Disruption of the temporally regulated cloaca endodermal β-catenin signaling causes anorectal malformations

The cloaca is temporally formed and eventually divided by the urorectal septum (URS) during urogenital and anorectal organ development. Although congenital malformations, such as anorectal malformations (ARMs), are frequently observed during this process, the underlying pathogenic mechanisms remain unclear. β-Catenin is a critical component of canonical Wnt signaling and is essential for the regulation of cell differentiation and morphogenesis during embryogenesis. The expression of β-catenin is observed in endodermal epithelia, including URS epithelia. We modulated the β-catenin gene conditionally in endodermal epithelia by utilizing tamoxifen-inducible Cre driver line (Shh^CreERT2). Both β-catenin loss- and gain-of-function (LOF and GOF) mutants displayed abnormal clefts in the perineal region and hypoplastic elongation of the URS. The mutants also displayed reduced cell proliferation in the URS mesenchyme. In addition, the β-catenin GOF mutants displayed reduced apoptosis and subsequently increased apoptosis in the URS epithelium. This instability possibly resulted in reduced expression levels of differentiation markers, such as keratin 1 and filaggrin, in the perineal epithelia. The expression of bone morphogenetic protein (Bmp) genes, such as Bmp4 and Bmp7, was also ectopically induced in the epithelia of the URS in the β-catenin GOF mutants. The expression of the Msx2 gene and phosphorylated-Smad1/5/8, possible readouts of Bmp signaling, was also increased in the mutants. Moreover, we introduced an additional mutation for a Bmp receptor gene: BmprIA. The Shh^CreERT2/+; β-catenin^flox(ex3)/+; BmprIA^flox/− mutants displayed partial restoration of URS elongation compared with the β-catenin GOF mutants. These results indicate that some ARM phenotypes in the β-catenin GOF mutants were caused by abnormal Bmp signaling. The current analysis revealed the close relation of endodermal β-catenin signaling to the ARM phenotypes. These results are considered to shed light on the pathogenic mechanisms of human ARMs.

Tracer experiment and RTD analysis of DAF separator with bar-type baffles

This paper describes the development of a new dissolved air flotation (DAF) separator with a flow streamlining baffle to improve solid separation efficiency. The analysis of the RTD (residence time distribution) curves indicated that the parameter θ(10) (dimensionless time at which 10% of tracer has discharged) increased from 0.38 for control reactor to 0.54 for the test reactor, suggesting significant reduction in short circuit flow. The RTD curves were also used to develop a compartment model for white water (rich in micro-bubbles and water flow is turbulent) and clear water (little or no air content and water flow is quiescent) zones in the reactor using a series of CSTR (continuous stirred tank reactors) and plug flow regime respectively. The proportion of the volume occupied by the white water zone was different in control and test configurations. In the test reactor, the fraction of the clear water zone was found to increase from 6 to 37%, resulting in improvement of the suspended solid (SS) removal efficiency from 97 to 99%.

Cigarette smoking is associated with the reduction of lymphokine-activated killer cell and natural killer cell activities

Lymphokine-activated killer (LAK) cell and natural killer (NK) cell activities were determined in a group of healthy individuals with differing smoking habits. The study population consisted of 54 Japanese males, including 23 smokers, 8 ex-smokers and 23 non-smokers. Peripheral blood mononuclear cells (PBMC) were isolated and used as effector cells. LAK cells were generated by incubation of PBMC with interleukin-2 for 72 h. LAK cell activity against NK-resistant Raji cells and NK cell activity against NK-sensitive K562 cells were examined by 4-h51Cr-release assay. LAK cell activity in the smokers was significantly lower than that in the nonsmokers. The smokers showed significantly lower NK cell activity than the nonsmokers, whereas NK cell activity of the ex-smokers was comparable to that of the non-smokers. The proportion of NK cells (CD3-16+56-, CD3-16-56+, or CD3-16+56+ cells) in the smokers was significantly lower than that in the nonsmokers. The present study demonstrates for the first time that cigarette smokers have lower LAK cell activity than nonsmokers.

Enhancement of the specific growth rate of Thiobacillus ferrooxidans by diatomaceous earth

Diatomaceous earth is an effective carrier with a large surface area on which Thiobacillus ferrooxidans adsorbs, and enhances the oxidation rate of ferrous ions by the bacterium. The adsorption of T. ferrooxidans on diatomaceous earth was expressed by the Henry isotherm, and reached equilibrium within five minutes. The enhancement was due to an increase in the growth rate of the adsorbed cells, which were so active that their specific growth rate calculated using a Monod-type equation was higher than that of the free cells in the liquid phase.

Acute monocytic leukaemia in a cat

A three-year-old cat with lymphadenopathy, non-regenerative anaemia and marked leucocytosis (171.3 x 10(9) white blood cells/l) was diagnosed with monocytic leukaemia and treated with a combination of anticancer drugs. A number of mature and immature monocyte-like cells were detected in the peripheral blood and bone marrow; they proved to be monocytic cells by cytochemical examination and an analysis of their cell surface phenotype, indicating that the cat suffered from acute myeloid leukaemia, subclassified as monocytic leukaemia (M5). Treatment with cytarabine, doxorubicin, vincristine and prednisolone greatly reduced the number of blast cells in the cat's peripheral blood and bone marrow. The cat was in partial remission for 67 days and survived for 95 days after it was first examined.

Expression of low-frequency Ala108Pro substitution in the platelet glycoprotein Ibbeta gene

We determined the gene frequency of the glycoprotein (GP) Ibbeta Ala108Pro substitution. The Pro108 allele was not found in 208 healthy Japanese and 200 healthy Caucasians. In vitro expression studies showed surface expression of the GPIbbeta Pro108 variant, suggesting the possibility of the involvement of the substitution as an alloantigen.

Math6, a bHLH gene expressed in the developing nervous system, regulates neuronal versus glial differentiation

BACKGROUND

Whereas multiple basic helix-loop-helix (bHLH) genes are expressed in the developing nervous system, they account for the differentiation of only subsets of neurones, suggesting that there may be as-yet unidentified bHLH genes.

RESULTS

We have isolated a novel bHLH gene, designated Math6, a distant mammalian homologue of the Drosophila proneural gene atonal. Structural analysis of the Math6 gene demonstrated that the coding region is divided into three exons, whereas that of other atonal homologues is present in a single exon, indicating that the genomic structure of Math6 is unique among the atonal homologues. Math6 is initially expressed by neural precursor cells in the ventricular zone, but later by subsets of differentiating and mature neurones such as hippocampal neurones and cerebellar Purkinje cells. Mis-expression of Math6 with retrovirus in the developing retina induced neurogenesis, while inhibiting gliogenesis, without affecting cell proliferation and death.

CONCLUSIONS

These results show that cells which would normally differentiate into glia adopted the neuronal fate by mis-expression of Math6, indicating that Math6 promotes neuronal vs. glial fate determination in the nervous system.

Presence of Propionibacterium acnes in blood components

BACKGROUND

Sterility testing, as part of the QC of blood components at the Japanese Red Cross Aichi Blood Center between April 1998 and March 2000, showed that 10 of 5568 tested blood components (0.18%), all of which were RBC concentrates, were contaminated with bacteria. Nine isolates were Propionibacterium acnes and one was Staphylococcus capitis.

STUDY DESIGN AND METHODS

To investigate the molecular relatedness of eight available P. acnes isolates, 16S rRNA gene analysis and random amplified polymorphic DNA (RAPD) analysis were performed.

RESULTS

DNA sequencing analysis of the 16S rRNA gene showed that five isolates were identified as distinct strains and that three had identical sequences. RAPD analysis in the latter three isolates showed that two exhibited indistinguishable banding patterns that differed from that of the third isolate.

CONCLUSION

P. acnes was the most frequent contaminant of blood components, and six of eight isolates were molecularly unrelated. Further studies are necessary to investigate the precise mechanisms of contamination.

The basic helix-loop-helix gene hesr2 promotes gliogenesis in mouse retina

Members of a subclass of hairy/Enhancer of split [E(spl)] homologs, called hesr genes, are structurally related to another subclass of hairy/E(spl) homologs, Hes genes, which play an important role in neural development. To characterize the roles of hesr genes in neural development, we used the retina as a model system. In situ hybridization analysis indicated that all hesr genes are expressed in the developing retina, but only hesr2 expression is associated spatially with gliogenesis. Each member was then misexpressed with retrovirus in the retinal explant cultures prepared from mouse embryos or neonates, which well mimic in vivo retinal development. Interestingly, hesr2 but not hesr1 or hesr3 promoted gliogenesis while inhibiting rod genesis without affecting cell proliferation or death, suggesting that the cells that normally differentiate into rods adopted the glial fate by misexpression of hesr2. The gliogenic activity of hesr2 was more profound when it was misexpressed postnatally than prenatally. In addition, double mutation of the neuronal determination genes Mash1 and Math3, which increases Müller glia at the expense of bipolar cells, upregulated hesr2 expression. These results indicate that, among structurally related hesr genes, only hesr2 promotes glial versus neuronal cell fate specification in the retina and that antagonistic regulation between hesr2 and Mash1-Math3 may determine the ratios of neurons and glia.

Rapid screening method to detect mutations in CYP21, the gene for 21-hydroxylase

To facilitate a rapid and practical molecular diagnosis of 21-hydroxylase deficiency (21-OHD), we developed a polymerase chain reaction (PCR) test in which only the 21-OH gene (CYP21) is amplified. We applied the test to diagnose 23 patients with salt-wasting type of 21-OHD. The upstream and downstream sequences of CYP21 have been specifically amplified by using a primer set containing the 8-bp deletion sequence of exon 3, which is distinct from its pseudogene CYP21P. The amplified PCR products were further subjected to mutation detection by restriction analysis: E1PL by AciI, I2g by PstI, E63a by DraIII, E7VL by ApaLI, E8non by PstI, and E8RW by AciI. To detect delections and/or gene conversions occurring on exon 3, we used the method described by Rumsby and Honour [1990: J Med Genet 27:676-678]. Our method is able to elucidate 8 common CYP21 mutations by using only 3 primer pairs and 4 restriction enzymes. The overall detection ratio of abnormal haplotypes by this method was over 95%, indicating that our method is practical and useful, particularly for carrier detection.

A novel mutation (296 del G) of the SOX90 gene in a patient with campomelic syndrome and sex reversal

The human SOX9 gene is responsible for the campomelic syndrome (CMPS) and sex reversal. This gene encodes a transcription factor containing a DNA binding domain homologous to the SRY high mobility group (HMG) domain. A novel mutation of SOX9, i.e. a single G deletion in one allele at nt 296 from A of the first ATG in the open reading frame, was identified in a patient with CMPS with sex reversal. The deletion resulted in a frameshift mutation upstream of the HMG box and a stop codon 30 bp downstream of the HMG box. The predicted truncated SOX9 protein contained 108 amino acids instead of the 509 amino acids of the normal SOX9 protein, removing nearly 80% of the SOX9 protein, including the HMG and the C-terminal transactivation domain. Most patients with CMPS reported previously died within the neonatal period. Our findings that the patient has survived, although has been in daily need of mechanical ventilation support for 5 years and 3 months despite a severely impaired SOX9 protein, do not support a linear relationship between the type of mutation and severity of the clinical outcome.

Homozygous Pro74-->Arg mutation in the platelet glycoprotein Ibbeta gene associated with Bernard-Soulier syndrome

Bernard-Soulier syndrome (BSS) is an autosomal recessive bleeding disorder due to quantitative or qualitative abnormalities in the glycoprotein (GP) Ib/IX/V complex, the platelet receptor for von Willebrand factor. This complex is composed of four subunits, GPIbalpha, GPIbbeta, GPIX and GPV. We describe here the genetic basis of the disorder in a patient with BSS. Flow cytometric analysis of the patient's platelets showed greatly reduced GPIbalpha and GPIX surface expression. Immunoblot analysis disclosed absence of GPIbalpha, GPIbbeta and GPIX in the platelets. DNA sequencing analysis revealed a novel missense mutation in the GPIbbeta gene that converts Pro (CCG) to Arg (CGG) at residue 74. Homozygosity of the mutation was confirmed by allele-specific restriction analysis, chromosome 22 microsatellite analysis and quantitative Southern blotting. The mutant GPIbbeta was normally transcribed. Transient transfection studies confirmed that mutant GPIbbeta impairs surface expression of GPIb/IX, showing that the mutation is responsible for a BSS phenotype observed in the patient.

The validity and reproducibility of an oral rating index as a measurement of gingival health care and oral hygiene level in adults

The purpose of this study was to investigate the validity and reproducibility of an oral rating index (ORI) as a conceptual measurement of "gingival health care" level in adults. The study was conducted on 163 patients who received medical examinations and attended for dental checkups at a hospital. The score of the ORI was recorded as excellent (+2), good (+ 1), questionable (0), poor (-1) or very poor (-2). The validity of the ORI was investigated by comparing it with: Jackson's gingivitis index (GI); Greene & Vermillion's debris index (DI) and calculus index (CI); probing pocket depth (PPD); and percentage of bleeding on probing (%BOP). The intra- and inter-examiner reproducibility of the ORI was assessed on a flat screen using patients' color transparencies of the mouth. The ORI had significantly negative correlations with the GI, DI, CI, and PPD (p<0.001). The K values were 0.604-0.672 for intra-examiner reproducibility, and 0.441-0.449 for inter-examiner reproducibility. The present study suggests that the ORI has moderate to good intra-examiner and inter-examiner reproducibility. Mouth examination using the ORI appears to provide useful information that will enable a dental professional or health educator to make sensible decisions on the type and level of oral health instruction according to adults' gingival health care level.

Two novel mutations of SURF1 in Leigh syndrome with cytochrome c oxidase deficiency

Cytochrome c oxidase (COX) deficiency is the most common cause of Leigh syndrome (LS). COX consists of ten nuclear-encoded and three mtDNA-encoded structural subunits. Although the nucleotide sequences of all 13 genes are known, no mutation was found in nuclear-encoded subunit genes of COX-deficiency patients. Zhu et al. (1998) and Tiranti et al. (1998) found nine mutations in the surfeit 1 (SURF1) gene in LS families with COX deficiency. The mouse surfeit gene cluster consists of six closely spaced housekeeping genes unrelated by sequence homology. Except for the Surf3 gene, the function is still not known. The juxtaposition of at least five of the surfeit genes is conserved between birds and mammals. We identified two novel mutations of SURF1 in a Japanese LS patient with COX deficiency using direct sequencing analysis. Firstly, a 2-bp deletion at nucleotide position 790 (790delAG) in exon 8 was found, which shifts the reading frame such that the mutant protein has a completely different amino acid sequence from codon 264 to the premature stop codon at 290. Secondly, we found a T-to-G transversion at nucleotide 820, resulting in the substitution of tyrosine by aspartic acid at codon 274 (Y274D). We also studied the parents' genes, and found that the Y274D mutation was in his father and the 790delAG mutation was in his mother heterozygously. Therefore, we concluded that the patient was a compound heterozygote with these mutations. These are the first pathogenetic SURF1 mutations identified in a Japanese family.

[Effect of intravenous immunoglobulin therapy in a case of idiopathic recurrent brachial and lumbosacral plexopathy]

We report a case of a 23-year-old woman with idiopathic brachial and lumbosacral plexopathy who presented a relapsing course of weakness and numbness following acute onset of pain in the right shoulder or pelvic girdle area. On her first admission, the patient recovered gradually with oral prednisolone. But after about 1 year, her symptoms worsened. In the second admission, oral prednisolone had no effect on her symptoms, so intravenous immunoglobulin (IVIG; 0.1 g/kg/day, 5 days) therapy was tried. The patient improved about 2 weeks after IVIG therapy. About 1 year later, her symptoms worsened and was administered again. In the third admission, IVIG therapy of which dose was the same as that in the previous admission had an effect on her symptoms. The dose of IVIG in our case was relatively low, compared with those in cases reported before (0.2-2 g/kg/day). This findings suggest that a relatively low-dose IVIG therapy is effective for idiopathic plexopathy.

Study of rapidity and quality for the VITEK susceptibility cards with 45 wells

VITEK 45 wells Card was evaluated. Recent clinical isolates of gram-positive cocci (107) and gram-negative bacilli (179) were antimicrobial susceptibility testing by VITEK system in comparison with MIC-2000 system. The antimicrobial susceptibility results were available within of 8 h for gram-positive cocci without a part of MRSA. Enterobac-teriaceae were available within of 8 h and Pseudomonas aeruginosa were from 8 to 11 h. The antimicrobial susceptibility data had disagreement of 60% with EM, 46% with CLDM for Enterococcus faecium, 50% with CMZ for Citrobacter freundii, and 71% with CTM for Morganella morganii, whereas it was satisfactory agreement of 97.5% for gram-positive cocci and 98.2% for gram-negative bacilli. In using this procedure it was possible to provide accurate and rapid results of anti-microbial susceptibility tests for all organisms.

Changes in muscle strength properties caused by harvesting of autogenous semitendinosus tendon for reconstruction of contralateral anterior cruciate ligament

A prospective study was conducted of how the muscle strength of the donor knee is affected by harvesting of the autogenous semitendinosus tendon (St) for use as a substitute graft material in cruciate ligament reconstruction. There were 25 patients from whom only the St was harvested from the contralateral (i.e., healthy/donor) knee. Using a Biodex System II (Biodex, New York, NY), the strength of the donor knee was measured during both extension and flexion, both before and 12 months after the tendon harvesting procedure. A comparative study was made of the preharvest and postharvest values for the peak torque and peak torque angle in the isokinetic contraction. There were no statistically significant differences between the preharvest and postharvest peak torque values of the donor knee. However, the peak torque angle decreased significantly after the tendon harvest; the range of the mean decrease was from 11.7 degrees to 15.0 degrees. This indicates that there was a change to a small flexion angle (P < .05). After the tendon harvest, regardless of the applied angular velocity, more than 80% of the cases showed a change of torque curve shape in which there was no peak in the latter half, and the position of the peak was shifted to the left. In conclusion, the results of this study indicate that harvesting of the autogenous St does not affect the peak torque, but the peak torque angle during flexion of the donor knee is reduced.

The detection model of recognition using know and remember judgments

The signal detection model for know and remember recognition judgments was tested in two experiments. In Experiment 1, two predictions of the model were tested: (1) that measures of memory sensitivity, A', are equivalent in value when based on either the recognition (know or remember) criterion or on the remember criterion; and (2) that there is a positive correlation between recognition bias and the proportion of know judgments that are hits, but no correlation between recognition bias and proportion of remember hits (Donaldson, 1996). Both predictions were supported by the data. In Experiment 2, the context of test items was manipulated to make it more or less similar to learning context. The detection model requires that memory sensitivity be the same for both recognition and remember judgments, regardless of test context. Alternatively, if remember judgments reflect only the retrieval of episodic information from memory, the two measures of memory sensitivity should become more disparate in value as learning and test context are made more similar. Memory sensitivity was generally the same in value for recognition and remember criteria but different across context conditions, thus supporting the detection model. The nature of the memory continuum used in detection theory is also discussed.

[A case of livedo vasculitis associated with mononeuritis multiplex]

Livedo vasculitis is characterized by recurrent livedo reticularis of lower extremities and the histopathological findings of segmental hyalinizing vasculitis in the skin. We report a case of a 26-year-old female who manifested mononeuritis multiplex 7 years after the onset of livedo vasculitis. She showed sensori-motor disturbances in the right median and ulnar nerves and sensory deficits of the bilateral peroneal nerves. Sural nerve biopsy revealed a remarkable loss of large and small myelinated fibers and a few vasculitic changes. Steroids therapy was effective for these neurological symptoms. But paroxysmal numbness appeared later recurrently in the regions of affected nerves with painful ulcerations in the right leg. Laboratory tests indicated increased levels of serum thrombin-antithrombin complex (TAT), and antithrombotic drugs (argatroban) remarkably ameliorated the recurrent symptoms and skin lesions. These findings suggest that the pathogenesis of livedo vasculitis might be related to alterations of the blood coagulation system.

Arthroscopic studies of variants of the anterior horn of the medical meniscus

The objective of this study was to arthroscopically analyse the morphology and dynamics of variants of the anterior horn of the medial meniscus of the knee (VAMM) and to then consider the pathological significance of these variants. VAMM was defined as knees in which the anterior horn of the medial meniscus is not attached to the tibia. Between April 1992 and March 1995, arthroscopy was performed on 953 knees of 903 patients. At the time of this examination, observation and probing were performed to determine the condition of the synovium, the synovial plica, the cartilage in all compartments, the meniscus, the cruciate ligaments, and the popliteal tendon. In particular, detailed examination was made of the anterior horn of the medial meniscus with regard to the point of insertion to the tibia and the degree of movement in knee flexion/ extension. Cases of VAMM diagnosed on the basis of the arthroscopic findings were classified into the following four categories: the ACL (anterior cruciate ligament) type, where the anterior horn of the medial meniscus was attached to the ACL; the transverse ligament type, where the anterior horn of the medial meniscus was attached to the transverse ligament; the coronary ligament type, where the anterior horn of the medial meniscus was attached to the coronary ligament; and the infrapatellar fold type, where the anterior horn of the medial meniscus was attached to the infrapatellar synovial fold. These patients were then analyzed with regard to the arthroscopic findings and the intra-articular lesions other than VAMM. In 98 (10.9%) of the total patients, 103 knees were classified as VAMM. Classification of those 103 knees using the above criteria showed 39 ACL type knees, 51 transverse ligament type knees, 11 coronary ligament type knees, and 2 infrapatellar fold type knees. The arthroscopic findings indicated that the anterior horn of the medial meniscus was not attached directly to the tibia in any of these knees. Probing and flexion/extension of the knee revealed hypermobility at the anterior horn of the medial meniscus. In this study, anterior knee pain syndrome was diagnosed in 12 (11.7%) of the 103 VAMM knees. In addition, there was no clear history of trauma in 20 of 23 knees found to have an isolated medial meniscus tear. In these cases, even detailed arthroscopic observation proved the causes of the symptoms or injury. On the basis of these findings, we surmised that the anterior portion shows hypermobility at the time of flexion/extension of the knee, regardless of the type of VAMM. In this study, we discussed the possibility that the existence of VAMM may become the cause of pain or injury to the meniscus.

In vitro method for assessing hepatic drug metabolism

We investigated an in vitro metabolic test using rat liver biopsy samples by TLC-autoradioluminography (ARLG), with a view to developing a method to rapidly assess the drug metabolizing activities of individual patients. Drug metabolizing activity was measured in liver biopsy samples collected from rats in four groups: a female control group, male control group, phenobarbital (PB)-administered male group and cimetidine (CM)-administered male group. The productivity of metabolites of 7-ethoxycoumarin (7-EC), debrisoquine (DB) and diazepam (DZ), respectively, was lower in the female control group than in the male control group, but there were no differences in the productivity of metabolites of 5-fluorouracil (5-FU) and tolbutamide (TB), respectively, between the male and female control groups. Those of 7-EC, TB and DZ were higher in the PB-administered group than in the male control group, but those of DB did not differ between these two groups. Those of 5-FU, 7-EC, TB, DB and DZ were lower in the CM-administered group than in the male control group. Using TLC-ARLG, we could detect drug metabolites in rat liver biopsy samples in a relatively short time span at low concentrations similar to those in vivo. We could also measure drug metabolizing activity in cases with and without the involvement of cytochrome P450. When applied in clinical metabolic tests, TLC-ARLG is expected to be useful for assessing the drug metabolizing activities of patients.

Healthy lifestyles are associated with higher lymphokine-activated killer cell activity

BACKGROUND

To investigate the association between lifestyle factors and immune responses to tumors, we determined lymphokine-activated killer (LAK) cell activity and proportions of lymphocyte subsets in 54 healthy males.

METHODS

LAK cell activity was determined by 51Cr release assay. The proportions of natural killer cells (CD3-16+56-, CD3-16-56+ or CD3-16+56+ cells), helper/ inducer T cells (CD4+8-), and cytotoxic/suppressor T cells (CD4-8+) in lymphocytes were also determined by flow cytometry. Subjects were classified into two groups, good or poor overall lifestyle, according to their answers on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, physical exercise, mental stress, sleeping pattern, nutritional balance, eating breakfast, working pattern).

RESULTS

Subjects with good health practices regarding smoking showed significantly higher LAK cell activity. They also showed a significantly higher proportion of natural killer cells and a lower proportion of helper/inducer T cells. LAK cells activity was significantly higher in subjects with a good overall lifestyle than in those with a poor overall lifestyle after controlling for the effects of smoking. There were no significant differences in the proportions of lymphocyte subsets between the two lifestyle groups.

CONCLUSIONS

Lifestyle factors are associated with LAK cell activity and the proportion of lymphocyte subsets.

Positron emission tomography in diagnosing brainstem vascular lesions that cause abnormal eye movements

PURPOSE

To evaluate the efficacy of positron emission tomography (PET) in aiding in the diagnosis of brainstem infarctions that cause abnormal eye movements.

METHOD

Cerebral glucose metabolism was examined by PET with 18F-fluorodeoxyglucose as a tracer in five normal control subjects and six patients with abnormal eye movements. The PET images were registered to and superimposed on magnetic resonance images (MRIs).

RESULTS

All control subjects showed little asymmetry of glucose metabolism in the brainstem, whereas all six patients demonstrated areas of low glucose metabolism in the brainstem. Areas of low metabolism seen by PET were wider than they appeared to be by MRI; MRIs even appeared normal in some patients. Asymmetry index measurements at the level of the ischemic lesion ranged between 19% and 45%.

CONCLUSIONS

Positron emission tomography detected metabolic abnormality in patients with brainstem lesions that caused abnormal eye movements. Superimposing PET images on MRIs accurately localized abnormally low metabolism in the brainstem. Combined imaging with PET and MRI can be used to diagnose ischemic lesions in the brainstem from functional (PET) and morphologic (MRI) viewpoints.

Mercuric ion uptake by Escherichia coli cells producing Thiobacillus ferrooxidans merC

The merC gene of Thiobacillus ferrooxidans was overexpressed in Escherichia coli under the control of the tac promoter. MerC protein synthesized in E. coli has a N-terminal amino acid sequence of S-A-I-X-R-I-I-D-K-I-G-I-V-G-, which agrees with the amino acid sequence deduced from its nucleotide sequence except that an initiating methionine residue was removed. The MerC protein was localized in the particulate (membrane) cell fraction, and not in the soluble cytoplasmic fraction. E. coli cells carrying a plasmid containing the tac promoter-directed merC showed 203Hg2+ uptake in an isopropyl-1-thio-beta-D-galactopyranoside (IPTG)-dependent manner.

[Thymic carcinoid associated with ectopic ACTH syndrome]

A 63-year-old man was admitted to Sendai Red Cross Hospital complaining of chest and back pain associated with Cushing's syndrome. Based on the abnormally high levels of ACTH, cortisol, and CRH in plasma the patient was suspected of having ectopic ACTH syndrome. Histological examination of an extirpated rib and pleural tumor led to the diagnosis of atypical carcinoid tumor, with ribbon and festoon formation, immunoreactivity to ACTH, NSE, Chg-A, and argyrophilia in the tumor cells. Anti-cancer chemotherapy was not effective, and the patient died within a year after the onset of Cushing's syndrome. An autopsy revealed that the patient had an ACTH- and CRH-producing thymic carcinoid with metastases to many organs. The pituitary was atrophic with Crooke's hyaline change. There were many CRH-positive cells in the paraventricular nuclei of the hypothalamus, where no remarkable pathologic changes were seen.

Functional neuroanatomy of visual object naming: a PET study

BACKGROUND

The ability to name objects depends partly on visual perception. We used positron emission tomography (PET) to measure activity-related changes in regional cerebral blood flow (r-CBF) in order to identify regions of the brain activated during visual object naming.

METHODS

Four right-handed volunteers were recruited. Following an intravenous injection of 15O-labeled water, r-CBF was measured during visual object naming, counting numbers, and resting. PET and MRI images were coregistered, the size of the brain was proportionally adjusted in each axis to Talairach's and Tournoux's atlas, and the comparison of stimulated versus resting blood flow images revealed activated brain regions.

RESULTS

In the subtraction of resting from naming, activation was observed in the bilateral primary visual cortex, bilateral fusiform gyrus, left lingual gyrus, bilateral inferotemporal cortex, bilateral inferior frontal gyrus, bilateral precentral gyrus, anterior cingulate gyrus, left parietal operculum, and left putamen. In the subtraction of counting from naming, most of the those areas were activated, but no significant activity was observed in the left lingual gyrus, left parietal operculum, or bilateral precentral gyrus (motor cortex). The areas activated with the paradigm included those dedicated to visual perception (primary and associate visual cortex), visual recognition (inferior temporal cortex), and phonological output (Broca's area).

CONCLUSION

Our results indicated that the major neural network from occipital lobe to frontal cortex, which is mainly involved in the ventral visual pathway, demonstrated activation in these tasks. Result of this study will serve as base line data for analyzing the findings in patients with impaired visual perception.

A case of renovascular hypertension associated with neurofibromatosis

We report a case of renovascular hypertension associated with neurofibromatosis complicated by moderate proteinuria. A 16-year-old female was admitted to Kensei General Hospital with a complaint of headache and a blood pressure of 230/120 mm Hg. She was referred to us for further evaluation of the hypertension. On examination, cafe-au-lait spots were seen over her extremities and flank, and a bruit was heard in the right upper abdomen. The urinary protein excretion was 2.1 g/day. The plasma renin activity (PRA) and plasma aldosterone concentration were high, but the levels of catecholamines were normal. The renogram was asymmetric and on venous sampling, the PRA in the right renal vein was 58.3 ng/ml/h and that in the left was 22.1 ng/ml/h. CT scan detected an approximately 10-mm mass in the proximal right renal artery. Arteriography disclosed severe stenosis in the right renal artery and the superior mesenteric artery. Therefore, we concluded that her hypertension resulted from stenosis of the right renal artery due to neurofibromatosis. Accordingly, she underwent an operation to reconstruct that artery. After the operation, her blood pressure and PRA normalized without administration of any anti-hypertensive drug and urinary protein disappeared.

Characteristics of participants and non-participants in annual mass screening for oral cancer in 60-year-old residents of Tokoname city, Japan

Three thousand one hundred and twenty three 60-year-old residents of Tokoname city, Japan, were eligible to take part in an ongoing annual mass screening programme for oral cancer and precancer during the years 1986-1990. All received a mailed questionnaire to ascertain details of their personal circumstances, lifestyle factors and medical history. One thousand six hundred and sixty eight (53 per cent) responded and of these, 347 plus an additional 89 non responders, totalling 14 per cent of the sample, subsequently attended for screening. Those screened were significantly more likely than non participants to have taken part in other general health or cancer screening, to report past histories of diseases or conditions with severe subjective symptoms and to have access to the screening facility on foot, by bicycle or by car. There were no significant differences between the groups in their smoking habits or alcohol consumption. Ways of improving compliance in screening are considered and in particular, the need for further strengthening the complementary public education programme to increase its effectiveness is highlighted.

Pathogenesis of mucocutaneous lesions in Behçet's disease

Behçet's disease (BD) is characterized by recurrent oral aphthae, skin lesions, eye lesions, and genital ulceration. To determine the pathogenesis of BD, we performed histological and immunohistochemical studies of these mucocutaneous lesions, an assay of neutrophil activity, and HLA typing. Dense dermal or subcutaneous infiltrations of polymorphonuclear cells (PMN) without leukocytoclastic vasculitis were found in 28 of 57 lesions. Immunohistochemically, deposits of C3 on the vessels were found in 12 of 31 lesions. Deposits of immunoglobulin were not found except for one of IgM. C3 deposits and PMN infiltrations were significantly related (p < 0.05). PMN activity by polarization was enhanced; however, the results did not show a significant relationship with the PMN infiltrations or the C3 deposits. The incidence of HLA-B51 was significantly high in BD, but no significant relationship was found between HLA-B51 and the results of other examinations. These results suggest that the pathogenesis of BD lesions differs from that of collagen diseases and that C3 deposits on the vessels may play an important role in the development of mucocutaneous lesions where PMN have mainly infiltrated.

Effects of stem cell factor (SCF) on human marrow neutrophil, neutrophil/macrophage mixed, macrophage and eosinophil progenitor cell growth

The effects of stem cell factor (SCF) on the subpopulations of granulocyte/macrophage colony-forming units (CFU-GM) were examined. Hematopoietic progenitor cells were enriched from normal adult bone marrow specimens by immunomagnetic beads using an anti-CD34 antibody and lineage marker antibodies for positive selection and negative selection, respectively. SCF enabled neutrophil and neutrophil/macrophage mixed progenitors to respond to granulocyte/macrophage colony-stimulating factor (GM-CSF) or interleukin 3 (IL-3) and to develop the colony and further cluster formation. The neutrophil colonies stimulated by GM-CSF or IL-3 consisted mainly of immature cells, while the colonies stimulated by granulocyte colony-stimulating factor (G-CSF) consisted of mature neutrophils irrespective of the addition of SCF. In macrophage and eosinophil lineages, SCF augmented the colony formation in the presence of GM-CSF or IL-3, whereas the enhancement of total progenitor cell growth (colonies plus clusters) was not so marked as compared with the neutrophil lineage. Time-course observation revealed that SCF could stimulate macrophage and eosinophil progenitors to form colonies rapidly. These findings indicate that SCF acts on late myeloid progenitor cells in manners different from the lineages of commitment.

Identification of the purA gene encoding adenylosuccinate synthetase in Thiobacillus ferrooxidans

The purA gene of Thiobacillus ferrooxidans encoding adenylosuccinate synthetase [EC 6.3.4.4] was identified in the upstream region of the iro gene encoding Fe(II)-oxidase (J. Biol. Chem 267:11242-11247, 1992). The purA gene consisted of 1290 base-pairs, which translated into a 29-amino-acid protein. The gene is functionally active, because it is able to complement an Escherichia coli purA-deficient strain. The deduced gene product has a high degree (60.9%) of sequence identity with that (432 aa) of E. coli purA gene, and both the products share GDEGKGK-DETG-TKLD sequences which are supposed to be GTP-binding domain. The downstream region of the iro gene contained another open-reading frame (ORF) of 1218 bp, and this showed high homology (56.6% over 249 bp) with E. coli ORF-II, which is found as a second ORF and truncated form in the downstream region of the purA gene. Comparison of the gene organization in the flanking region of purA gene between T. ferrooxidans and E. coli is also described.

Hippocampal damage does not impair instrumental appetitive conditioning with delayed reinforcement

The present study evaluated the effects of bilateral hippocampal lesions on appetitive instrumental conditioning with delayed (5-s interval) reinforcement in rats. Acquisition of a bar press response was considerably slower than rates observed with immediate reinforcement; however, no significant differences between hippocampally lesioned and control groups were noted regarding training to criteria or ratio of responses to reinforcements. These results suggest that the hippocampus is not essential for the association of temporally discontinuous stimuli, and that deficits in other forms of associative learning, such as spatial cognition, must be mediated by the loss of other functions. Putative functions and underlying substrates are discussed for response modulation and sensory (cue relations) associations.

Chromosome alterations in peripheral lymphocytes as indices of lifestyle and genotoxicity

Short-term cultures of human lymphocytes were used to investigate the in vitro metabolism of benzene and its genotoxicity, and to monitor genetic health effects of lifestyles. Metabolic (S9) activation of benzene and its metabolites, catechol, hydroquinone, and phenol, caused an increase in sister-chromatid exchanges (SCEs) with different optimal concentrations of S9 mix for converting each compound into further reactive forms. The data indicate that catechol and hydroquinone can be optimally metabolized to produce reactive species, presumably benzo(semi)quinones, under conditions of lower metabolic activity than those necessary for phenol and benzene. We have further investigated the correlations between chromosome alterations (SCEs, structural aberrations and micronuclei) in peripheral lymphocytes and individual lifestyles. Healthy lifestyles, or "good health practices" examined were 1) not smoking, 2) not drinking too much alcohol, 3) doing physical exercise regularly, 4) sleeping more than 6 h per night, 5) keeping nutritional balance in meals, 6) not snacking, 7) having breakfast everyday, and 8) not having too much perceived stress. The persons were categorized into 3 groups having good, moderate and poor lifestyles by the number of good health practices they do. Mean frequencies of chromosome alterations in lymphocytes from men with poor lifestyles have been shown to be significantly higher than those in cells from men having good lifestyles.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrotransformation of Thiobacillus ferrooxidans with plasmids containing a mer determinant

The mer operon from a strain of Thiobacillus ferrooxidans (C. Inoue, K. Sugawara, and T. Kusano, Mol. Microbiol. 5:2707-2718, 1991) consists of the regulatory gene merR and an operator-promoter region followed by merC and merA structural genes and differs from other known gram-negative mer operons. We have constructed four potential shuttle plasmids composed of a T. ferrooxidans-borne cryptic plasmid, a pUC18 plasmid, and the above-mentioned mer determinant as a selectable marker. Mercury ion-sensitive T. ferrooxidans strains were electroporated with constructed plasmids, and one strain, Y4-3 (of 30 independent strains tested), was found to have a transformation efficiency of 120 to 200 mercury-resistant colonies per microgram of plasmid DNA. This recipient strain was confirmed to be T. ferrooxidans by physiological, morphological, and chemotaxonomical data. The transformants carried a plasmid with no physical rearrangements through 25 passages under no selective pressure. Cell extracts showed mercury ion-dependent NADPH oxidation activity.

Molecular cloning of the gene encoding Thiobacillus ferrooxidans Fe(II) oxidase. High homology of the gene product with HiPIP

The amino-terminal sequence of Thiobacillus ferrooxidans Fe(II) oxidase (linked to cytochrome c552) was determined, and the iro gene that encodes this enzyme was cloned using degenerate oligonucleotides as a probe. The DNA sequence of a region (856 base pairs) which encompasses the iro gene revealed that the enzyme was encoded by a 273-base pair open reading frame and consists of 90 amino acids, including a possible 37-residue signal sequence. The iro gene seems to be transcribed independently of any other gene because the transcriptional products are 0.45 and 0.6 kilobases in size. Current protein databases revealed that the iro gene product is a new member of the high redox potential iron sulfur proteins, which generally function in electron transport but do not show enzymatic activity.

The merR regulatory gene in Thiobacillus ferrooxidans is spaced apart from the mer structural genes

Two distinct merR genes, which regulate expression of the mercuric ion resistance gene (mer), of Thiobacillus ferrooxidans strain E-15 have been cloned, sequenced and termed merR1 and merR2. As a result of gene walking around two merR genes, it was found that these two genes were quite close in distance. The nucleotide sequence of the region (5,001 base pairs; PstI-EcoRI fragment) containing the merR genes was determined. Between the two merR genes, there were five potential open reading frames (ORFs). Two of these were identified as merC genes, and the other three as ORFs 1 to 3. ORFs 1 to 3 show significant homology to merA, tnsA from transposon Tn7, and merA, respectively. Both merR genes consist of a 408 bp ORF coding for 135 amino acids. Their gene products, MerR1 and MerR2, differed at three amino acid positions, and shared 56-57% and 32-38% identity with the MerRs from other Gram-negative and Gram-positive bacteria, respectively. Competitive primer extension analysis revealed that both regulatory genes were expressed in the host cells. These merR genes were located more than 6 kb from either end of the mer structural genes (merC-merA). This is the first example of merR being separated from the mer structural genes. The two merC genes, each of which coded for a 140-amino-acid protein, appeared to be functionally active because Escherichia coli cells carrying these merC genes on plasmid vectors showed hypersensitivity to HgCl2. However, ORFs 1 and 3, which were homologous to merA, seemed to be inactive both structurally and enzymatically. The gene arrangement in this region took on a mirror image, with the truncated tnsA as the symmetrical centre. It is suggested that the Tn7-like factor may have participated in gene duplication events of the mer region, and in its chromosomal integration.

Evidence for two sets of structural genes coding for ribulose bisphosphate carboxylase in Thiobacillus ferrooxidans

Previously, we reported the cloning of the ribulose-1,5-bisphosphate carboxylase genes (rbcL1-rbcS1) of Thiobacillus ferrooxidans Fe1 (T. Kusano, K. Sugawara, C. Inoue, and N. Suzuki, Curr. Microbiol. 22:35-41, 1991). With these genes as probes, a second set of ribulose-1,5-bisphosphate carboxylase genes (rbcL2-rbcS2) was identified in the same strain and cloned. rbcL1 and rbcL2 encode the large subunits, and rbcS1 and rbcS2 encode the small subunits. Similar restriction patterns between these gene sets suggested a high level of sequence homology. In fact, sequence analysis showed that a 2.2-kb region, including the entire large and small subunit structural genes, was totally conserved in rbcL1-rbcS1 and rbcL2-rbcS2. The rbcL1 (rbcL2) and rbcS1 (rbcS2) genes were 1,422 and 333 bp in length and encoded 473- and 110-amino-acid proteins, respectively. The genes were separated by a 90-bp spacer sequence and were preceded by possible ribosome-binding sites. The N-terminal amino acid sequences of the subunit proteins, synthesized in Escherichia coli, were determined by Edman degradation and found to agree with the deduced amino acid sequences, except for the N-terminal methionine residue. The transcriptional start site of the rbc genes was determined by primer extension, and the size of the rbc transcript was estimated to be about 2.1 kb, suggestive of the cotranscription of rbcL1-rbcS1 and/or rbcL2-rbcS2 mRNAs. Comparisons of amino acid sequences of both subunits with those of other organisms revealed that the ribulose-1,5-bisphosphate carboxylase of T. ferrooxidans, a chemoautotrophic bacterium, is phylogenetically closer to the photosynthetic bacterium Chromatium vinosum than to another chemoautotrophic bacterium, Alcaligenes eutrophus.

[Myelodysplasia predominantly involving in megakaryocytic lineage successfully treated with low-dose Ara-C]

A 17 year old male was admitted because of pancytopenia. Bone marrow aspiration revealed myelodysplasia, no increase of blast cells and excessive expansion of megakaryocytic lineage. Although mild increase of bone marrow reticulin fiber was observed, no hepatosplenomegaly was recognized. Therefore he was diagnosed as refractory anemia (RA) or MDS with myelofibrosis and treated with low dose Ara-C regimen. Remission was achieved in June 1987, but the relapse occurred in Oct. 1987. His bone marrow at the relapse showed more remarkable dysplastic change than before. Sequential bone marrow examinations thereafter, revealed an increase of megakaryocytic lineage, especially immature dysplastic megakaryocytes, leading to the appearance of the abnormal megakaryoblasts (detected with anti GP IIb/IIIa antibody) as well as uncharacterized blast cells in his terminal stage. Transformation from MDS to megakaryocytic leukemia was strongly suggested. He died of severe pneumonia in March 1989. The invasion of abnormal immature megakaryocytic cells including megakaryoblasts was observed in liver, spleen and lymph nodes at autopsy. There are several reports on cases having a common hematological features such as 1) pancytopenia in peripheral blood, 2) myelodysplasia, 3) excessive growth of megakaryocytic lineage, 4) myelofibrosis without hepatosplenomegaly, although other clinical features were different. We propose all these cases should be reviewed at the point of MDS mainly involved in megakaryocytic lineage.

[Sweet's syndrome with pregnancy]

A 31-year-old pregnant woman had eruptions on her wrist, face and neck. We diagnosed her as having Sweet's syndrome from clinical symptoms, histopathological and laboratory findings. We successfully treated her with prednisolone and there are no relapses after delivery. We studied her polymorphonuclear leukocyte activity by the polarization assay with N-formyl-methionyl-leucyl-phenylalanine as a chemoattractant and it is higher than that of control. It is known that Sweet's syndrome is accompanied with collagen diseases and malignant diseases or others as underlying diseases or conditions. Three cases of Sweet's syndrome associated with pregnancy have been reported before and this is the first one in Japan.