Role of pyruvate in ischaemia-like conditions on cultured neurons

In vitro, it is known that neurons in serum free mediums survive in the absence of glucose if pyruvate is present. We exposed cultured neurons on poly-L-lysine coated dishes to 6 different concentrations of pyruvate ranging from 0 to 1000 microM combined with glucose-supplement and normoxia (controls), glucose-deprivation and normoxia (hypoglycaemia), glucose-supplement and hypoxia (hypoxia), and glucose deprivation and hypoxia (ischaemia-like conditions) for 4 h. In all these conditions, lowering pyruvate below 250 microM led to a significant decrease of neuronal survival. Even in controls, there was no surviving neurons exposed to 0 microM of pyruvate. Glucose deprivation alone did not essentially influence the survival rate. Regardless of glucose deprivation, hypoxia led to an additional 23%-100% decrease of neuronal survival. When neurons were cultured above the astrocyte layers, neurons were much more tolerant with exposure to 0 microM of pyruvate for 4 h as compared to neurons on poly-L-lysine. The results indicate that pyruvate rather than glucose is essential for the energy supply to cultured neurons, probably because these neurons are immature and possess yet little capability to gain energy from glycolysis. Astrocytes may protect neurons from pyruvate deprivation by providing energy to neurons. In neuron rich culture, ischaemia is much better simulated by hypoxia-pyruvate deprivation rather than hypoxia-glucose deprivation.

Effects of iodine pretreatment of sections upon immunogold-silver staining in light microscopic immunohistochemistry

Effects of Lugol's iodine pretreatment upon immunogold-silver staining were examined in terms of the intensification of the reaction products obtained by physical development. Iodine pretreatment has diminished the duration necessary for the development, whereas the staining reaction of an appropriate intensity, could hardly be obtained by the pretreatment. In addition, essential staining reactions tended to be accompanied by marked nonspecific silver precipitations. It is concluded that iodine pretreatment should either be omitted or used with cautions in immunogold-silver staining procedures for the precise detection of antigenic sites.

[Two cases of malignant effusion treated successfully by loco-regional administration of carboplatin]

We encountered two cases of malignant effusion treated successfully by loco-regional administration of carboplatin (CBDCA). One case was a 60-year-old male showing recurrent non-small cell lung cancer (adenocarcinoma) with pericarditis carcinomatosa. A drainage from the pericardial cavity was performed and a total dose of 600 mg (single dose, 300 mg) of CBDCA was administered into the cavity. Malignant effusion disappeared and radiographic improvement was also observed. No pericardial effusion was observed for about 4 months after the loco-regional treatment, till he died of lung cancer. Another case was a 58-year-old male having invasive thymoma (mixed cell type) with pleuritis carcinomatosa. He received palliative radiation therapy and systemic cancer chemotherapy concurrently. As a loco-regional therapy, drainage from the pleural cavity was performed, and 300 mg of CBDCA and 10 KE of OK-432 were administered into the cavity. A remarkable reduction of pleural effusion was observed after the therapy. No increase of pleural effusion has been observed radiographically for about 18 months, and the patient is still alive with the tumor. The side effects due to loco-regional administration of CBDCA were quite tolerable in both cases.

[Clinical trials of TAE using micro-coil coated with n-butyl 2-cyanoacrylate and lipiodol]

Clinical trials of TAE using microcoils (Target, USA) coated with n-butyl 2-cyanoacrylate and lipiodol were performed. The procedures were as follows. First, a small amount of lipiodol was injected into a Tracker 18 catheter. Secondly, a microcoil coated with n-butyl 2-cyanoacrylate and lipiodol was inserted into the microcatheter. Thirdly, a small amount of lipiodol was again administered into the catheter just behind the coil. Finally, the coil was pushed safely out from the catheter with a special guidewire. With this method, excellent occlusion of small arteries was obtained. There were no complications.

Functional and high level expression of human dopamine beta-hydroxylase in transgenic mice

Dopamine beta-hydroxylase (DBH; EC 1.14.17.1) catalyzes the production of the neurotransmitter and hormone norepinephrine in the third step of the catecholamine biosynthesis pathway. Transgenic mice were generated with multiple copies of a human DBH minigene construct containing the full-length cDNA connected downstream of the 4-kilobase upstream promoter region to achieve overexpression of DBH. Human DBH mRNA and immunoreactivity were detected tissue-specifically in the brain and adrenal gland of these transgenic mice. The transgene products were correctly processed to a glycosylated mature polypeptide with a molecular mass of 72 kDa and existed in the secretory vesicles as both soluble and membrane-bound forms. We detected a marked increase in DBH activity in various catecholamine-containing tissues of the mice that occurred as a consequence of expression of the catalytically active human DBH enzyme. However, in these transgenics the steady-state levels of norepinephrine and epinephrine were normally maintained without the acceleration of the catecholamine turnover rate, suggesting that there are some regulatory mechanisms to preserve a constant rate of norepinephrine synthesis in spite of the increased amount of DBH protein. These transgenic mice with the minigene construct provide one approach to study the mechanisms underlying biogenesis of the DBH polypeptide and regulation of norepinephrine synthesis.

Sequence homology of Chinese hamster metallothionein genes I and II to those of the mouse and rat, and their amplification in Cd-resistant cells

The metallothionein (MT) I and II genes were isolated from Chinese hamster cells and sequenced. The MT-II gene is located about 6 kb upstream of the MT-I gene and their arrangement is similar to those of the mouse and rat MT genes. The sequence of the Chinese hamster MT-I gene is highly homologous to those of the mouse and rat, particularly in their promoter regions of MT-I. However, the promoter region of MT-II has less homology with those of the mouse and rat due t to insertions and deletions. The MT-I and MT-II genes were equally amplified 4-8-times in the Cd-resistant Chinese hamster cells, suggesting that both genes are included in the same amplification unit. Cytogenetic analysis of Cd-resistant cells by in situ hybridization showed that they are randomly integrated into multiple sites on the chromosomes.

Insulin-induced activation of glycerol-3-phosphate acyltransferase by a chiro-inositol-containing insulin mediator is defective in adipocytes of insulin-resistant, type II diabetic, Goto-Kakizaki rats

Type II diabetic Goto-Kakizaki (GK) rats were insulin-resistant in euglycemic-hyperinsulinemic clamp studies. We therefore examined insulin signaling systems in control Wistar and diabetic GK rats. Glycerol-3-phosphate acyltransferase (G3PAT), which is activated by headgroup mediators released from glycosyl-phosphatidylinositol (GPI), was activated by insulin in intact and cell-free adipocyte preparations of control, but not diabetic, rats. A specific chiro-inositol-containing inositol phosphoglycan (IPG) mediator, prepared from beef liver, bypassed this defect and comparably activated G3PAT in cell-free adipocyte preparations of both diabetic GK and control rats. A myo-inositol-containing IPG mediator did not activate G3PAT. Relative to control adipocytes, labeling of GPI by [3H]glucosamine was diminished by 50% and insulin failed to stimulate GPI hydrolysis in GK adipocytes. In contrast to GPI-dependent G3PAT activation, insulin-stimulated hexose transport was intact in adipocytes and soleus and gastrocnemius muscles of the GK rat, as was insulin-induced activation of mitogen-activated protein kinase and protein kinase C. We conclude that (i) chiro-inositol-containing IPG mediator activates G3PAT during insulin action, (ii) diabetic GK rats have a defect in synthesizing or releasing functional chiro-inositol-containing IPG, and (iii) defective IPG-regulated intracellular glucose metabolism contributes importantly to insulin resistance in diabetic GK rats.

Cloning and expression of cDNA for arginine-specific ADP-ribosyltransferase from chicken bone marrow cells

Two arginine-specific ADP-ribosyltransferase cDNAs (designated AT1 and AT2) were cloned from chicken bone marrow cells. Each cDNA encodes a different peptide of 312 amino acid residues. Homology of deduced amino acid sequences between AT1 and AT2 was 78.3%. We found all six combined peptide sequences of 222 amino acid residues derived from purified chicken heterophil ADP-ribosyltransferase (Mishima, K., Terashima, M., Obara, S., Yamada, K., Imai, K., and Shimoyama, M. (1991) J. Biochem. (Tokyo) 110, 388-394) in the deduced amino acid sequence of AT1, with two amino acid mismatches. Arginine-specific ADP-ribosyltransferase activity was detected in culture medium of COS 7 cells transiently transfected with AT1 cDNA, while activity from the cells transfected with AT2 cDNA was found in both culture medium and cell lysate. AT1 transferase required 2-mercaptoethanol for the activity. The activity was inhibited in the presence of NaCl while AT2 enzyme was activated by either agent. On zymographic in situ gel analysis, estimated molecular masses of the AT1, AT2 and purified chicken heterophil transferases were 32, 34, and 27.5 kDa, respectively. Northern blot analysis with specific probes to AT1 or AT2 cDNAs revealed about a 1.5-kilobase message in chicken bone marrow cells but no signals were observed in heterophils, spleen, and liver of chicken or human HL-60 cells. Highly conserved regions were observed among the deduced amino acid sequences of AT1, AT2, rabbit skeletal muscle transferase, and rodent T-cell surface antigen RT6s.

In vivo activity of bleomycin incorporated with biodegradable poly-d,l-lactic acid and implanted in the mediastinum of dogs

The possible usefulness of bleomycin incorporated with biodegradable poly-d, l-lactic acid (BLM-PLA) for targeting chemotherapy for esophageal cancer was studied in vivo. Local levels of BLM after administration were compared with those after injection of BLM-SOL, an aqueous solution of BLM. BLM-PLA or BLM-SOL was administered into the upper mediastinum under a right thoracotomy in 36 mongrel dogs. On days 10, 20, and 30 after administration, connective tissues, lymph nodes, lung, liver, kidney, and spleen were removed, and BLM activity was measured. High activity of BLM was detected for 30 days after BLM-PLA administration in both the connective tissues and the lymph nodes, compared with BLM-SOL administration. BLM activity was low in the other organs after BLM-PLA administration. BLM in the blood was significantly lower after administration of BLM-PLA than BLM-SOL. The results indicate that BLM-PLA may become a useful tool in targeting chemotherapy for esophageal cancer.

Molecular control of melanogenesis in malignant melanoma: functional assessment of tyrosinase and lamp gene families by UV exposure and gene co-transfection, and cloning of a cDNA encoding calnexin, a possible melanogenesis "chaperone"

Melanogenesis is a cascade of events significantly controlled by regulatory genes which are associated with the melanosomal membrane. This report introduces our current research efforts dealing with (a) the gene and protein expressions of tyrosinase and Lamp (lysosome-associated membrane protein) families by human melanoma cells after repeated exposures to UV light, (b) the coordinated alterations in the expression of the Lamp family gene and its encoding product after transfection of two genes of the tyrosinase family in human melanoma cells and (c) cloning and sequencing of a Ca(2+)-binding phosphoprotein, calnexin, which could be a candidate as a chaperone for sorting and maturation of tyrosinase and Lamp family glycoproteins in melanogenesis cascade. Our UV exposure study, as well as gene transfection and antisense hybridization experiments, has clearly indicated a marked and coordinated interaction of the Lamp-1 gene with the tyrosinase and TRP-1 genes in this process. We propose that melanogenesis is controlled at least by two major gene family products, i.e., (a) the tyrosinase family of tyrosinase, TRP-1 and TRP-2, and the Lamp family of Lamp-1, Lamp-2 and Lamp-3. These two gene families probably derived from primordial melanogenesis-associated genes which are common or closely related to each other.

Role of nuclear histone-H1 kinase in regeneration of rat liver

The activities of nuclear histone-H1 kinase and C-kinase as well as the amount of phosphate bound to histone-H1 following partial hepatectomy were studied in rat. It was found that the nuclear histone-H1 kinase activity increased twice within 80 h, first 20 to 30 h, and second at 50 to 70 h after partial hepatectomy. The timing of increase of the enzyme activity correlated with increased amount of bound phosphate. On the other hand, the increase of the C-kinase activities occurred between 5 and 15 h after partial hepatectomy. Antibodies raised against human cdk2, human cyclin-A and mouse cdc2 kinase showed no detectable effect on the nuclear histone H1 kinase activity. These results suggest that phosphorylation of histone-H1 in liver regeneration may be catalysed by a putative kinase(s).

Mapping of the human C3G gene coding a guanine nucleotide releasing protein for Ras family to 9q34.3 by fluorescence in situ hybridization

C3G, a human guanine nucleotide releasing protein for Ras protein, was mapped to human chromosome 9q34.3 by fluorescence in situ hybridization with R-banded chromosomes. C3G was originally identified as one of the CRK-binding proteins, similar to c-abl (9q34.1). Our result suggests that the downstream factors of Crk are localized in close proximity on chromosome 9.

[Motor developmental screening test for mental retardation: evaluations of sensitivity and specificity]

For the purpose of early detection and early habilitation for developmentally handicapped children, we started medical screening for pediatric neurological diseases among children in Sodegaura City, Chiba prefecture, since 1978. We calculated sensitivity, the rate of judging abnormal children to be abnormal, specificity, the rate of judging normal children to be normal and positive predictive values, the rate of judging abnormal children who have abnormal sign, of sitting alone at nine months of age whether an infant is MR or not. The sensitivity was 70.0%, the specificity was 98.3% and the positive predictive value was 26.5%, all of them were high rates. Therefore we conclude that children who can not sit alone until nine months of age are possibly mentally retarded and the capability of sitting alone or not at nine months of age is an useful screening test for the purpose of early detection of mentally retarded children.

[Distribution of the 70kD stress protein in corneas with alkali burns]

The immunolocalization of 70kD stress-protein (SP 70) was investigated in white rabbit corneas with alkali burns. Corneal alkali burn injuries were induced with 6 mm circular filter paper discs soaked in 1N NaOH. Corneas of 1, 3, 5, and 7 days after alkali injury were immunostained with mouse monoclonal anti-SP 70 antibody. In the control rabbit cornea, immunostaining for SP 70 was observed in the nuclei of the basal cells and of the wing cells. On day 1 after alkali injury, total epithelial defect was observed. Immunostaining for SP 70 was not seen in corneas with total epithelial defect. Three days after injury, epithelial resurfacing with corneal edema was observed. Basal cells showed immunostaining for SP 70 in their nuclei and cytoplasm. Five days after injury, irregular basal cells and a few wing cells with cytoplasmic processes were recognized. Both cells showed diffuse cytoplasmic and nuclear immunostaining for SP 70. Seven days after injury, the corneal wound was healed, and SP 70 was observed in the nuclei of the epithelial cells again. It appears that SP 70 has a role in corneal epithelial healing after alkali burn injury.

Temporal bone pathology in patients without caloric response

Pathologies of serial sections of 9 temporal bones from 6 patients without caloric response were studied. The patients died of epipharyngeal cancer, middle ear cancer, chronic renal failure with DIC, pancreatic cancer with DIC, multiple brain metastasis of pancreatic cancer, and leukemia. Under light microscopy, 8 ears showed pathologies in the vestibular end organs and the nerves. Possible causes of the lack of caloric responses in the 8 ears were endolymphatic hemorrhage, labyrinthitis, leukemic infiltration in the labyrinth, degeneration or disappearance of the vestibular sensory cells, reduction in the number of vestibular nerve fibers, and/or brainstem lesions. The remaining one ear did not show abnormal findings in the vestibular end organs or the nerves, but the patient had brainstem lesions. Four types of temporal bone pathologies were observed according to the lesion site responsible for the lack of caloric response; i) sensory type, ii) neural type, iii) mixed type and iv) central type.

Immunoreactive tenascin in tumours of salivary glands: evidence for enhanced expression in tumour stroma and production by tumour cells

Tenascin, a large molecular weight extracellular glycoprotein expressed at the epithelial-mesenchymal interface during morphogenesis in embryo, wound healing and in the stroma of various benign and malignant tumours was evaluated in a series of primary epithelial tumours of salivary glands using a monoclonal antibody. Normal salivary glands (n = 5) had linear delicate band-like immunoreactive tenascin in relatively large excretory or intralobular ducts. Pleomorphic adenomas (n = 40) had heterogeneity of expression in modified myoepithelial cell-associated myxoid, hyaline and chondroid areas. Warthin's tumours (n = 10) had a linear immunoreactivity profile of tenascin just adjacent to the basal cells of the epithelial tumour component. A heterogeneity of expression with intense to low or negative stromal immunoreactivity was observed in adenoid cystic carcinomas (n = 8), mucoepidermoid carcinomas (n = 8), epithelial-myoepithelial carcinomas (n = 4), polymorphous low-grade carcinomas (n = 3), papillary cystadenocarcinomas (n = 15) and undifferentiated carcinomas (n = 3). In addition, small cystic spaces or lumens of epithelial-lined tubulo-ductal structures in numerous salivary tumours had positive immunoreactivity for tenascin, suggesting its production by the epithelial tumour component. An enhanced expression of tenascin in salivary tumours suggests a role of this protein in the stromal remodelling and tumour growth.

Apolipoprotein E epsilon 4 allele distribution in alcoholic dementia and in Alzheimer's disease in Japan

The apolipoprotein E epsilon 4 allele has been associated with both familial and sporadic Alzheimer's disease (AD). Given its possible role in nerve repair and growth, it is plausible that apolipoprotein E may be a common denominator in the pathogenesis of several dementing diseases. Therefore, we investigated epsilon 4 frequencies in demented and nondemented alcoholics, as well as in patients with sporadic AD and controls in Japan. No significant differences in allele frequencies was found between demented and nondemented alcoholics and controls, while a significant association was demonstrated between AD and the epsilon 4 allele. These results support a specific role of epsilon 4 in the pathogenesis of AD, rather than a more general role for epsilon 4 in dementing illnesses.

Chelation of copper reduces inhibition by oxidized lipoproteins of endothelium-dependent relaxation in porcine coronary arteries

We examined the effect of dialyzing oxidized low-density lipoprotein (oLDL) against Krebs-Ringer solution, in the absence (yielding d-oLDL) or presence (yielding EDTA-oLDL) of ethylenediamine tetraacetic acid (EDTA), to investigate the mechanism that underlies the inhibition of endothelium-dependent relaxation (EDR) by o-LDL. Oxidation of LDL by exposure to Cu2+ resulted in the formation of a thiobarbituric acid-reacting substance (TBARS) and lipid hydroperoxide (LPO). At a concentration of 5 mg/dl, d-oLDL markedly attenuated EDR in the porcine coronary artery. Analysis of d-oLDL by gel filtration revealed that TBARS was ditributed in both the lipoprotein and the aqueous phases, whereas LPO was present only in the lipoprotein particles. Lysophosphatidylcholine (LPC), which has been suggested to be responsible for the impairment of EDR by oLDL, was present not only in the lipoprotein but also in the aqueous phase. However, EDR inhibitory activity was observed only in the oLDL particles, not in the aqueous phase. Almost all Cu2+ associated with the oLDL particles was removed by dialysis of oLDL against Krebs-Ringer solution containing EDTA. EDTA-oLDL or native LDL, at concentrations as high as 75 mg/dl, exerted only a moderate inhibitory action on EDR, Both TBARS and LPO in EDTA-oLDL were distributed only in the lipoprotein particles, not in the aqueous phase. These results demonstrate that the impairment of EDR by oLDL is related both to LPO and to transition metal ions such as Cu2+ associated with the lipoprotein particles, not to the amount of the TBARS or negative charge, and that factors other than LPC may affect EDR.

Transient contraction of muscle fibers on photorelease of ATP at intermediate concentrations of Ca2+

We isometrically activated skinned fibers in rigor by flash photolysis of caged ATP at various [Ca2+] at 8 degrees C. On release of ATP, tension initially decreased with the same time course at all [Ca2+]. At high [Ca2+] (pCa < or = 5.8), tension rose to the steady-state plateau after the brief relaxation. When the [Ca2+] was intermediate (7.0 < or = pCa < or = 6.0), tension temporarily overshot the final steady-state level. The half-time during this tension transient was longer at higher [Ca2+]. The transient contractions could be simulated by a simple kinetic model: R + ATP-->Q, and X<-->Q<-->A, where R, X, and A are the rigor, relaxed, and active-tension states, respectively; Q is a "pre-active" state where tension is very low; and Ca2+ affects only the X-Q transition. This scheme was also useful for predicting the tension transients in Ca(2+)- and P(i)-jump experiments at various [Ca2+]. ADP enhanced the Ca2+ sensitivity of the ATP-induced transient contraction, which was not in the scope of the model.

Beta 1-adrenergic mechanism is involved in stress-induced increase in arousal

It has been shown that 1 h restraint shortens pentobarbital (PbNa)-induced sleeping time and that brain corticotropin-releasing hormone (CRH) is involved in the mechanism by which restraint shortens. PbNa-induced sleeping time. The present study was designed to further examine the mechanism of the antagonistic effect of 1 h restraint on PbNa in rats. Intracerebroventricular (i.c.v.) administration of propranolol and metoprolol, but not butoxamine reversed the shortening of PbNa-induced sleeping time by 1 h restraint. The i.c.v. administration of phentolamine blocked the shortening of PbNa-induced sleeping time by restraint, while the same dose of phentolamine prolonged the sleeping time in unrestrained rats. Atropine did not affect the PbNa-induced sleeping time in restrained rats. These results suggest that in addition to CRH, the brain beta 1-adrenergic system is involved in the restraint stress-induced increase in arousal.