Lethal Midline Granuloma Presenting as Facial Cellulitis.

Lethal midline granuloma (Midline granuloma, Midline reticulosis, Polymorphic reticulosis, and Angiocentric immunoproliferative lesion) is relatively a rare entity of unknown etiology characterized by a massive destruction, erosion and mutilation of the tissues of nose and upper respiratory passages. Unlike Wagner’s granulomatosis which is known for its multi organ involvement, lethal midline granuloma remains usually localized. Without therapeutic intervention it has a very high mortality. Radiotherapy is the treatment of choice which considerably improves both quality and quantity of life. Addition of chemotherapy gives additional benefit. Sporadic cases have appeared in literature from time to time under various synonyms.

Changes in myosin ATPase activity in skeletal muscles of rat during cold stress.

Three skeletal muscles viz., gastrocnemius, pectoralis and diaphragm from rats acclimated to a low temperature (4 +/- 1 degrees C; 16 hr daily; maximum for 8 weeks) exhibit an increased myosin ATPase activity. An analysis of native myosin from these muscles under non-dissociating conditions reveals two myosin isozymes instead of a single isozyme expressed in control muscles. Isoelectric focusing (IEF) coupled with two dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2-D SDS-PAGE) confirms an increased phosphorylation of myosin light chain 2 (MLC2) in muscles from cold acclimated rats.

Myosin isoforms in uterine smooth muscle during pregnancy in rat.

Effects of uterine stretching and physiological hypertrophy on myosin isozyme were investigated in rat during pregnancy. Both nonpregnant and pregnant rat uteri express a single myosin band on native gels. Analysis of native myosin under denaturing conditions revealed two myosin heavy chains (MHCs) with molecular mass of 204 and 200 kDa respectively. Filamin, a 240 kDa protein co-electrophoreses with myosin on native gels. No correlation is found between regulatory myosin light chain phosphorylation and pattern of myosin isozymes or the MHC. The results suggest that uterine stretching and physiological hypertrophy during pregnancy do not induce any changes in uterine myosin isozyme.

Changes in uterine myosin isozymes from goat during early pregnancy.

Changes in the expression of native myosin, myosin heavy chains (MHCs) and myosin light chains (MLCs) were investigated in goat uterus during early pregnancy. Electrophoresis of native myosin under non dissociating conditions displayed two isozymes differing in their proportions during gestation. Three MHC isoforms were obtained following sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Whereas 204 kDa (a smooth muscle MHC) and 196 kDa (a non muscle MHC) were recorded in uterus from non pregnant goat, uterus of pregnant goat displayed a third 200 kDa smooth muscle MHC. Two conspicuous proteins (154 and 140 kDa respectively) in addition to MHCs were also obtained when the myofibrillar extracts were analysed either in the presence or absence of proteolytic inhibitors. Non pregnant goat uterus showed a basal level (ca.5%) of phosphorylation of regulatory myosin light chain. Uterine myosin from pregnant goat was recorded in a completely dephosphorylated state.

Myosin light chains (MLCs) heterogeneity in mammalian smooth and cardiac muscle.

A comparative study of myosin light chains (MLCs) has been made in the aorta, uterine and cardiac muscles (auricle, ventricle) of mice, pig, sheep and goat. Analysis of myosin light chains by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE) has revealed that (a) aorta myosin from mice, goat and pig has identical myosin light chains profile but pig aorta myosin lacks LC-2f; (b) uterine smooth muscle myosin depicts absence of LC-1f in sheep. Whereas satellite bands of LC-1f and LC-2f fractions are absent in pig uterine myosin, mice shows duplets for both the myosin light chains; (c) the auricular myosin in pig and goat is identical to chicken gizzard myosin used as reference and exhibits ALC-2s and ALC-1s fractions only while sheep auricular myosin lacks in ALC-1f; (d) the mice ventricular myosin depicts two satellite MLCs associated with fast migrating VLC-1s.

Effects of denervation and nerve crushing on chicken muscle.

When compared with the standard free muscle grafts, predenervated and nerve crushed chick gastrocnemius muscle grafts followed an identical and ordered sequence of tissue degeneration-regeneration. Atrophy of the fibres during ischaemic degeneration was accompanied by loss of weight, noncollagenous proteins and increment in lytic enzymes (acid and alkaline phosphatase), glucose 6-phosphatase, glycogen and succinate dehydrogenase. Regeneration was more rapid in standard free muscle grafts. Trophic insults to muscle via denervation and nerve crushing prior to transplantation did not influence graft renewal when compared with standard free muscle grafts though relatively increased recovery was shown by predenervated muscle grafts.

Endothelin-1 and carbachol: differences in contractile effects and myosin phosphorylation in lamb tracheal smooth muscle.

Endothelin-1 is a new potent vasoconstrictor peptide produced by the endothelial cells. The contractile effects of endothelin-1 (ET-1) were compared with those of cabachol in lamb tracheal smooth muscle. Equimolar concentrations (10(-6)M) of endothelin 1 and carbachol elicit rapidly rising isometric tension which is maintained indefinitely in a steady state when fibres are stimulated with carbachol. Fibre strips exposed to ET-1 cannot maintain peak isometric force beyond 15-20 min and instead these exhibit a decline in tension towards near relaxed state. In addition to an early transient relaxation, ET-1 stimulation results in a 20,000 Da myosin light chain phosphorylation pattern different from that of carbachol stimulation.

Endothelin-1 and okadaic acid induced contractions in tracheal smooth muscle of lamb.

Stimulation of lamb tracheal smooth muscle fibre strips with endothelin-1 and okadaic acid results in the development of isometric tensions which are long lasting. However, endothelin-1 is more potent constrictor than okadaic acid. An analysis of 20,000 Da regulatory myosin light chain by two-dimensional gel electrophoresis shows an identical phosphorylation pattern.

Reversal of endothelin-1-induced contractions by isoproterenol without myosin dephosphorylation in tracheal smooth muscle.

Effects of isoproterenol on isometric force, and 20,000 Da myosin light chain (LC20) phosphorylation were examined in smooth muscle fibre strips from lamb trachea stimulated with endothelin-1 (ET-1). ET-1 induced a rapidly rising isometric tension which was coupled with a multiple site phosphorylation of LC20. Isoproterenol addition at the time of peak isometric force resulted in a brisk relaxation of the fibre strips. Myosin light chain phosphorylation, however, remained unaffected.