Comparative study of the toxic effects of gallium arsenide, indium arsenide and arsenic trioxide following intratracheal instillations to the lung of Syrian golden hamsters

Toxic effects of gallium arsenide (GaAs), indium arsenide (InAs) and arsenic trioxide (As2O3) were studied in male Syrian golden hamsters. GaAs (7.7 mg/kg) and As2O3 (1.3 mg/kg) particles were instilled intratracheally twice a week a total of 16 times, while InAs (7.7 mg/kg) was instilled a total of 14 times. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During the instillation period, the cumulative body weight gain of the InAs-, but not the GaAs- or As2O3-treated hamsters was suppressed significantly, when compared with the control group. Slight to severe inflammatory responses were observed in the lung for all treatment groups. The most severe inflammatory change, characterized by an accumulation of neutrophils and macrophages, exudation, thickness of the pleura and fibrotic proliferation was found in the InAs-treated hamsters. Extensive alveolar or bronchiolar cell hyperplasia with or without keratinizing squamous cell metaplasia was observed in almost all the InAs-treated hamsters. Furthermore, squamous cell metaplasia or squamous cell hyperplasia developed in some of the InAs-treated hamsters, but not in the GaAs- or As2O3-treated hamsters. Slight to mild lesions were found in the convoluted tubules of the kidney in both the GaAs and InAs groups. From the present study, the toxic potency of these particles was provisionally estimated to be in the following order: InAs > GaAs > As2O3, at the dosage level used in this study. Furthermore, there was evidence that InAs particles could induce pulmonary, renal or systemic toxicity, and as such, InAs particles may produce pulmonary precancerous change when instilled intratracheally into hamsters.

Genetic mapping of the Camurati-Engelmann disease locus to chromosome 19q13.1-q13.3

Camurati-Engelmann disease (CED [MIM 131300]), or progressive diaphyseal dysplasia, is an autosomal dominant sclerosing bone dysplasia characterized by progressive bone formation along the periosteal and endosteal surfaces at the diaphyseal and metaphyseal regions of long bones and cranial hyperostosis, particularly at the skull base. The gene for CED, or its chromosomal localization, has not yet been identified. We performed a genomewide linkage analysis of two unrelated Japanese families with CED, in which a total of 27 members were available for this study; 16 of them were affected with the disease. Two-point linkage analysis revealed a maximum LOD score of 7.41 (recombination fraction.00; penetrance 1.00) for the D19S918 microsatellite marker locus. Haplotype analysis revealed that all the affected individuals shared a common haplotype observed, in each family, between D19S881 and D19S606, at chromosome 19q13.1-q13.3. These findings, together with a genetic distance among the marker loci, indicate that the CED locus can be assigned to a 15.1-cM segment between D19S881 and D19S606.

Kabuki make-up syndrome is not caused by microdeletion close to the van der Woude syndrome critical region at 1q32-q41

We reported on a 5-year-old Japanese girl with clinical manifestations of Kabuki make-up syndrome (KMS) and van der Woude syndrome (VWS). Since the concurrence of the two syndromes is known in four patients, including ours, it suggests a common cause. Assuming that the association of the two syndromes was caused by a microdeletion involving the putative KMS/VWS genes, we carried out fluorescence in situ hybridization and microsatellite analyses using PAC clones and dinucleotide repeat markers spanning the VWS1 critical region at 1q32-q41. No deletion was detected at the VWS1 critical region.

Frequency and prognostic value of cardiac troponin I elevation after coronary stenting

Mild myocardial injuries after coronary angioplasty are associated with adverse late outcomes. The incidence and prognostic value of this phenomenon when using cardiac troponin I (cTnI) after stent implantation is unknown. We studied cTnI and creatine kinase (CK) release in 109 patients after stenting. Clinical success was achieved in 103 patients (94%). In-hospital major adverse coronary events were: death in 1 patient, Q-wave myocardial infarction in 1 patient, and non-Q-wave myocardial infarction in 2 patients. Twenty-nine patients (27%) had postprocedural cTnI increase, 16 (15%) had CK elevation. No preprocedural variables predicted marker elevation. Marker release was related to the occurrence of in-lab complications (59% vs 29% [p = 0.004 for cTnI] and 69% vs 32% [p = 0.011 for CK]). In 34% no explanation was found for cTnI increase. Success was more frequent in patients without cTnI elevation (100% vs 86%, p <0.001). The negative predictive value of cTnI increase was 100% for in-hospital major adverse coronary events (MACE), whereas its positive predictive value was 14%. cTnI and CK concordant elevation was associated with more intra- and postprocedural adverse events. During a mean follow-up of 8+/-3 months, major adverse coronary events were: death in 2 patients, myocardial infarction in 2 patients, and repeat PTCA in 8 patients. cTnI elevation was not predictive of these late MACE. cTnI elevation is common after stenting, and is related to the occurrence of in-lab complications. Its isolated elevation is not a good predictor of MACE. Patients with concordant cTnI and CK elevation seem to be at higher risk of in-hospital MACE.

A case of spinocerebellar ataxia type 6 mimicking olivopontocerebellar atrophy

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant, slowly progressive cerebellar ataxia without multisystem involvement. We report a 57-year-old woman with genetically confirmed SCA6 who showed clinical features of olivopontocerebellar atrophy. Conventional T2-weighted and FLAIR MRI demonstrated high signal in the middle cerebellar peduncles, in addition to mild atrophy of the pons and cerebellum.

Relationship between polymorphism in the angiotensinogen, angiotensin-converting enzyme or angiotensin II receptor and renal progression in Japanese NIDDM patients

We determined the relationship between the gene polymorphism of angiotensinogen (AGT), angiotensin-converting enzyme (ACE), or angiotensin II receptor (AT1R) and the progression of diabetic nephropathy in a multicenter trial of ethnically homogeneous Japanese patients with non-insulin-dependent diabetes (NIDDM). Gene polymorphism of ACE I/D, AGT M235T and AT1R A1166C was determined by polymerase chain reaction amplification using allele-specific primers. Japanese NIDDM patients (n = 1,152) were selected from several diabetic clinics. All patients were divided into three groups as follows: (1) group I (n = 407): normoalbuminuric patients; (2) group II (n = 327): microalbuminuric patients, and (3) group III (n = 418): overt albuminuric patients. Clinical factors for investigation in all patients were the date of birth, gender, levels of urinary albumin excretion, findings of the ocular fundus, duration of diabetes, hemoglobin A1c and blood pressure. It appears that genetic polymorphisms in the renin-angiotensin systems, i.e. ACE or AT1R, may affect the progression to renal failure of patients (especially females) with NIDDM.

Cloning of translocation breakpoints associated with Shwachman syndrome and identification of a candidate gene

Shwachman syndrome is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency, bone-marrow dysfunction, and metaphyseal chondrodysplasia. A de novo balanced translocation was recently documented in a patient with this disease. Toward isolating the gene(s) responsible for Shwachman syndrome, we cloned and sequenced the translocation breakpoints in the DNA of this patient. The nucleotide sequences around the breakpoints contained neither repetitive elements nor motifs reported to be implicated in recombination events, although we did detect gains or losses of oligonucleotides at the translocation junctions. By large-scale genomic sequencing and in silico gene trapping, we identified two novel transcripts in the vicinity of the breakpoints that might represent candidate genes for Shwachman syndrome, one on chromosome 6 and the other on chromosome 12. The gene on chromosome 12 was actually disrupted by the translocation.

[A case of the cerebellar atrophy and pseudo-hyperchloremia as a clue to diagnose chronic bromvalerylurea intoxication]

A 36-year-old woman was admitted to our hospital because of walking disturbance and dizziness. Her neurological examination showed psychiatric disturbance, truncal and limb ataxia, wide-based gait. She has taken 3 g of bromvalerylurea daily. The laboratory test revealed elevated levels of serum chloride (201 mEq/L) and bromide (105 mg/dl), and decreased (-43 mEq/L) anion gap. Brain MRI revealed atrophy of upper part of the vermis and cerebellar hemisphere, and widening of the primary fissure and dilatation of the forth ventricle. Bromvalerylurea, which is an easily available sedative, should be still noted as a cause of cerebellar ataxia. Increased level of serum chloride was useful information for early diagnosis of chronic bromide intoxication.

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, and testosterone secretion before the onset of male puberty

To investigate hormonal change before the onset of male puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone hourly for 24 h. Forty-six boys (32 prepubertal and 14 pubertal) of short stature, between 4.4-19.3 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone was measured using high sensitivity RIA capable of detecting a testosterone concentration of 0.01 ng/mL. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 4-5 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated at early morning in all subjects. Mean 24-h LH, FSH, and testosterone concentrations of prepubertal subjects who did not attain puberty for at least 3 yr were 0.10 U/L, 0.63 U/L, and 0.06 ng/mL, respectively, whereas those of prepubertal subjects who attained puberty within 1 yr (0.54 U/L, 1.68 U/L, and 0.10 ng/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, and testosterone concentrations increased with developing puberty. All of the 46 subjects showed positive cross-correlation between the LH and testosterone time series. The mean lag time from the LH to the testosterone time series in the prepubertal subjects who attained puberty within 1 yr (4.7 +/- 2.4 h, mean +/- SD) was shorter than that in the prepubertal subjects who attained puberty after at least 3 yr (7.3 +/- 2.2 h). This lag time decreased with developing puberty, plateauing at 1.4 +/- 0.9 h at midpuberty. Thus, the diurnal rhythms of LH, FSH, and testosterone already exist at 4-5 yr of age; serum LH, FSH, and testosterone levels increase before the onset of puberty; and a time delay is observed between the LH and testosterone time series that decreases before the onset of puberty.

Expression of cysteine proteinases and their inhibitor, cystatin beta, in cultured rat mesangial cells

Matrix expansion in the glomerular mesangial area is observed in diabetic nephropathy. Intracellular breakdown of long-lived proteins was lower in mesangial cells in the high glucose medium than that in the control medium. Enzymatic activity of cathepsin L increased 1.4-fold after 6 h of treatment with the high glucose, and then declined gradually to 72% of control cells after treatment for 36 h. Change in the enzyme activity of cathepsin B showed a similar time course but less magnitude than that of cathepsin L. Immunoblot analysis with anti-cathepsin L antibody showed that change in the enzyme activity of cathepsin L was due to the change in the amount of cathepsin L, and that with anti-cathepsin B antibody showed no change in the amount of cathepsin B in the mesangial cells treated with high glucose. Intracellular cathepsin activities were controlled not only by the amounts but also by the inhibitor cystatin beta. Immunoblot analysis with anti-cystatin beta antibody showed that intracellular levels of cystatin beta increased slightly after 24 h of treatment with high glucose. These changes were derived from changes in mRNA level. These results, therefore, demonstrated that the decrease of intracellular protein breakdown in mesangial cells treated with high glucose medium was due to both suppression of cathepsins and increase of cystatin beta.

Dissociated expression of collagen type IV subchains in diabetic kidneys of KKAy mice

Diabetic nephropathy is characterized by thickening of the glomerular basement membrane and expansion of the mesangial matrix. The glomerular basement membrane is assembled from at least five genetically distinct collagen IV chains. In patients with diabetic nephropathy, differential distribution of these components has been demonstrated. In order to clarify the relationship between progression of diabetic nephropathy and altered type IV collagen assembly in the renal cortex, we examined steady state mRNA levels encoding collagen IV subchains in the kidney cortices of spontaneously diabetic KKAy mice and nondiabetic C57black mice as controls. They were sacrificed at 4, 8, 16, and 24 weeks of age. Northern and dot blot analyses were performed using 32P-labeled mouse probes for classical alpha1(IV) and alpha2(IV) and for alpha3(IV), alpha4(IV), and alpha5(IV) minor chains. The mRNA levels for all collagen IV chains peaked at 4 weeks of age and declined rapidly thereafter in the nondiabetic mice. At all times, alpha1(IV) and alpha2(IV) mRNA expressions were abundant and almost unchanged in KKAy mice. In contrast, mRNA levels for alpha3(IV), alpha4(IV), and alpha5(IV) progressively changed with age. It appears that the expression of minor collagen IV chains is dissociated from the alpha1(IV) and alpha2(IV) chains in diabetic nephropathy. Moreover, an unbalanced increase in the production may affect collagen IV assembly and contribute to basement membrane thickening in diabetic nephropathy of KKAy mice.

Immunohistochemical localization of microcystin-LR in the liver of mice: a study on the pathogenesis of microcystin-LR-induced hepatotoxicity

The relationship between the intralobular sites of hepatotoxic injury and the distribution of microcystin-LR (MCLR), an inhibitor of protein phosphatases 1 (PP1) and 2A (PP2A), was examined using an immunohistochemical method with a monoclonal antibody specific to MCLR on the livers of mice receiving a single i.p. injection of the MCLR. Immunoblotting and high-performance liquid chromatography analyses of liver extracts were also performed to determine the binding form of MCLR to PP1 and PP2A (MCLR-PP1/PP2A adducts) and free MCLR. Immunohistochemistry revealed a discernible intensity of staining in the centrilobular regions where hemorrhage and apoptosis occurred. In these regions, immunopositivity was evident in the cytoplasm and nuclei of the hepatocytes; some apoptotic cells were also immunopositive. In contrast, coagulative necrosis, which was mainly evident in the midlobular regions, was completely negative. Analysis of liver extracts demonstrated MCLR-PP1/PP2A adducts, but free MCLR was below detection limit. These results suggest that the immunohistochemical localization of MCLR in centrilobular hepatocytes is closely associated with the onset of hemorrhage and apoptosis and is related to adduct formation. The occurrence of coagulative necrosis however might also be related to other factors such as ischemia/hypoxia.

The nucleotide sequence of the coat protein genes of satsuma dwarf virus and naval orange infectious mottling virus

The sequence of the 3'-terminal 4320 and 2409 nucleotides were determined for RNA2 of satsuma dwarf virus (SDV) and navel infectious mottling virus (NIMV). Both sequences contained a part of a long open reading frame which encodes larger and smaller coat proteins (CPs) at the 3'-terminus followed by a 3'non-coding region upstream of a poly (A) tail. Amino acid sequence identity for larger and smaller CPs ranged 81-84% and 68-78%, respectively, among SDV, NIMV and the previously sequenced citrus mosaic virus (CiMV). No significant sequence similarity was found between the CPs of SDV or NIMV and those of the como-, nepo- or other viruses. The nucleotide sequence identity of the 3' non-coding region of RNA2 were 68%-78% among SDV, CiMV and NIMV. These results suggest that SDV, CiMV and NIMV are distinct, though related, viruses. They may be assigned as members of the new genus, which is close to the genera of Comovirus and Nepovirus.

Antegrade transseptal coronary angiography: an alternative technique in severe vascular disease

We report the case of a patient with severe vascular disease in whom retrograde access to the aortic root was not possible because of aortoiliac and axillary vascular disease. Antegrade coronary angiography was performed through the transseptal approach using standard catheters, although several technical difficulties were encountered.

Clinical characteristics of children with hypoparathyroidism due to 22q11.2 microdeletion

The phenotypes of chromosomal 22q11.2 microdeletion are quite variable among individuals and hypoparathyroidism (HP) constitutes a definite portion of the clinical spectrum. For the correct diagnosis and pertinent follow up of the HP children due to del22q11.2, we tried to delineate the clinical characteristics of such patients. By employing fluorescence in situ hybridization (FISH) to all the patients diagnosed as HP in our clinic, ten possessed the 22q11.2 microdeletion. Among them, the incidence of cardiac defect (5/10), recurrent infection (1/10) and cleft palate (1/10) was modest. Additionally, seven of them had been diagnosed as HP during the infantile period, when their facial abnormality and intellectual problem had not become evident. Notably, two patients were complicated by Graves disease, while the association of idiopathic thrombocytopenic purpura was also observed in two girls.

CONCLUSION

HP due to del22q11.2 may be misdiagnosed as idiopathic, especially in an infant who lacks apparent complications like cardiac anomaly. They should be closely followed up for auto-immune complications.

L1CAM mutation in a Japanese family with X-linked hydrocephalus: a study for genetic counseling

Mutations in the gene encoding neural cell adhesion molecule L1 (L1CAM) are involved in X-linked hydrocephalus (HSAS, hydrocephalus due to stenosis of the aqueduct of Sylvius), MASA syndrome (mental retardation, aphasia, shuffling gait, and adducted thumbs), and spastic paraplegia type 1. We examined the L1CAM mutation in a Japanese family with HSAS for the purpose of DNA-based genetic counseling. The proband was a 9-year-old boy who had a 1-bp deletion in exon 22 of the L1CAM gene. This resulted in a shift of the reading frame, and introduction of a premature stop codon. Translation of this mRNA will create a truncated protein without the transmembrane domain, which cannot be expressed on the cell surface. Magnetic resonance images (MRI) revealed markedly enlarged lateral ventricles, hypoplastic white matter, thin cortical mantle, agenesis of the corpus callosum and septum pellucidum, and a fused thalamus. These findings represented impaired L1CAM function during development of the nervous system with resultant adhesion between neurons, neurites outgrowth and fasciculation, and neural cell migration. Screening by Apa I digestion of polymerase chain reaction (PCR) products identified the mother and the younger sister as heterozygous carriers. The carriers were asymptomatic. The father and the other sister did not have the mutation. The identification of L1CAM mutation in families with HSAS will give them the opportunity for DNA-based counseling and prenatal diagnosis.

The effects of 20 days bed rest on serum lipids and lipoprotein concentrations in healthy young subjects

The effects of 20 days bed rest (BR) on serum lipids and lipoprotein concentrations were investigated in 23 healthy young subjects (13 males and 10 females, aged 19 to 25 yr.). After 20 days BR, VO2max was reduced in both genders, but body composition did not change. The ratio of glucose area to insulin area during an oral glucose tolerance test decreased gradually throughout BR, which suggested a decrease in insulin sensitivity. Estimated changes in plasma volume from the beginning of BR were largest at day 3 of BR (-9.1% in females and -3.4% in males) and seemed to return the initial level at the end of BR in both genders. The increase in serum triglycerides and the decrease in high density lipoprotein (HDL) cholesterol, and apolipoprotein AI were observed in both genders during BR. In a smaller study of 4 males and 5 females, 20 days BR was associated with a decrease in HDL, cholesterol, a decrease in apolipoprotein AI and apolipoprotein AII, decrease in a plasma postheparin lipoprotein lipase activity and an increase in very low density lipoprotein triglyceride. Overall, the data suggested that the decrease in lipoprotein lipase activity and insulin sensitivity may contribute to the impairment in HDL metabolism.

Acute oral toxicity of microcystin-LR, a cyanobacterial hepatotoxin, in mice

Microcystin-LR (MCLR) is a hepatotoxic peptide produced by Microcystis aeruginosa, an alga found worldwide in reservoirs for drinking supply; however, acute oral toxicity of purified MCLR remains unknown. Therefore, a single dose of MCLR (more than 95% purity) ranging from 8.0 to 20.0 mg/kg body weight was orally given to female 6-week old BALB/c mice, and lethality and pathological changes were observed. Median lethal dose (LD50) of the orally given MCLR estimated by the up and down method was 10.9 mg/kg, which was 167 times higher than the i.p. LD50 value (65.4 microgram/kg by moving average method). Orally administrated toxin caused primarily hepatocellular injuries with characteristics of hemorrhage and necrosis. In situ end-labeling as well as electron microscopic observation revealed an induction of apoptotic cell death to hepatocytes. These results indicate the lethality of MCLR was much lower in oral dosage than by i.p. administration, but toxic effects are similar. In addition, apoptosis is considered one of major components in MCLR-induced hepatotoxicity.