Periodic isorhythmic dissociation during enflurane anesthesia in a patient with Sinus Bradycardia

Key words  dysrhythmia - isorhythmic dissociation - oscillation     

Study on the developing potentiality of mouse morula produced in vitro or in vivo after vitrification

Great horovement haS been made in the cryopreservation Of inalnlnalian elnbmp since wnttingham['] reported his Pioneering wold about successful cryOPreservationof mouse embryo. It results in the availability of cryOPreserVation of embryos of all stages[']. HOwever, cryopreserved embryos can not avoid the damages by ice crystal,which is a major cause of cen death in the freezing andthawing ProceduresL',']. SO it is necesseq to seareh for anew and more efficient method for embryO cryOPrese…     

Inhibition of Ca2+ channel current by μ- and κ-opioid receptors coexpressed in Xenopus oocytes: desensitization dependence on Ca2+ channel α1 subunits

1. Desensitization of μ- and κ-opioid receptor-mediated inhibition of voltage-dependent Ca²⁺ channels was studied in a Xenopus oocyte translation system.
2. In the oocytes coexpressing κ-opioid receptors with N- or Q-type Ca²⁺ channel α₁ and β subunits, the κ-agonist, U50488H, inhibited both neuronal Ca²⁺ channel current responses in a pertussis toxin-sensitive manner and the inhibition was reduced by prolonged agonist exposure.
3. More than 10 min was required to halve the inhibition of Q-type channels by the κ-agonist. However, the half-life for the inhibition of N-type channels was only 6±1 min. In addition, in the oocytes coexpressing μ-opioid receptors with N-type or Q-type channels, the uncoupling rate of the μ-receptor-mediated inhibition of N-channels was also faster than that of Q-type channels.
4. In the oocytes coexpressing both μ- and κ-receptors with N-type channels, stimulation of either receptor resulted in a cross-desensitization of the subsequent response to the other agonist. Treatment of oocytes with either H-8 (100 μM), staurosporine (400 nM), okadaic acid (200 nM), phorbol myristate acetate (5 nM) or forskolin (50 μM) plus phosphodiesterase inhibitor did not affect either the desensitization or the agonist-evoked inhibition of Ca²⁺ channels.
5. These results suggest that the rate of rapid desensitization is dependent on the α₁ subtype of the neuronal Ca²⁺ channel, and that a common phosphorylation-independent mechanism underlies the heterologous desensitization between opioid receptor subtypes.

     

Influence of denervation on neurogenic inhibitory response of corpus cavernosum and nitric oxide synthase histochemistry

Aims of this study were to functionally and histologically determine the localization of ganglia that distribute inhibitory nerves to the penile corpus cavernosum in dogs. In isolated corpus cavernosa from seven control dogs contracted with endothelin-1, transmural electrical stimulation (5 Hz for 40 s) elicited contractions which were reversed to relaxations by prazosin. The relaxation was abolished by NG-nitro-l-arginine (l-NNA), a nitric oxide (NO) synthase inhibitor, and restored by l-arginine. Parts of bilateral pelvic nerve plexuses running to the penis were surgically denervated in anesthetized three dogs, or the bilateral neuronal tissues close to the corpus cavernosum were removed for denervation in seven dogs. One week after the operation, the dogs were sacrificed. Denervation of pelvic plexus did not attenuate neurogenic relaxations, whereas denervation of the distal portion abolished the responses. In the tissues close to the corpus cavernosum excised for denervation, ganglia containing abundant nerve cells and fibers stained by nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase method were histochemically detected. One week after the denervation, there were no NADPH diaphorase-positive nerve fibers in the trabecula of corpus cavernosum. It is concluded that neurogenic relaxations of canine corpus cavernosum are mediated by NO synthesized from l-arginine in nerve terminals, and this nerve is originated from ganglia located close to the corpus cavernosum but not directly from the pelvic nerve plexus.     

Impact of gender on exocrine gland inflammation in mouse models of Sj?gren's syndrome.

Sj?gren's syndrome is a complex autoimmune disorder, that occurs almost exclusively in females, induces extensive lymphocyte accumulation in lacrimal and salivary glands, and represents one of the leading causes of dry eye and mouth in the world. The purpose of this study was to determine whether the profound, gender-related differences observed in the magnitude of exocrine gland inflammation in Sj?gren's syndrome may also be found in tissues of mouse models of this disorder. Lacrimal and submandibular glands were obtained from adult MRL/lpr, MRL+/+ (MRL+), NZB/NZW F1 (F1), C3H/lpr, C3H/gld (gld), C57BL/6-lpr/lpr [B6/lpr; with (bcl-2(+)/lpr) or without (bcl-2(-)/lpr) bcl-2 transgene insertion] and nonobese diabetic (NOD) mice after the onset of autoimmune disease, and processed for microscopy and image analysis. Our results showed that: (1) the extent of inflammation was significantly greater in lacrimal glands of female MRL/lpr, MRL+, F1, C3H/lpr and gld mice, and salivary glands of female MRL+, F1 and gld mice, relative to those of males; (2) the severity of inflammation in NOD mice showed a tissue-specific pattern: inflammation was far worse in lacrimal glands of males, whereas immune pathology was far greater in salivary tissues in females; and (3) no gender-related variations were present in the degree of inflammation in lacrimal glands of bcl-2(+)/lpr and bcl-2(-)/lpr mice or in submandibular tissues of MRL/lpr, C3H/lpr, bcl-2(+)/lpr and bcl-2(-)/lpr mice. Our findings demonstrate that gender-, strain- and tissue-related differences exist in the extent of inflammation in several mouse models of Sj?gren's syndrome.     

Improvement of brain single photon emission tomography (SPET) using transmission data acquisition in a four-head SPET scanner

Attenuation coefficient maps (-maps) are a useful way to compensate for non-uniform attenuation when performing single photon emission tomography (SPET). A new method was developed to record single photon transmission data and a-map for the brain was produced using a four-head SPET scanner. Transmission data were acquired by a gamma camera opposite to a flood radioactive source attached to one of four gamma cameras in the four-head SPET scanner. Attenuation correction was performed using the iterative expectation maximization algorithm and the-map. Phantom studies demonstrated that this method could reconstruct the distribution of radioactivity more accurately than conventional methods, even for a severely non-uniform-map, and could improve the quality of SPET images. Clinical application to technetium-99m hexamethylpropylene amine oxime (HMPAO) brain SPET also demonstrated the usefulness of this method. Thus, this method appears to be promising for improvement in the image quality and quantitative accuracy of brain SPET.This work was presented in part at the World Congress on Medical Physics and Biomedical Engineering, 7–12 July 1991, Kyoto, Japan     

Analysis of the potentiating action of NG-nitro-l-arginine on the contraction of the dog temporal artery elicited by transmural stimulation of noradrenergic nerves

Summary Dog temporal artery strips without endothelium responded to transmural electrical stimulation with a contraction which was potentiated by N^G-nitro-l-arginine (l-NNA). The noradrenaline-induced contraction and the release of 3H-noradrenaline were not affected. The stimulation-induced contraction was reversed to a relaxation by phentolamine. The relaxation was not influenced by timolol and atropine but inhibited by l-NNA; l-arginine abolished the inhibition. Transmural stimulation released NO_x from the arteries, the release being abolished by l-NNA. Potentiation by l-NNA of the neurally-induced contraction appears to be due to elimination of NO produced by non-adrenergic, non-cholinergic vasodilator nerve activation. Send offprint requests to N. Toda at the above address     

Electron microscopical and immunohistochemical studies on the induction of "Qi" employing needling manipulation.

During a sparrow-pecking and twisting-needle manipulation to the acupoints BL 23, 24 and 25 for an induction of "Qi", it was found that some transparent materials were binding to the needles after removed from the volunteer's skin. Electron-microscopical analysis of the transparent materials revealed that they corresponded to the injured fascia made up of collagen fibers, elastic fibers, fibroblasts, adipocytes and mast cells. Rarely were nerve fiber-like structures observed in the materials. Immunohistochemically, calcitonin gene-related peptide-positive nerve fibers could be demonstrated in the acupoint BL 24 associated fascia. A possible functional relationship between the needle manipulation and the induction of Qi-sensation is discussed along with the acupoint tissue constitution.