Role of the ryanodine receptor in ischemic brain damage--localized reduction of ryanodine receptor binding during ischemia in hippocampus CA1

1. The ryanodine receptor has recently been shown to play a pivotal role in the regulation of intracellular Ca2+ concentration via Ca(2+)-induced Ca2+ release (CICR). Effects of ischemia on CICR in the brain tissue, however, remain largely unknown since only a few reports have been published on this subject. In this paper we report on work in this area by our group and review related progress in this field. 2. We examined alterations of ryanodine receptor binding and local cerebral blood flow (LCBF) at 15 min, 30 min, and 2 hr after occlusion of the right common carotid artery in the gerbil brain. A quantitative autoradiographic method permitted simultaneous measurement of these parameters in the same brain. The LCBF was significantly reduced in most of the cerebral regions on the occluded side during each time period of ischemia. In contrast, only in the hippocampus CA1 on the occluded side was a significant reduction in ryanodine binding found at 15 min, 30 min and 2 hr after the occlusion. 3. These findings suggest that suppression of ryanodine binding in the hippocampus CA1 may be attributable to a regionally specific perturbation of CICR and that this perturbation may be closely associated with the pathophysiological mechanism that leads to be selective ischemic vulnerability of this region. 4. Other recent studies have also reported an important role for ryanodine receptors in neuronal injury such as the delayed neuronal death in the hippocampus CA1. These data suggest that derangement of CICR is likely to be involved in acute neuronal necrosis as well as in delayed neuronal death in ischemia. 5. Further studies on clarifying the role of CICR in ischemic brain damage are needed in order to develop new therapeutic strategies for stroke patients.

Role of cortical microtubules in the orientation of cellulose microfibril deposition in higher-plant cells

Cortical microtubules (MTs) have been implicated in the morphogenesis of plant cells by regulating the orientation of newly deposited cellulose microfibrils (CMFs). However, the role of MTs in oriented CMF deposition is still unclear. We have investigated the mechanism of CMF deposition with cultured tobacco protoplasts derived from taxol-treated BY-2 cells (taxol protoplasts). The BY-2 protoplasts regenerated patches of beta-l,3-glucan (callose) and fibrils of beta-l,4-glucan (cellulose). Taxol protoplasts possessed the same ordered MT arrays as material cells and regenerated CMFs with patterns almost coincidental with MTs. Electron microscopy revealed that, on the surface of cultured taxol protoplasts, each CMF bundle appeared to be deposited on each cortical MT. These results suggest that MTs may attach directly to the cellulose-synthesizing complexes, by some form of linkage, and regulate the movement of these complexes in higher-plant cells.

[A case of giant advanced breast cancer responding remarkably to chemo-endocrine therapy chiefly with doxifluridine]

A 68-year-old woman presented with advanced ulcerative breast cancer of the precordium; edema of the face, cervix and bilateral upper extremities; dyspnea from carcinomatous pleurisy; and multiple bone metastases, which suggested a terminal state. Her general condition improved with symptomatic therapies; thus, doxifluridine (5'-DFUR) and an endocrine therapeutic drug were given to reduce the primary focus, eliminate the edemas and decrease the plural effusion. When the tumor markers increased again, CEFT therapy [cyclophosphamide (CPA), epirubicin (epi-ADM), 5-fluorouracil (5-FU) and tamoxifen (TAM)] was conducted. This resulted in no adverse drug reaction, further reduction of the primary focus, and extremely improved Performance status (PS). The patient was discharged on 5'-DFUR and TAM therapy, which resulted in scarring of the ulcer, normalization of tumor marker levels, disappearance of the pleural effusion, and a reduction of metastatic bone foci. The findings suggest 5'-DFUR and endocrine therapeutic drugs can have a favorable clinical effect without impacting QOL and should be employed in patients with advanced cancer and poor general condition.

[Central nervous system tuberculosis: diagnosis and therapy]

Tuberculous meningitis is the most serious form of tuberculosis, but often the only manifestation of tuberculosis with non-specific initial signs and symptoms. Therefore, delayed diagnosis occasionally results into rapid progression of neurologic deficits and a poor prognosis. So, it is needless to mention that appropriate chemotherapy should be started as fast as possible under swift diagnosis. According to recent progression of molecular biological technique, PCR and other nucleic acid amplification methods are becoming to be quite useful for rapid detection of Mycobacterium tuberculosis in the cerebrospinal fluid. If diagnostic tests are not definitely positive but there is a strong clinical suspicion for tuberculous meningitis, it is advisable to start the antituberculous chemotherapy as soon as possible. The combination chemotherapy with isoniazid, rifampicin, pyrazinamide, and streptomycin (or ethambutol) is a standard treatment for tuberculous meningitis. The administration of corticosteroids with adequate antituberculous chemotherapy should be considered in severe cases for reduction in mortality and neurologic sequelae, especially when there is the indication of subarachnoid block or impending brain herniation.

Successful surgical treatment for hepatic encephalopathy caused by a pancreatic siphon: report of a case

We report herein the case of a 39-year-old man with cirrhosis of the liver who developed hepatic encephalopathy and progressive diabetes caused by a pancreatic siphon after undergoing a distal splenorenal shunt (DSRS) for a variceal hemorrhage. Radiologic occlusion was judged to be inappropriate because of the extensive DSRS. The DSRS was surgically closed 6 years after the operation to restore portal perfusion. To alleviate the portal hypertension, splenectomy and gastric devascularization were performed, which proved successful, as the encephalopathy disappeared completely, the ammonia levels decreased, liver function improved, and the diabetes subsided. Our experience indicates that a small percentage of cirrhotic patients who undergo DSRS with longterm followup may develop various undesirable complications, although some of these patients benefit from a combination of surgical shunt occlusion, splenectomy, and gastric devascularization.

Phylogenetic position of the Phacotaceae within the Chlamydophyceaeas revealed by analysis of 18S rDNA and rbcL sequences

Four genera of the Phacotaceae (Phacotus, Pteromonas, Wislouchiella, Dysmorphococcus), a family of loricated green algal flagellates within the Volvocales, were investigated by means of transmission electron microscopy and analysis of the nuclear encoded small-subunit ribosomal RNA (18S rRNA) genes and the plastid-encoded rbcL genes. Additionally, the 18S rDNA of Haematococcus pluvialis and the rbcL sequences of Chlorogonium elongatum, C. euchlorum, Dunaliella parva, Chloromonas serbinowii, Chlamydomonas radiata, and C. tetragama were determined. Analysis of ultrastructural data justified the separation of the Phacotaceae into two groups. Phacotus, Pteromonas, and Wislouchiella generally shared the following characters: egg-shaped protoplasts, a single pyrenoid with planar thylakoid double-lamellae, three-layered lorica, flagellar channels as part of the central lorica layer, mitochondria located in the central cytoplasm, lorica development that occurs in mucilaginous zoosporangia that are to be lysed, and no acid-resistant cell walls. Dysmorphococcus was clearly different in each of the characters mentioned. Direct comparison of sequences of Phacotus lenticularis, Pteromonas sp., Pteromonas protracta, and Wislouchiella planctonica revealed DNA sequence homologies of >/=98. 0% within the 18S gene and 93.9% within the rbcL gene. D. globosus was quite different from these species, with a maximum of 92.9% homology in the 18S rRNA and </=86.6% in the rbcL gene. It showed major similarities to the 18S rDNA of Dunaliella salina, with 95.3%, and to the rbcL sequence of Chlamydomonas tetragama, with 90.3% sequence homology. Additionally, the Phacotaceae sensu stricto exclusively shared 10 (rbcL: 4) characters which were present neither in other Chlamydomonadales nor in Dysmorphococcus globosus. Different phylogenetic analysis methods confirmed the hypothesis that the Phacotaceae are polyphyletic. The Phacotaceae sensu stricto form a stable cluster with affinities to the Dunaliellaes and possibly Haematococcus pluvialis. Dysmorphococcus globosus represented an independent lineage that is possibly related to Chlamydomonas moewusii and C. tetragama.

[Serum albumin level and activities of daily living in centenarians]

The relationship between serum albumin level and activities of daily living was studied in 95 centenarians. There were 73 women (12 rank J: free-living, 18 rank A: unable to go outside without help, 20 rank B: bedridden but able to sit on the bed, 23 rank C: completely bedridden) and 22 men (9 rank J, 7 rank A, 6 rank B or C). The serum albumin level (mean +/- S.D. 4.0 +/- 0.4 g/dl) of the rank J women was at the lower limit of normal for young adults. The albumin levels of rank A, rank B, and rank C were 3.7 +/- 0.4 g/dl, 3.5 +/- 0.3 g/dl, and 3.4 +/- 0.4 g/dl, respectively. The levels of rank B and rank C women were significantly lower than that of rank J women. The albumin level of rank J men (3.9 +/- 0.3 g/dl) was lower than that of young adults. The albumin level of ranks B and C men (3.1 +/- 0.3 g/dl) was significantly lower than that of rank J men. The A/G ratio or albumin fraction (%) measured by serum electrophoresis was similar to that of the serum albumin level of centenarians of both sexes. There were no significant differences in the serum protein level or in the peripheral hemoglobin level between rank J centenarians and those of other ranks, for both sexes. The serum albumin level is a valuable indicator of the ability to perform activities of daily living and may be a useful prognostic index in centenarians.

[Serum globulin levels and activities of daily living in centenarians]

Serum globulin levels in 101 centenarians (77 women, 24 men) were analyzed by zonal electrophoresis and immunoglobulin assays. Six subjects showed an M band in electrophoretograms. Five M bands were immunoglobulin G (IgG) type and one was IgA. One subject was suspected to suffer from IgG-type multiple myeloma, and the others were thought to have essential (benign) monoclonal gammopathy. The relationship between serum globulin levels and activities of daily living (ADL) was studied in remaining 95 subjects. There were 21 rank-J (free-living), 25 rank-A (unable to go outside without help), 23 rank-B (bedridden but able to sit on the bed), and 26 rank-C (completely bedridden) centenarians. The mean serum alpha 1-, alpha 2-, and beta-globulin level in the rank-J centenarians was at the upper limit of the normal adult range. The mean alpha 1-globulin levels in rank-B (3.3 +/- 0.4%) and C (3.4 +/- 0.5%) subjects were significantly higher than those in rank-J (2.9 +/- 0.3%) centenarians. The mean serum gamma-globulin level of rank-J centenarians (16.9 +/- 3.7%) was within the normal range. The mean gamma-globulin levels in rank-B (21.0 +/- 2.7%) and C (22.8 +/- 4.9%) subjects were significantly higher than that in rank-J centenarians. The mean immunoglobulin G concentrations in rank-B (1.620 +/- 304 mg/dl) and C (1.720 +/- 392 mg/dl) subjects were significantly higher than those in rank-J centenarians (1.320 +/- 361 mg/dl) and in normal adults (1.150 +/- 235 mg/dl). IgA concentrations in all centenarians were higher than in normal controls. There was no significant difference in IgA or IgM concentration between rank-J subjects and those in other ranks. Serum globulin levels measured with electrophoresis, and the immunoglobulin concentrations, can be valuable indicators of the ability to perform activities of daily living, and may be useful predictors of subclinical diseases or morbidity in centenarians.

Biotransformation of shiromodiol diacetate, myli-4(15)-en-9-one and myliol by Aspergillus niger

Microbiol biotransformation of shiromodiol diacetate from Neolitsea serisea koids, and of myli-4(15)-en-9-one and myliol from the liverwort Mylia taylorii, were carried out with Aspergillus niger IFO 4407. A. niger hydroxylated the allyl position (C-2) of shiromodiol diacetate, and one of the geminal dimethyl groups of myli-4(15)-en-9-one and myliol regioselectively. The structures of these transformants were elucidated by spectral analysis and confirmed by X-ray analysis.

Anthraquinones from Neonauclea calycina and their inhibitory activity against DNA topoisomerase II

In a series of searches for DNA topoisomerase II inhibitors from naturally occurring compounds, a wood extract of Neonauclea calycina MERR. (Rubiaceae) showed a moderate effect in vitro. Purification of the extract resulted in the isolation of seven known anthraquinones. The structures were characterized as damnacanthal, rubiadin 1-methyl ether, nordamnacanthal, morindone, damnacanthol, lucidin 3-O-primeveroside and morindone 6-O-primeveroside by spectral analysis, respectively. Damnacanthal and morindone showed an intensive inhibitory effect against topoisomerase II (IC50: 20 micrograms/ml and 21 micrograms/ml).

Characterization of rbcL group IA introns from two colonial volvocalean species (Chlorophyceae)

Group I introns were reported for the first time in the large subunit of Rubisco (rbcL) genes, using two colonial green algae, Pleodorina californica and Gonium multicoccum (Volvocales). The rbcL gene of P. californica contained an intron (PIC intron) of 1320 bp harboring an open reading frame (ORF). The G. multicoccum rbcL gene had two ORF-lacking introns of 549 (GM1 intron) and 295 (GM2 intron) base pairs. Based on the conserved nucleotide sequences of the secondary structure, the PIC and GM1 introns were assigned to group IA2 whereas the GM2 intron belonged to group IA1. Southern hybridization analyses of nuclear and chloroplast DNAs indicated that such intron-containing rbcL genes are located in the chloroplast genome. Sequencing RNAs from the two algae revealed that these introns are spliced out during mRNA maturation. In addition, the PIC and GM1 introns were inserted in the same position of the rbcL exons, and phylogenetic analysis of group IA introns indicated a close phylogenetic relationship between the PIC and GM1 introns within the lineage of bacteriophage group IA2 introns. However, P. californica and G. multicoccum occupy distinct clades in the phylogenetic trees of the colonial Volvocales, and the majority of other colonial volvocalean species do not have such introns in the rbcL genes. Therefore, these introns might have been recently inserted in the rbcL genes independently by horizontal transmission by viruses or bacteriophage.

Presence of the CO2-concentrating mechanism in some species of the pyrenoid-less free-living algal genus Chloromonas (Volvocales, Chlorophyta)

Physiological and morphological characteristics related to the CO2-concentrating mechanism (CCM) were examined in several species of the free-living, unicellular volvocalean genus Chloromonas (Chlorophyta), which differs morphologically from the genus Chlamydomonas only by lacking pyrenoids. The absence of pyrenoids in the chloroplasts of Chloromonas (Cr.) rosae UTEX 1337, Cr. serbinowii UTEX 492, Cr. clatharata UTEX 1970, Cr. rosae SAG 26.90, and Cr. palmelloides SAG 32.86 was confirmed by light and electron microscopy. In addition, immunogold electron microscopy demonstrated that ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) molecules were distributed almost evently throughout the chloroplasts in all five Chloromonas strains. However, Chloromonas exhibited two types of physiological characteristics related to the CCM depending on the species or strains examined. Chloromonas rosae UTEX 1337 and Cr. serbinowii had high photosynthetic affinities for CO2 in cells grown in culture medium bubbled with air (low-CO2 cells), compared with those grown in medium bubbled with 5% CO2 (high-CO2 cells), indicating the presence of the low-CO2-inducible CCM. In addition, these two Chloromonas strains exhibited low-CO2-inducible carbonic anhydrase (CA; EC 4.2.1.1) activity and seemed to have small intracellular inorganic carbon pools. Therefore, it appears that Cr. rosae UTEX 1337 and Cr. serbinowii possess the CCM as in pyrenoid-containing microalgae such as Chlamydomonas reinhardtii. By contrast, Cr. clatharata, Cr. rosae SAG 26.90 and Cr. palmelloides showed low photosynthetic affinities for CO2 when grown under both CO2 conditions. Moreover, these three strains exhibited an apparent absence of intracellular inorganic carbon pools and lacked low-CO2-inducible CA activity. Thus, Cr. clatharata, Cr. rosae SAG 26.90 and Cr. palmelloides, like other pyrenoid-less algae (lichen photobionts) reported previously, seem to lack the CCM. The present study is the first demonstration of the CCM in pyrenoid-less algae, indicating that pyrenoids or accumulation of Rubisco in the chloroplasts are not always essential for the CCM in algae. Focusing on this type of CCM in pyrenoid-less algae, the physiological and evolutionary significance of pyrenoid absence is discussed.

Binding capacity of FK506 binding protein after 2-hour hemispheric ischemia in gerbil brain

The binding capacity of FK506 binding protein (FKBP) was examined after 2-h hemispheric ischemia in the gerbil brain in order to clarify the precise mechanism of the neuroprotective effects of FK506. Firstly, the FK506 binding was evaluated in vitro in the normal gerbil brain using 1 nM [3H]dihydro-FK506 as a specific ligand. FK506 binding sites were distributed in a rather homogeneous manner, although the greatest binding was noted in the hippocampus CA1. Secondly, Scatchard analysis demonstrated that the binding sites of FK506 could be composed of two components in each brain region. Thirdly, 18 Mongolian gerbils were divided into two groups: an ischemia group (n = 12) and a sham group (n = 6). The right common carotid artery was ligated to induce hemispheric ischemia for 2 h in the ischemia group. The local cerebral blood flow was measured at the end of the experiment by the [14C]iodoantipyrine method. The ligated animals with levels of local cerebral blood flow in the lateral nuclei of the thalamus of less than 50 ml/100 g/min were utilized as the ischemia group (n=6) for further data analysis. No significant differences in FK506 binding between the ischemia and sham groups were observed in any regions. The above data indicate that the binding capacity of FKBP tends to remain normal during 2-h ischemia, suggesting that FK506 may exert its neuroprotective effects through its binding to FKBP in the brain during the early phase of cerebral ischemia.

Analysis of the cluster of ribosomal protein genes in the plastid genome of a unicellular red alga Cyanidioschyzon merolae: translocation of the str cluster as an early event in the rhodophyte-chromophyte lineage of plastid evolution

The nucleotide sequence of a cluster of ribosomal protein genes in the plastid genome of a unicellular red alga, Cyanidioschyzon merolae, which has been supposed to be the most primitive alga, was determined. The phylogenetic tree inferred from the amino acid sequence of ribosomal proteins of two rhodophytes, a chromophyte, a glaucophyte, two chlorophytes (land plants), a cyanobacterium, and three eubacteria suggested a close relationship between the cyanobacterium Synechocystis PCC6803 and the plastids of various species in the kingdom Plantae, which is consistent with the hypothesis of the endosymbiotic origin of plastids. In this tree, the two species of rhodophytes were grouped with the chromophyte, and the glaucophyte was grouped with the chlorophytes. Analysis of the organization of the genes encoding the ribosomal proteins suggested that the translocation of the str cluster occurred early in the lineage of rhodophytes and chromophytes after these groups had been separated from chlorophytes and glaucophytes.

Numerical and functional characteristics of lymphocyte subsets in centenarians

The immune system in the aged is a very interesting subject for study. In this study, analysis was extended to extrathymic T cells as well as NK cells and "conventional" T cells (i.e., thymus-derived T cells) in terms of their constitution and function in both healthy and unhealthy centenarians. Middle-aged persons were used as controls. Healthy and unhealthy centenarians showed lower levels in the proportion and absolute number of lymphocytes. The major change in the constitution of lymphocyte subsets was increased levels in the proportion of NK cells (CD56+/CD57+) and extrathymic T cells (CD3+CD57+). Inversely, conventional T cells decreased in proportion and function (i.e., proliferative response to mitogen). Although NK cells increased in centenarians, NK activity by whole lymphocytes and the purified NK fraction decreased. The difference between healthy and unhealthy centenarians was small in all parameters, the only difference being a lower level of expression of CD56 antigens on CD57+ T cells in unhealthy centenarians. These results indicate that there is a major shift in lymphocyte population from conventional T cells to NK cells and extrathymic T cells with aging. Concerning the age-associated increases in CD56+ T and CD57+ T cells, these cells correspond to NK1+ T cells in mice.

Collection of anopheline mosquitos in three villages endemic for malaria in Khammouane, Lao PDR

Anopheline mosquito collections were made during the months of May and June (dry season) and August (rainy season), 1996 at villages, Nakham, Namdik and Hinboon Neua in Khammouane Province. Larval collections were also made in 3 slow running streams around Nakham villages in May 1996. Altogether, 3,549 adult females consisting 19 Anopheles species were collected by 3 nights of human and 6 animal bait traps and 3 resting collections. Among them, Anopheles vagus (19.75%), An. philippinensis (15.02%), An. nivipes (11.55%), An. pallidus (11.27%), An. peditaeniatus (8.34%), An. kochi (8.00%) and An. barbirostris (7.27%) were predominant species. The immatures of An. barbirostris, An. minimus, An. maculatus sensu lato, and An. culicifacies were found in the streams of Nakham. It is noteworthy that An. minimus, An. dirus and An. maculatus sensu lato, which are well known malaria vectors in Thailand, were recorded for the first time in this area.

Relationship between pupil size and acetylcholinesterase activity in patients exposed to sarin vapor

OBJECTIVE

To elucidate the effect of sarin vapor on pupil size and erythrocyte acetylcholinesterase activity (AchE).

DESIGN

Retrospective observational survey.

SETTING

Emergency department of an urban teaching hospital.

PATIENTS

80 patients who were exposed to sarin in a terrorist attack in Tokyo subways.

MEASUREMENTS AND RESULTS

Pupil size and AchE activity on the day of exposure were measured. Among the 80 patients, the pupils were miotic (< 3 mm) in 50 patients (62.5%), while AchE activity was below the normal range (< 1.2 U) in 34 patients (42.5%). AchE was significantly lower in the miotic group than in the group with normal pupils (1.0 +/- 0.5 U vs 1.5 +/- 0.3 U, p < 0.01). In the miotic group, AchE activity was lower than normal in 32 patients (64.0%) but was decreased in only 2 patients in the normal pupil group (6.7%) (p < 0.01).

CONCLUSIONS

Miosis is a more sensitive index of exposure to sarin vapor than erythrocyte AchE. Systemic poisoning is apparently less likely to develop if the patient's pupil size is normal on arrival at the hospital.

Acute ischemic vulnerability of PKA in the dendritic subfields of the hippocampus CA1

Alterations of [3H]cyclic AMP (cAMP) binding, an indicator of the binding activity of particulate cyclic AMP-dependent protein kinase (PKA), were examined after 15 and 30 min of ischemia in the gerbil brain. Severe hemispheric cerebral ischemia was induced by occluding the right common carotid artery. Significant reductions in cAMP binding were noted only in the dendritic subfields of the hippocampus CA1 such as the strata oriens, radiatum and lacunosum-moleculare, on the ischemic side after 15 min of ischemia. After 30 min ischemia cAMP binding was significantly decreased not only in each dendritic subfield of the hippocampus CA1, but also in the layer of pyramidal cell bodies (stratum pyramidale) on the occluded side; other brain regions such as the hippocampus CA3, dentate gyrus and cerebral cortices revealed no significant changes in cAMP binding. These findings suggest that derangement of PKA may begin in the dendritic subfields of the hippocampus CA1 after as little as 15 min of severe ischemia, and proceed centrally to the neuronal cell bodies of the hippocampus CA1.

Tissue and subcellular distributions, and characterization of rat brain protein phosphatase 2A containing a 72-kDa delta/B" subunit

A 74-kDa delta/B" subunit was isolated by heparin-Sepharose column chromatography from human erythrocyte protein phosphatase 2A (PP2A) consisting of a 34-kDa catalytic subunit (alpha/C) and 63- and 74-kDa regulatory subunits (beta/A and delta/B") in a ratio of 1:1:1. The purified delta/B" was used as an immunogen in mice, to prepare specific antisera against delta/B". Immunoblot analyses with the antisera detected an immunoreactive 72-kDa protein in the cytosol from various rat tissues including erythrocytes, brain, lung, testis, adrenal gland, heart, spleen, kidney, and liver. The 72-kDa protein was highly abundant in brain and was distributed evenly in cerebral cortex, cerebellum, and brain stem. The 72-kDa protein was also detected in mitochondria and microsome fractions. An immunoreactive 68-kDa protein was detected mainly in nuclear and microsome fractions. The 72-kDa protein from rat brain cytosol copurified with phosphorylated H2B histone phosphatase activity during successive chromatographies on DEAE-Toyopearl, AH-Sepharose, Sephadex G-150, H1 histone-Toyopearl, TSK DEAE-5PW, protamine-Toyopearl, and TSK G3000SW columns. The purified enzyme migrated as a single protein band on nondenaturing PAGE and as three protein bands of 34, 63, and 72 kDa in a ratio of 1:1:1 on SDS-PAGE. The molecular weight of the enzyme was estimated to be 170,000 from the s20,W value of 7.2 +/- 0.3 S and the Stokes radius of 5.5 +/- 0.1 nm. The rat brain enzyme was classified as PP2A, based on the following properties; (1) an IC50 for okadaic acid of 10(-9) M; (2) its preferential dephosphorylation of the a subunit of phosphorylase kinase; (3) its insensitivity to protein inhibitor 2; and (4) its heterotrimeric subunit structure. The Km value and the molecular activity of the enzyme for phosphorylated H2B histone were 72.3 +/- 0.3 microM and 192 +/- 2 mol Pi released/min/mol enzyme, respectively, and were comparable to those of human erythrocyte PP2A (alpha1 beta1 delta1/ CAB"). The 72-kDa subunit in the purified rat brain PP2A was phosphorylated in vitro by cAMP-dependent protein kinase.

Rapid reduction in ryanodine binding of hippocampus CA1 in cerebral ischemia

Ryanodine receptors located on the sarcoplasmic or endoplasmic reticulum, play an important role in the regulation of the intracellular Ca2+ level via the mechanism of Ca(2+)-induced Ca2+ release (CICR). Perturbation of intracellular Ca2+ regulation has been considered to be one of the most important mechanisms underlying acute ischemic neuronal damage. The ryanodine binding, an indicator of intracellular channels of CICR, and local cerebral blood flow (LCBF) were therefore examined at 15 min post-ischemia in the gerbil brain. The autoradiographic method developed in our laboratory enabled us to determine both parameters within the same brain. Severe hemispheric cerebral ischemia was induced by occluding the right common carotid artery. LCBF was measured at the end of the experiment using [14C]iodoantipyrine method. The ryanodine binding was evaluated autoradiographically in vitro using [3H] ryanodine. A group of gerbils who underwent a sham procedure served as controls. LCBF was found to be significantly decreased in most cerebral regions on the occluded side. In contrast, a significant reduction in ryanodine binding was noted only in the hippocampus CA1 on the occluded side. Taken together, these findings indicate that the CICR in the hippocampus CA1 may be especially susceptible to acute ischemic stress, and be closely associated with the pathophysiological mechanisms of the selective vulnerability of this region.

Calcineurin inhibitor, FK506, prevents reduction in the binding capacity of cyclic AMP-dependent protein kinase in ischemic gerbil brain

We examined the effects of FK506, a specific inhibitor of calcineurin, on the binding capacity of cyclic AMP-dependent protein kinase (cAMP-DPK) in gerbils subjected to 2-h cerebral hemispheric ischemia. FK506 (0.1 mg/kg) was infused intravenously at 15 min prior to the induction of ischemia by common carotid artery occlusion. The binding capacity of cAMP-DPK was evaluated by autoradiographic analysis of the cAMP binding, and cerebral blood flow (CBF) was measured by the [14C] iodoantipyrine method. In the sham-operated gerbils. FK506 significantly increased mean arterial blood pressure and tended to decrease CBF, suggesting that FK506 may constrict systemic blood vessels as well as cerebral blood vessels. On the other hand, cAMP binding was not altered by FK506 in the sham-operated gerbils. In the ischemia group of gerbils, FK506 prevented any significant reduction of cAMP binding in the hippocampus CA1 and cerebral cortices on the ischemic side, whereas it exerted no significant influence on the cAMP binding of the nonischemic side. The values of CBF were comparable between the vehicle-treated gerbils and FK506-treated gerbils in the ischemic regions. Preservation of cAMP binding indicates that intracellular signal transduction via cAMP-DPK can be maintained by FK506 despite ischemia, suggesting that this agent may be beneficial for reducing ischemic tissue damage.

[Clinical features of 5 cases of tuberculous meningitis--with special reference to brain CT and MRI findings]

We evaluated the clinical features of 5 cases of tuberculous meningitis who had been admitted to our department from 1987 to 1994. Three patients were male and two were female. Their age ranged from 17 to 74 years old. All cases were examined by both CT and MRI before and during antituberculous treatment. Before the treatment, CT scan revealed abnormal findings such as nodular lesion suggesting tuberculoma, subarachnoid contrast enhancement or cerebral infarction in 2 cases, while MRI revealed abnormal findings such as inflammatory lesions with Gd-enhancement in 4 out of 5 patients. During the treatment, all abnormal findings except cerebral infarction disappeared. No abnormal findings were detected by CT. MRI and SPECT in one case who showed right hemiparesis and motor aphasia. In summary, CT scan could demonstrate abnormal findings in only a small portion of patients with tuberculous meningitis. One the other hand, MRI revealed various abnormal findings in most patients, and could reveal some lesions which could be responsible for the symptoms of patients. In a few patients, however, MRI could not show any lesion in spite of obvious focal neurological signs. MRI is considered to be useful for detecting the lesions in most patients with tuberculous meningitis, although its findings are not always specific for the disease.

Respiratory stimulation and generation of superoxide radicals in Pseudomonas aeruginosa by fungal naphthoquinones

The mechanism of action of antimicrobial naphthoquinones from the fungus Fusarium was studied by using Pseudomonas aeruginosa. Bostricoidin, methyl ether fusarubin, and fusarubin stimulated the oxygen consumption of bacterial cells and induced cyanide-insensitive oxygen consumption. These activities of the tested compounds were also observed in bacterial membrane preparations in a dose-dependent manner. Naphthoquinones stimulated the generation of superoxide anion and hydrogen peroxide. The naphthoquinone effectively acted as the electron acceptors for bacterial diaphorase, which could explain the antibacterial activity of Fusarium naphthoquinones since electron acceptors lead to the stimulation of respiratory activity and the generation of oxygen radical species.

Mitochondrial encephalomyopathies preceded by de-Toni-Debré-Fanconi syndrome or focal segmental glomerulosclerosis

We report two rare cases of mitochondrial encephalomyopathies which were preceded by renal diseases. One occurred in an 11-year-old girl diagnosed with Kearns-Sayre syndrome, which was preceded by de-Toni-Debré-Fanconi syndrome 8 years previously. The other occurred in a 14-year-old girl diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, who developed focal segmental glomerulosclerosis 3 years prior to confirmation of the diagnosis. Tissue from both patient demonstrated morphological abnormalities of the mitochondria in the distal renal tubular epithelium and leiomyocytes of the small renal artery. The present cases illustrate various clinical and morphologic evidence of renal diseases which may further our understanding of mitochondrial encephalomyopathies.

Alteration of ryanodine receptor in the hippocampus CA1 after hemispheric cerebral ischemia

Alterations in ryanodine binding and local cerebral blood flow (LCBF) were examined at 30 minutes and 2 hours post-ischemia in the gerbil brain in order to evaluate the influence of cerebral ischemia on the intracellular channels of Ca2+-induced Ca2+ release (CICR). Severe hemispheric cerebral ischemia was induced by occluding the right common carotid artery. LCBF was measured at the end of the experiment using [14C]iodoantipyrine method, and the ryanodine binding was evaluated in vitro using [3H]ryanodine as a specific ligand for CICR channels. An autoradiographic method developed in our laboratory enabled us to determine both parameters within the same brain. A group of gerbils who underwent a sham procedure served as controls. LCBF was found to be significantly reduced in most of the cerebral regions on the occluded side at both 30 minutes as well as 2 hours post-ischemia. In contrast, a significant reduction in ryanodine binding was noted only in the hippocampus CA1 on the occluded side at 30 minutes and 2 hours after the occlusion. These findings suggest that regionally specific changes of CICR may be the cause of decreased ryanodine binding in the hippocampus CA1, and that these changes may be related to the pathophysiological mechanisms that cause this region to be particularly vulnerable to ischemia.

Phaeophytins from a cell suspension culture of the liverwort Plagiochila ovalifolia

A suspension culture of the liverwort Plagiochila ovalifolia was established from callus tissue induced by culturing spores. From the cultured cells, four phaeophytins were isolated as major components and their structures determined by spectroscopic methods. The phaeophytin derivatives showed antibacterial activity. A major sesquiterpenoid, ovalifoliene, found in the mother plant, was detected in the cultures by GC-mass spectrometry.

Flow threshold for reduction of cyclic AMP binding in the hippocampus CA1 and other brain regions during stroke development in gerbils

The flow threshold for alterations of the in vitro [3H]cyclic AMP (cAMP) binding, an indicator of the total amount of particulate cAMP-dependent protein kinase, was evaluated in the gerbil brain after 30 min, 2 h, and 6 h of unilateral common carotid artery occlusion, respectively. The autoradiographic method developed in our laboratory enabled us to measure the [3H]cAMP binding and local CBF in each region of the same brain. The ischemic flow thresholds for reduction of the cAMP binding in the hippocampus CA1 were 18, 34, and 49 ml 100 g-1 min-1 after 30-min, 2-h, and 6-h ischemia, respectively. These values were higher than those in other regions such as the hippocampus CA, and temporal cerebral cortex in each duration of ischemia. These findings indicate that (a) the ischemic flow threshold for perturbation of the cAMP system may be higher in the hippocampus CA1 than in other brain regions, suggesting that the hippocampus CA1 could be especially vulnerable to acute ischemic stress; and (b) the level of the aforementioned threshold may increase progressively during the time course of ischemia in particular regions such as the hippocampus CA1 and CA3, suggesting that the duration of ischemia exerts a definite influence on the viability of the ischemic neuronal cells in these regions.

[-Clinical features of 10 cases of tuberculous meningitis--with special reference to patient's delay and doctor's delay]

We retrospectively evaluated the clinical findings of 10 cases of tuberculous meningitis who had been admitted to our department from 1987 to 1994. Four patients were male and six were female. All of them were Japanese, and their age ranged from 17 to 74 years old. Regarding the patient's delay, nine patients visited a doctor in 1 to 20 days after the onset of headache, and one patient visited a doctor in 14 days after the onset of general malaise. It is suggested that the patient's delay could not be longer than 3 weeks because of progressively worsening symptoms of tuberculous meningitis such as severe headache and fever. The time interval between the first contact of the patient to a doctor and the commencement of antituberculous therapy (doctor's delay), ranged from 14 to 66 days. When the diagnosis of meningitis was obtained based on the findings of the cerebrospinal fluid (CSF), focal neurological signs including psychological symptoms, cranial nerve palsies and seizure were noted besides meningeal signs or the disturbance of consciousness in 4 patients. The CSF revealed an increase in cell counts with mononuclear cell dominance in 9 patients, but the findings typical for tuberculous meningitis such as increase in total protein content and a decrease in glucose concentration were obtained in only 5 patients. Mycobacterium tuberculosis had not been detected in all cases when the antituberculous chemotherapy was started. Later, it was found to be positive in the CSF sample from only three patients by culture or polymerase chain reaction (PCR) method. When the antituberculous therapy was completed, meningitis was cured without remaining any symptom or sign in all patients. All patients had no active pulmonary tuberculosis when the meningitis was diagnosed, and only one of them had sequels of lung tuberculosis. Four patients had the past history of tuberculosis, and 1 had the familial history of pulmonary tuberculosis. At the first contact to a doctor, seven patients were diagnosed as having common cold or headache related with fever because of the lack of typical signs of meningitis. Similarly three other patients were initially diagnosed as having meningitis due to viral infection or unknown etiology. In summary, it was difficult to obtain the solid diagnosis of tuberculous meningitis at the initial stage of this disease, since the symptoms and signs at its onset often similar to those of common cold or non-specific headache. Therefore, when we see the patients with subacute onset of headache and fever followed by the meningeal signs, tuberculous meningitis should always be included in the list of diseases requiring differential diagnosis. In addition, when tuberculous meningitis is suspected, the antituberculous therapy should be started without any delay.

Regulation of NK activity by the administration of bromocriptine in haloperidol-treated mice

Haloperidol (HPD) is a dopamine receptor blocker and a major causative agent of neuroleptic malignant syndrome. To investigate the influence of HPD on immune responsiveness, the natural killer (NK) cell activity of mice was examined after intraperitoneal administration of HPD for 5 days. NK cell activity was markedly decreased without a depletion of NK cells. Bromocriptine (BROMO), which is used for the treatment of neuroleptic malignant syndrome, also decreased NK cell activity. The suppressive effect on NK cell activity was inhibited by injecting both HPD and BROMO simultaneously. Serum levels of prolactin (PRL) decreased after BROMO injection, although serum PRL level was not decreased after the combined administration of HPD and BROMO agents. The reduction of NK cell activity caused by BROMO and by HPD was prevented by the co-injection of PRL and by a beta-adrenergic blocker, respectively. These results indicate that HPD decreases NK cell activity in a PRL-independent manner and that BROMO decreases it via PRL reduction. It seems that the PRL-independent suppressive effect of HPD on NK cells, which is neutralized by BROMO, is mediated by splenic sympathetic function via the beta-adrenergic receptor system. Therefore, BROMO helps to alleviate the depressed NK cell activity caused by HPD therapy.

Molecular cloning of a 74-kDa regulatory subunit (B" or delta) of human protein phosphatase 2A

Based on amino acid sequence data of a 74-kDa regulatory subunit (B" or delta) of a human heterotrimeric protein phosphatase 2A, a cDNA encoding the subunit was isolated from a human cerebral cortex library. The cDNA had an open reading frame encoding an M(r) 66,138 protein of 570 amino acids. Bacterial expression of the cDNA yielded a protein immunoreactive with antisera specific to the 74-kDa subunit. The predicted primary structure of the subunit had no similarity to already reported sequences of PP2A regulatory subunits including A, B, and PR72. Potential phosphorylation sites for protein kinases A and C, a bipartite motif of putative nuclear localization signal, and SH3 accessible proline-rich domain, and a unique PQ repeat were found in the sequence. The subunit mRNA of about 2.9 kb was ubiquitously expressed in rat tissues.

[Case of a hypertensive centenarian who was able to record 24-hr ambulatory blood pressure]

Our visiting health-check team has followed a 102 year-old centenarian male for 2 years. During this period his blood pressure (BP) was always normal and physically he was almost always in good condition. Physical examinations and blood tests revealed no remarkably abnormal findings. In March, a household BP measuring instrument indicated a rise in systolic BP to more than 190 mmHg. Consequently, his family physician administered a calcium channel blocking anti-hypertensive agent (Nifedipine: Adalat L; 20 mg/day). However, after taking the medicine he felt sick and stopped taking it. During our visit in June, his family requested us to carry out further examination, while continuing to record his BP. His physical and hematological data showed no abnormal findings. We tried to record his normal ambulatory BP during an entire day, first, without drugs, and then followed by medication (Nifedipine 10 mg/day). The results revealed a great gap of pre- and post-medication BP with a maximum of 100 mmHg during the day. We should therefore be much more careful in administering and hypertensive agents such as calcium channel blockers to the very elderly.

Secondary exposure of medical staff to sarin vapor in the emergency room

OBJECTIVE

To clarify the risk of secondary exposure of medical staff to sarin vapor in the emergency room, and to warn emergency room staffs of the hazard.

DESIGN

Retrospective observational survey.

SETTING

Emergency department of a university hospital in a metropolitan area of Japan.

PARTICIPANTS

Fifteen doctors treating victims of a terrorist attack with sarin in the Tokyo subways on the day of the attack.

MEASUREMENTS AND RESULTS

Of the 15 doctors who worked in the emergency room treating the victims, 13 became simultaneously aware of symptoms during the resuscitation of two victims who were exposed to sarin. Among 11 doctors (73%) who complained of dim vision, the pupils were severely miotic (<2 mm) in 8 (73%). Other symptoms included rhinorrhea in eight (53%), dyspnea or tightness of the chest in four (27%), and cough in two (13%). Atropine sulfate was given to six, and pralidoxime was given to one of these six doctors. To decontaminate the emergency room of sarin vapor, ventilation was facilitated and all belongings of the patients were sealed up. None of the doctors noticed worsening of their symptoms thereafter.

CONCLUSIONS

Careful attention to the risks of secondary exposure to toxic gas in the emergency room and prompt decontamination if such exposure should occur are necessary in the case of large-scale disasters caused by sarin.

Flow threshold for enhanced phorbol ester binding in the ischemic gerbil brain

The correlation between regional phorbol ester binding and cerebral blood flow (CBF) was evaluated in the gerbil brain after 2-hour unilateral common carotid artery occlusion. [3H]phorbol 12,13-dibutyrate (PDBu) was used as a specific ligand for estimating the translocation of protein kinase C (PKC), and CBF was determined by the [14C]iodoantipyrine method. A quantitative autoradiographic method permitted concurrent measurement of these two parameters in the same brain. In the ischemia group of the animals, statistically significant, inverse correlations were noted between the CBF and PDBu binding in the hippocampus (CA1 and CA3 regions and dentate gyrus), the caudate-putamen and lateral nuclei of the thalamus. In these regions, the PDBu binding increased progressively as CBF fell below 35-40 ml/100 g/min. On the other hand, the PDBu binding in the cerebral cortices did not show any significant changes even when CBF was decreased to below 35 ml/100 g/min. The above data suggest that (1) the translocation of PKC to the cell membrane may be regionally specific in response to ischemia, and may remain in the regions particularly vulnerable to ischemia such as the hippocampus, caudate-putamen and lateral nuclei of the thalamus in the early ischemic phase; (2) the threshold of CBF below which PKC begins to translocate to the cell membrane in the above regions, may be 35-40 ml/100 g/min in 2-hour ischemia.

[Changes in analgesic levels, plasma concentrations and epidurogram during long-term continuous epidural block]

The change of analgesic levels, plasma concentrations and the radiographical changes of epidural space due to continuous epidural block were studied in 54 patients receiving pain relief. All the patients received 2 ml per hour of 2% lidocaine or 0.5% bupivacaine via the catheter over two weeks. The effect of epidural block was determined on 1, 2, 4, 7, 10 and 14 days, the epidurogram was performed on 1, 7, 14 days, and plasma concentration of lidocaine or bupivacaine was measured on 1, 3, 7, 14 days. We removed catheters in 8 patients because of infection around the catheter, pain in the back during injection, the leakage of anesthetics, and spontaneous removal. The effects and plasma concentrations of epidural block decreased significantly after a week, and the mean segmental number of radiographic spread decreased significantly after two weeks. The decreasing effect or duration of epidural block was due to decrease in spread of anesthetics because of adhesion around the catheter in the epidural space. We conclude that the safety period of continuous epidural block is within 2 weeks.

[Red blood cell parameters of healthy centenarians]

Since the number of centenarians is increasing rapidly in recent years, the establishment of normal ranges in red blood cell (RBC) parameters for healthy centenarians is necessary for diagnostic criteria of anemia. The subjects were 129 centenarians consisting of 27 men (17; healthy, 69; low ADL) and 102 women (33; healthy, 69; low ADL) after excluding centenarians with diseases affecting RBC parameters. The t test was used for statistical evaluation. The mean RBC count for healthy centenarian men was 403 +/- 54.7 x 10(4)/microliters; hemoglobin (Hb) level, 12.4 +/- 1.3 g/dl; hematocrit (Hct), 38.2 +/- 3.9%; MVC, 95.3 +/- 5.3 fl; MCH, 31.4 +/- 2.2 pg; and MCHC, 32.1 +/- 1.1%. Comparable results for healthy centenarian women were as follows: 375 +/- 43.9 x 10(4)/microliters, 11.6 +/- 1.2 g/dl, 36.3 +/- 3.6%, 97.1 +/- 5.3 fl, 31.0 +/- 2.3 pg, and 32.0 +/- 1.3%, respectively. The mean Hb for healthy centenarian women was significantly lower than that for healthy centenarian men. The mean RBC, Hb and hematocrit values for low ADL-centenarian men were lower than the comparable values for healthy centenarian men. Conversely, the mean MCV value for low ADL-centenarian men was higher than that for healthy centenarian men. There was no difference in any RBC parameter between healthy centenarian women and low ADL-centenarian women. In addition, there was no difference in any RBC parameter between centenarian women living in their own homes and those living in old-aged homes. This study demonstrated the normal ranges of RBC parameters for healthy centenarians, and lower RBC, Hb, and Hct values for low ADL-centenarian men.

Chronic transection of post-ganglionic parasympathetic and nasociliary nerves does not affect local cerebral blood flow in the rat

The role of post-ganglionic parasympathetic nerve fibers from the sphenopalatine ganglion and nasociliary nerve fibers from the trigeminal ganglion in the regulation of basal cerebral blood flow (CBF) was examined using rats, which had been divided into three groups; a sham group, a denervation group and a denervation+NG-monomethyl-L-arginine (L-NMMA) group. In the denervation and denervation+L-NMMA groups, unilateral chronic transection of the above nerve fibers had been performed at the ethmoidal foramen (EF) for 2 weeks. In the sham group, the above nerve fibers were only exposed at EF and not severed 2 weeks before the CBF measurement. Local CBF was measured by the [14C]iodoantipyrine autoradiographic method after intravenous administration of saline in the sham and denervation groups or L-NMMA (30 mg/kg) in the denervation+L-NMMA group. No significant difference in CBF was noted on each side in any of the regions between the sham and denervation groups. L-NMMA induced a significant reduction in local CBF on either side in each brain region. Neither the animals which were administered saline nor those with L-NMMA showed any side-to-side differences in local CBF in any of the brain regions examined. These findings suggest that the perivascular nerve fibers running through the EF, which are known to contain substantial nitric oxide synthase (NOS), may not play a pivotal role in the regulation of basal CBF. The reduction in CBF induced by the acute administration of L-NMMA was not affected by the chronic denervation of the above NOS-containing perivascular nerves.

[Chronological study concerning ADL among Okinawan centenarians]

Since 1976 medicobiological and sociological surveys have been carried out upon centenarians in Okinawa. Recently dementia and disability have increased among centenarians. In order to determine the statistical significance, ADL (Activities of Daily Living) scores among Okinawan centenarians were compared; 43 subjects were studied from the 1970's (1976-1980), 99 subjects from the 1980's (1986-1988), and 109 subjects from the 1990's (1992-1994). ADL scores of each centenarian were recorded by the same researchers at the University of the Ryukyus Hospital, based on observation and examination of the centenarians where they lived. Five categories of self sufficiency were defined; completely independent, independent but slow, independent with difficulty, partially dependent, and completely dependent. There were seven physical tasks scored; taking meals, bowel and bladder continence, ability to rise from a toilet, ability to stand, extent of general activities, ability to bathe, and ability to dress oneself. Their sensory functions (auditory acuity and eyesight) and cognitive abilities (comprehension and self-expression) were also scored. Declining rates of total ADL scores were more marked between the 1970's and the 1980's than between the 1980's and the early 1990's. It was also more remarkable in institutionalized centenarians than in centenarians living at home. Decline in physical activities was more distinct in institutionalized than in home-living centenarians. On the other hand, cognitive abilities declined more among centenarian living at home than among institutionalized centenarians. The population of centenarians has increased 23 times over the past 22 years in Okinawa. Human life span has been remarkably extended by advanced medical technology, physically easier life style, and improvement in overall social welfare.(ABSTRACT TRUNCATED AT 250 WORDS)

[Time-course of adenosine deaminase activity in the cerebrospinal fluid in patients with tuberculous meningitis]

The level of adenosine deaminase (ADA) activity in the cerebrospinal fluid is used as a supportive diagnostic measure for tuberculous meningitis. However the time-course of adenosine deaminase activity of the cerebrospinal fluid in patients with tuberculous meningitis remains unknown. The present study describes 4 patients with tuberculous meningitis in whom ADA activity in the cerebrospinal fluid was serially determined in order to clarify the effects of anti-tuberculous chemotherapy on ADA activity in the cerebrospinal fluid. In two of these patients the ADA did not show a high activity in the early stage of the disease. But in all cases the ADA showed a high activity after all, and gradually declined and reached the normal level at approximately 1 month after the initiation of chemotherapy. It seems that the decrease in the ADA activity was seen when T cells in the cerebrospinal fluid returned to a static state upon removal of mycobacterial antigen by the treatment. The level of ADA in the cerebrospinal fluid is considered to be one of the useful measures for diagnosis and follow-up in patients with tuberculous meningitis.

Implication of the common gamma chain of the IL-7 receptor in intrathymic development of pro-T cells

The effects of IL-7 on the growth and differentiation of thymocytes were analyzed using murine fetal thymus organ cultures (FTOC) in the presence of mAbs specific for the conventional IL-7 receptor (IL-7R) and for the common gamma (gamma c) chain. In FTOC, the development of CD4-CD8- double-negative thymocytes to CD4+CD8+ double-positive (DP) and CD4+ or CD8+ single-positive (SP) cells was not completely blocked by adding these mAbs, although cell growth was reduced by the treatment. To define a developing stage sensitive to the mAbs, most immature thymocytes, Pgp-1+ c-kit+ cells, were cultured in 2-deoxyguanosine treated fetal thymus. In the presence of both mAbs in the culture, neither DP nor SP thymocytes developed whereas either of the mAbs partially blocked their development. These results indicate that the gamma c chain is involved in early T cell development as an indispensable subunit of the functional IL-7 receptor complex.

Alteration of inositol 1,4,5-trisphosphate receptor after six-hour hemispheric ischemia in the gerbil brain

In order to evaluate the influence of cerebral ischemia on the inositol 1,4,5-trisphosphate receptor, the alterations of inositol 1,4,5-trisphosphate receptor binding sites and local cerebral blood flow were examined 6 h after occlusion of the right common carotid artery in the gerbil brain. The autoradiographic method developed in our laboratory enabled us to measure both parameters within the same brain. Animals attaining ischemic scores of more than 5, as assessed 1 h after occlusion, were utilized. The local cerebral blood flow was measured 6 h after occlusion by the [14C]iodoantipyrine method. The inositol 1,4,5-trisphosphate binding sites were evaluated in vitro using [3H]inositol 1,4,5-trisphosphate as a specific ligand. The local cerebral blood flow fell below 15 ml/100 g per min in most of the cerebral regions on the occluded side. In contrast, a significant reduction in inositol 1,4,5-trisphosphate binding sites was noted only in the hippocampus CA1 on the occluded side. Inositol 1,4,5-trisphosphate binding tended to decrease when the values of local cerebral blood flow were below 20 ml/100 g per min in this region. On the other hand, the inositol 1,4,5-trisphosphate receptor immunoreactivity in the brain examined with a monoclonal antibody against inositol 1,4,5-trisphosphate receptor protein did not reveal any differences between the ischemia and sham groups on both sides, suggesting that the inositol 1,4,5-trisphosphate receptors may not undergo significant morphological degradation. These findings indicate that the suppression of inositol 1,4,5-trisphosphate binding in the hippocampus CA1 may be attributable to a regionally specific perturbation of the inositol 1,4,5-trisphosphate metabolism in this region.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pure red cell aplasia induced by erythromycin and furosemide effects on in vitro erythroid colony forming unit (CFU-E)]

A 84-year-old man was treated with antibiotics including erythromycin and a diuretic (furosemide) because of acute heart failure and pneumonia. During the treatment, he developed moderate anemia (Hb 8.7g/dl). His anemia improved after the treatment. He again developed marked anemia (Hb 6.3g/dl) during the second treatment with erythromycin and furosemide and received blood transfusions. Bone marrow aspiration study revealed severe erythroid hypoplasia (0.2%). He was referred to our hospital, but he was not treated because his hemoglobin levels and reticulocyte count increased (80%) and his bone marrow showed increased erythroblasts (41.5%). His anemia gradually improved without any treatment. We diagnosed the case as drug-induced pure red cell aplasia (PRCA). We cultured bone marrow cells obtained from the present case and four normal healthy volunteers by a plasma clot method to determine the effects of two drugs on the number of erythroid colony forming unit (CFU-E). Furosemide strongly inhibited the CFU-E colony formation in the patient, but the inhibition effect of erythromycin was moderate. Furthermore, CFU-E was markedly suppressed by a combination of erythromycin and furosemide in both patient and control materials. These results indicate that both furosemide and erythromycin were related to the occurrence of PRCA in this patient.

Pro-T cells in fetal thymus express c-kit and RAG-2 but do not rearrange the gene encoding the T cell receptor beta chain

Ten percent of 15-day fetal thymocytes of mice were Pgp-1+Thy-1lo cells. Half were strongly stained with monoclonal antibodies (mAb) recognizing the oncogene product, c-kit, but were not stained with mAb against non-T cell markers such as B220, Mac-1 and Gr-1. The isolated Pgp-1+c-kit+ thymocytes showed no rearranged bands for V-DJ and D-J of T cell receptor (TcR) beta, but Pgp-1(-)-c-kit- thymocytes showed D-J rearranged bands. Both cells expressed the RAG-2 gene which is required for the V(D)J recombination process. When Pgp-1+c-kit+ thymocytes were cultured in 2-deoxyguanosine-treated alymphocytic fetal thymus, they became TcR-expressing mature type T cells, but this differentiation was reduced by the addition of anti c-kit mAb. These data indicate that Pgp-1+c-kit+ thymocytes are pro-T cells with the potential to differentiate mature T cells in the thymic environment. This study also indicates that c-kit-mediated signals promote the differentiation of thymocytes during their early stages.

Ultrasonographic features of recurrent parotitis in childhood

Six children with recurrent parotitis were studied by ultrasound. Of the 12 parotid glands thus observed, 5 were swollen and 7 were not enlarged. Multiple round hypoechoic areas measuring 2-4 mm in diameter were seen in all 5 enlarged parotid glands and in 5 non-enlarged glands. These small hypoechoic areas were larger than the punctate pools of contrast medium shown by sialography. We consider that these hypoechoic areas represented both peripheral sialectasis and surrounding lymphocytic infiltration. We propose that ultrasonography may be useful for the diagnosis and follow-up of recurrent parotitis in childhood.

A novel quinone antibiotic from Malbranchea cinnamomea TAIM 13T54

A novel quinone antibiotic named malbranicin was isolated from the culture filtrate and mycelium of Malbranchea cinnamomea TAIM 13T54, a thermophilic fungus. The antibiotic was elucidated to be 6-(1-acetylethyl)-2-methoxy-2,5-cyclohexadiene-1,4-dione by spectral analysis. Malbranicin exhibited antimicrobial and cytotoxic activities against Gram-positive bacteria and mammalian cell lines, respectively.