Interleukin-4 and tumour necrosis factor-alpha produce non isotype specific partial differentiation of peripheral blood B-cells in myeloma

In a previous study, culture of peripheral blood mononuclear cells (PBMC) from myeloma patients with interleukin(IL)-4 and tumour necrosis factor(TNF)-alpha resulted in the appearance of clonal plasma cells, thus suggesting the presence of circulating myeloma cell precursors in the peripheral blood. Using the same cytokine combination, we cultured PBMC and purified peripheral blood B-cells from myeloma patients. In nearly all cases, partial differentiation of B-cells occurred but, similarly to results for normal controls, both kappa and lambda light chain (L.C.) cytoplasmic positive lymphoid and lymphoplasmacytoid cells were detected rather than clonal plasma cells. These results suggest that IL-4 and TNF-alpha cause partial differentiation of residual normal polyclonal B-cells rather than of circulating myeloma cell precursors in the peripheral blood of myeloma patients.     

The Streptomyces peucetius drrC gene encodes a UvrA-like protein involved in daunorubicin resistance and production

The drrC gene, cloned from the daunorubicin (DNR)- and doxorubicin-producing strain of Streptomyces peucetius ATCC 29050, encodes a 764-amino-acid protein with a strong sequence similarity to the Escherichia coli and Micrococcus luteus UvrA proteins involved in excision repair of DNA. Expression of drrC was correlated with the timing of DNR production in the growth medium tested and was not dependent on the presence of DNR. Since introduction of drrC into Streptomyces lividans imparted a DNR resistance phenotype, this gene is believed to be a DNR resistance gene. The drrC gene could be disrupted in the non-DNR-producing S. peucetius dnrJ mutant but not in the wild-type strain, and the resulting dnrJ drrC double mutant was significantly more sensitive to DNR in efficiency-of-plating experiments. Expression of drrC in an E. coli uvrA strain conferred significant DNR resistance to this highly DNR-sensitive mutant. However, the DrrC protein did not complement the uvrA mutation to protect the mutant from the lethal effects of UV or mitomycin even though it enhanced the UV resistance of a uvrA+ strain. We speculate that the DrrC protein mediates a novel type of DNR resistance, possibly different from the mechanism of DNR resistance governed by the S. peucetius drrAB genes, which are believed to encode a DNR antiporter.     

Anisotropy of fracture toughness in textured titanium-6Al-4V alloy

Fracture toughness tests have been carried out on a wide range of specimen orientations from textured Ti-6A1-4V alloy plate. The tests were instrumented to allow measurement of crack extension as well as stress intensity factors and COD data. Preferred orientation of the dominant alpha phase was found to influence not only the toughness parameters but also the fracture surface and propensity to shear lip formation. The anisotropic nature of plasticity in the material was demonstrated by direct measurement of yield loci and by the variable shapes of plastic zones around crack tips. Results are discussed in terms of a qualitative analysis of slip systems at the crack tip and also in a semiquantitative anisotropic upper bound slip line treatment. It is found that stable crack extension starts at low values ofK and COD for specimens in which plastic flow can occur readily at the crack tip but toughness, assessed as resistance to unstable crack propagation, is greatest in these cases. The magnitude of microstructure induced anisotropy is shown to be much smaller than that originating in preferred crystallographic orientation. Troughlike features on some fracture surfaces were found to be associated with regions of particularly strong local texture. Formerly with the Department of Physical Metallurgy, University of Birmingham     

The butt-fusion welding of PVDF and its composites

A wide range of mirror plate butt welding conditions were used to join PVDF pipe to pipe and to an injection moulded fitting. The microstructures of the welds were characterized by microtomy and by transmitted light microscopy, and the mechanical properties by tensile testing. The results show that high integrity pipe to pipe joins can be produced for a relatively wide range of welding conditons, and that the integrity of pipe to fitting joins may be reduced because of the adverse influence of the moulded part on weld bead geometry.     

Protection of yearling ponies against Strongylus vulgaris by foalhood vaccination

The long-term efficacy of an irradiation attenuated larval (L3) vaccine against Strongylus vulgaris was tested in ponies which were reared on pasture. Prior to foaling, mares were divided into two groups. One group of mares and foals received regular (eight weekly) treatment with ivermectin and the second group remained untreated. Half the foals in each pasture group were vaccinated at eight to ten weeks of age. Foals were weaned at three to four months of age and maintained on separate pastures. At eight to ten months of age, ponies were placed in box stalls and half of each treatment group were challenged with S. vulgaris (5 x 1000 L3). Clinical signs and lesions typical of acute verminous arteritis were found at necropsy in the ivermectin treated non-vaccinated challenged yearlings. Ivermectin treated vaccinated challenged yearlings did not show these clinical signs, had markedly reduced to absent arterial lesions and showed an 89 per cent reduction in arterial larval burdens post mortem. Significant differences in clinical signs, arterial lesions or arterial larval burdens were not seen between vaccinated and non-vaccinated foals reared without benefit of ivermectin treatment.     

Influence of microstructure on the dynamic fatigue properties of injection-moulded polypropylene

A polypropylene copolymer was injection-moulded using several processing conditions and with different gating systems to produce a range of typical spherulitic microstructures. In addition to internal weld lines, some specimens were joined to form external mirrorplate butt-welds. The effect of the different microstructures on the fatigue and impact properties as a function at two test temperatures of 23 and – 10° C are reported. The influence of the different microstructures resulted in significant differences in load-bearing ability.     

Isolation of Pichia pastoris genes involved in ER-to-Golgi transport

Pichia pastoris has discrete transitional ER sites and coherent Golgi stacks, making this yeast an ideal system for studying the organization of the early secretory pathway. To provide molecular tools for this endeavour, we isolated P. pastoris homologues of the SEC12, SEC13, SEC17, SEC18 and SAR1 genes. The P. pastoris SEC12, SEC13, SEC17 and SEC18 genes were shown to complement the corresponding S. cerevisiae mutants. The SEC17 and SAR1 genes contain introns at the same relative positions in both P. pastoris and S. cerevisiae, whereas the SEC13 gene contains an intron in P. pastoris but not in S. cerevisiae. Intron structure is similar in the two yeasts, although the favoured 5' splice sequence appears to be GTAAGT in P. pastoris vs. GTATGT in S. cerevisiae. The predicted amino acid sequences of Sec13p, Sec17p, Sec18p and Sar1p show strong conservation in the two yeasts. By contrast, the predicted lumenal domain of Sec12p is much larger in P. pastoris, suggesting that this domain may help localize Sec12p to transitional ER sites. A comparison of the SEC12 loci in various budding yeasts indicates that the SEC12-related gene SED4 is probably unique to the Saccharomyces lineage.     

Trace-gas detection in ambient air with a thermoelectrically cooled, pulsed quantum-cascade distributed feedback laser

A pulsed quantum-cascade distributed feedback laser operating at near room temperature was used for sensitive high-resolution IR absorption spectroscopy of ambient air at a wavelength of ~8 mum. Near-transform-limited laser pulses were obtained owing to short (~5-ns) current pulse excitation and optimized electrical coupling. Fast and slow computer-controlled frequency scanning techniques were implemented and characterized. Fast computer-controlled laser wavelength switching was used to acquire second-derivative absorption spectra. The minimum detectable absorption was found to be 3 x 10(-4) with 10(5) laser pulses (20-kHz repetition rate), and 1.7 x 10(-4) for 5 x 10(5) pulses, based on the standard deviation of the linear regression analysis.