Japanese adults can learn to produce English /r/ and /l/ accurately

As is well known, Japanese adults who have just begun to learn English often err in producing /r/ and /l/ because their native language does not possess such liquid consonants. The aim of this study was to determine if Japanese adults eventually learn to produce /r/ and /l/ accurately in words like read and lead. Liquids spoken by 12 native Japanese speakers who had lived in the United States for an average of two years were often misidentified by native English-speaking listeners. Their productions of /r/ and /l/ also received much lower (and thus foreign-accented) ratings than did the native English speakers' liquids. On the other hand, liquids produced by native Japanese speakers who had lived in the United States for an average 21 years were identified correctly in forced-choice tests. This held true for liquids in words that had been read from a list as well as for words that had been spoken spontaneously. The ratings of liquids produced by 10 of the 12 experienced Japanese speakers fell within the range of ratings obtained for the 12 native English speakers. These findings challenge the widely accepted view that segmental production errors in a second language arise from the inevitable loss of ability to learn phonetic segments not found in the native language.

Signal detection modeling of Japanese listeners' /r/-/l/ labeling behavior in one-interval identification task

This study tested the validity of applying a signal detection model to Japanese listeners' /r/-/l/ labeling behavior in one-interval identification task, and the hypothesis that Japanese listeners estimate each token's goodness of fit to Japanese /r/ in labeling it as /r/ or /l/. The identification data obtained by manipulating subjects' response criteria fit the signal detection model. The performance in the identification task was highly predictable based on the goodness of fit judgment, indicating that category goodness information contained in /r/ and /l/ is utilized in deriving underlying sensory decision variables. The data, however, also suggested that these variables are not a direct consequence of the goodness of fit judgment. Various implications of the signal detection model in the investigation of Japanese perception of /r/ and /l/ are discussed.

Comparative mapping of the imprinted U2afbpL gene on mouse chromosome 11 and human chromosome 5

The genetic map location of the recently discovered imprinted gene U2afbpL has been verified and refined in several mouse crosses. RI strain analysis had previously shown that the gene is located on mouse chromosome 11. This assignment has been verified using interspecific backcrosses. Moreover, the location of the gene relative to a fixed order of markers in the proximal region of mouse chromosome 11 has been established. The location of the gene on mouse chromosome 11 corresponds to a homologous linkage group that is conserved on human chromosome 5q. The location of the human homologue has been determined using both somatic cell hybrid genetic analysis and fluorescence in situ hybridization. These analyses have mapped the human locus U2AFBPL to human chromosome 5q23-->q31.

Difference in excitation-contraction mechanisms between atrial and ventricular myocardia of hatched chicks

1. Effects of inotropic interventions on contractile force were examined in isolated atrial and ventricular preparations from hatched chicks. 2. The duration of twitch contractions were briefer in the atria than in the ventricle. 3. No difference in the extracellular Ca(2+)-contractile force curve was observed between atrial and ventricular preparations. 4. The sensitivity to nicardipine was higher in the ventricular preparations than in atrial preparations while that to ryanodine was higher in atrial preparations. 5. The magnitude of post-rest contraction was larger than the basal contractile force in atrial preparations, while it was smaller than the basal contractile force in ventricular preparations. 6. These results suggested that the atrial myocardium of hatched chick was more dependent on sarcoplasmic reticulum function than its ventricular myocardium, which is similar to the case with mammalian species.

Determination of tetrahydro-beta-carbolines in urine by high-performance liquid chromatography with suppression of artefact formation

A high-performance liquid chromatographic method has been developed for the determination of urinary tetrahydro-beta-carbolines. When standing tryptamine with formaldehyde and acetaldehyde under extraction conditions, the significant amounts of artefact 1,2,3,4-tetrahydro-beta-carboline (TBC) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) were formed in a short time. Urine samples added with 2-ethyl-1,2,3,4-tetrahydro-beta-carboline (an internal standard) were treated with fluorescamine, and then with glycine, followed by serial solvent extractions. Such a pretreatment using two-step reactions removed a precursor (trypamine) by extracting its fluorescamine derivative, and enhanced the detection response by consuming excess fluorescamine. It solved the analytical problem that artefact TBC and MTBC are formed during analysis. Reversed-phase ion-pair chromatography using a C8-column and trifluoroacetic acid as a counter ion completed a base-line separation of three analytes within 10 min. The calibration graphs showed a good linearity in the range 0.1-50.0 ng ml-1 of urine samples spiked with standard TBC and MTBC. In the spike experiment, the recovery and relative standard deviation were almost 100% and less than 3.0%, respectively, for both TBC and MTBC. The proposed method enables the determination of the genuine urinary concentrations of TBC and MTBC without involving their artefacts.

Anti-Candida activity of synthetic hydroxychalcones

The antifungal activity of different synthetic hydroxychalcones was determined against Candida species. It was revealed that the presence of hydroxyl groups at C-2, C-4, and C-2' in chalcone was essential to inhibit Candida growth. Among the chalcone derivatives examined, 2,4,2'-trihydroxy-5'-methylchalcone showed the most intensive anti-Candida activity, suggesting that it could be a potential therapeutic agent for candidosis.

Reconstruction of stenotic external auditory canal with a postauricular chondrocutaneous flap

A case of stenosis of the external auditory canal secondary to a burn injury was reconstructed with a chondrocutaneous postauricular flap. Advantages of this technique include the use of a single flap to reconstruct the whole circumference of the canal, the fact that a chondrocutaneous flap is more likely to prevent restenosis than a skin flap alone, and the fact that reconstruction with an axial-pattern flap is more reliable than reconstruction with a random-pattern flap.

[A case of Klippel-Trenaunay-Weber syndrome associated with intracranial multiple angiomas]

A case of Klippel-Trenaunay-Weber syndrome associated with multiple intracranial angiomas was reported. Intracranial angiomas with Klippel-Trenaunay-Weber syndrome is very rare. Only 4 cases are known to this day. A 24-year-old man fell at his workplace and suffered a head injury. He was admitted to our hospital. Neurological examination revealed no abnormality. However, physiological examination demonstrated hyperplasia and cutaneous hemangiomas of left lower leg, malformation of the left eyelid and clouding of the left cornea. CT showed left hemispheric atrophy and subdural effusion. MRI demonstrated multiple flow voids at the left cerebellar hemisphere and at pons. Cerebral angiogram demonstrated left cerebellar AVM and pontine angioma. Feeding arteries of the AVM were left superior cerebellar artery and left posterior inferior cerebellar artery. Those of the pontine angioma could not be identified. No spinal angiomas were revealed. While spinal angiomas associated with this syndrome are known, association of intracranial lesions are rare. Reported anomalies are angiomas, hemi-hypertrophy of skull and brain, carotid occlusion, megadolicoanomaly of the basilar artery, meningioma and glioma. Our case report with cerebral angiomas is the first one in Japan. We postulate that anomaly of our case originated at the Streeter's 2nd-3rd stage or that multiple anomalies occurred. We emphasize that intracranial, spinal or visceral angiomas, which can be fatal if it bleeds, should be routinely examined in Klippel-Trenaunay-Weber syndrome.

Hyperresponsiveness of cardiac muscles to histamine in reserpine-treated guinea pigs

The hyperresponsiveness of cardiac tissue to histamine following treatment with reserpine was pharmacologically characterized. Guinea pig hearts were isolated 24 hours after intraperitoneal administration of 5 mg/kg reserpine. This treatment resulted in a complete depletion of tissue norepinephrine. Reserpine treatment potentiated the positive inotropic response of isolated perfused hearts to histamine at doses ranging from 0.3 to 3 micrograms (23 to 57% increase for reserpine-treated animals vs. 14 to 32% increase for control animals). Isolated left ventricular papillary muscle of reserpine-treated guinea pig hearts also showed hyperresponsiveness to histamine at concentrations of 0.1 microM or greater. The hyperresponsiveness of the papillary muscle contraction of the reserpine-treated animals to histamine was abolished in the presence of 1 microM cimetidine, but not attenuated in the presence of 1 microM diphenhydramine. This hyperresponsiveness was not modified by 1 microM bunazosin or 1 microM propranolol. The results suggest that H2-receptor mediated action plays a role in the hyperresponsiveness of cardiac muscles to histamine.

Pharmacokinetic profiles of intravenous imipenem/cilastatin during slow hemodialysis in critically ill patients

The pharmacokinetics of imipenem/cilastatin were determined in 7 critically ill patients undergoing slow hemodialysis (HD). All patients were anuric. Following intravenous administration of 500 mg of imipenem/cilastatin, concentrations of the drugs in the serum and dialysate were monitored during slow HD. The elimination phase half-life of imipenem was 3.1 +/- 0.3 h and that of cilastatin was 9.7 +/- 1.2 h. The total body clearance of imipenem and cilastatin was 84.0 +/- 7.2 and 32.2 +/- 2.4 ml/min, respectively. Clearance of imipenem and cilastatin during slow HD was 24.3 +/- 2.4 and 54.3 +/- 3.1%, respectively, of total body clearance. After the 10.5-h session of slow HD, serum concentrations of imipenem and cilastatin were 2.3 +/- 0.4 and 16.0 +/- 1.2 mg/l, respectively. It appears that at least 500 mg of imipenem may be needed as a supplemental dose after a session of slow HD or the application interval should be shortened to maintain a therapeutic concentration.

Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials

Acrylic resin dentures have the potential to elicit irritation, inflammation, and an allergic response of the oral mucosa. Studies of substances leachable from acrylic resins, their cytotoxicity to cultured cells, and means of reducing their leaching were systematically conducted. Under in vivo and in vitro conditions, formaldehyde and methyl methacrylate were significantly leached into human saliva and saliva-substitute buffer, especially from autopolymerized resins. Both leachable substances showed cytotoxic potentials in the range of their leaching concentrations. Formaldehyde was cytotoxic at lower concentrations than methyl methacrylate. Preleaching in water reduced subsequent leaching of both formaldehyde and methyl methacrylate, and the amount of reduction depended on an increase in the preleaching temperatures. Immersion of acrylic resin dentures in hot water (50 degrees C) before insertion is recommended, especially for autopolymerized resins used either for rebasing or as denture base materials, to minimize the risk of adverse reactions in patients who wear acrylic resin dentures.

[Hemoperfusion and plasma exchange therapy in patients with paraquat poisoning]

In these past three years, we treated 5 patients who attempted suicide by taking paraquat, a herbicide that had been kept at home, by direct hemoperfusion (DHP) alone or in combination with double filtration plasmapheresis (DFPP) in addition to conservative therapy. DHP alone was performed on 3 patients, 2 of whom recovered. The other 1 patient treated by DHP alone and 2 treated by the combination therapy died. These patients showed a plasma paraquat concentration exceeding the survival curve presented by Proudfoot. In such patients, appropriate combinations among hemodialysis, hemofiltration, DHP, and DFPP may be safer and more effective than each therapy alone.

Effects of naftidrofuryl oxalate on microsphere-induced changes in acetylcholine and amino acid content of rat brain regions

Effects of naftidrofuryl oxalate (naftidrofuryl) on neurotransmitter, acetylcholine, and amino acid content of brain regions following microsphere-induced cerebral embolism were examined to elucidate its possible therapeutic effects on ischemic brain. Rats received 900 microspheres (48 microns in diameter) via the right internal carotid artery, followed by ligation of the right common carotid artery; and histological and biochemical alterations were examined on the 3rd, 5th, and 28th days after embolism. The embolism induced increases in triphenyltetrazolium chloride- (TTC)-unstained areas and decreases in acetylcholine, glutamate, aspartate, and gamma-aminobutyric acid (GABA) contents in the cerebral cortex, striatum, and hippocampus of the right hemisphere, suggesting that microsphere embolism causes severe damage to these brain regions. Hematoxylin-eosin staining of the right cortical sections after embolism showed degeneration and necrosis of nerve cells with chromatolytic nuclei and eosinophilic cytoplasm. Changes in neurotransmitters of the left hemisphere were relatively small. Treatment with naftidrofuryl of the embolized rats with stroke-like symptoms took place from postoperative day 1 to 28. Treatment resulted in a reduction in TTC-unstained areas, less morphological damage to cerebral cortex on the 3rd and 5th days, and an appreciable restoration of acetylcholine content of three brain regions of the right hemisphere throughout the experiment, but restoration of neurotransmitter amino acids was observed to a smaller degree. The results suggest that naftidrofuryl is capable of preventing the development of ischemia-induced, sustained damage to brain regions vulnerable to oxygen deficiency, particularly by improving impaired acetylcholine metabolism.

Effects of low sodium ouabain and amiloride on chick myocardial contraction

1. Effects of Ca2+, low Na+, ouabain and amiloride on contractile force were examined in myocardial preparations from embryonic and hatched chicks. Measurement of contractile force was performed in an organ bath with whole hearts for the young embryo (5-6 days old) and with isolated strips from the right ventricles for the old embryos (16-18-day-old), hatched chicks (within 24 hr after hatching) and 1-week-old chicks. 2. The maximum increase in contractile force above the basal value at each age was determined by increasing extracellular Ca2+, which was smaller in young embryonic hearts than in older ones. 3. Decreasing the Na+ concentration to half of the normal value increased the contractile force in all ages examined: the increase in contractile force expressed as a percentage of the maximum increase at each age was significantly larger in young embryonic hearts than in older ones. 4. Ouabain produced increases in contractile forces at all ages examined; the effective concentration was lower in young embryonic hearts than in older hearts. 5. Amiloride prolonged the relaxation phase of contraction at all ages examined; the degree of prolongation was larger in young embryonic hearts than in older ones. 6. The present results suggest that, in the chick myocardium, the relative role of Na(+)-Ca2+ exchange in relaxation decreases during embryonic development, which may reflect the concurrent increase in sarcoplasmic reticulum function [Tanaka, Takagi and Shigenobu (1993) J. Dev. Physiol. 19, 235-240.

Effects of naftidrofuryl oxalate on microsphere embolism-induced decrease in regional blood flow of rat brain

1. The purpose of the present study was to determine whether naftidrofuryl oxalate (naftidrofuryl), a vasodilator, is capable of improving brain regional blood flow of animals in sustained ischaemia. 2. Cerebral ischaemia was induced by injecting 900 microspheres (48 microns in diameter) into the right internal carotid artery of rats. Cerebral blood flow of brain regions was measured by a hydrogen clearance method on the 3rd, 7th and 28th days after the onset of ischaemia. Ischaemic animals were treated with naftidrofuryl, 15 mg kg-1 day-1 i.p., from the first to 28th day. 3. Microsphere-embolism caused a sustained decrease in cortical and striatal blood flow over a period of 28 days, whereas hippocampal blood flow was decreased on the 3rd day but not on the 7th or 28th day. On the 3rd day, the striatal and hippocampal but not cortical blood flow of naftidrofuryl-treated, microsphere-embolized rats was higher than untreated rats. On the 7th and 28th days, the cortical and striatal blood flow of the treated and untreated animals did not differ. 4. Brain slices from microsphere-embolized rats contained areas, which were not stained with triphenyltetrazolium chloride (TTC), to a similar degree on the 3rd, 7th and 28th days, indicating the genesis of cerebral infarction. TTC-unstained areas of microsphere-embolized rats that had received naftidrofuryl treatment were smaller than those of untreated rats on the 3rd and 7th days, but not on the 28th day. 5. The results suggest that naftidrofuryl improves cerebral circulation impaired by microsphere-induced ischaemia and this higher level of cerebral blood flow of the treated animal may account for the delayed development of cerebral infarction.

Clinical features of end-stage renal failure in patients with essential hypertension

The development and progress of renal deterioration in patients with essential hypertension administered antihypertensive therapy remain unclear. In this retrospective analysis, we divided 25 essential hypertension patients who eventually required hemodialysis (HD) from 1981 to 1990, into those with malignant essential hypertension (MEH) (N = 9) and those with benign essential hypertension (BEH) (N = 16), and analyzed the clinical features, the rate of renal deterioration, and outcome in each group. The patients with MEH were significantly younger, and had a shorter duration of hypertension than those with BEH. There were no significant differences between the two groups in urinary volume, cardiothoracic ratio, hematological findings or blood chemistry at the initiation of HD. However, blood pressure in the patients with MEH was significantly higher than that in the patients with BEH at that time despite antihypertensive treatment. There was also no significant difference between the groups in the slope of reciprocal creatinine. The latter was significantly correlated with the level of blood pressure and serum total cholesterol. Considering the outcome, all of the patients with MEH survived for 5 years. These results suggest that the more rapid progression of renal deterioration in the patients with essential hypertension might be related to the severity of hypertension and to lipid abnormalities during antihypertensive therapy.

Identification of adenosine A2 receptor-cAMP system in human aortic endothelial cells

The involvement of endothelial adenosine A2 receptor-cAMP system in A2 receptor-mediated vasodilation in human aortic endothelial cells (HAEC) was investigated. Reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of both A2a and A2b receptors mRNA in HAEC. In HAEC, YT-146 (selective A2 receptor-agonist) produced a dose-dependent increase of cAMP production. This increase was inhibited by theophylline. YT-146 also showed a vasodilatory action in isolated rat aorta. The removal of endothelium significantly attenuated this vasodilatory effect. Our results provide the first evidence for the expression of both subtypes of the A2a and A2b receptors which regulate cAMP production in human endothelial cells. The present results also suggest that A2 receptor-cAMP system was involved in the endothelium-dependent vasodilatory actions and may play important roles in regulating vascular functions of HAEC.

Quantitation of urinary 1,2,3,4-tetrahydro-beta-carboline and 1-methyl-1,2,3,4-tetrahydro-beta-carboline by high-performance liquid chromatography

A high-performance liquid chromatographic method was developed to quantify 1,2,3,4-tetrahydro-beta-carboline (TBC) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) in human urine. Urine samples with added internal standard were subjected to a reaction with fluorescamine and solvent extractions to remove the precursor tryptamine, which readily condenses with aldehydes in samples and reagents. Such a pretreatment completely suppressed the artifactual formation of TBC and MTBC during analytical procedures. The purified original tetrahydro-beta-carbolines and the internal standard were separated by reversed-phase ion-pair chromatography with fluorescent detection. Their simultaneous separation was automatically completed in a short time (< 12 min). Both TBC and MTBC were quantified at ng/mL concentrations. The quantitative results revealed a wide variation in urinary levels of TBC and MTBC, possibly indicating that their considerable amounts excreted in the urine originate from dietary sources.

Molecular mechanism of adipogenic activation of the angiotensinogen gene

Angiotensinogen gene expression is controlled in a tissue- and development-specific manner. Interestingly, the angiotensinogen gene is abundantly expressed in adipose tissues other than the liver, where it is mainly produced. We investigated the molecular mechanism of angiotensinogen gene expression in a 3T3-L1 preadipocyte-adipocyte system. Although angiotensinogen mRNA was barely detectable in preadipocytes, its levels increased significantly during differentiation. As a whole, the pattern of the change in transcriptional activity of the angiotensinogen promoter was similar to that of the angiotensinogen mRNA levels during adipogenic differentiation, indicating that the activation of the angiotensinogen promoter might be involved in the adipogenic differentiation-coupled gene expression. The proximal promoter region, from -96 to +22 of the transcriptional start site, was sufficient to confer adipogenic activation, and the proximal element from -96 to -52 of the transcriptional start site was necessary for this promoter stimulation. DNA-protein binding experiments showed that this proximal element specifically bound to a nuclear factor induced by adipogenic differentiation. These results suggest that the proximal promoter element from -96 to -52 plays a role in adipogenic activation of the angiotensinogen promoter.

DNA fingerprint analysis of Dahl-Iwai salt-sensitive rats (S) and salt-resistant rats (R)

Using DNA fingerprint analyses, extensive molecular heterogeneity has been found between spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY), suggesting a doubtful value of simply comparing these rats in the study of the pathogenesis of genetic hypertension. Therefore, we evaluated the genetic similarity between Dahl salt-sensitive and salt-resistant rats newly inbred by Dr.Iwai (Dahl-Iwai S and R rats), by use of DNA fingerprint analysis. Fingerprint patterns were generated by probing Hinf I- or Alu I-digested DNA with an oligonucleotide corresponded to the tandem repeat sequence of the human myoglobin 33.6 minisatellite. These fingerprint patterns were same within each strain. S and R rts shared 82 percent of the bands in Hinf I-digested DNA and 93 percent of those in Alu I-digested DNA. Although Dahl-Iwai S and R rats are more closely related than SHR and WKY rats, multiple genetic differences still exist between these Dahl strains.

Slow hemodialysis performed during the day in managing renal failure in critically ill patients

Slow hemodialysis (HD) was performed for 10 h during the day in 11 critically ill patients with renal failure. The dialysis method was a modification of the pump-driven continuous venovenous HD. A nonsterile bicarbonate-containing hemodialysate was passed into the EVAL membrane dialyzer at a flow rate of 30 ml/min. No patient developed further hemodynamic instability during the treatment. The serum urea level was maintained below 20 mmol/l within 4 days of initiating the treatment. It allowed the patients to rest without interruption at night. This method was safely conducted by general nursing staff under the supervision of nephrologists on duty during the day. This schedule offers an approach to renal replacement therapy for hemodynamically unstable patients without any potential problem in the extracorporeal circulation at night.

Telomere change and loss of heterozygosity of mouse primary tumors and cell lines

Changes in the number of telomere repeat arrays were examined in mouse tumor cells. Telomeres that function for the protection of chromosomes were detected as bands and a smear by pulsed field gel electrophoresis and gel-hybridization using (TTAGGG)4, as a probe. Of eight primary tumors induced in F1 mice between C57BL/6 and C3H/He and between C57BL/6 and MSM, three showed telomere alteration, two having extra bands and one having lost several telomere bands. The others exhibited patterns similar to those of normal tissues. However, the change was detected in all four cell lines that were established from one of the tumors. One cell line was further cloned and examined. Two of the nine clones differed in the telomere pattern. The telomere change was also observed in two other cell lines, FM3A cells and nontransformed BALB3T3 cells. These results suggest that telomeres are highly mutable in tumor cells and cultured cell lines. Three of the tumors and one cell line were analyzed for loss of heterozygosity with 51 microsatellite probes covering all 19 autosomes. Also, karyotype analysis of the cell line was performed. No allelic loss was seen and chromosomal abnormality was rare, although aneuploidy and imbalance in chromosomal number were observed. Possible involvement of the telomere changes observed here in chromosome impairment is discussed.

Effect of an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins

Effect of glazing with an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins was quantitatively evaluated. Disks prepared from auto-polymerized resins were painted with the material and radiated with ultraviolet light. The disks were immersed in artificial saliva and the concentrations of methyl methacrylate and formaldehyde leached were determined by high-performance liquid chromatography and flow injection analysis. Compared to untreated controls, the glaze significantly decreased concentrations of both leachable substances. Treatment with an ultraviolet light-activated coating material is effective in suppressing the leaching of methyl methacrylate and formaldehyde from acrylic resins as well as in smoothing the denture surfaces.

Cell fusion-induced quick change in replication time of the inactive mouse X chromosome: an implication for the maintenance mechanism of late replication

It is unknown how and why the genetically inactivated mammalian X chromosome replicates late in S phase. There are also occasional inactive X chromosomes characterized by an opposite behavior replicating early in S phase. Two clonal cell lines, MTLB3 and MTLH8, isolated from a cultured murine T-cell lymphoma have an allocyclic X chromosome of the latter type. This precociously replicating X chromosome was judged to be genetically inactive as the late replicating one. Immediately after fusion with another cell line, the precociously replicating X chromosome from these cells starts to replicate late in S phase. This finding seems to suggest that late replication characterizing the inactive X chromosome is actively maintained by a trans-acting factor in female somatic cells, and that its lack entails a switch from late replication to precocious replication. It remains unknown whether this presumptive factor also modifies the autosomal replication pattern.

X chromosome retains the memory of its parental origin in murine embryonic stem cells

A cytogenetic and biochemical study of balloon-like cystic embryoid bodies, formed by newly established embryonic stem (ES) cell lines having a cytogenetically or genetically marked X chromosome, revealed that the paternally derived X chromosome was inactivated in the majority of cells in the yolk sac-like mural region consisting of the visceral endoderm and mesoderm. The nonrandomness was less evident in the more solid polar region containing the ectodermal vesicle, mesoderm and visceral endoderm. Since the same was true in embryoid bodies derived from ES cells at the 30th subculture generation, it was concluded that the imprinting responsible for the preferential inactivation of the paternal X chromosome that was limited to non-epiblast cells of the female mouse embryos, was stably maintained in undifferentiated ES cells. Differentiating epiblast cells should be able to erase or avoid responding to the imprint.

Parental imprinting on the mouse X chromosome: effects on the early development of X0, XXY and XXX embryos

To examine the effects of X-chromosome imprinting during early mouse embryogenesis, we attempted to produce XM0, XP0, XMXMY, XMXPY and XMXMXP (where XM and XP stand for the maternally and the paternally derived X chromosome, respectively) making use of mouse strains bearing the translocation Rb(X.2)2Ad and the inversion In(X)1H. Unlike XMXPY embryos, XMXMY and XMXMXP conceptuses suffered from severe growth retardation or abnormal development characterized by deficient extra-embryonic structures at 6.5-7.5 days post coitum (dpc). A cytogenetic study suggested that two XM chromosomes remaining active in certain nonepiblast cells were responsible for the serious developmental abnormality found in these embryos disomic for XM. Although matings involving females heterozygous for Rb(X.2)Ad hinted at the paucity of XP0 embryos relative to those having the complementary karyotype of XMXMXP, further study of embryos from matings between females heterozygous for In(X)1H and Rb2Ad males did not substantiate this observation. Thus, the extensive peri-implantation loss of XP0 embryos shown by Hunt (1991) may be confined to X0 mothers. Taken together, this study failed to reveal a parentally imprinted X-linked gene essential for early mouse embryogenesis other than the one most probably corresponding to the X-chromosome inactivation centre.

[A case of type II cryoglobulinemia involving glomerulopathy associated with hepatitis C antibody]

We reported a case of type II cryoglobulinemia involving glomerulopathy associated with HCV-induced liver cirrhosis. The patient was a 57-year-old woman. Her past history included chronic hepatitis at 51 years and rheumatoid arthritis at 53 years of age. At 46 years, an erythematous lesion appeared on her legs, which was diagnosed as allergic vasculitis by skin biopsy. At 50 years, proteinuria, hematuria and hypertension were recognized. The next year, the first renal biopsy was performed and showed membranoproliferative glomerulonephritis (MPGN). Recently, the edema of her legs has progressed, and the laboratory data showed proteinuria, hematuria, hypocomplementemia, rheumatoid factor positivity, and increase of monoclonal IgG kappa chain. The second renal biopsy revealed an endocapillary proliferative glomerulonephritis-like lesion with marked infiltration of monocytes and macrophages. The subendothelial deposit showed a fine fibril-like pattern. She was treated with steroids and double filtration plasmapheresis (DFPP) therapy, but the treatment was not very effective. She died of liver cirrhosis, which was probably induced by hepatitis C virus (HCV), and sepsis. Generally, the patients of type II cryoglobulinemia often showed HCV antibody positivity, pointing to HCV as an etiological factor. In this case, renal biopsy was performed twice in the same patient, and the histologic findings suggest the clinicopathological course of cryoglobulinemia.

[Anaphylactoid reaction after intravenous administration of Gd-DTPA]

An anaphylactoid reaction due to Gd-DTPA was observed in a patient who had disposition of asthma bronchiale. Five minutes after injection of Gd-DTPA, the patient developed laryngeal edema and erythema over the whole body. The patient recovered after treatment. It may be advisable to tighten indications for Gd-DTPA study on patients with allergic disposition. Gd-DTPA should be used with the same care against the anaphylactoid reaction as iodinated contrast media.

Flow injection analysis of formaldehyde leached from denture-base acrylic resins

Formaldehyde is responsible for allergic inflammation in acrylic denture wearers and the quantitation of formaldehyde is necessary to study its leaching from denture-base materials. Flow injection analysis was developed to quantify the formaldehyde leached from acrylic resins. Different resins were immersed in aqueous solvents at 37 degrees C and the immersion solutions were directly injected into the flow system, in which formaldehyde was converted on-line to a fluorescent derivative and its fluorescence was detected. Under the optimized conditions, the leached formaldehyde could be quantified in a short time (within 4 min) with high sensitivity (pmol levels per injection) and high specificity (no fluorescent response to the other leachables). In leaching experiments, significant amounts of formaldehyde were leached from autopolymerized resins, but not from heat- and microwave-polymerized resins.

Sustained changes in acetylcholine and amino acid contents of brain regions following microsphere embolism in rats

The present study was undertaken to explore changes in neurotransmitters and neuromodulators of brain regions impaired by microsphere embolism-induced, sustained ischemia. Nine hundred microspheres (48 microns) were injected into the right internal carotid artery of rats, and the time course of changes in the triphenyltetrazolium chloride (TTC)-stained areas of their brain slices and acetylcholine and amino acid contents in the cerebral cortex, striatum and hippocampus of both hemispheres were determined. The TTC-unstained area, a measure of infarction, was developed in the right hemisphere by the 3rd day after the embolism, which was similar to that on the 28th day. A marked decline in acetylcholine content of these three regions of the right hemisphere was detected throughout the experiment (28 days). The glutamate, aspartate, GABA, and taurine levels were markedly decreased following microsphere-embolism. Most of these decreases were significantly attenuated during the first 5 days following the embolism, and they then partially recovered with time after the operation. Minor metabolic changes were observed in the left hemisphere. The results suggest that microsphere-embolism induces cerebral infarction and/or sustained damage to acetylcholine and neurotransmitter amino acid synthesis and/or catabolism of the brain regions. This model may provide information concerning the pathophysiological alterations in long-term cerebral ischemia and infarction.

Variable X chromosome inactivation patterns in near-tetraploid murine EC x somatic cell hybrid cells differentiated in vitro

For the cytogenetic study of X chromosome inactivation as an X chromosome dosage compensation mechanism, we isolated a number of XXXX, XXX, and XXY near-tetraploid mouse hybrid cell clones by fusing XX or XO embryonal carcinoma cells with lymphocytes carrying a structurally altered X chromosome(s). The inactive X chromosome from the female lymphocyte was reactivated in these hybrid clones which retained embryonal carcinoma morphology so far as they were cultured on the collagen-coated plastic surface in the medium supplemented with leukemia inhibitory factor (LIF) and betamercaptoethanol (BME). Some of these clones developed balloon-like cystic embryoid bodies when they were allowed to form cell aggregates in medium without LIF and BME in bacteriological petri dishes to which they do not adhere. X chromosome inactivation occurring during this process detected by the incorporation of 5-bromodeoxyuridine did not conform to the expected pattern leaving two X chromosomes active in every tetraploid cells. This may suggest either that the X-inactivation mechanism evolved primarily, for the diploid cell is unable to deal with tetraploid conditions efficiently, or that the present system of in vitro differentiation represents an anomalous situation never encountered in vivo.

Inotropic effects of ryanodine and calcium antagonists on embryonic and hatched chick myocardium

Effects of extracellular Ca2+ and inotropic agents on contractile force were examined in myocardial preparations from embryonic and hatched chicks. Measurement of contractile force was performed in an organ bath with whole hearts for the young embryo (5 to 6 days old) and with isolated strips from the right ventricles for the old embryos (16 to 18 days old), hatched chicks (within 24 hours after hatching) and 1 week old chicks. The extracellular Ca2+ concentration-contractile force curve was in a lower concentration range in young embryonic hearts when compared with older ones. 2 mM Ca2+ and 8 mM Ca2+ produced about 60% maximum contraction in preparations from young embryos and the older ages, respectively. The sensitivity to nicardipine and diltiazem was similar among all ages examined under 2 mM Ca2+. When the two drugs were applied to preparations from the older ages under 8 mM Ca2+, the sensitivity was lower than that of the young embryo under 2 mM Ca2+. Ryanodine produced a negative inotropic response at all ages but the effect was smaller in the young embryo when compared with those of older ages. Mn2+ produced a negative inotropic effect at all ages. In the older three ages, Mn2+ produced a late augmentation of the contractile force in addition to the initial negative inotropic response, while such augmentation was not observed in the young embryo. In conclusion, the chick myocardium was shown to undergo developmental changes in excitation-contraction mechanisms including increase in sarcoplasmic reticulum function during the embryonic period, and thus provides an interesting model for studies on excitation-contraction mechanisms.

Effects of naftidrofuryl oxalate on microsphere embolism-induced changes in tricarboxylic acid cycle intermediates of rats

The present study was undertaken to determine whether naftidrofuryl oxalate, a cerebral vasodilator, may improve or attenuate microsphere embolism-induced damage to the mitochondrial tricarboxylic acid cycle. For this purpose, the intermediates in the tricarboxylic acid cycle were determined using cerebral cortex isolated from microsphere-injected rats with and without naftidrofuryl oxalate treatment. Seven-hundred microspheres, with a diameter of 48 microns were injected into the right hemisphere through the right common carotid artery. The presence of cerebral infarction on the 3rd day after the operation was confirmed by the development of triphenyltetrazolium chloride-unstained areas in brain sections. Succinate, fumarate, malate, citrate and alpha-ketoglutarate, but not oxaloacetate, contents were significantly decreased in the right hemisphere of rats on the 3rd day following microsphere embolism. In the left hemisphere, a similar but smaller decrease in these intermediates was seen. The rats, which showed typical stroke-like symptoms, were treated with 15 mg/kg naftidrofuryl oxalate i.p., twice daily for 2.5 days, resulting in a significant reversal of the intermediate content of both hemispheres toward the control and an increased in the triphenyltetrazolium-stained area of a coronal section of the right hemisphere relative to the untreated animals. The results suggest that naftidrofuryl oxalate attenuates the development of microsphere embolism-induced cerebral infarction and improves microsphere-induced impairment of the mitochondrial tricarboxylic acid cycle. The observed effects provided evidence for a possible site of action of the agent on ischemic brain energy metabolism.

Application of 13C-labeling and nuclear magnetic resonance spectroscopy to pharmacokinetic research: measurement of metabolic rate of benzoic acid to hippuric acid in the rat

The use of 13C-labeling and nuclear magnetic resonance (NMR) spectroscopy to trace the biotransformation of benzoic acid (BA) to hippuric acid (HA) in the rat has been described. Novel [2,4,6,7-13C4]BA, which was labeled in the specific protonated carbons, was used in order to enhance the sensitivity of 13C NMR detection on the basis of the nuclear Overhauser enhancement and short spin-lattice relaxation time. The urinary excretion of [2,4,6,7-13C4]HA formed from intravenously administered [2,4,6,7-13C4]BA was followed by proton-decoupled 13C NMR spectroscopy (only 10 min accumulation time) without any separation procedures such as extraction and chromatography, using [2-13C]sodium acetate as an internal standard for quantitation. The heights of resonances for C2,6 of [2,4,6,7-13C4]HA and C2 of the internal standard were used to calculate [2,4,6,7-13C4]HA concentration. The lower limit of measurable amounts (ca. 40 nmol) was found to be improved about one order of magnitude over that of the method using commercially available [7-13C]BA. In general, this tracer technique has the potential for wide application to pharmacokinetic research since xenobiotic and endogenous metabolism can be followed by very simple and convenient procedures.

Identification and characterization of adenosine A1 receptor-cAMP system in human glomeruli

Although adenosine is known to affect renal function through stimulating adenosine receptors, little is known about A1 receptors in human glomeruli. Thus, we attempted to identify the adenosine A1 receptor-cyclic AMP (cAMP) system in human glomeruli. Normal renal cortical tissues were obtained at nephrectomy of patients with renal cell carcinoma. Glomeruli were isolated using a graded sieving method or dissected manually under a stereomicroscope. Radioligand binding assay using 2-chloro-N-[3H] cyclopentyl adenosine ([3H]CCPA, an A1 agonist ligand) was performed at 30 degrees C for 90 minutes. Cyclic AMP (cAMP) produced in glomeruli was measured after incubation with different concentrations of N6-cyclohexyladenosine (CHA; A1 agonist) and a phosphodiesterase inhibitor. The specific binding was saturated within 60 minutes and reversible by adding 1 mM of theophylline. Scatchard plot analysis revealed a single class of binding site (Kd = 1.78 +/- 0.21 nM, Bmax = 271.7 +/- 35.8 fmol/mg protein). The specific binding was inhibited dose-dependently by various agents in an order suggesting A1 receptor specificity. CHA inhibited the production of cAMP in microdissected human glomeruli. This inhibitory effect was antagonized by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; A1 antagonist). This is the first study revealing the presence of the A1 receptor-cAMP system in human glomeruli using a radioligand binding assay method and by measuring the cAMP production.

Aggressive rectal lymphoma of large granular lymphocytes with the histologic feature of an angiocentric growth pattern

The authors report an unusual large cell lymphoma of the rectum composed of large granular lymphocytes (LGL) with histologic characteristics of an angiocentric growth pattern. Immunophenotyping showed that most of the tumor cells were CD3-, CD4-, CD8+, CD16+, CD56+, and CD57-. Fine structural analysis of the tumor cells found substantial numbers of electron-dense granules. Genotypic investigation showed a germline configuration of the T-cell receptor beta and gamma chain genes and the immunoglobulin heavy chain gene. The clinical course was aggressive, with rapid dissemination to the lungs, liver, and subcutis. The lesion was resistant to chemotherapy. There was, however, no evidence for peripheral blood or bone marrow involvement. This case report demonstrates the need for continued inquiry into the possible association of LGL with angiocentric lymphoproliferative lesions and gut-associated T-lymphocyte lesions.

Remission induction of acute promyelocytic leukemia by all-trans-retinoic acid: molecular evidence of restoration of normal hematopoiesis after differentiation and subsequent extinction of leukemic clone

Sequential molecular and cellular changes during remission induction were investigated in a case of acute promyelocytic leukemia (APL) treated with all-trans-retinoic acid (ATRA). By means of clonality analysis, the assessment of the retinoic acid receptor alpha gene alterations, as well as conventional cytologic studies, it was demonstrated that remission induction of APL by ATRA proceeds in two steps: first, the differentiation of the leukemic clone to mature granulocytes and its subsequent extinction; second, proliferation/differentiation of the residual normal clones to restore polyclonal hematopoiesis.