Use of FM1-43, a membrane-specific fluorescent dye, to estimate plasma membrane integrity in the cryopreservation of green algae.

BACKGROUND AND OBJECTIVE: Cryopreservation of microorganism cultures is an important technology for their use as biological and genetic resources; however, the procedure is complicated and depends on the species. MATERIALS AND METHODS: We used the two-step freezing method for the cryopreservation of the green alga Parachlorella kessleri. RESULTS AND CONCLUSION: The optimal cryoprotectant for cryopreservation was 5% dimethyl sulfoxide plus 5% ethylene glycol. This is different from the optimal cryoprotectant for the closely related species Chlorella vulgaris. Efficient cryopreservation of P. kessleri was achieved using methanol, similar to Chlamydomonas reinhardtii. A membrane-specific fluorescent dye, FM1-43, was applied to estimate plasma membrane integrity. We found that the plasma membrane integrity of P. kessleri cells after freeze-thawing was associated with survivability, suggesting that this is a useful index for the optimization of the first step of the two-step freezing method of cryopreservation.

Fluorine diffusion assisted by diffusing silicon on the Si(111)-(7x7) surface.

The diffusion process of fluorine (F) atoms on the Si(111)-(7x7) surface is investigated using high-temperature scanning tunneling microscopy. The kinetic parameters of F hopping agree well with those of the diffusing silicon (Si) atoms, which implies that of all reaction processes, the Si diffusion serves as the rate-determining one. Deposition of Si on the surface is found to enhance F hopping, which supports the above-mentioned observation. Theory reveals that the replacement of F adsorption sites by diffusing Si atoms is the key process in the diffusion mechanism.

Transfusions of CPDA-1 red blood cells stored for up to 28 days decrease donor exposures in very low-birth-weight premature infants.

The goal of this research was to study the safety and the efficacy of transfusing citrate-phosphate-adenine anticoagulant-preservative (CPDA-1) RBC stored for up to 28 days to reduce donor exposures in premature infants. A prospective randomized two-group study was conducted with very low-birth-weight premature infants that received at least one RBC transfusion during hospital stay. Neonates randomly assigned to Group 1 (26 infants) were transfused with CPDA-1 RBC stored for up to 28 days; those assigned to Group 2 (26 infants) received CPDA-1 RBC stored for up to 3 days. Demographic and transfusion-related data were collected. Neonates from both groups showed similar demographics and clinical characteristics. The number of transfusions per infant transfused was 4.4 +/- 4.0 in Group 1 and 4.2 +/- 3.1 in Group 2, and the number of donors per infant transfused was 1.5 +/- 0.8 (Group 1) and 4.3 +/- 3.4 (Group 2), P < 0.001. RBC transfusions containing 29.7 +/- 18.3 mmol L(-1) of potassium (RBC stored for up to 28 days) did not cause clinical or biochemical changes and reduced donor exposures by 70.2%, compared to transfusions containing 19.8 +/- 12.3 mmol L(-1) of potassium (RBC stored for up to 3 days), P < 0.001. In conclusion, RBC stored for up to 28 days safely reduced donor exposures in premature infants.

Allelic polymorphisms of human fcgamma receptor IIa and Fcgamma receptor IIIb among distinct groups in Brazil.

BACKGROUND: The FcgammaRIIA gene is expressed in two polymorphic forms, R131 and H131, which differ by the replacement of histidine by arginine at position 131. The FCGR3B (FcgammaRIIIB) gene exists in two allelic isoforms, known as FCGR3B1 (FcgammaRIIIB-NA1) and FCGR3B2 (FcgammaRIIIB-NA2), which differ in nucleotides 141, 147, 227, 277, and 349. An additional polymorphism is the SH antigen that is associated with the FCGR3B3 (FcgammaRIIIB-SH) allele. STUDY DESIGN AND METHODS: By use of a PCR with allele-specific primers, the allelic polymorphisms of FcgammaRIIA and FcgammaRIIIB were determined among 263 unrelated Brazilian subjects, including Amazon Indians (n = 92), blood donors (n = 85), and patients with sickle cell disease (SCD) (n = 86). RESULTS: Amazon Indians had a significantly higher frequency of the R131 allele than did blood donors and SCD patients (0.91 vs. 0.55 vs. 0.55; p<0.001). NA1 and NA2 gene frequencies were found to be 0.67 and 0.21 for Amazon Indians, 0.58 and 0.42 for blood donors, and 0.61 and 0.39 for SCD patients, respectively. The FcgammaRIIIB-SH allele was absent from the Amazon Indians, but 9 (10.6%) blood donors and 10 (11.6%) SCD patients expressed this allele. CONCLUSION: Overall, the data indicate that the distribution of the FcgammaRIIIB alleles is significantly different in Amazon Indians from the distribution in Brazilian blood donors or African Brazilian patients with SCD, but that it is similar to the distributions reported in Asian populations. Moreover, the distribution of the FcgammaRIIA and FcgammaRIIIB alleles among Brazilian blood donors and SCD patients is comparable to the distributions reported in whites from the United States and Europe.

Platelet alloantigen frequencies in Amazon Indians and Brazilian blood donors.

The frequencies of human platelet-specific alloantigens (HPAs) vary between different ethnic groups, and genotyping using DNA techniques has been preferred over immunophenotyping methods for population studies. Using a polymerase chain reaction with allele-specific primers (PCR-ASP) method, we determined the allelic polymorphisms of five HPA systems among 174 unrelated individuals of two different Brazilian ethnic groups including Amazon Indians (n = 95) and blood donors (n = 79). Comparison of the calculated gene frequencies of the two alleles of HPA-1, -2, -3, -4 and -5 systems for Amazon Indians and Brazilian blood donors showed that gene frequencies obtained for the two alleles of HPA-1 (P<0.001), HPA-2 (P = 0.001) and HPA-5 (P<0.001) were significantly different between the two groups of individuals. All natives tested carried the HPA-2a and the HPA-5a alleles, but the HPA-1b and HPA-4b alleles are absent from the Indian population. It was also observed that all blood donors carried the HPA-1a, HPA-4a and HPA-5a alleles. In conclusion, the present data indicate differences in the frequency of the HPA systems between Amazon Indians and Brazilian subjects who present a high rate of racial admixture. While the frequencies of the HPA-1 and HPA-5 genes seen in Amazon Indians are similar to those reported for Oriental populations, the frequencies of the HPAs alleles in Brazilian blood donors are comparable to those reported for populations in North America and Europe.

Microwave Spectrum, Structure, and Nuclear Quadrupole Coupling Constants of 1-Bromo-1-fluoroethane.

The microwave spectrum of 1-bromo-1-fluoroethane, CHBrF-CH(3) and CHBrF-CH(2)D ((79/81)Br), has been studied for the first time from 8 to 41 GHz. A least-squares analysis of the observed a- and b-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows: A = 8979.428(5) MHz, B = 2883.898(3) MHz, C = 2310.535(3) MHz, Delta(J) = 0.74(2) kHz, Delta(JK) = 2.49(3) kHz, Delta(K) = 5.3(5) kHz, delta(J) = 0.146(1) kHz, delta(K) = 2.75(4) kHz, chi(aa) = 493.49(29) MHz, chi(bb) - chi(cc) = -38.89(11) MHz, and ||chi(ab) || = 161.8(28) MHz for the CH(79)BrF-CH(3) species; A = 8979.257(5) MHz, B = 2859.072(3) MHz, C = 2294.572(3), Delta(J) = 0.76(2) kHz, Delta(JK) = 2.51(3) kHz, Delta(K) = 4.5(4) kHz, delta(J) = 0.145(1) kHz, delta(K) = 2.70(4) kHz, chi(aa) = 412.42(27) MHz, chi(bb) - chi(cc) = -32.56 (11) MHz, and ||chi(ab) || = 133.3(3) MHz for the CH(81)BrF-CH(3) species. The structural parameters are calculated from the 24 observed rotational constants, and electronic properties of the carbon-bromine bond in 1-bromo-1-fluoroethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. The molecular structure of 1-bromo-1-fluoroethane is found to be very close to that of 1,1-difluoroethane except for the C-Br bond. Copyright 1999 Academic Press.

Microwave power absorption in a multilayered cylindrical model of man near a flat reflector.

There are usually objects in the vicinity when a person is exposed to electromagnetic waves. It is exceedingly difficult to calculate the whole-body average specific absorption rate (SAR) in the microwave frequency region using a realistic heterogeneous model of man. In this paper, we use a multilayered cylinder model to numerically examine the average SAR of an adult standing near a flat reflector exposed to microwave energy. We also offer a comparison with existing data from a realistic model for an E-polarized wave below 600MHz.

Microwave Spectrum, Nuclear Quadrupole Coupling Constants, and Structure of Bromodifluoromethane

The microwave spectrum of bromodifluoromethane, CHBrF2 (Halon 1201) has been studied for the first time from 7 to 40 GHz. A least-squares analysis of the observed c-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows: A = 10199.7186(62) MHz, B = 2903.4150(26) MHz, C = 2360.1521(23) MHz, DeltaJ = 0.660(14) kHz, DeltaJK = 2.87(11) kHz, DeltaK = 8.95 kHz, deltaJ = 0.1344(24) kHz, deltaK = 3.22(15) kHz, chiaa = 521.281(92) MHz, chibb - chicc = -38.32(9) MHz, and |chiac| = 187.1(26) MHz for the 79Br species; A = 10199.5567(54) MHz, B = 2876.5588(20) MHz, C = 2342.3796(18) MHz, DeltaJ = 0.652(12) kHz, DeltaJK = 2.77(9) kHz, DeltaK = 8.21(61) kHz, deltaJ = 0.1300(19) kHz, deltaK = 2.97(13) kHz, chiaa = 435.61(10) MHz, chibb - chicc = -32.08(8) MHz, and |chiac| = 148.5(29) MHz for the 81Br species. The structural parameters are calculated from all these rotational constants and the electronic properties of the carbon-bromine bond in bromodifluoromethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. Copyright 1997 Academic Press. Copyright 1997Academic Press

Further study of microwave power absorption in a multilayered cylindrical model of man.

The paper describes microwave power absorption in a typical human being, modeled as a multilayered dielectric cylinder. Average specific absorption rate (SAR) was calculated for E- and H- polarized incident wave for different conditions of the object. Comparison with an existing method is treated, and correction of an erroneous result therein is reported.

Multibody effects on microwave power absorption by multilayered cylindrical models of man.

This paper presents an analysis of the interactions among multiple human bodies, modeled by multilayered cylinders, exposed to microwaves. Cylinders are used because it is very difficult to compute the whole-body average specific absorption rate (SAR) at higher frequencies using a realistic human model. The average SAR is numerically discussed for a typical case of the linear array of two and three adult body models when the wave is vertically incident to the array.

The synergistic purgative action of aloe-emodin anthrone and rhein anthrone in mice: synergism in large intestinal propulsion and water secretion.

This study aimed to explore the mechanism involved in the synergistic purgative action of aloe-emodin anthrone and rhein anthrone, the active metabolites of sennoside C. Aloe-emodin anthrone and rhein anthrone, and their equimolar mixture, induced excretion of an approximately equal number of faeces by intracaecal administration at a dose of 23.2 mumol kg-1 in mice (= 1.0 standard dose). The number of wet faeces induced by aloe-emodin anthrone was less than those of rhein anthrone and the mixture. At the same dose, rhein anthrone and the mixture significantly stimulated large intestinal propulsion, though aloe-emodin anthrone had little stimulatory effect. Aloe-emodin anthrone and rhein anthrone decreased net water absorption but could not reverse it to the net secretion at 1/2 dose. The mixture significantly decreased net water absorption and reversed it to the net secretion at this dose. These anthrones did not stimulate mucus secretion in the colon at 1/2 dose. We concluded that the synergistic purgative effect of aloe-emodin anthrone and rhein anthrone in mice results from synergistic stimulation of large intestinal transit and large intestinal water secretion.

Molecular cloning of human mitochondrial glycerophosphate dehydrogenase gene: genomic structure, chromosomal localization, and existence of a pseudogene.

cDNA of mitochondrial glycerophosphate dehydrogenase (mGPDH), a defect of which is a possible cause of non-insulin dependent diabetes mellitus, was cloned from a human insulinoma cDNA library. The deduced amino acid sequence showed 91% and 92% homology with those of rat and mouse mGPDH, respectively. The mGPDH gene was mapped to chromosome 2q23 by FISH analysis. Genomic clones for mGPDH were then isolated using mouse mGPDH cDNA and PCR products of human mGPDH cDNA as probes. Genomic structure was studied by sequencing the exon-intron boundaries and by PCR amplification of intronic regions using genomic clones as templates. The human mGPDH gene was shown to be composed of 15 coding exons, containing a (CA)n repeat region inside the gene, which was not polymorphic in the Japanese population. Genomic cloning also identified a pseudogene located on chromosome 19q13.4. These results provide information useful for analyzing the mGPDH gene in patients with non-insulin dependent diabetes mellitus.

Efficacy of combination antiplatelet therapy and nicardipine for chronic cerebral infarction.

To prevent recurrence of cerebral infarction (CI), the efficacy of antiplatelet therapy, when used in combination with a calcium antagonist, was examined. The study subjects were 57 chronic CI patients (40 men, 17 women; mean age, 68.5 years) who experienced either CI or its recurrence more than 3 months before the start of the study. They were randomly allocated into one of the following four groups for the 8-week study; group A--ticlopidine hydrochloride 200 mg once daily and nicardipine hydrochloride 20 mg three times daily (TID); group B--ticlopidine hydrochloride 200 mg once daily; group C--aspirin 81 mg once daily and nicardipine hydrochloride 20 mg TID; or group D--aspirin 81 mg once daily. Platelet aggregation was measured before treatment and 4 and 8 weeks after the initiation of each therapy by using adenosine diphosphate (ADP) (2 microM and 0.5 microM) and collagen (2 micrograms/mL), and evaluated in terms of percent maximum platelet aggregation. Results showed significant suppression of 2.0 microM ADP platelet aggregation in groups A, B, and C. At 0.5-microM ADP, only groups A and B showed significant platelet aggregation suppression. All groups showed significant suppression of collagen platelet aggregation. In comparing single therapy with combination therapy, groups A and B were not significantly different from one another after 4 or 8 weeks in 2-microM ADP or collagen platelet aggregation suppression. In contrast, group C had significantly greater suppression of both 2-microM ADP and collagen aggregations compared with group D. In conclusion, nicardipine hydrochloride administration with aspirin may be a useful alternative therapy for the prevention of CI recurrence.

Impression of smoothness of a sound stream in relation to legato in musical performance.

Physically continuous sounds do not always produce the subjective impression of legato. In the present study, the effect of temporal factors on the impression of smoothness of a sound stream was systematically investigated in relation to the dynamic characteristics of hearing. The results showed that decaying sounds, successively presented, were perceived as being marginally connected when the sounds physically overlapped, while steady-state sounds were perceived as being marginally connected when they were physically separated. It was also shown that judgments by the subjects agreed quite well with the effect intended by the pianist when the passage was given in different temporal interpretations.

Suppression of the purgative action of rhein anthrone, the active metabolite of sennosides A and B, by calcium channel blockers, calmodulin antagonists and indomethacin.

The involvement of Ca2+ in the mechanism of the purgative action of rhein anthrone was studied. Among individual or combination pretreatments with calcium channel blockers, calmodulin antagonists and prostaglandin biosynthesis inhibitors, the combination of indomethacin and nifedipine completely blocked the diarrhoea induced by rhein anthrone and also inhibited its effects on colonic fluid and electrolyte transport, and large intestinal motility. Calmodulin antagonists were less active regarding suppression of the effects of rhein anthrone. We concluded that, in addition to prostaglandins, diarrhoea induced by rhein anthrone must also involve the calcium channel which can be blocked by nifedipine, but not verapamil.

Metabolic activation of sennoside C in mice: synergistic action of anthrones.

Sennosides A and C directly injected into the caecum of mice showed equal purgative activity. Intracaecal administration reduced time to onset of diarrhoea induced by sennoside C from about 3 h after oral administration to about 24 min. At 2.3 h after oral administration of sennoside C, nearly equimolar amounts of aloe-emodin anthrone and rhein anthrone were detected in the large intestine of mice. The purgative effect of oral sennoside C could be reduced by pretreating mice with chloramphenicol. This was observed as a decreased formation of total anthrones in the large intestine. Both anthrones and an equimolar mixture of both anthrones directly injected into the caecum exerted a purgative effect, although the activity was lower for aloe-emodin anthrone. The intracaecal ED50 values were 54.5 (24.1-89.6), 11.4 (5.0-15.7) and 11.2 (6.1-14.6) mumol kg-1 for aloe-emodin anthrone, rhein anthrone and an equimolar mixture of both anthrones, respectively. We concluded that aloe-emodin anthrone and rhein anthrone, formed mainly by intraluminal bacterial action, are the true active metabolites of sennoside C in mice and that both anthrones synergistically exert their purgative effects on mice.

Suppression of the purgative action of rhein anthrone, the active metabolite of sennosides A and B, by indomethacin in rats.

Rhein anthrone (12.48 mg kg-1) produces watery and mucoid diarrhoea approximately 20 min after intracaecal administration to rats. Pretreatment with the prostaglandin (PG) biosynthesis inhibitor indomethacin (10 mg kg-1, i.p.) only delayed and did not completely block the onset of the induced diarrhoea. Rhein anthrone stimulated PGE2 release into the rat colonic lumen and the increased release was depressed by indomethacin. Rhein anthrone also accelerated large intestinal transit and this acceleration could be partly inhibited by indomethacin, which was probably responsible for the delay in the onset of diarrhoea. Indomethacin prevented the enhanced water, K+ and mucus secretion and the reduced Na+ absorption in the colon which were induced by rhein anthrone. The net water secretion could not be reversed to net absorption and the mucus secretion was only slightly depressed by indomethacin. Thus, our findings suggest that other mechanisms, together with the PG-dependent mechanism, are involved in the purgative action of rhein anthrone in rats.

Prostaglandin E2-mediated stimulation of mucus synthesis and secretion by rhein anthrone, the active metabolite of sennosides A and B, in the mouse colon.

Rhein anthrone, the active metabolite of sennosides A and B, stimulated PGE2 release into the mouse colonic lumen. At 6.24 mg kg-1, it decreased net water and Na+ absorption significantly in the case of water, but could not reverse the net absorption in mouse ligated colon, although it enhanced net K+ secretion. Pretreatment with indomethacin diminished the effects of rhein anthrone except on K+ net secretion. Rhein anthrone or PGE2 markedly stimulated mucus secretion and synthesis in mouse ligated colon. The enhanced mucus secretion and synthesis induced by rhein anthrone were significantly suppressed by pretreatment with indomethacin. Our results have shown that the colonic secretion of water and electrolytes mediated by PGE2 is partly involved in the rhein anthrone-induced diarrhoea but that in mice, the mucoid diarrhoea induced by rhein anthrone results mainly from PGE2-mediated mucus synthesis and secretion in the colon.

Involvement of prostaglandin E-like material in the purgative action of rhein anthrone, the intraluminal active metabolite of sennosides A and B in mice.

Intracaecal administration of rhein anthrone, the intraluminally active metabolite of sennosides A and B, to mice quickly induced severe diarrhoea. Pretreatment with the prostaglandin (PG) biosynthesis inhibitor, indomethacin, and PGE2 antagonist, SC-19220, prevented the onset of diarrhoea induced by rhein anthrone, but the PGE2 antagonist polyphoretin phosphate (PPP) showed only a weak inhibitory effect. Rhein anthrone stimulated the production of PGE-like material only in the colon and its large intestinal propulsive activity was depressed by indomethacin and SC-19220, but not by PPP which suggests that the release of PGE-like material has some role in its purgative action.