A collagen peptide motif activates tyrosine kinase-dependent calcium signalling pathways in human osteoblast-like cells

A collagen peptide motif (DGEA) which is a putative alpha 2 beta 1 integrin binding site was examined for its ability to activate Ca2+ signalling pathways in the human osteoblast-like cell line SaOS-2. We show that these cells express both alpha 2 beta 1 integrin subunits (by immunocytochemistry) and that an anti-beta 1 monoclonal antibody (DF5) mobilizes Ca2+ in these cells. DGEA elevated intracellular Ca2+ in fura-2-loaded cells, in a concentration- and sequence-dependent fashion, with an EC50 of 250 microM. The tyrosine kinase inhibitor herbimycin A reduced the number of cells responding to DGEA and to transforming growth factor alpha. Thrombin also stimulated a rise in intracellular Ca2+, but the number of cells responding was not reduced by herbimycin A. The DGEA response was dependent on extracellular Ca2+, but was not due to Ca2+ influx, since it was blocked by thapsigargin and not by lanthanum. Using three different anti-alpha 2 monoclonal antibodies, we were unable to show that the DGEA-induced Ca2+ signal was mediated by the alpha 2 beta 1 integrin. In summary, the DGEA collagen motif does appear to activate receptor-mediated Ca2+ signalling events in SaOS-2 cells, in a divalent cation-dependent manner, but we were unable to demonstrate a role for alpha 2 beta 1 integrin in this response.     

Analysis of Salmonella serovars in Taiwan by the phase induction method

Major strides in the molecular biology of essential hypertension are currently underway. This has tended to obscure the fact that a number of inherited disorders associated with low blood pressure exist and that these diseases may have milder and underrecognized phenotypes that contribute importantly to blood pressure variation in the general population. This review highlights some of the gene products that, if abnormal, could cause hypotension in some individuals. Diseases due to abnormalities in the catecholamine enzymes are discussed in detail. It is likely that genetic abnormalities with hypotensive phenotypes will be as interesting and diverse as those that give rise to hypertensive disorders.     

Herpes labialis in skiers: randomized clinical trial of acyclovir cream versus placebo

Five cases of prenatally detected neck masses that had a potential for airway obstruction at birth are described. The various options for management of the airway are discussed, including using maternal-fetal circulation until intubation, rigid bronchoscopy, tracheotomy, cyst aspiration, or extracorporeal membrane oxygen support. Congenital abnormalities involving the fetal face or neck are extremely rare. With technical advances in ultrasonography, these masses were first noted on prenatal ultrasound in the late 1970s. Before that period, they were detected at delivery. These masses are solid or cystic and may cause asphyxia because of airway obstruction at the time of delivery. The survivability of these neonates without immediate intervention at birth is 0% to 20%. If a neck mass is detected in the fetus by prenatal ultrasonography, then a strategic plan for these types of cases should be developed early in the prenatal period. The airway management plan should be tailored for each individual case. Coordination and the expertise of an obstetrician, neonatologist, anesthesiologist, and pediatric otolaryngologist are needed to manage these complex situations.     

Clinician-educators in academic medical centers: a two-part challenge

Between 1967 and 1996, > 18,700 strains of Yersinia species, excluding Yersinia pestis, were recovered in Belgium from a variety of gastrointestinal and extraintestinal sites in patients. Full identification and serotyping were performed by the two Belgian reference laboratories. Yersinia enterocolitica serogroup O:3 predominated (79.4% of strains), followed by serogroup O:9 (11.1%). The remaining 9.5% of isolates belonged to serogroups and related species generally considered nonpathogenic. Acute enterocolitis was the most common clinical form of Y. enterocolitica infection, affecting primarily children younger than 5 years of age. Since 1967, there was a steady increase in isolations every year, with 305 cases in 1975 and up to 1,469 in 1986. From 1987 on, there was a clear decrease in the number of reported cases, although the number of participating laboratories and culture techniques remained constant. This significant decrease in the occurrence of Y. enterocolitica infections may be explained by changes in the slaughtering procedures and eating habits of the population.     

The 40-kDa subunit of DNA fragmentation factor induces DNA fragmentation and chromatin condensation during apoptosis

We report here the reconstitution of a pathway that leads to the apoptotic changes in nuclei by using recombinant DNA fragmentation factor (DFF), a heterodimeric protein of 40 and 45 kDa. Coexpression of DFF40 and DFF45 is required to generate recombinant DFF, which becomes activated when DFF45 is cleaved by caspase-3. The cleaved fragments of DFF45 dissociate from the DFF40, the active component of DFF. Purified DFF40 exhibited an intrinsic DNase activity that was markedly stimulated by chromatin-associated proteins histone H1 and high mobility group proteins. DFF40 also triggered chromatin condensation when incubated with nuclei. These data suggest that DFF40 is sufficient to trigger both DNA fragmentation and chromatin condensation during apoptosis.     

Phytotoxicity and cytotoxicity of the fumonisin C and P series of mycotoxins from Fusarium spp. fungi

Fumonisin C (FC) and P (FP) are two recently identified series of sphingosine-analog mycotoxins, for which biological activities have not previously been reported. FC1, FC2 and OH-FC1 (1 microM) exhibited strong phytotoxicity comparable to the standard FB1 in duckweed (Lemna pausicotata L.) cultures, whereas FC3 and FC4 were moderately phytotoxic. Conversely, FP1 exhibited weak phytotoxicity only at higher concentrations (> or =10 microM). These mycotoxins exhibited a similar pattern of cytotoxicity with FB1-sensitive cultured mammalian cell lines, H4TG and MDCK.     

Use of abdominal computed tomography for identifying disseminated fungal infection in pediatric cancer patients

Disseminated fungal infection (DFI) is an important cause of morbidity and mortality among immunosuppressed patients with cancer. To determine the role of abdominal computed tomography (CT) in the diagnosis and management of DFI, we studied the records of patients treated in a pediatric oncology center over an 11-year period. A total of 35 children had CT findings compatible with fungal abscesses in the liver, spleen, and/or kidneys and had fungal infection confirmed by culture, biopsy, or at autopsy. Patients were treated with antifungal agents (median duration of treatment, 57 days) until fever resolved and repeated CT scans demonstrated that the lesions had disappeared, regressed, or stabilized. The 3-month survival rate was 86%. An additional 29 patients with similar characteristics and risk factors had characteristic CT findings, but DFI was not documented with other procedures. These patients were empirically treated for presumed DFI; their courses and outcomes were similar to those for patients with documented DFI. These results suggest that it is reasonable to make a presumptive diagnosis of DFI for patients with characteristic CT findings and clinical features. With appropriate therapy, the prognosis for pediatric patients with cancer and documented or presumed DFI is good.     

Mechanical properties of titanium connectors

The tensile mechanical properties of welded titanium joints were studied, and intact titanium was used as controls. Welded joints were fabricated with either a stereographic laser-welding technique or a gas tungsten arc welding technique. The effect of heat treatment following a simulated porcelain application was also investigated. Heat-treated laser welds had significantly lower ultimate tensile strengths. Heat treatment had no effect on the modulus of elasticity or elongation, but generally significantly decreased the yield strength of the titanium specimens. The gas tungsten are welding specimens had significantly higher yield strengths and elastic moduli than the other two groups. The elongation of the control specimens was significantly greater than the elongation of the gas tungsten arc welding specimens, which was in turn significantly higher than that of the laser-welded specimens.