The polymorphic 43Thr bcl-2 protein confers relative resistance to autoimmunity: an analytical evaluation

We have found a novel polymorphic (Ala43Thr; ACC-->GCC) bcl-2 allele in a Japanese population. An in vitro expression study with a mouse IL-7-dependent pre-B cell line has revealed that inhibition of the programmed cell death function of 43Thr bcl-2 protein is suppressed compared with that of normal 43Ala bcl-2 protein. Since bcl-2 expression in B-lymphoid cells elicits autoimmune disease in mice, we have investigated the possibility of whether a bcl-2 polymorphism has a different susceptibility to autoimmune disease. To evaluate the clinical impact of this polymorphism, the frequency of bcl-2 polymorphism was investigated in 221 children with insulin-dependent diabetes mellitus (IDDM), 237 adults with autoimmune disease (105 with rheumatoid arthritis, 57 with systemic lupus erythematosus, 55 with Sjögren's syndrome, and 20 others), and 290 healthy Japanese children and adults. The frequency of the 43Thr bcl-2 allele, either homozygous or heterozygous, was 14.5% in normal controls, 6.8% (P<0.01) in children with IDDM, and 8.0% (P<0.025) in adults with autoimmune disease. These results suggest that the 43Thr allele of bcl-2 confers resistance to autoimmune disease. The different anti-apoptotic function resulting from the different expression of bcl-2 protein in lymphocytes seems to be associated with the development of autoimmune disease, indicating that the bcl-2 gene affects human autoimmune disease.

Measurement of the extracellular H2O2 in the brain by microdialysis

This paper reports on the protocol for the determination of H2O2 in the brain using in vivo microdialysis coupled with fluorometry of dichlorofluorescin oxidation. We applied this protocol to monitor changes in the concentration of H2O2 in the brain, in vivo, during ischemia and reperfusion. Using this method, changes in the level of H2O2 in the brain during ischemia and reperfusion were effectively determined. The present protocol provides a novel tool to study the production of reactive oxygen species in the brain.

Ischemic preconditioning suppresses the noradrenaline turnover in the rat heart

OBJECTIVE

The mechanism by which ischemic preconditioning protects the heart is presumed to be related to the reduction of energy consumption during a subsequent myocardial infarction. Since the sympathetic nervous system enhances cardiac function and energy consumption, we investigated the relation between ischemic preconditioning and the turnover rate of noradrenaline (NA) in the rat heart.

METHODS

The effect of 3 cycles of 5-min occlusions of the rat left coronary artery on changes in arterial blood pressure and heart rate provoked by a subsequent 30 min of ischemia were examined until 60 min after reperfusion. The effect of 3 cycles of occlusions on the infarct size was also evaluated 60 min after reperfusion by comparing the infarcted area with the area at risk in these animals (6 per preconditioned and sham-operated group). The tissue concentration of NA during sustained ischemia was determined in the left ventricle, the intraventricular septum, and the right ventricle in the preconditioned and sham-operated groups. Changes in the turnover rate of NA after 3 cycles of occlusions were also evaluated by assessing the alpha-methyl-p-tyrosine-induced depletion of NA (n = 7 per group).

RESULTS

A series of transient occlusions reduced the infarct size 60 min after a sustained ischemia for 30 min. Arterial pressure and heart rate were not affected. The concentration of NA was decreased in the left ventricle 60 min after the onset of sustained ischemia in both the preconditioned and sham-operated groups. The treatment with alpha-methyl-p-tyrosine decreased the NA concentration in all regions of the heart in the sham-operated group after 60 min. However, the treatment with alpha-methyl-p-tyrosine did not deplete the NA concentration in both the occluded and nonoccluded regions in the preconditioned group.

CONCLUSIONS

Transient ischemia ameliorated the heart injury induced by a subsequent sustained ischemia, as assessed histologically. The activity of the sympathetic nervous system in all regions of the heart was reduced by transient ischemia in the left coronary vascular bed. These findings suggest that the inhibition of the sympathetic nervous system by the treatment of ischemic preconditioning takes part in the cardiac protection.

Characterization of the 3' untranslated region of mouse DNA topoisomerase IIalpha mRNA

Expression of DNA topoisomerase IIalpha protein varies through the cell cycle with its peak in G2/M. This cell-cycle-dependent expression depends on changes in topoisomerase IIalpha mRNA stability as well as promoter activity. We isolated the 3' genomic region of the mouse topoisomerase IIalpha gene and investigated whether or not the 3' untranslated region (UTR) of the topoisomerase IIalpha mRNA participates in the cell-cycle-dependent mRNA stability. Interestingly, genomic- and RT-PCR analyses revealed that the topoisomerase IIalpha 3' UTR is formed via splicing in mouse, but not in human and hamster. Comparison of the mouse 3' region with the human and hamster regions suggests that this mouse-specific splicing has resulted from an accidental acquisition of the consensus 5' splice site. The minority of the non-spliced topoisomerase IIalpha 3' UTR in mouse was confirmed by Northern blot analysis. We performed transient expression assays using luciferase constructs with the mouse topoisomerase IIalpha 3' genomic region, or the major spliced form of the 3' UTR. However, neither construct affected the cell-cycle-dependent expression of the reporter gene driven by the topoisomerase IIalpha promoter. Our results strongly suggest that the mouse topoisomerase IIalpha 3' UTR by itself is not involved in the cell-cycle-dependent mRNA stability.

Ex vivo malignant glioma cells are sensitive to Fas (CD95/APO-1) ligand-mediated apoptosis

Fas (also known as CD95/APO-1) is a cell surface receptor and member of the tumor necrosis factor receptor superfamily which mediates apoptosis in sensitive cells upon oligomerization by specific antibodies or by its ligand (FasL). Recently, human glioma cell lines were found to be susceptible to Fas-mediated apoptosis triggered by alpha-Fas antibodies. However, whether the Fas system can also be targeted in ex vivo high grade gliomas is at present unknown. In the present investigation, alpha-Fas antibodies and FasL were tested in short-term monolayer cultures or in colony forming assays established from freshly resected tumors of patients with anaplastic astrocytomas (WHO grade III) and glioblastoma multiforme (WHO grade IV). Anti-Fas antibodies induced only moderate apoptosis in four of the 19 tested glioma cell cultures. This contrasts FasL which induced apoptosis in all of the 19 tumor cell cultures analyzed. Mean cytotoxicity of glioma cell cultures treated for 48 h with alpha-Fas antibodies or FasL was 9.6% and 44.3%, respectively. Irrespective of whether alpha-Fas antibodies or FasL were used, pretreatment with recombinant hu (rhu) IFN-gamma and rhuTNF-alpha for 48 h did not sensitize glioma cells to Fas-mediated cytotoxicity. The long-term effect by FasL on tumor colony formation was more striking. FasL treatment resulted in more than 90% inhibition of clonal tumor cell growth of all the eight high grade gliomas analyzed. These results suggest that Fas targeting by FasL but not by alpha-Fas antibodies may provide a promising approach for locoregional glioma treatment.

SPET study of verbal fluency in schizophrenia and epilepsy

BACKGROUND

The association between temporal lobe epilepsy and schizophrenia suggests that the critical abnormality may be pathology within the temporal lobes. People with schizophrenia-like psychosis of epilepsy (SLPE) provide a useful group in which to examine the importance of temporal and frontal lobe dysfunction in schizophrenia.

METHOD

A verbal fluency activation paradigm and a 99mTc HMPAO SPET were used to study frontotemporal function in people with SLPE (n = 12), schizophrenia (n = 11) and epilepsy (n = 16).

RESULTS

People with SLPE differed from both other groups by showing lower blood flow in the left superior temporal gyrus during performance of a verbal fluency task compared with a word repetition task (F = 5.4, P = 0.01). During the verbal fluency task people with primary schizophrenia showed a greater increase in blood flow in anterior cingulate (F = 4.5, P = 0.02) than the other two groups. There were no between-group differences in frontal brain regions.

CONCLUSION

Our findings support an association between left temporal lobe abnormality and SLPE. The different patterns of activation observed in people with primary schizophrenia and SLPE suggests that different pathophysiological mechanisms may operate in these two groups. In SLPE the pathophysiology may be relatively confined to the dominant temporal lobe.

Predictive value of interictal epileptiform discharges during non-REM sleep on scalp EEG recordings for the lateralization of epileptogenesis

PURPOSE

EEG recording during sleep is widely used in the assessment of epilepsy, particularly in candidates for surgery, yet the diagnostic value of this procedure is not well established. We evaluated the predictive reliability of interictal epileptiform discharges (IEDs) for localization in presurgical patients with temporal lobe epilepsy (TLE) during non-REM sleep.

METHODS

Preoperative scalp EEG recordings with waking and sleep states were assessed in 83 patients with TLE in whom localization of the epileptogenic zone was subsequently confirmed by successful surgical treatment (patient seizure-free >1 year).

RESULTS

The accuracy of EEG recordings for prediction of lateralization significantly changed from 51.8% during waking to 78.3% during sleep. After exclusion of patients who showed no discharges, the predictive value changed from 74.1 to 86.7%. However, in patients in whom the waking scalp EEG lateralized incorrectly, no improvement in reliability was achieved by sleep recording.

CONCLUSIONS

Our results suggest that IEDs occurring in non-REM sleep provide more accurate information for lateralization of epileptogenesis than do those occurring during waking. This gain of diagnostic information was obtained in patients who showed either bilateral or no discharges in waking records, because unilateral discharges arising de novo in sleep were always correctly lateralizing. On the other hand, in patients who showed unilateral discharges in the awake state, whether ipsilateral or contralateral to the epileptogenic zone, the findings were generally unchanged during sleep.

Improvement of ischemic damage in gerbil hippocampal neurons by procaine

Acute cerebral ischemia induces membrane depolarization in the neuron, thereby incurring the simultaneous influx of various ions such as Na+ and Ca2+. Since procaine possesses the ability to inhibit the release of Ca2+ from intracellular Ca2+ stores to the cytosol as well as the ability to block Na+ channels, the effects of procaine on ischemia were investigated in the present study in gerbils both in vivo and in vitro. The histologic outcome was evaluated 7 days after 3 min of transient forebrain ischemia by assessing delayed neuronal death in hippocampal CA1 pyramidal cells in animals administered procaine (0.2, 0.4, or 2 micromol) intracerebroventricularly 10 min before ischemia and in animals given saline. The changes in the direct-current potential shift in the hippocampal CA1 area were measured using an identical animal model. A hypoxia-induced intracellular Ca2+ increase was evaluated by in vitro microfluorometry in gerbil hippocampal slices, and the effects of procaine (10, 50, and 100 micromol/l) on the Ca2+ accumulation were examined. Additionally, the effect of procaine (100 micromol/l) in a Ca2+-free condition was investigated. The histologic outcome was improved and the onset of the ischemia-induced membrane depolarization was prolonged by the preischemic administration of procaine. The increase in the intracellular concentration of Ca2+ induced by the in vitro hypoxia was suppressed by the perfusion of procaine-containing mediums (50 and 100 micromol/l), regarding both the initiation and the extent of the increase. A hypoxia-induced intracellular Ca2+ elevation in the Ca2+-free condition was observed, and the perfusion with procaine (100 micromol/l) inhibited this elevation. Procaine helps protect neurons from ischemia by suppressing the direct-current potential shift and by inhibiting the release of Ca2+ from the intracellular Ca2+ stores, as well as by inhibiting the influx of Ca2+ from the extracellular space.

Dexamethasone augments ischemia-induced extracellular accumulation of glutamate in gerbil hippocampus

Glucocorticoids exacerbate neuronal damage due to hypoxia, ischemia, seizure and hypoglycemia. Because the release of glutamate is closely involved in neuronal damage, the effects of dexamethasone on the ischemia-induced accumulation of extracellular amino acids (aspartate, glutamate, and glycine) were investigated in the gerbil hippocampal CA1 region by a microdialysis-high-performance liquid chromatography procedure in vivo. There were no differences in the extracellular concentrations of amino acids before ischemia between the control group and the dexamethasone (3m microg, i.c.v.)-injected group. The concentration of glutamate reached 246% of that before ischemia within 2.5 min of transient forebrain ischemia. Dexamethasone augmented the increase in glutamate to 508% of that before ischemia. This finding suggests that glucocorticoids aggravate ischemic neuronal damage by causing glutamate to accumulate in the extracellular space.

Changes in the brain monoamine metabolism in acute liver failure produced by ischemia-reperfusion injury in rats

OBJECTIVE

To investigate the relationship between behavioral alterations and changes in monoaminergic systems provoked by ischemia-reperfusion liver injury in rats.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

University animal laboratory.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

Acute liver failure was induced by occlusion of the left portal vein and the hepatic artery for 90 mins. Twenty animals were subjected to the behavioral examination. The brain water content was measured in 12 animals. Forty-two animals were used for the evaluation of brain monoamine turnover. Half of animals in each experiment were subjected to the ischemic operation.

MEASUREMENTS AND MAIN RESULTS

A step-through passive avoidance test was used for the behavioral evaluation 48 hrs after the ischemic operation. Then, plasma concentrations of amino acids were determined. The brain water content was measured with the dry weight method. The brain monoamine turnover was evaluated by the depletion of norepinephrine and dopamine induced by alpha-methyl-p-tyrosine, or the accumulation of 5-hydroxyindoleacetic acid induced by probenecid. In the plasma analysis performed 48 hrs after the operation, marked damage was found in animals subjected to liver ischemia. Injured rats demonstrated impairment in the passive avoidance test. The plasma concentrations of branch-chain amino acids were decreased, and the plasma concentrations of aromatic amino acids were increased. However, the brain water content was not changed by liver ischemia. The turnover of both norepinephrine in the cerebral cortex and dopamine in the striatum was decreased. The turnover of 5-hydroxytryptamine in the cerebral cortex was increased markedly.

CONCLUSION

In liver injury caused by liver ischemia, the excitatory neurotransmission by norepinephrine and dopamine is depressed and the inhibitory neurotransmission mediated by 5-hydroxytryptamine is facilitated, especially in the telencephalon.

[Effect of postmortem change on detection of apoptosis in rats]

Terminal deoxynucleotidyl transferase(TdT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay is useful to detect apoptotic cells in situ. We examined by hematoxylin-eosin (H-E) and TUNEL assay whether or not postmortem delay affects the development of apoptotic signals of cells in various organs. Wistar Imamichi rats were radiated by X-ray and sacrificed six hours after radiation. The spleen, thymus, adrenal and testis were excised and kept in a moist chamber at room temperature. Each tissue was fixed after different time intervals 0, 6, 12, 24 hours and paraffin-embedded sections were made. In the no-radiation group, a few of TUNEL positive cells were observed in the spleen, thymus and testis sections, but not in the adrenal. No increase in the number of apoptotic cells was observed with postmortem delay. In the radiation group, we observed in the spleen and thymus, much increase in the number of TUNEL positive cells, of which nuclei were clearly and deeply stained, corresponding to the area where shrinking nuclei were observed in H-E section. In testis sections, there was a little increase in the number of positively stained cells, and no change was observed in H-E section. With postmortem delay, the margin of the TUNEL positive cells changed from clear to indistinct, and the positive area was spread around. Our results show that it is difficult to distinguish apoptotic cells from postmortem change. It is possible, however, to detect TUNEL positive cell together with postmortem changes as the spread of the TUNEL positive area after 24 hours postmortem delay. It is important to consider the effect of the postmortem change when we adapt TUNEL assay to autopsy cases.

MR evaluation of human anterior cruciate ligament autograft on oblique axial imaging

PURPOSE

The purpose was to observe the changing MR appearance of stable anterior cruciate ligament (ACL) grafts on oblique axial images.

METHOD

Fifty-five knees in 44 patients were studied with MRI 1-54 months after arthroscopic ACL reconstruction with double-looped autogenous semitendinosus and gracilis tendons. Knees with poor stability were excluded from this study. Examinations were performed at 0.2 T with SE proton density and T2-weighted sagittal and oblique axial images.

RESULTS

High signal intensity areas covered the grafts 1-3 months after surgery. The high signal subsequently extended into the intertendinous bundles. The entire graft gradually became a low signal intensity bundle again after 12 months. Grafts were classified by their appearance on the oblique axial images.

CONCLUSION

We conclude that high signal intensity can be seen within stable ACL grafts.

Dexamethasone aggravates ischemia-induced neuronal damage by facilitating the onset of anoxic depolarization and the increase in the intracellular Ca2+ concentration in gerbil hippocampus

The Ca2+ mobilization across the neuronal membrane is regarded as a crucial factor in the development of neuronal damage in ischemia. Because glucocorticoids have been reported to aggravate ischemic neuronal injury, the effects of dexamethasone on ischemia-induced membrane depolarization, histologic outcome, and changes in the intracellular Ca2+ concentration in the gerbil hippocampus were examined in vivo and in vitro. The effects of metyrapone, an inhibitor of glucocorticoid synthesis, were also evaluated. Changes in the direct-current potential shift in the hippocampal CA1 area produced by transient forebrain ischemia for 2.5 minutes were compared among animals pretreated with dexamethasone (3 microg, intracerebroventricularly), metyrapone (100 mg/kg, intraperitoneally), and saline. The histologic outcome was evaluated 7 days after ischemia by assessing the delayed neuronal death in the hippocampal CA1 pyramidal cells of these animals. A hypoxia-induced intracellular Ca2+ increase was evaluated by in vitro microfluorometry in gerbil hippocampal slices, and the effect of dexamethasone (120 microg/L in the medium) on the cytosolic Ca2+ accumulation was examined. The effect in a Ca2+-free ischemialike condition was also investigated. Preischemic administration of dexamethasone reduced the onset latency of ischemia-induced membrane depolarization by 22%, and aggravated neuronal damage in vivo. In contrast, pretreatment with metyrapone improved the histologic outcome. The onset time of the increase in the intracellular concentration of Ca2+ provoked by in vitro hypoxia was advanced in dexamethasone-treated slices. The Ca2+-free in vitro hypoxia reduced the elevation compared with that in the Ca2+-containing condition. Treatment with dexamethasone facilitated the increase on both the initiation and the extent in the Ca2+-free condition. Aggravation of ischemic neuronal injury by endogenous or exogenous glucocorticoids is thus thought to be caused by the advanced onset times of both the ischemia-induced direct-current potential shift and the increase in the intracellular Ca2+ concentration.

[Placement of self-expanding metallic stents in the stenotic trachea and bronchus under the support of gas exchange by extracorporeal lung assist (ECLA)]

Three self-expanding metallic stents (MS) were placed in a patient with severe dyspnea due to tracheo-bronchial stenosis caused by a large metastatic malignant tumor. To ensure adequate gas exchange, we used ECLA during surgery. After ECLA was started with V-V bypass (blood flow 1.3 l.min-1, 100% O2 flow 10 l.min-1), the patient was administered droperidol and fentanyl, and orotracheally intubated with an endotracheal tube (7.0 mm ID) using a bronchofiberscope. Anesthesia was maintained with midazolam, but no neuromuscular blocking agent was used. The pulmonary ventilation was withheld 3 times during each period of 5-10 min for MS placement through the endotracheal tube. The patient was ventilated for a few min between each procedure. Values of arterial blood gas were maintained within physiological ranges throughout the surgery. ECLA was a useful means of ensuring adequate gas exchange in perioperative patients with difficult airway.

Stretch-activated channels in arterial smooth muscle of genetic hypertensive rats

Electrical and contractile responses of small arteries to mechanical stress are reportedly enhanced in spontaneously hypertensive rats (SHR), compared with those in Wistar Kyoto rats (WKY). We have previously shown that stretch-activated cation channels exist in arterial smooth muscle membrane, of which opening causes Na+ and Ca2+ influx and membrane depolarization. We thus hypothesize that activation of stretch-activated channels is enhanced in arterial smooth muscle of SHR compared with WKY. To test this hypothesis, stretch-activated currents were recorded in single smooth muscle cells of resistance mesenteric arteries from SHR and WKY (16 to 24 weeks of age). In the whole-cell recording, membrane stretch was applied by inflating the cell with positive pressure to the recording pipette. Cell-inflation evoked Gd3+-sensitive cation currents. This current appeared with less stretch stimulation and its amplitude was larger in SHR cells compared with WKY cells. In the cell-attached recording, suction to the recording pipette evoked single stretch-activated channel currents (conductance of 32 pS with 150 mmol/L Na+), which were blocked by Gd3+. Channels were activated with less negative pressure and their availability was greater in SHR cells than in WKY cells. Results suggest that the activation of stretch-activated channels is enhanced in smooth muscle of resistance arteries from SHR compared with WKY, which may contribute to the enhanced vascular responses to mechanical stress in SHR.

Lidocaine suppresses the anoxic depolarization and reduces the increase in the intracellular Ca2+ concentration in gerbil hippocampal neurons

BACKGROUND

The movement of ions, particularly Ca2+, across the plasma membrane of neurons is regarded as an initial element of the development of ischemic neuronal damage. Because the mechanism by which lidocaine protects neurons against ischemia is unclear, the effects of lidocaine on the ischemia-induced membrane depolarization, histologic outcome, and the change in the intracellular Ca2+ concentration in the gerbil hippocampus were studied.

METHODS

The changes in the direct-current potential shift in the hippocampal CA1 area produced by transient forebrain ischemia for 4 min were compared in animals given lidocaine (0.8 micromol administered intracerebroventricularly) 10 min before ischemia and those given saline. The histologic outcome was evaluated 7 days after ischemia by assessing delayed neuronal death in hippocampal CA1 pyramidal cells in these animals. In a second study, hypoxia-induced intracellular Ca2+ increases were evaluated by in vitro microfluorometry in gerbil hippocampal slices, and the effects of lidocaine (10, 50, and 100 microM) on the Ca2+ accumulation were examined. In addition, the effect of lidocaine (100 microM) drug perfusion with a Ca2+-free ischemia-like medium was investigated.

RESULTS

The preischemic administration of lidocaine delayed the onset of the ischemia-induced membrane depolarization (anoxic depolarization) and reduced its maximal amplitude. The histologic outcome was improved by the preischemic treatment with lidocaine. The in vitro hypoxia-induced increase in the intracellular concentration of Ca2+ was suppressed by the perfusion with lidocaine-containing mediums (50 and 100 microM), regarding the initiation and the extent of the increase. The hypoxia-induced intracellular Ca2+ elevation in the Ca2+-free condition was similar to that in the Ca2+-containing condition. Perfusion with lidocaine (100 microM) inhibited this elevation in the Ca2+-free condition.

CONCLUSIONS

Lidocaine helps protect neurons from ischemia by suppressing the direct-current potential shift, by inhibiting the release of Ca2+ from the intracellular Ca2+ stores, and by inhibiting the influx from the extracellular space.

Interleukin-1 modulates protein tyrosine phosphatase activity and permeability of brain endothelial cells

Interleukin-1 alpha (IL-1 alpha) and interleukin-6 (IL-6), both known to be able to open the blood-brain barrier (BBB), downregulated plasma membrane-associated tyrosine phosphatase activity in primary porcine brain endothelial cells (PBEC). In contrast, transforming growth factor beta (TGF-beta) upregulated PTP activity and tumor necrosis factor alpha (TNF-alpha) had no effect. Plasma membrane-associated PTP activity of PBEC was upregulated at contact inhibited growth arrest. Tightly confluent cells reduced 3H-inulin permeability by 34% compared with just confluent cells indicating the formation of barrier properties. The decrease in permeability temporally correlated with the elevated PTP activity of the cells at growth arrest and was reversed to control by IL-1 alpha. Vanadate, a broad-specificity PTP inhibitor, also enhanced 3H-inulin permeability. These data suggest that IL-1 alpha-induced endothelial permeability could be controlled through lowering PTP activity.

Cellular distribution of mammalian DNA topoisomerase II is determined by its catalytically dispensable C-terminal domain

Mammalian cells express two genetically distinct isoforms of DNA topoisomerase II, designated topoisomerase IIalphaand topoisomerase IIbeta. We have recently shown that mouse topoisomerase IIalpha can substitute for the yeast topoisomerase II enzyme and complement yeast top2 mutations. This functional complementation allowed functional analysis of the C-terminal domain (CTD) of mammalian topoisomerase II, where the amino acid sequences are divergent and species-specific, in contrast to the highly conserved N-terminal and central domains. Several C-terminal deletion mutants of mouse topoisomerase IIalpha were constructed and expressed in yeast top2 cells. We found that the CTD of topoisomerase IIalphais dispensable for enzymatic activity in vitro but is required for nuclear localization in vivo. Interestingly, the CTD of topoisomerase IIbetawas also able to function as a signal for nuclear targeting. We therefore examined whether the CTD alone is sufficient for nuclear localization in vivo . The C-terminal region was fused to GFP (green fluorescent protein) and expressed under the GAL1 promoter in yeast cells. As expected, GFP signal was exclusively detected in the nucleus, irrespective of the CTD derived from either topoisomerase IIalphaor IIbeta. Surprisingly, when the upstream sequence of each CTD was added nuclear localization of the GFP signal was found to be cell cycle dependent: topoisomerase IIalpha-GFP was seen in the mitotic nucleus but was absent from the interphase nucleus, while topoisomerase IIbeta-GFP was detected predominantly in the interphase nucleus and less in the mitotic nucleus. Our results suggest that the catalytically dispensable CTD of topoisomerase II is sufficient as a signal for nuclear localization and that yeast cells can distinguish between the two isoforms of mammalian topoisomerase II, localizing each protein properly.

The effect of dopamine depletion on the H2O2 production in the rat striatum following transient middle cerebral artery occlusion

The changes in the extracellular concentrations of rat striatal H2O2, dopamine (DA) and its metabolites during middle cerebral artery (MCA) occlusion and reperfusion were simultaneously examined by microdialysis, and the relationship between the ischemia-induced release of DA and the generation of H2O2 was estimated by assessing the effect of the lesion of the substantia nigra (SN). In the rats without SN lesions, a significant increase in the striatal H2O2 level was observed during the ischemia and reperfusion phases. In the rats with SN lesions, the ischemia-induced H2O2 production was not attenuated. These results suggest that DA is not an important source of H2O2 in cerebral ischemia and reperfusion.

Effects of CP-060S on membrane channels in vascular smooth muscle cells from guinea pig

The newly developed cardioprotective drug, CP-060S, (-)-(S)-2-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-3-[3-[N-methyl-N- [2-(3,4-methylenedioxyphenoxy) ethyl] amino] propyl]-1,3-thiazolidin-4-one hydrogen fumarate, is reported to possess a vasodilating action. Our objective was to examine the effects of CP-060S on the membrane channels in mesenteric arterial cells from guinea pigs, using whole-cell patch-clamp techniques. CP-060S inhibited the Ca2+ channel current in a concentration-dependent manner (ED50 = 1.7 microM at a holding potential of -80 mV and a stimulation frequency of 0.1 Hz). The inhibition was potentiated by a more depolarized holding potential and a higher stimulation frequency. These effects of CP-060S resembled those of diltiazem and gallopamil more than to those of nifedipine; the inhibition was more frequency dependent and less holding-potential dependent than with nifedipine. Higher concentrations of CP-060S also inhibited the delayed K+ channel currents (ED50 = 18 microM). The present observations suggest that CP-060S exhibits the profile of a Ca2+ channel antagonist, similar to that of diltiazem and gallopamil.

Age-related changes of serum progastrin-releasing peptide levels during childhood

Gastrin-releasing peptide (GRP) has attracted much attention in recent years because it has become recognized as a significant tissue-specific growth factor. To investigate the physiological significance of this peptide in growing children, the time course of serum ProGRP(31-98) level, a precursor hormone of GRP, in children was assessed. A total of 118 serum samples including cord blood was examined with informed consent by using a specific enzyme-linked immunosorbent assay (ELISA) system to measure serum ProGRP(31-98). The serum ProGRP(31-98) level was highest in cord blood and neonatal samples, rapidly declined by 1 year of age and then gradually declined to the adult level by 5 years of age. This time-dependent change of serum ProGRP(31-98) level suggests the importance of GRP as a physiological growth factor in fetal and neonatal tissues.

Depressed natural killer cell activity due to decreased natural killer cell population in a vitamin E-deficient patient with Shwachman syndrome: reversible natural killer cell abnormality by alpha-tocopherol supplementation

Natural Killer (NK) cell activity was examined in a 16-month-old Japanese boy with Shwachman syndrome associated with severe vitamin E deficiency. As evaluated by 51Cr-release assay from K562 cells, NK cell activity was constantly decreased. After 8 weeks of oral alpha-tocopherol (alpha-Toc) supplementation (100 mg/day), NK cell activity had normalised. When alpha-Toc supplementation was interrupted for 16 weeks. NK cell activity again decreased. Flow cytometry of peripheral lymphocytes revealed a lowered number of CD16+ CD 56- fraction, which has the most potent NK cell activity. Single cell-in-agarose assay, to investigate the binding and cytolytic activity of NK cell at the single cell level, revealed that the number of NK cells which bind to K562 cell was decreased, but that the cytolytic activity of the individual binding cell was relatively unaffected. A second supplementation of alpha-Toc for 8 weeks successfully restored NK cell activity, the number of cells expressing NK cell markers and the number of K562-binding cells as compared to the age-matched normal range.

CONCLUSION

These results indicate that severe vitamin E deficiency caused impaired NK cell activity due to a decrease in the number of CD16+ CD56- NK cells and that this abnormality is reversible with alpha-Toc supplementation.

Knowledge and attitudes of Japanese dental health care workers towards HIV-related disease

OBJECTIVE

The present study was undertaken to investigate knowledge of AIDS and HIV infection among Japanese dental health care workers, the source of that knowledge and attitudes of dental workers towards infected patients.

METHODS

The study population surveyed by means of a self-administered questionnaire consisted of 174 dental health workers at Nagasaki University Dental Hospital, including students and trainee hygienists.

RESULTS

Most respondents (100% response) claimed their major source of AIDS knowledge to be derived from the media. Almost all considered their knowledge of AIDS and HIV infection to be more than moderate but still inadequate. The majority of respondents would be hesitant about performing dental treatment on HIV-positive patients. It was widely anticipated that dental patients infected with HIV would increase in the next few years and many were anxious about the increasing occupational risk of HIV infection. Only 22.4% of respondents had the same attitude towards treating HIV-positive and HIV-negative patients. Most also considered that they would be able to take care of the oral opportunistic diseases associated with HIV. Over 90.0% of respondents requested additional education about HIV, particularly information about the prevention and spread of the virus and cross-infection requirements.

CONCLUSION

It is concluded that further training in the medical and psychological aspects of treating HIV-positive patients is indicated in Japan.

ABO genotyping by PCR-direct sequencing

The PCR-direct sequence method was applied to ABO genotyping. At the 261st nucleotide of the genes of A and B glycosyltrasferase, it was easily detected that the nucleotide was guanine in AA, AB and BB genotypes and that the nucleotide was ademine in only OO. In AO and BO, substitution of A to G was confirmed by the dye primer method, but it was difficult to detect correctly by the dye terminator method. At the 297th, nucleotide substitution between A and B alleles was confirmed by the both methods. As this position, O allele was subdivided into three types, OAOA, OGOG and OAOG. At the 703rd, nucleotide substitution between A and B alleles was easily detected by the both methods. The PCR-direct sequence method was suitable to confirm the nucleotide substitution or deletion directly and to prevent the mistyping by other methods.

[Application of stochastical analysis to maternity testing without putative mother]

In a maternity test in which the putative mother was deceased, the cumulative probability of maternity (PM) was calculated at 0.822 from 24 genetic markers by the stochastical method. This PM may not be evaluated in the same way as that of usual paternity cases. We applied the same method to two families whose blood relationships were undoubted. We compared the PMs in the cases in which maternal genotypes were estimated and were defined. Also, we calculated the PMs in the case of real maternal relationship and false maternal one. The estimated PM from real maternity relationship was significantly higher than that from false maternal one.