Preparation of structurally-colored aromatic polyamides and their physicochemical properties

Conclusions One-, two-, and three-stage methods of preparing structurally-dyed aromatic polyamides with chromophoric fragments in the chain have been investigated.It has been shown that the molecular weight of the polymers obtained and the proportion of chromophores bound into their chain is determined by the reactivity of the starting diaminoanthraquinones.It has been found that the introduction of anthraquinone units into the poly-m-phenylene isophthalamide chain has little effect on the structure or basic physicochemical properties of the polyamide, but gives the polymer a uniform and regular coloration.Structural dyeing of poly-m-phenylene isophthalamide with fragments of 1,5-DAAQ or 4,8-DADHAQ increases the resistance of the polyamide fibres to UV irradiation.The authors express their thanks to Yu. Ya. Shavarin and N. M. Bol'bit for performance of the fibre irradiation, and also to B. A. Tsaplin for thermomechanical testing of the fibres.L. Ya. Karpov NIFKhI, Moscow. VNIISV, Tver'. Translated from Khimicheskie Volokna, No. 2, pp. 24–27, March–April, 1992.     

Computer telephony architectures: MVIP, H-MVIP, and SCbus

The author discusses the objectives of a computer-telephony integration (CTI) bus for the PC, TDM, network synchronization, digital switching, multichassis connections, MVIP bus technologies, SCbus technology, and CTI client server architectures     

Renal effects of aspirin and low dose methotrexate in rheumatoid arthritis

OBJECTIVES: The aim of this investigation was to study the glomerular and tubular effects of low doses (15 mg) of methotrexate in patients with rheumatoid arthritis with and without combined treatment with aspirin (2 g single dose). METHODS: Renal function was measured by the plasma clearance of EDTA labelled with chromium-51 (51Cr-EDTA) and mercaptoacetyltriglycine labelled with technetium-99m (99mTc-MAG-3). RESULTS: Clearance of 51Cr-EDTA was reduced from 98 (6) to 87 (5) ml/min (mean (SEM)) for patients receiving methotrexate only and further reduced to 76 (5) ml/min for patients receiving methotrexate and aspirin. This effect was reversible as 51Cr-EDTA increased to 85 (6) ml/min during continued treatment with methotrexate alone. Clearance of 99mTc-MAG-3 also decreased from 366 (18) to 315 (17) ml/min in patients receiving methotrexate alone and further to 295 (17) ml/min during treatment with aspirin and methotrexate. Continued treatment with methotrexate alone resulted in a further decrease in the 99mTc-MAG-3 clearance to 253 (17) ml/min. CONCLUSIONS: The study shows that treatment with low doses of methotrexate particularly when combined with aspirin affects glomerular and tubular function. These effects may be of clinical importance and renal function should therefore be monitored with more sensitive methods than serum creatinine as this may not reflect these changes.     

Frequent detection of human herpesvirus-6 sequences by polymerase chain reaction in paraffin-embedded lymph nodes from patients with angioimmunoblastic lymphadenopathy and angioimmunoblastic lymphadenopathy-like lymphoma

In search of a possible involvement of viral agents in angioimmunoblastic lymphadenopathy with dysproteinaemia (AILD) and AILD-like lymphoma (AILD-L), we studied the presence of human herpesvirus-6 (HHV-6) in the lymph node biopsies of 12 cases by polymerase chain reaction (PCR). Given the rarity of this lymphoproliferative disorder, we investigated archival specimens, consisting of formalin-fixed and paraffin-embedded tissues, obtained from patients with a clinical and histologic diagnosis of AILD and AILD-L. HHV-6 sequences were detected in the lymph node biopsies of 7 out of the 12 AILD and AILD-L cases examined. HHV-6 sequences were identified also in the involved liver and spleen tissues of one patient and in the PBMCs of two patients, all carrying viral sequences in the affected lymph nodes. We also used PCR to characterize the HHV-6 genomes, showing that two different viral strains are represented in the pathologic tissues. This study provides evidence of the presence of HHV-6 specific sequences in an unexpectedly high proportion of our series of AILD and AILD-L cases, suggesting a possible involvement of this lymphotropic virus in the pathogenesis of at least some cases of the disease.