Some aspects of the communicating branch between the musculocutaneous and median nerves in man

Fascicular arrangement of the human brachial plexus is examined on 2 common cases and 3 peculiar cases in which a communicating branch was observed between the median and the musculocutaneous nerve. The musculocutaneous nerve consitss of spinal nerves from C.5, 6 and 7. The branch to the coracobrachialis receives its fibers from C.7 before it leaves the musculocutaneous nerve in 3 cases and after it leaves the musculocutaneous nerve in one case. In one case, C.7 does not send a branch to the coracobrachialis. The median nerve arises by two roots, one from the lateral cord, and the other from the medial cord of the brachial plexus. In a case in which a communicating branch was observed from the median nerve to the musculocutaneous, the fibers from C.7 join to the median nerve via the medial cord. Thus the median nerve involved all elements of the spinal nerve from C.5 to T.1. The elements of the median and the musculocutaneous nerves, therefore, are not affected by appearance of the communicating branch. The communicating branch between the median and the musculocutaneous nerves, consists of the fibers arose from C.5 and C.6, in all examined cases.     

Comparison of proviral accessory genes between long-term nonprogressors and progressors of human immunodeficiency virus type 1 infection

Summary.  We compared proviral accessory gene sequences (nef, vpu, vpr, vif, rev, tat) of human immunodeficiency virus type 1 (HIV-1) in the peripheral blood mononuclear cells (PBMC) between seven long-term non-progressors (LTNP) and seven progressors. LTNP frequently harbored proviruses with mutated accessory genes, while almost all accessory genes were intact in progressors. Presence of quasispecies in attenuated viruses suggests that they were not just a fossil record of nonreplication proviruses. These attenuated viruses in LTNP may be the source of their strong immune response against HIV-1. Our result might have relevance to a design of potent therapeutic vaccines. Received November 16, 1999/Accepted January 14, 2000     

Cardiac rhabdomyoma. A case report with reference to atrial natriuretic peptide

An autopsy case of cardiac rhabdomyoma in a male infant is reported. Many nodules of rhabdomyoma were present in all four cardiac chambers and were microscopically composed of ovoid, glycogen-laden cells and typical "spider cells". Atrial natriuretic peptide (ANP) was immunohistochemically demonstrated in both normal myocytes and rhabdomyoma cells of both atria, but not in normal myocytes and rhabdomyoma cells of both ventricles. Ultrastructurally, atrial specific granules were present in atrial rhabdomyoma cells and normal atrial cardiocytes, and these showed ANP immunoreactivity with protein A-gold technique. It could be said that the localization and intracellular distribution of ANP in this cardiac rhabdomyoma were closely similar to those of normal human heart. With regard to the presence of ANP, cardiac rhabdomyoma cells arising in atria seemed to differ from those in ventricles, although many tumor nodules occurred in both atria and ventricles. Furthermore, it seemed that cardiac rhabdomyomas could also be divided into two parts: 1) an atrial part with ANP, and 2) a ventricular part without ANP. Therefore, this study confirms the hypothesis that cardiac rhabdomyoma is a hamartoma rather than a true neoplasm.     

Cardiac ankyrin repeat protein is preferentially induced in atrophic myofibers of congenital myopathy and spinal muscular atrophy

Cardiac ankyrin repeat protein (CARP), which is structurally characterized by the presence of four ankyrin repeat motifs in its central region, is believed to be localized in the nucleus and to participate in the regulation of cardiac-specific gene expression in cardiomyocytes. However, we recently found that CARP was induced in skeletal muscle by denervation, leading us to speculate that CARP may be induced under some pathological conditions. In the present study, we immunohistochemically analyzed the expression of CARP in 11 cases of spinal muscular atrophy (SMA) and 14 cases of congenital myopathy. In SMA, CARP was expressed selectively in severely atrophic myofibers, suggesting that CARP expression may reflect the status of muscle atrophy. Furthermore, in the congenital myopathies, the expression patterns of CARP were distinct among the subtypes, which included nemaline myopathy, myotubular myopathy, central core disease, and congenital fiber type disproportion. Although CARP was preferentially expressed in severely damaged myofibers in nemaline myopathy, it was not detected in central core disease. These findings suggest that immunohistochemical evaluation of CARP may be helpful in the diagnosis of SMA and the congenital myopathies.     

Time-resolved two-dimensional X-ray diffraction study of the effect of shortening on activation of contracting skeletal muscle

In twitch contractions of frog skeletal muscle, the isometric tension peaks when intracellular calcium has fallen to near-resting levels. To understand the mechanism of this delayed tension maintenance in the context of calcium regulation, the time course of the tropomyosin movement on actin was monitored by recording the intensity of the 2nd actin layer lines in a time-resolved two-dimensional X-ray diffraction study. The intensity rose ahead of tension, reflecting the tropomyosin movement from its "off" to "on" positions, but it fell with a time course similar to that of tension. Muscle shortening applied at the tension peak was followed by a poor recovery of tension, and accelerated the fall of the reflection intensity. The results suggest that the force-generating myosin heads retain the tropomyosin in its "on" position after the fall of intracellular calcium, and their shortening-induced detachment makes the tropomyosin return to its "off" position, thereby preventing myosin reattachment to actin.     

Neutral endopeptidase (EC 3.4.24.11) does not hydrolyze recombinant human interleukin-1 beta.

We have previously shown that neutral endopeptidase (NEP; EC 3.4.24.11) regulates neuropeptide-induced responses. Recently, Pierart et al. reported that NEP degraded purified interleukin-1 (IL-1) using thymocyte proliferation assay. Since IL-1 is an important cytokine in the immune response and inflammation, we have assessed whether NEP hydrolyzes recombinant human IL-1 beta using three assay systems (bioassay, immunoassay, and HPLC analysis). NEP on the NALM-6 cells (both intact cells and the solubilized plasma membrane fraction) efficiently hydrolyzed Met5-enkephalin and substance P. However, NEP did not significantly decrease the amount of rhIL-1 beta assessed by the growth inhibitory activity of a human melanoma, by the immunoassay, or by the direct analysis on HPLC. Therefore, we conclude that NEP does not significantly hydrolyze rhIL-1 beta. Our results suggest that, in contrast to the regulatory role of NEP in neuropeptide-induced responses, NEP is not a regulatory enzyme for IL-1-induced responses.     

Whole-cell currents from the cloned canine cardiac Na+/Ca2+ exchanger NCX1 overexpressed in a fibroblast cell CCL39

 A conventional patch-clamp technique was used to record the whole-cell current from the cloned canine cardiac Na⁺/Ca²⁺ exchanger NCX1 overexpressed in a fibroblast cell. Ca²⁺ was extracellularly applied to the Na⁺-loaded cell to activate the outward current by operating the reverse mode of NCX1. No measurable outward current was ever elicited from the nontransfected cell. Na⁺/Ca²⁺ exchange blocker 5 mM Ni²⁺ or 3 μM KB-R7943 that was applied extracellularly abolished the outward current. With 140 mM external Li⁺ (replacing Na⁺), the outward current was transient during the Ca²⁺ application. In contrast, with 140 mM external Na⁺, the outward current was maintained without any inactivation during the Ca²⁺ application. I–V relations predicted from the whole-cell clamp protocols used were obtained both before and during the Ca²⁺ application. The exchanger whole-cell currents are thus successfully detectable from NCX1 which is overexpressed in this stable transfectant system. Received: 28 February 1997 / Accepted: 9 April 1997     

Transport of magnesium by two isoforms of the Na+-Ca2+ exchanger expressed in CCL39 fibroblasts

Cytoplasmic concentrations of Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) were measured with fluorescent indicators in CCL39 cells, a cell line established from Chinese hamster lung fibroblasts, transfected with complementary deoxyribonucleic acid (cDNA) of the Na+-Ca2+ exchanger isolated either from canine heart (NCX1) or from rat brain (NCX3). Raising extracellular [Mg2+] to 10 mM increased Mg2+ influx and the resultant change in [Mg2+]i (delta[Mg2+]i) was monitored with furaptra under Ca2+-free conditions. In control (vector-transfected) cells, delta[Mg2+]i at 45 min was similar with or without extracellular Na+ (130 mM or 0 mM) and when [Na+]i was raised by 1 mM ouabain treatment. delta[Mg2+]i in NCX1-transfected cells was attenuated significantly in the presence of 130 mM Na+, but became comparable to (or slightly larger than) that in control cells on either removal of extracellular Na+ or treatment with 1 mM ouabain. Cells expressing NCX3 showed an intermediate dependence of delta[Mg2+]i on Na+, probably reflecting a lower degree of expression of the exchanger protein. Extracellular Na+-dependent changes in [Ca2+]i (measured with fura-2 in the presence of extracellular Ca2+ and 10 microM ionomycin, a Ca2+ ionophore) were minimal in control cells, marked in the NCX1-transfected cells and intermediate in the NCX3-transfected cells. These results suggest that the Na+-Ca2+ exchanger (either NCX1 or NCX3) can transport Mg2+ and may play a role in the extrusion of magnesium from cells.     

Disturbed pyloric motility in Ws/Ws mutant rats due to deficiency of c-kit expressing interstitial cells of Cajal

Interstitial cells of Cajal (ICC) are believed to lnitlate the basic contractile activity of the gastrointestlnal tract. Interstitial cells of Cajal express c-kit receptor tyroslne kinase and are deficient in Ws/Ws mutant rats with a small deletion of the c-kit gene . As Ws/Ws rats show remarkable bile reflux to the stomach, the contraction pressure of the pylorus was compared between Ws/Ws and control +/+ rats. The contraction pressure of the pylorus was measured using a mlcrotransducer, which was Inserted through a pln-hole in the anterlor wall of the stomach under anesthesla. The magnitude of bile reflux was estimated by measurlng the content of bile acids In the stomach. The c-kit messenger RNA-expressing cells were detected by in sltu hybrldlzatlon. Frequency and the maxlmum pressure of the contractlon were comparable between Ws/Ws and +/+ rats, but the duration of the contractlon was significantly shorter In Ws/Ws rats than In +/+ rats. The number of c-kit messenger RNA-expresslng ICC in the pylorus of Ws/Ws rats was 1.7% that of +/+ rats. The bile reflux observed in Ws/Ws rats was attributed to the decrease in the duration of the pyloric contraction, which appeared to result from the deficlency of c-kit messenger RNA-expressing ICC.     

Effect of vitamin K2 on cortical and cancellous bones in orchidectomized young rats

OBJECTIVES: The purpose of the present study was to compare the effect of vitamin K(2) on cortical and cancellous bones in orchidectomized young rats. METHODS: Forty male Sprague-Dawley rats, 6 weeks of age, were randomized by stratified weight method into four groups with 10 rats in each group: baseline controls (BLC), age-matched controls (AMC), orchidectomy (ORX), and ORX+vitamin K(2) administration (K). Vitamin K(2) (menatetrenone) was administered subcutaneously twice a week at dose of 30 mg/kg each. The experimental period was 8 weeks, and cortical and cancellous bone histomorphometry was performed on the tibial shaft and the proximal tibia, respectively. RESULTS: Cortical area (Ct Ar) and cancellous bone volume (BV/TV) were significantly greater in the AMC group than in the BLC group. Ct Ar was significantly lower in the ORX group than in the AMC group, and cancellous BV/TV was also significantly lower in the ORX group than in the AMC group as a result of significantly increased eroded surface (ES/BS). Although Ct Ar in the ORX+K group did not differ significantly from that in the ORX group, cancellous BV/TV was significantly greater in the ORX+K group than in the ORX group, but still significantly lower than in the AMC group. This protective effect of vitamin K(2) on cancellous bone was attributable to normalizing increased ES/BS. CONCLUSIONS: Vitamin K(2) appears to act more strongly on cancellous bone than on cortical bone in ORX young rats. High dose vitamin K(2) could partially prevent the reduction of cancellous bone gain by normalizing raised bone resorption in ORX young rats.