Polymorphonuclear neutrophil granulocyte chemotactic hyperresponsiveness in a case of canine acromegaly

Growth hormone (GH) has recently been shown to affect polymorphonuclear neutrophil granulocyte (PMN) function and to be secreted by mononuclear cells, indicating that the hormone may be active in an immunophysiologic network, acting as an endo- or paracrine priming agent. The purpose of the present study was to evaluate the chemotactic responsiveness of canine peripheral PMN in a dog with acromegaly, caused by spontaneous, progesterone-induced hypersecretion of GH and, secondary to this, a seven-fold increase in insulin-like growth factor I (IGF-I). The chemotactic responsiveness towards zymosan-activated serum (ZAS) and leukotriene B4 (LTB4) was evaluated at a time when the dog suffered from acromegaly and again 57 days after corrective surgery (ovariohysterectomy). The experiments showed that PMN from the patient exhibited enhanced chemotactic migration that appeared to be associated with the hypersomatotropic condition as judged from the reversibility of the phenomenon. The glucose intolerance and elevated serum alkaline phosphatase that were observed in the acromegalic dog were also shown to be reversible following surgery.     

Systematic characterization of Cl2 reactive ion etchingfor improved ohmics in AlGaN/GaN HEMTs

Pre-metal-deposition reactive ion etching (RIE) was performed on an Al_0.3Ga_0.7N/AlN/GaN heterostructure in order to improve the metal-to-semiconductor contact resistance. An optimum AlGaN thickness for minimizing contact resistance was determined. An initial decrease in contact resistance with etching time was explained in terms of removal of an oxide surface layer and/or by an increase in tunnelling current with the decrease of the AlGaN thickness. The presence of a dissimilar surface layer was confirmed by an initial nonuniform etch depth rate. An increase in contact resistance for deeper etches was experienced. The increase was related to depletion of the two-dimensional (2-D) electron gas (2-DEG) under the ohmics. Etch depths were measured by atomic force microscopy (AFM). The contact resistance decreased from about 0.45 Ωmm for unetched ohmics to a minimum of 0.27 Ωmm for 70 Å etched ohmics. The initial thickness of the AlGaN layer was 250 Å. The decrease in contact resistance, without excessive complications on device processing, supports RIE etching as a viable solution to improve ohmic contact resistance in AlGaN/GaN HEMTs     

A Convenient Synthesis of Some Coumarin Derivatives Using SnCl2 · 2H2O as Catalyst

Some substituted coumarins have been synthesized by von-Pechmann condensation using SnCl₂ · 2H₂O (10 mol %) as catalyst in ethanolic medium. The reactions are simple, easy in handling and environmentally benign.     

Lipid free radical generation and brain cell membrane alteration following nitric oxide synthase inhibition during cerebral hypoxia in the newborn piglet

Nitric oxide (NO) is reported to cause neuronal damage through various mechanisms. The present study tests the hypothesis that NO synthase inhibition by N(omega)-nitro-L-arginine (NNLA) will result in decreased oxygen-derived free radical production leading to the preservation of cell membrane structure and function during cerebral hypoxia. Ten newborn piglets were pretreated with NNLA (40 mg/kg); five were subjected to hypoxia, whereas the other five were maintained with normoxia. An additional 10 piglets without NNLA treatment underwent the same conditions. Hypoxia was induced with a lowered FiO2 and documented biochemically by decreased cerebral ATP and phosphocreatine levels. Free radicals were detected by using electron spin resonance spectroscopy with a spin trapping technique. Results demonstrated that free radicals, corresponding to alkoxyl radicals, were induced by hypoxia but were inhibited by pretreatment with NNLA before inducing hypoxia. NNLA also inhibited hypoxia-induced generation of conjugated dienes, products of lipid peroxidation. Na+,K+-ATPase activity, an index of cellular membrane function, decreased following hypoxia but was preserved by pretreatment with NNLA. These data demonstrate that during hypoxia NO generates free radicals via peroxynitrite production, presumably causing lipid peroxidation and membrane dysfunction. These results suggest that NO is a potentially limiting factor in the peroxynitrite-mediated lipid peroxidation resulting in membrane injury.     

Detection of human papillomavirus in routinely processed biopsy specimens from laryngeal papillomas: evaluation of reproducibility of polymerase chain reaction and DNA in situ hybridization procedures

The frequency of human papillomavirus (HPV) in laryngeal papillomas varies largely among different studies. DNA in situ hybridization (ISH) has been the most widely used method for detection of HPV. The aim of this study was to compare the reproducibility and sensitivity of ISH with polymerase chain reaction (PCR) in 35 specimens of laryngeal papillomas routinely fixed in buffered or unbuffered formalin. Out of 12 specimens fixed in buffered formalin, 10 were positive for HPV 6/11 using ISH. The procedure was repeated three times and three specimens were positive only twice. Nine biopsies were positive for HPV using PCR with consensus primers (My 09/11) on dewaxed tissue without extracting DNA. In three repeated PCRs, the results were inconsistent in three samples. After DNA extraction, all 12 samples were positive with PCR. Of the 23 specimens fixed in unbuffered formalin, 14 were HPV-positive with ISH, while only one was positive with PCR. We concluded that PCR with My 09/11 consensus primers is a highly sensitive method for detection of HPV in laryngeal papillomas fixed in buffered formalin, but useless for samples fixed in unbuffered formalin. When DNA was extracted from the former type of fixed tissue, the results were highly reproducible. In contrast to PCR, ISH appeared to be less influenced by fixation procedure, but it was not as reproducible and sensitive as PCR. Negative results did not necessarily mean absence of HPV.     

Familial jejunal atresia with renal dysplasia

Although jejunal atresia occasionally may occur with a familial pattern, an association with renal disease has not been described. The authors report on three family members treated over two generations, all of whom had both proximal jejunal atresia and renal dysplasia. This association was most likely inherited as an autosomal dominant trait.