Missense mutations affecting a conserved cysteine pair in the TH domain of Btk

Tec family protein tyrosine kinases have in their N-terminus two domains. The PH domain is followed by Tec homology (TH) domain, which consists of two motifs. The first pattern, Btk motif, is also present in some Ras GAP molecules. C-terminal half of the TH domain, a proline-rich region, has been shown to bind to SH3 domains. Mutations in Bruton's tyrosine kinase (Btk) belonging to the Tec family cause X-linked agammaglobulinemia (XLA) due to developmental arrest of B cells. Here we present the first missense mutations in the TH domain. The substitutions affect a conserved pair of cysteines, residues 154 and 155, involved in Zn2+ binding and thereby the mutations alter protein folding and stability.

A new mitochondrial DNA mutation associated with mitochondrial myopathy: tRNA(Leu)(UUR) 3254C-to-G

We investigated a patient with mitochondrial myopathy accompanied by cardiomyopathy. Molecular analysis disclosed a C-to-G substitution at nucleotide position 3254 of the mitochondrial tRNA(Leu)(UUR). Pedigree analysis revealed that this mutation was inherited maternally. Mutation C3254G may also be a candidate for genetic defects in mitochondrial myopathy.

Possible existence of platelet aggregation inhibitor(s) in a gas-phase extract of cigarette smoke

Present study demonstrated an existence of anti-aggregation factor(s) in water-soluble extract of a gas-phase of cigarette smoke, and studied chemical characteristics of the factor(s) evaluating its inhibitory potency on platelet aggregation of human and rabbit platelets. The water-soluble extract was prepared by passing mainstream smoke of one cigarette through a Cambridge glassfiber filter and then bubbling it through 1 ml of water. The inhibitory effects were similar in both human and rabbit platelets with the final concentrations of 1 to 5% of the aqueous extract, and were also non-specific irrespective of types of agonists such as collagen, arachidonic acid, STA2 (a stable analogue of thromboxane A2), ADP or nor-adrenaline. The inhibitory effect of water-soluble extract on platelet aggregation were not affected by treatment of the extract by erythrocytes, indicating that the factor(s) was different from the one that is adsorbed by hemoglobin, such as superoxide radicals, nitric oxide (NO), nitrogen oxides (Nox), hydrogen peroxide (H2O2), carbon monoxide (CO), aldehydes, trace elements (Cd2+, Cu2+) or carcinogenic nitrosocompounds. The inhibitor(s) was stable in acidic condition under 4 degrees C but unstable in basic condition under room temperature. The anti-platelet factor(s) was retained on a reversed phase chromatography column, and eluted with 50 to 60% methanol. The substance(s) was also adsorbed by H+ and OH- form ion exchange columns, but not by Cl- form, suggesting that the substance is both basic and acidic but not so strong as to be absorbed by Cl- form column. These facts suggest that the anti-platelet substance(s) in the water extract of cigarette smoke seems to be moderately non polar, both acidic and basic in water and not adsorbed by hemoglobin.

[Chronic neuropathy, a high level of protein in cerebrospinal fluid, and vitamin B1 and folate deficiency in a patient with normal-pressure hydrocephalus]

A 67-year-old woman presented with a 1-year history of gradual weight loss, reduced mental activity, muscle weakness, and urinary dysfunction. Neurological examination revealed mild lethargy, severe muscular atrophy, and diminished deep tendon reflexes in the extremities. The levels of vitamin B1 and folate in blood were low: 1.9 micrograms/dl (normal range 2.0-7.2) and 0.7 ng/ml (normal range 4.0-12.0). respectively. A lumbar puncture was done. The pressure of the cerebrospinal fluid was within normal limits, the level of protein was very high (467 mg/dl), and only a few lymphocytes were seen. A nerve-conduction study showed low amplitudes of action potentials and slow conduction velocities in both the motor and sensory nerves. Myelin irregularity, "onion bulb formation", and axonal atrophy were seen in a specimen obtained by sural nerve biopsy. A T2-weighted magnetic resonance image of the brain showed ventricular dilatation, high-intensity signals around the lateral ventricles, and a flow-void sign of the cerebral aqueduct. Radioisotope cisternography (111In-DTPA) disclosed ventricular reflux and slow clearance of the tracer from the ventricles. These findings indicated the presence of chronic inflammatory demyelinating polyneuropathy, nutritional polyneuropathy, vitamin B1 deficiency, folate deficiency, and normal pressure hydrocephalus. In this patient, the high level of protein in the cerebrospinal fluid may have caused the hydrocephalus.

[Antigenic epitopes recognized by autoantibodies to calpastatin in patients with rheumatoid arthritis and their clinical significance]

We have previously described that novel autoantibodies to calpastatin (endogenous inhibitor for calcium-dependent neutral protease, calpain) were detected in patients with rheumatoid arthritis (RA) and other disorders. Since calpain is thought to mediate inflammatory process and cartilage destruction, autoantibodies to its inhibitor protein, calpastatin, may be involved in the pathogenic mechanism of rheumatoid arthritis. In the present study, we analyzed antigenic epitopes reactive with autoantibodies to calpastatin and their clinical correlation. cDNA encoding the C-terminal 178 amino acids of human calpastatin (RA-6) was digested by restriction enzymes and ligated in to pEX expression vectors. These recombinant plasmids were tranfected into E. coli POP2136 and screened by colony blots using RA sera containing anticalpastatin antibodies and a mouse monoclonal antibody. RA patient sera recognized the C-terminus of domain IV (epitope C1 ; aa. 647-673) and C-terminus of domain III (epitope C2 ; aa. 496-571), whereas the mouse monoclonal antibody recognized an entirely different region containing the calpain-binding site (epitope B2 ; aa. 572-625). To evaluate epitope reactivity of patient autoantibodies, 15 RA sera containing anti-calpastatin were reacted with epitope fusion proteins. In immunoblotting, most RA sera recognized either C1 or C2 epitopes (67% and 40%, respectively), and only one patient recognized both epitopes. B2 epitope a more progressed and sever state of arthritis than those not reacting with C1. These results suggests that anti-calpastatin antibodies may play a role in the pathogenic mechanisms of RA and their epitope reactivity may be important for disease progression.

[Sjögren's syndrome with presenting as aseptic meningoencephaloradiculopathy in an elderly woman]

A 76-year-old woman was found to have acute aseptic meningoencephalitis with meningial irritation, disturbance of consciousness, elevation of cell counts in cerebrospinal fluid, and swelling of a right temporal-lobe lesion on a CT scan of the head. Muscle weakness in the lower extremities and urinary dysfunction developed and progressed gradually. The protein content of cerebrospinal fluid was high, and the distal latencies of F waves were prolonged, which suggested that the inflammation extended to the nerve roots. Sjögren's syndrome was diagnosed on the basis of atrophy of the labial salivary glands; invasions of lymphocytes and plasma cells to the intercellular space; and elevation of the titers of serum antinuclear antibody, anti-SS-A antibody, and anti-SS-B antibody. The patient had no xerosis. Aseptic meningoencephalitis was the first manifestation of Sjögren's syndrome. In recent years, several cases in which Sjögren's syndrome was associated with aseptic meningitis have been reported. However, we know of no previous report of such a case in a patient of this age. Aseptic meningoencephalitis can be the first manifestation of Sjögren's syndrome.

[A case of vitamin B12 deficiency with broad neurologic disorders and canities]

The patient was a 48-year-old woman with gait disturbance as her initial symptom. Two years after the onset of the gait disturbance, she developed motor weakness and a sensory disturbance in her limbs, and dementia. On admission to our hospital, the patient's serum vitamin B12 and folic acid levels were low, and she was found to have normochromic anemia. She also had widespread coarse hair and canities was diagnosed. The patient's paresthesia resolved in response to injection of 500 micrograms mecobalamin every other day, and the Hasegawa dementia scale score and the patient's hand grip strength improved. Her gait also improved, and she became able to walk on tiptoe. Her hair returned to normal. Supplementation with high-dose methyl B12 appeared to be effective to some extent in treating a broad range of neurologic disorders besides subacute combined degeneration of the spinal cord. In addition, the hair abnormality may be a marker of vitamin B12 deficiency.

Growth and behavioral changes in mice prenatally exposed to methylmercury and heat

Postnatal and behavioral changes in mice exposed prenatally to methylmercury and heat were investigated. Pregnant ICR mice were immersed in water at 37 degrees C or 42 degrees C for 10 min once or twice daily from day 12 through day 15 of gestation. Two hours after the heat exposure on day 12 of age, mice were injected s.c. with 5 mg Hg/kg of methylmercury (MeHg, as chloride) or saline. Prenatal exposure to heat significantly induced inactivity in an open field test (OPF) in males and retarded walking ability in both males and females. Prenatal exposure to MeHg caused significant inactivity in the OPF in females. Although heat did not enhance the effect of MeHg on physical growth or the behavior of pups and vice versa, there were some interactions between the effects of these two agents. Thus, the difference in walking ability in both sexes caused by heat was more distinctive in the saline-treated groups than in the MeHg-treated groups; the difference in locomotion in OPF caused by MeHg in females was more distinctive in the normothermic group than among the hyperthermic groups. The mechanisms underlying these behavioral changes need to be further examined.

Reproductive effects of prenatal exposure to 5-bromo-2'-deoxyuridine on male rats

5-Bromo-2'-deoxyuridine (BrdU) was administered intraperitoneally to Sprague-Dawley rats at doses of 12.5, 25, 50, or 100 mg/kg/d on days 9 through 15 of gestation, and at 50 or 100 mg/kg/d on days 16 through 20 of gestation. Dams were allowed to deliver naturally and the numbers of live and dead pups were recorded. Male offspring were allowed to mature and then cohabited with untreated female rats for assessment of reproductive performance. Dam body weight gain during pregnancy and lactation periods was not reduced by the treatment with BrdU. Dams treated with 50 and 100 mg BrdU/kg on days 9 through 15 of gestation had litters with decreased survival rates. The male offspring from dams treated with 25, 50, and 100 mg BrdU/kg on days 9 through 15 of gestation had reduced body weights over the course of the entire study. A dose-related decrease in copulation and fertility rates was found in the male offspring of dams treated on days 9 through 15 of gestation, while no significant decrease in those rates were found in the male offspring of dams treated on days 16 through 20 of gestation. Neither histopathologic examination of testes nor sperm examination indicated the cause of the impaired fertility in the male offspring from dams treated with BrdU on days 9 through 15 of gestation. All of the male offspring of dams treated with 100 mg BrdU/kg on days 9 through 15 of gestation failed to copulate, and some of the male offspring of dams treated with 50 mg BrdU/kg on days 9 through 15 of gestation did not form copulatory plugs or formed very small plugs. Dilatation of the lateral ventricles and cysts in the pars distalis of the pituitary were observed in all of the male offspring of dams treated with 100 mg BrdU/kg on days 9 through 15 of gestation. The impaired fertility of the male offspring of dams treated prenatally with BrdU may have resulted from BrdU exposure effects on central nervous system action such as loss of libido and from failure to form proper copulatory plugs, rather than the direct effects of BrdU on the male reproductive organs.

Pathologic implications of restored positive T waves and persistent negative T waves after Q wave myocardial infarction

OBJECTIVES

We sought to study the pathologic implications of restored positive T waves and persistent negative T waves in the chronic stage of Q wave myocardial infarction.

BACKGROUND

Some inverted T waves (coronary T waves) become positive after acute myocardial infarction; others retain their negative T wave component for a long time. The pathologic implications of the difference between restored positive T waves and persistent negative T waves in leads with Q waves has not, until now, been given much careful study.

METHODS

Of 17 patients with anterior or anteroseptal myocardial infarction confirmed by autopsy, 8 (group P) had positive and 9 (group N) had negative T waves in precordial leads with Q waves > or = 1 year after the onset of myocardial infarction. The appearance and extent of the infarct area and the degree of coronary artery stenosis were evaluated in both groups.

RESULTS

At autopsy, seven of eight patients in group P had nontransmural fibrotic changes in the anteroseptal or anterior wall. However, seven of nine patients in group N had a transmural myocardial infarction consisting of only a thin fibrotic layer in the anteroseptal or anterior wall. The left anterior descending coronary artery showed 75% stenosis in 1 patient in each group but > 90% stenosis in the remaining 15 patients.

CONCLUSIONS

Persistent negative T waves in leads with Q waves in the chronic stage of myocardial infarction indicate the presence of a transmural infarction with a thin fibrotic layer, whereas positive T waves indicate a nontransmural infarct containing viable myocardium within the layer.

Salivary duct carcinoma: a clinicopathologic study of three cases with a review of the literature

Three cases of salivary duct carcinoma are presented. They occurred in a 60 year old man, a 66 year old man and a 57 year old woman. All of the lesions were located in the parotid gland. The tumor size ranged from 3 to 5 cm across the largest diameter. Facial paralysis was observed in two cases. Histologically, intraductal and invasive adenocarcinoma showing papillary, cribriform, and solid patterns with comedolike necrosis was observed. Immunohistochemically, the tumor cells were positive for keratin and epithelial membrane antigen. No myoepithelial cells were demonstrated within the tumor by staining for S-100 protein, alpha-smooth muscle actin or muscle specific actin. Ultrastructurally, intracytoplasmic lumina with microvilli, a moderate number of mitochrondria, lysosomes, and tight junctions were found. Regional lymph node metastasis was observed in one case, and distant metastasis developed in two cases. All of the patients were treated with adjuvant postoperative irradiation. One patient died of disease at 11 months after the initial diagnosis, another was alive with disease at 8 months, and the third patient was alive without disease at 2 years and 3 months. Salivary duct carcinoma should be differentiated from low-grade salivary gland carcinomas using morphologic and clinical criteria because of its poor prognosis even with aggressive therapy.

Determination of selenium in the human brain by graphite furnace atomic absorption spectrometry

For the investigation of neurological disorders, a development of simple and accessible methods for determining selenium in human brain samples is required. We devised a method of determining selenium using graphite furnace atomic absorption spectrometry (GFAAS). An electrodeless discharge lamp provided the sufficient sensitivity to determine brain selenium. The matrix interferences were avoided by using high temperature, a prolonged pyrolysis step, and a palladium matrix modifier. The technique of standard addition was used to evaluate the sample concentrations. The accuracy of the method was confirmed by a bovine liver reference material. The detection limit of selenium was 0.04 ng. The determined selenium concentrations of human brain cortex and white matter were higher than those of putamen (115-155 and 206-222 ng/g wet wt, respectively). These GFAAS values agreed with those obtained by fluorometric analysis (r = 0.91, n = 10). Moreover, the GFAAS values were compatible to those reported by other researchers (99-274 ng/g wet wt), in which selenium concentrations in putamen also tended to be higher than the other two regions. We conclude that GFAAS is useful for selenium analysis in brain samples.

Lessons for neurotoxicology from selected model compounds: SGOMSEC joint report

The ability to identify potential neurotoxicants depends upon the characteristics of our test instruments. The neurotoxic properties of lead, methylmercury, polychlorinated biphenyls, and organic solvents would all have been detected at some dose level by tests in current use, provided that the doses were high enough and administered at an appropriate time such as during gestation. The adequacy of animal studies, particularly rodent studies, to predict intake levels at which human health can be protected is disappointing, however. It is unlikely that the use of advanced behavioral methodology would alleviate the apparent lack of sensitivity of the rodent model for many agents.

Evolution of our understanding of methylmercury as a health threat

Methylmercury (MeHg) is recognized as one of the most hazardous environmental pollutants, primarily due to endemic disasters that have occurred repeatedly. A review of the earlier literature on the Minamata outbreak shows how large-scale poisoning occurred and why it could not be prevented. With the repeated occurrences of MeHg poisoning, it gradually became clear that the fetus is much more susceptible to the toxicity of this compound than the adult. Thus, recent epidemiologic studies in several fish-eating populations have focused on the effects of in utero exposure to MeHg. Also, there have been many studies on neurobehavioral effects of in utero exposure to methylmercury in rodents and nonhuman primates. The results of these studies revealed that the effects encompass a wide range of behavioral categories without clear identification of the functional categories distinctively susceptible to MeHg. The overall neurotoxicity of MeHg in humans, nonhuman primates, and rodents appears to have similarities. However, several gaps exist between the human and animal studies. By using the large body of neurotoxicologic data obtained in human populations and filling in such gaps, we can use MeHg as a model agent for developing a specific battery of tests of animal behavior to predict human risks resulting from in utero exposure to other chemicals with unknown neurotoxicity. Approaches developing such a battery are also discussed.

Pure autonomic failure with motor neuron disease: report of a clinical study and postmortem examination of a patient

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Analysis of trace elements in the central nerve tissues with inductively coupled plasma-mass spectrometry

To investigate the roles of various elements in neurological disorders, multi-element analysis of limited quantities of samples in the central nervous system is required. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis suits this requirement, but spectral and non-spectral interferences are inevitable. We studied correction methods for the non-spectral interferences by analyzing signals of 21 elements in various concentrations of HNO3 as well as 5 major elements (Na, K, P, Ca, and Cl). Using internal standards, the interferences caused by the major elements were corrected, but the interferences caused by HNO3 were impossible to correct for the elements with high ionization potentials. Thus, we decided to use a standard addition method to correct these interferences. The spectral interferences on Mn and Fe rising from HNO3 or major elements were compared with the signals of samples. Although the interferences on Mn were negligible, those on Fe were considerable and careful blank subtraction were needed. We measured concentrations of elements in the spinal cord of 4 controls and a patient with amyotrophic lateral sclerosis (ALS) using the standard addition method. The concentrations of Mn, Se, Fe, and Zn in the controls were nearly the same as previously reported values, whereas Mn concentrations in the ALS patient were higher.

Distribution of selenium in human plasma detected by high performance liquid chromatography-plasma ion source mass spectrometry

The distribution of selenium in human plasma has been investigated by high performance liquid chromatography (HPLC) connected directly to inductively coupled plasma mass spectrometry (ICP-MS). Human plasma was loaded on to a size exclusion column and eluted with 0.01 M sodium phosphate buffer (pH 7.0) at a flow rate of 0.6 ml/min. Four peaks of selenium were detected in the chromatogram. The first selenium peak was obtained in the void volume. The retention time of the third peak was in accord with that of bovine serum albumin as a standard. The forth peak was thought to be a ghost. The method was applied to identify the chemical form of selenium in blood plasma immediately after intestinal absorption. The chromatographic pattern of selenium in postprandial human plasma was compared with that in fasting plasma. The first and third peaks in the postprandial plasma sample were slightly higher than those in the fasting plasma sample. This finding suggests that absorbed selenium is associated with the high molecular weight fraction and mercaptalbumin in blood plasma.

Polypyrimidine tract-binding protein and heterogeneous nuclear ribonucleoprotein A1 bind to human T-cell leukemia virus type 2 RNA regulatory elements

Efficient expression of human T-cell leukemia virus (HTLV) and human immunodeficiency virus structural proteins requires Rx and Rev proteins, respectively. Decreased expression of Gag and Env appears to be due, in part, to intragenic RNA sequences, termed cis-acting repressive sequences (CRS), and may be mediated by binding of specific cellular factors. We demonstrated previously that two cellular proteins, p60CRS and p40CRS, interact with HTLV type 2.5' long terminal repeat CRS RNA and that the interaction of both proteins with CRS RNA correlates with function (A. C. Black, C. T. Ruland, J. Luo, A. Bakker, J. K. Fraser, and J. D. Rosenblatt, Virology 200:29-41, 1994). By radioimmunoprecipitation of HeLa nuclear proteins UV cross-linked to CRS RNAs with murine monoclonal antibodies, we now show that p40CRS is heterogeneous nuclear ribonucleoprotein (hnRNP) A1 and p60CRS is polypyrimidine tract-binding protein or hnRNP I. These immunoprecipitation results were confirmed by an immunobinding assay with hnRNP I and hnRNP AI antibodies and by cross-competition electrophoretic mobility shift experiments. In addition, we mapped a putative hnRNP A1 binding site in U5 RNA and demonstrated that p40CRS (hnRNP A1) binding to that site correlates with CRS function. Since both hnRNP I and hnRNP A1 have been shown to influence splicing and potentially other steps in RNA processing, the binding of both hnRNP I and hnRNP A1 to HTLV RNA regulatory elements may alter retrovirus RNA processing and may be involved in regulation by Rex.

Inhibition of gamma-glutamyltranspeptidase decreases renal deposition of mercury after mercury vapor exposure

The alteration of renal deposition of mercury (Hg) after mercury vapor (Hg0) exposure was studied in mice pretreated with acivicin, a potent and irreversible inhibitor of gamma-glutamyltranspeptidase (GGT). Pretreatment with acivicin decreased renal Hg concentration by about 60% and significantly increased Hg concentration in the urine compared with the non-treated group. The results suggest that renal deposition of Hg after Hg0 exposure depends on renal GGT, which plays an important role in the uptake of GSH or GSH conjugates filtered through the glomeruli. It seems that the mechanism of renal Hg deposition after Hg0 exposure is similar to that after exposure to ionic Hg: a GGT-mediated incorporation of an Hg-GSH complex into renal tubular cells. The acivicin pretreatment after Hg0 exposure did not affect Hg concentrations in the liver and erythrocytes.

Consistent relationship between selenium and apolipoprotein A-II concentrations in the sera of fasting middle-aged male abstainers and regular consumers of alcohol

Several studies have suggested that selenium serum levels may be associated with serum lipids and apolipoproteins. In the present study, 99 clerical workers aged 40-49 yr were selected based on their drinking and smoking habits. The serum concentration of selenium was not affected by these lifestyle factors. The regular drinkers had raised serum high-density lipoprotein cholesterol, apo A-I, and apo A-II concentrations. Correlation analysis showed that serum selenium was positively and consistently associated with apo A-II regardless of alcohol consumption. Factor analysis revealed that serum selenium had no association with factors that represented each lipoprotein fraction (LDL, HDL, and VLDL). The present study indicates that serum selenium is positively correlated only with apo A-II levels.

The relationship between gastric secretion and type of early gastric carcinoma

To determine the relationship between gastric secretion and gastric carcinoma, we investigated gastric acid secretion and the fasting serum levels of pepsinogen I and gastrin in 50 Japanese patients with early gastric carcinoma. After the histological and macroscopic type of carcinoma had been determined, results were compared with findings in 50 Japanese control subjects whose gastric mucosa was endoscopically normal. The maximum gastric acid secretion and fasting levels of serum pepsinogen I were significantly lower in intestinal type gastric carcinoma than in diffuse type carcinoma and in the controls. They were also significantly lower in the non-ulcerative (elevated or flat) type than in the ulcerative (depressed) type of carcinoma. The serum gastrin levels in patients with early gastric carcinoma of either the intestinal or diffuse type were higher than those in the control subjects, though the difference was not significant. Gastric acid secretion and serum pepsinogen I levels were related with both the histological and macroscopic types of gastric carcinoma. These findings suggest that the serum pepsinogen I level might be useful as a maker for early gastric carcinoma of the intestinal type.

Effects of prolonged selenium deficiency on open field behavior and Morris water maze performance in mice

Neurobehavioral effects of prolonged Se deficiency were evaluated using ICR mice. Dams were fed Se-deficient or Se-adequate diet starting at 4 weeks before conception through the suckling period. After weaning, offspring of both groups were given the same diet as their dams were given. The behavior of these offspring was evaluated with open field apparatus (OPF) and Morris water maze. In OPF, Se-deficient females exhibited less locomotor activity, more defecation, and less entry to the center square areas than did the control females. No such difference was found in males. In the Morris maze, Se-deficient females showed slight but significant impairment during the initial phase of the trials. The behavioral changes in OPF and the maze might have been due to an altered reactivity to a novel environment, although this possibility needs further confirmation. The obtained data showed that the altered behavior was unlikely to be due to the changes in thyroid hormones. Mechanism of these behavioral effects is discussed in relation to possible neurochemical changes induced by Se deficiency.

[Effects of 5-fluorouracil in shrinking residual gastric cancer: a case report]

The patient was a 79-year-old man who underwent extensive gastrectomy and Billroth-II reconstruction for gastric ulcer in 1974. He complained of heartburn in November, 1992, and endoscopy for the residual stomach revealed IIb + IIa-like lesion mainly in the posterior wall of the anastomosed site, which was diagnosed as well differentiated adenocarcinoma. As the patient refused to be operated, 150 mg/day of 5-FU was administered. For 4 months before he decided to undergo operation, 12.9 g of 5-FU was administered in total. After rehospitalization, endoscopy of the residual stomach showed shrinkage of the lesion, and biopsy revealed no malignant findings. The pathological examination after total resection of the residual stomach showed atypism, but no evidence to support malignancy. He has continued to be well without sign of recurrence for 1 year since the operation. The administration of 5-FU is widely used as preoperative adjuvant chemotherapy. This case it is rare for 5-FU to cause the disappearance or falling off of malignant cells.

Selenium levels and glutathione peroxidase activities in blood in an andean high-altitude population

Selenium (Se) levels in blood (whole blood, erythrocytes and serum) and blood glutathione peroxidase (GSH-Px) activity were investigated in people living at high altitude in Bolivia (4,000 m above sea level). These parameters were compared to those of people living at low altitude (300 m above sea level). The Se levels in whole blood of the high-altitude subjects did not differ significantly from those of the low-altitude subjects. However, the Se levels in erythrocytes were significantly lower in the high-altitude subjects than in the low-altitude subjects, whereas serum Se levels were higher in the high-altitude subjects than in the low-altitude subjects. GSH-Px activity (Unit/g Hb) was significantly lower in the high-altitude subjects than in the low-altitude subjects. The mean corpuscular Hb concentration (MCHC), an indicator of the age of erythrocytes, in the high-altitude subjects was significantly higher than in the low-altitude subjects. These results show that the GSH-Px activity in the blood of the high-altitude subjects is relatively low. This may be due to their aged erythrocytes and/or to relatively low Se intake in the high-altitude population compared with low-altitude population.

An autopsy case of incomplete left atrial rupture following left atrial infarction associated with left ventricular myocardial infarction

We report a 78-year-old woman with incomplete left atrial rupture following left atrial infarction associated with left ventricular myocardial infarction. An autopsy revealed a hemopericardium. A large hematoma was observed in the posterior wall of the left atrium and a few small tears were found on the same wall. Near its origin, the left circumflex artery was severely sclerotic and completely occluded by fresh thrombus. Histologic examination revealed that large intramural hematoma longitudinally dissected the inner third of the posterior wall of the left atrium, and transversely dissected through the necrotic tissue to the pericardial sac to result in rupture. Coagulation necrosis and intramyocardial hemorrhage were also observed throughout the entire left atrium and the postseptolateral wall of the left ventricle.

Effects of buthionine sulfoximine (BSO) on mercury distribution after Hg(o) exposure

Effects of buthionine sulfoximine (BSO), a glutathione (GSH) depletor, on mercury (Hg) distribution were studied after mercury vapor (Hg(o)) exposure (3.2 mg/m3) in mice. BSO (1.6 g/kg, i.p.) significantly decreased the GSH levels in the liver, kidney and lung. Pretreatment with BSO increased Hg concentrations in the lung, liver and plasma, but decreased Hg concentration in the kidney. These findings indicate that GSH functions as a determinant in the changes of Hg distribution after Hg(o) exposure. Possible causes of the alterations in Hg distribution are discussed, including the anticipated enhancement in the Hg(o) oxidation process in the tissues with decreased GSH levels as well as the transportation of Hg2+ derived from oxidation of Hg(o). Concentrations of thiobarbituric acid reactive substances (TBARS) were determined as an indicator of oxidative damage, but the increase in TBARS was not detected in any tissue examined.

Stimulation of osteoinduction in bone wound healing by high-molecular hyaluronic acid

To study the osteoinductive action of hyaluronic acid (HA), we examined the effects of applying an elastoviscous high-molecular HA preparation on bone wound healing after bone marrow ablation. The middiaphyses of cortical bones from rat femurs were perforated with a round bar, and excavated marrow cavities were filled immediately with high-molecular HA. Bone marrow ablation without HA was used to prepare controls. On post-ablation days 1, 2, 4, 7, and 14, animals were perfusion-fixed with an aldehyde mixture, and dissected femurs were examined by means of light, transmission-, and scanning-electron microscopy. In controls, the wounded marrow cavities were first filled with blood and fibrin clots (days 1 and 2), then with granulated tissues containing macrophages, neutrophils, and fibroblastic cells (day 4). New bone formation by differentiated osteoblasts was observed at 1 week post-ablation; at 2 weeks, the perforated cortical bones and marrow cavities were filled mostly with newly formed trabecular bone. In bones to which HA had been applied, new bone formation already had been induced by day 4 on both the peri- and endosteal surfaces of the existing cortical bones. At 1 week post-ablation, marrow cavities were completely filled with newly formed trabecular bones, in which active bone remodeling by osteoblasts and osteoclasts had occurred. Granulated tissues were replaced rapidly by normal marrow cells. These results suggest that high-molecular HA is capable of accelerating new bone formation through mesenchymal cell differentiation in bone wounds.

Brain selenium status and behavioral development in selenium-deficient preweanling mice

The influence of Se deficiency on behavioral development in preweanling mice was evaluated. Female ICR mice were fed either Se-deficient or control diet (containing < 20 or 400 ng Se/g diet, respectively) from 4 weeks before conception to the end of the suckling period. In the offspring of Se-deficient dams, liver and brain Se levels were reduced to < 5% and 60% of those in the control offspring, respectively, from as early as the third postnatal day. At weaning, brain Se content exceeded the hepatic one in Se-deficient offspring, whereas in the control offspring the liver contained 10 times more Se than the brain did. Thus, tissue-specific metabolism of Se was already functioning during the neonatal period. When placed in a thermogradient and allowed to move along the gradient, Se-deficient offspring exhibited a preference for a significantly warmer environment than did the controls. They also showed slightly retarded development of walking ability. These results showed that Se-deficient offspring differed from the controls in behavioral development. Possible mechanisms of these alterations are discussed.

Geographical variation in urinary mercury concentrations among populations living in highland and lowland Bolivia

Mercury (Hg) concentrations were determined in spot urine samples of populations living in the highland and lowland areas of Bolivia. The mean levels of the Hg (U-Hg) were 0.43 and 0.34 micrograms Hg/g creatinine in lowlanders and in highlanders, respectively, which did not suggest existence of high-level exposure to Hg in these populations. In both highlanders and lowlanders, there was a marked difference in levels of U-Hg among different populations. Several lines of evidence suggested that local dietary patterns resulted in the observed difference in U-Hg among different populations. Several lines of evidence suggested that local dietary patterns resulted in the observed difference in U-Hg levels, although the responsible food items could not be specified. In most of the populations examined, females showed higher U-Hg levels than males. Other factors possibly related to the observed geographical differences are discussed.

Milk transfer and tissue uptake of mercury in suckling offspring after exposure of lactating maternal guinea pigs to inorganic or methylmercury

Maternal guinea pigs were injected with mercuric chloride (HgCl2; 1 mg Hg/kg body weight) or methylmercury (MeHg; 1 mg Hg/kg) 12 h after parturition, and exposure of the offspring to mercury (Hg) via breast milk were studied on days 3, 5 and 10 postpartum. Milk Hg concentrations were lower than maternal plasma Hg concentrations regardless of the form of Hg given to the dams. Milk Hg was higher in HgCl2-treated dams than in MeHg-treated dams. In MeHg-treated dams, MeHg was separately determined. While the ratio of MeHg to T-Hg decreased in the dams' plasma, it did not in the milk. There was a strong correlation between milk and plasma T-Hg concentrations in HgCl2 treated dams. In the milk of MeHg-treated dams, the plasma MeHg concentrations correlated better than did the plasma T-Hg concentrations. In the offspring, regardless of the chemical forms of Hg given to the dams, the highest Hg concentrations were found in the kidney, followed by the liver and the brain. Brain Hg concentrations were, however, significantly higher in the offspring of MeHg-treated dams than in those of HgCl2-treated dams. In addition, Hg levels in the major organs of the offspring of HgCl2-treated dams peaked on day 5 postpartum, while those of MeHg-treated dams did not show a significant decrease up to day 10 postpartum. These facts indicate that the two chemical forms of Hg were transferred to the offspring via the breast milk and were distributed differently, depending on the chemical form, to the offspring's tissues.

[A clinical study of pepsinogen I and II producing gastric carcinomas]

Anti-human pepsinogen (PG) I and II monoclonal antibodies were used in an immunohistochemical study of 56 cases of gastric carcinoma (37 early stage and 19 advanced stage). We examined the relationship between positivity of the carcinoma for producing PG I and II and serum PG I and II levels. We found that in 2 cases (3.6%), the carcinoma produced PG I and in 11 cases (19.6%), it produced PG II. Early gastric carcinomas and differentiated-type carcinomas produced PG II more frequently than advanced and undifferentiated-type carcinomas. Also, type II c carcinomas and carcinomas located in the C area of the stomach produced PG II more frequently. But there was no significant difference between PG I and II-positive and negative cases in relation to both serum PG I and II levels. Moreover, the rate of positivity did not correlate with cases of abnormally high levels of serum PG I and II, (except in 1 case with abnormally high serum PG I in which PG II was produced.) These results suggest that there is no significant relationship between PG I or II-producing gastric carcinomas and serum PG levels. Furthermore, we examined PG II-producing and non-producing carcinomas in relation to the grade of inflammation, atrophy and intestinal metaplasia in gastric mucosa. However, there was no statistically significant difference among these factors. Only serum PG I and II levels were related to these parameters.

[Long-term follow-up study after permanent pacemaker implantation in patients aged 60 years or over with sick sinus syndrome]

Ninety-five patients aged 60 years or over with a permanent pacemaker implanted for sick sinus syndrome were divided into two groups: 32 patients with physiological pacing (group P) and 63 patients with ventricular pacing (group V). The mean follow-up period was 45.0 +/- 36.6 months in group P and 50.3 +/- 37.8 months in group V. Paroxysmal atrial fibrillation (Af) occurred in 28% of group P and 71% of group V (p < 0.05). The incidence of stable Af was also lower in group P than in group V (9% vs. 30%, p < 0.05). None of group P with only bradyarrhythmia had stable Af. However, 6 of 21 patients (29%) in group V with bradyarrhythmia showed stable Af. There was no significant difference in stable Af between group P with bradycardia-tachycardia syndrome (BTS) and group V with BTS (19% vs. 31%). A lower incidence of embolic events was also observed in group P (3% vs. 25%, p < 0.05). Nine of 16 patients with embolic events in group V died of complications following embolism (8 patients; cerebral embolism, one patients: renal and superior mesenteric arterial embolism). The survival rates at 5 and 10 years were 80% and 69%, respectively, for group P and 56% and 33% for group V (p < 0.01). Thus, with regard to permanent pacing for patients with sick sinus syndrome, physiological pacing should be selected for control of morbidity and total mortality.

Mercury and selenium contents in amyotrophic lateral sclerosis in Hokkaido, the northernmost island of Japan

We evaluated the pathogenicity of mercury (Hg) and selenium (Se) which are supposed to be one of the risk factors in the development of amyotrophic lateral sclerosis (ALS). Hg and Se contents were measured in plasma, blood cells, scalp hair samples of 21 sporadic ALS patients and 36 controls, who included 19 patients with other neurological diseases, in Hokkaido, the northernmost island of Japan. Hg and Se levels in plasma and blood cells of ALS patients were significantly lower in advanced staged ALS patients than controls. Low Hg and Se contents in ALS, being correlated with their disabilities and nutritional conditions, would rather reflect the disease contracted states than the pathogenic roles in ALS.

Gastric acid secretion, serum pepsinogen I, and serum gastrin in Japanese with gastric hyperplastic polyps or polypoid-type early gastric carcinoma

We determined the maximum secretion of gastric acid and the fasting serum levels of pepsinogen I and gastrin in Japanese patients with gastric hyperplastic polyps or polypoid-type early gastric carcinoma, comparing those findings with observations in control subjects. Both the maximum acid secretion and fasting levels of serum pepsinogen I were significantly lower in the patients with gastric hyperplastic polyps or polypoid-type early gastric carcinoma than in the controls. Fasting serum gastrin levels were significantly higher in the patients with gastric hyperplastic polyps than in the other two groups of subjects. These data demonstrated that the combination of hypochlorhydria, a low level of pepsinogen I, and hypergastrinemia (type-A gastritis) was common in the patients with gastric hyperplastic polyps, whereas hypochlorhydria and a low pepsinogen I without hypergastrinemia (type-B gastritis) were common in those with polypoid-type early gastric carcinoma.

Extracellular Ca(2+)-dependent potentiation by cocaine of serotonin- and norepinephrine-induced contractions in rat vascular smooth muscle

Using front-surface fluorometry, we determined the effects of cocaine on force and cytosolic Ca2+ concentration ([Ca2+]i) in the rat aorta. We also examined the effects of cocaine on 45Ca2+ influx. Cocaine (10(-7) to 10(-4) M) alone did not alter the resting level of [Ca2+]i and force. Cocaine (< 10(-4) M), in a concentration-dependent manner, potentiated the 10(-6) M serotonin (5-HT)-induced or 10(-8) M norepinephrine (NE)-induced sustained increase in [Ca2+]i and force in the presence of extracellular Ca2+, whereas it had no potentiating effects in Ca(2+)-free solution. Similar potentiating effects of cocaine were observed in pharmacologically denervated strips. Cocaine (10(-5) M) produced a leftward shift of concentration-response curves for both 5-HT- and NE-induced increases in [Ca2+]i and force with no effect on the maximal response or the relations between [Ca2+]i and force. Cocaine (10(-5) M also accelerated the 45Ca2+ influx during activation by 10(-6) M 5-HT or by 10(-8) M NE. Cocaine (> 10(-3) M) inhibited 5-HT-, NE-, and high-K+ depolarization-induced contractions accompanied by decreases in [Ca2+]i in normal physiological salt solution and 5-HT- or NE-induced transient increase in [Ca2+]i and force in Ca(2+)-free physiological salt solution. Thus, low concentrations of cocaine potentiate NE- or 5-HT-induced contraction by augmenting the increase in [Ca2+]i. These potentiating effects may derive from either an increase in the affinity of the receptors to agonists or an increase in the Ca2+ influx. On the other hand, high concentrations of cocaine (> 10(-3) M) have a relaxant effect on vascular smooth muscle, as a result of a decrease in [Ca2+]i.

Identifying proteins from two-dimensional gels by molecular mass searching of peptide fragments in protein sequence databases

A rapid method for the identification of known proteins separated by two-dimensional gel electrophoresis is described in which molecular masses of peptide fragments are used to search a protein sequence database. The peptides are generated by in situ reduction, alkylation, and tryptic digestion of proteins electroblotted from two-dimensional gels. Masses are determined at the subpicomole level by matrix-assisted laser desorption/ionization mass spectrometry of the unfractionated digest. A computer program has been developed that searches the protein sequence database for multiple peptides of individual proteins that match the measured masses. To ensure that the most recent database updates are included, a theoretical digest of the entire database is generated each time the program is executed. This method facilitates simultaneous processing of a large number of two-dimensional gel spots. The method was applied to a two-dimensional gel of a crude Escherichia coli extract that was electroblotted onto poly(vinylidene difluoride) membrane. Ten randomly chosen spots were analyzed. With as few as three peptide masses, each protein was uniquely identified from over 91,000 protein sequences. All identifications were verified by concurrent N-terminal sequencing of identical spots from a second blot. One of the spots contained an N-terminally blocked protein that required enzymatic cleavage, peptide separation, and Edman degradation for confirmation of its identity.

[An elderly case of supernormal conduction in the posterior division of the left bundle branch]

An electrophysiologic study was performed in a 95-year-old man with bifascicular block (right bundle branch block and left anterior hemiblock). During sinus rhythm (AA interval = 980 ms), every sinus beat was conducted to the ventricle. The AH interval was 130 ms and HV interval was 50 ms. A programmed premature atrial stimulation was performed after 8 paced beats at a slightly shorter cycle length than the sinus cycle length (900 ms). As the atrial coupling interval was shortened, the H1H2 interval also shortened. At an H1H2 interval of 680 ms the premature atrial beat was blocked distal to the recording site of the His potential. The block persisted up to an H1H2 interval of 560 ms. AV conduction resumed paradoxically when the H1H2 interval was further shortened to intervals lasting 540-490 ms. During this period the H2V2 interval was 50 ms. At still shorter H1H2 intervals, H2 was again blocked. The H2V2 intervals during this phase of improved conduction were unchanged compared with those of other conducted beats. Therefore normalization due to the gap phenomenon could be ruled out, and the improved conduction could be explained by a phenomenon of supernormal conduction in the posterior division of left bundle branch.

[Screening of obese or lean schoolchildren; difficulty in applying "the Japanese weight and height standards for estimating over- and under-weight" to younger people]

Obesity or leanness of an individual tends to continue from childhood to adult ages. It is therefore desirable to establish a single standard for obesity/leanness that is applicable throughout these stages of life. Trials were made in the present study to examine if 'the Japanese weight and height standards for estimating over- and under-weight' (established for adults by the Ministry of Health and Welfare of the Government of Japan) is applicable also to younger people. The standard is developed with two assumptions that both height and logarithm of weight distribute normally. The height and weight of about 83,000 6th-grade children in primary schools (12 years of age; with boys and girls of an equal number), and about 78,000 3rd-year-children in junior high schools (15 years of age) were available. The analyses of the data disclosed that, whereas height distributes normally, their weight does not fit with normal distribution when converted logarithmically or even when the conversion is made after subtraction of a constant value from the weight. The distribution pattern of weight of children was however essentially the same, independent of height. Thus, it was possible to classify the children into five categories of definitely obese (10%), tending toward obesity (15%), normal (50%), slim (15%) and thin (10%) groups with the same statistical parameters, regardless of their height excluding extremely tall or short cases.

Role of extracellular and intracellular sources of Ca2+ in sarafotoxin S6b-induced contraction of strips of the rat aorta

1. The effect of sarafotoxin S6b (sarafotoxin), a vasoconstrictor peptide, on cytosolic Ca2+ concentration ([Ca2+]i) and force in rat aortic strips loaded with fura-2 was determined by front-surface fluorometry. The objective was to elucidate the role of extracellular and intracellular Ca2+ in the mechanism of action of this peptide. 2. In the presence of extracellular 1.25 mM Ca2+, sarafotoxin induced a biphasic response consisting of an initial rapid increase in [Ca2+]i followed by a secondary sustained increase. Tension developed slowly but was sustained during the application of sarafotoxin. Diltiazem (10 nM-0.1 mM) partially inhibited both the increases in [Ca2+]i and tension. 3. In the presence of extracellular Ca2+, the force developed in relation to the increase in [Ca2+]i ([Ca2+]i-force relationship) observed with sarafotoxin was much greater than that observed upon K+ depolarization. In the presence of diltiazem the sarafotoxin-induced [Ca2+]i-force relationship was shifted even further to the left. 4. In the absence of extracellular Ca2+, sarafotoxin induced a transient increase in [Ca2+]i and a sustained contraction. Extending the incubation time in Ca(2+)-free physiological solution, resulted in smaller responses. However, after 60 min in Ca(2+)-free solution, sarafotoxin induced a sustained contraction but no change in [Ca2+]i. This residual contraction was inhibited by H-7, which is known to inhibit protein kinase C. 5. After treatment with caffeine to reduce intracellular stored Ca2+, sarafotoxin could still elicit increases in [Ca2+]i and in tension, showing that the caffeine-sensitive intracellular Ca2+ store partially overlaps with the sarafotoxin-sensitive store. 6. We conclude that, in addition to those components of contraction dependent on extracellular- and on intracellularly stored Ca2 , sarafotoxin can also induce contraction without increasing [Ca2+],. This component may be partially linked to the activation of protein kinase C and may contribute, in part, to the leftward shift of the [Ca2+]i-force relationship in the presence of sarafotoxin.