Confronting the Challenge of Modeling Cloud and Precipitation Microphysics

In the atmosphere, microphysics refers to the microscale processes that affect cloud and precipitation particles and is a key linkage among the various components of Earth's atmospheric water and energy cycles. The representation of microphysical processes in models continues to pose a major challenge leading to uncertainty in numerical weather forecasts and climate simulations. In this paper, the problem of treating microphysics in models is divided into two parts: (i) how to represent the population of cloud and precipitation particles, given the impossibility of simulating all particles individually within a cloud, and (ii) uncertainties in the microphysical process rates owing to fundamental gaps in knowledge of cloud physics. The recently developed Lagrangian particle-based method is advocated as a way to address several conceptual and practical challenges of representing particle populations using traditional bulk and bin microphysics parameterization schemes. For addressing critical gaps in cloud physics knowledge, sustained investment for observational advances from laboratory experiments, new probe development, and next-generation instruments in space is needed. Greater emphasis on laboratory work, which has apparently declined over the past several decades relative to other areas of cloud physics research, is argued to be an essential ingredient for improving process-level understanding. More systematic use of natural cloud and precipitation observations to constrain microphysics schemes is also advocated. Because it is generally difficult to quantify individual microphysical process rates from these observations directly, this presents an inverse problem that can be viewed from the standpoint of Bayesian statistics. Following this idea, a probabilistic framework is proposed that combines elements from statistical and physical modeling. Besides providing rigorous constraint of schemes, there is an added benefit of quantifying uncertainty systematically. Finally, a broader hierarchical approach is proposed to accelerate improvements in microphysics schemes, leveraging the advances described in this paper related to process modeling (using Lagrangian particle-based schemes), laboratory experimentation, cloud and precipitation observations, and statistical methods.

Hyperthermophilic and salt-dependent formyltransferase from Methanopyrus kandleri

Methanopyrus kandleri is a hyperthermophilic methanogenic archaeon, which grows on H(2) and CO(2) as its sole energy source. Its growth temperature optimum is 98 degrees C. One of the interesting characteristics of this archaeon is its high intracellular salt content. The organism has been reported to contain the trianionic cDPG (cyclic 2,3-diphosphoglycerate) and K+ at concentrations of 1.1 and 3 M, respectively. Reflecting the high cellular salt concentration, the enzymes in this organism are adapted not only to high temperature but also to high salt concentrations. The formyltransferase from M. kandleri was characterized extensively with respect to thermo- and halophilicity. The crystal structure of the formyltransferase at 1.73 A shows the enzyme to be composed of four identical subunits of molecular mass 32 kDa. The formyltransferase is thermostable and active only at relatively high concentrations of potassium phosphate (1 M) or other salts with strongly hydrated anions (strong salting-out salts). Potassium phosphate and potassium cDPG were found to be equivalent in activating and stabilizing the enzyme. At low concentrations of these salts, the enzyme is inactive and thermolabile. It was shown by equilibrium sedimentation analysis that the enzyme is in a monomer/dimer/tetramer equilibrium, the equilibrium constant being dependent on the concentration of salts: the higher oligomeric species increase with increasing salt concentrations. Evidence was provided that the monomer is both inactive and thermolabile. Experiments using a mutation which is directed to break surface ion pairs between two dimers indicated that dimerization is required for activity and tetramerization leads to thermostability.

Characterization of a heme-dependent catalase from Methanobrevibacter arboriphilus

Recently it was reported that methanogens of the genus Methanobrevibacter exhibit catalase activity. This was surprising, since Methanobrevibacter species belong to the order Methanobacteriales, which are known not to contain cytochromes and to lack the ability to synthesize heme. We report here that Methanobrevibacter arboriphilus strains AZ and DH1 contained catalase activity only when the growth medium was supplemented with hemin. The heme catalase was purified and characterized, and the encoding gene was cloned. The amino acid sequence of the catalase from the methanogens is most similar to that of Methanosarcina barkeri.

On the mechanism of biological methane formation: structural evidence for conformational changes in methyl-coenzyme M reductase upon substrate binding

Methyl-coenzyme M reductase (MCR) catalyzes the final reaction of the energy conserving pathway of methanogenic archaea in which methylcoenzyme M and coenzyme B are converted to methane and the heterodisulfide CoM-S-S-CoB. It operates under strictly anaerobic conditions and contains the nickel porphinoid F430 which is present in the nickel (I) oxidation state in the active enzyme. The known crystal structures of the inactive nickel (II) enzyme in complex with coenzyme M and coenzyme B (MCR-ox1-silent) and in complex with the heterodisulfide CoM-S-S-CoB (MCR-silent) were now refined at 1.16 A and 1.8 A resolution, respectively. The atomic resolution structure of MCR-ox1-silent describes the exact geometry of the cofactor F430, of the active site residues and of the modified amino acid residues. Moreover, the observation of 18 Mg2+ and 9 Na+ ions at the protein surface of the 300 kDa enzyme specifies typical constituents of binding sites for either ion. The MCR-silent and MCR-ox1-silent structures differed in the occupancy of bound water molecules near the active site indicating that a water chain is involved in the replenishment of the active site with water molecules. The structure of the novel enzyme state MCR-red1-silent at 1.8 A resolution revealed an active site only partially occupied by coenzyme M and coenzyme B. Increased flexibility and distinct alternate conformations were observed near the active site and the substrate channel. The electron density of the MCR-red1-silent state aerobically co-crystallized with coenzyme M displayed a fully occupied coenzyme M-binding site with no alternate conformations. Therefore, the structure was very similar to the MCR-ox1-silent state. As a consequence, the binding of coenzyme M induced specific conformational changes that postulate a molecular mechanism by which the enzyme ensures that methylcoenzyme M enters the substrate channel prior to coenzyme B as required by the active-site geometry. The three different enzymatically inactive enzyme states are discussed with respect to their enzymatically active precursors and with respect to the catalytic mechanism.

Laparoscopic-assisted hepatectomy (LAH) for the treatment of hepatocellular carcinoma

The treatment of hepatocellular carcinoma associated with liver cirrhosis necessitates local therapy in some patients because of severe hepatic dysfunction. Percutaneous ethanol injection therapy, the local therapy for such cancer of the liver, and percutaneous microwave coagulation therapy are detailed. The significant disadvantages of these procedures is their inability to evaluate precisely whether the tumor will develop complete necrosis after treatment because the cancer tissue cannot be excised with use of these procedures. Conversely, laparoscopic hepatectomy, which is minimally invasive surgery, has a disadvantage, that is, its difficulty in complex maneuvers, including hemostasis, ligation, and suture. The authors developed laparoscopic-assisted hepatectomy, which is hepatectomy by small incision during laparotomy with the use of laparoscopic observation. This report describes laparoscopic-assisted hepatectomy, which may allow the solving of problems with percutaneous ethanol injection therapy, percutaneous microwave coagulation therapy, and laparoscopic hepatectomy.

The metal-free hydrogenase from methanogenic archaea: evidence for a bound cofactor

The hmd gene, which encodes the metal-free hydrogenase in methanogenic archaea, was heterologously expressed in Escherichia coli. The overproduced enzyme was completely inactive. High activity could, however, be induced by the addition of ultrafiltrate from active enzyme denatured in 8 M urea. The active fraction in the ultrafiltrate was heat-labile and migrated on gel filtration columns with an apparent molecular mass well below 1000 Da.

A mutation affecting the association equilibrium of formyltransferase from the hyperthermophilic Methanopyrus kandleri and its influence on the enzyme's activity and thermostability

Formyltransferase from Methanopyrus kandleri is composed of only one type of subunit of molecular mass 32 kDa. The enzyme is in a monomer/dimer/tetramer association equilibrium, the association constant being affected by lyotropic salts. Oligomerization is required for enzyme activity and thermostability. We report here on a subunit interface mutation (R261E) which affects the dimer/tetramer part of the association equilibrium of formyltransferase. With the mutant protein it was shown that tetramerization is not required for activity but is necessary for high thermostability.

Comparison of three methyl-coenzyme M reductases from phylogenetically distant organisms: unusual amino acid modification, conservation and adaptation

The nickel enzyme methyl-coenzyme M reductase (MCR) catalyzes the terminal step of methane formation in the energy metabolism of all methanogenic archaea. In this reaction methyl-coenzyme M and coenzyme B are converted to methane and the heterodisulfide of coenzyme M and coenzyme B. The crystal structures of methyl-coenzyme M reductase from Methanosarcina barkeri (growth temperature optimum, 37 degrees C) and Methanopyrus kandleri (growth temperature optimum, 98 degrees C) were determined and compared with the known structure of MCR from Methanobacterium thermoautotrophicum (growth temperature optimum, 65 degrees C). The active sites of MCR from M. barkeri and M. kandleri were almost identical to that of M. thermoautotrophicum and predominantly occupied by coenzyme M and coenzyme B. The electron density at 1.6 A resolution of the M. barkeri enzyme revealed that four of the five modified amino acid residues of MCR from M. thermoautotrophicum, namely a thiopeptide, an S-methylcysteine, a 1-N-methylhistidine and a 5-methylarginine were also present. Analysis of the environment of the unusual amino acid residues near the active site indicates that some of the modifications may be required for the enzyme to be catalytically effective. In M. thermoautotrophicum and M. kandleri high temperature adaptation is coupled with increasing intracellular concentrations of lyotropic salts. This was reflected in a higher fraction of glutamate residues at the protein surface of the thermophilic enzymes adapted to high intracellular salt concentrations.

Protection of Methanosarcina barkeri against oxidative stress: identification and characterization of an iron superoxide dismutase

Methanosarcina barkeri is a methanogenic archaeon that can only grow under strictly anoxic conditions but which can survive oxidative stress. We have recently reported that the organism contains a monofunctional catalase. We describe here that it also possesses an active iron superoxide dismutase. The enzyme was purified in three steps over 130-fold in a 14% yield to a specific activity of 1500 U/mg. SDS-PAGE revealed the presence of only one band, at an apparent molecular mass of 25 kDa. The primary structure determined from the cloned and sequenced gene revealed similarity to iron- and manganese superoxide dismutases. The highest similarity was to the iron superoxide dismutase from Methanobacterium thermoautotrophicum. The enzyme from M. barkeri was found to contain, per mol, 1 mol iron, but no manganese in agreement with the general observation that anaerobically growing organisms only contain iron superoxide dismutase. The enzyme was not inhibited by cyanide (10 mM), which is a property shared by all iron- and manganese superoxide dismutases. The presence of superoxide dismutase in M. barkeri is noteworthy since a gene encoding superoxide dismutase (sod) has not been found in Archaeoglobus fulgidus, a sulfate-reducing archaeon most closely related to the Methanosarcinaceae.

Structure of coenzyme F(420) dependent methylenetetrahydromethanopterin reductase from two methanogenic archaea

Coenzyme F(420)-dependent methylenetetrahydromethanopterin reductase (Mer) is an enzyme of the Cl metabolism in methanogenic and sulfate reducing archaea. It is composed of identical 35-40 kDa subunits and lacks a prosthetic group. The crystal structure of Mer from Methanopyrus kandleri (kMer) revealed in one crystal form a dimeric and in another a tetrameric oligomerisation state and that from Methanobacterium thermoautotrophicum (tMer) a dimeric state. Each monomer is primarily composed of a TIM-barrel fold enlarged by three insertion regions. Insertion regions 1 and 2 contribute to intersubunit interactions. Insertion regions 2 and 3 together with the C-terminal end of the TIM-barrel core form a cleft where the binding sites of coenzyme F(420) and methylene-tetrahydromethanopterin are postulated. Close to the coenzyme F(420)-binding site lies a rarely observed non-prolyl cis-peptide bond. It is surprising that Mer is structurally most similar to a bacterial FMN-dependent luciferase which contains a non-prolyl cis-peptide bond at the equivalent position. The structure of Mer is also related to that of NADP-dependent FAD-harbouring methylenetetrahydrofolate reductase (MetF). However, Mer and MetF do not show sequence similarities although they bind related substrates and catalyze an analogous reaction.

The biosynthesis of methylated amino acids in the active site region of methyl-coenzyme M reductase

The global production of the greenhouse gas methane by methanogenic archaea reaches 1 billion tons per annum. The final reaction releasing methane is catalyzed by the enzyme methyl-coenzyme M reductase. The crystal structure of methyl-coenzyme M reductase from Methanobacterium thermoautotrophicum revealed the presence of five modified amino acids within the alpha-subunit and near the active site region. Four of these modifications were C-, N-, and S-methylations, two of which, 2-(S)-methylglutamine and 5-(S)-methylarginine, have never been encountered before. We have now confirmed these modifications by mass spectrometry of chymotryptic peptides. With methyl-coenzyme M reductase purified from cells grown in the presence of L-[methyl-D(3)]methionine, it was shown that the methyl groups of the modified amino acids are derived from the methyl group of methionine rather than from methyl-coenzyme M, an intermediate in methane formation. The D(3) labeling pattern was found to be qualitatively and quantitatively the same as in the two methyl groups of the methanogenic coenzyme F(430), which are known to be introduced via S-adenosylmethionine. From the results, it is concluded that the methyl groups of the modified amino acids in methyl-coenzyme M reductase are biosynthetically introduced by an S-adenosylmethionine-dependent post-translational modification. A mechanism for the methylation of glutamine at C-2 and of arginine at C-5 is discussed.

The crystal structure of methenyltetrahydromethanopterin cyclohydrolase from the hyperthermophilic archaeon Methanopyrus kandleri

BACKGROUND

The reduction of carbon dioxide to methane in methanogenic archaea involves the tetrahydrofolate analogue tetrahydromethanopterin (H(4)MPT) as a C(1) unit carrier. In the third step of this reaction sequence, N(5)-formyl-H(4)MPT is converted to methenyl-H(4)MPT(+) by the enzyme methenyltetrahydromethanopterin cyclohydrolase. The cyclohydrolase from the hyperthermophilic archaeon Methanopyrus kandleri (Mch) is extremely thermostable and adapted to a high intracellular concentration of lyotropic salts.

RESULTS

Mch was crystallized and its structure solved at 2.0 A resolution using a combination of the single isomorphous replacement (SIR) and multiple anomalous dispersion (MAD) techniques. The structure of the homotrimeric enzyme reveals a new alpha/beta fold that is composed of two domains forming a large sequence-conserved pocket between them. Two phosphate ions were found in and adjacent to this pocket, respectively; the latter is displaced by the phosphate moiety of the substrate formyl-H(4)MPT according to a hypothetical model of the substrate binding.

CONCLUSIONS

Although the exact position of the substrate is not yet known, the residues lining the active site of Mch could be tentatively assigned. Comparison of Mch with the tetrahydrofolate-specific cyclohydrolase/dehydrogenase reveals similarities in domain arrangement and in some active-site residues, whereas the fold appears to be different. The adaptation of Mch to high salt concentrations and high temperatures is reflected by the excess of acidic residues at the trimer surface and by the higher oligomerization state of Mch compared with its mesophtic counterparts.

Longitudinal relationship between maternal depression and infant temperament in a Japanese population

To investigate the relationship between maternal depression and infant temperament in a Japanese population, a prospective questionnaire survey was administered in the postpartum period. Postnatal depression was assessed by Zung's (1965) Self-Rating Depression Scale on two occasions (5 days and 12 months after delivery). At 6 months and 18 months after birth, infant temperament was assessed using the Revised Infant Temperament Questionnaire (RITQ; Carey & McDevitt, 1978) and the Toddler Temperament Scale (TTS; Fullward, McDevitt, & Carey, 1984), respectively. Of the five temperamental dimensions of the RITQ and TTS, "rhythmicity" and "attention span and persistence" showed reciprocal relationships with postnatal depression. Unidirectional effects of maternal depression on infant temperament were found for "frustration tolerance" and "fear of strangers and strange situations."

Structure of depressive symptoms in pregnancy and the postpartum period

BACKGROUND

The present study investigated the structure of depressive symptoms in the perinatal period.

METHOD

The Zung Self-Rating Depression Scale (SDS) was administered to a total of 1329 women in early, middle and late pregnancy and 5 days, 1 month, 6 months, 12 months and 18 months after the delivery.

RESULTS

A number of somatic items and the suicidal ideation item of the SDS made low contributions to the evaluation of the severity of depression, and as a consequence these were excluded in the principal component analysis. Three factors were interpretable as "Cognitive", "Affective insomnia" and "Attentional" emerged at all eight assessment points. The goodness-of-fit index (GFI) generated by confirmatory factor analyses (LISREL 7.20) proved sufficiently high on all eight occasions.

LIMITATION

The present study investigated only one self-rating scale and the sample comprised Japanese mothers only.

CONCLUSION

The three-factor model of the SDS in the perinatal period was derived from exploratory and confirmatory factor analyses. It is noteworthy that the same three-factor structure emerged at all eight collection points in the present study.

Temporal variation of validity of self-rating questionnaires: improved validity of repeated use of Zung's Self-Rating Depression Scale among women during the perinatal period

It has been reported that Zung's Self-Rating Depression Scale (SDS) loses its validity in predicting cases of depression when used repeatedly. The validity of SDS was tested against the subject's Research Diagnostic Criteria (RDC) diagnoses of major/minor depressive disorders in 120 pregnant women four times throughout the perinatal period. Different sets of predictive SDS items were found at different time points. We developed an 'RDC-like' algorithm from SDS items. Though varying in sensitivity, we found that this formula yielded low, but stable, positive predictive values and constantly high negative predictive values. We suggest that the RDC-like algorithm is a better alternative for screening depression among perinatal women.

Purification, characterization, and primary structure of a monofunctional catalase from Methanosarcina barkeri

Methanosarcina barkeri is a strictly anaerobic, cytochrome-containing, methane-forming archaeon. We report here that the microorganism contains a catalase, which was purified and characterized. The enzyme with an apparent molecular mass of 190 kDa was shown to be composed of four identical subunits of apparent molecular mass of 54 kDa. The heme-containing enzyme did not exhibit peroxidase activity, which indicates that it is a monofunctional catalase. This is substantiated by the primary structure, which is related to that of other monofunctional catalases rather than to that of bifunctional catalase-peroxidases. The enzyme showed an [S]0.5V for H2O2 of 25 mM and an apparent Vmax of 200,000 U/mg; it was inhibited by azide ([I]0.5V = 1 microM) and cyanide ([I]0.5V = 5 microM) and inactivated by 1,2,4-aminotriazole. The activity was almost independent of the pH (between pH 4 and 10) and the temperature (between 15 degrees C and 55 degrees C). Comparison of the primary structure of monofunctional catalases revealed that the enzyme from M. barkeri is most closely related to the monofunctional catalase of Dictyostelium discoideum.

Psychiatric disorders among Japanese children

OBJECTIVE

To generate current data on the prevalence of psychiatric disorders among Japanese children, using DSM-III-R criteria.

METHOD

As part of an ongoing longitudinal study in a Japanese community sample, 114 mother-child dyads were interviewed when the children were approximately 8 years old. DSM-III-R disorders of the children were diagnosed through the administration of a structured diagnostic instrument, the parent and child versions of the Child Assessment Schedule, to both the children and their mothers.

RESULTS

The prevalence rate for any diagnosis was 49.1%, which is similar to that of U.S. children and adolescents.

CONCLUSION

The Child Assessment Schedule is an appropriate scale for assessing the psychopathology of Japanese children, which is as prevalent as in a U.S. sample.

Active sites of transition-metal enzymes with a focus on nickel

Since 1995, crystal structures have been determined for many transition-metal enzymes, in particular those containing the rarely used transition metals vanadium, molybdenum, tungsten, manganese, cobalt and nickel. Accordingly, our understanding of how an enzyme uses the unique properties of a specific transition metal has been substantially increased in the past few years. The different functions of nickel in catalysis are highlighted by describing the active sites of six nickel enzymes - methyl-coenyzme M reductase, urease, hydrogenase, superoxide dismutase, carbon monoxide dehydrogenase and acetyl-coenzyme A synthase.

Lyotropic-salt-induced changes in monomer/dimer/tetramer association equilibrium of formyltransferase from the hyperthermophilic Methanopyrus kandleri in relation to the activity and thermostability of the enzyme

Formyltransferase from Methanopyrus kandleri is composed of only one type of subunits of molecular mass 32 kDa. The enzyme requires the presence of lyotropic salts for activity and thermostability. We report here that the enzyme is in a monomer/dimer/tetramer association equilibrium, the association constant being affected by lyotropic salts. At 0.01 M K2HPO4/KH2PO4, pH 7.2, the enzyme (0.4 mg/ml) was mainly present in a monomeric form. Upon increase of the phosphate concentration, the concentration of the dimer increased up to a phosphate concentration of 0.6 M, then decrease at the expense of tetramer formation up to a phosphate concentration of 1.0 M. The specific activity at 4 C increased from <0.1 U/mg at 0.01 M, over 1.5 U/mg at 0.6 M to 3.6 U/mg at 1.0 M. Similar results were obtained with ammonium sulfate as lyotropic salt. The findings indicate that both oligomerization and activity increase with increasing salt concentrations, suggesting that there is a causal connection. To determine this, we exploited the observation that oligomer formation was not induced by the weak lyotropic salt NaCl up to a concentration of 1.5 M and that the dissociation of the dimer into the monomer at 4 degrees C proceeded very slowly (50% in approximately 6 h). This allowed us to study the effect of NaCl on the activity of the oligomers at NaCl concentrations not sufficient to induce oligomerization. At 4 degrees C, the activity of the oligomers increased from 0.3 U/mg at 0.25 M NaCl to 3.4 U/mg at 1.0 M NaCl. At these NaCl concentrations, the monomers were inactive. The findings indicate that oligomerization is a prerequisite for enzyme activity in the presence of NaCl. The salt-dependent induction of oligomerization was parallelled by an increase in thermostability; strong lyotropic salts conferred thermostability at much lower concentrations than the weak lyotropic NaCl.

Activation and thermostabilization effects of cyclic 2, 3-diphosphoglycerate on enzymes from the hyperthermophilic Methanopyrus kandleri

Enzymes involved in methane formation from carbon dioxide and dihydrogen in Methanopyrus kandleri require high concentrations (> 1 M) of lyotropic salts such as K2HPO4/KH2PO4 or (NH4)2SO4 for activity and for thermostability. The requirement correlates with high intracellular concentrations of cyclic 2,3-diphosphoglycerate (cDPG; approximately 1 M) in this hyperthermophilic organism. We report here on the effects of potassium cDPG on the activity and thermostability of the two methanogenic enzymes cyclohydrolase and formyltransferase and show that at cDPG concentrations prevailing in the cells the investigated enzymes are highly active and completely thermostable. At molar concentrations also the potassium salts of phosphate and of 2,3-bisphosphoglycerate, the biosynthetic precursor of cDPG, were found to confer activity and thermostability to the enzymes. Thermodynamic arguments are discussed as to why cDPG, rather than these salts, is present in high concentrations in the cells of Mp. kandleri.

Single and repeated elective abortions in Japan: a psychosocial study

Despite its social, legal and medical importance, termination of pregnancy (TOP) (induced abortion) has rarely been the focus of psychosocial research. Of a total of 1329 women who consecutively attended the antenatal clinic of a general hospital in Japan, 635 were expecting their first baby. Of these 635 women, 103 (16.2%) had experienced TOP once previously (first aborters), while 47 (7.4%) had experienced TOP two or more times (repeated aborters). Discriminant function analysis was performed using psychosocial variables found to be significantly associated with either first abortion or repeated abortion in bivariate analyses. This revealed that both first and repeated aborters could be predicted by smoking habits and an unwanted current pregnancy while the repeated aborters appear to differ from first aborters in having a longer pre-marital dating period, non-arranged marriages, smoking habits, early maternal loss experience or a low level of maternal care during childhood. These findings suggest that both the frequency of abortion and its repetition have psychosocial origins.

Relationship of order and number of siblings to perceived parental attitudes in childhood

Despite the increasingly recognized link between perceived parenting behavior and the onset of psychopathology in adults, studies of the possible determinants of perceptions of parenting behavior are rare. In a sample of 1,145 pregnant Japanese women, correlations were examined between the numbers and sexes of siblings and perceived rearing practices, as rated by the Parental Bonding Instrument (PBI; Parker, Tupling, & Brown, 1979). The participants with more elder sisters viewed their parents' attitudes as less caring, whereas those with more brothers, particularly younger brothers, viewed their parents' attitudes as less overprotective. However, the proportion of the variance of all the PBI scores explained by different types of siblings was very small.

Social support and pregnancy: I. Factorial structure and psychosocial correlates of perceived social support

In a questionnaire survey among 1329 first-trimester pregnant women, social support providers were divided by factor analysis into husband, 'premarital network' (parents and friends) and 'postmarital network' (children and mother-in-law), while social support contents were divided into 'given' (emotional, informational and instrumental support) and 'giving' (nurturing opportunity and general confiding). The husband was most frequently nominated by the woman as the support provider in both of these categories. Multiple regression analyses revealed that a husband's poor 'given' support was predicted by the presence of premenstrual irritability, a lower level of the woman's own education, her smoking habits and past experience of pregnancy termination, while a husband's poor 'giving' support was predicted by current older age, smoking habits and past experience of delivery.

Social support and pregnancy: II. Its relationship with depressive symptoms among Japanese women

In a questionnaire survey among 1329 first-trimester pregnant women, both the husband support measures and unwanted pregnancy ('stressor' agent in pregnancy) showed significant effects on an elevated score of the cognitive disturbance subscale of the Zung's self-rating depression scale (SDS), while only unwanted pregnancies showed an effect on an elevated score of the dysphoric mood subscale of the SDS. However, no interaction was observed between the husband support measures and unwanted pregnancy, therefore the effect of the husband's social support on the cognitive disturbance score was not that of a buffer, but rather a main effector. Finally, multiple regression analyses showed that the dysphoric mood score was preceded by unwanted pregnancy, premenstrual irritability, public self-consciousness, and maternal overprotection; while the cognitive disturbance score was preceded by unwanted pregnancy, husband reduced 'given' and 'giving' support, maternal reduced care and overprotection, paternal reduced care, low annual income, low private self-consciousness, and smoking. These findings suggest that the husband's support for a pregnant woman is effective only in reducing cognitive symptoms, and that different symptomatic constellations have different sets of psychosocial correlates.

Crystal structure of methyl-coenzyme M reductase: the key enzyme of biological methane formation

Methyl-coenzyme M reductase (MCR), the enzyme responsible for the microbial formation of methane, is a 300-kilodalton protein organized as a hexamer in an alpha2beta2gamma2 arrangement. The crystal structure of the enzyme from Methanobacterium thermoautotrophicum, determined at 1.45 angstrom resolution for the inactive enzyme state MCRox1-silent, reveals that two molecules of the nickel porphinoid coenzyme F430 are embedded between the subunits alpha, alpha', beta, and gamma and alpha', alpha, beta', and gamma', forming two identical active sites. Each site is accessible for the substrate methyl-coenzyme M through a narrow channel locked after binding of the second substrate coenzyme B. Together with a second structurally characterized enzyme state (MCRsilent) containing the heterodisulfide of coenzymes M and B, a reaction mechanism is proposed that uses a radical intermediate and a nickel organic compound.

The influence of beryllium on cell survival rates in theIn-vitro culture system, on intracellular DNA synthesis and on SRBC-IgM antibody production responses

Immunocytotoxicity of beryllium (Be) was evaluated by studying cell viability, intracellular DNA synthesis and SRBC-IgM response in an in-vitro culture system using non-sensitized spleen cells of a C57BL mouse. Be addition showed a suppressive effect on cell viability, an enhancing effect on DNA synthesis and on IgM antibody production. The suppressive effect on cell viability manifested itself markedly as the concentration of Be was increased or the culture time was prolonged. The DNA synthesis-enhancing effect was noted at a relatively low concentration of Be (not more than 10μM). The enhancing effect on the IgM response was related to Be concentration at not more than 20μM. The experimental results mentioned above speculate that the cytotoxicity of Be shows a conflicting pattern of enhancement or suppression according to the concentration used and that immunologically it has a modulating effect or an activating effect on the immunocompetent cells.

eaeA genes in Escherichia coli derived from Japanese patients with sporadic diarrhea

To investigate the prevalence of attaching and effacing Escherichia coli, we examined 364 strains isolated from the feces of 9,684 patients with diarrhea at the Anjo Kosei Hospital in Japan for the presence of eaeA. Twenty-nine (8%) of the strains were eaeA positive. Of enteropathogenic E. coli (EPEC), 11 of the 87 (13%) strains were for the positive eaeA gene. The serotypes and the numbers of eaeA-positive strains among the strains tested were as follows: O26:H-(2/3), O55:H7 (4/4), O55:H-(2/ 2) and O128:H2(3/3). Two enterohemorrhagic E. coli (EHEC) strains (Verotoxin positive O157:H7) were also eaeA positive. Among 260 non-EPEC strains that were not categorized as diarrheagenic E. coli, 16 (6%) were eaeA positive. Those serotypes were as follows: O15:H2, O20:H6, O28:H28, O63:H6. O153:H7, O28:H6, O153:H19 and O157:H45. EPEC strains including O18:H7 and six other serotypes, enteroinvasive E. coli (EIEC), and enterotoxigenic E. coli (ETEC) were all eaeA negative.

A study on the beryllium lymphocyte transformation test and the beryllium levels in working environment

The relationship between airborne concentration of beryllium in the working environment and workers' beryllium lymphocyte transformation test (Be-LTT) values was examined based on data obtained from a four-year survey (1992-1995) conducted at beryllium-copper alloy manufacturing factories. This study showed that the T cells of workers continuously exposed to beryllium of more than 0.01 microgram/m3 could be activated and that the cell-mediated immune response of workers could be promoted. On the other hand, the Be-LTT of workers exposed to beryllium levels of less than 0.01 microgram/m3 was shown to be unaffected by beryllium. These findings suggest that beryllium sensitization is not manifested when level of beryllium in working environment are less than 0.01 microgram/m3. Therefore, in such cases workers do not develop Chronic beryllium disease (CBD). We concluded that the Be-LTT can be applied as a medical indicator to detect the development of CBD.

Formylmethanofuran: tetrahydromethanopterin formyltransferase from Methanopyrus kandleri - new insights into salt-dependence and thermostability

BACKGROUND

Formylmethanofuran: tetrahydromethanopterin formyltransferase (Ftr) from the methanogenic Archaeon Methanopyrus kandleri (optimum growth temperature 98 degrees C) is a hyperthermophilic enzyme that is absolutely dependent on the presence of lyotropic salts for activity and thermostability. The enzyme is involved in the pathway of carbon dioxide reduction to methane and catalyzes the transfer of formyl from formylmethanofuran to tetrahydromethanopterin.

RESULTS

The crystal structure of Ftr, determined to a resolution of 1:73 AE reveals a homotetramer composed essentially of two dimers. Each subunit is subdivided into two tightly associated lobes both consisting of a predominantly antiparallel beta sheet flanked by alpha helices forming an alpha/beta sandwich structure. The approximate location of the active site was detected in a region close to the dimer interface.

CONCLUSIONS

The adaptation of Ftr against high lyotropic salt concentrations is structurally reflected by a large number of negatively charged residues and their high local concentration on the surface of the protein. The salt-dependent thermostability of Ftr might be explained on a molecular basis by ionic interactions at the protein surface, involving both protein and inorganic salt ions, and the mainly hydrophobic interactions between the subunits and within the core.

Crystallization and preliminary X-ray diffraction studies of methyl-coenzyme M reductase from methanobacterium thermoautotrophicum

Methyl-coenzyme M reductase isoenzyme I from the methanogenic Archaeon, Methanobacterium thermoautotrophicum (strain Marburg), was crystallized by vapor diffusion methods. Crystal form M obtained with 2-methyl-2,4-pentanediol as the precipitant displayed space group P2(1), with unit cell parameters of a=83.2 A, b=117.4 A, c=125.1 A, and beta= 92.6 degrees, and diffracted at better than 2.8 A resolution. Crystal form P grown from polyethylene glycol 400 belonged to space group P2(1), and had unit cell parameters of a=83.1 A, b=120.2 A, c=123.1 A, and beta=91.7 degrees, diffracting at least to 1.7 A resolution. Both crystal forms have one molecule per asymmetric unit and are suitable for X-ray structure analysis.

Premenstrual mood changes and maternal mental health in pregnancy and the postpartum period

To investigate the relationship between premenstrual mood changes and maternal mental health in the perinatal period, a prospective questionnaire survey of 1,329 women was carried out. Women with a premenstrual mood changes (irritability) before pregnancy showed significantly higher Zung's Self-rating Depression Scale (SDS) scores than those without it, throughout pregnancy and the postpartum period (6 time points: early, middle, and late pregnancy, 5 days, 1 month, and 6 months after childbirth). In addition, women with premenstrual irritability had greater anxiety about pregnancy and delivery, were more reluctant to accept mother roles, and felt their babies (fetuses or neonates) were more vulnerable. These findings suggest that premenstrual mood change is correlated with unstable mental health throughout the perinatal period.

The efficacy of antidepressants in post-stroke depression

The aim of the present study was to confirm the efficacy of antidepressants in post-stroke depression and to identify the factors related to outcome. Subjects consisted of 20 inpatients suffering from post-stroke in a rehabilitation hospital. The subjects were treated with various antidepressants, mainly imipramine, amitriptyline, and amoxapine. After 4 weeks of treatment, 13 showed some improvement; significant improvement in 5, moderate improvement in 5, mild improvement in 3 by a clinical global impression. Whereas all the patients aged less than 65 yr were responders, only 3 of the 10 patients over 65 yr were responders. All of the male patients, but only half of the female patients, were responders. With regards to the presence of a spouse, 13 of the 16 patients with a spouse, but none of 4 patients without, showed a response. No significant correlation was found between the occurrence of each depressive symptom and outcome. Thus, the responders were younger and had better social support in comparison with the non-responders. This result implies that antidepressants are effective for post-stroke depression.

[Availability of the Alcohol Use Disorders Identification Test (AUDIT) for a complete health examination in Japan]

OBJECTIVE

The Alcohol Use Disorders Identification Test (AUDIT) is an instrument designed to identify hazardous drinkers, harmful drinkers and alchoholics. It was translated into Japanese using the WHOQOL method. The concurrent validity and reliability of the Japanese version of AUDIT were evaluated in a complete health examination. The instrument was also compared with the CAGE questionnaire.

METHOD

The subjects were 93 applicants attending for health checks in a human dry dock. They completed self-report questionnaires containing the Core AUDIT and CAGE. and underwent a semi-structured interview conducted by a professional physician.

RESULT

From the semi-structured interview, it was determined that 23 of the subjects were problem drinkers and 10 were alcoholics. Analyses indicated that the Core AUDIT was sufficiently sensitive and specific for discriminating problem drinkers and alcoholics. Core AUDIT was also superior to CAGE for discriminating problem drinkers from non-problem drinkers, as well as identifying alcoholics.

CONCLUSION

The data suggest that the Japanese version of AUDIT is useful for early detection of hazardous or harmful drinkers.

Crystallization and preliminary X-ray diffraction studies of formylmethanofuran: tetrahydromethanopterin formyltransferase from Methanopyrus kandleri

Formylmethanofuran:tetrahydromethanopterin formyltransferase from the hyperthermophilic methanogenic Archaeon Methanopyrus kandleri (growth temperature optimum 98 degrees C) was crystallized by vapor diffusion methods. Crystal form M obtained with 2-methyl-2,4-pentanediol as precipitant displayed the space group P2(1) with unit cell parameters of a = 87.0 A, b = 75.4 A, c = 104.7 A, and beta = 113.9 degrees and diffracted better than 2 A resolution. Crystal form P grown from polyethylene glycol 8000 belonged to the space group I4(1)22 and had unit cell parameters of 157.5 A and 242.1 A. Diffraction data to 1.73 A were recorded. Crystal form S which was crystallized from (NH4)2SO4 in the space group I4(1)22 with unit cell parameters of 151.3 A and 249.5 A diffracted at least to 2.2 A resolution. All crystal forms probably have four molecules per asymmetric unit and are suitable for X-ray structure analysis.

Psychosocial study of depression in early pregnancy

BACKGROUND

The psychosocial correlates of depression during pregnancy were explored.

METHOD

Pregnant women attending the antenatal clinic of a general hospital (n = 1329) received a set of questionnaires including Zung's Self-Rating Depression Score (SDS). SDS high scores (> 49) (the cases: n = 179) were compared with low scores (< 38) (the controls; n = 343).

RESULTS

The cases were characterised by: first delivery; more nausea, vomiting, and anorexia; more menstrual pains and premenstrual irritability; early paternal loss; lower maternal care and higher paternal overprotection; higher public self-consciousness score; more smoking and use of medication in pregnancy; unwanted pregnancy; negative psychological response to the pregnancy by the woman and husband; poor intimacy by the husband; and having remarried.

CONCLUSIONS

Depression in early pregnancy is determined mainly by psychosocial factors.

Primary structure and properties of the formyltransferase from the mesophilic Methanosarcina barkeri: comparison with the enzymes from thermophilic and hyperthermophilic methanogens

The ftr gene encoding formylmethanofuran: tetrahydromethanopterin formyltransferase (Ftr) from Methanosarcina barkeri was cloned, sequenced, and functionally expressed in Escherichia coli. The overproduced enzyme was purified eightfold to apparent homogeneity, and its catalytic properties were determined. The primary structure and the hydropathic character of the formyltransferase from Methanosarcina barkeri were compared with those of the enzymes from Methanobacterium thermoautotrophicum, Methanothermus fervidus, and Methanopyrus kandleri. The amino acid sequence of the enzyme from Methanosarcina barkeri was 64%, 61%, and 59% identical to that of the enzyme from Methanobacterium thermoautotrophicum, Methanothermus fervidus, and Methanopyrus kandleri, respectively. A negative correlation between the hydrophobicity of the enzymes and both the growth temperature optimum and the intracellular salt concentration of the four organisms was observed. The hydrophobicity of amino acid composition was +21.6 for the enzyme from Methanosarcina barkeri (growth temperature optimum 37 degrees C, intracellular salt concentrationapproximately 0.3 M), +9.9 for the enzyme from Methanobacterium thermoautotrophicum (65 degrees C,approximately 0.7 M), -20.8 for the enzyme from Methanothermus fervidus (83 degrees C,approximately 1.0 M) and -31.4 for the enzyme from Methanopyrus kandleri (98 degrees C, > 1.1 M). Generally, a positive correlation between hydrophobicity and thermophilicity of enzymes and a negative correlation between hydrophobicity and halophilicity of enzymes are observed. The findings therefore indicate that the hydropathic character of the formyltransferases compared is mainly determined by the intracellular salt concentration rather than by temperature. Sequence similarities between the formyltransferases from methanogens and an open reading frame from Methylobacterium extorquens AM1 are discussed.

Adenoid cystic carcinoma of the esophagus: report of a case and review of the Japanese literature

We report herein the case of a 79-year-old man with adenoid cystic carcinoma (ACC) of the esophagus. The tumor had a polypoid appearance and was covered by thin esophageal mucosa. As the biopsy specimens suggested a diagnosis of poorly differentiated adenocarcinoma, the patient underwent subtotal esophagectomy with reconstruction of the gastric tube via the posterior mediastinum. Histologically, the carcinoma contained basaloid cells, cribriform foci, and a certain amount of eosinophilic hyaline substance. Some of the basaloid cells were stained immunohistochemically for keratin, muscle actin, and S-100 protein, a pattern which was identical to the pattern of immunoreactivity of the myoepithelium. We reviewed 36 other cases of ACC of the esophagus reported in Japan, with special reference to the criteria for histological diagnosis.

Clinical and psychosocial correlates of antenatal depression: a review

In contrast to the considerable research on postnatal depression, less attention has been paid to that occurring during pregnancy-antenatal depression (AD). However, recent investigations have studied depression among pregnant women not necessarily requiring psychiatric hospitalization but needing psychological support and help. A controlled study showed that the rate of AD was significantly higher than that of depression among non-pregnant women: the reported incidence varies between 4 and 29%. AD was found to be associated with: (1) obstetric factors (first pregnancy, first delivery, and past history of abortion); (2) early experience (loss of father); (3) personality (high neuroticism score); (4) attitudes towards the present pregnancy (perplexity of the husband); (5) accomodation factors (non-detached housing, and expected crowdedness after birth of the child, and (6) social support (low level of intimacy with the husband). Differential effects of these factors in the development of AD are to be studied in future research, particularly in conjunction with investigation of hormonal variables.