of women with urethral symptoms and suspected urethral diverticula. It provides information on the extent and location of the diverticular neck, both of which are important in surgical excision. Also, sonography provides information on lesions not connected to the urethra. Sonography may prove useful in a broader group of women with urethral symptomatology.     

Conformationally constrained inhibitors of caspase-1 (interleukin-1 beta converting enzyme) and of the human CED-3 homologue caspase-3 (CPP32, apopain)

A systematic study of interleukin-1 beta converting enzyme (ICE, caspase-1) and caspase-3 (CPP32, apopain) inhibitors incorporating a P2-P3 conformationally constrained dipeptide mimetic is reported. Depending on the nature of the P4 substituent, highly selective inhibitors of both Csp-1 or Csp-3 were obtained.