Reduced prepulse inhibition in rats with entorhinal cortex lesions

The relationship between the entorhinal cortex and prepulse inhibition (PPI) as well as dopaminergic participation in this relationship were examined. PPI is an operational measure of sensorimotor gating in which a robust response to a startling auditory pulse stimulus is inhibited when the stimulus is preceded by a weak prepulse. PPI can be measured in various species and is reduced in several neuropsychiatric disorders and in dopamine-activated rats. The entorhinal cortex was damaged bilaterally using ibotenic acid, and acoustic startle experiments were performed during treatment with haloperidol or saline on day 21 after the ibotenic acid injection. Neither this injection nor haloperidol affected the amplitude of the startle movement. Bilateral entorhinal cortex lesions reduced PPI, while haloperidol partially restored it. The entorhinal cortex and the sensorimotor gating system therefore may be related via dopaminergic circuits, possibly including the nucleus accumbens. Further, as the entorhinal cortex provides the major extrinsic synaptic input to the rat hippocampus, disease involvement of this region may severely affect cognition in various disorders including schizophrenia.     

Vitamin B6 protects primate retinal neurons from ischemic injury

Vitamin B6 derivatives protect the retinal neurons from excitotoxic injury in vitro. However, their in vivo role in a process involving excitotoxicity, such as ischemia, remains unknown. We studied potential protective effects of pyridoxal 5′-phosphate (PLP) and pyridoxal hydrochloride (pyridoxal) on the retinal neurons in a monkey model of transient global ischemia. Daily intravenous injections (15 mg/kg) of pyridoxal and PLP were performed for consecutive 10 days. On the sixth day, whole brain complete ischemia was produced by clipping the innominate and the left subclavian arteries for 20 min. The monkeys were sacrificed 5 days after ischemia and their retinas were processed for histological analysis. The ischemia induced a marked cellular injury in the retina as shown by the loss of ganglion cells and the reduction of thickness of the ganglion cell, inner plexiform, and inner nuclear layers. PLP significantly prevented the ganglion cell loss and the reduction of thickness of the ganglion cell layer. Pyridoxal significantly prevented the ganglion cell loss as well as the reduction of thickness of ganglion cell, inner plexiform and inner nuclear layers. These results suggest that PLP and pyridoxal counteract the postischemic neuronal death in the adult primate retina, offering a potential for a novel pharmacotherapy of retinal ischemic injury.     

Splenic atrophy in experimental severe acute pancreatitis

INTRODUCTION: In severe acute pancreatitis, immunologic impairment is supposed to be linked to the development of subsequent infectious complications. AIM: To examine alterations of spleen in rat experimental severe acute pancreatitis. METHODOLOGY: Severe necrotizing pancreatitis was induced by retrograde injection of 3% sodium deoxycholate into the biliopancreatic ducts of male Wistar rats. RESULTS: In the rats with pancreatitis 12 and 24 hours after the induction, splenic weights were significantly lower than those of sham-operated rats. Numbers of splenocytes were also significantly reduced simultaneously. By in situ nick-end labeling, DNA fragmentation enzyme linked immunosorbent assay (ELISA), and DNA electrophoresis, no apoptosis was detected on the splenocytes from the rats with pancreatitis 6, 12, and 24 hours after the onset. Peripheral lymphocytes in the rats with pancreatitis were significantly decreased 6, 12, and 24 hours after the onset compared with those in sham-operated rats. With antecedent splenectomy, peripheral lymphocyte counts 12 hours after the onset were significantly lower than those in rats who had not undergone splenectomy. Moreover, nuclear fragmentation was noted, and DNA fragments were significantly increased in peripheral lymphocytes at 6 hours in sodium deoxycholate pancreatitis. CONCLUSION: These results indicate that splenic atrophy resulting from splenocyte reduction occurs in rat experimental severe acute pancreatitis. It is suggested that splenocytes are recruited into systemic circulation in response to peripheral lymphocyte reduction as a result of apoptosis.     

Developmental change of Moro reflex studied with a three-dimensional motion analysis system

We evaluated developmental change of the reaction time of the Moro reflex from birth to three months of age using a three-dimensional motion analysis system (ToMoCo-VM:Tousou system). The reaction time was the shortest in one-month-old babies and became successively prolonged in two and three-month-old babies, showing a U-shaped pattern. The three phase of the Moro reflex, as defined by McGraw, changed with advancing age. The reaction time changed monthly. At the same monthly age, the reaction time was the same irrespective of the phase.     

Psychological stress increases human T cell apoptosis in vitro

OBJECTIVES: Recent studies have shown that apoptosis is involved in stress responses. The present study examined if stressors increase in vitro apoptosis of peripheral blood T lymphocytes in a dose-dependent manner. METHODS: Daily subjective stress was quantitatively analyzed in 40 nonsmoking men with a daily hassles questionnaire. Apoptosis of T lymphocytes was measured by flowcytometry using Annexin V/PI double staining method after 0, 12, and 24 h of culture in the presence or absence of dexamethasone (DEX). Using a cross-sectional design, the current study examined the relationship between stress and in vitro apoptosis of T cells. RESULTS: Results showed that apoptosis of T lymphocytes in vitro has a significant correlation with stress and age. Stress was positively correlated with percentage of apoptosis in T cells after 12 h of culture, irrespective of DEX treatment. Age was positively correlated with the percentage of T cell apoptosis after 0 and 12 h of coculture with DEX. CONCLUSIONS: These results indicate that age-related apoptosis and stress-related apoptosis of T cells are modulated through different mechanisms. This is the first study to show that in vitro lymphocyte apoptosis is influenced by daily stress in a dose-dependent manner.     

Undifferentiated carcinoma with osteoclast-like multinucleated giant cells arising in an ovarian mature cystic teratoma

Malignant transformation is an unusual complication of mature cystic teratomas. Squamous cell carcinomas and adenocarcinomas are predominant among these malignant tumors. We present a 70-year-old Japanese woman with a giant ovarian tumor (30 x 23 x 9 cm) and multiple peritoneal dissemination. The huge tumor was filled with necrotic and fatty tissue and coagula accompanied with hair balls histologically diagnosed as undifferentiated carcinoma with multinucleated giant cells arising in an ovarian mature cystic teratoma. The residual disseminated tumors grew very rapidly and occupied the whole abdominal cavity again 3 weeks after the surgery. The patient died 5 weeks after the operation.     

Contribution of lipid dynamics on the inhibition of bovine brain synaptosomal Na+-K+-ATPase activity induced by 4-hydroxy-2-nonenal

The effects of lipid hydroperoxide degradation products, such as 4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA), on bovine brain synaptosomal ATPase activities and their membrane lipid organization were examined. When the synaptosomes were treated with HNE, this resulted in the decrease of Na(+)-K(+)-ATPase activity with the loss of sulfhydryl (SH) groups in the membrane proteins. In contrast, MDA treatment of the synaptosomes did not induce an appreciable decrease in the ATPase activity or a loss of SH groups. The decreases in ATPase activity and SH content by treatment with HNE were also observed, as a Na+-K+-ATPase preparation was used in place of the synaptosomes. On the other hand, HNE had very little effect on synaptosomal Ca2+- and Mg2+-ATPase activities. The results of the kinetic analysis of the Na+-K+-ATPase activity indicated that the decrease in the activity by HNE-modification is due to a decreased affinity for the substrate. ATP completely protected the ATPase from the HNE attack. Modification of the synaptosomes with HNE caused a decrease in the membrane lipid fluidity near the lipid/water interface, not the lipid layer interior. In addition, it was found that there is a good relationship between the lipid fluidity and the Na+-K+-ATPase activity under the presence of various concentrations of HNE, suggesting that the lipid dynamics are closely related to HNE-induced inhibition of the ATPase activity. On the other hand, MDA did not induce change in the membrane lipid fluidity. HNE and MDA are mainly incorporated into the lipid and protein fractions in the synaptosomal membranes, respectively. Based on these results, we proposed a possible mechanism of HNE-induced inhibition of synaptosomal Na+-K+-ATPase activity associated with alterations in the membrane lipid organization.     

Effects of Hange-koboku-to (Banxia-houpo-tang) on neuropeptide levels in human plasma and saliva

Hange-koboku-to (Banxia-houpo-tang), a Chinese herbal (Kampo) medicine, has been used for improvement of hoarse voice, something foreign body sensation in the throat and/or esophagus, and swallowing reflex, among other conditions. One of the mechanisms of the empirical effects is assumed to be due to local changes in neuropeptide levels locally. We investigated the effects of Hange-koboku-to on neuropeptides, calcitonin gene-related peptide (CGRP), substance P, somatostatin, and vasoactive intestinal peptide (VIP) in plasma and saliva, as well as on salivary secretion in healthy subjects. A single oral administration of Hange-koboku-to caused significant increases in substance P-immunoreactive substance (IS) (40 min) in plasma, and slightly increased in CGRP-IS and somatostatin-IS in plasma compared with placebo. In saliva neuropeptides, Hange-koboku-to caused significant increases in substance P-IS (20 min) and somatostatin-IS (40, 60 min), and a slight increase in VIP-IS. However, a single Hange-koboku-to stimulation did not have a significant effect of sialosis volume. These results seem to suggest that Hange-koboku-to improves hoarse voice, something foreign body sensation in the throat and esophagus, and swallowing reflex disorder, by stimulation of neuropeptidergic nerves locally.