Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus-the 'D-shuttle' project

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter 'D-shuttle' for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the terrestrial background radiation level of other regions/countries.

Incidence of symptomatic autonomic dysreflexia varies according to the bowel and bladder management techniques in patients with spinal cord injury

STUDY DESIGN

A retrospective, multicenter study.

OBJECTIVES

To investigate the relationship between bowel and bladder management methods and symptomatic autonomic dysreflexia (AD) during hospitalization in patients with spinal cord injury (SCI).

SETTING

Twenty-eight Rosai hospitals in Japan.

METHODS

The study subjects were 571 patients with SCI who had been admitted to 28 Rosai hospitals between April 1997 and March 2007 for rehabilitation therapy and fulfilled the following criteria: (1) SCI at or above sixth thoracic level, (2) discharged from hospital after more than 4 months of admission for initial injury and (3) lack of pressure ulcers, deep venous thrombosis, ureteral and renal stones or heterotopic ossification throughout hospitalization to exclude possible influence of these complications on cardiovascular reflexes. The study subjects were examined for the incidence of symptomatic AD according to age, sex, ASIA Impairment Scale, injury level, bowel and bladder management techniques at discharge.

RESULTS

The Rosai Hospital registry included 3006 persons with SCI during 1997-2007, and 571 patients fulfilled the above criteria. The highest incidence of symptomatic AD was diagnosed in subjects using reflex voiding and in those using manual removal of stool. By contrast, the lowest incidence of symptomatic AD was in those on continent spontaneous voiding and continent spontaneous defecation.

CONCLUSION

Medical staff should evaluate the presence of AD in patients with SCI at or above the T6 level under bladder and bowel management such as reflex voiding and manual removal of stool.

Conserved CDR 3 region of T cell receptor BV gene in lymphocytes from bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is an inflammatory lung disease characterized by the accumulation of inflammatory cells and deposition of collagen, resulting in lung remodelling. High numbers of T cells are present in bronchoalveolar lavage fluid (BALF) of IPF patients, although the characteristics of these cells are yet to be determined. To elucidate the pathogenic mechanisms of IPF, we analysed the T cell receptor (TCR) of BALF lymphocytes in three patients with IPF and three healthy subjects as control. TCR repertoire of BALF lymphocytes and T cell clonality were examined by family PCR and Southern blot analysis, and single-strand conformation polymorphism (SSCP), respectively. We observed that the TCR repertoire in the lung was heterogeneous, both in the control subjects and three patients with IPF. SSCP analysis demonstrated an increase in the number of accumulated T cell clones in BALF of two of the three patients, but not in the healthy subject. Furthermore, junctional sequence analysis showed the presence of conserved amino acid motifs (ETGRSG, LAxG, QGQ, GxQP, GRxG, VAR, PGT, GTI, GGT, TGR, LxLxQ, SGQ) in the TCR-CDR 3 region of BAL lymphocytes in patients with IPF, whereas only two amino acid motifs (VTTG, GGE) were found in the control. Our findings suggest that T cells in BALF of patients with IPF expand oligoclonally in the lung, suggesting antigen stimulation of these cells.

Airway epithelial cells promote transmigration of eosinophils in a new three-dimensional chemotaxis model

BACKGROUND

Prominent infiltration of eosinophils in airway mucosa is the pathognomonic sign of asthma. The role of airway epithelial cells in eosinophil infiltration, however, has not been fully elucidated.

OBJECTIVE

The aim of this study is to develop a new in vitro transmigration system composed of airway epithelial cells and extracellular matrix, and to investigate the role of airway epithelial cells in eosinophil infiltration.

METHODS

A layer of type I collagen gel was formed in Netwell, and BEAS-2B bronchial epithelial cells were cultured on the gel. Then the wells covered with epithelial monolayer were filled with medium, inverted, and new upper chambers were constructed on the gel side by applying a ring cap. After further incubation with or without exogenous cytokines for 48 h, eosinophils or neutrophils were loaded in upper chambers (the gel side) and cells transmigrated to lower chambers (the epithelial cell side) were counted. Immunohistochemical analyses were also performed.

RESULTS

While a simple collagen gel hardly promoted eosinophil migration even in the presence of eotaxin or RANTES, significant numbers of eosinophils migrated to lower chambers in the presence of the epithelial cells. Replacement of medium in the lower chamber (the epithelial cell side) with fresh medium, addition of exogenous eotaxin or RANTES in the upper chamber (the gel side), or pre-treatment of eosinophils with anti-CCR3 all inhibited transmigration. We found that the epithelial cells produced and deposited extracellular matrix proteins such as type IV collagen onto the type I collagen gel. Separately, we found that type IV collagen itself was capable of enhancing eotaxin-induced eosinophil migration in a standard chemotaxis assay. Neutrophils also efficiently migrated in the present transmigration system. Pre-treatment of epithelial cells with TNF-alpha and IL-4 enhanced eosinophil transmigration, while that of neutrophils was enhanced by TNF-alpha but suppressed by IL-4.

CONCLUSION

By utilizing a new in vitro transmigration system mimicking the airway mucosa, we have demonstrated that airway epithelial cells play an essential role in transmigration of eosinophils and that multiple factors such as chemokines, extracellular matrix proteins and exogenous inflammatory cytokines are involved in efficient transmigration.

Biochemical and morphological changes in herniated human intervertebral disc

The molecular and morphologic features of herniated human intervertebral disc tissues are of particular importance to clarify the pathogenesis. The present study analyzed the biochemical and morphological features of herniated intervertebral disc tissues to determine the constituent factors responsible for intervertebral disc herniation. A total of 32 herniated disc specimens and 4 control disc samples were analyzed. Collagen subunit composition, collagenase activity, lipid peroxidation level, caspase-3 activity, metal levels, morphologic studies, and genetic analysis were performed on herniated disc tissues of chronic (group A) and acute (group B) group and compared with findings of control group. Nick translation analysis in situ revealed apoptotic-positive stained DNA fragments as black-brown spots in herniated disc tissues. The presence of type II collagen in control disc samples and its absence in herniated samples were confirmed immunohistochemically. The increased caspase-3 activity, the apoptotic-positive stained DNA fragments, and the electron microscopic findings suggest enhanced programmed cell death in herniated discs. The significant increase in lipid peroxidation levels and collagenase activity, and the low metal levels suggest the enhancement of cell death signals in herniated discs, caused by oxygen stress. Linkage analysis of herniated disc tissues in Japanese individuals may suggest ethnic variation. These findings may be helpful in understanding the pathogenesis of herniated disc disease.

Thickening of sphenoid sinus mucosa during the acute stage of pituitary apoplexy

The authors treated two patients with pituitary apoplexy in whom magnetic resonance (MR) images were obtained before and after the episode. Two days after the apoplectic episodes, MR imaging demonstrated marked thickening of the mucosa of the sphenoid sinus that was absent in the previous studies. The relevance of this change in the sphenoid sinus was investigated. Retrospective evaluations were performed using MR images obtained in 14 consecutive patients with classic pituitary apoplexy characterized by acute onset of severe headache. The mucosa of the sphenoid sinus had thickened predominantly in the compartment just beneath the sella turcica, in nine of 11 patients, as ascertained on MR images obtained within 7 days after the onset of apoplectic symptoms. This condition improved spontaneously in all four patients who did not undergo transsphenoidal surgery. The sphenoid sinus mucosa appeared to be normal on MR images obtained from three patients at the chronic stage (> 3 months after onset). The incidence of sphenoid sinus mucosal thickening during the acute stage was significantly higher in the patients with apoplexy than that in the 100 patients without apoplexy. A histological study conducted in four patients who underwent transsphenoidal surgery during the early stage showed that the subepithelial layer of the sphenoid sinus mucous membrane was obviously swollen. The sphenoid sinus mucosa thickens during the acute stage of pituitary apoplexy. This thickening neither indicates infectious sinusitis nor rules out the choice of the transsphenoidal route for surgery.

Complete nucleotide sequence and gene rearrangement of the mitochondrial genome of the Japanese pond frog Rana nigromaculata

In this study, we determined the complete nucleotide sequence of the mitochondrial genome of the Japanese pond frog Rana nigromaculata. The length of the sequence of the frog was 17,804 bp, though this was not absolute due to length variation caused by differing numbers of repetitive units in the control regions of individual frogs. The gene content, base composition, and codon usage of the Japanese pond frog conformed to those of typical vertebrate patterns. However, the comparison of gene organization between three amphibian species (Rana, Xenopus and caecilian) provided evidence that the gene arrangement of Rana differs by four tRNA gene positions from that of Xenopus or caecilian, a common gene arrangement in vertebrates. These gene rearrangements are presumed to have occurred by the tandem duplication of a gene region followed by multiple deletions of redundant genes. It is probable that the rearrangements start and end at tRNA genes involved in the initial production of a tandemly duplicated gene region. Putative secondary structures for the 22 tRNAs and the origin of the L-strand replication (OL) are described. Evolutionary relationships were estimated from the concatenated sequences of the 12 proteins encoded in the H-strand of mtDNA among 37 vertebrate species. A quartet-puzzling tree showed that three amphibian species form a monophyletic clade and that the caecilian is a sister group of the monophyletic Anura.

Analysis of T cell receptor V(beta) gene expression and clonality in bronchoalveolar fluid lymphocytes from a patient with chronic eosinophilic pneumonitis

Chronic eosinophilic pneumonitis (CEP) is characterized by longstanding respiratory symptoms accompanied by a massive pulmonary eosinophil infiltration. T lymphocytes in bronchoalveolar lavage (BAL) from patients with chronic eosinophilic pneumonitis are considered to recognize unknown antigens. To analyze the pathogenesis of CEP, we examined the T cell receptor (TCR) repertoire and T cell clonotype of BAL lymphocytes and peripheral blood lymphocytes (PBLs) in a 66-year-old woman patient with CEP. The expression of TCR BV gene was analyzed by the family PCR method using specific primers for 20 TCR BV genes and BC gene. The clonotype of BAL and peripheral T cells was examined by the PCR-single-strand conformation polymorphism (SSCP) method. Functional sequences of some T cell clones were also carried out. A TCR repertoire of BAL T cells was heterogeneous as well as PBLs. However, SSCP analysis showed that distinct T cell clonotypes were detected in BAL T cells, TCR BV3, BV4, BV6, BV8, BV9, BV14, and BV18-positive T cell clones especially, expanded clonally in BAL from the patient. Sequencing analysis showed that GVD, LGG, RDXS, and SSG amino acid sequence motif were found in the CDR3 in lung-specific T cells. BAL-specific T cell clones accumulated in the patient with CEP. Thus, we can conclude that BAL T cells are induced by the antigen-driven stimulation and these cells might play a crucial role in the generation of CEP.

Concomitant pituitary adenoma and Rathke's cleft cyst

We reviewed the clinical, radiological and surgical findings in patients with both pituitary adenoma and Rathke's cleft cyst. We retrospectively selected patients with both lesions from the 374 patients in whom a sellar/juxtasellar lesion was detected on MRI at 1.5 tesla. All patients received intravenous contrast medium. Concomitant pituitary adenoma and Rathke's cleft cyst were found in eight patients (2.1 %). The frequency of the combination was 3.5 % of pituitary adenomas and 11% of Rathke's cleft cysts. Symptoms were always due to the adenoma, secreting adrenocorticotrophin in two patients and growth hormone in six. The adenoma was larger in five patients, and the cyst in three. The cysts gave variable signal. The adenoma was adjacent to the cyst in seven patients, and enclosed it in the other patient. As a result of experience with MRI, concomitant pituitary adenoma and Rathke's cleft cyst are now known not to be as rare as thought previously. When a non-enhancing cyst-like structure is demonstrated in a patient with pituitary adenoma, the possibility of a coexisting Rathke's cleft cyst should be considered.

[Decompressive craniectomy for massive infarction of middle cerebral artery territory]

There is continuing controversy about the benefits of decompressive craniectomy for the treatment of massive infarction of middle cerebral artery (MCA) territory. Under conservative therapy, the mortality rate for this stroke is reported to be up to 80%. So the authors have actively carried out decompressive craniectomy since 1997, and have compared the outcome with patients who were admitted before 1997 and, consequently treated with conservative therapy. Fifteen consecutive victims of massive infarction of MCA territory were studied. Seven patients (male: 1, female: 6, mean age: 79.8 years) were treated with conservative therapy, and 8 patients (male: 3, female: 5, mean age: 71.8 years) were treated with decompressive craniectomy. There were no significant differences in age and consciousness level distribution between the two groups. Mortality rate in the conservative therapy group was 85.7% against 12.5% in the surgery group (p < 0.05). Functional performance, which was evaluated by activity in daily life (ADL), was also better in the surgery group e.g. 3 patients in ADL 3, and 3 in ADL 4 (1 patient died from a non-neurological cause). Even among the patients with speech-dominant hemispheric stroke, all except one were able to communicate in some way and understand language. Even though patients in this study were elderly, decompressive craniectomy reduced mortality and improved functional performance, so it seems that this surgery should be aggressively considered for massive infarction of MCA territory.

[Long distance air transport by helicopter of a patient with severe head damage]

A report of a case of a patient with severe head trauma with pneumonia and cerebral infarction transported by helicopter. An eighty-year-old male was referred to our hospital because of dyspnea after a fall during sightseeing at Hiroshima. He was lucid at first, but, after two days presented restlessness due to brain contusional hemorrhage and edema. Moreover, he developed pneumonia and cerebral infarction during the period of his hospitalization. He was intubated and received central venous routing. While being transported, his consciousness showed moderate disturbance, aphasia and right hemiplegia. His family asked that therapy be continued near his house in Osaka. We selected transport by helicopter because of his bad general condition and because transport time would be much shorter. He was transported by helicopter to Osaka one month after admission. First, he was transported by ambulance to the airport of Hiroshima. He was carried to the helicopter at the airport. An oxygen cylinder was connected to the incubation tube via an ambu bag because direct connection between the oxygen cylinder and the intubation tube was impossible. Just before the take off, O2 saturation was checked by the pulse oximeter of the ambulance. In the helicopter, there were six men; two pilots, two rescue men, one doctor and the patient. Suction was applied only once and there was no trouble during the flight. The weather was fine and the helicopter experienced almost no rolling during the flight. The flight time was only one hour and twenty minutes. The helicopter safely landed at an emergency heliport in Osaka. The patient was carried to a waiting ambulance and transported to the hospital. Total transport time was only two hours and thirty minutes. This is a case showing a helicopter could safely transport a patient with severe brain damage over a long distance in a short time.

Early rehabilitation effect for traumatic spinal cord injury

OBJECTIVE

To determine the natural course of traumatic spinal cord injury (SCI) and the effect of early rehabilitation on it.

DESIGN

A retrospective, multicenter study.

SETTING

Sixteen Rosai hospitals and 1 medical school.

PARTICIPANTS

One hundred twenty-three SCI patients (104 men, 19 women; mean age, 48.8 +/- 17.7yr) enrolled.

INTERVENTIONS

Dividing the subjects into an early rehabilitation group and a delayed group; differences were ensured by international classification of SCI.

MAIN OUTCOME MEASURES

Using the American Spinal Injury Association (ASIA) classifications, the motor recovery rate (MRR) was defined as (ASIA motor score at discharge - ASIA motor score at admission)/(100 - ASIA motor score at admission). The regression lines for FIM instrument score and ASIA motor score were determined for 6 subgroups (early or delayed tetraplegia, central cord injury, paraplegia) by the MRR staging. The regression lines for physical or cognitive FIM score and ASIA motor score were also determined for 6 subgroups.

RESULTS

Three stages were obtained: acute stage: 2 weeks postinjury; recovery stage: 2 weeks to 6 months postinjury; and chronic stage: more than 6 months postinjury. Regression lines showed that rehabilitation improved physical functional independence for ASIA motor score, especially in the early rehabilitation subgroups. There was no correlation between cognitive FIM score and ASIA motor score in 6 subgroups.

CONCLUSION

Early SCI rehabilitation contributes to good physical activities of daily living for motor function.

Substituted 3-phenylsulfonylquinazoline-2,4-dione derivatives as novel nonpeptide inhibitors of human heart chymase

A series of 3-phenylsulfonylquinazoline-2,4-dione derivatives have been synthesized and evaluated for their ability to inhibit human heart chymase. The structure-activity relationship studies on these compounds gave the following results. The phenyl moiety of quinazoline participates in a hydrophobic interaction where an optimum size is required. In this moiety, 7-chloroquinazoline is the best moiety for inhibiting chymase, chymotrypsin and cathepsin G. A 3-phenylsulfonyl moiety substituted with hydrophobic electron-withdrawing groups at the 4-position potentiated the activity. Anthranil moiety also enhanced the activity. Pyridylmethyl and N-pyridylacetamide at the 1-position gave an IC50 in the order of 10(-8)M. Molecular modeling studies on the interaction of 7-chloro-3-(4-chlorophenylsulfonyl) quinazoline-2,4(1H, 3H)-dione (4) with the active site of human heart chymase suggested that the phenyl moiety of quinazoline interacts with the hydrophobic P1 pocket, the 3-phenylsulfonyl moiety resides in the S1'-S2' subsites, the moiety at the 1-position locates in the S2-S3 subsites and the 4-carbonyl and 3-sulfonyl group interact with the oxyanion hole and the His57 side-chain of chymase, respectively.

Substrate-dependent lipolysis induced by isoproterenol

The relationship between isoproterenol-induced lipolysis and the phosphorylation of perilipin and hormone-sensitive lipase (HSL) was examined using cell-free systems consisting of lipid droplets isolated from rat fat cells and HSL, and/or trioleoylglycerol emulsified with gum arabic and HSL. Isoproterenol was found to stimulate lipolysis in the cell-free system with the lipid droplets without an increase in the phosphorylation of either perilipin or HSL. On the other hand, no stimulation of lipolysis was found in the cell-free system containing lipid droplets despite increases in the phosphorylation of perilipin and HSL. In the cell-free system consisting of trioleoylglycerol emulsified with gum arabic and HSL, neither isoproterenol nor increases in the phosphorylation of perilipin and HSL accelerated lipolysis. These results suggest that isoproterenol-induced lipolysis may not be mediated through the phosphorylation of perilipin and HSL, and may rather be dependent on the substrate of HSL.

Improvement of capillary zone electrophoresis sensitivity with artificial seawater as the background electrolyte utilizing transient isotachophoresis for the determination of nitrate and nitrate ions in seawater

We describe capillary zone electrophoresis (CZE) with transient isotachophoresis (ITP) for the determination of low concentrations of nitrite and nitrate ions in seawater. Bromide-free artificial seawater was adopted as background electrolyte (BGE) to eliminate the interference of high concentrations of salts in seawater. To reverse the electroosmotic flow (EOF), 3 mM cetyltrimethylammonium chloride (CTAC) was added to the BGE. High concentrations of chlorate were added to sample solutions as the terminating ion to generate the ITP process before the CZE separation. In general, the stacking effect increased with increasing amounts of chlorate injected into the capillary. The limits of detection (LODs) for nitrite and nitrate were 0.063 and 0.033 mg/L when the chlorate concentration was 600 and 200 mM, respectively; these were half of those obtained by CZE without the transient ITP. The LODs were obtained at a signal to noise ratio (S/N) of 3. The relative standard deviations (RSD, n = 10) of the peak areas for these ions were 3.2 and 2.9%. The RSDs of peak heights for these ions were 1.6 and 2.1%. The RSDs of migration times for these ions were 0.67 and 0.46%.

Molecular phylogenetic relationships of pond frogs distributed in the Palearctic region inferred from DNA sequences of mitochondrial 12S ribosomal RNA and cytochrome b genes

The evolutionary relationships of pond frogs distributed in the Far East and Europe were investigated by analyses of nucleotide sequences of mitochondrial 12S ribosomal RNA (12S rRNA) and cytochrome b (cyt b) genes. The nucleotide sequences of a 412-bp segment of the 12S rRNA gene and a 534-bp segment of the cyt b gene were determined by the PCR-direct sequencing method using 19 frogs belonging to six species and one subspecies distributed in the Palearctic region. Phylogenetic trees were constructed by the neighbor-joining and maximum-likelihood methods using Rana catesbeiana or Xenopus laevis as an outgroup. The 412-bp segment of the 12S rRNA gene contained 65 variable sites including gap sites, and the 534-bp segment of the cyt b gene contained 160 variable sites. The nucleotide sequence divergences of the 12S rRNA gene were 0.25-4.83% within the Far Eastern frogs, 0.25-6.22% within the European frogs, and 8.74-11.24% between the Far Eastern and the European frogs, whereas those of the cyt b gene were 3.64-14.73% within the Far Eastern frogs, 0.38-14.42% within the European frogs, and 16.53-23.58% between the Far Eastern and the European frogs. Although most nucleotide substitutions were at the third codon position of the cyt b gene and were silent mutations, 4 amino acid replacements occurred within the Far Eastern frogs, 4 within the European frogs, and 11 between the Far Eastern and the European frogs. The phylogenetic trees constructed from the nucleotide sequence divergences showed slightly different topologies for the 12S rRNA and cyt b genes. R. esculenta from Ukraine was closely related to R. lessonae from Luxembourg in both the 12S rRNA and the cyt b gene sequences.

The steady-state kinetics of the enzyme reaction tested by site-directed mutagenesis of hydrophobic residues (Val, Leu, and Cys) in the C-terminal alpha-helix of human adenylate kinase

To elucidate whether the C-terminal region in human adenylate kinase participates in the interaction with the substrate (MgATP(2-) and/or AMP(2-)), hydrophobic residues (Val182, Val186, Cys187, Leu190, and Leu193) were substituted by site-directed mutagenesis and the steady-state kinetics of fifteen mutants were analyzed. A change in the hydrophobic residues in the C-terminal domain affects the affinity for substrates (K(m)), that is, not only for MgATP(2-) but also for AMP(2-), and the catalytic efficiency (k(cat)). The results obtained have led to the following conclusions: (i) Val182 may interact with both MgATP(2-) and AMP(2-) substrates, but to a greater extent with MgATP(2-), and play a role in catalysis. (ii) Val186 appears to play a functional role in catalysis by interacting with both MgATP(2-) and AMP(2-) to nearly the same extent. (iii) Cys187 appears to play a functional role in catalysis. (iv) Leu190 appears to interact with both MgATP(2-) and AMP(2-) substrates but to a greater extent with AMP(2-). (v) Leu193 appears to interact with both MgATP(2-) and AMP(2-) but to a greater extent with AMP(2-). The activity of all mutants decreased due to the change in substrate-affinity. The closer the residue is located to the C-terminal end, the more its mutation affects not only MgATP(2-) but also AMP(2-) substrate binding. The hydrophobic alterations disrupt hydrophobic interactions with substrates and that might destabilize the conformation of the active site. The more C-terminal part of the alpha-helix appears to interact with AMP, as if it has swung out and rotated to cover the adenine moieties. The C-terminal alpha-helix of human adenylate kinase appears to be essential for the interaction with adenine substrates by swinging out during catalysis.

Angiotropic lymphoma: proliferation of B cells in the capillaries of cutaneous angiomas

We report a 52-year-old patient with cutaneous angiomas on the trunk in association with angiotropic lymphoma involving the nervous system. The lesional skin showed proliferation of atypical B cells in the capillaries. The diagnosis of angiotropic lymphoma with neurological deficits is often difficult before death. Thus, skin biopsy in this case proved to be diagnostic of the central nervous system disease without the risk of brain biopsy. The diagnosis of angiotropic lymphoma in the future may be achievable by biopsy of coincidental angiomas.

[A case of idiopathic cranial hypertrophic pachymeningitis presenting Tolosa-Hunt syndrome]

A 48-year-old female was seen because of left orbital pain. The neurological findings were normal at her first visit. She presented temporary double vision during conservative period. Plain CT revealed no mass around the sellar region. Enhanced CT revealed enhanced mass in the left cavernous sinus. MRI revealed low intensity lesion on both T1 and T2 weighted images. Enhanced MRI showed strongly enhanced mass extended from the left cavernous sinus to the dura of sellar floor, the contralateral cavernous sinus, and cerebellar tentorium. Angiography showed stenosis of the left internal cerebral artery. Biopsy from the dura of the tentorium was performed via anterior temporal approach. Abundant collagen fibers with hyalinization were seen in the thickened dura. A final diagnosis of idiopathic cranial hypertrophic pachymeningitis presenting Tolosa-Hunt syndrome was made. Symptoms were free just after the surgery, however, the regrowth of the tentorial lesion was found on MRI after one year. The size of the lesion decreased after administration of steroid.

Sex-linked genes and linkage maps in amphibians

This paper reviews sex-linked genes and linkage maps in amphibians. It appears that there is no common ancestral or conserved sex-linkage group in amphibians, whereas an important proportion of other linkage groups has been conserved in amphibians. Comparisons of amphibian linkage maps with those of fishes and mammals reveal several syntenic associations apparently conserved over a very long period of vertebrate divergence.

Sequence variation and structural conservation in the D-loop region and flanking genes of mitochondrial DNA from Japanese pond frogs

The nucleotide sequences of the D-loop region and its flanking genes of the mitochondrial DNA (mtDNA) from Japanese pond frogs were determined by the methods of PCR, cloning, and sequencing. The frogs belonged to two species, one subspecies, and one local race. The gene arrangements adjacent to the D-loop region were analyzed. The frogs shared a unique mitochondrial gene order that was found in Rana catesbeiana; i.e., cyt b--D-loop region--tRNA(Leu(CUN))--tRNA(Thr)--tRNA(Pro)--tRNA(Phe)--12S rRNA. The arrangements of the three tRNA genes of these frogs were different from those of X. laevis, a species which has the same overall structure as in mammals. Highly repetitive sequences with repeat units (16-bp or 17-bp sequence specific for each taxon) were found in the D-loop region. The length of repetitive sequences varied from 0.6 kbp to 1.2 kbp, and caused the extensive size variation in mtDNA. Several short sequence elements such as putative TAS, OH, CSB-1, and CSB-2 were found in the D-loop region of these frogs. The sequences of these short regulatory elements were conserved in R. catesbeiana, X. laevis, and also in human. The comparison of sequence divergences of the D-loop region and its adjacent genes among various taxa revealed that the rates of nucleotide substitutions depend on genes. The nucleotide sequences of the 3'-side segment of the D-loop region were the most variable among taxa, whereas those of the tRNA and 12S rRNA genes were the most conservative.

cDNA and deduced amino acid sequences of apolipophorin-IIIs from Bombyx mori and Bombyx mandarina

The cDNA sequence for apolipophorin-III from two strains of Bombyx mori (N4 and P50) and the Japanese and Chinese strains of Bombyx mandarina were determined. Both the cDNA and deduced amino acid sequences of the four apolipophorin-IIIs were highly similar (95-98%). The four Bombyx sequences also showed significant similarity to the sequence of apolipophorin-III from another lepidopteran, Manduca sexta (83-84%), particularly in the five amphipathic alpha-helices that are proposed to play a critical role in the binding of apolipophorin-III to lipophorin. In the coding region, the nucleotide sequences for the Chinese strain of B. mandarina and the P50 strain of B. mori were identical, supporting the suggestion that P50 is the current strain most closely related to the original domesticated strain. The N4 strain of B. mori is more closely related to these two strains than is the Japanese strain of B. mandarina, suggesting that Japanese strain of B. mandarina separated from the Chinese strain of B. mandarina before domestication of B. mori. Arch.

Genetic linkage groups in the Japanese brown frog (Rana japonica)

To elucidate the genetic linkage groups of the Japanese brown frog (Rana japonica) and compare them with those of other amphibians, we analyzed the inheritance of alleles at 15 enzyme and blood protein loci and one pigment locus (Blk) in 3,298 offspring derived from 37 crosses using 28 males heterozygous at these loci. Of 63 pairs of loci tested for linkage, 55 pairs showed independent assortment in all crosses examined. In another six pairs, that is, between FUM/ME-1, alpha-GDH/MDH-2, MDH-1/ME-1, MDH-2/ME-2, MDH-2/PEP-C, and ME-2/PEP-C, all the offspring analyzed were parental, and none were recombinant. In the other two pairs, that is, between GPI/PEP-D and AAT-1/Blk, most of the offspring were parental, and some were recombinants with recombination rates ranging from 4.8% to 8.0%. Thus the following four linkage groups comprising 11 loci were established in R. japonica. The first group included the loci for alpha-GDH, MDH-2, ME-2, and PEP-C; the second group included the loci for MDH-1, ME-1, and FUM; the third group included the loci for GPI and PEP-D; and the fourth group included the loci for AAT-1 and Blk. No linkage between the other five loci--ADA, MPI, PEP-A, PGM, and Alb--was observed in the present study.

Dural sinus thrombosis in a patient with protein S deficiency--case report

A 23-year-old female presented with dural sinus thrombosis caused by protein S deficiency. She suffered superior sagittal sinus thrombosis 6 days after delivering her first child. Past history showed deep vein thrombosis at the age of 20. While conservative management was initiated because of the potential risk of increasing intracranial hemorrhage, several hours later she deteriorated rapidly because of severe brain swelling with massive hemorrhage. The patient died despite surgical decompression. Autopsy disclosed organized thrombus in the superior sagittal and transverse sinuses. Although the total concentration of protein S was normal, the free protein S concentration and protein S activity were decreased. Protein S deficiency is a rare cause of dural sinus thrombosis, but is associated with a high mortality rate, so accurate diagnosis and urgent intervention are required.

[A case of hemorrhagic non traumatic arteriovenous fistula of the scalp]

Arteriovenous malformation of the scalp in an uncommon disease and treatment for this lesion is difficult and controversial. A twenty-three-year-old male, who reported no history of head trauma, presented with spontaneous hemorrhage from the left temporal scalp. Neurologically he was normal except the tinnitus. Left external carotid angiography demonstrated arteriovenous malformation fed by the superior temporal and posterior auricular arteries. A dilated tortuous occipital artery was also recognized. The lesions were able to be surgically resected, alleviating intraoperative massive hemorrhage by proximal temporary occlusion of the external carotid artery at the left neck. Small feeding arteries from the meningeal artery which were not recognized on preoperative angiography were found at surgery. The arteriovenous fistula was successfully resected without any cosmetic problem.

The relationship between magnetic resonance imaging findings and clinical manifestations of hypothalamic hamartoma

OBJECT

Hypothalamic hamartoma is generally diagnosed based on its magnetic resonance (MR) imaging characteristics and the patient's clinical symptoms, but the relationship between the neuroradiological findings and clinical presentation has never been fully investigated. In this retrospective study the authors sought to determine this relationship.

METHODS

The authors classified 11 cases of hypothalamic hamartoma into two categories based on the MR findings. Seven cases were the "parahypothalamic type," in which the hamartoma is only attached to the floor of the third ventricle or suspended from the floor by a peduncle. Four cases were the "intrahypothalamic type," in which the hamartoma involved or was enveloped by the hypothalamus and the tumor distorted the third ventricle. Six patients with the parahypothalamic type exhibited precocious puberty, which was controlled by a luteinizing hormone-releasing hormone analog, and one patient was asymptomatic. No seizures or mental retardation were observed in this group. All patients with the intrahypothalamic type had medically intractable seizures, and precocious puberty was seen in one. Severe mental retardation and behavioral disorders including aggressiveness were seen in two patients. The seizures were controlled in only one patient, in whom stereotactically targeted irradiation of the lesion was performed. This topology/symptom relationship was reconfirmed in a review of 61 reported cases of hamartoma, in which the MR findings were clearly described. The parahypothalamic type is generally associated with precocious puberty but is unaccompanied by seizures or developmental delay, whereas the intrahypothalamic type is generally associated with seizures. Two thirds of patients with the latter experience developmental delays, and half also exhibit precocious puberty.

CONCLUSIONS

Classification of hypothalamic hamartomas into these two categories based on MR findings resulted in a clear correlation between symptoms and the subsequent clinical course.

Prevention by methylprednisolone of increased circulating tumor necrosis factor-alpha levels and lung injury associated with systemic inflammatory response syndrome due to intraperitoneal hyperthermia

We previously demonstrated that intraperitoneal hyperthermic perfusion (IPHP), which is performed clinically as a treatment for patients with advanced gastrointestinal cancer, can lead to increased serum tumor necrosis factor-alpha (TNF-alpha), systemic inflammatory response syndrome (SIRS), and acute lung injury. Glucocorticoids inhibit the production and actions of TNF-alpha. We investigated whether pretreatment with methylprednisolone (MPS) may modulate serum TNF-alpha and lung injury in patients subjected to IPHP. Serum TNF-alpha was not detected in the patients pretreated with MPS, whereas serum TNF-alpha increased in the control patients (45.7 +/- 8.3 pg/mL, mean +/- SEM) after IPHP. Postoperative lung injury scores were significantly lower in patients pretreated with MPS than in the control patients (P < 0.001).

IMPLICATIONS

Pretreatment with methylprednisolone attenuates the increase in circulating tumor necrosis factor-alpha and prevents lung injury in this systemic inflammatory syndrome due to intraperitoneal hyperthermic perfusion.

[A case of recurrent-rupture dermoid cyst]

A 58-year-old man was seen because of general convulsions. The neurological findings were normal at his first visit, but CT revealed a low density mass in the right hypothalamus with calcification. T1-weighted image revealed multiple high intensity lesions in the subarachnoid space. Only anti-epileptic drugs were prescribed. He was readmitted one year later because of a traffic accident due to convulsions. CT and MRI revealed other new lesions in the bilateral anterior horn. After four uneventful years, follow-up CT revealed a dilation of the third ventricle. MRI using the fat suppression method showed enhancement around the main tumor and the wall of the lateral ventricles and stenosis of the aqueduct. Right frontotemporal craniotomy was performed. Thickening of the arachnoids and floating lipid droplets were seen in the sub-arachnoid space. A yellowish tumor was found in the suprasellar region, adhering to the internal carotid artery. The tumor contained soft yellowish tissue and hair. Only partial removal was carried out because of severe adhesion to perforators. The lamina terminalis was opened after tumor removal. The postoperative course was uneventful except for transient diabetes insipidus.

High incidence of meningioma among Hiroshima atomic bomb survivors

Since the atomic bomb explosions in Hiroshima and Nagasaki, high incidences of leukemia, thyroid cancer and other tumors have been reported as atomic bomb-induced tumors. We investigated the incidence of meningioma among Hiroshima atomic bomb survivors. Sixty-eight patients surgically treated for meningioma who had been within 2.0 km of the hypocenter of the explosion were identified. Six hundred and seven non-exposed patients with meningioma were also studied. Treatment dates were from 1975 to 1992. The incidences of meningioma among 68 subjects within 2.0 km and 607 non-exposed patients were 8.7 and 3.0 cases per 10(5) persons per year, respectively. The incidences of meningioma among the survivors of Hiroshima in 5-year intervals since 1975 were 5.3, 7.4, 10.1, and 14.9, respectively. The incidences of meningioma classified by distances from the hypocenter of 1.5-2.0 km, 1.0-1.5 km and less than 1.0 km were 6.3, 7.6 and 20.0, respectively. The incidences of meningioma classified by doses to the brain of 0-0.099 Sv, 0.1-0.99 Sv and more than 1.0 Sv were 7.7, 9.2 and 18.2, respectively. The incidence of meningioma among Hiroshima atomic bomb survivors has increased since 1975. There was a significant correlation between the incidence and the dose of radiation to the brain. The present findings strongly suggest that meningioma is one of the tumors induced by atomic bombing in Hiroshima.

Purification, characterization, and application of an acid urease from Arthrobacter mobilis

It has been shown that urea in fermented beverages and foods can serve as a precursor of ethylcarbamate, a potential carcinogen, and acid urease is an effective agent for removing urea in such products. We describe herein the purification and characterization of a novel acid urease from Arthrobacter mobilis SAM 0752 and show its unique application for the removal of urea from fermented beverages using the Japanese rice wine, sake, as an example. The purified acid urease showed an optimum pH for activity at pH 4.2. The enzyme exhibited an apparent K(m) for urea of 3.0 mM and a Vmax of 2370 mumol of urea per mg and min at 37 degrees C and pH 4.2. Gel permeation chromatographic and sodium dodecyl sulfate gel electrophoretic analyses showed that the enzyme has an apparent native molecular weight (M(r)) of 290,000 and consisted of three types of subunit proteins (M(r), 67,000, 16,600, 14,100) denoted by alpha, beta, and gamma. The most probable stoichiometry of the subunits was estimated to be alpha: beta: gamma = 1:1:1, suggesting the enzyme subunit structure of (alpha beta gamma)3. The enzyme also existed as an aggregated form with an M(r) of 580,000. The purified enzyme contained 2 g-atom of nickel per alpha beta gamma unit of the enzyme. Enzyme activity was inhibited by acetohydroxamic acid, HgCl2, and CuCl2. The isoelectric point of the native enzyme was estimated by gel electrofocusing to be 6.8. Urea (50 ppm), which was exogenously added to sake (pH 4.4, 17 +/- 1% (v/v) ethanol), was completely decomposed by incubation with the enzyme (0.09 U ml-1) at 15 degrees C for 13 days. The enzyme was unstable at temperatures higher than 65 degrees C and pHs lower than 4, and was completely inactivated under the conditions of a pasteurization step involved in the traditional sake-making processes. These results indicate that the enzyme is applicable to the elimination of urea in fermented beverages with minimal modification to the conventional process.

Sex-determining mechanism in Buergeria buergeri (Anura, Rhacophoridae). III. Does the ZZW triploid frog become female or male?

Both triploids and gynogenetic diploids (GDs) were produced to clarify the relationship between the sex-chromosome constitution and the expression of sex in the common bell-ring frog, Buergeria buergeri. The sex differentiation of triploids in B. buergeri is quite remarkable. Triploid frogs consisted of three sex genotypes, ZZZ, ZWW and ZZW. All ZZZ triploids were males, and all ZWW triploids were females. It is very interesting that half of the ZZW triploids became female, and the other half became male. The GD frogs consisted of two sex genotypes, ZW and ZZ, which did not differ from the controls in sex differentiation. Since the ratios of ZZ and ZW eggs were significantly different among female parents, it is assumed that most (approximately 80-90%) of the eggs made pre-reductional division in some females and post-reductional division in others during meiosis. It seems that ZW eggs were produced by the occurrence of recombination between the centromere and the sex-determining genes in B. buergeri. It was also found that the number of Z chromosomes in each cell of these triploids and GDs agreed with that of the nucleoli in each cell.

Symptomatic Rathke's cleft cyst coexisting with central diabetes insipidus and hypophysitis: case report

We describe a 48-year-old female with acute onset of central diabetes insipidus followed by mild anterior pituitary dysfunction. Magnetic resonance imaging (MRI) revealed enlargement of the hypophysis-infundibulum accompanied by a cystic component. She underwent a transsphenoidal exploration of the sella turcica. Histological examination showed foreign body type xanthogranulomatous inflammation in the neurohypophysis which might have been caused by rupture of a Rathke's cleft cyst. The MRI abnormalities and anterior pituitary dysfunction improved after a short course of corticosteroid administration, but the diabetes insipidus persisted. The histological findings in this case indicated the site of RCC rupture and the direction of the progression of RCC induced neurohypophysitis and adenohypophysitis.

[Cerebral metastasis from a renal cell carcinoma more than 10 years after nephrectomy: report of two cases]

The authors report two cases with renal cell carcinoma (RCC) metastatic to the brain more than 10 years after nephrectomy. Case 1: An eighty-six-year-old female, on whom nephrectomy had been performed 12 years before, complained of alexia. Computed tomography (CT) revealed ring enhancement in the left temporoparietal region. Total removal of the brain tumor and irradiation of 18 Gy during surgery was performed. Histological examination showed metastatic brain tumor from RCC. The postoperative course was excellent. In the postoperative examination lung metastasis was found. Case 2: A sixty-seven-year-old male, on whom nephrectomy had been performed 15 years before, presented with right hemiparesis, aphasia and convulsion. CT showed two enhanced lesions, one of which accompanied with a hematoma in the left frontal lobe. Chest X-ray showed a coin lesion in the right lower lobe. Total removal of brain tumors was performed and 18 Gy irradiation was administered during surgery. Histological study revealed RCC. However, 3 months after surgery, a new lesion was recognized in the opposite hemisphere. The long interval of latency may be attributed to the slow-growing characteristic of renal cell carcinoma and the fact that renal cell carcinoma is under the influence of host immunity. Surgical treatment is recommended for patients who develop a solitary metastatic lesion or in whom other lesions are controlled and remain in a stable condition.

[A case of non-paralytic pontine exotropia due to brainstem infarction]

A case with non-paralytic pontine exotropia due to brainstem infarction is reported. A 58-year-old male developed sudden onset diplopia. Ocular motor findings were as follows; in forward gaze, the left eye was in abduction position. Leftward gaze, the right eye did not adduct with left beating nystagmus of left eye. Rightward gaze, both eyes could make full excursion and upward, downward gaze were possible. These findings was noted at only acute phase, 7 days later NPPE was disappeared. MRI revealed spotty lesion in the paramedian portion of the mid pontine tegmentum. It is important to observe ocular movement at acute phase because NPPE is very important sign in diagnosis of brainstem disorders.

Site-directed mutagenesis and steady-state kinetic analysis of mutant enzymes of human adenylate kinase

Site-directed mutagenesis of human adenylate kinase (AK) was carried out on residues His36, Lys55, and the C-terminal segment (Val182, V186, and Leu193). Five mutants [(H36T, K55G, V182G, V186S, and L193Stop (deletion of residues 193-194)] were generated and analyzed by steady-state kinetics. H36T, K55G, and L193Stop mutants showed an increase of K(m) values (19.8-, 19.7-, and 11.3-fold) for AMP2- compared to that for the wild-type enzyme, and these residues appeared to interact with AMP2-. V182G showed an increased K(m) value (7.4-fold) for MgATP2-. Therefore, V182 may be essential for interaction with MgATP2-. V186S increased the K(m) value (7.0- and 7.5-fold) for MgATP2- and AMP2-. V186 may thus interact with both substrates. The C-terminal domain of AK appears to be essential for MgATP2- and AMP2- binding.

Demonstration of the optic pathway in sellar/juxtasellar tumours with visual disturbance on MR imaging

OBJECTIVE

To prospectively compare the demonstration of the intracranial optic pathway in patients with sellar/juxtasellar tumours and with clinical evidence of visual disturbance using either spoiled gradient recalled acquisition in steady state (SPGR) or conventional spin echo (CSE) T1-weighted imaging.

MATERIALS AND METHODS

We studied 108 patients with sellar/juxtasellar tumours presenting visual disturbance. Visualization of the optic pathway (nerves, chiasm, tracts) was compared between CSE T1-weighted coronal image and SPGR coronal image. In 18 patients, SPGR imaging was performed before and after administration of Gd-DTPA and visualization of the optic pathway was compared.

RESULTS

On CSE T1-weighted coronal images of 108 patients with visual disturbance, the rates for visualization of the optic nerves, chiasms and tracts were 50%, 77.8% and 89.8% respectively. In contrast, on SPGR coronal image the rates were 80.6%, 96.3% and 92.6% respectively. The rates of visualization of the optic pathway were greater in non-enhanced that in those with enhancement. The rates of visualization in patients with recurrent tumours were less than those in patients with primary tumours. The rate of visualization of optic nerves in patients with meningioma was less than in patients with pituitary adenoma, craniopharyngioma or Rathke cleft cyst.

CONCLUSION

The rate of visualization of optic pathway structures on SPGR imaging (without enhancement) is greater than that on CSE T1-weighted imaging. It is important to understand the accurate position of the optic pathways with using new MR modality especially in surgical planning for lesions around the sella turcica.

Evolutionary relationships among Japanese pond frogs inferred from mitochondrial DNA sequences of cytochrome b and 12S ribosomal RNA genes

The evolutionary relationships among Japanese pond frogs (Rana nigromaculata, R.porosa porosa, and R. p. brevipoda) were investigated by analyzing nucleotide sequences of mitochondrial cytochrome b (cyt b) and 12S rRNA genes. The nucleotide sequences of 444-bp segment of the cyt b gene and 410-bp segment of 12S rRNA gene were determined by the PCR-direct sequencing method using 18 frogs from 13 populations of Japanese pond frogs, and phylogenetic trees were constructed by the neighbor-joining and maximum likelihood methods using R. catesbeiana as an outgroup. The sequenced 444-bp segment of cyt b gene provided 69 variables sites, and the sequenced 410-bp segment of 12S rRNA gene provided 21 variables sites. The numbers of nucleotide substitutions per site of the cyt b gene within ingroup were 0.0022-0.0205 at the populational level, 0.0368-0.0462 at the racial or subspecific level, and 0.1038-0.1244 at the specific level, whereas those of the 12S rRNA gene were 0-0.0074 at the populational or subspecific level, and 0.0378-0.0456 at the specific level. Most nucleotide substitutions within ingroup occurred at the third codon position of the cyt b gene and were silent mutations. High frequencies of transitions relative to transversions were shown at cyt b and 12S rRNA genes within ingroup. The phylogenetic trees constructed from the nucleotide sequences of the cyt b gene showed that after outgroup R. catesbeiana separated from ingroup frogs, ingroup Japanese pond frogs diverged into R.nigromaculata and R.porosa, then the latter diverged into R.p. porosa, R.p. brevipoda (the typical Okayama race), and the Nagoya race of R.p.porosa. The phylogenetic trees constructed from the nucleotide sequences of the 12S rRNA gene also showed distinct divergence between two species, but not any divergence within species.

Alkaline lipase from brain: is it the same enzyme as pancreatic lipase from pancreas?

A new alkaline lipase was detected in rat brain and its properties were compared with those of the well-characterized pancreatic lipase and pancreatic lipase-related protein 2. The activity of the alkaline lipase was determined using trioleoylglycerol emulsion at pH 8.0. Subcellular fractions were prepared from brain homogenates by differential centrifugation. Lipase activities of the cytosolic fraction (the supernatant obtained by differential centrifugation of 100,000g) were stimulated by addition of colipase and bile salts and inhibited by addition of an antibody against rat pancreatic lipase. The partially purified enzyme had an isoelectric point of pH 6.8, which was identical to that found for rat pancreatic lipase. The enzyme had interfacial activation and dependence on colipase in the presence of bile salts. The enzyme had no measurable phospholipase A activity. The band produced by the enzyme on SDS-polyacrylamide gel electrophoresis was identical to that of the rat pancreatic lipase when detected by immunoblotting analysis using an antibody against pancreatic lipase. These results show that pancreatic lipase such as alkaline lipase is in rat brain.

Usefulness of three-dimensional phase contrast MR angiography on arteriovenous malformations

Prospective three-dimensional phase contrast (3D-PC) MR angiography was obtained in 34 patients with arteriovenous malformations (AVM) and comparison was made between digital substraction angiography (DSA) and three-dimensional time-of-flight (3D-TOF) methods. Velocity encoding (VENC) for 3D-PC was adjusted to 60 and 10 cm/sec., and was changed only when adequate information was not obtained. VENC 60 cm/sec, demonstrated the main feeders in 100% of cases and the nidus in 86% of cases whereas VENC 10 cm/sec. showed the draining vein in 78% of cases. The detection rate of feeder, nidus and drainer was 60%, 40% and 13% respectively by the TOF technique. The mean size of the nidus as compared with DSA as standard was 130% with MRI, 108% with 3D-PC and 92% with the TOF technique and this difference was not statistically significant. 3D-PC was clearly superior in detecting AVM in the presence of hemosiderin, hematoma or surgical clips. It also showed gradual disappearance of the lesion after radiosurgery. We found 3D-PC superior to 3D-TOF in the diagnosis, therapeutic planning and follow-up of AVM.

Substituted 3-(phenylsulfonyl)-1-phenylimidazolidine-2,4-dione derivatives as novel nonpeptide inhibitors of human heart chymase

A series of 3-(phenylsulfonyl)-1-phenylimidazolidine-2,4-dione derivatives have been synthesized and evaluated for their ability to selectively inhibit human heart chymase. The structure-activity relationship studies on these compounds gave the following results. The 1-phenyl moiety participates in a hydrophobic interaction where an optimum size is required. At this position, 3,4-dimethylphenyl is the best moiety for inhibiting chymase and showed high selectivity compared with chymotrypsin and cathepsin G. A 3-phenylsulfonyl moiety substituted with hydrogen-bond acceptors such as nitrile and methoxycarbonyl enhances its activity. Molecular-modeling studies on the interaction of 3-[(4-chlorophenyl)sulfonyl]-1-(4-chlorophenyl)-imidazolidine-2,4-dione (29) with the active site of human heart chymase suggested that the 1-phenyl moiety interacts with the hydrophobic P1 pocket, the 3-phenylsulfonyl moiety resides in the S1'-S2' subsites, and the 4-carbonyl of the imidazolidine ring and sulfonyl group interact with the oxyanion hole and the His-45 side chain of chymase, respectively. The complex model is consistent with the structure-activity relationships.

Mitochondrial DNA differentiation in the Japanese brown frog Rana japonica as revealed by restriction endonuclease analysis

To elucidate mtDNA differentiation in the Japanese brown frog Rana japonica, and compare it with results from allozyme analysis and crossing experiments, RFLP analysis was conducted on 78 frogs from 16 populations in Honshu. Purified mtDNA was digested with eight six-base recognizing restriction enzymes and analyzed by 1% agarose-slab gel electrophoresis. Cleavage patterns of the mtDNA showed three distinct genome size classes: small (18.5 kb), middle (20.0 kb) and large (21.5 kb). Ten haplotypes (I approximately X) were observed among the 16 populations. The expected nucleotide divergences within populations ranged from 0 to 0.47% with a mean of 0.08%. The net nucleotide divergences among 16 populations ranged from 0 to 7.74% with a mean of 3.49%. The UPGMA dendrogram and NJ tree, which were constructed based on the net nucleotide divergences, showed that R. japonica diverged first into the eastern and western groups. The eastern group subsequently differentiated into a subgroup containing six populations and the Akita population, and the western group divided into several subgroups. These results, as well as the results of allozyme analysis and crossing experiments, suggest the the eastern and western groups have experienced secondary contact, and introgression has occurred in the Akita population.

Essential lysine residues in the N-terminal and the C-terminal domain of human adenylate kinase interact with adenine nucleotides as found by site-directed random mutagenesis

To elucidate the minimum requirement of amino acid residues for the active center in human adenylate kinase (hAK1), we carried out random site-directed mutagenesis of key lysine residues (K9, K21, K27, K31, K63, K131, and K194), which were conserved in mammalian AK1 species, with the pMEX8-hAK1 plasmid [Ayabe, T., et al. (1996) Biochem. Mol. Biol. Int. 38, 373-381]. Twenty different mutants were obtained and analyzed by steady-state kinetics, and all mutants showed activity loss by Km and/or k(cat) effects on MgATP2-, AMP2-, or both. The results have led to the following conclusions. (1) Lys9 would appear to interact with both MgATP2- and AMP2- but to a larger extent than with AMP2-. (2) Lys21 is likely to play a role in substrate binding of both MgATP2- and AMP2- but more strongly affects MgATP2-. (3) Lys27 and Lys131 would appear to play a functional role in catalysis by interacting strongly with MgATP2-. (4) Lys31 would appear to interact with MgATP2- and AMP2- at the MgATP2- site. (5) Lys63 would be more likely to interact with MgATP2- than with AMP2-. (6) Lys194 in the flanking C-terminal domain would appear to interact not only with MgATP2- but also with AMP2- at the MgATP2- site by stabilizing substrate binding. The loss of the positively charged epsilon-amino group of lysine affects both the affinity for the substrate and the catalytic efficiency. Hence, hydrophilic lysine residues in hAK1 would appear to be essential for substrate-enzyme interaction with the coordination of some arginine residues, reported previously [Kim, H. J., et al. (1990) Biochemistry 29, 1107-1111].