[Outbreak of measles in a hospital and measures taken against hospital infection--evidence of cost and benefits]

In Japan, an isolated vaccine of measles is used because MMR vaccines have been suspended due to the frequent occurrence of aseptic meningitis after their use. It is administered only once with the cover rate having been approximately 70%. An outbreak of measles was experienced in eight of our health care workers (three doctors, three nurses and two clerks of our hospital) and in seven of our medical students, accompanying local outbreaks. Their condition was severe enough to require admission to our school hospital. One of medical students developed encephalitis, but he has recovered completely. The social cost including medical cost per worker was approximately yen 500,000 (about $4,500). We measured antibodies against measles, rubella, chickenpox and mumps using the ELISA assay in 1048 health care workers less than 40 years of age and 99 medical students before their clinical practice two or three months after the outbreak. The cost including the measuring of antibodies and vaccination for these workers and students was approximately yen 2,800,000 and it will be yen 700,000 for new workers each year. The negative rates for workers were 1.2% for measles, 8.8% for rubella, 10.0% for mumps and 2.0% for chickenpox and those for the medical students were 1.0%, 22.0%, 9.0% and 5.0%, respectively. Of the workers, 9.6% who had more than the defined very high tiaer were thought to have subclinical reinfection because they were non-symptomatic. The rates were 1.2% for rubella, 0.5% for chickenpox and 0.0% for mumps for more than the defined high titers among the workers, suggesting a risk of outbreaks in the future. Therefore, the antibodies of health care workers and medical students should be measured at the hospital and the antibody-negative person should be vaccinated to prevent infection not only from their patients but also prevent other patients from becoming infected by contracted health care workers or students.

T-cell lines from 2 patients with adenosine deaminase (ADA) deficiency showed the restoration of ADA activity resulted from the reversion of an inherited mutation

Inherited deficiency of adenosine deaminase (ADA) results in one of the autosomal recessive forms of severe combined immunodeficiency. This report discusses 2 patients with ADA deficiency from different families, in whom a possible reverse mutation had occurred. The novel mutations were identified in the ADA gene from the patients, and both their parents were revealed to be carriers. Unexpectedly, established patient T-cell lines, not B-cell lines, showed half-normal levels of ADA enzyme activity. Reevaluation of the mutations in these T-cell lines indicated that one of the inherited ADA gene mutations was reverted in both patients. At least one of the patients seemed to possess the revertant cells in vivo; however, the mutant cells might have overcome the revertant after receiving ADA enzyme replacement therapy. These findings may have significant implications regarding the prospects for stem cell gene therapy for ADA deficiency.

Cerebral blood flow, glucose metabolism and tunel-positive cells in the development of ischemia

Few in vivo studies were available about the relation between cerebral blood flow, glucose metabolism and the appearance of apoptotic cells in the development of cerebral infarct. To investigate this, we measured local cerebral blood flow (lCBF), local cerebral metabolic rate in glucose (lCMRglc), and histopathology in transient focal cerebral ischemia in the rat. A unilateral middle cerebral artery occlusion (MCAO) was induced for 2 h in Wistar-ST rats (n = 42). A histopathological study with hematoxylin-eosin staining and the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) method was performed. lCBF was measured by means of the (14)C-iodoantipyrine autoradiography technique during MCAO (n = 6), and 1, 22 and 70 h after reperfusion. lCMRglc was also measured by autoradiography with (14)C-2-deoxyglucose in the animals 22 h after reperfusion. These parameters were assessed in each region of interest: the ischemic core, boundary zones (BZ-I and BZ-II) and remote area. The boundary zones were defined as the area based on TUNEL positivity (more than 5/field) at 22 h after reperfusion (BZ-I) and at 70 h after reperfusion (BZ-II). In the BZ-I, lCBF was decreased to 18% of the control during MCAO, and lCBF and lCMRglc showed 44 and 62% of the control, respectively, 22 h after reperfusion. In this area, TUNEL-positive cells increased at 22 h, then markedly decreased 70 h after reperfusion. In the BZ-II, lCBF decreased to 39% of the control during MCAO, then returned to about 90% of the control 22 h after reperfusion. lCMRglc was maintained near its normal range (82% of the control) 22 h after reperfusion. Histopathology of BZ-II was normal 22 h after reperfusion. The TUNEL positivity of neurons in our study was assumed to be a marker of apoptotic cells. Our data suggested that the apoptotic process plays an important role in the maturation of a cerebral infarct. Both lCBF and lCMRglc were maintained with only a mild reduction in the predisposing phase of apoptosis, suggesting that sufficient blood supply and glucose metabolism are required to promote the process of apoptosis.

Interaction of microcrystalline cellulose and water in granules prepared by a high-shear mixer

Microcrystalline cellulose (MCC) granules were prepared by wet granulation using a high-shear mixer. Physical characteristics of the granules were investigated using near IR spectrometry, thermogravimetry and isothermal water vapor adsorption. Near IR spectra of dried MCC granules prepared for various granulation times exhibited different peak intensities at 1428, 1772, and 1920 nm, which were assigned to functional groups of cellulose or water. On isothermogravimetric analysis, the rate of dehydration of water was shown to decrease with granulation time. These results suggest that the physical structure of MCC could change during the granulation process, and the interaction between MCC and water was gradually strengthened. The isothermal water vapor adsorption curves suggested that the amorphous region of MCC would be divided by the strong shear force of the impeller, because the high adsorption ability of intact MCC in the low humidity region was diminished in granules collected following 5 and 10 min of granulation. It was suggested that MCC formed a network which caught water within its structure during the wet granulation process.

hsp70-DnaJ chaperone pairs prevent nitric oxide-mediated apoptosis in RAW 264.7 macrophages

Excess nitric oxide (NO) induces apoptosis in some cell types, including macrophages. Heat shock protein of 70 kDa (hsp70) has been reported to protect cells from various stresses, including apoptosis-inducing stimuli. Several mammalian cytosolic DnaJ homologs, partner chaperones of hsp70 family members, have been identified. We asked if a DnaJ homolog is required to prevent NO-mediated apoptosis. When mouse macrophage-like RAW 264.7 cells were treated with an NO donor, SNAP, apoptosis occurred. This apoptosis could be prevented by pretreatment of the cells with heat or a low dose of SNAP. Under these conditions, levels of hsc70 (an hsp70 member) remained unchanged, whereas hsp70 was markedly induced. Of the DnaJ homologs dj1 (hsp40/hdj-1) was strongly induced and dj2 (HSDJ/hdj-2) was moderately induced. In transfection experiments, hsp70, hsc70, dj1 or dj2 alone was ineffective in preventing NO-mediated apoptosis. In contrast, both dj1 and dj2, in combination with hsc70 or hsp70, prevented the cells from apoptosis. The hsp70-DnaJ chaperone pairs exerted their anti-apoptotic effects upstream of caspase 3 activation, and apparently upstream of cytochrome c release from mitochondria.

Molecular properties of propranolol hydrochloride prepared as drug-resin complexes

Drug-resin complexes, as well as physical dispersions, containing varying contents of propranolol were prepared. The molecular properties of samples were investigated by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and infrared (IR) spectroscopy. In addition, the USP paddle method was used to determine the release behavior of drug from various formulations prepared from the samples. The data from DSC and XRPD indicated that the molecular state of drug in the complexes was amorphous, whereas that in the physical dispersions exhibited the crystalline state of pure drug. These results suggested that the molecule of drug prepared as drug-resin complexes was monomolecularly dispersed in the resin bead. The IR study provided evidence that demonstrated the interaction between the drug and resin in the complexes. The release behavior of drug from the complexes was governed by the cross-linkage structure and equilibrium treatment of drug exchange of resin.

Altered regulation of cell cycle machinery involved in interleukin-1-induced G(1) and G(2) phase growth arrest of A375S2 human melanoma cells

Interleukin-1 (IL-1) inhibits the growth of A375S2 human melanoma cells by arresting them at G(1) and G(2) phases of the cell cycle. The arrests are preceded by a rapid decrease in kinase activities of cyclin E-Cdk2 and cyclin B1-Cdc2, which are critical for G(1)-S and G(2)-M progression, respectively. IL-1 quickly enhances the protein expression of the CDK inhibitor p21(cip1). The induced p21 binds preferentially to cyclin E-Cdk2, and the increase in p21 binding parallels the decrease in cyclin E-Cdk2 activity. Thus, p21 is likely to be responsible for the inhibition of cyclin E-Cdk2 activity and G(1) arrest. Coinciding with the decrease in cyclin B1-Cdc2 activity, there is an increase in tyrosine phosphorylation of Cdc2, suggesting that an increase in the inactive Tyr-15-phosphorylated form of Cdc2 is involved in the decrease in cyclin B1-Cdc2 activity and G(2) arrest. Furthermore, we found that IL-1 causes rapid dephosphorylation of p107, but not of pRb or p130, while the total protein levels of p130 are increased. Thus, IL-1 may exert its growth-arresting effects via p107 and p130 pathways rather than through pRb.

A mutation of the Wilson disease protein, ATP7B, is degraded in the proteasomes and forms protein aggregates

BACKGROUND & AIMS

Wilson disease is a genetic disorder characterized by the accumulation of copper in the body as a result of a defect of copper excretion from hepatocytes. The intracellular localization of the Wilson disease gene product, ATP7B, was recently identified as the late endosomes. Various mutations have been documented in patients with Wilson disease. The clinical manifestations vary greatly among the patients; however, there is little information on the genotype-phenotype correlation.

METHODS

We investigated the distribution of a common ATP7B mutant His1069Gln and a mutant Asp1270Ser by expressing the mutants tagged with green fluorescent protein in Huh7 and HEK293 cells. Intracellular organelles were visualized by fluorescence microscopy.

RESULTS

Although the wild-type ATP7B and Asp1270Ser mutant localized in the late endosomes, His1069Gln mutant did not locate in the late endosomes and was degraded by the proteasomes in the cytoplasm. Furthermore, His1069Gln formed aggresomes composed of the degradates and intermediate filaments at the microtubule-organizing center. These aggresomes were similar to Mallory bodies on electron microscopy.

CONCLUSIONS

The different protein properties of ATP7B mutants may explain the variety of clinical spectrums in patients with Wilson disease.

Case-control study of ovarian cancer and polymorphisms in genes involved in catecholestrogen formation and metabolism

Steroid hormones, such as estrogens, appear to be associated with ovarian carcinogenesis, but the precise biological mechanisms are unclear. Polymorphisms in genes that regulate the concentration of estrogens and their metabolites may contribute directly to the individual variation in ovarian cancer risk through a mechanism involving oxidative stress or indirectly by influencing ovarian cancer susceptibility associated with ovulation and reproduction. We conducted a population-based, case-control study of primary ovarian cancer between 1993 and 1999 in Hawaii to test several genetic and related hypotheses. A personal interview and blood specimen were obtained in the subjects' homes. In a sample of 129 epithelial ovarian cancer cases and 144 controls, we compared the frequencies of several polymorphisms in genes that regulate steroid hormone metabolism and catecholestrogen formation. Multivariate unconditional logistic regression was used to model the association of each genetic polymorphism separately after adjusting for age, ethnicity, and other covariates. The high-activity Val432 allele of the CYP1B1 gene, which may be linked to oxidative stress through elevated 4-hydroxylated catecholestrogen formation, was associated with an increased risk of ovarian cancer. The Val/Leu genotype for CYP1B1 was associated with an odds ratio of 1.8 (95% confidence interval, 1.0-3.3) and the Val/Val genotype with an odds ratio of 3.8 (95% confidence interval, 1.2-11.4) compared with the Leu/Leu genotype (P = 0.005). Tobacco smokers with at least one CYP1A1 (MspI) m2 allele, one CYP1B1 Val allele, one COMT Met allele, or two CYP1A2 A alleles were at significantly increased risk of ovarian cancer compared to never-smokers with CYP1A1 (MspI) ml/ml, CYP1B1 Leu/Leu, COMT Val/Val, or CYP1A2 A/A genotypes, respectively. We found a positive statistical interaction (P = 0.03) between tobacco smoking and the CYP1A1 (MspI) polymorphism on the risk of ovarian cancer. None of the other gene-environment (pregnancy, oral contraceptive pill use) or gene-gene interactions were statistically significant. Although not significant, there was a suggestion that the effect of the CYP1B1 Val allele was reduced substantially in the presence of the high-activity COMT Met allele. These findings suggest that the CYP1B1-Val allele and perhaps other genetic polymorphisms in combination with environmental or hormonal exposures are susceptibility factors for ovarian cancer.

Molecular basis for paradoxical carriers of adenosine deaminase (ADA) deficiency that show extremely low levels of ADA activity in peripheral blood cells without immunodeficiency

Adenosine deaminase (ADA) deficiency causes an autosomal recessive form of severe combined immunodeficiency and also less severe phenotypes, depending to a large degree on genotype. In general, ADA activity in cells of carriers is approximately half-normal. Unexpectedly, healthy first-degree relatives of two unrelated ADA-deficient severe combined immunodeficient patients (mother and brother in family I; mother in family II) had only 1-2% of normal ADA activity in PBMC, lower than has previously been found in PBMC of healthy individuals with so-called "partial ADA deficiency." The level of deoxyadenosine nucleotides in erythrocytes of these paradoxical carriers was slightly elevated, but much lower than levels found in immunodeficient patients with ADA deficiency. ADA activity in EBV-lymphoblastoid cell lines (LCL) and T cell lines established from these carriers was 10-20% of normal. Each of these carriers possessed two mutated ADA alleles. Expression of cloned mutant ADA cDNAs in an ADA-deletion strain of Escherichia coli indicated that the novel mutations G239S and M310T were responsible for the residual ADA activity. ADA activity in EBV-LCL extracts of the paradoxical carriers was much more labile than ADA from normal EBV-LCL. Immunoblotting suggested that this lability was due to denaturation rather than to degradation of the mutant protein. These results further define the threshold level of ADA activity necessary for sustaining immune function.

Oxidative stress inhibits the mitochondrial import of preproteins and leads to their degradation

The mitochondrion depends upon the import of cytosolically synthesized preproteins for most of the proteins that comprise its structural elements and metabolic pathways. Here we have examined the influence of redox conditions on mitochondrial preprotein import and processing by mammalian mitochondria. Paraquat pretreatment of isolated mitochondria inhibited the subsequent import preornithine transcarbamylase (pOTC) in vitro. In intact cells oxidizing conditions led to decreased levels of mature OTC and accumulation of its preprotein. Implicating a mitochondrial import lesion, the fluorescence of pOTC-GFP (a protein in which the presequence of pOTC was fused to green fluorescent protein) transfected cells was decreased by paraquat treatment while cytosolic wild-type GFP remained largely unaffected. The accumulation of preproteins was enhanced by proteasome inhibitors. We observed that precursor proteins that failed to be imported, due to oxidizing conditions or an intrinsically slower import rate, are susceptible to degradation. Inhibition of the proteasome was also found to lead to higher levels of the translocase outer membrane protein 20 (Tom20) and to the perinuclear accumulation of mitochondria. These studies indicate that cellular redox conditions influence mitochondrial import, which, in turn, affects mitochondrial protein levels. A role for the proteasome in this process and in general mitochondrial function was also indicated.

Cell lineage analysis during liver development using the spf(ash)-heterozygous mouse

Biliary epithelial cells differentiate from periportal hepatoblasts during fetal mouse liver development. It remains to be determined whether each hepatoblast is equivalent for differentiation into hepatocytes and biliary epithelial cells in normal liver development. To resolve this question, the mosaic pattern of ornithine transcarbamylase (OTC) expression was analyzed in the hepatoblast population of spf(ash) (sparse-fur with abnormal skin and hair)-heterozygous fetal mouse livers, in which random inactivation of either the X chromosome carrying the spf(ash) gene (causing OTC deficiency) or its wild-type gene occurs. Aggregates (patches) of OTC-positive hepatoblasts showed very complex patterns, and their shapes and size distributions were similar in sections from periportal regions and nonperiportal regions of the fetal liver in which bile duct differentiation by periportal hepatoblasts occurred. Average sizes of periportal patches were larger than those of nonperiportal patches because of the presence of more hemopoietic cells in the latter region. The OTC mosaicism in periportal bile duct progenitors and hepatoblast islands of other liver parenchyma was also similar. These results suggest that the growth patterns of hepatoblasts are similar in both periportal and nonperiportal regions. Isolated three-dimensional patches comprising hepatoblasts giving rise to only biliary epithelial cells or hepatoblasts giving rise to both hepatocytes and biliary epithelial cells were observed in periportal regions. In nonperiportal regions, patches consisting of hepatoblasts differentiating into hepatocytes were also seen. Thus, it is likely that there are three lineages for the developmental fates of hepatoblasts: hepatoblasts giving rise to only biliary epithelial cells, hepatoblasts giving rise to only hepatocytes, and hepatoblasts giving rise to both of them.

[Comparison of cost and benefits of each model for rubella immunization in Japan]

MMR (measles-mumps-rubella) immunization in Japan was suspended in 1993 due to the high incidence of mumps meningitis as a complication. As a result, immunization coverage for rubella still remains at the 50-60% level in Japan. One way to increase the coverage rate is to increase the frequency of immunization. We calculated the predicted positivity rate of the antibody and cost and the benefits is three models of double vaccination, i.e., vaccination twice. The first model consists of simply two identical vaccinations. The second model consists of two vaccinations with mass vaccination at school for the second immunization. The third model consists of two vaccinations with screening of the urinary antibody for rubella in the second immunization. To calculate the predicted values we used coefficients from Ibara City. The predicted positivity rates and cost increases ranged from 60% to 90% and from 7.3 billion to 12.8 billion yen from the first to third models, respectively. Screening for the urinary antibody should be much cheaper than the presumed price because more than a million subjects will be screened. Since it would cost less than half the price, the third model should be best for the positivity rate of the antibody and cost and benefits. Therefore, we think that third model is the best correction until MMR immunization can be reintroduced.

[Genetic analysis of two patients with adenosine deaminase (ADA)-deficiency: detection of three novel mutations and characterization of two paradoxical carriers]

Genetic basis of two patients (AT, MT) with ADA deficiency was studied. We identified three novel mutations (119 Q-->Stop, 235 R-->Q, one base deletion in Exon 4) from the patients. 119 Q-->Stop was detected in AT and her father. Deletion of one base in Exon 4 which would change the reading frame after codon 105 H, was detected in MT, her father and brother. There was no relation between the two families, however, 235 R-->Q was also detected in both the patients and their mothers. Extremely low ADA activity of PBMCs was revealed in healthy MT's mother and brother just as MT, although their dAXP levels of RBCs showed significantly lower than that of MT. We defined that they shared an additional mutation (310 M-->T) together with the mutation described above, respectively. EBV-transformed B-cell line (EBV-B) were established from the carriers. To our surprise, ADA activity of their lines was 1/10-1/5 of normal. The result of heat treatment studies using the EBV-B showed that the mutant ADA rapidly lose its enzyme activity without degradation of the protein. It suggests that 310 M-->T mutant ADA rapidly lost its enzyme activity due to conformational change of the catalytic site of ADA.

Transvenous detachable coil embolization of direct & high-flow carotid-cavernous fistula. Alternative of transarterial detachable balloon embolization

SUMMARY

We encountered 8 cases of high-flow and direct carotid cavernous fistula (CCF) since 1994. Four patients were treated with transarterial fistula occlusions using detachable balloons before 1997. Complete obliteration of CCFs with preservation of internal carotid artery (ICA) were achieved in all 4 cases using each one balloon. Three cases were approached to the fistulas via the percutaneous transfemoral approach, but one aged patient needed a direct carotid puncture because of her tortuous vessels. Meanwhile, transvenous embolizations with detachable coils (DCs); Guglielmi detachable coil (GDC), interlocking detachable coil (IDC) and fibered platinum coil were attempted in four cases after 1997; in 2 cases after failure of transarterial approach and in 2 as initial form of treatment. All 4 cases were successfully approached to the cavernous sinuses (CS) through the inferior petorosal sinus (IPS). At first we intended to block dangerous outflow points for the superior ophthalmic vein (SOV), cortical venous reflux (CVR) and contra-lateral CS. And then obliteration of the fistulas were performed with tight packing of GDCs covering the outside of the ICA. At this time, the arteriovenous shunts were disappeared abruptly, so we finished all procedure without occlusion of IPS.We compared the two methods and concluded that the transvenous embolizaton with DCs is an useful alternative of transarterial detachable balloon therapy of high flow CCF, especially when transarterial approach is difficult or proper balloons are not available.

[mRNA detection of beta-myosin heavy chain gene in the autopsy cases of hypertrophic cardiomyopathy]

A known trigger of sudden cardiac death, hypertrophic cardiomyopathy (HCM) is associated with a point mutation in or overexpression of MYH7, which encodes the sarcomere protein beta-myosin heavy chain. We used nested RT-PCR to detect MYH7 mRNA in left ventricular myocardial tissue. We extracted total RNA from tissue samples that had been obtained after autopsy of 8 people who had died from HCM-related sudden death and that had been fixed in 10% formalin solution for as long as 4 years. The abundance of total RNA extracted from the 100 mg samples of cardiac muscle ranged from 10 to 24 mg/ml. The products of the nested RT-PCR were electrophoresed on a denaturing 8% polyacrylamide gel, and the MYH7 mRNA product was detected as a 424 bp band. MYH7 mRNA was easier to detect in tissue that had been fixed for shorter rather than longer periods. In addition, the greater the cardiac weight, the higher was the yield of the MYH7 mRNA product. Although mRNA had been detected by using RT-PCR on formalin-fixed paraffin-embedded tissue, no one previously had identified by using RT-PCR or nested RT-PCR on formalin-fixed tissue. By using nested RT-PCR, we were able to detect MYH7 mRNA in myocardial tissue that had been fixed in formalin solution for 4 years. Our results are applicable to retrospective examination into the cause of death in cases of sudden cardiac failure.

Somatosensory evoked high-frequency oscillations recorded directly from the human cerebral cortex

OBJECTIVE

To elucidate the generator sources of high-frequency oscillations of somatosensory evoked potentials (SEPs), we recorded somatosensory evoked high-frequency oscillations directly from the human cerebral cortex.

SUBJECTS AND METHODS

Seven patients, 6 with intractable partial epilepsy and one with a brain tumor, were studied. With chronically implanted subdural electrodes, we recorded SEPs to median nerve stimulation in all patients, and also recorded SEPs to lip and posterior tibial nerve stimulation in one. High-frequency oscillations were recorded using a restricted bandpass filter (500-2000 Hz).

RESULTS

For the median nerve oscillations, all oscillation potentials were maximum at the electrodes closest to the primary hand sensorimotor area. Most oscillations were distributed similar to or more diffusely than P20/N20. Some later oscillations after the peak of P20 or N20 were present in a very restricted cortical area similar to P25. We investigated the phase change of each oscillation potential around the central sulcus. One-third of the oscillations showed phase reversal around the central sulcus, while later oscillations elicited in a restricted cortical area did not. High-frequency oscillations to posterior tibial nerve and lip stimulation were also maximum in the sensorimotor areas. Most of the lip oscillations showed phase reversal around the central sulcus, but most of the posterior tibial nerve oscillations did not.

CONCLUSION

High-frequency oscillations are generated near the primary sensorimotor area. There are at least two different generator mechanisms for the median nerve high-frequency oscillations. We suspect that most oscillations are derived from the terminal segments of thalamocortical radiations or from the primary sensorimotor cortex close to the generator of P20/N20, and some later oscillations from the superficial cortex close to the generator of P25.

Functional analysis of human metaxin in mitochondrial protein import in cultured cells and its relationship with the Tom complex

Metaxin is an outer membrane protein of mammalian mitochondria which is suggested to be involved in protein import into the organelle. RNA blot analysis showed that distribution of metaxin mRNA in human tissues differs from that of mRNA for the translocase component Tom20. Effect of overexpression of human metaxin on mitochondrial preprotein import and processing in COS-7 cells was studied. Overexpression of metaxin resulted in impaired mitochondrial import of natural and chimeric preproteins and in their accumulation. We previously reported that overexpression of Tom20 in cultured cells causes inhibition of import of mitochondrial preprotein. Coexpression of metaxin with Tom20 had no further effect on the preprotein import. Overexpression of the cytosolic domain of metaxin also caused inhibition of preprotein import, although less strongly than the full-length metaxin. In blue native PAGE, Tom40, Tom22, and a portion of Tom20 migrated as a complex of approximately 400 kDa, and the other portion of Tom20 migrated in smaller forms of approximately 100 and approximately 40 kDa. On the other hand, metaxin migrated at a position of approximately 50 kDa. These results confirm earlier in vitro results that metaxin participates in preprotein import into mammalian mitochondria, and indicates that it does not associate with the Tom complex.

Identification and functional analysis of human Tom22 for protein import into mitochondria

Mitochondria have a receptor complex in the outer membrane which recognizes and translocates mitochondrial proteins synthesized in the cytosol. We report here the identification and functional analysis of human Tom22 (hTom22). hTom22 has an N-terminal negatively charged region exposed to the cytosol, a putative transmembrane region, and a C-terminal intermembrane space region with little negative charge. Tom22 forms a complex with Tom20, and its cytosolic domain functions as an import receptor as in fungi. An import inhibition assay, using pre-ornithine transcarbamylase (pOTC) derivatives and a series of hTom22 deletion mutants, showed that the C-terminal segment of the cytosolic domain is important for presequence binding, whereas the N-terminal domain is important for binding to the mature portion of pOTC. No evidence for pOTC interaction with the Tom22 intermembrane space domain was obtained. Binding studies revealed that the presequence is critical for pOTC binding to Tom20, whereas both the presequence and mature portion are important for binding to Tom22. A cell-free immunoprecipitation assay indicated that an internal segment of the Tom22 cytosolic domain is important for interaction with Tom20.

Desynchronization and synchronization of central 20-Hz rhythms associated with voluntary muscle relaxation: a magnetoencephalographic study

To clarify the cortical mechanisms involved in motor inhibition, modulation of cortical rhythms around 20 Hz during voluntary muscle relaxation was compared to that during muscle contraction in ten normal volunteers, using a whole head type neuromagnetometer. Each subject relaxed or contracted the right forearm muscles, from which electromyograms were recorded. After bandpass filtering magnetoencephalographic signals into frequency bands of 6-10, 10-14, 14-18, 18-22, 22-26, and 26-30 Hz, the signals of each frequency band were rectified and averaged with respect to the onset of motor trial. The relaxation task showed movement-related 20-Hz desynchronization over bilateral central areas beginning a few seconds before the termination of muscle contraction. Twenty-hertz desynchronization was present also for the contraction task at the same location within each subject. The two tasks had a positive correlation among subjects in both the percent decrease (r2=0.76, P<0.01) and the peak time (r2=0.61, P<0.05) for the contralateral 20-Hz desynchronization. After the muscle relaxation, desynchronization was followed by conspicuous movement-related synchronization of the 20-Hz passband in the contralateral central areas, which was significantly larger than that after the contraction (P<0.001). The results suggest that the voluntary muscle relaxation involves the modulation of central rhythms starting a few seconds before the actual event, and the 20-Hz desynchronization has a similar temporal property in the muscle relaxation and contraction. The 20-Hz synchronization in the contralateral central area after the muscle relaxation may be associated with the temporally arrayed termination of the ongoing muscle contraction.

Low induction of varicella-zoster virus-specific secretory IgA antibody after vaccination

Breakthrough after varicella vaccination occurs in approximately 2. 6% approximately 18.6% of immunocompetent children, but the reason has not been demonstrated clearly. As a first defense, specific secretory IgA antibody on the mucosa plays an important role in preventing invasion of microorganisms. To examine induction of varicella-zoster virus (VZV) specific secretory IgA after natural infection and vaccination and its booster mechanisms, 143 salivary samples were tested by ELISA. The VZV-secretory IgA values were significantly higher in the matched children after natural chickenpox than in those after vaccination, although the total secretory IgA did not differ between them. Two (7%) of the vaccinees lacked the sIgA antibody. In the elderly and in immunocompromised children, the VZV-secretory IgA values were no lower than those in healthy children, and they did not lack VZV-secretory IgA. The doctors and nurses taking care of patients with chickenpox had higher values than the other groups as did individuals who had had herpes zoster recently. VZV-secretory IgA was thought to be stimulated by exogenous and reactivated endogenous VZV to neutralize VZV with weak activity. These results suggest that low or no induction of VZV-secretory IgA antibody after vaccination may be one of the possible explanations for a breakthrough.

Quantitative correlation between initial dissolution rate and heat of fusion of drug substance

The initial dissolution rates of amorphous, partial crystalline and crystalline samples of terfenadine polymorphs (forms I and II) were measured by the rotating disk method. The heats of fusion due to crystalline fraction of samples were obtained by the differential scanning calorimetry (DSC) data taking into account the heat of crystallization and the heat capacity change at glass transition during the heating process. The logarithms of initial dissolution rates of different crystallinity samples were linearly correlated with the corrected heats of fusion, irrespective of the crystal forms.

Human DnaJ homologs dj2 and dj3, and bag-1 are positive cochaperones of hsc70

DnaJ is an essential cochaperone of mammalian heat shock cognate 70 (hsc70) protein. We previously found that dj2 (HSDJ/hdj-2/rdj1), rather than dj1 (hsp40/hdj-1), is a partner DnaJ for the hsc70-based chaperone system. Here, we compared the distribution of dj1, dj2, and the newly found dj3 (cpr3/DNJ3/HIRIP4/rdj2) in cultured cells. Both dj3 as well as dj2 were farnesylated and were ubiquitously expressed. In immunocytochemical and subfractionation studies, these two proteins colocalized with hsc70 under normal conditions. However, dj1 and hsc70 apparently colocalized in the nucleoli after heat shock. Simultaneous depletion of dj2 and dj3 from rabbit reticulocyte lysate markedly reduced mitochondrial import of pre-ornithine transcarbamylase and refolding of guanidine-denatured luciferase. Re-addition of either dj2 or dj3 led to recovery of these reactions. In a reconstituted system, both hsc70-dj2 and hsc70-dj3 were effective in protein refolding. Anti-apoptotic protein bag-1 further stimulated ATP hydrolysis and protein refolding by both pairs. Thus, dj2 and dj3 are the partner DnaJs of hsc70 within the cell, functionally similar and much more efficient than dj1, and bag-1 is a positive cochaperone of the hsc70-dj2 and hsc70-dj3 systems.