The expression of a barley HvNAS1 nicotianamine synthase gene promoter-gus fusion gene in transgenic tobacco is induced by Fe-deficiency in roots.

Nicotianamine (NA) is a precursor for mugineic acid-family phytosiderophores, which are a critical component of the Fe aquisition process in graminaceous plants. In addition, nicotianamine synthase (NAS) is strongly induced in these plants by Fe deficiency. NA is essential for Fe metabolism also in dicots, but NAS is not induced by Fe deficiency. We introduced a barley HvNAS1 promoter-gus fusion gene into tobacco. GUS activity was induced in the roots of these plants by Fe deficiency, and was constitutively expressed at a low level in their leaves.

Sisters homozygous for the spinocerebellar ataxia type 6 (SCA6)/CACNA1A gene associated with different clinical phenotypes.

Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease caused by a CAG repeat expansion in the CACNA1A gene. The neurodegeneration that occurs in CAG repeat diseases is considered to share a common mechanism that may result in the gain of a toxic function related to the expanded polyglutamine tracts. However, the phenotypic expression in homozygotes for CAG repeat diseases has been controversial, and is not clearly related to a gain of functional mechanism. We identified a Japanese family with two sisters who were homozygous for the SCA6 with identical CAG repeat expansion (25/25). They showed an earlier age of onset (27 years in both) than their father (44 years), a heterozygote with an expanded allele showing the same CAG repeat length as the homozygotes (25/14). Interestingly, the two sisters showed differences in disease progression and severity, although the age of onset and CAG repeat length were identical. These findings strongly suggest that the gene dosage influences the age of onset, but other unknown factors are also important in the phenotypic expression of homozygous SCA6.

Helicobacter pylori populations in Peruvian patients.

Helicobacter pylori is an extremely diverse species. The characterization of strains isolated from individual patients should give insights into colonization and disease mechanisms and bacterial evolution. We studied H. pylori isolates from patients in the Japanese-Peruvian Polyclinic in Lima, Peru, by determining metronidazole susceptibility or resistance and by random amplified polymorphic DNA (RAPD) fingerprinting (a measure of overall genotype). Strains isolated from several biopsy specimens from each of 24 patients were studied. Both metronidazole-susceptible and -resistant strains were isolated from 13 patients, whereas strains of more than one RAPD type were isolated from only seven patients. We propose that the homogeneity in RAPD fingerprints for strains isolated from most persons reflects selection for particular H. pylori genotypes during chronic infection in individual hosts and the human diversity in traits that are important to this pathogen. Carriage of related metronidazole-resistant and -susceptible strains could reflect frequent metronidazole use in Peru and alternating selection for resistant and susceptible phenotypes during and after metronidazole therapy.

[Management of severe pain after extended maxillectomy in a patient with carcinoma of the maxillary sinus].

We treated a 65 year-old man with severe facial pain after extended maxillectomy due to carcinoma of maxillar sinus. He had been suffering from pain at rest, on mastication, or at treatment of surgical wound. Various kinds of analgesics had been tried, but his pain did not disappear. At 17 weeks after the operation, he came to our pain clinic. Because his pain was thought to be due to reflex sympathetic dystrophy (RSD), stellate ganglion blocks (SGB) were performed. After 5 administrations of SGB, pain was reduced markedly but the pain at treatment of wound persisted. We thought that persistent pain would need trigeminal nerve block. Then Gasserian ganglion block was performed directly through an open wound after the operation. After the Gasserian ganglion block, the pain was diminished remarkably. He could tolerate procedures for facial prosthesis. Pain control after the operation in this patient was very efficient to improve his quality of life. Serum concentrations of catecholamines, serotonin and substance P were measured. The levels of norepinephrine and serotonin are related to the mechanism of pain as seen in this patient.

Orientation of HLA-DNA gene and identification of a CpG island-associated gene adjacent to DNA in human major histocompatibility complex class II region.

We have constructed the detailed physical map of the HLA class II gene region by the pulsed field gel electrophoresis (PFGE) and cosmid walking technique. In this process, the DNA gene was found to be located telomeric to DPA1 with the 5'----3' orientation which is the same as the DPA1 and DPA2 genes, but opposite to the DQA1, DQA2 and DRA genes. This orientation is reverse to that of the counterpart gene in the rabbit major histocompatibility complex region. About 30 kb downstream from the DNA gene towards DOB, a CpG island characterized by clustered sites for rare cutting restriction enzymes and frequently associated with the 5' end of housekeeping genes was identified by PFGE and cosmid walking. From a complementary DNA (cDNA) library constructed from a Epstein-Barr virus-transformed B-cell line, a cDNA clone was isolated using the genetic probe from this CpG island. Its nucleotide sequences suggested that it represented a new non-HLA gene with a single copy which was of little genetic polymorphism and named NAT (DNA-associated transcript). Northern blot analysis showed that the NAT gene was expressed with a 4-kb transcript in all of tissues examined so far.