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Biomedical subjects

M Maki

Publications and source records attributed to M Maki.

At least 127 records · Page 7Linked to original sources
PubMed1991

Structure of the active 27-residue fragment of human calpastatin.

A synthetic 27-residue peptide corresponding to exon 1B of the endogenous inhibitor calpastatin contains a well-conserved region and has an ability to inhibit the cysteine endopeptidase calpain specifically. We examined the solution structure of this peptide in DMSO-d6 by two-dimensional 1H NMR spectroscopy. Although regular secondary structures such as alpha-helix and beta-sheet were not found, the region from Ile18 to Arg23 formed a well-defined structure with a type I beta-turn. This region coincided well with the highly conserved region of calpastatin. The result strongly suggests that this turn structure is essential for the inhibitory activity of calpastatin.

Amino Acid Sequence↗
PubMed1991

Functional conversion from HIV-1 Rev to HTLV-1 Rex by mutation.

A nucleolar localizing rev gene mutant M10 of human immunodeficiency virus type 1 (HIV-1) lost a Rev function completely, instead, gained a Rex activity of human T cell leukemia virus type 1 (HTLV-1). The obtained compatibility between Rev M10 and Rex with their own nucleolar targeting signal (NOS) suggests a common molecular mechanism of their post-transcriptional regulation, despite no sequence similarities of both proteins and their responsive RNA elements, respectively.

Amino Acid Sequence↗
PubMed1991

Direct measurement of calpastatin subtypes by sandwich enzyme immunoassay using monoclonal antibodies.

Six stable hybridoma cell lines secreting monoclonal antibodies to human calpastatin were established. All monoclonal antibodies belong to the IgG1 subclass and recognized different epitopes on calpastatin. At least two groups were distinguished; the first group was specific for muscle-type (M-) calpastatin and the second group recognized not only M-calpastatin but also erythrocyte-type (E-) calpastatin. The inhibitory effect of all monoclonal antibodies on calpastatin activity was relatively low even at high concentrations of antibodies. Enzyme immunoassay systems were developed for direct determination of calpastatin subtypes in human cells requiring no other sample treatment than the disruption of the cells. The assay methods were, in principle, based on the sandwich enzyme immunoassay using epitope-specific monoclonal antibodies. The enzyme immunoassay system for M-calpastatin was specific for M-calpastatin and could not detect E-calpastatin. The enzyme immunoassay system for total calpastatin detected not only M-calpastatin but also E-calpastatin. The sensitivity of these assay systems was 10 pmol l-1 of calpastatins. Antigenicity of calpastatins was found to be unchanged in the presence of EDTA and haemoglobin. Good reproducibilities of within-and between-assay series and excellent recovery of exogenous calpastatins from cell lysates were observed. From these results, it seems that our newly developed subtype-specific enzyme immunoassay systems for calpastatins are useful in biochemical studies and clinical testing for determination of calpastatin subtypes.

Antibodies, Monoclonal↗
PubMed1991

Effects of chimeric mutants of human immunodeficiency virus type 1 Rev and human T-cell leukemia virus type I Rex on nucleolar targeting signals.

Two chimeric mutant genes derived from rev of human immunodeficiency virus type 1 and rex of human T-cell leukemia virus type I were constructed to investigate the functions of the nucleolar-targeting signals (NOS) in Rev and Rex proteins. A chimeric Rex protein whose NOS region was substituted with the NOS of Rev was located predominantly in the cell nucleolus and functioned like the wild-type protein in the Rex assay system. However, a chimeric Rev with the NOS of Rex abolished Rev function despite its nucleolar localization. This nonfunctional nucleolar-targeting chimeric protein inhibited the function of both Rex and Rev. In the same experimental conditions, this mutant interfered with the localization of the functional Rex in the nucleolus.

Amino Acid Sequence↗
PubMed1991

The relationship between clinical signs and hypercoagulable state in toxemia of pregnancy.

The hypercoagulable state in patients with toxemia of pregnancy was investigated in comparison with normal pregnant women using new coagulation parameters, mainly thrombin-antithrombin III (TAT) complexes, alpha 2-antiplasmin-plasmin complexes (PIP), and D-dimer FDP. When the patients were categorized by the classification of the WHO Study Group (1985), significant increases of TAT complexes and alpha 2-PIP complexes with decreases of the ATIII level were observed in the groups with preeclampsia and severe gestational hypertensive disease as compared to normal pregnant women. A significant increase of D-dimer FDP was observed in a group with severe gestational hypertensive disease. Additionally, the relationship between clinical signs and the hypercoagulable state in the patients was analyzed using canonical correlation analysis as a multivariate analysis. The clinical signs and coagulation parameters had a significantly high correlation of lambda 1 = 0.7219, p less than 0.01. The results showed that clinical signs were associated with simultaneous coagulation abnormalities. The indices obtained from the results of canonical correlation analysis, which were called the clinical index and the coagulation index, should be useful in evaluating the efficacy of anticoagulation therapy.

Adult↗
PubMed1991

Relationship between the duration of fetal breathing movements and gestational age and the development of the central nervous system at 25-32 weeks of gestation in normal pregnancy.

In 15 pregnant women with normal pregnancy at 25-32 weeks of gestation, fetal breathing movements (FBM), fetal body movements and fetal heart rate were continuously and simultaneously recorded over a total period of 180 min. The frequency of successive FBM with a duration less than 10 s (apnea period greater than 3 s) showed a significant decrease (p less than 0.01), while the frequency of successive FBM with a duration greater than or equal to 30 s showed a significant increase from 25 to 32 weeks of gestation (p less than 0.001). Strong positive correlations were also demonstrated between the frequency of FBM with a duration of greater than or equal to 30 s and the number of fetal heart rate accelerations per hour, acceleration/fetal body movement ratio, and the value of fetal heart rate long-term variability. These results suggest that the length of the duration of successive FBM represents a useful parameter for the analysis of fetal respiratory patterns, and that a prolongation of the duration of successive FBM of an individual fetus is related to the functional development of the central nervous system.

Central Nervous System↗
PubMed1991

Relationship of fetal breathing movement pattern to surfactant phospholipid levels in amniotic fluid and postnatal respiratory complications.

Fetal breathing patterns in 102 patients delivering before 37 weeks of gestation were divided into three types by the duration of successive respiratory activity using an ultrasonic scanner. Approximately 80% of the fetuses with fetal breathing absent or less than 9 s developed neonatal respiratory complications, including 11 cases of severe RDS and 8 cases of apnea of prematurity. However, no infant showing breathing activity of 30 s or more in utero experienced severe respiratory complications after birth. Furthermore, the surfactant phospholipid concentration in amniotic fluid was significantly increased with prolongation of successive fetal breathing activity. These results suggest that the duration of successive fetal breathing movements closely relates with fetal lung development including biochemical and neuromuscular systems in the humans, i.e. functional maturation of the fetal respiratory system, and also that prenatal analysis of breathing patterns may permit evaluation of pulmonary functional capacity after birth.

Amniotic Fluid↗
PubMed1991

Phospholipid-binding properties of calphobindin-II(annexin VI), anticoagulant protein from human placenta.

Calphobindin-II (CPB-II, annexin VI), is a calcium dependent phospholipid binding protein that can be classified as a member of the annexin family. The phospholipid-binding properties of CPB-II were investigated by measuring the binding constants of [125I]-CPB-II using phospholipid vesicles consisting of 80% phosphatidylcholine and 20% phosphatidylserine. A dissociation constant (Kd) of CPB-II with the phospholipid vesicles was determined to be 0.2 to 0.3 nM in the presence of Ca2+ ranging from 0.3 to 30 mM. The number of CPB-II capable of binding to the phospholipid vesicles at 0.3 mM Ca2+ decreased to about 1/2 in the presence of Ca2+ of more than 1 mM. Prothrombin and factor X were effective in competing with the binding of CPB-II to the phospholipid vesicles, although their affinities were lower by two or three orders of magnitude than that of unlabeled CPB-II at 30 nM Ca2+. Competitive effects of CPB-II, calphobindin-I (CPB-I, annexin V) and calphobindin-III (CPB-III, annexin III) on binding of [125I]-CPB-II to phospholipid vesicles, were similarly observed.

Annexin A6↗
PubMed1991

Dietary sodium concentration modifies catecholamine release with stress in spontaneously hypertensive rats.

A high sodium diet increased the plasma norepinephrine (PNE) only in resting spontaneously hypertensive rats (SHR). SHR on either a high or low sodium diet showed a greater increase in arterial pressure (AP) than Wistar-Kyoto rats (WKY) with foot shock (FS). However, neither a high nor low sodium diet enhanced the increment of AP in both SHR and WKY with FS. Only a low sodium diet enhanced the increment of PNE and plasma epinephrine in SHR with FS. Extreme restriction of sodium intake might thus enhance the response of sympathetic activation with stressful stimuli.

Animals↗
PubMed1991

The impact of experience with AIDS on HIV testing and counseling practices: a study of U.S. infectious disease teaching hospitals and Minnesota hospitals.

A survey on HIV antibody testing practices was sent to the 200 hospitals in the United States that conduct infectious disease (ID) fellowship training and to all 171 short-term care Minnesota hospitals. Responses were obtained from 124 U.S. ID hospitals (62%) and from 133 (78%) Minnesota hospitals. The U.S. ID hospitals estimated that consent for HIV antibody testing is obtained 70.1% of the time, that consent is both obtained and documented 54.3% of the time, and that risk-reduction counseling in conjunction with such testing is provided 51.4% of the time. The Minnesota hospitals estimated that consent for HIV antibody testing is obtained 35.2% of the time, that consent is both obtained and documented 25.7% of the time, and that risk-reduction counseling in conjunction with such testing is provided 21.8% of the time. Wide variance was noted in both the U.S. and Minnesota responses. Those U.S. hospitals serving higher numbers of persons with AIDS gave higher estimates for each of the 3 items (p less than .05); similar findings were noted among the Minnesota hospitals. The data suggests that standard clinical use of HIV testing remains deficient.

AIDS Serodiagnosis↗
PubMed1991

Molecular diversity of erythrocyte calpastatin.

According to the difference of molecular masses estimated by SDS-polyacrylamide gel electrophoresis, calpastatins are classified into two types, i.e. muscle type (110 kDa) and erythrocyte type (70 kDa). Muscle type calpastatin contains four internally repetitive sequences (Domains 1-4) and one nonhomologous sequence on the amino-terminal side (Domain L), whereas erythrocyte type lacks Domains L and 1. By immuno-blot analysis, chicken erythrocytes, nucleated cells, were found to contain muscle type calpastatin. In avian erythrocytes, diminution of the calpastatin molecule as in mammalian erythrocytes was not observed.

Animals↗
PubMed1991

The influence of experimentally produced oligohydramnios on lung growth and pulmonary surfactant content in fetal rabbits.

To study the effect of oligohydramnios on lung growth and biochemical lung development in fetal rabbits, amniotic fluid was drained through a tube inserted into the maternal peritoneal cavity on the 23 day of gestation. Littermate fetuses without an amniotic shunt were used as controls. The fetuses were delivered abdominally on the 28 day of gestation. In a total of 8 pregnant does, 17 fetuses underwent amniotic shunting and 22 fetuses were used as controls. The amniotic shunt produced a significant reduction in the amniotic fluid volume. There were no differences in the wet weights of the fetal body, liver or brain between the two groups. However, the amniotic shunt significantly decreased the wet weight of the fetal lung, fetal lung wet weight/body weight ratio, and protein concentration per lung as compared to the control fetuses. In the fetal liver and brain tissues, no changes were found in the concentrations of total phospholipids, phosphatidylcholine (PC) or disaturated phosphatidylcholine (DSPC, the main component of lung surfactant) per g of wet tissue and per mg of protein. However, the lungs of the fetuses with amniotic shunts contained significantly more PC and DSPC, and the L/S ratio was higher than in the control fetuses. These results suggest that the oligohydramnios produced by an amniotic shunt causes pulmonary hypoplasia, but raises the pulmonary surfactant content of fetal rabbit lung.

Animals↗
PubMed1991

AIDS-related knowledge, attitudes, and behaviors among 629 registered nurses at a Minnesota hospital: a descriptive study.

Since nurses play a pivotal role in many aspects of healthcare delivery, their knowledge, attitudes, and behavior in relation to AIDS are crucial. A descriptive study was done to discover the AIDS-related knowledge, attitudes, and behavior among registered nurses who practice in a hospital setting, and to describe the relationship of these findings with other variables. A 67-item survey was sent to 704 registered nurses at a 455-bed acute care teaching hospital and its associated clinics. The results indicated there is a considerable level of misinformation, mistrust, and fear regarding AIDS among RNs practicing in the hospital setting.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Clinical effect of low molecular weight heparin (fragmin) on DIC: a multicenter cooperative study in Japan.

A multicenter cooperative study was carried out involving 47 nationwide institutes in Japan to assess the efficacy and safety of low molecular weight heparin (Fragmin) on DIC. Fifty-six DIC cases were challenged by Fragmin injection principally for 5 days with the doses of 75 U/kg/day in the I group (n = 27) and 150 U/kg/day in the II group (n = 29). Scoring points were defined based on the severity of bleeding symptoms, organ failures and abnormal coagulation-fibrinolytic examinations, and therapeutic effect of Fragmin was evaluated objectively according to the improvement degrees of these scores. Six cases (10.7%) died of the underlying diseases or complications other than DIC and hemorrhagic side effects occurred in 3.7 and 10.3% cases of the I and II groups, respectively. However, in bleeding symptoms, 45.5 and 31.6% cases of the I and II groups improved excellently or moderately. In organ failures and coagulation-fibrinolytic examinations, remarkable improvement was observed in 31.6 and 66.7% cases of the I group, while they remained 14.3 and 51.7% in the II group, respectively. The overall utility of Fragmin was 66.7% in the I group and 58.6% in the II group. These results demonstrate that Fragmin is effective on DIC with a dose of 75 U/kg/day.

Adult↗
PubMed1990

Soluble factors including proteinases released from damaged cells may trigger the wound healing process.

The wound healing process is initiated as soon as tissue is injured. Herein, we demonstrate that c-fos and c-myc mRNA transcripts are promptly increased in the wounded tissue in vivo and in vitro. A buffer solution from scraped serum-starved quiescent fibroblasts, when added to resting fibroblasts, caused the increase of c-fos and c-myc mRNA among the indicator cells. Soluble factors contained in the wounding supernatant are responsible for these phenomena and we call them wounding factors. Addition of proteinase inhibitors to the culture medium drastically reduced the c-fos mRNA induction by the wounding factors. Exogenously added trypsin or thrombin mimicked the activity of wounding factors. These results suggest that wounding causes soluble factors including various proteinases to be released from the damaged cells, which trigger the adjacent cells to respond to the injury.

Animals↗
PubMed1990

Characterization of a functional domain of human calpastatin.

Expression plasmids were constructed from the cDNA of human calpastatin to examine the contribution to the inhibition of calpain of highly conserved sequences in each of four repetitive domains. A series of deletion derivatives of domain 1 proteins, truncated at either the amino or carboxy terminus, were produced in E. coli. Deletion from the amino terminus past the amino terminal conserved sequence decreased the inhibition. When the middle conserved sequence, the M-sequence, was further deleted, no inhibition was detected, but deletion from the carboxy terminus past the carboxy terminal conserved sequence did not decrease the inhibition until the M-sequence was reached. Nuclear magnetic resonance and circular dichroism spectra showed that domain 1 has an unfolded structure. Peptides that contained the M-sequence and some neighboring sequences were synthesized to measure the minimum size of the inhibitory peptide, which was the M-sequence with the next six residues on the amino terminal side.

Amino Acid Sequence↗