Direct observation of hydrogen-bond exchange within a single water dimer

The dynamics of water dimers was investigated at the single-molecule level by using a scanning tunneling microscope. The two molecules in a water dimer, bound on a Cu(110) surface at 6 K, were observed to exchange their roles as hydrogen-bond donor and acceptor via hydrogen-bond rearrangement. The interchange rate is approximately 60 times higher for (H2O)2 than for (D2O)2, suggesting that quantum tunneling is involved in the process. The interchange rate is enhanced upon excitation of the intermolecular mode that correlates with the reaction coordinate.

Short-term plasticity of central benzodiazepine receptors in status epilepticus: case report

(123)I-iomazenil SPECT is of value in determining an epileptogenic focus, however, transient uptake change has been rarely reported in epileptic disorders. A 78-year-old woman diagnosed as status epilepticus (SE) showed transient reduction in (123)I-iomazenil uptake within the epileptic foci on SPECT images during a couple of weeks. It suggests a seizure-related 'short-term' plasticity in the central benzodiazepine receptors and dynamic change in the regulatory mechanisms of inhibitory neurotransmitter system within the epileptic foci in patients with SE.

Selective expansion of the CD14(+)/CD16(bright) subpopulation of circulating monocytes in patients with hemophagocytic syndrome

Overproduction of proinflammatory cytokines is characteristic of hemophagocytic syndrome (HPS), a highly lethal inflammatory disease. Peripheral blood monocytes include two distinct subpopulations according to surface antigen expression: a major type, CD14(+)/CD16(-) (classical monocytes), and a minor type, CD14(+)/CD16(bright) (proinflammatory monocytes). Among peripheral blood monocytes from HPS patients, CD14(+)/CD16(bright) cells were increased, together with lipopolysaccharide-induced production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6. By three-color immunofluorescence, CD14(+)/CD16(bright) monocytes exhibited more intense human leukocytic antigen DR than CD14(+)/CD16(-) monocytes, consistent with greater maturity. Serum IL-6, TNF-alpha, and IL-8 were increased in HPS patients. A sensitive inflammatory marker, neutrophil CD64 expression, also was significantly elevated in HPS patients. In conclusion, expansion of proinflammatory monocytes and increased expression of neutrophil CD64 appeared to be important in the pathophysiology of HPS. Expansion of CD14(+)/CD16(bright) monocytes and neutrophil CD64 expression could serve as indicators of the inflammatory state in HPS.

Steplike lattice deformation of single crystalline (La0.4Pr0.6)1.2Sr1.8Mn2O7 bilayered manganite

We report a steplike lattice transformation of single crystalline (La0.4Pr0.6)1.2Sr1.8Mn2O7 bilayered manganite accompanied by both magnetization and magnetoresistive jumps, and examine the ultrasharp nature of the field-induced first-order transition from a paramagnetic insulator to a ferromagnetic metal phase accompanied by a huge decrease in resistance. Our findings support that the abrupt magnetostriction is closely related to an orbital frustration existing in the inhomogeneous paramagnetic insulating phase rather than a martensitic scenario between competing two phases.

Adsorbed states and scanning tunneling microscopy induced migration of acetylene on Cu(110)

The authors have studied adsorption of acetylene on Cu(110) by means of low-temperature scanning tunneling microscopy. Adsorbed molecules preferentially aggregate at 40 K to yield dimer, trimer, and larger islands on the surface. Isolated species (monomer) adsorbs on the fourfold hollow site with approximately sp3 rehybridization as characterized by inelastic electron tunneling spectroscopy. Tunneling electron induces an acetylene molecule to migrate along the trough of Cu(110). The migration proceeds in two steps: the molecule first hops to the adjacent long-bridge site and then to the next fourfold site. The voltage and current dependencies of the hopping probability show that the migration is induced by inelastic electron tunneling that causes vibrational excitation of mainly C-H stretch mode.

Psychiatric, somatic, and gastrointestinal disorders, and Helicobacter pylori infection in children with recurrent abdominal pain

AIMS

To examine the utility of the Rome II criteria in children with recurrent abdominal pain (RAP) and compare them to those who met Apley's criteria and those who met neither criteria.

METHODS

Prospective study in general paediatric clinics in Komagane, Japan. Children with abdominal pain were classified into those who met Rome II criteria, those who met Apley's criteria, and those who met neither.

RESULTS

A total of 182 children with RAP participated; 45 children met Rome II criteria, 55 met Apley's criteria, and 82 met neither. Children who met Rome II criteria had a significantly higher prevalence of psychiatric and somatic disorders compared to the group met neither (36% v 6%, 22% v 10%, respectively). The overall prevalence of H pylori was 7%; prevalence increased with age from 3% at age < or = 10 to 10% for children >10 years. Children who met Rome II criteria had a significantly higher prevalence of H pylori infection than the reference group (18% v 4%). In a logistic regression model, all the study variables were included in the model specifying first the Rome II criteria group as the independent variable; psychiatric disorders, H pylori infection, and older age group were independent risk factors.

CONCLUSIONS

More than half the children suffering from recurrent abdominal pain met neither Apley's nor Rome II criteria. Children who meet Rome II criteria should be evaluated for psychiatric disorders and should be tested for H pylori infection. Despite the overall trend for a fall in the prevalence of H pylori infection among children in Japan, there are subpopulations of sick children where the prevalence of the infection is relatively high.

Altered alpha1-syntrophin expression in myofibers with Duchenne and Fukuyama muscular dystrophies

Alpha1-syntrophin, a scaffolding adapter and modular protein, is a cytoplasmic component of the dystrophin glycoprotein complex. This study investigated immunohistochemically the expression of alpha1-syntrophin in Duchenne and Fukuyama muscular dystrophies (DMD and FCMD, respectively). Biopsied muscles of five DMD, five FCMD, five normal controls and five disease controls (three myotonic and two facioscapulohumeral dystrophies) were analyzed. Immunoblot analysis showed that anti-alpha1-syntrophin antibody had a decreased reaction in both DMD and FCMD muscle extracts. Biopsied muscle sections and their serial sections were immunostained with rabbit anti-alpha1-syntrophin and rabbit anti-muscle-specific beta-spectrin antibodies, respectively. Immunoreactive patterns of sarcolemma were classified into (i) a continuously positive immunostaining pattern, (ii) a partially positive immunostaining pattern, (iii) a negative immunostaining pattern and (iv) a faint but entire surface positive immunostaining pattern. The group mean percentages of alpha1-syntrophin and beta-spectrin immunonegative myofibers in the DMD group were 39.3% and 10.8%, respectively, while those in the FCMD group were 45.5% and 10.4%, respectively. These values were statistically significant compared with those of disease control and normal control muscles. Thus we found that dystrophin-deficient DMD muscles contained significant numbers of alpha1-syntrophin-positive fibers and significant numbers of alpha1-syntrophin-negative fibers were present in dystrophin-positive muscles of severe muscular dystrophy such as FCMD. Alpha-dystrobrevin immunoreactivity was tested in DMD muscles and appreciable amounts of alpha-dystrobrevin that binds to syntrophin were found in DMD muscle membranes.

A sero-epidemiological survey of gelatin sensitization in young Japanese children during the 1979-1996 period

Recently, an increasing number of adverse reactions in children inoculated with live attenuated virus vaccines containing gelatin have been reported. However, the distribution, magnitude and rate of gelatin sensitization in the Japanese population have not been established. Here, the purpose was to investigate the distribution of children with positive gelatin immunoglobulin G (IgG) and/or IgE in Japan and to ascertain whether the incidence of positive antigelatin antibody cases among the general population, as reflected in the sample employed here, has been increasing during the period in question. The presence of IgE and IgG antibodies were measured against gelatin in 1600 panel sera collected from different age groups of Japanese children in Hokkaido/Sapporo from 1979 through 1996. Among the subjects, 39 had gelatin IgG- and/or IgE-positive sera, and these were correlated with the time of obtaining the sera as well as with the age of the subjects. The older the subject and the later the period, the higher the sero-incidence. Japanese children have become increasingly sensitized to gelatin, especially since the mid-1990s.

Human Kluver-Bucy syndrome following acute subdural haematoma

We present a rare case of complete human Kluver-Bucy syndrome (KBS) following recovery from transtentorial herniation caused by acute subdural haematoma (ASDH). A 17-year-old right-handed high school boy got into stupor within five minutes after 3-rounds of sparing at boxing. Emergency computed tomographic (CT) scan showed right cerebral hemispheric ASDH, which was evacuated following intentional decompressive craniectomy. After recovery of consciousness, he developed emotional changes (placidity with loss of normal fear and anger), psychic blindness, aberrant sexual behaviour, excessive oral tendencies, increased appetite, and hypermetamorphosis in order of mention, which were observed with waxing and waning from 17th to 28th hospital day. Peri-operative CT scaning and magnetic resonance imaging showed lesions of the right temporal lobe and right-dominant orbitofrontal regions including bilateral rectal and medial orbital gyri, and the intact left temporal lobe. Two pathogeneses can be thought of and the whole picture of KBS following ASDH can arise even though one (left in this case) temporal lobe is preserved, 1) in which associated orbitofrontal lesions of the frontal lobes may correlate with occurrence of KBS, or 2) cerebral blood hypoperfusion of both temporal lobes due to increased intracranial pressure and/or compression of both posterior cerebral arteries at the edge of the tentorium cerebelli occurs.

Ruptured de novo intracranial aneurysms

OBJECTIVE

We describe the actual state of ruptured de novo intracranial aneurysms to contribute to a guideline of follow-up for the patients with treated intracranial aneurysm.

METHODS

The authors retrospectively investigated 12 cases drawn from 483 consecutive cases of aneurysmal subarachnoid hemorrhage at our institute over a period of 22 years, in which a previously undemonstrated (hence "de novo") intracranial saccular aneurysm formed and ruptured after successful treatment of a prior aneurysm.

FINDINGS

The 12 cases constitute 2.5% of the 483 patients who left our hospital alive. Eleven cases were females and one was a male with a mean age of 55.7 years (range 29-75) at the first subarachnoid haemorrhage (SAH) and an interval between the first and the second rupture of 10.7 years (range: 2.6-23.8, standard deviation: 6.86, 95% confidence interval: 6.39-15.1). Four cases did not have risk factors such as hypertension, family history, smoking, multiple aneurysms, and moyamoya disease. None of these ruptured de novo aneurysms was at the same location as the original lesion. One-third (4 cases) of the de novo lesions in our series were found on the opposite side to each prior lesion.

INTERPRETATION

For not only young but also elder patients with a treated aneurysm (from the fifth decade to the sixth), especially for women, late angiography or alternative modalities of less-invasive examination should be considered. To detect de novo intracranial aneurysms before rupture, the search for a de novo aneurysm should be performed within 6.39 years after a previous examination that shows an aneurysm to be nonexistent, in view of the 95% confidence interval of the mean time to de novo aneurysmal rupture (6.39-15.1 years). If applied this survey, 75% (8 cases of 12 cases) of our de novo aneurysms would be detected before rupture.

Altered aquaporin 4 expression in muscles of Fukuyama-type congenital muscular dystrophy

This study was undertaken to investigate the expression of aquaporin 4 (AQP4) in the muscle plasma membrane of children with Fukuyama-type congenital muscular dystrophy (FCMD) at protein and mRNA levels. The biopsied six muscles with FCMD, six histochemically normal muscles and eight disease control muscles were analyzed by means of immunoblots, immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR). Immunoblots showed that the band of FCMD muscle extracts stained with anti-AQP4 antibody was faint in comparison with that of normal muscle extracts. The immunohistochemistry revealed that most of the FCMD myofibers showed negative immunostaining with anti-AQP4 antibody, although the partially positive immunostaining of sporadic FCMD myofibers was noted. The immunoreactivity was positive with anti-dystrophin and anti-beta-spectrin antibodies in almost all FCMD myofibers. The quantitative RT-PCR demonstrated that the AQP4 mRNA level of the FCMD muscles was markedly reduced. On the basis of these findings, we conclude that the expression of AQP4 in FCMD myofibers is reduced and the reduced content of AQP4 mRNA in FCMD muscles may be related to the decreased expression of AQP4 at the muscle plasma membrane of FCMD myofibers.

Mapping of quantitative trait loci associated with ultraviolet-B resistance in rice (Oryza sativa L.)

The detection of quantitative trait loci (QTLs) associated with UV-B resistance in rice should allow their practical application in breeding for such a complex trait, and may lead to the identification of gene characteristics and functions. Considerable variation in UV-B resistance exists within cultivated rice (Oryza sativa L.), but its detailed genetic control mechanism has not been well elucidated. We detected putative QTLs associated with the resistance to enhanced UV-B radiation in rice, using 98 BC(1)F(5) (backcross inbred lines; BILs) derived from a cross between Nipponbare (a resistant japonica rice variety) and Kasalath (a sensitive indica rice variety). We used 245 RFLP markers to construct a framework linkage map. BILs and both parents were grown under visible light with or without supplemental UV-B radiation in a growth chamber. In order to evaluate UV-B resistance, we used the relative fresh weight of aerial parts (RFW) and the relative chlorophyll content of leaf blades (RCC). The BIL population exhibited a wide range of variation in RFW and RCC. Using composite interval mapping with a LOD threshold of 2.9, three putative QTLs associated with both RFW and RCC were detected on chromosomes 1, 3 and 10. Nipponbare alleles at the QTLs on chromosome 1 and 10 increased the RFW and RCC, while the Kasalath allele at the QTL on chromosome 3 increased both traits. Furthermore, the existence of both QTLs on chromosomes 1 and 10 for UV-B resistance was confirmed using chromosome segment substitution lines. Plants with Kasalath alleles at the QTL on chromosome 10 were more sensitive to UV-B radiation than plants with them on chromosome 1. These results also provide the information not only for the improvement of UV-B resistance in rice though marker-associated selection, but also for the identification of UV-B resistance mechanisms by using near-isogenic lines.

Nested PCR for detection of mutans streptococci in dental plaque

AIMS

Mutans streptococci such as Streptococcus mutans and Streptococcus sobrinus have been implicated in human dental caries. In an attempt to develop a rapid and sensitive method for detecting Strep. mutans and Strep. sobrinus in dental plaque, a nested PCR amplification based on the 16S rRNA gene was employed.

METHODS AND RESULTS

A universal set of PCR primers for bacterial 16S rRNA gene was introduced for the first PCR, and then two sets of primers specific for the 16S rRNA gene sequences of either Strep. mutans or Strep. sobrinus were used for the second PCR. Eighteen plaque samples were analyzed, and a nested PCR was shown to be more sensitive for detecting Strep. mutans and Strep. sobrinus than direct PCR.

CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY

The 16S rRNA gene-based nested PCR method is a rapid and sensitive method for the detection of mutans streptococci, and may also be suitable for carrying out large-scale studies on the cariogenicity of mutans streptococci.

A gene for a Class II DNA photolyase from Oryza sativa: cloning of the cDNA by dilution-amplification

Ultraviolet radiation induces the formation of two classes of photoproducts in DNA-the cyclobutane pyrimidine dimer (CPD) and the pyrimidine [6-4] pyrimidone photoproduct (6-4 product). Many organisms produce enzymes, termed photolyases, which specifically bind to these lesions and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. Two classes of photolyases (class I and class II) repair CPDs. A gene that encodes a protein with class II CPD photolyase activity in vitro has been cloned from several plants including Arabidopsis thaliana, Cucumis sativus and Chlamydomonas reinhardtii. We report here the isolation of a homolog of this gene from rice (Oryza sativa), which was cloned on the basis of sequence similarity and PCR-based dilution-amplification. The cDNA comprises a very GC-rich (75%) 5; region, while the 3; portion has a GC content of 50%. This gene encodes a protein with CPD photolyase activity when expressed in E. coli. The CPD photolyase gene encodes at least two types of mRNA, formed by alternative splicing of exon 5. One of the mRNAs encodes an ORF for 506 amino acid residues, while the other is predicted to code for 364 amino acid residues. The two RNAs occur in about equal amounts in O. sativa cells.