Methylmercury toxicity in dissociated rat brain neurons: modification by l-cysteine and trimethylbenzylmercaptan and comparison with dimethylmercury and N-ethylmaleimide

The effects of methylmercury (MeHg) on dissociated rat cerebellar neurons were compared with those of MeHg conjugated with l-cysteine (MeHg-Cys conjugate), dimethylmercury (DiMeHg), N-ethylmaleimide (NEM) and ionomycin using a flow cytometer and two fluorescent dyes, fluo-3-AM and ethidium bromide. The efficacies of MeHg to increase intracellular concentration of Ca(2+) ([Ca(2+)]i) and to decrease cell viability were greatly reduced by conjugating MeHg with l-cysteine. It was not due to a decreased lipophilic property of MeHg-Cys because the conjugation of MeHg with trimethylbenzylmercaptane, a lipophilic substance, also reduced the efficacies. It seems that the reactivity of MeHg to SH-groups is responsible for the MeHg-induced toxicity since NEM increased [Ca(2+)]i and decreased cell viability while DiMeHg did not significantly affect them. However, the toxicity of MeHg was not explained only by the reactivity of MeHg to SH-groups since NEM-induced changes in fluo-3 and ethidium fluorescence were different from MeHg-induced ones. Ionomycin-induced changes in those fluorescence were also different although ionomycin decreased cell viability after increasing [Ca(2+)]i. Therefore, it is suggested that the mechanism of MeHg toxicity is more complicated than those of NEM and ionomycin.

Masticatory function and its effects on general health

One of the main goals of dentistry is to preserve a lifelong healthy masticatory function. Recent studies have shown that mastication is of great importance, not only for the intake of food but also for the systemic, mental and physical functions of the body. The purpose of this review is to compile the latest scientific information concerning the relationship between mastication and general health.

[Rheumatoid nodule diagnosed by thoracoscopy using flexible fiberoptic bronchoscope]

A 51-year-old man had been treated at a nearby hospital since 1993 for rheumatoid arthritis. Right pectoralgia developed in December 1994, and the patient consulted a nearby hospital, which detected right pleural effusion retention was pointed out on chest x-ray films. The patient was referred and admitted to our hospital. Rheumatic pleurisy was suspected because of a high serum rheumatoid factor(RF)level and high RF and high rheumatoid arthritis hemagglutination levels in the pleural effusion. However, due to a high adenosine deaminase level in the pleural effusion tuberculous pleurisy could not be ruled out. After drainage through a trocar catheter, the thoracic cavity was examined by thoracoscopy through the site of catheter insertion. As a result, sporadic bluish white nodular lesions were observed on the pleura. Granuloma formations presenting a palisade arrangement of giant cells were also observed, and pathologically diagnosed as rheumatoid nodules, thus providing the basis for a diagnosis of rheumatic pleurisy. Treatment with an increased dose of prednisolone achieved a rapid remission of the pleural effusion. Our experience underscored the usefulness of thoracoscopy as a means diagnosing of rheumatic pleurisy.

Protective actions of 5'-n-alkylated curcumins on living cells suffering from oxidative stress

To elucidate the roles of 5'-n-alkyl chains of curcumin derivatives in their protective actions on cells against oxidative stress, we compared the efficacy of curcumin and 5'-alkylated curcumins to inhibit the peroxidation of linoleic acid and to protect rat thymocytes suffering from H2O2-induced oxidative stress with their permeation into cells. The inhibitory action of 5'-n-alkylated curcumins on lipid peroxidation increased as the length of hydrocarbon chains of 5'-n-alkylated curcumins was prolonged. This potency order was not confirmed for the protective actions of 5'-n-alkylated curcumins on cells against oxidative stress. Among 5'-alkylated curcumins, the most potent protective action was observed for 5'-n-C3H7-curcumin because it had the greatest permeation into the cells. Further increases in the length of hydrocarbon chains (up to n-C19H39) of 5'-n-alkylated curcumins greatly attenuated their protective actions by reducing their permeation into the cells.

Characterization and optimization of the flow pattern inside a diaphragm blood pump based on flow visualization techniques

We applied two different flow visualization techniques to obtain detailed information on the inside flow of the diaphragm blood pump of our electrohydraulic total artificial heart system to determine the optimum washout effect that would result in better antithrombogenicity. Major orifice directions of the inflow and outflow Bjork-Shiley valves of the left blood pump were independently changed to create 17 varied patterns. The character and velocity of the main flow at the diaphragm-housing junction were acquired using a laser light sheet method with polyethylene tracers. Wall shear flow, a major factor governing washout in the blood pump, was estimated by a newly developed paint erosion method. In this method, quantitative evaluation for an index of washout effect was made by calculating the residual ratio of the paint on the blood pump inner surface at 30 sec of pumping. When a single circular flow was consistently observed by the laser light sheet method, the paint residual ratio become low, indicating washout was relatively good. At the lowest paint residual ratio, the center of the circular flow observed by the laser light sheet method was located at the geometric center of the blood chamber. In conclusion, the flow pattern inside the blood pump could be characterized by combined use of these two flow visualization techniques, and the significant role of circular flow in better washout was clarified.

The H1Sigma+<INF POS="STACK">g (v = 0 and 1) and EF1Sigma+<INF POS="STACK">g (v = 28 and 32) States of D2: Term Values and Fluorescence Lifetimes

The extreme ultraviolet-visible double resonant excitation method was applied to the gerade Rydberg states of D2 molecules. Tunable coherent extreme ultraviolet radiation near 103 nm prepared D2 in the B1Sigma+<INF POS="STACK">u (v = 7, J) state. Visible laser light subsequently brought them to the H1Sigma+<INF POS="STACK">g (v = 0 and 1), EF1Sigma+<INF POS="STACK">g (v = 28 and 32), and GK1Sigma+<INF POS="STACK">g (v = 2 and 5) states. Our term values for the GK1Sigma+<INF POS="STACK">g state were in complete agreement with previous values, while deviations beyond the experimental error were found for the H1Sigma+<INF POS="STACK">g (v = 1) and EF1Sigma+<INF POS="STACK">g (v = 28 and 32) states. The fluorescence lifetimes, measured under a collision-free environment for the first time, were in reasonable agreement with ab initio calculations. Copyright 1998 Academic Press.

Detection of disease-specific augmentation of abnormal immunoglobulin G in sera of patients with rheumatoid arthritis

Galactose-free immunoglobulin G (IgG), which is known to be higher in the sera of patients with rheumatoid arthritis, was prepared from IgG of healthy volunteers using enzymes. Its reactivity to lectins was analyzed. The galactose-free IgG showed no reactivity to Ricinus communis agglutinin 120 but displayed greater reactivity to concanavalin A and Lens culinaris lectin than did intact human IgG. Then, IgG in serum samples was bound to protein A immobilized on a nitrocellulose membrane, and its reactivity to biotinylated concanavalin A was measured with streptavidin-conjugated horseradish peroxidase. When the reactivity to concanavalin A of IgG in sera from healthy individuals and patients with rheumatoid arthritis (RA), osteoarthritis, systemic lupus erythematosus, or hepatic disease was compared, higher levels were shown in patients with RA, notably in 60% of the seronegative patients and 80% of the early phase patients. Therefore, it was suggested that augmentation of the abnormal IgG in sera was highly specific to patients with RA and that this novel serum test could be very useful for an accurate diagnosis of this disease.

CMDME (curved mesh diagram of mandibular excursion) method for visualization and diagnosis of mandibular movement

The CMDME (curved mesh diagram of mandibular excursion) method was developed for easy visualization and diagnosis of mandibular movement. This method uses measured mandibular movement to produce a diagram of the range, shape, and inclination of mandibular excursion in three dimensions using any arbitrary landmark of the mandible. First, the mandibular movement of a subject was measured by an opto-electronic movement analysis system capable of measuring mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. For the measurement, the subject was initially instructed to perform four repetitions of mandibular excursion at will, with tooth contact, each lasting 30 s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an attempt was made to match these positions to intersection points (0.1 mm apart) of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal position at the origin. The CMDME method can visualize mandibular excursion, and can be used to compare several landmarks, different subjects, or different times. This makes this method an effective diagnostic tool for mandibular movement.

Tissue and cell type specificity of the human neurotrophin-3 promoter region in transgenic mice

To examine the tissue and cell type specificity of the human neurotrophin-3 (NT-3) promoter, we generated transgenic mice bearing the 3.3 kbp upstream region of the human NT-3 gene linked to the bacterial chloramphenicol acetyltransferase (CAT) gene as a reporter. Eight independent founders of transgenic mice were obtained, and four of them transmitted the transgene to their offsprings. Among three lines of four transgenic mice at 6 weeks of age, a high level of production of CAT protein was detected in the spleen and a low level in the brain. By in situ hybridization analysis, CAT gene expression was detected in the hippocampal neurons and in the cerebellar granular neurons of the transgenic mouse brain. These results suggest that the 3.3 kbp 5' flanking region of the human NT-3 gene has adequate promoter activity in vivo and that its expression pattern resembles the endogenous gene.

Structural changes in the oligosaccharide moiety of human IgG with aging

In order to elucidate the relationship between glycosylation of IgG and aging, oligosaccharide structures of human IgG purified from sera of men and women aged 18 to 73 years were investigated. Oligosaccharides were liberated quantitatively from IgG by hydrazinolysis followed by N-acetylation and were tagged with p-aminobenzoic acid ethyl ester. The oligosaccharide structures were then analyzed by HPLC in conjunction with sequential exoglycosidase digestion. All IgG samples were shown to contain a series of biantennary complex type oligosaccharides which consisted of +/-Galbeta1-4GlcNAcbeta1-2Manalpha1-6(+/-GlcNAcbeta 1-4)(+/-Galbeta1-4GlcNAcbeta1-2Man(alpha)1-3)Man(beta)1-+ ++4GlcNAcbeta1-4(+/- Fucalpha1-6)GlcNAc and their mono- and disialo glycoforms in different ratios. In female IgG samples only, the incidence of non-galactosylated oligosaccharides with non-reducing terminal GlcNAc residues increased with aging (r>0.8), whereas that of digalactosylated oligosaccharides decreased (r<-0.8). A weaker correlation was observed between aging and the incidence of neutral and monosialo oligosaccharides in female IgG (r=0.461 and r= -0.538, respectively) and between aging and the incidence of oligosaccharides with a bisecting GlcNAc in both male and female IgG samples (r=0.566 and r=0.440, respectively). In addition, a significant change with aging in the galactosylation of IgG oligosaccharides was observed in females in their thirties, fifties, and sixties (p<0.02, p<0.01, and p<0.04, respectively). These findings may contribute to our understanding of autoimmune diseases such as rheumatoid arthritis in which glycosylation is involved.

[Rapid tapering of cyclosporine for cytogenetic relapse shortly after bone marrow transplantation in a patient with chronic myeloid leukemia]

A 53-year-old female case of cytogenetically relapsed chronic myeloid leukemia after allogeneic bone marrow transplantation (BMT) who achieved remission by withdrawal of immunosuppressant is reported. On day 690 of this presentation she is well and alive with performance status of 100%. She had episodes of cyclic oscillation of her neutrophil count during hydroxyurea therapy lasting 1 year before transplantation. Increase of the neutrophils at the time of BMT might have contributed to her early relapse on day 207. Withdrawal of immunosuppressant was successful at least in this case.

Two cases of intrapulmonary lymph node presenting as a peripheral nodular shadow: diagnostic differentiation from lung cancer

We present two cases of intrapulmonary lymph node. The patients were a 44-year-old woman and a 71-year-old man each with a small peripheral nodule in the lung. On computed tomography (CT) scans, both nodules were spiculated. Since histological diagnosis could not be obtained by bronchoscopic examination or CT-guided needle biopsy, they underwent video-assisted thoracoscopic surgery. Histological examination of the resected material revealed that both nodules were composed of lymph node. Intrapulmonary lymph node has until recently been assigned no clinical significance; however, differential diagnosis of this lesion from lung cancers and other metastatic tumors is now clinically important.

Prolonged nonpulsatile left heart bypass with reduced systemic pulse pressure causes morphological changes in the aortic wall

We investigated the morphological changes in the aorta due to reduced systemic pulse pressure in prolonged nonpulsatile left heart bypass (LHB). Nineteen adult goats were divided into 3 groups, the nonpulsatile group in which nonpulsatile LHB was conducted, the pulsatile group in which pulsatile LHB was conducted, and the control group used as the normal control. The average aortic pulse pressures were 12, 47, and 37 mm Hg, respectively. The descending aorta was subjected to morphological examination. In the nonpulsatile group, the wall was significantly thinner, and the volume ratio of smooth muscle cells (SMCs) was much lower. In terms of the SMC type classification, the proportion of SMCs with low activity and low contractility was higher, and the cell density of the SMCs was increased compared to those in the other groups. These results indicate that prolonged nonpulsatile LHB causes morphological atrophic changes in the aorta.

Rapid identification of Leishmania species from formalin-fixed biopsy samples by polymorphism-specific polymerase chain reaction

The precise identification and classification of Leishmania species is important for public health surveillance since different species cause different clinical features of the disease. A highly specific polymerase chain reaction (PCR) panel was developed to enable the identification of the five major Leishmania species that cause New World cutaneous leishmaniases. The primers used for this panel were designed to distinguish the polymorphism in sequences of commonly amplified DNA bands of the parasites produced by arbitrarily primed PCR. These polymorphism-specific PCR diagnoses were performed with formalin-fixed biopsy specimens of the leishmanial lesions from four patients in Ecuador and one hamster skin lesion, and these lesions were determined to be caused by Leishmania (Viannia) panamensis, L. (Leishmania) mexicana, and L. (L.) amazonensis. The PCR panel may offer an important and practical approach to the standardized identification of Leishmania species in field examinations.

Cytotoxic actions of FTY720, a novel immunosuppressant, on thymocytes and brain neurons dissociated from the rat

Effects of FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol HCl), a novel immunosuppressant, were examined on neurons and thymocytes respectively dissociated from rat brains and thymus glands using a flow cytometer to see if FTY720 exerts cytotoxic actions not only on spleen cells as previously reported but also on the other cells. FTY720 at a concentration of 10 microM deteriorated almost all of the thymocytes, while it was not the case for brain neurons. FTY720 increased the intracellular concentration of Ca2+ ([Ca2+]i) of thymocytes in both the presence and absence of external Ca2+, although the [Ca2+]i increased by FTY720 in the presence of external Ca2+ was much greater than that in the absence of external Ca2+. Thus, FTY720 may increase the membrane permeability of Ca2+ and release Ca2+ from intracellular Ca2+ stores in thymocytes. Furthermore, the number of thymocytes stained with ethidium, a dye impermeant to intact membranes, time-dependently increased after drug application. Therefore, FTY720 at concentrations of 3 - 10 microM non-specifically increases the membrane permeability of thymocytes, resulting in necrotic cell death, although FTY720 at micromolar concentrations was reported to induce apoptosis of spleen cells.

A longitudinal observation of the postnatal craniofacial growth in artificial monozygotic twin mice

An artificial monozygotic twin mouse produced by bisecting a 16-cell stage embryo with a fine glass-needle and then transferring a pair of demi-embryos together into the right uterus of a pregnant recipient female mouse after a 24 hr in-vitro cultivation allowed us to examine the postnatal growth changes in monozygotic twin mice. With regard to the preimplantational growth process of the embryo, we investigated the success rate of bisecting an embryo into paired demi-embryos, the developmental ability of the bisected demi-embryo up to the early blastocyst, and the production rate of such monozygotic twin mice. The items examined in the postnatal growth process of the monozygotic twin mouse were the growth curve of the twin weight and the craniofacial size of the monozygotic twin mouse by cephalometric observations at the 3rd, 10th, 21st, 42nd, 70th, and 100th postnatal days, respectively. The following results were thus obtained. 1) The success rate of bisecting the 16-cell stage embryos into a paired demi-embryos was 86.1% (2,528/2,936). As a result, 2,301 of 2,528 paired demi-embryos could develop up to blastocysts after 24 hr of in-vitro cultivation (91.0%). 2) In addition 42 of the 394 (10.7%) recipient female mice, which had been transferred as paired demi-embryos and delivered a litter, resulted in 31 singleton mice (7.9%) or 11 paired monozygotic twin mice (2.8%), respectively. 3) The weight of each twin increased rapidly up to the 42nd day but thereafter only increased gradually up to the 100th day. The within-pair difference among each paired monozygotic twin mouse could be observed from after the 21st day until the 100th day. 4) Both the dorsoventral craniofacial size of each twin mouse and the lateral craniofacial size of each monozygotic twin mouse increased rapidly up to the 42nd day and thereafter gradually reached a plateau by the 100th day. Almost no within-pair difference was observed among each paired monozygotic twin mouse after weaning up to the 100th day. Based on these results, it is thus concluded that the craniofacial growth of each paired monozygotic twin mouse more closely resembled the growth pattern than that of the somatic growth, which thus indicated that the craniofacial growth was more greatly controlled by the genetic effect than the somatic growth. Furthermore, these findings thus suggest that an embryo bisection is an essential for producing artificial monozygotic twin mice from paired demi-embryos. Therefore, artificial monozygotic twin mice are considered to be a useful animal model for examining the effect of genetic-environment interaction on either the prenatal dento-craniofacial morphogenesis or the postnatal craniofacial growth in mice.

Characteristics of protrusive and lateral excursions of the mandible in children with the primary dentition

This study characterizes the mandibular protrusive and lateral excursions of children with primary dentition. With use of a Selspot system, the protrusive and lateral excursions of nine children with the primary dentition and nine adults with the permanent dentition were measured and compared. This system was able to analyse the simultaneous movements of multiple points on the mandible of a subject in three dimensions. Furthermore, the system proved appropriate for use in young children because of the small burden imposed on them during the measurements. Using this subject-friendly system, the directions of the mandibular excursion for five reference points on the mandibular dental arch at each measurement distance (i.e. at 0.5 mm intervals) for three projected angles (frontal, sagittal and horizontal) were calculated. From the results it was found that the excursions of the primary dentition can move more horizontally and more forward with small descent compared with the permanent dentition. The underlying reason for these findings may be physiological growth, maturation, and adaptation of the occlusal function.

Satiation and masticatory function modulated by brain histamine in rats

Both the ventromedial hypothalamus (VMH) and the mesencephalic trigeminal sensory nucleus (Me5) are densely innervated by histaminergic neurons. The depletion of neuronal histamine (HA) from the Me5 by the bilateral microinfusion of 448 nmol/rat alpha-fluoromethylhistidine (FMH), a specific suicide inhibitor of histidine decarboxylase, reduced the eating speed and prolonged meal duration, while leaving the meal size unaffected. HA depletion from the VMH increased the size of the meal and prolonged its duration, but not the eating speed. When the HA turnover rate was measured at 15 min after the scheduled feeding following fasting for less than 24 hr, the rate increased in the region including the Me5, but not in the hypothalamus. The turnover rate reached higher levels at 60 min in both regions. Gastric intubation of an isocaloric liquid diet or an equivolume of water with the liquid diet abolished the increase in HA turnover both in the Me5 region and the hypothalamus. The present findings indicate that brain HA thus modulates satiation through both the VMH and masticatory function as well as due to the action of the Me5. The HA function activated by mastication began earlier in the Me5 and later in the hypothalamus due to a signal originating from the oral proprioceptors and initiated by chewing.

DX9065a, an Xa inhibitor, inhibits prothrombin-induced A549 lung adenocarcinoma cell proliferation

In this study we demonstrate that prothrombin activates the cell proliferation of the lung adenocarcinoma A549 cells. The A549 cell expresses factor Xa-like prothrombinase activity on its surface and prothrombin was converted to thrombin on the cell surface. Furthermore, thrombin induced the activation of PKC, increased [Ca2+]i and potentiated MAP kinase activity through thrombin receptor. The mitogenic activity of prothrombin and the conversion to thrombin were completely abolished by the synthetic coagulation factor Xa inhibitor, DX9065a. These findings suggest that DX9065a is an effective agent for a therapeutic strategy against cancer itself and prothrombotic complications associated with malignancy.