A study on the circadian rhythm of glucocorticoid receptor

Circadian rhythm in glucocorticoid receptor (GR) was studied in the rat liver and human peripheral leukocytes. For rats exposed to a natural environmental photic cycle or a 12L:12D artificial light regime, peak values of hepatic GR were detected between 23:00 and 02:00 h. Except for a 4-hour advancement of the peak, a similar circadian rhythm of hepatic GR was detected in rats reared under a reversed lighting regimen (12D:12L; lights on between 18:30 and 06:30 h). In human leukocytes, the peak value of GR was found to parallel that of plasma cortisol with high and low values detected at 04:00-08:00 h and 23:00-24:00 h, respectively. In patients suffering from Cushing's syndrome, the circadian rhythm of plasma cortisol either disappeared or was inverted while that of GR did not significantly deviate from the normal subjects. For apoplexic patients with lesions localized to the base of the brain as indicated by computerized tomography, the diurnal variation of GR was abolished. Conversely, diurnal rhythmicity persisted in apoplexy patients whose lesions were in the cerebral cortex. Thus, we postulated that the circadian modification of GR was independent of the diurnal fluctuations in plasma cortisol level or the circadian variations in environmental lighting and that the rhythmicity might be regulated by the 'circadian pacemaker' located in the human basal brain. These diurnal variations in GR might serve to coordinate the reactivity of the target cells to cortisol because the diurnal rhythms of a GR-mediated response, the fractional inhibition of chemotactic migration rate of polymorphonuclear leukocytes by cortisol, were found to be synchronous with those of GR.

Activation of idiotype-specific CD4+ T-cell line: cellular processing of exogenous self-immunoglobulin

An idiotype (Id)-specific long-term cultured T-cell line has been generated from BALB/c mice immunized with M315 (alpha, lambda 2). The cell line comprises both CD3+ and CD4+ but CD8- cells. The T-cell line is stimulated in a class II major histocompatibility complex (MHC)-restricted manner, and is capable of producing interleukin-2 (IL-2) in response to the Id along with Iad-bearing antigen-presenting cells (APC). Fine Id specificity analysis has shown that changes in amino acid residues, Phe-94, Arg-95 and Asn-96, located on the VL-315, resulting from a somatic mutation mechanism of the mouse V lambda 2 gene, contribute to the T-cell activation. Pretreatment of APC with either glutaraldehyde or paraformaldehyde prevented both Fv-315 and VL-315 from triggering the T cells. This suggested that further processing of VL is required for T-cell activation. To clarify this point, we have generated a synthetic peptide, designated P18, which spans residues 91-108 of VL-315. In sharp contrast to VL, prefixed APC were capable of presenting P18 to stimulate the T-cell line to induce IL-2.

Receiving efficiency of monostatic pulsed coherent lidars. 1: Theory

The receiving efficiency eta as a function of range z is investigated for pulsed coherent lidars using a theory that relates eta(z) to the transmitted laser intensity and the point-source receiving efficiency eta(s)(r,z). The latter can be calculated either by a forward method, or by a backward method that employs the back-propagated local oscillator (BPLO) approach. The BPLO method is efficient and accurate provided that cascaded diffraction effects inside the lidar system are properly taken into account. The theory is applied to the ideal case to examine the optimization of the system when both transmitted and BPLO fields at the antenna are Gaussian, including optimum telescope aperture.

Receiving efficiency of monostatic pulsed coherent lidars. 2: Applications

Using the theory developed in Part 1, the receiving efficiency as a function of range, eta(z), is calculated under different conditions for the NOAA/ERL/Wave Propagation Laboratory CO(2) Doppler lidar. Theoretical analyses, numerical calculations, and experimental measurements are carried out to quantify the sensitivity of eta(z) to transmitted laser beam quality, telescope focal setting, telescope power, scanner astigmatism, LO beam divergence, and system misalignment. These results bring insight to the design of practical coherent lidar systems.

Molecular characterization of the t(10;14) translocation breakpoints in T-cell acute lymphoblastic leukemia: further evidence for illegitimate physiological recombination

The t(10;14)(q24;q11) translocation is a non-random chromosome change seen in the leukemic cells of 5-10% of patients with T-cell acute lymphoblastic leukemia (T-ALL). Recent studies support the hypothesis that the translocation occurs in the course of aberrant physiological recombination and results in the juxtaposition of a T-cell receptor (TCR) gene in 14q11 with a putative oncogene, TCL3, in 10q24. We cloned and sequenced the translocation breakpoints on both derivative 10q+ and 14q- chromosomes from a patient with t(10;14)(q24;q11) T-ALL. Two distinct diversity segments of TCRD, D delta 2 and D delta 3, were identified at the two translocation breakpoints on chromosome 14. The 9.5 kb DNA that separates these two subunits in the germline was deleted, possibly in the course of a D-D joining event. The two chromosome 10 breakpoints were 10 nucleotides apart and occurred in the immediate vicinity of a pseudo-heptamer signal motif. N-region addition is also evident at the breakpoint on the derivative chromosome 10. Our observations strongly suggest that the IG/TCR recombinase normally involved in V-(D)-J joining was involved in the process of the t(10;14)(q24;q11) translocation.

Cytokine production in lethal and non-lethal murine malaria

Levels of IFN-gamma, IL-2 and IL-4 were measured in vitro during the course of non-lethal Plasmodium chabaudi adami and lethal P. chabaudi strain 1309 infections in BALB/cByJ mice. Spleen cells from mice infected with the non-lethal Plasmodium had a higher initial response to P. chabaudi antigens than mice infected with P. chabaudi strain 1309, as determined by measuring all three lymphokines. We conclude that both Th1 and Th2 subsets of T helper lymphocytes are activated during P. chabaudi adami infection but that these responses are suppressed in mice infected with the more virulent P. chabaudi strain 1309.

A study of hepatitis B virus DNA in situ hybridization for chronic active hepatitis

Liver biopsies of 50 patients with chronic active hepatitis B were analysed immunohistochemically for HBcAg and HBsAg, and, by in situ hybridization, for hepatitis B virus (HBV) DNA. Double staining for manifesting HBV DNA and viral antigen simultaneously was also performed in some of them. The localization patterns of HBV DNA in hepatocytes could be classified into whole cytoplasmic, submembranous, nucleic and intermembranous types. The last type suggests that HBV DNA might be transmitted directly to the adjacent hepatocytes through the cell membranes. The double staining indicated that the majority of hepatocytes with high levels of HBV replication did not contain HBcAg of HBsAg. Conversely, most liver cells with strongly positive HBAg had low or negligible levels of viral replication. In addition, in a few cases HBV DNA could be found in the cytoplasm of bile ductule epithelia and sinusoidal endothelia.

[An epidemiological survey of gallstones with gray-scale ultrasound]

Gray-scale real-time ultrasound has been employed to investigate gallstone with a positive result of 553 cases out of 15,856 healthy subjects in city and countryside, the incidence being 34.88%. The feature of incidence is as follows: 1. The incidence of the simple gallbladder stone is more common than that of the other sites (male is about 81.15%, female is about 87.29%); 2. The incidence of gallstones of city residents is higher than that of the country people with significant difference statistically (P less than 0.01); 3. The incidence of gallstone in female city residents is higher than male, about 2.5:1, which shows significant difference. (P less than 0.01); 4. The incidence of gallstones in female city residents is higher than in countryside (P less than 0.01); 5. There is no significant difference in the incidence of gallstone between male and female in the countryside (P greater than 0.05); 6. There is no significant difference in the incidence of gallstones between city male and the male in the countryside (P greater than 0.05); 7. Either in the city or in the countryside, it has been shown that there is a tendency of increasing incidence of gallstone with age in both sexes (P less than 0.01). The relationship between the gallstone and the clinical symptoms has been discussed in this paper.

Human immune response directed against Plasmodium falciparum heat shock-related proteins

Heat shock-related stress proteins present in all eucaryotes and procaryotes have been shown to be immune targets in a broad range of infections. We have analyzed sera from people exposed primarily to Plasmodium falciparum for specific antibodies against two heat shock-related proteins (proteins similar to the heat shock protein with a molecular weight of 75,000 [Pfhsp] and a glucose-regulated protein with a molecular weight of 72,000 [Pfgrp]). In an immunoprecipitation analysis with metabolically labeled parasites and synthetic peptides in an enzyme-linked immunosorbent assay, specific antibodies against Pfhsp and Pfgrp were detected in the sera of these individuals. Sera from people exposed to a different human malarial parasite, Plasmodium vivax, did not react with the peptides in an enzyme-linked immunosorbent assay. Southern blot analysis with DNA isolated from P. falciparum from different geographical locations showed a conservation of genes for these stress proteins; thus, they are likely to be immune targets in various endemic areas. Lymphocytes from two tested immune donors responded in proliferation assays to purified Pfhsp and Pfgrp and purified recombinant proteins. However, a similar response was also seen in lymphocytes from nonimmune individuals and has raised questions pertaining to a generalized responsiveness of lymphocytes to some common determinants present in heat shock-related proteins in various pathogens.

[Effect of dry ginger and roasted ginger on experimental gastric ulcers in rats]

This paper reports the effect of dry ginger and roasted ginger decoctions on four experimental gastric ulcer models in rats at an oral administration of 4.5 g/kg. The result shows that the roasted ginger has an obvious inhibiting tendency on three gastric ulcer models except the indomethacin induced model while the dry ginger has no such effects. The acute toxicity test has shown that the LD50 of roasted ginger decoction administered orally is 170.6 +/- 1.1 g/kg, but it is over 250 g/kg with dry ginger. This suggests that the water soluble constituents of the dry ginger have changed in the roasting process.

[In situ hybridization study of HBV DNA in chronic active hepatitis]

Liver biopsies from 50 patients with chronic active hepatitis B were analysed immunohistochemically for HBcAg and HBsAg, and with in situ hybridization for HBV DNA. Double labelling technique for detecting HBV DNA and viral antigens simultaneously was also performed in some of these cases. The results showed that localization of HBV DNA in hepatocytes could be classified into whole cytoplasmic, submembranous, nucleic and intermembranous types. The last type suggests that HBV DNA might be transmitted directly to the adjacent hepatocytes through the cell membrane. By double labelling technique, it was disclosed that most hepatocytes with high level of HBV replication did not contain HBcAg or HBsAg. Conversely and most liver cells strongly positive for HBAg have low or negligible level of viral replication. Additionally, in a few cases, HBV DNA was found in the cytoplasm of bile ductule epithelia and sinusoidal endothelia.

[Differential diagnosis of parotid gland masses by gray scale real-time ultrasound]

This paper reports the ultrasonographic diagnoses in 18 cases of parotid gland masses confirmed by surgery and biopsy and pathology. The diagnostic accuracy was 100% (18/18) in the judgement in locations and was 72% (13/18) in the judgement in the nature of the disease. The clinical value of ultrasonographic diagnosis in parotid gland masses and the features of the sonographic images in benign and malignant tumors were analysed and discussed.

Premature translation termination of the pre-E1 alpha subunit of the branched chain alpha-ketoacid dehydrogenase as a cause of maple syrup urine disease in Polled Hereford calves

Maple syrup urine disease in man and cattle is an inborn metabolic error caused by the deficiency of the branched chain alpha-ketoacid dehydrogenase. We have studied the molecular basis of the disease in Polled Hereford calves. The E1 component of branched chain alpha-ketoacid dehydrogenase was virtually undetectable by Western blot analysis of fibroblasts from an affected calf. Northern blot analysis failed to detect the E1 alpha mRNA species in the fibroblasts. Nevertheless, it was readily demonstrated by reverse transcription of RNA followed by polymerase chain reaction that the mRNA for the E1 alpha subunit was present in the cells, albeit at very low concentrations. Sequencing of the polymerase chain reaction-generated cDNA for the entire coding region of the E1 alpha subunit revealed a single base substitution at codon -6 (CAG to TAG). This mutation introduces a stop codon in the leader peptide of the E1 alpha subunit, resulting in the premature termination of translation. The mutation was verified by hybridization of the amplified cDNA fragments from two affected calves with allele-specific oligonucleotides. This finding explains the pathogenesis of maple syrup urine disease in this breed of cattle, which provides the only known animal model for the human disease. In addition, the results provide evidence for the effect of premature translation termination on reducing the steady-state mRNA level and the dependence of E1 beta protein stability on the co-expression of the E1 alpha.

Regulation of the branched-chain alpha-ketoacid dehydrogenase and elucidation of a molecular basis for maple syrup urine disease

The hepatic branched-chain alpha-ketoacid dehydrogenase complex plays an important role in regulating branched-chain amino acid levels. These compounds are essential for protein synthesis but toxic if present in excess. When dietary protein is deficient, the hepatic enzyme is converted to the inactive, phosphorylated state to conserve branched-chain amino acids for protein synthesis. When dietary protein is excessive, the enzyme is in the active, dephosphorylated state to commit the excess branched-chain amino acids to degradation. Inhibition of protein synthesis by cycloheximide, even when the animal is starving for dietary protein, results in activation of the hepatic branched-chain alpha-ketoacid dehydrogenase complex to prevent accumulation of branched-chain amino acids. Likewise, the increase in branched-chain amino acids caused by body wasting during starvation and uncontrolled diabetes is blunted by activation of the hepatic branched-chain alpha-ketoacid dehydrogenase complex. The activity state of the complex is regulated in the short term by the concentration of branched-chain alpha-ketoacids (inhibitors of branched-chain alpha-ketoacid dehydrogenase kinase) and in the long term by alteration in total branched-chain alpha-ketoacid dehydrogenase kinase activity. cDNAs have been cloned and the primary structure of the mature proteins deduced for the E1 alpha subunit of the human and rat liver branched-chain alpha-ketoacid dehydrogenase complex. The cDNA and protein sequences are highly conserved for the two species. Considerable sequence similarity is also apparent between the E1 alpha subunits of the human branched-chain alpha-ketoacid dehydrogenase complex and the pyruvate dehydrogenase complex. Maple syrup urine disease is caused by an inherited deficiency in the branched-chain alpha-ketoacid dehydrogenase complex. The molecular basis of one maple syrup urine disease family has been determined for the first time. The patient was found to be a compound heterozygote, inheriting an allele encoding an abnormal E1 alpha from the father, and an allele which is not expressed from the mother. The only known animal model for the disease (Polled Hereford cattle) has also been characterized. The mutation in these animals introduces a stop codon in the leader peptide of the E1 alpha subunit, resulting in premature termination of translation. Two thiamine responsive patients have been studied. The deduced amino acid sequences of the mature E1 alpha subunit and its leader sequence were normal, suggesting that the defect in these patients must exist in some other subunit of the complex. 3-Hydroxyisobutyrate dehydrogenase and methylmalonate-semialdehyde dehydrogenase, two enzymes of the valine catabolic pathway, were purified from liver tissue and characterized.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of a rice glutelin promoter in transgenic tobacco

A chimeric gene consisting of the 5' flanking sequences of a rice glutelin gene (Gt3) linked to the chloramphenicol acetyltransferase (CAT) coding segment was introduced into tobacco via Agrobacterium tumefaciens-mediated transformation. CAT enzyme activity could be detected in extracts from seeds as early as 8 days after flowering and obtained a maximum level at 16 days after flowering, the onset of overall protein accumulation. Significant expression of CAT activity in non-seed tissues occurred in some, but not all plants, suggesting possible chromosome position effects on non-seed tissue expression. A positive correlation was observed between expression levels in seeds and gene copy numbers.

All-optical power-controlled switching in four-wave mixing

The use of four-wave mixing as an all-optical switching device is described. The switching process involves strong pump depletion and results from large-signal interactions. Interesting relationships among the input, the optical control, and the output signals and the parameters of the nonlinear medium are identified.

[Changes in peripheral leukocytic glucocorticoid receptor in patients with ischemic and hemorrhagic stroke]

The maximal binding capacity (Ro) and dissociation constant (Kd) of glucocorticoid receptor (GCR) in peripheral leukocytes were estimated by radioligand binding method and the plasma cortisol levels measured in 25 stroke patients (hemorrhagic 15, ischemic 10), compared with 12 healthy controls, the plasma cortisol level in stroke patients were significantly higher. The plasma cortisol level of 15 hemorrhagic and 10 ischemic stroke patients and 12 controls determined by RIA were 1.12 +/- 0.21, 0.90 +/- 0.28 and 0.45 +/- 0.09 nmol/L respectively. Ro of leukocytic GCR in hemorrhagic stroke were significantly lower than that of ischemic stroke and controls. No difference was found between ischemic stroke and controls. No difference was found between ischemic stroke and controls. Ro of GCR in 15 hemorrhagic stroke, 10 ischemic stroke patients and 12 controls were 3496 +/- 424, 5678 +/- 1101 and 5940 +/- 763 sites/cell respectively kd of GCR were 10.47 +/- 4.17, 7.01 +/- 3.24 and 5.81 +/- 1.05 nmol/L respectively. Affinity of GCR in 15 hemorrhagic stroke patients was significantly lower. In conclusion, lower number and affinity of leukocytic GCR and higher plasma cortisol level were demonstrated in hemorrhagic stroke patients, but normal number and affinity of GCR and higher plasma cortisol level in ischemic stroke patients.

Calcium antagonists in prevention of hypertension and stroke in stroke-prone spontaneously hypertensive rats

To investigate the effect of Calcium antagonists (Ca-An) with different tissue specificity in the development of hypertension and stroke in salt-loading SHRSP, three experiments were conducted. In experiment I (1), 50 8-week-old male SHRSP were divided into three groups and given nifedipine (NF, 32 mg/kg/day), menidipine (MN 32 mg/kg/day) and placebo (control group) respectively. In the control group 83.3% (15/18) died of stroke and 17 showed renal vascular sclerosis. Their average lifespan was 84 days. NF and MN significantly reduced systolic blood pressure (SBP), and no stroke of renal vascular sclerosis developed. In experiment I (2), 54 7-week-old male SHRSP were divided into three groups (18 in each group). They were treated with nimodipine (NM) 20 mg/kg/day, 2 mg/kg/day and placebo respectively. NM (20 mg/kg/day) markedly lowered SBP and postponed the onset of stroke. Only 11% died in 17 weeks. NM (2 mg/kg/day did not lower SBP but postpond the onset of stroke. In experiment II (1), 29 10-week-old female SHRSP were divided into three groups: Group A was given NF 32 mg/kg/day, group B was parathyroidectomized (PTX) and group C served as control. PTX group did not lower SBP but could postpone the onset of stroke. In experiment II (2), 33 male SHRSP were divided into three groups and ticated as described above in experiment II (1) (11 in each group). Seven weeks after the experiment, the brain blood flow of NF group was significantly greater (67.5%) than that of the control and PTX groups. In experiment III, 27 7-week-old male SHRSP were divided into three groups as described above in experiment I (2).(ABSTRACT TRUNCATED AT 250 WORDS)

Autoradiographic localization of endothelin-1 binding sites in the cardiovascular and respiratory systems

Specific high-affinity binding sites for endothelin-1 (ET-1) have been demonstrated in peripheral tissues using the technique of in vitro receptor autoradiography. Binding was time dependent and saturable and inhibited by coincubation with an excess of unlabeled ET-1 but resistant to dissociation. Binding sites were localized to blood vessels of all sizes including coronary arteries, intrapulmonary vessels, and intrarenal and intrasplenic arteries. In addition, high-affinity binding sites were identified on airway smooth muscle, over alveolar septa, and on nerve trunks. Scatchard analysis of the data revealed a Bmax of 250 amol/mm2 and a Kd of 0.1 nM for the binding of rat tracheal smooth muscle, with similar values for porcine coronary artery. The localization of binding sites is consistent with the known effects of ET-1 and suggests a direct action on specific receptors.

Changes in erythrocyte membranes in burned rabbits

Eighteen white rabbits were subjected to a 30 per cent TBSA full thickness burn. Wound infection was found 9-13 days after injury and became severe a week or so later. ATPase activities, antioxidation ability, the proteins of erythrocyte membranes, and the Na+ contents of erythrocytes and serum were determined. The Ca++-ATPase activity was elevated during the first 17 days postburn, but showed a decline at the time of severe wound infection; the Na+,K+-ATPase activity showed peaks on postburn days 2 and 6, and then fluctuated above the preburn level. The change in Mg++-ATPase activity was similar to Na+,K+-ATPase. The erythrocyte Na+ content was increased, and the level of serum Na+ was decreased up to postburn day 6. Subsequently the erythrocyte Na+ was reduced and the serum Na+ increased up to day 17 postburn. The percentage of erythrocyte haemolysis in H2O2 was increased after the burn and became markedly so during wound infection, indicating that the antioxidation ability of burned rabbit erythrocytes was markedly impaired. During the period of wound infection, Coomassie blue-stained protein bands in SDS-polyacrylamide gel showed some changes in size and proportion in burned rabbits. For example, the second band was wider, the band 2 to band 1 ratio increased, and band 5 was smaller than before injury. These results seem to show that burn injury, especially when associated with sepsis, may affect both the structure and function of biological membranes.

Correction function for the lidar equation and some techniques for incoherent CO(2) lidar data reduction

The convolution effect in CO(2) lidar return signals caused by the long laser pulse is analyzed by modifying the original lidar equation and introducing a correction function C(r)(R). The characteristics of C(r)(R) are discussed in detail, leading to a deconvolution technique consisting of a two-step iteration procedure for the extraction of both the ackscattering coefficient and the gas species content in differential absorption lidar measurement.

Technique for correcting effects of long CO(2) laser pulses in aerosol-backscattered coherent lidar returns

The convolution effect in aerosol backscattered CO(2) coherent lidar returns caused by the long tail of the laser pulse is analyzed by modifying the original lidar equation and introducing a correction function C(r)(R). The characteristics of the correction function and its effect on differential absorption lidar water vapor measurements are investigated for coherent lidars. A deconvolution technique is developed consisting of a leastsquares fitting and iteration procedure for retrieval of the mean value of the atmospheric backscattering coefficient beta and a reverse filtering procedure for estimating the fluctuation components of the beta profile. Data obtained with the WPL coherent CO(2) lidar are reanalyzed using the above method, giving improved estimates of the structures and the mean water vapor content.

Describing interactions in dystocia scores with a threshold model

Field data on calving difficulty scores provided by the American Simmental Association were subjected to two methods of analysis: ordinary least-squares analysis and maximum likelihood with an assumed threshold model. In each analysis, the model included the interaction of sex of calf X age of dam. This interaction was readily apparent in the data (observed scale): within the youngest dams 58% of the heifer calves and 37% of the bull calves were born unassisted vs 96% and 92%, respectively, in the oldest dams. The objective was to determine if this interaction would be greatly reduced or would disappear on the underlying scale of a threshold model. The least-squares estimate of the sex difference was greatest within the youngest age-of-dam group (18 to 24 mo) and steadily declined with increasing age of dam, approaching zero for dams 6 yr and older. In contrast, the estimates of the sex difference from the threshold analysis were remarkably similar across ages of dam. It was concluded that observed interactions in calving ease data could be adequately described by a threshold model in which the effects of age of dam and sex of calf act additively on the underlying variable.

[Detection of cytomegalovirus (CMV) DNA sequence in biopsy samples of cervical cancer]

Biopsy samples of the cervical cancer and cervicitis were analysed by HCMV-DNA hybridization method. The results indicated that HCMV-DNA was detected in 21 (36%) of 59 cervical cancer and 6 (21%) of 28 cervicitis specimens, using 32P-DNA probe containing transformation gene (14% of total genome) to hybridize. None of 25 cervical cancer and 19 cervicitis samples showed positive HCMV-DNA, using 32P-DNA probe without transformation gene (76% of total genome). The preliminary results show that the sequence of CMV transformation gene is present in about one third of cervical cancer and one fifth of cervicitis biopsy samples tested. This detection rate is lower than that of Taiwan Province and Africa, and slightly higher than that of the USA and Finland. The relation between the HCMV and cervical cancer is being further studied.

Cytoskeletal perturbation induced by herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)

To understand the mechanisms of toxicity of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), we have studied their effects on the cytoskeletal organization, particularly microtubules (MT) and microfilaments (MF), DNA synthesis, and the synthesis and composition of cytoskeletal proteins in mouse 3T3 cells. Exposure of cells to 2,4-D or 2,4,5-T resulted in a dose-dependent inhibition of DNA synthesis; 50% inhibition occurred at 2.21 mM and 0.90 mM for 2,4-D and 2,4,5-T, respectively. Furthermore, a strong synergistic inhibition of DNA synthesis was produced by mixtures (each having a total concentration of 1.25 mM) of 2,4-D with 2,4,5-T. Similarly, 2,4,5-T is more potent than 2,4-D in causing cytoskeletal perturbation as revealed by fluorescence microscopy. Treatment of cells with 2,4-D (2.5 mM) or 2,4,5-T (1.25 mM) for 20 h resulted in severe MT aggregation and the appearance of large bundles, which were organized in a rope-like structure in the former and a dramatic octopus-like pattern in the latter. Further, MT bundling is particularly severe in the cell center. Under these conditions, marked changes in MF organization also occurred as evidenced by clustering and crisscrossing of MF in the perinuclear region. A 1:1 mixture (final = 1.25 mM) of 2,4-D and 2,4,5-T, a formulation equivalent to Agent Orange composition, also induced a dramatic perturbation to the organization of MT and MF, resulting in the formation of ring-like structures. MT bundling is still apparent, especially around the outer edge of the "rings." MF are localized predominantly along the cell periphery, where they appear to be aggregated tightly forming patches. Surprisingly, the synthesis and composition of cytoskeletal proteins, which are resistant to detergent extraction but released by CaCl2, are essentially unaffected by 2,4-D or 2,4,5-T. These results suggest that the dramatic perturbation of the cytoskeletal morphology caused by these herbicides probably only results from a structural reorganization and redistribution of MT and MF.

Isolation and Characterization of a Fast-Growing, Thermophilic Methanobacterium Species

A thermophilic, autotrophic methanogen (strain CB12, DSM 3664) was isolated from a mesophilic biogas digestor. This bacterium used H 2 -CO 2 or formate as a substrate and grew as short rods, sometimes in pairs and in crooked filaments. Motility was not observed. Its optimum temperature (56°C) was lower than that of other thermophilic members of the genus Methanobacterium . The maximum observed specific growth rate was 0.564 h −1 (74-min doubling time).

Studies on systemic pharmacological effects of artesunate

These studies report that artesunate at lower dosage levels (100 mg kg-1 i.v. or i.p.) in animals (the dosage of artesunate in human clinical use as an antimalarial is 2 mg kg-1 i.v.) had no significant systemic pharmacological effects, i.e. artesunate had a relatively high selectivity as an antimalarial. However, at higher dosage levels there was an appearance of sedative effects, lowered movement of synchronism, elevation of tolerated lack of oxygen, lowered body temperature, analgesia, muscle relaxation, tremor, convulsions, depressed respiration and heart beat, lowered blood pressure, and depressed activity of the gastrointestinal tract.