Behavioral and neurological analyses of adult mice carrying null and distinct loss-of-receptor function mutations in protein tyrosine phosphatase receptor type Z (PTPRZ)

Protein tyrosine phosphatase receptor type Z (PTPRZ) is preferentially expressed in the central nervous system as two transmembrane receptor isoforms PTPRZ-A/B and one secretory isoform PTPRZ-S. Ptprz-knockout mice lacking the expression of all three isoforms show behavioral, learning, and neurological abnormalities, including increased exploratory activities to novelty, deficits in spatial and contextual learning, and reduced responses to methamphetamine, relative to wild-type mice. To investigate whether PTPRZ isoforms play distinct physiological roles, we herein performed behavioral studies on two knock-in mouse lines: One expresses the catalytically inactive Cys-1930 to Ser (CS) mutants of PTPRZ-A/B, while the other generated in the present study expresses catalytically active mutants of PTPRZ-A/B lacking the negative regulatory PTP-D2 domain and C-terminal PDZ-binding motif (ΔD2) instead of wild-type PTPRZ-A/-B. In contrast to Ptprz-knockout mice, neither increased responses to novelty in the open field nor memory impairments in the inhibitory-avoidance task were observed in Ptprz-CS or Ptprz-ΔD2 mice. However, the effects of methamphetamine on locomotor activity were significantly weaker in Ptprz-KO mice and CS mutant mice than in wild-type mice, but were normal in ΔD2 mutant mice. Furthermore, microdialysis experiments revealed that methamphetamine-evoked dopamine release in the nucleus accumbens was reduced in Ptprz-KO mice and CS mutant mice. These results suggest that the extracellular region of PTPRZ, including the secretory isoform, is crucial for behavioral responses to novelty and the formation of aversive memories, whereas the PTPase activities of PTPRZ receptor isoforms are involved in regulating the dopaminergic system.

The PTN-PTPRZ signal activates the AFAP1L2-dependent PI3K-AKT pathway for oligodendrocyte differentiation: Targeted inactivation of PTPRZ activity in mice

Protein tyrosine phosphatase receptor type Z (PTPRZ) maintains oligodendrocyte precursor cells (OPCs) in an undifferentiated state. The inhibition of PTPase by its ligand pleiotrophin (PTN) promotes OPC differentiation; however, the substrate molecules of PTPRZ involved in the differentiation have not yet been elucidated in detail. We herein demonstrated that the tyrosine phosphorylation of AFAP1L2, paxillin, ERBB4, GIT1, p190RhoGAP, and NYAP2 was enhanced in OPC-like OL1 cells by a treatment with PTN. AFAP1L2, an adaptor protein involved in the PI3K-AKT pathway, exhibited the strongest response to PTN. PTPRZ dephosphorylated AFAP1L2 at tyrosine residues in vitro and in HEK293T cells. In OL1 cells, the knockdown of AFAP1L2 or application of a PI3K inhibitor suppressed cell differentiation as well as the PTN-induced phosphorylation of AKT and mTOR. We generated a knock-in mouse harboring a catalytically inactive Cys to Ser (CS) mutation in the PTPase domain. The phosphorylation levels of AFAP1L2, AKT, and mTOR were higher, and the expression of oligodendrocyte markers, including myelin basic protein (MBP) and myelin regulatory factor (MYRF), was stronger in CS knock-in brains than in wild-type brains on postnatal day 10; however, these differences mostly disappeared in the adult stage. Adult CS knock-in mice exhibited earlier remyelination after cuprizone-induced demyelination through the accelerated differentiation of OPCs. These phenotypes in CS knock-in mice were similar to those in Ptprz-deficient mice. Therefore, we conclude that the PTN-PTPRZ signal stimulates OPC differentiation partly by enhancing the tyrosine phosphorylation of AFAP1L2 in order to activate the PI3K-AKT pathway.

PKM1 Confers Metabolic Advantages and Promotes Cell-Autonomous Tumor Cell Growth

Expression of PKM2, which diverts glucose-derived carbon from catabolic to biosynthetic pathways, is a hallmark of cancer. However, PKM2 function in tumorigenesis remains controversial. Here, we show that, when expressed rather than PKM2, the PKM isoform PKM1 exhibits a tumor-promoting function in KRASG12D-induced or carcinogen-initiated mouse models or in some human cancers. Analysis of Pkm mutant mouse lines expressing specific PKM isoforms established that PKM1 boosts tumor growth cell intrinsically. PKM1 activated glucose catabolism and stimulated autophagy/mitophagy, favoring malignancy. Importantly, we observed that pulmonary neuroendocrine tumors (NETs), including small-cell lung cancer (SCLC), express PKM1, and that PKM1 expression is required for SCLC cell proliferation. Our findings provide a rationale for targeting PKM1 therapeutically in certain cancer subtypes, including pulmonary NETs.

Oxidative Pathway from Squalene to Geranylacetone in Arthrobacter sp. Strain Y-11

The reaction pathway from squalene to trans-geranylacetone in Arthrobacter sp. strain Y-11 was studied. The enzyme or enzymes catalyzing squalene degradation were found to be membrane bound. Stoichiometric analysis of a cell-free system revealed that the ratio of squalene to trans-geranylacetone changed from 1:2 to 1:1 as the reaction proceeded, indicating two steps in geranylacetone formation. The initial step was found to be oxygenase catalyzed, from the absolute requirement for molecular oxygen in geranylacetone formation and the incorporation of O into geranylacetone under O(2) atmosphere. By using [H]squalene as the substrate, we detected an intermediate in the pathway and identified it as 5,9,13-trimethyltetradeca-4,8,12-trienoic acid by mass spectrometry, infrared spectrometry, nuclear magnetic resonance spectrometry, and chemical synthesis. We deduced that squalene was first oxidatively cleaved to geranylacetone and the intermediate, and that the intermediate was further metabolized to geranylacetone. We also synthesized some of the presumptive metabolites, such as 4,8,12-trimethyltrideca-4,8,12-trien-2-one, and confirmed that they served as active precursors for geranylacetone formation. Based on these lines of evidence, we present here the pathway from squalene to trans-geranylacetone in Arthrobacter sp. strain Y-11.

The expressions of claudin-1 and E-cadherin in junctional epithelium

BACKGROUND AND OBJECTIVE

The epithelium provides an important barrier against microbial invasion. Tight junction structural proteins called claudins are known to contribute to the epithelial cell barrier. Junctional epithelium is located at a strategically important interface between gingival sulcus and is interconnected by desmosomes and gap junctions, but not by tight junctions. Although claudins are tight junction-associated proteins, they are also expressed in the epithelium despite its lack of tight junctions in invertebrates. Therefore, claudins may play an important role in junctional epithelium without tight junctions. E-cadherin is a key molecule in the formation of adherence junctions and desmosomes. In the present study, we aimed to investigate the expressions of claudin-1,claudin-3, claudin-7 and E-cadherin in the junctional epithelium of Fischer 344 rats.

MATERIAL AND METHODS

Gingival tissues from Fischer 344 rats were analyzed by immunohistochemical staining for claudin-1, claudin-3, claudin-7, and E-cadherin.

RESULTS

Intense staining for claudin-1 and E-cadherin were observed in the junctional epithelium. In contrast to claudin-1, claudin-3 was mainly expressed in oral gingival epithelium and claudin-7 could not be detected on immunohistochemical analysis of the rat gingiva.

CONCLUSION

These data suggest that claudin-1 and E-cadherin exist in the junctional epithelium and may play an important role in epithelial barrier function.

Irsogladine maleate counters the interleukin-1 beta-induced suppression in gap-junctional intercellular communication but does not affect the interleukin-1 beta-induced zonula occludens protein-1 levels in human gingival epithelial cells

BACKGROUND AND OBJECTIVE

Irsogladine maleate counters gap junctional intercellular communication reduction induced by interleukin-8 or Actinobacillus actinomycetemcomitans in cultured human gingival epithelial cells. Interleukin-1 beta is involved in periodontal disease. Little is known, however, about the effect of interleukin-1 beta on intercellular junctional complexes in human gingival epithelial cells. Furthermore, irsogladine maleate may affect the actions of interleukin-1 beta. In this study, we examined how interleukin-1 beta affected gap junctional intercellular communication, connexin 43 and zonula occludens protein-1, and how irsogladine maleate modulated the interleukin-1 beta-induced changes in the intercellular junctional complexes in human gingival epithelial cells.

MATERIAL AND METHODS

Human gingival epithelial cells were exposed to interleukin-1 beta, with or without irsogladine maleate. Connexin 43 and zonula occludens protein-1 were examined at mRNA and protein levels by real-time polymerase chain reaction and western blotting, respectively. Gap junctional intercellular communication was determined using the dye transfer method. The expression of zonula occludens protein-1 was also confirmed by immunofluorescence.

RESULTS

Interleukin-1 beta decreased connexin 43 mRNA levels, but increased zonula occludens protein-1 mRNA levels. Irsogladine maleate countered the interleukin-1 beta-induced reduction in gap junctional intercellular communication and connexin 43 levels. However, irsogladine maleate did not influence the increased zonula occludens protein-1 levels.

CONCLUSION

The effect of interleukin-1 beta on gap junctional intercellular communication and tight junctions of human gingival epithelial cells is different. The recovery of gap junctional intercellular communication by irsogladine maleate in the gingival epithelium may be a normal process in gingival epithelial homeostasis.

Role of protein kinase C in calcium-mediated signal transduction

Information from certain extracellular signals, including a group of peptide hormones and some neurotransmitters, appears to flow from the cell surface into the cell interior through two pathways, protein kinase C activation and Ca2+ mobilization, both of which become available by a single ligand-receptor interaction. Under normal conditions protein kinase C is activated by association with membrane phospholipids in the presence of 1,2-diacylglycerol. This diacylglycerol may arise in the membrane only transiently from the receptor-mediated hydrolysis of inositol phospholipids. By using a synthetic permeable diacylglycerol or tumour-promoting phorbol ester (as a substitute for active diacylglycerol) it has been shown that signal passage through this protein kinase pathway is an essential prerequisite, often synergistic to that via the Ca2+ pathway, for full physiological responses, such as transmitter release and exocytosis, to be obtained. Presumably, such a role of protein kinase C may be extrapolated to the activation of many other cellular processes, including membrane conductance, gene expression and some metabolic reactions, as well as to the modulation of other receptor-mediated signal pathways. Some morphological findings with monoclonal antibodies raised against protein kinase C are presented.

Strong growth polarity of yeast prion fiber revealed by single fiber imaging

Using the yeast prion as a model, we have developed a novel system to observe the growth of individual prion fibers directly. NM fragments, the prion-determining region of the yeast protein Sup35p, were labeled by either red or green fluorescent dyes, and the fiber growth was observed under a fluorescence microscope. When green-Sup35NM was added to the preformed fibers made of red-Sup35NM, 70-97% of green fibers grew unidirectionally, from only one end of individual red fibers, whereas the remainder grew from both ends. Similarly, the majority of red fibers grew from only one end of green fibers when the order of addition was reversed. Sonication of preformed fibers to expose fresh ends did not change the results, excluding a possibility of occasional deformation of one end as the reason of the apparent unidirectional growth. These results indicate the polarity of Sup35 prion fibers and impose constraints on the models of fiber growth.

Cell cycle regulation via p53 phosphorylation by a 5'-AMP activated protein kinase activator, 5-aminoimidazole- 4-carboxamide-1-beta-D-ribofuranoside, in a human hepatocellular carcinoma cell line

5-Aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) is an activator of AMP activated protein kinase (AMPK) and a regulator of de novo purine synthesis. There are several earlier reports indicating that AICAR treatment suppresses cell growth via regulation of AMPK or de novo purine synthesis. We found cell growth to be suppressed by AICAR treatment in HepG2 because of p53 accumulation, which was associated with p53-Ser15 phosphorylation. Moreover, a motif very similar to the consensus motif of AMPK phosphorylation was found around p53-Ser15, and Ser15 phosphorylation was detected in AICAR treated HepG2 as was in vitro phosphorylation by AMPK. Our results suggest that AICAR may regulate cell growth via p53 phosphorylation, and also indicate the possibility of p53 phosphorylation.

[Refractory idiopathic cold agglutinin disease successfully treated with intermittent high-dose cyclophosphamide]

A 56-year-old woman, who had been suffering from idiopathic cold agglutinin disease and treated unsuccessfully with prednisolone and cyclosporine A for 6 months, was referred to our hospital in November 1998. She was given methylprednisolone pulse therapy followed by low-dose cyclophosphamide, but her anemia did not improve. We then began administration of intermittent high-dose cyclophosphamide (1,200 mg/day, every 4 weeks), and this resulted in a dramatic increase of her hemoglobin level and improvement of her symptoms. She is currently receiving 500 mg of cyclophosphamide every 2 months and showing a good response. Intermittent high-dose cyclophosphamide therapy can be an effective treatment for refractory cold agglutinin disease.

Cost effectiveness of reducing dioxin emissions from municipal solid waste incinerators in Japan

The main sources of dioxin emissions are municipal solid waste incinerators. The Japanese national government has set an emission standard for dioxins to reduce dioxin exposure levels. In this study, cost-effectiveness analyses are carried out regarding countermeasures that were recently taken and are being taken at municipal solid waste incinerators in Japan. Annual costs were estimated by telephone survey and model calculations. Annual decrease in the incidence of cancer was estimated in three steps. First, the annual decrease in the volume of dioxin emissions was estimated. Next, using a mathematical model, the annual decrease in human exposure was estimated. Finally, the annual decrease in the incidence of cancer was estimated by applying the cancer slope factor. When annual costs are divided by the annual number of life-years saved, cost per life-year saved (CPLYS) was obtained. CPLYS was estimated to be 7.9 million yen for emergency countermeasures and 150 million yen for long-term countermeasures. However, it must be noted that these obtained CPLYSs are highly dependent on the cancer slope factor and should be considered as an upper limit since there may be a cancer effect threshold.

A simple method to estimate the secretion of saliva from minor salivary glands using iodine-starch reaction

OBJECTIVE/HYPOTHESIS

This study was undertaken to detect the faculty of secretion of saliva from minor salivary glands by analyzing a color reaction on a test tape containing iodine and starch that was applied on the lower lip.

STUDY DESIGN

A study involving 63 patients with oral dryness, 7 patients with Sjogren syndrome, and 70 healthy individuals was performed.

METHODS

A test tape (1 x 1 cm) containing iodine and starch was set on the mucosal area anterior to the labia frenulum for 30 seconds. Because the number of blue spots was considered to correspond to the number of ostia of the salivary gland on the lower lip that was examined, the number of blue spots occurring as a reaction of iodine and starch on the test tape was counted and was compared among three groups. In addition, the relationship between the histopathological findings and the number of spots was analyzed.

RESULTS

The average number of spots in the patients with oral dryness (4.52+/-3.18 [mean +/- SD]) was lower than that in healthy individuals (9.49+/-2.52, P <.01), and that in the patients with Sjögren syndrome (2.14+/-1.35) was the lowest among all groups in the study. Moreover, this reduction in the number of spots in those patients was accompanied by histopathological changes of the minor salivary glands.

CONCLUSION

These findings suggest that this simple, noninvasive method can be successfully used for the estimation of the faculty of secretion of saliva from the minor salivary glands.

Primary lymphoma of spermatic cord

Primary lymphomas of spermatic cord are extremely rare. In a review of the world medical literature, until now, only fourteen cases of spermatic cord lymphoma have been reported, and, furthermore, they have a poor prognosis even in patients with stage I disease. Herein, we report a new case of primary non-Hodgkin's lymphoma of the spermatic cord. In August, 1993, 76-year-old man visited an urological hospital with a compaint of a right intrascoral mass, and underwent orchiectomy. Macroscopically no invasive lesion in the testis was observed, and the tumorous lesion was restricted to the epididymis. The histopathological study indicated that he suffered from primary malignant lymphoma of the spermatic cord (B-cell, diffuse medium-sized cell type). As radiographic investigations showed no other invasive lesion, the patient was diagnosed to be in stage IE. He was followed only with clinical observation, and, in August, 1996, relapsed with extensive disease in the abdoninal cavity, and was transferred to our hospital. Fourty months after the orchiectomy, he died of progression of disease irrespective of the salvage radio-chemotherapies given to him.

[Occurrence of angioimmunoblastic T-cell lymphoma six months after onset of Lyme disease]

A 68-year-old man, who had suffered a tick bite one week previously, consulted his home doctor because of fever and an erythematous rash around the bite scar. He underwent a skin biopsy, and Borrelia garinii was detected, from which Lyme disease was diagnosed. He received amoxicillin for two weeks and his symptoms disappeared. After 6 months he noticed swelling of his cervical, axillary and inguinal lymph nodes. A biopsy sample was taken from a left cervical lymph node, and this revealed angioimmunoblastic T-cell lymphoma. The patient achieved a complete remission after chemotherapy. The relationship between Lyme disease and lymphoma is discussed.

Biosynthesis of major plasma proteins in the primary culture of fat body cells from the silkworm, Bombyx mori

Plasma proteins termed "SP1" and "30K proteins" are synthesized by the fat body cells of the silkworm, Bombyx mori, in a sex- and stage-specific manner during larval development. We successfully established a primary culture of the fat body cells in order to investigate the regulatory mechanisms of plasma protein gene expression. The primary cultures of fat body cells contained at least two cell types: small oval cells, and large spherical cells. The cells adhered to and migrated on the cultured dish after plating. By the 7th day of cultivation, the cells clustered to form fat body-like structures, which were maintained for at least 3 months. Plasma proteins were actively synthesized in the primary cultures of the fat body cells isolated from the final instar larvae only when the cells tightly adhered to and clustered on the cultured dish. Immunocytochemical analysis revealed that only 10-15% of the clustered cells synthesized plasma proteins in our culture system, indicating that the primary culture comprises heterogeneous cells that are morphologically and functionally distinct. The patterns of SP1 syntheses in primary cultures faithfully reproduced their sex-dependency in vivo.

Suppression of the lethal effect of acidic-phospholipid deficiency in Escherichia coli by Bacillus subtilis chromosomal locus ypoP

An acidic-phospholipid deficiency caused by the pgsA3 allele that encodes a defective phosphatidylglycerophosphate synthase in Escherichia coli is lethal. The only known mutations that suppress this lethality fully have been related to the major outer-membrane lipoprotein. We isolated a Bacillus subtilis chromosomal locus that suppresses the lethality when harbored in a low copy-number plasmid, without restoring the synthase activity or phospholipid composition to normal. The locus was first recognized to suppress the conditional lethality of E. coli YA5512 (pgsA3) that harbored an unidentified mutation(s), allowing its growth in LB medium but not in media of lower osmolarities. The locus was then found to suppress the lethality of pgsA3 in wild-type E. coli W3110. This locus, named ypoP in the database, had 37% nucleotide identity with the E. coli mprA gene, but the amplification of mprA had no suppressive effect. Plasmid pPOP1 containing ypoP completely prevented the decrease in the amount of a porin protein, OmpF, in the outer membrane and also cell mucoidy caused by pgsA3. The mechanisms underlying these unusual effects are discussed in relation to a putative stress signal(s) generated by the acidic-phospholipid deficiency.

A history of investigation on the mood stabilizing effect of carbamazepine in Japan

A history of investigation on the antimanic and prophylactic effects of carbamazepine in Japan is described. Following the initial open trials in the early 1970s in which the antimanic and prophylactic effects of carbamazepine were indicated for the first time in the world, the mood stabilizing effect was confirmed by the double blind studies which were performed with a multi-institutional cooperation in Japan in the late 1970s. During the course of the double blind trials, the problem of different therapeutic dosages of psychotropic drugs between Japan and Western countries emerged; that is, the doses of chlorpromazine and lithium carbonate, which were used as the control drugs to carbamazepine in the two double-blind group-comparison studies in Japan, were both much lower than the dosage used in most of the Western countries. The low dosage of control drugs made the evaluation of the results of the double blind studies performed in Japan difficult, and caused a delay of publication in the Western journals of the results. Whether the difference is due to biological factors or to psychosocial and cultural factors is an important problem in psychopharmacology and should be investigated further.

Intraluminal tumor of the common bile duct as a metastasis of renal cell carcinoma

A 57-year-old woman was admitted for evaluation of liver dysfunction. A physical examination revealed jaundice and a left abdominal mass, which was diagnosed as being a large renal tumor. Cholangiography showed a smooth filling defect 1 cm in diameter at the common bile duct. Left nephrectomy, and resection of the common bile duct were performed. The pathological diagnosis was metastasis of the common bile duct wall resulting from renal cell carcinoma. Metastatic common bile duct tumors are extremely rare. However, it is important to consider that this is one of the causes of obstructive jaundice.

[Clinical effects of cortisol synthesis inhibition on treatment-resistant depression]

Clinical trial with a steroid suppressive agent, metyrapone, was carried out in 6 patients with treatment-resistant depression (3 patients with major depression and 3 with bipolar disorder). Up to 2,000 mg/day of metyrapone was administered for 4 weeks, and 10 trials of the therapy were done in these patients. Most patients completed the therapy without remarkable side effects. As a result, three patients (6 trials) showed remission within 4 weeks and one patient (one trial) showed a partial response. In the remitted patients, plasma cortisol levels were suppressed below 10 micrograms/dl during the therapy and plasma ACTH levels were elevated. These results indicate that "hypercortisolemia-induced depression" similar to Cushing's disease may be present in patients with treatment-resistant depression.

[Non-Hodgkin's lymphoma presenting as a soft tissue tumor in the connective tissue at the thigh]

A 62-year-old man visited our hospital in July 1993, because of a right thigh mass which had grown gradually since two years previously. Physical examination revealed that the mass at the right thigh region, was elastic soft and about 15 x 10 cm in diameter, without regional lymph node swelling. An ultrasound study showed a hypoechogenic and mesh patterned mass. MRI revealed that the tumor was well defined from subcutaneous adipose tissue and skeletal muscle, indicating that it arose in connective tissue. Angiography demonstrated diffuse hypervascularization of the tumor, and Gallium scintigraphy showed remarkable accumulation at the tumor. Serum IgM was increased, which was proven to be an monoclonal hypergammopathy (IgM, lambda). Histological examination of a biopsied specimen obtained from the thigh mass revealed B cell lymphoma, lymphoplasmacytic cell type. The patient achieved a complete remission after surgical treatment following radiation and combination chemotherapy.

[Endocrinological examination and its clinical significance in manic-depressive illness]

Neuro-endocrine test is one of the useful strategies in examining the pathophysiology of manic-depressive illness (MDI). Unfortunately, however, the pathophysiology of MDI has not yet been clarified and the specific biological markers of MDI have still not been found. In the present paper, a brief general survey as to main clinical points of endocrinological examination and its results towards the hypothalamic-pituitary-adrenal axis, the hypothalamic-pituitary-thyroid axis, the hypothalamic-pituitary-gonadal axis, growth hormone, melatonin, etc. are given and some mentions of biological markers in MDI are made.

Prophylactic effect of mianserin on recurrent depression

The prophylactic effect of mianserin on recurrent depression was studied in a double-blind comparison with an inactive placebo by analyzing the recurrence rate and the number of depressive episodes in 9 mianserin-treated (daily dose 20-60 mg) and 13 placebo-treated patients. The selected patients were those who had a higher incidence of recurrence (more than 2 depressive episodes during the 2 years preceding the study). During the 18-month study period, 4 of 9 mianserin-treated patients and all 13 placebo-treated patients had recurrences. The ratio between patients with recurrence and total patients (recurrence ratio) was lower in the mianserin-treated group throughout the study, and the intergroup difference from the 3rd to the 18th month was significant. In the mianserin-treated group, the frequency of episode recurrence during the study period was significantly lower and the total duration of episodes was significantly shorter than those in the placebo-treated group. The treatments did not differ significantly in safety. These results clearly indicate that mianserin is effective in the prophylaxis of recurrent depressive episodes.

[Anesthesiological management of a patient with primary aldosteronism complicated with hypertrophic cardiomyopathy]

A 49-year-old male with primary aldosteronism, accompanied by hypertrophic cardiomyopathy (HCM), underwent our anesthesiological management for resection of a left adrenal tumor. The preoperative examination revealed hypertension, mild nephropathy and hypokalemia. Spilnolactone treatment was discontinued 3 days before surgery. In the operating room, a Swan-Ganz catheter was inserted for monitoring hemodynamic parameters. Anesthesia was maintained with nitrous oxide-oxygen-isoflurane and vecuronium. During the surgery, prostaglandin E1 and nitroglycerin were used as vasodilators. During surgery, the patient was successfully managed, anesthesiologically. In anesthesiological management of patients with primary aldosteronism, care is needed regarding changes in blood pressure and electolyte levels during adrenalectomy. In cases where aldosteronism is accompanied by HCM, as in the present case, hemodynamic changes can cause a fatal outcome, and hence, carefulness is needed in using anesthetics and drugs which act on the circulatory system.

[A controlled study of the prophylactic effect of mianserin and placebo in recurrent depression]

To examine the prophylactic effect of mianserin on depressive episode, 26 patients with recurrent depression were randomly allocated on a double-blind basis to treatment with either inactive placebo (PL group) or mianserin in daily dose of 20-60 mg (MIA group) for 18 months and the frequencies or durations of depressive episode during the treatment were compared between the two groups. Except for the 4 patients who dropped out, a comparison of the prophylactic effects of the two groups was performed on 9 patients of the MIA group and 13 patients of the PL group. As a result, recurrence of depressive episode occurred in 4 of 9 patients in the MIA group and in all 13 patients in the PL group during the study. The recurrence rate of the depressive episode during the period in the MIA group was always less than that in the PL group, and significant differences were observed between the two groups from the third to the 18th month of the study. Whereas the frequency and duration of the depressive episode in the MIA group during the period of the study were significantly less than those prior to the study, there was no such difference in the PL group. On the other hand, there was no significant difference in the safety between the two groups. From the result of this study, it was suggested that mianserin is effective in the prophylaxis of depressive episode in patients with recurrent depression.

N200 component of event-related potentials in depression

Event-related potentials (ERPs) recorded during a two-tone discrimination (oddball) task were examined in 36 drug-free depressed patients and 36 control subjects. At remission, the ERPs of 12 of the depressed patients were reexamined. In the depressed patients, although a group difference was not detected in the peak latency and amplitude of N200 to rare stimuli, the mean amplitude for the N200 latency range in the difference waves was smaller than in the control subjects. Mismatch negativity (N2a), which was elicited by rare stimuli, was reduced in amplitude; but N2b may have been evoked to frequent stimuli more in the patients than in the control subjects. Depressed subjects may have a deviance in the fully automatic cerebral mismatch process that is assumed to be related to mismatch negativity and provoke the controlled mismatch detection process (presumed to be associated with N2b) even to nontarget frequent stimuli. These findings were observed during remission; however, there was a tendency for the N2b amplitude to decrease and recover toward the level of the control subjects.

The treatment of affective disorder with carbamazepine: prophylactic synergism of lithium and carbamazepine combination

1. In order to examine the prophylactic interaction between lithium and carbamazepine (CBZ), 18 patients who had been treated prophylactically with a combination of lithium and CBZ (combination therapy), lithium alone (Li-therapy), or CBZ alone (CBZ-therapy) were investigated in terms of episode occurrence. 2. The results revealed that the duration of symptoms and the frequency of hospitalization per year were significantly lower in the combination therapy than in both the Li-therapy and the CBZ-therapy. 3. In 7 out of 18 patients, the best prophylactic effect was obtained during combination therapy and none of the parameters measured was definitely inferior to those measured during the two single therapies. 4. During combination therapy, serum lithium level was significantly lower than during Li-therapy in the CBZ responders, and the combination of the two drugs enabled the required concentrations of lithium to be decreased. 5. It was concluded that synergistic action and a decrease in required concentrations of lithium can be expected with the combined use of lithium and CBZ, especially in responders to CBZ.

Phosphorylation of cAMP response element-binding protein, CRE-BP1, by cAMP-dependent protein kinase and protein kinase C

The human recombinant CRE-BP1 was phosphorylated by cAMP-dependent protein kinase and protein kinase C, in vitro. These two protein kinases modified distinct serine residues of CRE-BP1. Ser-62 downstream of a putative metal finger structure of CRE-BP1 was the phosphorylation site by cAMP-dependent protein kinase, whereas two serine residues, Ser-340 and Ser-367, located in the basic region of this protein were the major protein kinase C phosphorylation sites. It seems possible that transcriptional and DNA-binding activities of CRE-BP1 are regulated by phosphorylation with these protein kinases.

Protein kinase C in rat brain synaptosomes. Beta II-subspecies as a major isoform associated with membrane-skeleton elements

A small fraction (approximately 5%) of protein kinase C (PKC) in the adult rat brain synaptosomes is tightly associated with Triton X-100-insoluble components (most likely membrane-skeleton elements), and is solubilized only after denaturation with sodium dodecyl sulfate. The kinase domain of this PKC can be released as a soluble form after limited proteolysis with calpain, whereas the regulatory domain which binds phorbol ester remains insoluble. The PKC in this fraction was identified as the beta II-subspecies or its related molecule. Presumably, this enzyme subspecies is responsible for the phosphorylation of a major PKC substrate protein, growth-associated protein-43, which is located in nerve endings as well as in growth cones in association with the membrane-skeleton elements.

Phosphorylation of type II (beta) protein kinase C by casein kinase II

Rat brain type II (beta) protein kinase C (PKC) was phosphorylated by rat lung casein kinase II (CK-II). Neither type I (gamma) nor type III (alpha) PKC was significantly phosphorylated by CK-II. CK-II incorporated 0.2-0.3 mol of phosphate into 1 mol of type II PKC. This phosphate was located at the single seryl residue (Ser-11) in the V1-variable region of the regulatory domain of the PKC molecule. A glutamic acid cluster was located at the carboxyl-terminal side of Ser-11, showing the consensus sequence for phosphorylation by CK-II. The velocity of this phosphorylation was enhanced by the addition of Ca2+, diolein, and phosphatidylserine, which are all required for the activation of PKC. Phosphorylation of casein or synthetic oligopeptides by CK-II was not affected by Ca2+, diolein, or phosphatidylserine. Available evidence suggests that CK-II phosphorylates preferentially the activated form of type II PKC. It remains unknown, however, whether this reaction has a physiological significance.

H1 histone stimulates limited proteolysis of protein kinase C subspecies by calpain II

Limited proteolysis of protein kinase C (PKC) subspecies with Ca2(+)-dependent neutral protease II (calpain II) was remarkably stimulated by basic polypeptides, such as H1 histone and poly-L-lysine. This stimulatory effect was observed for proteolysis of the active form of PKC, which was associated with phospholipid and diacylglycerol. The inactive form of PKC was far less susceptible to proteolysis, both in the presence and absence of the basic polypeptides. The basic polypeptides did not appear to interact with calpain II, but made the PKC molecule more susceptible to proteolysis. The relative rates of cleavage of type I (gamma), II (beta), and III (alpha) PKC were 2:2:1. The available evidence suggests that, like calpain I, calpain II may also contribute to the down-regulation or depletion of PKC.

Limited proteolysis of protein kinase C subspecies by calpain: stimulation by basic polypeptides

Limited proteolysis of Protein Kinase C (PKC) subspecies by Ca(2+)-dependent neutral protease II (calpain II) was remarkably stimulated by the presence of basic polypeptides, such as H1 histone, protamine, poly-L-arginine, and poly-L-lysine. The stimulatory effect of basic polypeptides was observed for proteolysis of the active form of PKC which was associated with diacylglycerol and phospholipid. The inactive form of PKC was far less susceptible to proteolysis, either in the presence or absence of the basic polypeptides. The basic polypeptides did not appear to interact with calpain II, but caused a conformational change in PKC to make the kinase molecule more susceptible to proteolysis. The relative rates of cleavage of the active form of types I (gamma), II (beta), and III (alpha) PKC by calpain II in the absence and presence of basic polypeptides were 100:48:23 and 100:100:50, respectively. Available evidence suggests that, like calpain I, calpain II may also contribute to the down-regulation or depletion of PKC.

Abnormalities in event-related potentials, N100, P200, P300 and slow wave in schizophrenia

Event-related potentials were recorded in 54 schizophrenics and 88 age-matched controls during a two-tone discrimination (odd ball) task. All the subjects were free from medication. In the schizophrenics, the mean amplitudes of the N100, P300 and Slow Wave latency ranges were decreased, and the amplitude of the P200 latency range was greater than that for the controls. These reductions and the increase were found both for the ERPs elicited by rare target stimuli and for those elicited by frequent nontarget stimuli. The peak latency of N200 to rare stimuli was more prolonged in the schizophrenics than in the controls. This finding confirms the prolongation of N200 latency that Brecher et al. (1987) found for a different visual stimuli task. Neither the N100 nor P300 latency differed between the two groups.