Exercise-induced ST-segment depression and systolic dysfunction in patients with nonobstructive hypertrophic cardiomyopathy

BACKGROUND

ST-segment depression is common in patients with hypertrophic cardiomyopathy (HCM). However, it is not clear whether exercise-induced ST-segment depression in patients with HCM and patent coronary arteries is associated with changes in left ventricular function.

METHODS

Left ventricular function was continuously evaluated in 53 patients with nonobstructive HCM during supine ergometer exercise with a radionuclide ventricular function monitor equipped with a cadmium telluride detector. On the basis of the ST-segment changes during exercise, the patients were divided into 2 groups: group N had no ST-segment depression, and group D had >/=0.1 mV ST-segment depression.

RESULTS

Exercise duration, blood pressure, heart rate, and rate-pressure product during exercise did not differ between the 2 groups. End-diastolic volume at rest and at peak exercise did not differ between groups D and N. In contrast, the end-systolic volume in group N decreased during exercise, whereas in group D it increased. As a result, the left ventricular ejection fraction in group D decreased from 70% +/- 7% to 59% +/- 15% (P <.0001), whereas ejection fraction in group N increased from 65% +/- 8% to 71% +/- 11% (P =.0002). There was a strong correlation between exercise-induced ST-segment depression and changes in ejection fraction from rest to peak exercise (P <.0001).

CONCLUSIONS

These results suggest that the exercise-induced ST-segment depression seen in patients with nonobstructive HCM is associated with systolic dysfunction during exercise.

Extended neuronal protection induced after sublethal ischemia adjacent to the area with delayed neuronal death

In the present study, we investigated whether neurons adjacent to an ischemic lesion acquire tolerance against subsequent ischemia or not. We initially used unilateral hemispheric ischemia for 3 min in gerbils to produce an ischemic lesion confined to the unilateral CA1 sector, and the presence of tolerance was examined in the adjacent CA3 sector through transient global ischemia by occlusion of both common carotid arteries. Attenuation of neuronal damage was clearly observed in neurons in the CA3 sector adjacent to the ischemic lesion in the CA1 sector. The phenomenon lasted for up to two weeks after the initial hemispheric ischemia, but was no longer present two months later. Reactive astrocytes as identified by the presence of glial fibrillary acidic protein were visible in the CA3 hippocampus four days and two weeks after hemispheric ischemia, but they were scarce two months later. Expression of heat shock protein 72 in the CA3 neurons was observed four days after hemispheric ischemia, but the reaction returned to the control level two weeks later. In conclusion, the present study showed that tolerance in the neurons adjacent to an ischemic lesion could be sustained at least for two weeks, and raised the possibility that reactive astrocytes might contribute to the extended tolerance in neurons.

ASC1/RAS2 suppresses the growth defect on glycerol caused by the atp1-2 mutation in the yeast Saccharomyces cerevisiae

To better define the regulatory role of the F(1)-ATPase alpha-subunit in the catalytic cycle of the ATP synthase complex, we isolated suppressors of mutations occurring in ATP1, the gene for the alpha-subunit in Saccharomyces cerevisiae. First, two atp1 mutations (atp1-1 and atp1-2) were characterized that prevent the growth of yeast on non-fermentable carbon sources. Both mutants contained full-length F(1)alpha-subunit proteins in mitochondria, but in lower amounts than that in the parental strain. Both mutants exhibited barely measurable F(1)-ATPase activity. The primary mutations in atp1-1 and atp1-2 were identified as Thr(383) --> Ile and Gly(291) --> Asp, respectively. From recent structural data, position 383 lies within the catalytic site. Position 291 is located near the region affecting subunit-subunit interaction with the F(1)beta-subunit. An unlinked suppressor gene, ASC1 (alpha-subunit complementing) of the atp1-2 mutation (Gly(291) --> Asp) restored the growth defect phenotype on glycerol, but did not suppress either atp1-1 or the deletion mutant Deltaatp1. Sequence analysis revealed that ASC1 was allelic with RAS2, a G-protein growth regulator. The introduction of ASC1/RAS2 into the atp1-2 mutant increased the F(1)-ATPase enzyme activity in this mutant when the transformant was grown on glycerol. The possible mechanisms of ASC1/RAS2 suppression of atp1-2 are discussed; we suggest that RAS2 is part of the regulatory circuit involved in the control of F(1)-ATPase subunit levels in mitochondria.

Characterization of the selective staining of DNA on gels using two fluorochromes

Ethidium bromide (EB) and 4'-6-diamidino-2-phenylindole (DAPI) are both well-known fluorochromes for detecting DNA fragments. EB binds to DNA by intercalation and DAPI binds in the DNA minor groove. We previously developed a staining method using both EB and DAPI that is selective for AT-rich DNA fragments. Using this double-staining method, AT-rich DNA fragments are visualized as bluish-white fluorescent bands. To further characterize this method, a series of synthetic DNA fragments were designed with systematic variations in the length, AT content, and DNA sequence pattern. The staining properties of these fragments were determined in the presence of DAPI and EB, and the following results were obtained. (i) In a series of fragments with three AT base pairs followed by one GC base pair, the stained DNA fragments exhibited different fluorescent colors and varied from bluish (more DAPI staining) to pinkish (less DAPI staining) in the order 5'-AAA-3', 5'-AAT-3', 5'-ATA-3', 5'-TTA-3'. (ii) In fragments with constant AT content, the blue fluorescent color increased with increasing number of A (or T) nucleotides, due to increased DAPI binding. The blue color was saturated when the number of A (or T) nucleotides was 12 or greater. (iii) The fluorescent color of the stained DNA fragments changed in the order of red-orange, pink, pinkish-white, white, bluish-white, blue as the AT content increased from 0 to 100%. Thus, the fluorescent color of DNA fragments stained with DAPI and EB depends on base composition and nucleotide sequence, suggesting that individual stained DNA fragments may have characteristic and specific fluorescent colors. The fluorescent color emitted by specific stained DNA fragments in the presence of EB and DAPI can be analyzed with a high degree of sensitivity and resolution using the XYZ colorimetric system.

Deficiency of intercellular adhesion molecule 1 fails to mitigate selective neuronal death after transient global ischemia

Recent studies have shown a crucial role of intercellular adhesion molecule 1 (ICAM-1) in expansion of infarction after focal cerebral ischemia. The purpose of the present study was to assess whether ICAM-1 is involved in selective neuronal vulnerability and reactive gliosis after transient forebrain ischemia. ICAM-1 knockout mice and wild-type mice were subjected to transient forebrain ischemia for 5, 10 or 15 min, and the hippocampus and caudoputamen were examined 7 days later with conventional histological and immunohistochemical methods. Bilateral common carotid artery occlusion with less than 10% of baseline cortical microperfusion for 10 or 15 min resulted in ischemic neuronal damage in the hippocampus and caudoputamen. The frequency and the severity of neuronal damage were similar in wild-type and knockout mice. Proliferation of reactive astrocytes in the hippocampus was also similar in both types of mice. Therefore, it is highly unlikely that ICAM-1 plays a key role in delayed neuronal death after transient global ischemia or in astroglial responses after ischemic neuronal injury.

Hepatocellular carcinoma with spontaneous regression of multiple lung metastases

Spontaneously regressed lung metastasis of hepatocellular carcinoma (HCC) in a 82-year-old Japanese man with liver cirrhosis was recorded. Multiple nodular lesions of both lungs, up to 1 cm across, were shown on chest X-ray when the clinical diagnosis of HCC was made because of the presence of a liver mass on abdominal computed tomography (CT) scan and high serum alpha-fetoprotein (AFP) value. The lung lesions which were regarded clinically as metastasis of HCC decreased in number and size 7 months later, and subsequently disappeared a further 7 months radiographically. However, the liver mass revealed no reduction on abdominal CT, despite normalization of the serum AFP value, and the patient died 7 months after the disappearance of the lung lesions. The patient refused biopsy for the liver mass and anticancerous treatment during the course of the disease. At autopsy, the liver mass, 13 cm in diameter, histologically featured moderately differentiated HCC. Only one metastasis, 0.5 cm across, was obvious in the left lower lung lobe. In addition, there were 14 minute lesions in both lungs, up to 0.2 cm across, including three with complete necrosis and 11 with histocytic reaction and fibrosis. The necrotic tissue was filled with large ghostly cells that appeared to be debris from a neoplastic tissue, regardless of no viable tumor cells among them. The clinical and autopsy findings highly suggested that the patient developed spontaneous regression of multiple lung metastases of HCC and subsequently left the very small lesions as the vestige. Thus, the histology of these lesions may exhibit a process of the regression as the sequence of events, i.e., a transition from necrosis of the metastatic HCC to its fibrosis. Presence of an effective factor(s) in relation to the regression was unclarified. There has been no reported cases with regression of the only metastasis of HCC in the literature to date.

DNA cleavage and proteolysis of microtubule-associated protein 2 after cerebral ischemia of different severity

We report temporal profiles of cytoplasmic proteolysis and genomic DNA cleavage after cerebral ischemia of different severity in gerbils. Global forebrain ischemia by bilateral common carotid artery occlusion for 5 min with reperfusion, severe unilateral hemispheric ischemia by unilateral common carotid artery occlusion for 30 min with reperfusion, and complete ischemia by decapitation were used. The hippocampus was examined for proteolysis by using immunohistochemistry for microtubule-associated protein 2, DNA cleavage by using in situ nick-end labelling, and nuclear morphology by Hematoxylin staining. During evolution of delayed neuronal death after transient forebrain ischemia, loss of the immunoreaction for microtubule-associated protein 2 occurred almost in parallel with DNA cleavage in the CA1 region. In contrast, disappearance of the immunoreaction for microtubule-associated protein 2 was much faster than genomic DNA cleavage after unilateral hemispheric ischemia and reperfusion. The microtubule-associated protein 2 immunoreactivity was completely lost before development of changes in nuclear morphology or DNA cleavage after complete ischemia. The present study demonstrated the differences between necrosis and delayed neuronal death, but the nuclear morphology in the latter was not exactly the same as seen in apoptosis. Some elements of both necrotic and apoptotic machineries may work following transient ischemia, and the degree of ischemic insult may determine the character of cell death process.

Plasma endothelin-1 elevation associated with alcohol-induced variant angina

Vasospastic angina as a result of alcohol ingestion has been reported, but the mechanism of alcohol-induced coronary artery spasm is presently unknown. This report presents 2 cases of alcohol-induced variant angina (VA) with elevated levels of plasma endothelin-1 after alcohol ingestion. In case 1, the plasma endothelin-1 concentration was 3.15 pg/ml before drinking (normal <2.30 pg/ml) and increased to 4.09 pg/ml when measured 5 h after alcohol ingestion. After 2 months of abstinence, the plasma endothelin-1 concentration was 2.88 pg/ml and 6 months after abstinence, it decreased to 2.03 pg/ml (normal range). In case 2, the plasma endothelin-1 concentration was 2.44 pg/ml before drinking and increased to 4.36 pg/ml when measured 5 h after alcohol ingestion. After 2 months of abstinence, the plasma endothelin-1 concentration was 3.04 pg/ml and 6 months after abstinence, it decreased to 2.09 pg/ml (normal range). These 2 cases suggest that a relationship may exist between alcohol-induced VA and elevation in the plasma endothelin-1 concentration after alcohol ingestion.

The three copies of the ATP1 gene are arranged in tandem on chromosome II of Saccharomyces cerevisiae S288C

In the yeast Saccharomyces cerevisiae there are three copies of the F(1)F(0)-ATPase alpha-subunit gene ATP1 on chromosome II (Takeda et al., 1995). However, after genome analysis using S. cerevisiae strain S288C, only one ATP1 gene sequence was observed (Feldman et al., 1994; Obermaier et al., 1995). To check whether the number of copies of ATP1 is strain-dependent or not, we carried out three different experiments: (a) long-PCR analyses of total DNAs isolated from several reference strains, carried out by preparing 29-mer oligonucleotides based on the 5'- and 3'- up- and downstream regions of the ATP1 nucleotide sequence using the data from the genome project to synthesize primers; (b) restriction analyses of chromosome II from the reference strains with SplI; and (c) long-PCR analyses of prime clones 70113 and 70804, both of which contained two ATP1 gene copies, ATP1a and ATP1b, and ATP1b and ATP1c, respectively, using 30 nucleotides just inside the 3'-end (sense) and 5'-end (antisense) of the ATP1-coding region as primers. In the case of the long-PCR experiments, the reference strains DC5, SEY2102, W303-1A, W303-1B, LL20 and DBY746, as well as strain S288C, generated a DNA fragment of approximately 32 kb, which hybridized with ATP1. During SplI digestion, a DNA fragment of more than 50 kb which hybridized with ATP1, was obtained from all reference strains. In the case of prime clone analyses using the long-PCR experiments, the distance between ATP1a and ATP1b or ATP1b and ATP1c was approximately 10 kb or 7 kb, respectively. The S288C strain generated these two DNA fragments, as do the other strains. These results showed that all these strains contained three copies of ATP1 on chromosome II.

Molecular cloning of a novel member of the HSP110 family of genes, ischemia-responsive protein 94 kDa (irp94), expressed in rat brain after transient forebrain ischemia

To identify genes induced by transient forebrain ischemia, we used the mRNA differential display technique in the four-vessel occlusion model in rats. Some genes were identified as candidates that encode ischemia-responsive protein, and one of them was cloned as ischemia-responsive protein 94 kDa (irp94) from the rat hippocampal cDNA library. Sequence analysis suggested that rat irp94 was a transcriptional variant or a homologue of mouse apg-2 and human heat shock protein (hsp) 70RY and a member of the HSP110 family, because IRP94 was >90% identical to APG-2 and HSP70RY and approximately 60% identical to the other members of the HSP110 family. Although irp94 mRNA was constitutively expressed in the normal hippocampus, it was clearly enhanced 4-24 h after ischemia for 10 (1.9-fold increase) and 15 min (3.4-fold increase). These changes mainly occurred in neuronal cells, as judged by the localization of irp94 mRNA using in situ hybridization histochemistry. On the other hand, hyperthermic stress did not enhance irp94 mRNA expression, suggesting that irp94 expression was enhanced under ischemic stress and not related to the heat shock signaling mechanism. Our study suggested that irp94, a novel member of the HSP110 family, might play an important role in the environment altering neuronal functions, especially after transient forebrain ischemia.

Species differences in fodrin proteolysis in the ischemic brain

There has been growing evidence that the breakdown of cytoskeletal proteins is an important biochemical change leading to ischemic neuronal death. In the present study, we investigated species differences in the susceptibility of fodrin to calpain activation induced by cerebral ischemia in gerbils, rats, and mice. In vivo fodrin proteolysis and degradation of microtubule-associated protein 2 after complete ischemia occurred more rapidly in the hippocampus and cerebral cortex of the gerbil brain than in the corresponding area of the rat and mouse brain. The N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 injected intraperitoneally before ischemia did not diminish fodrin degradation in the gerbil hippocampus. In vivo fodrin proteolysis was inhibited at 33 degrees C and enhanced at 41 degrees C compared with proteolysis at 37 degrees C during ischemia. However, in vitro fodrin proteolysis after addition of Ca2+ into the crude membrane fraction did not show any differences among three species. Although it is highly unlikely that the difference in the sensitivity of NMDA receptor or the sensitivity of calpain activation to calcium was the crucial determinant of susceptibility of fodrin degradation in the gerbil brain, the present study clearly demonstrated that fodrin in the gerbil brain was more susceptible to calpain activation induced by ischemia than that in the rat and mouse brains. Enhanced proteolysis may be one of the reasons neurons in the gerbil brain are highly vulnerable to ischemia.

Deficiency of intercellular adhesion molecule 1 attenuates microcirculatory disturbance and infarction size in focal cerebral ischemia

Recent evidence has shown crucial roles for cell-adhesion molecules in inflammation-induced rolling, adhesion, and accumulation of neutrophils in tissue. Intercellular adhesion molecule-1 (ICAM-1) is one of these adhesion molecules. Previous studies have shown marked reduction in the size of infarction after focal cerebral ischemia by depletion of granulocytes and administration of the antibody against ICAM-1. In the present study we investigated the role of ICAM-1 in the size of ischemic lesions, accumulation of granulocytes, and microcirculatory compromise in focal cerebral ischemia by using ICAM-1-knockout mice. Ischemic lesions were significantly mitigated in knockout mice after permanent and transient focal ischemia, even though the number of granulocytes in the infarcted tissue was almost the same between knockout and wild-type mice. Depletion of granulocytes further decreased the size of ischemic lesions after transient focal ischemia in ICAM-1-knockout mice. Microcirculation was reduced after focal ischemia, but it was better preserved in the cerebral cortex of knockout mice than that of wild-type mice. The present study demonstrated that ICAM-1 played a role in microcirculatory failure and subsequent development and expansion of infarction after focal cerebral ischemia. However, it is highly unlikely that ICAM-1 played a key role in accumulation of granulocytes after focal cerebral ischemia.

[Chronic pancreatitis, acute pancreatitis]

MRCP has been recognized as a safe and noninvasive diagnostic method. In the present study we evaluated the usefulness of MRCP in diagnosis of chronic and acute pancreatitis. Two-dimensional fast asymmetric spin-echo (FASE) MRCP was performed in 40 patients with chronic pancreatitis and 13 with acute pancreatitis. In 29 patients (72.5%) with chronic pancreatitis and 9 (66.7%) with acute pancreatitis, main pancreatic duct (MPD) was visualized entirely. MRCP could demonstrate the characteristic findings of chronic pancreatitis such as dilatation and irregularity of MPD in most cases. In acute pancreatitis, MRCP indicated that MPD was normal in diameter, but irregular in configuration compared with that of the control group. MRCP may facilitate the diagnosis of chronic and acute pancreatitis.

Cerebral ischemia after bilateral carotid artery occlusion and intraluminal suture occlusion in mice: evaluation of the patency of the posterior communicating artery

Cerebral ischemia models using mice have drawn increasing attention, particularly because of the availability of transgenic animals. However, the variability of intracranial vasculature at the circle of Willis in mice can influence the degree of ischemia in both the bilateral common carotid artery (CCA) occlusion and intraluminal suture occlusion models. We have developed a method to predict the extent of the anastomosis between carotid and vertebrobasilar circulation in three mouse strains (C57BL/6, CBA, and DBA/2) by measuring cortical microperfusion with laser Doppler flowmetry during a 1-minute occlusion of both CCA. When animals showed residual cortical microperfusion of less than 12% during bilateral CCA occlusion, the mice showed absence of functional anastomosis, developed ATP depletion in the frontal cortex during occlusion, and had ischemic neuronal death in the hippocampus and caudoputamen after occlusion for 15 minutes and recirculation for 7 days. Furthermore, those mice exhibited decreased local cerebral blood flow and associated ischemic neuronal death in the hippocampus, within the territory supplied by the posterior cerebral artery, with the intraluminal suture occlusion model. The current study demonstrates the need for assessment of intracranial vasculature in each animal by measuring cortical microperfusion during temporary occlusion of both CCA, no matter whether cerebral ischemia is produced by bilateral CCA occlusion or intraluminal suture occlusion in transgenic mice.

Ischemic tolerance in hippocampal CA1 neurons studied using contralateral controls

We induced ischemic tolerance unilaterally in gerbil hippocampus using the contralateral hippocampus as control. Ischemia for 2 min of right common carotid occlusion was reversible but sufficient to cause heat-shock protein 70 production in CA1 neurons. This pretreatment given four days prior to occlusion of both common carotids for 5 min, but not at longer preceding intervals, induced tolerance in right CA1 neurons. Neuroprotection was still evident two months after the 5 min occlusion. Adenosine triphosphate content and immunoreactive microtubule associate protein 2 in the hippocampus showed that the 5 min ischemic insult was essentially equal in both hemispheres. Repetitive pretreatments at two day intervals caused almost complete protection of CA1 neurons against subsequent 5 min ischemia, while a single pretreatment showed 80% protection. However, the increase in heat-shock protein 70 with repeated pretreatments was not significantly more than with one pretreatment. We concluded that true ischemic tolerance was induced by ischemic stress itself, was long-lasting, was not due to mitigation of subsequent ischemia, and was augmented by repetition without further increase of heat-shock protein 70.

Ischemic damage and subsequent proliferation of oligodendrocytes in focal cerebral ischemia

In order to achieve a better understanding of the pathophysiology of ischemic white matter lesions, oligodendrocytic degeneration and subsequent proliferation were examined in the mouse model of middle cerebral artery occlusion. In situ hybridization histochemistry for proteolipid protein messenger RNA was employed as a sensitive and specific marker of oligodendrocytes, and immunohistochemistry for myelin basic protein was used as a compact myelin marker. Immunohistochemistry for microtubule-associated protein 2 and albumin was employed to monitor neuronal degeneration and the breakdown of the blood brain barrier, respectively. In the ischemic core of the caudoputamen, the immunoreactivity for microtubule-associated protein 2 disappeared and massive albumin extravasation occurred several hours after vessel occlusion, while proteolipid protein messenger RNA signals remained relatively strong at this time. The messenger RNA signals began to attenuate 12 h after ischemia and were hardly detectable 24 h after ischemia in the whole ischemic lesion. In situ end-labeling of fragmented DNA showed some cells with proteolipid protein messenger RNAs to have DNA fragmentation at this period. In contrast to proteolipid protein messenger RNA signals, the immunoreactivity for myelin basic protein was detected as long as five days after ischemia. An apparent increase in the cells possessing strong proteolipid protein messenger RNA signals was found five days after ischemia, mainly in the corpus callosum and the cortex bordering the infarcted areas. A double simultaneous procedure with in situ hybridization for proteolipid protein messenger RNA and immunohistochemistry for glial fibrillary acid protein or lectin histochemistry for macrophages/microglia showed proliferating oligodendrocytes to be co-localized with reactive astrocytes and macrophages/microglia. These findings show that oligodendrocytic damage occurred following ischemic neuronal damage and the breakdown of the blood brain barrier, but preceded the breakdown of myelin proteins in the ischemic lesion, that an apoptosis-like process was involved in ischemic oligodendrocytic death, and that surviving oligodendrocytes responded and proliferated in the outer border of the infarcted area.

Analysis of amyloid deposition in a transgenic mouse model of homozygous familial amyloidotic polyneuropathy

Amyloid fibrils derived from the Japanese, Portuguese, and Swedish types of familial amyloidotic polyneuropathy all consist of a variant transthyretin (TTR) with a substitution of methionine for valine at position 30 (TTR Met 30). In an attempt to establish an animal model of TTR Met-30-associated homozygous familial amyloidotic polyneuropathy and to study the structural and functional properties of human TTR Met 30, we generated a mouse line carrying a null mutation at the endogenous ttr locus (ttr-/-) and the human mutant ttr gene (6.0-hMet 30) as a transgene. In these mice, human TTR Met-30-derived amyloid deposits were first observed in the esophagus and stomach when the mice were 11 months of age. With advancing age, amyloid deposits extended to various other tissues. Because no significant difference was detected in the onset, progression, and tissue distribution of amyloid deposition between the ttr-/- and ttr+/+ transgenic mice expressing 6.0-hMet 30, endogenous normal mouse TTR probably does not affect the deposition of human TTR Met-30-derived amyloid in mice. TTR is a tetramer composed of four identical subunits that binds thyroxine (T4) and plasma retinol-binding protein. The introduction of 6.0-hMet 30 into the ttr-/- mice significantly increased their depressed serum levels of T4 and retinol-binding protein, suggesting that human TTR Met 30 binds T4 and retinol-binding protein in vivo. The T4-binding ability of human TTR Met 30 was confirmed by the analysis of T4-binding proteins in the sera of ttr-/- transgenic mice expressing 6.0-hMet 30. The T4-binding studies also demonstrated the presence of hybrid tetramers between mouse and human TTR subunits in the ttr+/+ transgenic mice expressing 6.0-hMet 30.

C57BL/6 strain is most susceptible to cerebral ischemia following bilateral common carotid occlusion among seven mouse strains: selective neuronal death in the murine transient forebrain ischemia

Rats and gerbils have been used widely to investigate the molecular mechanism of selective neuronal death following transient global ischemia. Recently, the availability of transgenic mice has enabled us to examine the involvement of specific gene products in various pathophysiological conditions. However, there has been only limited information about the experimental model of cerebral ischemia in mice, particularly in regard to selective neuronal death. We examined whether bilateral carotid occlusion produced global forebrain ischemia in seven common mouse strains including C57BL/6, ICR, BALB/c, C3H, CBA, ddY and DBA/2, based on neurological signs, histological findings and cortical microcirculatory as well as India ink perfusion patterns. The C57BL/6 strain was found to be the most susceptible among seven strains. All C57BL/6 mice died within 6 h after permanent bilateral carotid occlusion. After transient bilateral carotid occlusion for 20 min, more than 90% of C57BL/6 mice showed typical neurological signs such as torsion of the neck and rolling fits, and developed selective neuronal death in the hippocampus and caudoputamen. Hypothermia prevented the neuronal death. Visualization of brain vasculature by India ink perfusion indicated that the susceptibility of the mice after bilateral carotid occlusion depended mainly on the degree of anastomosis between carotid and basilar arteries. Our results showed the feasibility of investigating selective neuronal death in transgenic mice with simple temporary occlusion of both common carotid arteries, when those from the C57BL/6 strain or inbred transgenic mice from other strains with the C57BL/6 strain in a back-cross manner are used.

Mucinous cystadenoma with malignant transformation arising in the renal pelvis

Mucinous cystadenoma with malignant transformation occupying the lower half portion of the right renal pelvis in a 69-year-old Japanese man was recorded. The patient had recent dysuria but no clinical history of pyelonephritis or urolithiasis. Under the clinical diagnosis of unusual renal cyst, the right total nephrectomy was performed. Grossly, the cystic tumor, 5 cm across, formed a monolocular lumen filled with mucins and showed no direct communication with the renal pelvis inside. Microscopically, the epithelial lining was characterized by a single layer of benign mucin producing columnar cells that scattered foci of non-invasive papillary projections with cell stratification and nuclear atypia suggestive of malignancy. Although there was non-specific chronic pyelitis, no pyelitis cystica et glandularis was encountered. Of circa 60 glandular neoplasms arising in the renal pelvis reported previously, adenomas are only five including two mucinous cystadenomas, while the remainder are adenocarcinomas. The histological findings of mucinous cystadenoma in the present case may represent the process of a transition from adenoma to adenocarcinoma. The result suggests the possibility that adenoma-carcinoma sequence may exist among the glandular neoplasma arising in the renal pelvis. The histogenesis was unclarified.

Effect of systemic zinc administration on delayed neuronal death in the gerbil hippocampus

The divalent cation zinc has been reported to possess several physiological properties such as blocking apoptotic cell death through an inhibitory effect on Ca(2+)-Mg2+ endonuclease activity, or modulating the neurotoxicity via glutamate receptor subtypes. In the present study, we investigated the effect of peripherally injected zinc on delayed neuronal death seen in the hippocampus after transient global ischemia, in order to elucidate a possible beneficial role on zinc in ischemic neuronal cell death. Forty-five adult Mongolian gerbils of both sexes underwent transient bilateral clipping of the common carotid arteries for 3 min. In the pretreated animals, ZnCl2 (20 mg/kg) was injected subcutaneously once, 1 h before ischemia (superacute group; n = 6) or twice at 24 and 48 h before ischemia (subacute group; n = 14). Histological survey was carried out 3 days later by in situ DNA fragmentation method and 4 days later by hematoxylin-eosin staining by semiquantatively counting dead neurons in the CA1 sector. Subacute zinc pre-administration significantly reduced the nuclear damage and subsequent neuronal death; however, superacutely pre-administered zinc did not protect hippocampal neurons against ischemia but it did not aggravate the effect of ischemia, either. The present study suggested that transfer of exogenous zinc into the intracellular space is required for neuroprotection, presumably via the anti-endonuclease activity.

Induction of cyclooxygenase-2 mRNA in gerbil hippocampal neurons after transient forebrain ischemia

We examined the effect of brain ischemia on neuronal expression of cyclooxygenase-2 gene in the hippocampus. Transient forebrain ischemia was produced by occluding bilateral carotid arteries for 5 min in Mongolian gerbil. Northern blotting and in situ hybridization demonstrated that expression of cyclooxygenase-2 mRNA was transiently induced in the hippocampal neurons. Although future studies will be needed to clarify if induced cyclooxygenase-2 following ischemia is involved in neuronal damage or neuronal protection, selective cyclooxygenase-2 inhibitors may be a new therapeutical approach for the treatment of stroke.

Effect of immunosuppressant FK506 on ischemia-induced degeneration of hippocampal neurons in gerbils

To evaluate the effect of FK506 on delayed neuronal death in gerbils after forebrain ischemia, 84 adult Mongolian gerbils were used in this study. Transient forebrain ischemia was induced by clipping common carotid arteries bilaterally for 5 minutes. One hour after reperfusion we intraperitoneally injected FK506 (1.0 mg/kg), cyclosporin A (CsA) (10.0 mg/kg) or the vehicle solution into each gerbil. In one group, each agent was additionally administered daily 3 more times at 24, 48 and 72 hours after ischemia. The gerbils were killed 4 days or 10 days after transient ischemia, and damage to their hippocampal pyramidal cells was histologically assessed. Additionally, the body temperature was measured following administration of each drug to investigate drug-induced hypothermia. Post-ischemic repeated treatment with FK506 significantly (p < 0.01) reduced degeneration of hippocampal neurons. However, partial treatment did not modify neuronal degeneration. CsA did not show a neuroprotective effect in this study. Drug-induced mild hypothermia (35-37 C) was observed following administration of FK506 or CsA. There was no significant difference in the time course of the body temperature between the FK506 and CsA group. We demonstrated that the repeated FK506 treatment, but not the CsA treatment, reduced ischemia-induced degeneration of hippocampal neurons in gerbils. Although FK506-induced hypothermia might have modified neuronal degeneration, a comparison with CsA indicated that the neuroprotective effect of FK506 was not solely due to hypothermia per se.

Delayed neuronal death in ischemic hippocampus involves stimulation of protein tyrosine phosphorylation

Glutamate triggers neuronal degeneration after ischemia-reperfusion in the brain. However, the details of intracellular signal transduction that propagates cell death remain unknown. The present work investigated whether protein tyrosine phosphorylation mediates neuronal death in the ischemic brain. Transient forebrain ischemia for 5-10 min in Mongolian gerbils or intoxication with the glutamate analogue kainic acid (12 mg/kg) in Sprague-Dawley rats caused neuronal death selectively in the hippocampus 2-4 days or 1 day later, respectively. Under these conditions, 160-, 115-, 105-, 92-, and 85-kDa proteins showed a significant increase in tyrosyl residue phosphorylation selectively in the hippocampus 3-12 h after ischemia or 4-8 h after kainic acid-induced seizures. Tyrosine kinases, including pp60c-src, were activated without a change of tyrosine phosphatases. Administration of radicicol, a selective inhibitor of tyrosine kinases, attenuated stimulation of tyrosine phosphorylation and hippocampal degeneration after ischemia or kainic acid injection. The results suggest that protein tyrosine phosphorylation might propagate delayed neuronal death in the mature hippocampus through glutamate overload after ischemia-reperfusion.

Bifemelane hydrochloride enhances 'ischemic tolerance' phenomenon in gerbil hippocampal CA1 neurons

Neurons are so vulnerable to ischemic insults that transient forebrain ischemia for 5 min killed most CA1 neurons in the gerbil hippocampus (surviving neurons: 4%). In contrast, 2 days after a nonlethal challenge of 2-min ischemia, 51% of CA1 neurons became resistant to subsequent, otherwise lethal ischemia for 5 min. Bifemelane hydrochloride (20 mg/kg, i.p.), which helps ischemic brain recover from oxidative stress and inhibition of protein synthesis, significantly enhanced the 'ischemic tolerance' phenomenon if injected 1 day after 2-min ischemia: 94% of neurons survived after 5-min ischemia. This finding carries implications for possible preventive treatment following warning signs of transient ischemic attack.