Immunohistochemical analysis of equine pulmonary granular cell tumours

Histopathological and immunohistochemical examinations were made on four female horses aged 9-12 years with pulmonary granular cell tumours (GCTs). The tumours, which were multiple, of varying size, firm and off-white in colour, surrounded the bronchi and bronchioles. Metastatic lesions were not detected. The tumour cells had abundant eosinophilic cytoplasm filled with prominent coarse eosinophilic granules. Immunohistochemically, these tumour cells reacted uniformly with vimentin and S100 antibodies. Most were immunolabelled by antibodies against glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) and protein gene product 9.5 (PGP9.5), and a few cells were positive with Leu7 antibody. However, the tumour cells did not react with antibodies against neurofilament protein (NF), cytokeratin (CK), chromogranin, alpha1 antichymotrypsin (AACT), myoglobin, desmin, alpha-actin or alpha-smooth muscle actin (alpha-SMA). These immunohistochemical properties of tumour cells support the hypothesis that equine pulmonary GCTs are derived from Schwann cells of the peripheral nervous system in peribronchial and peribronchiolar tissues. GFAP, MBP, Leu7 and PGP9.5 antibodies should help to distinguish equine granular cell tumours from other tumours.

[Efficiency of bispectral index in anesthetic management of a patient with hypothyroidism]

A 72-year-old, female patient with severe hypothyroidism underwent tracheostomy using deltopectral flap. During the anesthetic management, we assessed the hypnotic level using the bispectral index and regulated the dose of general anesthetics to maintain the bispectral index at about 50. The general anesthetics caused a marked cardiovascular depression, but the condition was treatable with the intravenous administration of dopamine. Using these methods, we could anesthetize this patient safely without a prolonged awakening time from general anesthesia. Although the anesthetic requirement for patients with hypothyroidism is generally thought to be decreased, there is no practical index by which we can estimate the optimal dose of anesthetic agents for these patients. This case report shows that the assessment of the hypnotic level by the bispectral index can be utilized as an efficient index to determine the optimal dose of general anesthetics for patients with hypothyroidism.

Reduced production of lactate during hypoxia and reoxygenation in astrocytes isolated from stroke-prone spontaneously hypertensive rats

Lactate production and expressions of monocarboxylate transporter 1 (MCT1) and lactate dehydrogenase (LDH) mRNA after hypoxia and reoxygenation (H/R) were examined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) using astrocytes in culture isolated from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). The basal production of lactate in SHRSP was the same as that observed in WKY. In contrast the lactate levels in SHRSP at 1 and 6 h of reoxygenation after hypoxia were significantly lower than those observed in WKY. In addition LDH and MCT1 mRNA expressions in SHRSP were significantly less strong compared with those in WKY during H/R. These findings indicate that decreased production and slow transport of lactate in SHRSP astrocytes are involved in neuronal energy depletion and possibly encourage neuronal damage, although hereditary weakness of cortical neurons is also related to cell death during H/R.

Angle-resolved photoemission study of insulating and metallic Cu-O chains in PrBa2Cu3O7 and PrBa2Cu4O8

We compare the angle-resolved photoemission spectra of the hole-doped Cu-O chains in PrBa2Cu3O7 (Pr123) and in PrBa2Cu4O8 (Pr124). While, in Pr123, a dispersive feature from the chain takes a band maximum at k(b) (momentum along the chain) approximately pi/4 and loses its spectral weight around the Fermi level, it reaches the Fermi level at k(b) approximately pi/4 in Pr124. Although the chains in Pr123 and Pr124 are approximately 1/4 filled, they show contrasting behaviors: While the chains in Pr123 have an instability to charge ordering, those in Pr124 avoid it and show an interesting spectral feature of a metallic coupled-chain system.

Assessment of in vivo oxidative stress in hypertensive rats and hypertensive subjects in Tanzania, Africa

Oxidative stress has been reported to be involved in not only cardiovascular diseases but in hypertension, which is a major risk for cardiovascular diseases. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) has been recognized as a sensitive biomarker of oxidative DNA damage and also of oxidative stress. In the present study, we assessed the oxidative stress in human subjects with hypertension and in hypertensive rats. In stroke-prone spontaneously hypertensive rats at the age of 14 weeks, the excretion of urinary 8-OHdG was significantly (p < 0.05) increased compared with that in age-matched normotensive Wistar-Kyoto rats. Next, we investigated the relationship between oxidative DNA damage and cardiovascular risk factors among Tanzanians aged 46-58 years in a population study carried out in 1998 in at Dar es Salaam, Tanzania, according to the WHO-CARDIAC Study Protocol. Sixty subjects (male/female, 28/32) were selected by SPSS Base 8.0 from those who completed a 24-h urine collection. The 24-h urinary 8-OHdG of the hypertensive subjects (SBP > or =140 mmHg and/or DBP > or =90 mmHg) was significantly (p < 0.05) higher than that of the normotensive subjects (SBP <140 mmHg and DBP <90 mmHg) after adjusting for age and gender (Hypertensives: 17.31 +/- 2.0 ng/mg creatinine, n=38; Normotensives: 10.10 +/- 2.64 ng/mg creatinine, n=22). Oxidative stress was thought to be involved in hypertensive subjects and in hypertensive rats.

Altered gene expressions during hypoxia and reoxygenation in cortical neurons isolated from stroke-prone spontaneously hypertensive rats

The expressions of Bcl-2, thioredoxin (TRX) and cytochrome c oxidase III (CO III) mRNAs after hypoxia and reoxygenation (H/R) were examined by quantitative reverse transcription-polymerase chain reaction using cultured cortical neurons isolated from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar Kyoto rats (WKY). The differences in gene expressions of Bcl-2, TRX and CO III mRNA between SHRSP and WKY were most remarkable at 30 min of oxygen stimulation, and the expressions of these genes were significantly lower in SHRSP compared with those in WKY. These findings pointed out that redox regulatory function and energy metabolism in SHRSP neurons were markedly reduced by oxygen stimulation after hypoxia, and such changes may be involved in neuronal vulnerability.

Consideration of the role of antigenic keratan sulphate reacting to a 1/14/16H9 antibody as a molecular marker to monitor cartilage metabolism in horses

The role of keratan sulphate (KS) as a marker of cartilage metabolism was evaluated by using an in vitro model of equine articular cartilage. Articular cartilage was harvested from clinically healthy 6-month-old foals (n=3). Chondrocytes were centrifuged and cultured as pellets. Chondrocyte pellets were stimulated by insulin-like growth factor (IGF)-Ialpha or interleukin (IL)-1alpha for 2 weeks. The sulfated glycosaminoglycans (GAG) and antigenic KS concentrations in the culture media were measured by a 1,9-dimethyl-methylene blue (DMMB) colorimetric assay and an inhibition ELISA using a 1/14/16H9 antibody, respectively. Concentration of GAG was significantly increased in the media of pellets stimulated by both IGF-Ialpha and IL-1alpha. Antigenic KS concentration was significantly increased in those stimulated by IL-1alpha, while no significant change was found in those stimulated by IGF-Ialpha. A high correlation between GAG and antigenic KS concentrations was found in the media of pellets stimulated by IL-1alpha (r=0.87), but not in those stimulated by IGF-Ialpha (r=0.43). The results suggest that the concentration of antigenic KS reacting to 1/14/16H9 mirrors the GAG concentration during the stage of cartilage catabolism, but not during the cartilage anabolic stage. The concentration of antigenic KS reacting to 1/14/16H9 antibody in biological fluids could therefore be a useful marker to further understand principally the catabolic and slightly the anabolic process of articular cartilage metabolism.

Specific binding and effects of dehydroepiandrosterone sulfate (DHEA-S) on skeletal muscle cells: possible implication for DHEA-S replacement therapy in patients with myotonic dystrophy

Dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) are the most abundant steroidal products and major circulating steroids in humans. The serum concentrations of DHEA-S are lower in patients with myotonic dystrophy (DM) than normal controls, and possible improvement of myotonia and muscle weakness was recently reported following DHEA-S replacement therapy. However, the molecular mechanism of action of DHEA-S remains unknown. To understand the reported anti-DM action of DHEA-S, we investigated DHEA-S binding in skeletal muscle cells in vitro. We identified two populations of DHEA-S binding sites (Kd = 5-9 microM and 35-40 microM) in C2C12 myocytes. Similar binding sites were also identified in human skeletal muscles. The Kd value of the high-affinity site was within the range of serum concentrations of DHEA-S in adult humans. Our results suggest that DHEA-S might act directly on skeletal muscles under normal physiological conditions in humans.

Vitamin E prevents apoptosis in hippocampal neurons caused by cerebral ischemia and reperfusion in stroke-prone spontaneously hypertensive rats

Cerebral ischemia followed by oxygen reperfusion induced apoptosis in hippocampal neurons in stroke-prone spontaneously hypertensive rats (SHRSP) but not in Wistar Kyoto rats. Oxygen radicals were involved in reoxygenation injury after hypoxia in hippocampal slices. Vitamin E inhibited the reoxygenation injury in cultured cortical neurons. In addition, the temporal cortices in Alzheimer's disease have increased sensitivity to oxygen radicals, and Vitamin E slowed the progression of the disease. Thus we fed Wistar Kyoto and SHRSP rats either a normal diet or a high Vitamin E diet for 3 weeks. We measured Vitamin E concentrations of plasma and brain by applying the HPLC method. Vitamin E increased its concentration in plasma, cerebral cortex, and hippocampus (p < 0.01) during a 3-week pretreatment. In addition, we clipped both common carotid arteries in these rats for 30 minutes. After the blocking, the rats were reperfused for 6 and 9 days, respectively, and then killed. We cut the brains coronally, removed the hippocampal CA1 regions, and examined the neurons using an electron microscope. SHRSP rats with normal cerebral circulation had 30.4+/-8.0 apoptotic neurons per 1000 neurons. Cerebral ischemia followed by 6 and 9 days of reperfusion, respectively, increased apoptotic neurons in SHRSP rats fed a normal diet (6 days: 542.5+/-154.1 per 1000 neurons; 9 days: 657.5+/-110.2 per 1000 neurons). In contrast, apoptotic neurons in SHRSP rats fed a high Vitamin E diet were significantly (p < 0.01) small in number (6 days: 41.3+/-27.5 per 1000 neurons; 9 days: 35.5+/-19.7 per 1000 neurons) even though the rats were treated in the same way. These data demonstrate that oxygen radical generation occurs after reperfusion and that free radicals heavily damage the neurons in SHRSP rats. Vitamin E reacts with the radicals and prevents neuronal apoptosis caused by cerebral ischemia and reperfusion. Therefore, Vitamin E seems to be an important agent in lowering radical damage to hippocampal neurons.

[A case of atypical Miller Fisher syndrome associated with antiphospholipid antibodies]

We report a 56-year-old man with external ophthalmoplegia and ataxic gait following a diarrhea, being diagnosed atypical Miller Fisher syndrome (FS). On admission, he had severe diplopia and bilateral external ophthalmoplegia were observed. The deep tendon reflexes were decreased on the right upper extremity. He could not walk straight and his tandem gait was impaired. Serum IgG anticardiolipin antibody (aCL) and APTT-lupus anticoagulant (LA) were found to be increased. The serum of the patient had low titer of anti-GQ 1 b and anti-GM 1 antibodies. After the first immunoadsorption therapy, his ophthalmoplegia was improved moderately, but peripheral facial palsy appeared. He was treated with immunoadsorption again, then all neurologic symptoms improved and a follow-up study revealed normalized aCL and LA titers. There have been no previous reports of FS associated with antiphospholipid antibody. The low titer of serum anti-GQ1b and anti-GM 1 antibodies in this patient suggests that the antiphospholipid antibodies, such as aCL and LA, may be linked to the pathogenesis of FS.

Genetic vulnerability of cortical neurons isolated from stroke-prone spontaneously hypertensive rats in hypoxia and oxygen reperfusion

Severe hypertension and cerebrovascular diseases develop in stroke-prone spontaneously hypertensive rats (SHRSP). Cortical neurons from SHRSP are more vulnerable than those from Wistar Kyoto rats (WKY) to the effects of nitric oxide (NO)- and N-methyl-D-aspartate (NMDA)-mediated neurotoxic agents. Growth factors, idebenone, and nilvadipine (a Ca2+ channel blocker) can reduce neuronal damage caused by hypoxia or neurotoxic agents. This study was designed to determine 1) whether cortical neurons from SHRSP are more vulnerable than those from WKY and 2) whether neuronal damage is minimized by the so-called neuroprotective agents in cells exposed to hypoxia and oxygen reperfusion. We demonstrated that 6 to 24 h of hypoxia did not increase cell death in either WKY or SHRSP, whereas 36 h of hypoxia significantly increased cell death in SHRSP (p < 0.01). Furthermore, 6 to 36 h of hypoxia and 1.5 to 5 h of reperfusion heavily damaged cells from both strains of rats, and most cells became apoptotic or necrotic. We also verified that the ability to protect neurons in hypoxia and oxygen reperfusion was as follows: idebenone > insulin-like growth factor-1 (IGF-1) > nilvadipine. These data indicate that oxygen radical generation occurs and the free radicals heavily damage neurons in hypoxia and oxygen reperfusion. SHRSP neurons are weaker than WKY neurons in these conditions. Furthermore, we surmise that idebenone, an antioxidant, decreases free radicals, and IGF-I attenuates p53-mediated apoptosis and thereby prevents cell death. We conclude that antioxidants are more potent than IGF-1 in protecting cortical neurons from damage caused by hypoxia and oxygen reperfusion, although both are very useful in minimizing damage to cortical neurons.

[Dorsal root identification using spinal endoscopy and electro-physiology]

We aimed to develop a method of accurately identifying the dorsal root for the corresponding peripheral afferent nerve under endoscopic observation. We developed an endoscope with an external diameter of 1.8 mm. After small laminectomy on the lower thoracic vertebrae, we inserted this endoscope carefully into the epidural and then subarachnoid spaces. We observed structures in these spaces with the endoscope. We tried to determine the spatial relationship between these electrodes and dorsal root. After identifying each space, we inserted two electrodes into the visualized space to record evoked potentials; a bipolar electrode (protocol 1) and a catheter-type eight polar electrode (protocol 2). Each pole could be distinguished by marks. To stimulate peripheral nerves, we inserted needle-type electrodes into Th 10, 11 and 12 intercostal nerves. We attempted to record potentials from dorsal surface of the cord generated by intercostal nerve stimulus. Protocol 1: We moved the position of the bipolar recording electrodes between Th 9 and L 1 by 1 cm increment, and obtained evoked potentials correspondingly. Protocol 2: We chose the neighboring pairs of poles sequentially from the tip of the catheter for bipolar recording. At the end of each experiment, we dissected the animal and checked the intercostal nerve originating from the root. With the endoscope, we could clearly observe structures in the epidural and subarachnoid spaces. We could record evoked potentials from the dorsal spinal cord with the electrodes located either in epidural or in subarachnoid spaces. Shapes of evoked potentials changed characteristically according to the relative position between the root and the electrode. The largest potentials were obtained when the electrode was nearest to the dorsal root, of which the peripheral nerve was being stimulated. By combining endoscopy with the electrophysiological technique, we could accurately identify the dorsal roots for the corresponding peripheral afferent nerves. This method may be used for the selective dorsal root blockade under the visual field.

Zonal differences in effects of HGF/SF and EGF on DNA synthesis in hepatocytes under fed or starved conditions

Zonal differences of DNA synthesis in hepatocytes induced by hepatocyte growth factor and/or scatter factor (HGF/SF) and epidermal growth factor (EGF) were investigated using male Wistar rats under fed or starved conditions. Overall, DNA synthesis was greater in fed rats than in starved rats. The predominance of EGF in periportal hepatocytes (PPH) on zonal DNA synthesis was reversed by starved conditions, but the predominance of HGF/SF on zonal DNA synthesis in perivenous hepatocytes (PVH) was not influenced by nutritional conditions. 125I-labeled EGF and 125I-labeled HGF/SF-receptor binding studies revealed no significant difference between PPH and PVH in starved or fed rats. To investigate the mechanism of the signal transduction pathway, we used genistein, an inhibitor of tyrosine kinase. Genistein had different effects on zonal difference in EGF and HGF/SF. In EGF, 1 microgram/ml genistein abolished zonal differences, but in HGF/SF 1 microgram/ml genistein did not abolish zonal differences. These data suggest that, in contrast to HGF/SF, zonal difference of DNA synthesis by EGF was dependent on nutritional conditions and DNA synthesis induced by HGF/SF and EGF might be related to tyrosine kinase, but the influence of tyrosine kinase on DNA synthesis was different between HGF/SF and EGF.

Vitamin E prevents apoptosis in cortical neurons during hypoxia and oxygen reperfusion

Cerebral ischemia followed by oxygen reperfusion induces apoptosis in hippocampal neurons in stroke-prone spontaneously hypertensive rats (SHRSP) but not in Wistar Kyoto rats (WKY). The overproduction of oxygen-free radicals that occurs in the tissues of SHRSP is implicated in reoxygenation injury after hypoxia. Antioxidants inhibit reoxygenation injury in hippocampal slices, and temporal cortices in Alzheimer's disease increase sensitivity to oxygen-free radicals. Because this sensitivity may contribute to the development of the disease, we have studied hypoxia and oxygen reperfusion using cortical neurons isolated from WKY and SHRSP (at 15 days of gestation). We have tried to determine whether cortical neurons are damaged under these conditions, and whether neurons from SHRSP are more vulnerable than those from WKY. We have tried also to verify whether neuronal damage is minimized by vitamin E using the following techniques: (a) Trypan blue staining, (b) in situ staining of apoptosis, (c) ultrastructural examination, and (d) measurement of lactic dehydrogenase (LDH) activity in the bathing medium. Furthermore, we have examined the mechanisms involved in the development of neuronal damage and have studied ways of minimizing it. We demonstrated that 36 hours of hypoxia significantly increased the rate of cell death in SHRSP (p < 0.01), although 12 to 24 hours of hypoxia did not increase cell death in either WKY or SHRSP. In addition, 6 to 36 hours of hypoxia and 1.5 to 5 hours of oxygen reperfusion heavily damaged cells of both WKY and SHRSP, and most became apoptotic or necrotic. In contrast, cells incubated with 50 to 300 microg/ml of vitamin E remained intact, although 10 to 20 microg/ml of vitamin E did not totally preserve the cells. Moreover, vitamin E protected the neurons from high concentrations of sodium nitroprusside (nitric oxide donor) in a dose-dependent manner. Vitamin E, when added to the cells, increased in concentration in a time-dependent manner over a 24-hour period and in a dose-dependent manner below 200 microg/ml, and it was detected mostly in the mitochondria. We also demonstrated that serial treatments with allopurinol (a xanthine oxidase inhibitor) or superoxide dismutase preserved neurons during hypoxia and oxygen reperfusion. These data indicate that SHRSP neurons are weaker than WKY neurons in long-term hypoxia; oxygen radical generation occurs in the early minutes after reperfusion, and then the oxygen-free radicals cause heavy damage to the cells; and antioxidants including vitamin E react with the radicals, thereby preventing apoptosis and necrosis. Therefore, antioxidants appear to be the most important agents in lowering oxygen-free radical damage in cortical neurons.

Measurement of serum and synovial fluid keratan sulphate and antibody to collagen type II in equine osteoarthritis

Keratan sulphate (KS) concentration and anticollagen type II antibody levels were measured in the serum and synovial fluid (SF) of clinically normal horses and horses with osteoarthritis (OA). Serum KS in OA was significantly higher than that in normal horses, while no significant difference was found in KS levels of SF between normal and OA. Assays of antibody to collagen type II showed no significant increase in sera and SF of OA. It was suggested that levels of serum KS would be of value in the pathological detection of OA in the joint, although there was no evidence that the measurable autoimmunity to collagen antigens would reflect the process of OA.

Serum copper and ceruloplasmin activity at the early growing stage in foals

Serum concentrations of copper (Cu), zinc (Zn), manganese (Mn), calcium (Ca) and inorganic phosphorus (P), as well as antigenic ceruloplasmin (Cp) and oxidase activity as a functional index for copper metabolism, were measured in 10 foals (5 males and 5 females) and their dams. Samples were harvested from the foals within 1 wk after birth and monthly from 1 to 17 mo of age. Samples were collected from their dams in the perinatal period (monthly from 2 mo before delivery to 5 mo postpartum). Serum oxidase activity, antigenic Cp and Cu in foals were extremely low at 1 wk. Serum Cp had the lowest value of 17.0 +/- 8.0 (mean +/- SD) mg/dL within the 1st wk, then increased rapidly up to 43.7 +/- 5.8 mg/dL at 1 mo, and maintained this level until the 17th mo. Serum Zn in foals had the highest value of 73.2 +/- 13.1 micrograms/dL within 1 wk, then decreased to 38.3 +/- 5.9 micrograms/dL by 17 mo. Serum Mn, Ca and P in mares were almost stable and within established reference ranges for our laboratory in the perinatal period, and these values in foals were also in the normal range. Even on appropriate feeding, serum Cu, Cp and oxidase activity were quite low a few weeks after birth, while a higher proportion of Cp-binding copper was found in the foals. This might be caused by the limited synthesis of ceruloplasmin in this period. These data suggest that newborn foals are in a critical situation of marginal copper status in the early stage of growth.

Astrocyte-conditioned medium induces blood-brain barrier properties in endothelial cells

1. We evaluated the induction of endothelial barrier functions by the type 1 astrocyte-derived supernatant in culture using horseradish peroxidase (HRP) as a parameter. 2. A gel filtration fraction (molecular weight 16-20 kDa) of type 1 astrocyte-derived supernatant reduced plasmalemmal vesicles and induced tight junctions in endothelial cells. 3. In addition, this fraction promoted the uptake of [3H]-glucosamine by endothelial cells. This cell activity disappeared after heating at 95 degrees C for 10 min and was sensitive to trypsin. 4. These results suggest that a type 1 astrocyte-derived protein factor(s) promotes proteoglycan synthesis with a resultant increase in charge selectivity in endothelial cells and plays an important role in the induction of blood-brain barrier functions.

Faulty induction of blood-brain barrier functions by astrocytes isolated from stroke-prone spontaneously hypertensive rats

1. It has been suggested that astrocytes prompt the induction of blood-brain barrier (BBB) functions in cerebrovascular endothelial cells. 2. In the present study we have tried to elucidate the genetic differences between astrocytes isolated from Wistar-Kyoto (WKY) control rats and astrocytes isolated from stroke-prone spontaneously hypertensive rats (SHRSP). 3. We show that endothelial cells develop tight junction-like structures, a reduction in vesicular transport and high electrical resistance when they are co-cultured with astrocytes isolated from WKY rats. In contrast, SHRSP astrocytes have less of an ability to induce BBB functions than do WKY astrocytes. 4. In addition, we demonstrate that SHRSP astrocytes produce enormous quantities of lactic acid when cerebral ischaemia develops. The decrease in pH causes astrocyte swelling and damages BBB functions. 5. Consequently, we reason that genetically weak functions in astrocytes cause disruptions of BBB function and result in widespread cerebral lesions in SHRSP.