Choline acetyltransferase activity and evoked spinal cord potentials for diagnosis of brachial plexus injury.

The purpose of this study is to investigate the diagnostic value of evoked spinal cord potentials (ESCPs) and choline acetyltransferase (CAT) activity during exploration of injuries to the brachial plexus. We assessed 25 spinal roots in 19 patients. The results of the two investigations were consistent in all except two roots. Although assessment of ESCPs is easy and quick, it mainly records the nerve potentials along the sensory pathway. Although measurement of CAT activity needs a specimen of the nerve and the availability of a radioisotope laboratory, it gives direct information regarding the motor function of ventral spinal roots. These two techniques should be complementary to each other in order to achieve a more accurate diagnosis.

Expression of ribosomal protein L4 (rpL4) during neurogenesis and 5-azacytidine (5AzC)-induced apoptotic process in the rat.

5-Azacytidine (5AzC) induces neuronal apoptosis in rat and mouse fetuses. 5AzC also induces apoptosis in undifferentiated PC12 cells, and ribosomal protein L4 (rpL4) mRNA expression increases prior to apoptosis. To clarify the roles of rpL4 during neurogenesis, we first examined the distribution of rpL4 mRNA in the developing rat brain by in situ hybridization and RT-PCR, and compared the results to the distribution of TUNEL- or PCNA-positive cells. rpL4 mRNA expression was strong in the ventricular zone (VZ), subventricular zone (SVZ), cortical plate (CP), cerebral cortex, granule cell layer (GCL), pyramidal cell layer (Py) and external granular layer (EGL) during embryonic and early postnatal days, and it was remarkably weakened thereafter. A lot of PCNA-positive cells were observed in VZ, SVZ, and EGL during embryonic and early postnatal days, and such distribution of PCNA-positive cells was almost identical to rpL4 mRNA distribution. Only few TUNEL-positive cells were observed in VZ, SVZ, cerebral cortex, EGL, and hippocampus during embryonic and early postnatal days, and the regions with TUNEL-positive cells were not identical to rpL4 mRNA distribution. Next, the changes of rpL4 mRNA expression in the brain of 5AzC-treated rat fetuses were examined by in situ hybridization and RT-PCR. Apoptotic cells appeared at 9 to 24 hours after treatment (HAT). However, the rpL4 mRNA expression was unchanged during the apoptotic process. From the results, it is suggested that rpL4 would have certain roles in cell proliferation and differentiation during neurogenesis, but have no roles in 5AzC-induced apoptosis in the fetal brain.

Mulberry leaf extract inhibits the oxidative modification of rabbit and human low density lipoprotein.

In a previous study, we demonstrated that the intake of mulberry leaves or their 1-butanol extract (MLBE) reduced the concentration of serum lipids and atheromatous thickening of arterial intima in hypercholesterolemic rabbits. In the present study, we investigated the antioxidative activity of MLBE and isoquercitrin, the main component of MLBE. First, we determined the effect on a stable radical agent, finding that quercetin, isoquercitrin and MLBE scavenged the DPPH radical. We then determined the copper-induced oxidative modification of rabbit and human low-density lipoprotein (LDL). Oxidation of LDL was spectrophotometrically monitored by changes in absorbance at 234 nm accompanied by the formation of conjugated dienes, and measured the formation of thiobarbituric acid reacting substances (TBARS). Quercetin, an aglycone of isoquercitrin, inhibited the formation of conjugated dienes and TBARS by copper-induced oxidative modification of rabbit and human LDLs. MLBE and isoquercitrin also inhibited the oxidation of LDL. These results indicate that mulberry leaves inhibit the oxidative modification of LDL and suggest that mulberry leaves may had prevent atherosclerosis.

A pitch glide activates an intermediate response between auditory N1 and mismatch negativity.

Pitch glides of a continuous tone elicit auditory N1-like responses. However, their characteristics have not well been investigated, and it remained unclear whether the response is an auditory true N1 or the mismatch negativity (MMN). We found here that a rapid pitch glide activates almost the same response as a true N1. On the contrary, as the rate of the pitch glide decreases, the response continuously varies the characteristics from true N1 to MMN. This suggests that there would exist intermediate responses between auditory N1 and MMN.

The development of bone changes induced in rats by recombinant human granulocyte colony-stimulating factor is suppressed by bisphosphonate.

We have previously demonstrated that high doses of recombinant human granulocyte colony-stimulating factor (rhG-CSF) induce bone changes characterized by osteoclastic bone resorption and osteogenesis due to intramembranous ossification in rats. In this communication we examined the effects of a pretreatment with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP), which is a powerful inhibitor of osteoclastic bone resorption, on bone changes induced by rhG-CSF in order to investigate the relation between osteoclastic bone resorption and osteogenesis. AHPrBP (5 mg/kg/day) was subcutaneously given to 6-week-old rats for 2 days. From the following day of the final injection of AHPrBP, rats received a subcutaneous injection of rhG-CSF (1,000 micrograms/kg/day) for 14 days, and the femur and tibia were evaluated histopathologically. By the analysis of peripheral blood leukocyte counts, spleen weights and bone marrow findings, the pretreatment with AHPrBP had no effect on the activation of hematopoiesis related to the major pharmacological activity of rhG-CSF. In the rats treated with rhG-CSF alone, accelerated osteoclastic bone resorption and osteogenesis due to intramembranous ossification were observed in the trabeculae of metaphyseal spongiosa. The accelerated osteoclastic bone resorption induced by rhG-CSF was suppressed by the pharmacological activity of AHPrBP. Furthermore, the osteogenesis induced by rhG-CSF was also suppressed by AHPrBP. These results suggest that the osteogenesis induced by rhG-CSF is a sequential reaction of accelerated osteoclastic bone resorption, and moreover that the main action of rhG-CSF on bone is an acceleration of osteoclastic bone resorption.

BASH, a novel signaling molecule preferentially expressed in B cells of the bursa of Fabricius.

The bursa of Fabricius is a gut-associated lymphoid organ that is essential for the generation of a diversified B cell repertoire in the chicken. We describe here a novel gene preferentially expressed in bursal B cells. The gene encodes an 85-kDa protein, designated BASH (B cell adaptor containing SH2 domain), that contains N-terminal acidic domains with SH2 domain-binding phosphotyrosine-based motifs, a proline-rich domain, and a C-terminal SH2 domain. BASH shows a substantial sequence similarity to SLP-76, an adaptor protein functioning in TCR-signal transduction. BASH becomes tyrosine-phosphorylated with the B cell Ag receptor (BCR) cross-link or by coexpression with Syk and Lyn and associates with signaling molecules including Syk and a putative chicken Shc homologue. Overexpression of BASH results in suppression of the NF-AT activation induced by BCR-cross-linking. These findings suggest that BASH is involved in BCR-mediated signal transduction and could play a critical role in B cell development in the bursa.

Auditory evoked off-response: its source distribution is different from that of on-response.

Offset auditory responses were investigated by electroencephalography mainly in the 1970s, but since then no particular attention has been paid to them. Among the studies using magnetoencephalography (MEG) devices there are, to our knowledge, only three studies of the auditory off-response, and no significant variance has ever been observed between the source locations of on- and off-responses elicited from pure tones. We measured auditory evoked magnetic fields (AEFs) to various frequency pure tone stimulation in 5 healthy subjects with a 122-channel helmet-shaped magnetometer, and compared the distributions of the source locations of auditory N100m-Off (magnetic off-response around 100 ms) with those of N100m-On. Their spatial distributions were quite close to each other, and yet they were significantly different.

Effects of fructose-induced hypertriglyceridemia on hepatorenal toxicity of acetaminophen in rats. II. Role of enhancement of fructose metabolism and overproduction of triglyceride in the liver and kidney on hepatorenal toxicity of acetaminophen.

Fructose-induced hypertriglyceridemic rats are resistant to hepatoxicity and susceptible to nephrotoxicity of acetaminophen (APAP) as compared with normal ones. The present studied were designed to evaluate how fructose-treatment affects the developmental mode of hepatorenal toxicity of APAP. First, following fructose-pretreatment for various durations (1 day, 1 week or 3 weeks), 1-day-fructose-pretreatment induced hypertriglyceridemia and enhancement of APAP-nephrectoxicity simultaneously. However, it took at least 3 weeks for fructose-pretreatment to reduce APAP-hepatotoxicity. Second, following fructose, sucrose or glucose-pretreatment for 3 weeks, fructose-pretreated rats showed marked hypertriglyceridemia and modification of APAP-hepatorenal toxicity. Sucrose-pretreated rats showed less effects than fructose-pretreated rats. Glucose-pretreated rats showed no changes in plasma triglyceride and APAP-hepatorenal toxicity. Third, rats with hypertriglyceridemia induced by olive oil or Triton WR-1339 which did not produce enhanced metabolism and triglyceride-overproduction in the liver and kidney showed no modification of APAP-hepatorenal toxicity. Pretreatment of glycerol which was metabolized in liver and kidney and induced an overproduction of triglyceride resulted in an enhancement of APAP-nephrotoxicity. These results indicate that an enhancement of fructose metabolism and an overproduction of triglyceride in liver and kidney are responsible for the modification of APAP-hepatorenal toxicity in fructose-induced hypertriglyceridemic rats.

Mineralocorticoid type I receptor in the rat cochlea: mRNA identification by polymerase chain reaction (PCR) and in situ hybridization.

Expression of mineralocorticoid type I receptor (MR) gene in the rat cochlea was determined using molecular biological techniques. We synthesized complementary DNA (cDNA) from rat cochlear total RNA and then amplified MR cDNA fragments by polymerase chain reaction (PCR). The amplified cDNA fragments were subcloned into an expression vector and the nucleotide sequence was analyzed to confirm the expression of mRNA encoding MR in the cochlea. We then synthesized digoxigenin-labeled riboprobes with this cloned DNA template and examined the localization of MR mRNA in the cochlea by in situ hybridization. The amino acid sequence of MR cDNA expressed in the cochlea was identical to that of the MR first cloned in the rat hippocampus. In situ hybridization showed the expression of MR mRNA in marginal cells of the stria vascularis, suggesting that aldosterone may regulate microhomeostasis of the endolymph, presumably by modulating Na, K-ATPase activity. Intense MR signal was also identified in spiral ganglion cells, the function of which remains to be determined.

Progressive encephalopathy in a Crohn's disease patient on long-term total parenteral nutrition: possible relationship to selenium deficiency.

The case of a patient with Crohn's disease complicated by progressive and irreversible encephalopathy, who had been on long-term total parenteral nutrition due to short bowel syndrome, is described. He initially experienced a disturbance of his vision, which was followed by various neurological symptoms during the next 3 years. These symptoms rapidly progressed until he finally developed consciousness disturbance. He also manifested erythrocytic macrocytosis, a low serum level of tri-iodothyronine and a high level of thyroxine. His blood levels of various trace minerals and vitamins were normal, except for selenium, which showed extremely low values. In addition, impaired plasma glutathione peroxidase activity was confirmed. After intravenous supplementation of selenium, macrocytosis, tri-iodothyronine and thyroxine values, and glutathione peroxidase activity all became normalized, yet he improved little neurologically. Our case suggests that long-term selenium deficiency may cause progressive and irreversible encephalopathy, and that careful monitoring of this mineral is necessary when an excessive period of total parenteral nutrition is being considered in the clinical setting.

Strial dysfunction in a melanocyte deficient mutant rat (Ws/Ws rat).

A homozygous mutant rat at the white spotting (Ws) locus showing a deficiency of melanocytes has recently been found (4, 5). The function and morphology of the inner ear of the Ws/Ws rat were examined by auditory brainstem response (ABR), endocochlear DC potential (EP), and electron microscopy. The mean ABR threshold of the Ws/Ws rat was significantly higher than that of the control +/+ rat. Most Ws/Ws rats showed no or very little EP. In electron microscopy, the stria vascularis of the Ws/Ws rat proved to be very thin and flat with poor interdigitation of marginal cells, and absence of intermediate cells. The organ of Corti appeared to be intact in both the +/+ rat and the Ws/Ws rat. These electrophysiological and morphological findings suggest that the Ws/Ws rat suffered from severe hearing loss caused by strial dysfunction.

Histopathological study on effects of potassium aspartate on the hypothalamus of rats.

Rats of various ages were treated orally or intraperitoneally with potassium aspartate. The dose required to induce hypothalamic lesion varied considerably by the age of animals and route of administration. Additional experiment, in which the animals were orally treated three times a day with potassium aspartate in dose levels between the maximum safety dose and minimum lesion-producing dose in the preceding single dose study, revealed no hypothalamic lesion at all in any animals of each age group. In this condition, the maximum safety dose was 3--5 times as large as that in single dosage administration experiment. Regarding the safety evaluation of potassium aspartate preparations, brief discussions on some points in extrapolation of the results of the present experimental study to the clinical use were made.