Neuronal stress and injury in C57/BL mice after systemic kainic acid administration

Kainate-induced seizures are widely studied as a model of human temporal lobe epilepsy due to behavioral and pathological similarities. While kainate-induced neuronal injury is well characterized in rats, relatively little data is available on the use of kainate and its consequences in mice. The growing availability of genetically altered mice has focused attention on the need for well characterized mouse seizure models in which the effects of specific genetic manipulations can be examined. We therefore examined the kainate dose-response relationship and the time-course of specific histopathological changes in C57/BL mice, a commonly used founder strain for transgenic technology. Seizures were induced in male C57/BL mice (kainate 10-40 mg/kg i.p.) and animals were sacrificed at various time-points after injection. Seizures were graded using a behavioral scale developed in our laboratory. Neuronal injury was assayed by examining DNA fragmentation using in situ nick translation histochemistry. In parallel experiments, we examined the expression an inducible member of the heat shock protein family, HSP-72, another putative marker of neuronal injury, using a monoclonal antibody. Seizure severity paralleled kainate dosage. At higher doses DNA fragmentation is seen mainly in hippocampus in area CA3, and variably in CA1, thalamus and amygdala within 24 h, is maximal within 72 h, and is largely gone by 7 days after administration of kainate. HSP-72 expression is also highly selective, occurring in limbic structures, and it evolves over a characteristic time-course. HSP-72 is expressed mainly in structures that also manifest DNA fragmentation. Using double-labeling techniques, however, we find essentially no overlap between neurons expressing HSP-72 and DNA fragmentation. These findings indicate that DNA fragmentation and HSP-72 expression are complementary markers of seizure-induced stress and injury, and support the notion that HSP-72 expression is neuroprotective following kainate-induced seizures.

Myelopathy resulting from invasive aspergillosis

Aspergillus, a ubiquitous mold, may cause invasive and fatal disease in immunosuppressed patients. Myelopathy is an uncommon presentation of invasive aspergillosis. This report describes three children admitted to the hospital between 1988 and 1995 who developed myelopathy as the first evidence of invasive aspergillosis. All had advanced leukemia and were profoundly immunosuppressed because of chemotherapy and broad-spectrum antibiotics. Weakness and pain presented first; then, sensation to pain and temperature was lost 2 to 6 days later, followed by complete myelopathy. Multiple brain lesions were seen on magnetic resonance imaging in one patient. Despite antifungal therapy, aspergillosis proved fatal within 1 month of onset of myelopathy in all patients. Physicians caring for immunocompromised children should be aware of myelopathy as a presentation of invasive aspergillosis.

Top DNA polymerase from Thermus thermophilus HB27: gene cloning, sequence determination, and physicochemical properties

A gene, top encoding Thermus thermophilus HB27 (Top) DNA polymerase, was cloned in E. coli and its nucleotide sequence was determined. Based on its deduced amino acid sequence, Top DNA polymerase is a 93.8 kDa protein comprising 834 amino acid residues. Top DNA polymerase showed high amino acid homology with those of other DNA polymerases from the Thermus sp., for example, 87.3% identity with Taq DNA polymerase. Codon usage in the top gene was similar to those of the proteins from other Thermus strains. The G + C content in the third position of the codons was as high as 93%. The top gene under the control of the tac promoter was expressed in E. coli [plasmid pTOP9]. DNA amplification using the recombinant Top DNA polymerase performed the same as other thermostable DNA polymerases from Thermus strains. The optimum temperature for its reaction was 76 degrees C. An interesting observation was that the recombinant Top DNA polymerase was slowly cleaved into two fragments of about 60 kDa and 35 kDa at 4 degrees C and -20 degrees C. The larger fragment possessed polymerase activity like the Klenow fragment of E. coli DNA polymerase I. To prevent the cleavage of the Top DNA polymerase, a variety of protecting agents were examined. Among those examined, (NH4)2SO4 (100 mM) solution demonstrated an outstanding ability to block its cleavage for a prolonged period.

Protein C and S deficiency in children with ischemic cerebrovascular accident

A prothrombotic state caused by a deficiency of protein C or protein S, each an inhibitor of coagulation cascade, increases the risk of ischemic cerebrovascular accident (ICVA) in young adults. This retrospective review studies the relationship of protein C or S deficiency with childhood ICVA. From 1989 to 1995, 37 children were diagnosed by neuroimaging with ICVA unrelated to any known preexisting diagnosis. Protein C deficiency or protein S deficiency was the only identified risk factor for 5.4% (2 patients) and 13.5% (5 patients), respectively, of these 37 children. The data suggest that protein C or protein S deficiency is an important risk factor of ICVA in children.

Antisense expression of the peptide transport gene AtPTR2-B delays flowering and arrests seed development in transgenic Arabidopsis plants

Previously, we identified a peptide transport gene, AtPTR2-B, from Arabidopsis thaliana that was constitutively expressed in all plant organs, suggesting an important physiological role in plant growth and development. To evaluate the function of this transporter, transgenic Arabidopsis plants were constructed expressing antisense or sense AtPTR2-B. Genomic Southern analysis indicated that four independent antisense and three independent sense AtPTR2-B transgenic lines were obtained, which was confirmed by analysis of the segregation of the kanamycin resistance gene carried on the T-DNA. RNA blot data showed that the endogenous AtPTR2-B mRNA levels were significantly reduced in transgenic leaves and flowers, but not in transgenic roots. Consistent with this reduction in endogenous AtPTR2-B mRNA levels, all four antisense lines and one sense line exhibited significant phenotypic changes, including late flowering and arrested seed development. These phenotypic changes could be explained by a defect in nitrogen nutrition due to the reduced peptide transport activity conferred by AtPTR2-B. These results suggest that AtPTR2-B may play a general role in plant nutrition. The AtPTR2-B gene was mapped to chromosome 2, which is closely linked to the restriction fragment length polymorphism marker m246.

Cerebellar mutism in children: report of six cases and potential mechanisms

Cerebellar mutism is a rare finding associated with resection of posterior fossa tumors or cerebellar hemorrhages. We reviewed the medical records of six children, aged 6 to 12 years, who developed cerebellar mutism after resection of a posterior fossa mass or as a result of posterior fossa trauma. From 1989 to 1994, 210 children underwent posterior fossa resection at our institution, and four developed mutism (an incidence of 1.6%). All four patients had primitive neuroectodermal tumors. The fifth patient experienced trauma, and another patient had an arteriovenous malformation (AVM). In four children, hydrocephalus developed as a result of their tumor or AVM. Four developed cerebellar mutism 24 to 48 hours after surgery or trauma, and one developed cerebellar mutism 5 days after surgery, coincident with hydrocephalus. In one, mutism occurred after a second resection was performed for a recurrence of his posterior fossa tumor. Cerebellar mutism lasted 10 days in one patient and 2 to 8 weeks in the other four. Dysarthria was apparent in four patients during the recovery phase. We suggest trauma to the dentate nucleus and/or its outflow tract, the superior cerebellar peduncle, as a cause of reversible mutism. Because posterior fossa tumors are common in children, mutism should be recognized as an important side effect of surgery.

The resolution of the dative NP ambiguity in Korean

An eye-movement study examined the ambiguity of the dative noun phrase (NP) in Korean, which may be attached either to the main verb or to a relative verb. Experimental sentences of the form NP-Nom NP-Dat NP-Nom V (dative) NP-Acc V (dative or simple transitive; Nom = nominative; Dat = dative; V = verb; Acc = accusative) were tested. Garden-path theory predicts that comprehension difficulty occurs when the main verb is transitive, forcing the dative NP to be attached to the relative verb, because the dative NP will have already been attached in the clause posited when the first nominative NP is read. In contrast, lexically based theory predicts that comprehension difficulty occurs when the main verb is a dative verb, because the dative NP will be attached to the first verb encountered (the relative verb). The present study did not fully support either theory, because the differences seen in the experimental conditions appeared, at least in part, in the control conditions. However, the results were much different from the prediction of lexically based theory. Reading was faster, and regressive eye movements fewer, in the dative-ambiguous condition than in the transitive-ambiguous condition. Some reasons for the unexpected difficulty of the transitive-unambiguous condition are advanced.

Cloning and expression of the gene for xylose isomerase from Thermus flavus AT62 in Escherichia coli

The gene encoding xylose isomerase (xylA) was cloned from Thermus flavus AT62 and the DNA sequence was determined. The xylA gene encodes the enzyme xylose isomerase (XI or xylA) consisting of 387 amino acids (calculated Mr of 44,941). Also, there was a partial xylulose kinase gene that was 4 bp overlapped in the end of XI gene. The XI gene was stably expressed in E. coli under the control of tac promoter. XI produced in E. coli was simply purified by heat treatment at 90 degrees C for 10 min and column chromatography of DEAE-Sephacel. The Mr of the purified enzyme was estimated to be 45 kDa on SDS-polyacrylamide gel electrophoresis. However, Mr of the cloned XI was 185 kDa on native condition, indicating that the XI consists of homomeric tetramer. The enzyme has an optimum temperature at 90 degrees C. Thermostability tests revealed that half life at 85 degrees C was 2 mo and 2 h at 95 degrees C. The optimum pH is around 7.0, close to where by-product formation is minimal. The isomerization yield of the cloned XI was about 55% from glucose, indicating that the yield is higher than those of reported enzymes. The K(m) values for various sugar substrates were calculated as 106 mM for glucose. Divalent cations such as Mn2+, Co2+, and Mg2+ are required for the enzyme activity and 100 mM EDTA completely inhibited the enzyme activity.

Contagious ecthyma in the live sheep export industry

OBJECTIVE

To investigate control options for contagious ecthyma (scabby mouth) in Australian sheep exported live to the Middle East.

DESIGN

Prevalence, vaccination and modelling studies.

PROCEDURE

One hundred and forty weaner sheep (less than 1 year old) on each of 106 farms in Western Australia (WA) and 18 farm groups of adult wethers received at a WA commercial feedlot were examined for lesions of scabby mouth. Sheep on a total of 26 farms in 3 States were divided into treatment and control groups for the vaccination study. A simple deterministic compartmental model was developed to establish which parameters had the greater effect on disease prevalence.

RESULTS

The proportion of farms with evidence of scabby mouth in weaner sheep was 23.6% and, on those farms with the disease, the overall prevalence was 6.1%. At the feedlot, 4 out of 18 farm groups had 5 or more sheep with lesions on arrival. The overall prevalence in the 4 diseased groups was 5.2%. Sheep vaccinated on farm before trucking to the feedlot had a lower prevalence of scabby mouth at the end of simulated shipping than controls. The main determinant of scabby mouth prevalence was the proportion of sheep immune to the disease.

CONCLUSION

A program of vaccination for scabby mouth will reduce the prevalence of disease during live export. However, using current technology it is not possible to deliver shipments of sheep to the Middle East that are guaranteed completely free of scabby mouth.

Preventing factitious gingival injury in an autistic patient

A 34-year-old man with a history of autism developed a deep gingival cleft. During clinical evaluation, the patient repeatedly scraped the affected area with his fingernail. The lesion's clinical features were consistent with focal inflammatory hyperplasia, periodontal disease and factitious stomatitis. This article describes the case and discusses diagnostic and behavioral issues important in treating any patient whose mental age is impaired.

[Development and progression of pyogenic spondylitis in a canine experimental model]

An experimental model was prepared to investigate the process of inflammation in pyogenic spondylitis. Forty-seven mongrel dogs were used, involving 24 mature and 23 immature dogs. Under intravenous pentobarbital anaesthesia, the lumbar vertebral bodies were approached posterolaterally and inoculated using a small piece of gauze soaked in a staphylococcus aureus suspension. Roentgenographic and histological examinations were regularly performed for 24 weeks after the inoculation. Histologically, acute inflammation started within 1 or 2 weeks, and subsided by 5 or 6 weeks in both the mature and immature dogs. In 55% of the dogs, the inflammation was confined within the vertebral body, in 10% it invaded into the intervertebral disc, and in 35% inflammation invaded into the anterior longitudinal ligament. In the immature dogs, thickening of the trabeculae and the anterior cortex was observed around the inflammatory focus more often than in the mature dogs. The epiphyseal line acted as a barrier against invasion by the inflammation in the immature dogs. However, direct invasion of the inflammatory process into the disc could have occurred through the vascular buds which were the terminal branches of the metaphyseal artery close to the disc in both the mature and immature dogs. In contrast to the results reported by Ohno who inoculated the lumbar discs of mongrel dogs with staphylococcus aureus, in the present study, the disc space remained intact and was replaced by fibrous tissue. Consequently, it was concluded that pyogenic spondylitis should be defined as a different clinical entity from discitis.

[The detection of anti-cerebellar antibody western blot analysis in serum from a patient with Miller Fisher syndrome]

We here report a case of Miller Fisher syndrome (MFS) in which serum anti-cerebellar antibody was detected by Western blot analysis. The 32-year-old male studied suffered from diplopia, gait ataxia and sensory disturbance in the distal portion of the upper limbs preceded by cold-like symptoms. Neurological examination on admission revealed that he had external ophthalmoplegia with bilateral ptosis, cerebellar ataxia and areflexia. A cerebrospinal fluid examination showed albuminocytologic dissociation with a protein concentration of 60 mg/dl. Brain CT and MRI showed no significant abnormalities. The patient was diagnosed as MFS, and treated it with two sessions of immunoadsorption plasmapheresis (IAPP). After receiving IAPP therapy, the patient's neurological symptoms and signs were improved. Western blot analysis showed the existence of antibody directed against mouse cerebellum but not against mouse cerebrum, brain stem, and spinal cord in his serum, the level of which was decreased after the IAPP therapy. Serum anti-GQ1b antibody was also elevated. As far as we are aware, there have been no reports showing the existence of anti-cerebellar antibodies detected by Western blot analysis. Though the pathogenesis of MFS remains unclear, our findings suggest that anti-cerebellar antibody detected by Western blot analysis may be caused by cerebellar ataxia in MFS.

Metal affinity engineering of proinsulin carrying genetically attached (His)10-X-Met affinity tail and removal of the tag by cyanogen bromide

An E. coli expression clone coding for human proinsulin, which was fused to NH2-terminal beta-galactosidase, was engineered for the separation from host proteins by introducing peptide devices, and for the sequential removal of the fused polypeptide by cyanogen bromide in front of the NH2 terminal residue (methionine) of the human proinsulin gene. Short synthetic genes encoding oligopeptide residues including (Glu)n, (His)n, (Trp)n, and (Ser)n (n = 10 or 11), which have certain characteristic physical properties such as metal-affinity, polarity, hydrophobicity, and hydrophilicity, respectively, were inserted at the junction region of the gene fusion. Interestingly, it was found that among the oligopeptides, the oligohistidine residue as an affinity-tag has greatly facilitated the procedures for FPI purification, particularly in the manner of selective metal-affinity precipitation. The chelating peptide covering the NH2-terminal beta-galactosidase portion could then be removed simply after purification to generate a protein with the natural amino acid sequence of proinsulin by cyanogen bromide.

Immunoelectron microscopic localization of the HPC-1 antigen in rat cerebellum

HPC-1 antigen is a neuron-specific 34 kDa protein, identical to p35A (syntaxin), and is thought to play important roles in docking or fusion of synaptic vesicles to presynaptic active zones. In the present study we analyze the distribution of HPC-1 antigen in rat cerebellum by a cryoimmunogold technique using an antibody against the fusion protein of beta-galactosidase and the HPC-1 antigen. HPC-1 antigen was detected at high density on the plasma membranes and synaptic vesicles of presynaptic boutons which formed synapses with dendrites of Purkinje cells, and on the plasma membranes of parallel fibres in the cerebellar molecular layer. In the granule cell layer, gold particles were also detected on the endoplasmic reticulum, nuclear membranes and the plasma membranes of granule cells. Presynaptic membranes and synaptic vesicles in glomeruli were also labelled by gold particles. To determine the topology of HPC-1 antigen on the membranes, the synaptosome fraction prepared from rat cerebellum was embedded in agarose, and processed for the pre-embedding protein A-gold technique. Intact synaptosomes were not labelled by gold particles. However, when fixed in hypotonic fixative to rupture plasma membranes, or when ruptured after fixation in normotonic fixative, the cytoplasmic surfaces of presynaptic membranes and synaptic vesicles were labelled by gold particles. These results suggest that most of the epitopes of HPC-1 antigen are located on the cytoplasmic surface of plasma membranes and synaptic vesicle membranes.

[Surgical treatment of metastatic lung tumors]

From January 1970 to March 1991, 72 operations in 55 patients (31 males and 24 females) with metastatic lung tumors were performed in our department. Their cumulative survival rates was 25.5% at five years. With analysis of the various prognostic factors, patients both with solitary metastases and without lymph node metastases had a good prognoses. However, even in patients with recurrent lung metastatic tumors, long time survival was achieved with reoperation in two patients. We concluded that reoperation with or without effective chemotherapies was effective in selected patients.

[Changes of plombage-operations in respiratory surgery]

The first plombage-operation for pulmonary tuberculosis was by Dr. Nagaishi (1947) and Dr. Wilson, who developed the plombage method employing hollow polymethylmethacrylate spheres. Although the method presented a relatively effective option at a time when no effective drugs were available, its use was discontinued because of such complications as lung injury, cavity-perforation, and empyema. Therefore, soft elastic resin materials, such as those used in sponge-plombage and air-plombage, replaced the hard resin materials. Each plombage method is associated with a certain medical historical period, in Japan. Still the "Kinchyu" method was used. However, the complication of chronic empyema with bronchopleural fistula was difficult to treat. A notable recent method is the pedicled omentum plombage method, which is effective in the treatment of patients who have not responded to standard operations. Finally there was surely a clinical significance in each medical historical period.

Immunoblot analysis of IgE and IgG antibodies to honey bee venom: cross sectional and sequential studies in bee sensitive subjects

To investigate the specific IgE and IgG immune response to honey bee venom (bv), we performed immunoblot analysis of sera from 47 bee sensitive subjects and followed the response during and after venom immunotherapy in 15 of these subjects. Fifteen venom proteins varying in molecular size from 20 to 105 kDa were identified as being antigenic and consisted of a high molecular weight (HMW) group (5 to 105 kDa, containing the previously identified allergens B and C) and a low molecular weight group (LMW) containing hyaluronidase and phospholipase A. In general for a given individual the anti-venom IgE and IgG response was qualitatively similar although some variation between individuals was apparent. Reactivity with hyaluronidase and phospholipase A appeared only in those subjects showing reactivity with HMW components. During immunotherapy specific anti-venom IgG and IgE responses tended to be linked. Increased responses being seen against all components in 4 of 12 subjects, reductions in 3 and unchanged responses in the remainder. Following immunotherapy (mean 4.0 years), spontaneous reduction of IgE and IgG was seen in 5 of 5 subjects. Loss of reactivity with the LMW components was prominent in these sera.

Differential regulation of the low-affinity nerve growth factor receptor during postnatal development of the rat brain

We studied the temporal and spatial localization of the low-affinity nerve growth factor receptor (LNGF-R) during the early postnatal period in rat brain in order to understand better the relationship between nerve growth factor (NGF)-like responsiveness and the development of specific central neuronal populations. Four different developmental patterns of LNGF-R mRNA hybridization were found in this study. First, some neurons contain high levels of LNGF-R mRNA from postnatal time points into adulthood, as exemplified by neurons of the cholinergic basal forebrain and mesencephalic trigeminal nucleus. Second, several cell groups exhibit robust hybridization during the early postnatal period but contain much reduced levels of LNGF-R mRNA in the adult brain. These include striatal neurons, Purkinje cells of the cerebellum, and several medullary nuclei. A third group of cells produces the LNGF-R transiently during development, including cranial nerve nuclei of the brainstem, the periolivary nuclei complex, the reticular formation, and the deep cerebellar nuclei. Finally, cell populations which may exist only transiently during central nervous system (CNS) development, such as subplate neurons of the cerebral cortex, appear to express the LNGF-R during only a brief period. These results show that the LNGF-R gene is differentially regulated in a cell type-specific manner during development, and suggests that diverse neuronal populations require only transient growth factor sensitivity, while others exhibit NGF-like responsitivity into maturity.

Application of a metal capillary column in gas chromatographic determination of catechol-o-methyltransferase activity

The utility of a deactivated metal capillary column, Rascot, in the measurement of an enzymatic reaction, in this case measurement of rat catechol-O-methyltransferase activity, was examined. 3,4-Dihydroxybenzaldehyde, 3,4-dihydroxybenzylalcohol and 3,4-dihydroxybenzoic acid were used as substrates and the m- and p-O-methylated products were separated by using Rascot after derivatization. The peaks on the chromatograms were symmetrical. The data obtained were compared with those reported in previously published papers. Good agreement with previous results proved that Rascot is able to withstand practical use in biological materials.

Histological changes in aging lumbar intervertebral discs. Their role in protrusions and prolapses

To study the relationships between the changes due to aging in lumbar intervertebral discs and the development of protrusion or prolapse, we carried out histological studies on operative specimens of thirty-one discs, of which twenty-two had been protruded and nine, prolapsed. The specimens were obtained during twenty-nine operations for herniation of a lumbar intervertebral disc in patients who were sixty years old or older. Changes in the anulus fibrosus were more extensive in the nine prolapsed discs than in the twenty-two protruded discs. Of the nine prolapsed discs, myxomatous degeneration, fibrosis, and swollen anular fibers were found in all nine, and cysts were seen in five. Of the twenty-two protruded discs, only five showed myxomatous degeneration; ten, fibrosis; one, a cyst; and sixteen, swollen fibers. For comparison, we also studied specimens that had been obtained at operation from twenty-one other patients, twenty to fifty-nine years old, who had a prolapsed disc. The anulus showed myxomatous degeneration in all twenty-one specimens, cysts in eight, and fibrosis in ten. In addition, we examined 368 autopsy specimens from people who had been between twenty-five and eighty-five years old at the time of death. In many of the subjects who had died in the sixth decade of life or later, we found that the orientation of the inner fiber bundles of the anulus fibrosus was reversed, so that they bulged inward. The reversal appeared to be the result of myxomatous degeneration of the middle fibers of the anulus, atrophy of the nucleus, and narrowing of the disc space. These histological findings suggest explanations for the predominance of protrusions of the nucleus pulposus in patients who are less than sixty years old and of prolapse of the anulus fibrosus in the few patients who are more than sixty years old who have herniation of an intervertebral disc.