Structures of genes encoding phospholipase A2 inhibitors from the serum of Trimeresurus flavoviridis snake.

Inhibitors (PLIs) against snake venom gland phospholipases A2 (PLA2s) have been found in their sera. A cDNA encoding a PLI from Trimeresurus flavoviridis (Tf, habu snake, Crotalinae) serum, cPLI-A, was isolated from the Tf liver cDNA library and sequenced. Northern blot analysis with cPLI-A showed that PLIs are expressed only in liver. Genes for PLIs, gPLI-A and gPLI-B, were isolated from the Tf genomic DNA library and their nucleotide (nt) sequences were determined. The genes consisted of four exons and three introns, and exon 4 encoded the carbohydrate recognition domain (CRD)-like motif. Comparison of the nt sequences between gPLI-A and gPLI-B showed that these genes are highly homologous, including introns, except that exon 3 is rich in nonsynonymous nt substitutions which are almost four times as frequent as synonymous nt substitutions. This evolutionary feature of PLI genes is different from that of venom gland PLA2 isozyme genes in which nonsynonymous nt substitutions are spread over the entire mature protein-coding region.

Accelerated evolution of Trimeresurus okinavensis venom gland phospholipase A2 isozyme-encoding genes.

Three Trimeresurus okinavensis (To; himehabu snake, Crotalinae) venom gland phospholipase A2 (PLA2) isozymeencoding genes, gPLA2-o1, gPLA2-o2 and gPLA2-o3, were isolated from its genomic DNA library. The nucleotide (nt) sequence analysis revealed that two of the three genes (gPLA2-o2 and gPLA2-o3) occasionally have been converted to inactivated genes by introduction of one base insertion or substitution. It was confirmed from Southern blot analysis that the To haploid genome contains only three venom gland PLA2 isozyme genes herein isolated. Comparison of these genes showed that nonsynonymous nt substitutions have occurred more frequently than synonymous nt substitutions in the protein-coding regions, except for the signal-peptide coding domain, implying that To venom gland PLA2 isozyme genes have evolved via accelerated evolution. Such an evolutionary feature of To venom gland PLA2 isozyme genes proves the general universality of accelerated evolution previously drawn for venom gland PLA2 isozyme genes of other crotalinae snakes. The variability in the mature protein-coding regions of three To venom gland PLA2 isozyme genes appears to have been brought about by natural selection for point mutations.

Structures of genes encoding TATA box-binding proteins from Trimeresurus gramineus and T. flavoviridis snakes.

A cDNA encoding the Trimeresurus gramineus (Tg; green habu snake) TATA-box-binding protein (TgTBP) was cloned and sequenced. The cDNA encodes a 33-kDa protein with an extensive sequence similarity to those derived from other organisms, except for the N-terminal domain. Genes encoding TgTBP and Trimeresurus flavoviridis (Tf; habu snake) TBP (TfTBP) were isolated using a TgTBP cDNA and their nt sequences were determined. They are the first TBP genes entirely sequenced in higher animals. Both genes span over 15 kb and are constructed from eight exons and seven introns. Comparison of the loci of introns on the aligned amino-acid sequences of TBP from six organisms (Tg, Tf, mouse, Arabidopsis thaliana, Schizosaccharomyces pombe and Acanthamoeba castellanii) indicated that there are three highly conserved loci in the C-terminal domain.

Accelerated evolution of crotalinae snake venom gland serine proteases.

Eight cDNAs encoding serine proteases isolated from Trimeresurus flavoviridis (habu snake) and T. gramineus (green habu snake) venom gland cDNA libraries showed that nonsynonymous nucleotide substitutions have accumulated in the mature protein-coding regions to cause amino acid changes. Southern blot analysis of T. flavoviridis genomic DNAs using two proper probes indicated that venom gland serine protease genes form a multigene family in the genome. These observations suggest that venom gland serine proteases have diversified their amino acid sequences in an accelerating manner. Since a similar feature has been previously discovered in crotalinae snake venom gland phospholipase A2 (PLA2) isozyme genes, accelerated evolution appears to be universal in plural isozyme families of crotalinae snake venom gland.

Effect of dipotassium clorazepate on amygdaloid-kindling and comparison between amygdaloid- and hippocampal-kindled seizures in rats.

We examined the effect of dipotassium clorazepate (7-chloro-1, 3-dihydro-2-oxo-5-phenyl-1H-1, 4-benzodiazepine-3-carboxylate potassium hydroxide), an antianxiety drug, on amygdaloid kindling and compared its effects for 7 successive days on amygdaloid- versus hippocampal-kindled seizures, using the rat kindling model of epilepsy. Dipotassium clorazepate at 5 mg/kg significantly delayed amygdaloid kindling. The contralateral cortical after-discharge duration in the dipotassium clorazepate-treated group was significantly shorter than the after-discharge duration in the amygdala in the first seven stimulations, whereas it was significantly shorter only in the first three stimulations in the control group, indicating that dipotassium clorazepate suppressed the spread of seizure activity from focus to contralateral cortex. Dipotassium clorazepate suppressed amygdaloid-kindled seizures at 2 and 5 mg/kg, while 1 mg/kg or more suppressed hippocampal-kindled seizures. Thus, differences in effective dosages in both amygdaloid- and hippocampal-kindled seizures may suggest a difference in the neuronal mechanisms involved in this kindling.

Accelerated evolution of snake venom phospholipase A2 isozymes for acquisition of diverse physiological functions.

The nucleotide sequences of two cDNAs and four genes encoding Trimeresurus gramineus venom gland phospholipase A2 (PLA2) isozymes were determined and compared internally and externally with those encoding Trimeresurus flavoviridis venom gland PLA2 isozymes. It was revealed that the protein-coding regions are much more diversified than the 5' and 3' untranslated regions (UTRs) and the introns except for the signal peptide domain. The numbers of nucleotide substitutions per site (KN) for the UTRs and the introns were approximately one-quarter of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions and were at the same level as the KN value of T. gramineus and T. flavoviridis TATA box-binding protein (TBP) genes, indicating that the protein-coding regions of PLA2 isozyme genes are unusually variable and that the UTRs including the introns of venom gland PLA2 isozyme genes have evolved at similar rate to those of non-venomous genes. The numbers of nucleotide substitutions per non-synonymous site (KA) values were close to or larger than the KS values for the protein-coding regions in venom gland PLA2 isozyme genes, indicating that the protein-coding regions of snake venom gland PLA2 isozyme genes have evolved via accelerated evolution. Furthermore, the evolutionary trees derived from the combined sequences of the 5' and 3' UTRs and the signal peptide domain of cDNAs were in accord with the consequences from taxonomy. In contrast, the evolutionary trees from the mature protein-coding region sequences of cDNAs and from the amino acid sequences showed random patterns. Estimations of nucleotide divergence of genes and the phylogenetic analysis reveal that snake venom group IJ PLA2 isozyme genes have been evolving under adaptive pressure to acquire new physiological activities.

Retrotransposable CR1-like elements in crotalinae snake genomes.

A part of the 3'-flanking region of BP-II gene, which is one of Trimeresurus flavoviridis venom gland phospholopase A2 (PLA2) isozyme genes, has a region homologous to avian chicken repeat 1 (CR1)-element. In the present study, ten CR1-like elements were further identified in T. gramineus venom gland PLA2 isozyme genes, T. flavoviridis PLA2 inhibitor (PLI) genes, and T. flavoviridis and T. gramineus TATA-box binding protein (TBP) genes. Southern blot analysis using a probe for CR1 showed that Crotalinae snake genomes contain a number of CR1-like elements.

Regional and accelerated molecular evolution in group I snake venom gland phospholipase A2 isozymes.

In accordance with detection of a few phospholipase A2 (PLA2) isozyme genes by Southern blot analysis, only two cDNAs, named NnkPLA-I , and NnkPLA-II, encoding group I PLA2s, NnkPLA-I and NnkPLA-II, respectively, were isolated from the venom gland cDNA library of Elapinae Naja naja kaouthia of Malaysia. NnkPLA-I and NnkPLA-II showed four amino acid substitutions, all of which were brought about by single nucleotide substitution. No existence of clones encoding CM-II and CM-III, PLA2 isozymes which had been isolated from the venom of N. naja kaouthia of Thailand, in Malaysian N. naja kaouthia venom gland cDNA library was verified by dot blot hybridization analysis with particular probes. NnkPLA-I and NnkPLA-II differed from CM-II and CM-III with four and two amino acid substitutions, respectively, suggesting that their molecular evolution is regional. The comparison of NnkPLA-I, NnkPLA-II and cDNAs encoding other group I snake venom gland PLA2s indicated that the 5'- and 3'-untranslated regions are more conserved than the mature protein-coding region and that the number of nucleotide substitutions per nonsynonymous site is almost equal to that per synonymous site in the protein-coding region, suggesting that accelerated evolution has occurred in group I venom gland PLA2s possibly to acquire new physiological functions.

Differences between the tolerance characteristics of two anticonvulsant benzodiazepines in the amygdaloid-kindled rat.

The characteristics of the development of tolerance to the anticonvulsant effects of chronic treatment by dipotassium clorazepate and diazepam using amygdaloid-kindled rats were investigated. Dipotassium clorazepate (5 mg/kg) or diazepam (5 mg/kg) were intraperitoneally administered for 10 consecutive days. Tolerance to the anticonvulsant effect of dipotassium clorazepate developed in seizure stage on day 6, after-discharge duration on day 7 and seizure latency on day 4. In contrast, tolerance to the effects of diazepam developed more rapidly in seizure stage on day 4, after-discharge duration on day 4 and seizure latency on day 3. Thus tolerance to the anticonvulsive effect of dipotassium clorazepate developed relatively slower than that to diazepam. All rats had stage 5 convulsions 24 hr after cessation of the administration of dipotassium clorazepate and diazepam. Concomitant determinations of plasma concentrations of the main metabolite of dipotassium clorazepate and diazepam, desmethyldiazepam, showed no statistical difference during treatment, suggesting that the developed tolerance was not metabolic but functional.

An autopsy case of idiopathic superficial hemosiderosis of the central nervous system: a microscopic and immunohistochemical study.

The brain of a patient with idiopathic superficial hemosiderosis of the central nervous system was examined by light and electron microscopy. A histopathological study revealed massive, symmetrically situated necrosis in the temporal and insular lobes, which has not been described in previous reports. In addition, immunohistochemistry revealed ovoid bodies in the astroglia. Electron microscopy showed that these bodies were composed of fine granules, 50-60 A in diameter, and electron-dense amorphous material. Based on detailed histopathological and ultrastructural findings, the mechanism of ovoid body formation is discussed.

The effect of dinoprost on transport of water and imipramine through rat small intestinal membranes.

The relation between transmucosal fluid movement and its effect on absorption and exsorption of imipramine was studied with the in-situ single-pass perfusion technique in rats. Dinoprost (prostaglandin F2 alpha, PGF2 alpha) caused a dose-related inhibition of both absorption and secretion of water across the intestinal membrane. When PGF2 alpha was infused at a rate of 5 mumols kg-1 h-1, the absorption rate of water decreased from 51.7 to 21.5 mL h-1 and the secretion rate decreased from 48.9 to 26.8 mL h-1. Net water flux changed from net water absorption (0.9 mL h-1) to net water secretion (5.33 mL h-1) by infusion of PGF2 alpha. However, absorption and exsorption of imipramine were little affected by infusion of PGF2 alpha. The absorption rates of imipramine were 3.03 and 2.36 mg h-1 in the absence and presence of PGF2 alpha, respectively. Furthermore, the average amounts of imipramine exsorbed into the intestinal lumen in 2 h were 7.82 and 8.10% in the absence and presence of PGF2 alpha, respectively. Infusion of PGF2 alpha also enhanced motility of the small intestine compared with the control. From these results, it appears that PGF2 alpha has no effect on the absorption and exsorption of imipramine across the intestinal membrane although it is reasonable to use PGF2 alpha in the case of patients with overdoses of drugs which decrease gastrointestinal motility.

Transport of paraquat and mexiletine from the blood into the rat intestinal lumen and peritoneal cavity.

Transport of paraquat and mexiletine from the blood into the intestinal lumen and the peritoneal cavity was examined after their intravenous administration (paraquat: 20 mg kg-1, mexiletine: 10 mg kg-1) to rats. The average amounts of paraquat transferred into the intestinal lumen and the peritoneal cavity were 1.39 and 22.8% of the dose in 120 min, respectively. The average amounts of mexiletine transferred into the intestinal lumen and the peritoneal cavity were 6.1 and 2.5% of the dose in 120 min, respectively. The transfer rate of 3H2O into the peritoneal cavity after intravenous administration (1.85 MBq) was greater than that into the intestinal lumen. In view of the hydrophilic nature of paraquat cation, a solvent drag effect due to movement of water might contribute to transport of paraquat from the blood to the peritoneal cavity. Differences in transport behaviour across the two membranes could be due to differences in the geometrical factors such as the surface area and the distribution of blood vessels. Differences might also be due to differences in physicochemistry and pharmacological effects of both substances.

[Ultrastructural changes in the cerebellum of experimental hypothyroidism (cretinism)].

We examined the cerebellum of the rats being the experimental hypothyroidism (cretinism) on the 20th day, 35th day and 60th day by the light and electron microscope. The remarkable findings were observed to the experimental group on the 20th day. The maturational states of this group correspond to that of the 16th day of the control group. On the other hand, the remarkable pathological findings were not observed on the 35th and 60th day of the experimental group. According to the findings of the experimental rats on the 20th day, the changes of the cells were the retention of the external granule cells and the maturational changes of the internal granule cells. We recognized the retardation of the maturational timing and a disagreement of the maturational rate of the internal granule cells. The lamellar bodies being the disturbance of the mitochondrial cristae were observed. About the white matter, the myelinated nerve fibers were a small quantity in number, and the deficiency of the myelin synthesis, the maturational disturbance of oligoglia were seen. In the several axons, the lamellar bodies and the honeycomb like structures were seen. It is concluded that the maturational disturbance of the internal granule cells are due to the disturbance of the secondary protein synthesis by the hypothyroid state and the degeneration of the mitocondria. The deficiency of the myelin synthesis is related to the maturational disturbance of oligoglia.

[An autopsy case of head injury with a manic-depressive states (author's transl)].

M. M. a man aged 49. He suffered from a head injury at the aged of 41. At that time he lost consciousness for a few minutes and he was diagnosed as a consquassatio cerebri. The sequelaes of his head injury were a change of character and a disturbance of autonomic nerve function. The changes of character were decreased of activity, lie-down for all day, decrease of speech and depressive mode, and occasionally he was ill-humored, restless and irritative. Periodically he became euphoris, talkative and childisch. He had a disturbance of autonomic nerve function which became worse in parallel to the depressive states. We speculated that character changes, such as manic-depressive states and disturbances of autonomic nerve function were due to the bruising of the bilateral orbital surfaces of frontal lobes.

[Olivo-ponto-cerebellar atrophy with personality changes and slight disturbance of intelligence].

H. I., a housewife aged 55 years, began feeling a gait disturbance at 48 years old. After this she had incoordination of arms, dysarthria and tremor of hands. Aged 54 years, she could not stand up by herself. In addition to these neurological signs she had a change of character, such as losing control of herself, unreservedness and unceremoniousness, and slight disturbance of intelligence. She died at the age of 55 years about seven years after the onset. Histopathologically, noticeable changes were observed on the medulla oblongata, pons and cerebellum; the severe neuronal loss of the pontine nuclei and the olivary nuclei with demyelination and gliosis of the cerebellopetal fibers. Especially a great deal of lipofuscin granules in the nerve cells of the frontal and temporal lobe were observed. In the substantia nigra some pigmented cells were deleted. This case was diagnosed as olivo-ponto-cerebellar atrophy clinico-histopathologically. We discussed conserning the etiology of the changes of personality and slight disturbance of intelligence in relation to histopathological changes. It is speculated that the mental disorders are due to the degeneration of the nerve cells in the frontal and temporal lobes.

[Peripheral nerve disease associated with acute renal failure due to bromate poisoning].

A case of 21 year old male with neuropathy caused by renal insufficiency was present. He had taken bromate (mixed powder of potassium bromate and sodium bromate) for the purpose of suicide and suffered from acute renal insufficiency and hard of hearing. Renal dysfunction improved gradually by peritoneal dialysis and hemodialysis. However, on the 32th day after the onset, burning pain appeared in the bilateral feets. Following this, he began to complain of the disturbances of superficial and deep sensory below the ankle jerks and the weakness of his toes. Considering the clinical features, we supposed that the disturbance of the peripheral nerve was caused by uremia due to taking bromate. N. suralis was biopsied on the 80th day after the onset and examined electron microscopically. Electroscopical findings was as follows. Degeneration of the Schwann cells and irregularity or destruction of the myelin sheaths were observed. The axoplasm of the myelinated nerve fiber were relatively preserved as compared with the changes of the myelin sheaths. In the unmyelinated nerve fibers, cavity formations were observed. The findings of regeneration were not observed. From the electron microscopical findings, we speculate that the changes of the Schwann cells and the myelin sheaths are primary resulting from the disturbance of the metabolism of the Schwann cells. We speculate that anemia and hypoproteinemia caused by bromate disturbed regeneration.

[A case of Meige's syndrome associated with post head trauma].

The pathogenesis of Meige's syndrome (MS) is controversial and has yet to be determined up to today. We studied a case of MS associated with post head trauma. The patient was a 52-year-old female. At the age of 46, she began to suffer from oro-lingual dystonia after head trauma induced by a traffic accident and the brief administration of neuroleptics to the delusion deteriorated the dystonia. She showed a wry appearance after 1 year and 6 months of the trauma and began to exhibit blepharospasms, oro-mandibular dystonia and cervical dystonia after 2 years and 3 months. For these symptoms her daily life became difficult. These symptoms were resistant to various drug therapies, although trihexyphenidyl relieved the symptoms transiently. Laboratory examinations and cranial MRI findings were normal. By surface electromyogram of ocular orbicular muscles, bilateral continuous discharge was observed. This patient was diagnosed as MS by clinical symptoms and surface electromyogram findings. It was inferred that the head trauma was associated with the development of MS. We discussed the pathogenesis of MS in the present case and it was speculated that MS was presented by a minute lesion of the brain stem which was produced at the time of the head trauma.

[Histopathological findings of the nerve and muscles in familial primary amyloidosis, with special reference to the mechanism of amyloid fibril production].

T. I., a male aged 38, had a hereditary primary amyloidosis over four generation in his family history. He had peripheral neuropathy with dissociated sensory disturbances in the lower limbs, impotence, gastrointerstial dysfunction and orthostatic hypotention. N. suralis and M. quadriceps femoralis taken from him were examined by light and electron microscopy. N. suralis contained a lot of amyloids reacting with congo-red in the nerve fibres. Amyloid fibrils were remarkably observed around the blood vessels. They were continuous with the basement membrane of the endotherial cells. A few deposites were observed around the Schwann cell and fibroblasts. In M. quadriceps femoralis, amyloid like fibrils were noted in the perivascular spaces. Especially, a great deal of amyloid fibrils were continuous with the basement membranes. From this finding, it might be speculated that the basement membrane may play an important role in the production of amyloid fibrils.