Beneficial effect of Rhodopseudomonas palustris on in vitro rumen digestion and fermentation

As a member of photosynthetic bacteria, Rhodopseudomonas palustris, which has extraordinary metabolic versatility, has been applied as one of potential probiotics in feed industry. To explore whether R. palustris can increase rumen microbial viability and thus improve microbial fermentation, a 2×5 factorial experiment was conducted to evaluate the effect of R. palustris at dose rates of 0, 1.3, 2.6, 3.9, 5.2×10⁶ cfu/ml on ruminal fermentation of two representative total mixed rations (HY, a ration for high-yield (>32 kg/d) lactating cows; LY, a ration for low-yield (<25 kg/d) lactating cows). After a 48 h in vitro rumen incubation, both rations resulted in different fermentation characteristics. The HY in comparison with LY group presented greater in vitro dry matter disappearance (IVDMD), cumulative gas production (GP₄₈) and total volatile fatty acids (VFA, P<0.01). Increasing R. palustris addition linearly increased IVDMD (P<0.01) and GP₄₈ (P<0.05), and the IVDMD increment in response to R. palustris addition was greater in LY than HY group (6.4% vs 1.4%). Meanwhile, increasing R. palustris addition also linearly enhanced microbial protein synthesis and increased total VFA production (P<0.01), especially in LY group (up to 21.5% and 24.5% respectively). Unchanged acetate and declined propionate in molar percentage were observed in response to the R. palustris addition. Furthermore, increasing R. palustris addition altered fermentation gas composition in which molar O₂ proportion in headspace of fermentation system was linearly reduced by 46.1% in LY and 32.9% in HY group, respectively (P<0.01), and methane production in both ration groups was enhanced by 1.9-4.1% (P=0.02). In summary, the R. palustris addition exhibited high potential for promoting the growth of rumen microorganism and enhancing microbial fermentation towards non-glucogenic energy supply by maintaining an anaerobic environment to microbe equilibrium.

[Clinical experiences of laparoscopic radical cystectomy and urinary diversion in the elderly patients with bladder cancer]

Objective: To optimize the surgical procedures of laparoscopic radical cystectomy and urinary diversion for the elderly patients with bladder cancer, generalize operating technique, summarize clinical experiences. Methods: From July 2004 to October 2016, laparoscopic radical cystectomy (LRC) and urinary diversion was performed in 68 elderly patients (≥75 years old) diagnosed with bladder cancer in urology department of Beijing Chaoyang Hospital, Capital Medical University, and the relevant clinical and follow-up data were retrospectively reviewed. All the patients were pathologically diagnosed and their perioperative data, postoperative pathological results, postoperative complications and follow-up outcomes were recorded and analyzed. Results: Among 68 elderly patients with bladder cancer, fifty patients were male and 18 were female, the age of whom were (79±4) (range 75 to 91) years old. The Charlson comorbidity index (CCI) score was 6±1 (range 5 to 7). All the 68 operations were successfully performed without conversion to open surgery. There were 26 cases receiving cutaneous ureterostomy, 34 cases receiving ileal conduit (intracorporeal for 16 cases and extracorporeal for 18 cases) and 8 cases receiving orthotopic ileal neobladder (intracorporeal for 4 cases and extracorporeal for 4 cases; Xing's technique for 4 cases, T-Pouch for 2 cases and Studer-Pouch for 2 cases) respectively, and the operation time of these three groups were (221±47) min, (315±70) min and (358±90) min respectively, the estimated blood loss were 100 (87, 200)ml, 300 (250, 500) ml and 250 (113, 725) ml respectively, the time of intake of liquid diet were 3 (2, 4) d, 6 (5, 7) d and 9 (5, 12) d respectively, and the postoperative hospital stay were (12±6) d, (24±11) d, and (27±11) d respectively. Postoperative pathological results showed urothelial carcinoma in 64 patients, squamous cell carcinoma in 2 patients and adenocarcinoma in 2 patients. Sixty patients received laparoscopic pelvic lymphadenectomy and the number of dissected lymph nodes was 17.1±7.0. There were 46 cases with T stage greater than or equal to T2 (46/68, 67.6%), 4 cases of low grade (4/68, 5.9%) and 60 cases of high grade (60/68, 88.2%). All the early postoperative (within 30 days after the operation) complications were grade Ⅰ-Ⅱ mainly manifested as fever, pain and infection that could get better with symptomatic treatment, and the incidence rate were 30.8% for cutaneous ureterostomy, 29.4% for ileal conduit and 37.5% for orthotopic ileal neobladder. The patients were followed up for a median period of 93.5 months without obvious hydronephrosis and impaired renal function. The 5-year cancer specific survival rate and overall survival rate were 57% and 50% respectively. There was significant difference between the preoperative and postoperative QOL (quality of life) score (56.0±10.0 and 47.4±5.8 respectively, P<0.05) which indicated that the patients' postoperative quality of life was greatly improved. Conclusions: Laparoscopic radical cystectomy and urinary diversion for the elderly patients with bladder cancer is safe and feasible, and owns great therapeutic value.

Arginase Inhibition Suppresses Native Low-Density Lipoprotein-Stimulated Vascular Smooth Muscle Cell Proliferation by NADPH Oxidase Inactivation

PURPOSE

Vascular smooth muscle cell (VSMC) proliferation induced by native low-density lipoprotein (nLDL) stimulation is dependent on superoxide production from activated NADPH oxidase. The present study aimed to investigate whether the novel arginase inhibitor limonin could suppress nLDL-induced VSMC proliferation and to examine related mechanisms.

MATERIALS AND METHODS

Isolated VSMCs from rat aortas were treated with nLDL, and cell proliferation was measured by WST-1 and BrdU assays. NADPH oxidase activation was evaluated by lucigenin-induced chemiluminescence, and phosphorylation of protein kinase C (PKC) βII and extracellular signal-regulated kinase (ERK) 1/2 was determined by western blot analysis. Mitochondrial reactive oxygen species (ROS) generation was assessed using MitoSOX-red, and intracellular L-arginine concentrations were determined by high-performance liquid chromatography (HPLC) in the presence or absence of limonin.

RESULTS

Limonin inhibited arginase I and II activity in the uncompetitive mode, and prevented nLDL-induced VSMC proliferation in a p21Waf1/Cip1-dependent manner without affecting arginase protein levels. Limonin blocked PKCβII phosphorylation, but not ERK1/2 phosphorylation, and translocation of p47phox to the membrane was decreased, as was superoxide production in nLDL-stimulated VSMCs. Moreover, mitochondrial ROS generation was increased by nLDL stimulation and blocked by preincubation with limonin. Mitochondrial ROS production was responsible for the phosphorylation of PKCβII. HPLC analysis showed that arginase inhibition with limonin increases intracellular L-arginine concentrations, but decreases polyamine concentrations. L-Arginine treatment prevented PKCβII phosphorylation without affecting ERK1/2 phosphorylation.

CONCLUSION

Increased L-arginine levels following limonin-dependent arginase inhibition prohibited NADPH oxidase activation in a PKCβII-dependent manner, and blocked nLDL-stimulated VSMC proliferation.

Growth under elevated air temperature alters secondary metabolites in Robinia pseudoacacia L. seedlings in Cd- and Pb-contaminated soils

Plant secondary metabolites play a pivotal role in growth regulation, antioxidant activity, pigment development, and other processes. As the global climate changes, increasing atmospheric temperatures and contamination of soil by heavy metals co-occur in natural ecosystems, which alters the pH of rhizosphere soil and influences the bioavailability and mobility of metals. Elevated temperatures in combination with heavy metals are expected to affect plant secondary metabolites, but this issue has not been extensively examined. Here, we investigated secondary metabolites in Robiniapseudoacacia seedlings exposed to elevated temperatures using a passive warming device in combination with Cd- and Pb-contaminated soils. Heavy metals significantly stimulated the accumulation of saponins, phenolic compounds, and flavonoids in leaves and stems; alkaloid compounds increased in leaves and decreased in stems, and condensed tannins fluctuated. Elevated temperatures, alone and in combination with Cd and Pb, caused increases in secondary metabolites in the plant tissues. Phenolic compounds showed the greatest changes among the secondary metabolites and significant interactive effects of temperature and metals were observed. These results suggest that slightly elevated temperature could enhance protective and defense mechanisms of Robinia pseudoacacia seedlings exposed to heavy metals by stimulating the production of secondary metabolites.

Raising Harmonic Variation of Arterial Pulse in Dying Rats

Our previous study revealed that the coefficient of variation of harmonic magnitude (HCV) of radial arterial pulse was significantly raised before the death of cancer patients. In this study, we recorded the caudate arterial pulse of 24 Sprague-Dawley rats that had a fatal dose of urethane injected into their abdomens. Twenty rats were dead within 3 hours after the injection and four survived. We defined the last 100 minutes of each rat's life as the dying process. During the dying process, we found that both the systolic blood pressure and diastolic blood pressure dropped steeply during the last 5 minutes. However, all HCVs, except HCV1, climbed steeply before the last 5 minutes. The HCV1 of the dying rats was significantly higher than that of rats that survived, starting from the first minute (P<0.01). The HCV2 of the dying rats was significantly higher than that of the survived rats starting from the 52nd minute (P<0.05). The HCV3 and HCV4 of the dying rats were significantly higher than those of the survived rats until the 70th minute and the 80th minute, respectively (P<0.05). Furthermore, HCV2–HCV4 proceeded with the dying process and increased gradually. We concluded that HCVs, which failed first in the high-frequency components and then in the low-frequency components, could provide physicians with earlier information to prevent the coming failure of circulatory system, and could reflect quantitatively pathological severity and predict patient outcome. The specific Fourier components in the pulse provide more physiological information than systolic and diastolic blood pressures.

Evaluating microcirculation by pulsatile laser Doppler signal

Laser Doppler flowmetry (LDF) is a popular method for monitoring the microcirculation, but it does not provide absolute measurements. Instead, the mean flux response or energy distribution in the frequency domain is generally compared before and after stimulus. Using the heartbeat as a trigger, we investigated whether the relation between pressure and flux can be used to discriminate different microcirculatory conditions. We propose the following three pulsatile indices for evaluating the microcirculation condition from the normalized pressure and flux segment with a synchronized-averaging method: peak delay time (PDT), pressure rise time and flux rise time (FRT). The abdominal aortic blood pressure and renal cortex flux (RCF) signals were measured in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). The mean value of the RCF did not differ between SHR and WKY. However, the PDT was longer in SHR (87.14 +/- 5.54 ms, mean +/- SD) than in WKY (76.92 +/- 2.62 ms; p < 0.001). The FRT was also longer in SHR (66.56 +/- 1.98 ms) than in WKY (58.02 +/- 1.77 ms; p < 0.001). We propose that a new dimension for comparing the LDF signals, which the results from the present study show, can be used to discriminate RCF signals that cannot be discriminated using traditional methods.

Population structure of wild bananas, Musa balbisiana, in China determined by SSR fingerprinting and cpDNA PCR-RFLP

Both demographic history and dispersal mechanisms influence the apportionment of genetic diversity among plant populations across geographical regions. In this study, phylogeography and population structure of wild banana, Musa balbisiana, one of the progenitors of cultivated bananas and plantains in China were investigated by an analysis of genetic diversity of simple sequence repeat (SSR) fingerprint markers and cpDNA PCR-RFLP. A chloroplast DNA (cpDNA) genealogy of 21 haplotypes identified two major clades, which correspond to two geographical regions separated by the Beijiang and Xijiang rivers, suggesting a history of vicariance. Significant genetic differentiation was detected among populations with cpDNA markers, a result consistent with limited seed dispersal in wild banana mediated by foraging of rodents. Nuclear SSR data also revealed significant geographical structuring in banana populations. In western China, however, there was no detected phylogeograpahical pattern, possibly due to frequent pollen flow via fruit bats. In contrast, populations east of the Beijiang River and the population of Hainan Island, where long-range soaring pollinators are absent, are genetically distinct. Colonization-extinction processes may have influenced the evolution of Musa populations, which have a metapopulation structure and are connected by migrating individuals. Effective gene flow via pollen, estimated from the nuclear SSR data, is 3.65 times greater than gene flow via seed, estimated from cpDNA data. Chloroplast and nuclear DNAs provide different insights into phylogeographical patterns of wild banana populations and, taken together, can inform conservation practices.

Effects of whole-body mechanical stimulation at double the heart rate on the blood pressure waveform in rats

The effects of mechanical stimulation on hemodynamics, such as due to mechanotransduction in vascular endothelial cells, have been widely discussed recently. We previously proposed a resonance model in which the arterial system is treated as a pressure-transmitting system, and suggested that the application of external mechanical stimulation with frequencies near the heart rate (HR) or harmonics thereof can be sensed by the arterial system and induce hemodynamic changes. In this study, we monitored the effects of external mechanical stimulation at a frequency of double the HR on BPW (blood pressure waveform), HRV (HR variability) and BPHV (blood-pressure-harmonics variability) in rats. A motor beating a waterbed mattress was used to generate pressure variations of 0.5 mmHg to apply onto the rats. The experiments were performed on three groups of rats with different beating frequencies: (A) double the HR, (B) 5% deviation from double the HR and (C) 1.5 times the HR. The experimental procedure was a 15 min control period followed by application of the mechanical stimulation for 15 min and further recording for 15 min (OFF period). During the OFF period, the amplitude of the second harmonic in the BPW significantly increased by >5% in group A with decreased HRV and BPHV. The second harmonic increased less in group B, and decreased in group C. The increase in the second-harmonic amplitude in group A may be due to the filtering properties of the renal arterial structure. This mechanism could be used to improve the local blood supply into the kidneys, and hence provide a new treatment modality for some important diseases, such as renal hypertension or nephrosis.

Validation of fermentation processes

The ability to prepare consistent biopharmaceutical products depends extensively on possession of banked and characterized cell substrates and on development of production processes which can be validated. While the attributes that define cell characterization have been extensively detailed by ICH and the regulatory agencies in the past decade, little has been specified regarding process validation for biological processes. The extent to which validation concepts can be applied to biological processes varies depending on the nature of the process, the nature of the product, and the level of knowledge regarding the relationship between process parameters and product quality. Expectations concerning the rigour of the validation programme should be adjusted accordingly. There is no single approach that is appropriate for all processes and products. At a minimum, there should be an attempt to define which process parameters are critical, and to focus the attention of validation efforts on these parameters.

Influencing the heart rate of rats with weak external mechanical stimulation

The ventricular-arterial coupling is assumed to minimize the expenditure of cardiac energy. From the conjecture of the resonance theory, the arterial system transmits pressure waves and resonates with the heartbeat, therefore, the arterial system is similar to a mechanical resonator. Theoretically, the heart rate can be paced with weak external mechanical stimulation and corresponding blood pressure changes can be observed. A waterbed was activated to generate 0.5-mmHg pressure vibrations as a stimulus and the rate was set to deviate 5% from the control heart rate. Among 13 studies on seven rats, the linear regression between X (stimulation frequency--control heart rate) and Y (actual changes of the heart rate) is Y = 0.992X = 0.062 (Hz) with a correlation coefficient of 0.97 (Y = X implies complete steering). The intercorrelation coefficient between the change in mean blood pressure and the heart rate was 0.79. The study showed that this weak mechanical stimulation influences the heart rate, and the blood pressure changes according to the heart rate. Cardiovascular optimization and the resonance theory may explain the way one may regulate the heart rate and the blood pressure of humans noninvasively in the future.

Crystallization and preliminary crystallographic studies of a ribosomal protein L30e from the hyperthermophilic archaeonThermococcus celer

Ribosomal protein L30e from the hyperthermophilic archaeon Thermococcus celer is a good model for the study of the thermostability of proteins. It has been overexpressed, purified and crystallized using the hanging-drop vapour-diffusion method using PEG 8000 as precipitant at 290 K. The crystal belongs to the hexagonal space group P6(1)/P6(5), with unit-cell parameters a = b = 48.32, c = 86.42 A. The asymmetric unit contains a single molecule of L30e, with a corresponding crystal volume per protein mass (V(M)) of 2.68 A(3) Da(-1) and a solvent content of 54%. A complete data set diffracting to 1.96 A resolution was collected from a single crystal at 100 K.

Structure of the C-terminal sterile alpha-motif (SAM) domain of human p73 alpha

p73 is a homologue of the tumour suppressor p53 and contains all three functional domains of p53. The alpha-splice variant of p73 (p73 alpha) contains near its C-terminus an additional structural domain known as the sterile alpha-motif (SAM) that is probably responsible for regulating p53-like functions of p73. Here, the 2.54 A resolution crystal structure of this protein domain is reported. The crystal structure and the published solution structure have the same five-helix bundle fold that is characteristic of all SAM-domain structures, with an overall r.m.s.d. of 1.5 A for main-chain atoms. The hydrophobic core residues are well conserved, yet some large local differences are observed. The crystal structure reveals a dimeric organization, with the interface residues forming a mini four-helix bundle. However, analysis of solvation free energies and the surface area buried upon dimer formation indicated that this arrangement is more likely to be an effect of crystal packing rather than reflecting a physiological state. This is consistent with the solution structure being a monomer. The p73 alpha SAM domain also contains several interesting structural features: a Cys-X-X-Cys motif, a 3(10)-helix and a loop that have elevated B factors, and short tight inter-helical loops including two beta-turns; these elements are probably important in the normal function of this domain.

[Studies of FISH and karyotype of Gossypium barbadense]

Based on the fluorescent in situ hybridization (FISH) of somatic chromosome of Gossypium barbadense with the probe of genomic DNA (gDNA) of Gossypium arboreum, two sets of chromosomes were easily distinguished by signals hybridized or not. The FISH directly proved that G. barbadense originated from two different diploid species, but was not in concordance with the former point that every chromosome of A sub-genome of tetraploid species was bigger than that of other sub-genome (D genome). The karyotype formula of G. barbadense based on its FISH was 2n = 4x = 52 = 38 m + 14sm(6sat). There were three pairs of satellite chromosomes which were all sm types. Their satellites located in short arms but originated differently from their chromosomes of sub-genome. Fragment translocations occured in the long arms of homologous chromosomes of number 5, 6 and 9 of A sub-genome. It was suggested that the translated fragments come from D sub-genome. The fragments are fairly large with the relative lengths of 19.21%, 17.69% and 12.88% of their whole chromosomes, respectively. At least five pairs of chromosomes in D sub-genome show some hybridized signals of gDNA probe of G. arboreum in their centromere regions, which indicated that there would be chromatin introgressions from A sub-genome.

Influence of spleen meridian herbs on the harmonic spectrum of the arterial pulse

Pulse analysis is a powerful method in Chinese medicine. We suggest that the effect of herbal medicine is to redistribute the blood to organs and meridians. In this report, by injecting extracts into rats and then analyzing the blood pressure wave measured at the caudate arteries, we studied eight important spleen meridian related herbs: They were Semen Lablab, Fructus Amomi Globosi, Rhizoma Atractylodis Macrocephalae, Rhizoma Atractylodis, Tuber Pinelliae, Radix Codonopsitis, Pericarpium Aurantii and Rhizoma Polygonati. All eight herbs increased the intensity of the 3rd harmonic (C3) of the pressure pulse which is correlated to the spleen and spleen meridian, as described in traditional Chinese medical literature. All of them also increased the 2nd harmonic (which is correlated to the kidney and the kidney meridian) as well as decreased the heart load (DC term of pressure wave, C0). Tuber Pinelliae, Radix Codonopsitis, Pericarpium Aurantii and Rhizoma Polygonati decreased the 1st harmonic (correlated to the liver meridian) significantly, while Rhizoma Atractylodis Macrocephalae only decreased C1 slightly. Except for Semen Lablab, all the others decreased the intensity of the 5th (stomach meridian) and the 7th harmonics. The effects of kidney herbs: Cortex Eucommiae and Radix Achyranthis were also shown for comparison.

Interaction between HIV type 1 glycoprotein 120 and CXCR4 coreceptor involves a highly conserved arginine residue in hypervariable region 3

Several seven-transmembrane chemokine receptors are known to function as entry coreceptors for human immunodeficiency virus type 1. CCR5 and CXCR4 are the major coreceptors for non-syncytium-inducing (NSI) and syncytium-inducing (SI) viruses, respectively. During the natural course of infection, the emergence of variants with a phenotypic transition from NSI to SI and rapid disease progression is associated with expanded coreceptor usage to CXCR4. Characteristic amino acids at several positions in the hypervariable region 3 (V3) of gp120 have been linked to CXCR4 utilization. Previously, we reported that a highly conserved arginine residue of V3 played an important role in CCR5 utilization. In this study, the possible involvement of the same arginine residue in CXCR4 utilization was investigated. Amino acid substitutions introduced to this arginine on R5X4 viruses were found to have a significant effect on their utilization of CXCR4. These results, taken together with those reported previously, suggest that this highly conserved arginine may contribute to the functional convergence of chemokine coreceptor utilization by human immunodeficiency viruses and may represent a unique target for future antiviral design.

Quantitative competitive reverse transcription-PCR for quantification of dengue virus RNA

A quantitative competitive reverse transcription-PCR assay was developed to quantify dengue virus RNA in this study. The main features include a primer pair targeting a highly conserved region in the capsid and the addition of competing RNA that contains an internal deletion to provide a stringent internal control for quantification. It can be utilized to quantify RNA isolated from the four dengue virus serotypes but not RNA isolated from other flaviviruses, including Japanese encephalitis virus and hepatitis C virus, both prevalent in Asia. It can also be used to quantify dengue virus RNA isolated from the plasma of infected individuals. The sensitivity of the assay was estimated to be 10 to 50 copies of RNA per reaction, and twofold differences in virus titer are distinguishable. This assay is a convenient, sensitive, and accurate method for quantification and can be used to further understanding of the pathogenesis of dengue virus infection.

Molecular biology of human immunodeficiency virus type 1

Since the discovery of human immunodeficiency virus (HIV) as the etiologic agent of acquired immune deficiency syndrome (AIDS) more than a decade ago, tremendous progress has been made in various aspects of this virus and its interplay with the host immune system. The advent of potent combination therapy has made it possible to achieve effective and durable control of HIV-1 replication in vivo, yet the persistence of the latent reservoirs pose a new challenge. The recent identifications of several cellular proteins interacting with different viral gene products have not only shed new insights into our understanding of the HIV-1 and the host cell biology, but also provided the bases for developing novel strategies to block HIV-1 replication. It is from this perspective that we review the current understanding of the molecular mechanisms governing the HIV-1 life cycle.

Determination of human immunodeficiency virus type 1 subtypes in Taiwan by vpu gene analysis

The genetic diversity of human immunodeficiency virus (HIV) type 1 (HIV-1) has been characterized mainly by analysis of the env and gag genes. Information on the vpu genes in the HIV sequence database is very limited. In the present study, the nucleotide sequences of the vpu genes were analyzed, and the genetic subtypes determined by analysis of the vpu gene were compared with those previously determined by analysis of the gag and env genes. The vpu genes were amplified by nested PCR of proviral DNA extracted from 363 HIV-1-infected individuals and were sequenced directly by use of the PCR products. HIV-1 subtypes were determined by sequence alignment and phylogenetic analysis with reference strains. The strains in all except one of the samples analyzed could be classified as subtype A, B, C, E, or G. The vpu subtype of one strain could not be determined. Of the strains analyzed, genetic subtypes of 247 (68.0%) were also determined by analysis of the env or gag gene. The genetic subtypes determined by vpu gene analysis were, in general, consistent with those determined by gag and/or env gene analysis except for those for two AG recombinant strains. All the strains that clustered with a Thailand subtype E strain in the vpu phylogenetic analyses were subtype E by env gene analysis and subtype A by gag gene analysis. In summary, our genetic typing revealed that subtype B strains, which constituted 73.8% of all strains analyzed, were most prevalent in Taiwan. While subtype E strains constituted about one-quarter of the viruses, they were prevalent at a higher proportion in the group infected by heterosexual transmission. Genetic analysis of vpu may provide an alternate method for determination of HIV-1 subtypes for most of the strains, excluding those in which intersubtype recombination has occurred.

Crystallization and preliminary crystallographic studies of a SAM domain at the C-terminus of human p73alpha

p73 is a recently discovered homologue of the tumour suppressor p53 and contains all three functional domains of p53. The alpha-splice variant of p73 (p73alpha) contains an additional structural domain near its C--terminus that has sequence homology with the sterile alpha-motif (SAM) domain. This domain is considered to be responsible for mediating protein-protein interactions. Pyramidal crystals of human p73alpha SAM domain were obtained by the hanging-drop vapour-diffusion method with ammonium dihydrogen orthophosphate as the precipitant. The crystals diffract to 2.54 A resolution and belong to the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = b = 32.02, c = 133.84 A. The structure was solved by molecular replacement using the NMR structure of the same protein as the search model.

Effect of length on the fundamental resonance frequency of arterial models having radial dilatation

The pressure wave moving along an elastic artery filled with blood was examined as a moving Windkessel having a natural oscillation angular frequency nu 0 and a damping coefficient b. The radial directional motion for an element of the wall segment and the adherent fluid was considered. This equation was solved with conditions at both ends of an artery of length L. An external impulse force was applied at one end and a static pressure Po at the other. Analytic solution allowed only certain oscillation modes of resonance frequencies fn, where fn2 = a + cnL-2 with [formula: see text] and V infinity is the high frequency phase velocity. The relationship between f0 and L was examined experimentally for tubes constructed of latex, rubber, or dissected aorta. The effect of raising the static pressure P0 or increasing the tension in the tube was consistent with the prediction. The hypertension that accompanies an augmentation in arterial wall and the association between the heart rate and the mean blood pressure were discussed.

Hypervariable region 3 residues of HIV type 1 gp120 involved in CCR5 coreceptor utilization: therapeutic and prophylactic implications

Crystallographic characterization of a ternary complex containing a monomeric gp120 core, parts of CD4, and a mAb, revealed a region that bridges the inner and outer domains of gp120. In a related genetic study, several residues conserved among primate lentiviruses were found to play important roles in CC-chemokine receptor 5 (CCR5) coreceptor utilization, and all but one were mapped to the bridging domain. To reconcile this finding with previous reports that the hypervariable region 3 (V3) of gp120 plays an important role in chemokine coreceptor utilization, elucidating the roles of various V3 residues in this critical part of the HIV type 1 (HIV-1) life cycle is essential. Alanine-scanning mutagenesis was carried out to identify V3 residues critical for CCR5 utilization. Our findings demonstrated that several residues in V3 were critical to CCR5 utilization. Furthermore, these residues included not only those conserved across HIV-1 subtypes, but also those that varied among HIV-1 subtypes. Although the highly conserved V3 residues may represent unique targets for antiviral designs, the involvement of variable residues raises the possibility that antigenic variation in the coreceptor binding domain could further complicate HIV-1 vaccine design.

Stability and folding of the tumour suppressor protein p16

The tumour suppressor p16 is a member of the INK4 family of inhibi tors of the cyclin D-dependent kinases, CDK4 and CDK6, that are involved in the key growth control pathway of the eukaryotic cell cycle. The 156 amino acid residue protein is composed of four ankyrin repeats (a helix-turn-helix motif) that stack linearly as two four-helix bundles resulting in a non-globular, elongated molecule. The thermodynamic and kinetic properties of the folding of p16 are unusual. The protein has a very low free energy of unfolding, Delta GH-2O/D-N, of 3.1 kcal mol-1 at 25 degreesC. The rate-determining transition state of folding/unfolding is very compact (89% as compact as the native state). The other unusual feature is the very rapid rate of unfolding in the absence of denaturant of 0.8 s-1 at 25 degreesC. Thus, p16 has both thermodynamic and kinetic instability. These features may be essential for the regulatory function of the INK4 proteins and of other ankyrin-repeat-containing proteins that mediate a wide range of protein-protein interactions. The mechanisms of inactivation of p16 by eight cancer-associated mutations were dissected using a systematic method designed to probe the integrity of the secondary structure and the global fold. The structure and folding of p16 appear to be highly vulnerable to single point mutations, probably as a result of the protein's low stability. This vulnerability provides one explanation for the striking frequency of p16 mutations in tumours and in immortalised cell lines.

Role of the CCR5 delta 32 allele in resistance to HIV-1 infection in west Africa

OBJECTIVE

To determine the frequency of the mutant CCR5 delta 32 allele in high-risk HIV-seronegative Africans as compared with the general African population, and to assess its in vitro protective efficacy against HIV-1 infection.

STUDY DESIGN

In the homozygous form, the CCR5 delta 32 allele confers resistance to macrophage-tropic (M-tropic) strains of HIV-1. Assuming that genetic characteristics favoring HIV resistance would prevail in a high-risk HIV-seronegative population, we examined the CCR5 genotypes of female commercial sex workers (CSWs) from Dakar, Senegal, who have remained uninfected for an elongated period.

METHODS

The CCR5 genetic profile of study participants was determined by polymerase chain reaction (PCR) amplification of genomic DNA followed by sequencing. Peripheral blood mononuclear cells (PBMCs) were infected with different strains of HIV-1 and monitored by p24 enzyme-linked immunosorbent assay (ELISA).

RESULTS

We confirmed the presence of two CCR5wt/delta 32 genotypes among 139 individuals (1.44%). PBMCs from these 2 heterozygous individuals were also found to be less susceptible to in vitro infection by an M-tropic HIV-1 primary isolate.

CONCLUSIONS

Evidence was found of an increased prevalence of the CCR5wt/delta 32 genotype in a high-risk HIV-seronegative cohort in West Africa. Furthermore, reduced susceptibility to HIV-1 infection among heterozygous individuals supports a role for 32-bp CCR5 deletion in HIV-1 resistance.

Liu-wei-dihuang: a study by pulse analysis

Pulse analysis method was used in studying the traditional Chinese formula Liu-Wei-Dihuang as well as five of its main components (Rehmannia glutinosa, Cornus officinalis, Paeonia Suffruticosa, Poria cocos and Alisma plantogo-aquatica var oriental). Based on our recently developed resonance theory, we tried to elucidate the mechanism and mutual reactions of these meridian related herbs. Hot water herbal extracts were injected intraperitoneally into rats and the pressure pulse spectrum at the caudate artery was measured. The results of this study indicated that Liu-Wei-Dihuang mildly increased blood flow to meridians with lower resonance frequency: namely the liver C1, the kidney C2 and the spleen C3; but decreased blood flow to the higher resonance frequency organs and meridians: the lung C4, the stomach C5, the gall bladder C6, and the bladder C7. It also decreased the heart load C0. All of the five herb components increased blood flow to the kidney C2 and the spleen C3; but their effects on the high frequency organs varied. Alisma plantogo-aquatica var. oriental decreased the C0, C5, C6, C7; Poria cocos decreased C1, C4, C5, C6; Rehmannia glutinosa, Paeonia Suffruticosa decreased C0, C4, C5, C6, C7; Cornus officinalis increased C4 but decreased C0, C5, C6, C7.

CCR5 coreceptor utilization involves a highly conserved arginine residue of HIV type 1 gp120

The seven-transmembrane CCR5 was recently found to double as a coreceptor for a genetically diverse family of human and nonhuman primate lentiviruses. Paradoxically, the main region of the envelope protein believed to be involved in CCR5 utilization was mapped to hypervariable region 3, or V3, of the envelope glycoprotein gp120. In this study, we addressed the question of whether functional convergence in CCR5 utilization is mediated by certain V3 residues that are highly conserved among HIV type 1 (HIV-1), HIV type 2, and simian immunodeficiency virus. Site-directed mutagenesis carried out on three such V3 residues revealed that the Arg-298 of HIV-1 gp120 has an important role in CCR5 utilization. In contrast, no effect was observed for the other residues we tested. The inability of Arg-298 mutants to use CCR5 was not attributed to global alteration of gp120 conformation. Neither the expression, processing, and incorporation of mutant envelope proteins into virions, nor CD4 binding were significantly affected by the mutations. This interpretation is further supported by the finding that alanine substitutions of five residues immediately adjacent to the arginine residue had no effect on CCR5 utilization. Taken together, our data strongly suggests that the highly conserved Arg-298 residue identified in the V3 of HIV-1 has a significant role in CCR5 utilization, and may represent an unusually conserved target for future anti-viral designs.

Pulse spectrum study on the effect of sie-zie-tang and Radix aconiti

Extracts of the traditional Chinese formula Sie-Zie-Tang as well as one of its main components, Radix Aconiti were injected into rats intraperitoneally to observe pressure wave spectrum changes at the caudate artery. We found that Radix Aconiti decreased the C0 (DC term of the pulse), C5 and C6 (the harmonic proportions of the 5th and the 6th harmonic), but increased C2 and C3 (the harmonic proportions of the second and the third harmonic) significantly. For Sie-Zie-Tang, the increases of C2, C3, and C4 were accompanied by the decreasing of C0. The decreases of C5, C6 were small and not significant. The additional ingredients in the formula reduce toxic side effects (arrhythmia or heart failure caused by faster and stronger heart beat) due to Radix Aconiti. For human subjects, low dose Sie-Zie-Tang tends to normalize the Fourier components of the pressure wave. Orally taking the formula elevates the harmonic proportion of the harmonic that is lower than normal, but suppresses the higher one. Our results provides a possible mechanism for heart meridian related herbs. It strengthens heart beats, and normalizes energy distribution to different meridians. The study on Sie-Zie-Tang reveals another formula construction to reduce toxic side effects.

Dominant transformation by mutated human ras genes in vitro requires more than 100 times higher expression than is observed in cancers

The gene-mutation-cancer hypothesis holds that mutated cellular protooncogenes, such as point-mutated proto-ras, "play a dominant part in cancer," because they are sufficient to transform transfected mouse cell lines in vitro [Alberts, B., Bray, D., Lewis, J., Raff, M., Roberts, K. & Watson, J. D. (1994) Molecular Biology of the Cell (Garland, New York)]. However, in cells transformed in vitro mutated human ras genes are expressed more than 100-fold than in the cancers from which they are isolated. In view of the discrepancy between the very low levels of ras transcription in cancers and the very high levels in cells transformed in vitro, we have investigated the minimal level of human ras expression for transformation in vitro. Using point-mutated human ras genes recombined with different promoters from either human metallothionein-IIA or human fibronectin or from retroviruses we found dominant in vitro transformation of the mouse C3H cell line only with ras genes linked to viral promoters. These ras genes were expressed more than 120-fold higher than are native ras genes of C3H cells. The copy number of transfected ras genes ranged from 2-6 in our system. In addition, nondominant transformation was observed in a small percentage (2-7%) of C3H cells transfected with ras genes that are expressed less than 20 times higher than native C3H ras genes. Because over 90% of cells expressing ras at this moderately enhanced level were untransformed, transformation must follow either a nondominant ras mechanism or a non-ras mechanism. We conclude that the mutated, but normally expressed, ras genes found in human and animal cancers are not likely to "play a dominant part in cancer." The conclusion that mutated ras genes are not sufficient or dominant for cancer is directly supported by recent discoveries of mutated ras in normal animals, and in benign human tissue, "which has little potential to progress" [Jen, J., Powell, S. M., Papadopoulos, N., Smith, K. J., Hamilton, S. R., Vogelstein, B. & Kinzler, K. W. (1994) Cancer Res. 54, 5523-5526]. Even the view that mutated ras is necessary for cancer is hard to reconcile with (i) otherwise indistinguishable cancers with and without ras mutations, (ii) metastases of the same human cancers with and without ras mutations, (iii) retroviral ras genes that are oncogenic without point mutations, and (iv) human tumor cells having spontaneously lost ras mutation but not tumorigencity.

Genetic variation within human immunodeficiency viruses generates rapid changes in tropism, virulence, and transmission

The human immunodeficiency viruses (HIV-1) undergo high rates of variation. Only a few point mutations in the envelope gene are required to switch the tropism of HIV-1 from a growth preference for monocytes to lymphocytes or to acquire lytic properties for rapid killing of infected T4 lymphocytes. Since heterosexual transmission efficiency is high for HIV-1's that are most prevalent in Africa or Asia, but low for HIV-1 B, which dominates in the US and western Europe, we asked whether African and Asian viruses had a particular tropism for cells of the reproductive tract. Langerhans' cells (LC), showed only minimal susceptibility to infection with HIV-1B from the US, but substantially greater sensitivity for infections by HIV-1 E and HIV-1 C, subtypes that predominate in Asia and Africa.

Pattern of gp120 sequence divergence linked to a lack of clinical progression in human immunodeficiency virus type 1 infection

Differential rates of AIDS development and/or T4 lymphocyte depletion in HIV-1-infected individuals remain unexplained. The hypothesis that qualitative differences in selection pressure in vivo may account for different rates of disease progression was addressed in nine eligible study participants from a cohort of 315 homosexual men who have been followed since 1985. Disproportionately fewer changes in variable regions and more in C3 of gp12O were found to be significantly associated with slower disease progression. Our finding provides the first example to demonstrate that differential selection pressure related to the emergence of HIV-1 variants is associated with long term nonprogression. Candidate vaccines that elicit strong selection pressure on C3 of gp120 are likely to provide better protection than those targeting variable regions.

Identification of the envelope V3 loop as a determinant of a CD4-negative neuronal cell tropism for HIV-1

Some neuronal-derived CD4-negative cells are susceptible to infection with human immunodeficiency virus type 1 (HIV-1). Galactosyl ceramide is an alternate receptor for HIV-1 that appears to bind in vitro to the C2, V3, V4, and V5 regions of gp120. Amino acid variation in the V3 loop of HIV-1 affects cellular tropism in CD4-positive cells, but its effect on CD4-negative cells has not been fully analyzed. Here, we describe the effect of amino acid changes in V3 on the HIV-1 infection of a CD4-negative neuronal cell line, SK-N-MC. The sequence of the V3 domain was found to dramatically alter virus infectivity. Furthermore, a gp120 V3 loop neutralizing monoclonal antibody blocked HIV-1 infection of SK-N-MC cells. This data suggests that V3 may also serve as a primary viral determinant for infectivity of CD4-negative cells.

Pulse spectrum analysis of chemical factory workers with abnormal blood test

Double blind tests to check the correlation between pulse diagnosis and liver function tests were performed. Blood tests including T-Bil, D-Bil, SGOT and SGPT of 70 chemical factory workers were compared with pulse analysis. Special attention was paid to the indicators of liver and lung meridians for pulse diagnosis. It was found that using the criterion (1) C1 > or = 3+ and C1 + C4 > or = 4+ (hyperfunction) and (2) C1 < or = 3-(hypofunction) as abnormal liver meridian (for C1, every 5% above normal give one +, every 5% below normal give one-; for C4 every 10% above normal give one +, every 10% below normal give one -). The correlation or agreement between the blood tests and the pulse diagnosis was very high (noncorrelation chance checked by X2-test, P < 0.001, degree of agreement checked by Kappa test Ka = 0.61 which means a substantial relationship). Suggestions such as more tests, more criteria and precautions for future study are also proposed.

Pulse spectrum analysis of hospital patients with possible liver problems

Pulse diagnosis were performed on 85 patients who came to the hospital for liver and gall-bladder problems. Correlation between liver tests, which include T-Bil, D-Bil, SGOT, SGPT, ZTT, Alp, gamma-GT, Cho, Alb, and ultra sound scanning, and pulse diagnosis were analyzed. 77 out of 85 subjects showed abnormal liver tests. We used the following 5 criteria for pulse diagnosis as liver abnormality to test the correlation: (1) C1 > or = 3+ and C1 + C4 > or = 4+ or C1 + C6 > or = 4 (in intensity); (2) C1 < or = 3 (in intensity); (3) C6 > or = 3 and C1 + C6 > or = 4 (in intensity); (4) C6 < or = -2 (in intensity) and C6 < or = -2 (in the phase) and (5) C1 > or = 2 C3 < or = -2 (in intensity) or C3 < or = -2 (in the phase). For C1 (liver) every 5% above normal was given one "+," every 5% below normal was given one "-." For C3 (spleen), C4 (lung), C6 (gall-bladder), every 10% above normal was given one "+,", every 10% below normal was given one "-." For the phase, every 10% delay in the traveling speed was given one "-." When considering only the "+" and "-" states and neglecting the quantity of "+" and "-," there are 2(11) (from intensity) x 2(11) (from phase), which equal 2048 x 2048 possible states in the pulse analysis. We considered only 5 criteria for liver abnormality; the correlation was still very high, p < 0.0002, kappa = 0.64. It strongly suggests that meridian theory and pulse diagnosis have physiological and pathological importance.

Effect of acupuncture at tai-tsih (K-3) on the pulse spectrum

The frequency specific acupuncture effect on Tai-Tsih (K-3) was examined by investigating pulse variations at the radial artery. The harmonic proportions of the 2nd, 3rd, and the 4th harmonics were increased but the 5th, 6th and 9th harmonics were decreased significantly. The phase angles of all except the 2nd harmonic were increased (wave propagated slower). These results are compared with the frequency specific acupuncture effect on Tsu-San-Li (St-36) which we reported previously (Wang et al., 1995a). This study solidified the weak coupling resonance theory, which successfully explains these frequency specific effects as well as the acupuncture mechanism.

Single amino acid substitution in constant region 1 or 4 of gp120 causes the phenotype of a human immunodeficiency virus type 1 variant with mutations in hypervariable regions 1 and 2 to revert

The second major cysteine loop of human immunodeficiency virus type 1 envelope glycoprotein gp120 contains 5 to 11 consensus N-linked glycosylation sites, which is disproportionately higher than the number of such sites found in other regions of gp120. Amino acid substitutions introduced at three of six N-linked glycosylation sites in this region of an infectious molecular clone, HXB2, resulted in severe impairment of virus infectivity. Isolation and genetic characterization of a revertant of this mutant revealed an isoleucine-for-valine substitution at position 84 in constant region 1 and an isoleucine-for-methionine substitution at position 434 in constant region 4. Further mutational analysis indicated that either isoleucine substitution was sufficient to confer the revertant phenotype. These findings demonstrate that V1/V2 not only functionally interacts with C4, as previously reported, but also interacts with C1. The observation that compensatory changes do not involve regeneration of N-linked glycosylation sites in the second major cysteine loop suggests that replication of human immunodeficiency virus type 1 in vitro is independent of the presence of a disproportionate number of N-linked glycosylation sites within this loop.

The prandial effect on the pulse spectrum

The prandial effect on the pulse spectrum of the radial artery was studied. Ingestion greatly affected the spectrum of the pressure pulse. For most of the tested subjects, the harmonic proportions of the 2nd and the 4th harmonic increased significantly after ingestion, however a decreasing effect was found on the 5th, 6th, 7th, 8th, 9th harmonics. The spectrum became stable from half hour after ingestion and last 3 to 4 hours. From these results, a reliable pulse diagnosis is therefore suggested to be done in the period when the pulse spectrum is stable; physiological significance of these postprandial phenomena is also discussed.

Product inhibition of the recombinant CelS, an exoglucanase component of the Clostridium thermocellum cellulosome

CelS is the most abundant subunit and an exoglucanase component of the Clostridium thermocellum cellulosome, multicomponent cellulase complex. The product inhibition pattern of CelS was examined using purified recombinant CelS (rCelS) produced in Escherichia coli. The rCelS activity on cellopentaose was strongly inhibited by cellobiose. The rCelS activity was also inhibited by lactose. Glucose was only marginally inhibitory. Cellobiose appeared to inhibit the rCelS activity through a competitive mechanism. The inhibition was relieved when beta-glucosidase was added, presumably because of the conversion of cellobiose into glucose. These hydrolysis product inhibition patterns are consistent with those of the crude enzyme (cellulosome), suggesting that CelS is a rate-limiting factor in the activity of the cellulosome.

Exoglucanase activities of the recombinant Clostridium thermocellum CelS, a major cellulosome component

The recombinant CelS (rCelS), the most abundant catalytic subunit of the Clostridium thermocellum cellulosome, displayed typical exoglucanase characteristics, including (i) a preference for amorphous or crystalline cellulose over carboxymethyl cellulose, (ii) an inability to reduce the viscosity of a carboxymethyl cellulose solution, and (iii) the production of few bound reducing ends on the solid substrate. The hydrolysis products from crystalline cellulose were cellobiose and cellotriose at a ratio of 5:1. The rCelS activity on amorphous cellulose was optimal at 70 degrees C and at pH 5 to 6. Its thermostability was increased by Ca2+. Sulfhydryl reagents had only a mild adverse effect on the rCelS activity. Cellotetraose was the smallest oligosaccharide substrate for rCelS, and the hydrolysis rate increased with the substrate chain length. Many of these properties were consistent with those of the cellulosome, indicating a key role for CelS.

Effect of acupuncture at Tsu San Li (St-36) on the pulse spectrum

Effect of acupuncture at Tsu San Li (St-36) was examined by investigating the pulse variation of the radial artery. Our results indicated that acupuncture at Tsu San Li has a specific effect on the Fourier components of the pulse. The harmonic proportions were redistributed (C2, C4 decreased, C5, C6, C8 and C9 increased), and the phase angle of the 5th and 8th harmonic waves were decreased (propagating faster). This specific frequency effect was not found when acupuncture needle was applied on a non-acupuncture point. These results can be explained by the resonance theory, which provides a scientific explanation of the acupuncture effect from the hemodynamic view point.

Collective effect of a Chinese formula--a study of xiao-jian-zhong-tang

Components of a traditional Chinese medicine formula Xiao-Jian-Zhong-Tang were divided into three groups: (1) Radix Paeoniae Lactiflorae, (2) Radix Astragali, and (3) Cinnamon twig, Radix Glycyrrhizae, Fructus jujubae and Saccharum Granorum. Extracts of each group were injected into rats to observe the blood pressure wave spectrum changes at the caudate artery. The whole formula was also extracted and injected into rats to monitor blood pressure wave spectrum changes. Each group has its own effect on the Fourier components of the blood pressure wave. The meridian effects of these herbs are the same as described in the Chinese medical literature, if we consider each meridian in resonance with a specific Fourier component. The whole formula when injected into rats had an effect on the Fourier components of the blood pressure wave similar to the linear combination of individual effect of the three herb groups when used separately. This may be the fundamental idea behind formula construction.

The highly conserved aspartic acid residue between hypervariable regions 1 and 2 of human immunodeficiency virus type 1 gp120 is important for early stages of virus replication

Between hypervariable regions V1 and V2 of human immunodeficiency virus type 1 (HIV-1) gp120 lies a cluster of relatively conserved residues. The contribution of nine charged residues in this region to virus infectivity was evaluated by single-amino-acid substitutions in an infectious provirus clone. Three of the HIV-1 mutants studied had slower growth kinetics than the wild-type virus. The delay was most pronounced in a mutant with an alanine substituted for an aspartic acid residue at position 180. This aspartic acid is conserved by all HIV-1 isolates with known nucleotide sequences. Substitutions with three other residues at this position, including a negatively charged glutamic acid, all affected virus infectivity. The defect identified in these mutants suggests that this aspartic acid residue is involved in the early stages of HIV-1 replication.

Cloning and expression of the Clostridium thermocellum celS gene in Escherichia coli

Clostridium thermocellum ATCC 27405 produces an extremely complicated multi-component cellulase aggregate (cellulosome) highly active on crystalline cellulose. From the cellulosome, two subunits, CelS (or Ss; M(r) = 82,000) and CelL (or SL, CipA; M(r) = 250,000), have been identified as essential for crystalline cellulose degradation [Wu et al. (1988) Biochemistry 27:1703]. We have determined the DNA sequence of the celS gene from four cloned DNA fragments encompassing this gene [Wang et al. (1993) J Bacteriol 175:1293]. To express the entire celS gene in Escherichia coli, the celS structural gene was amplified by the polymerase chain reaction (PCR) employing the PCR primers corresponding to sequences flanking the desired gene. This PCR product (2.1 x 10(3) bases; 2.1 kb) was cloned into an E. coli expression vector pRSET B. Subsequent expression of the cloned gene resulted in a fusion protein (rCelS; M(r) = 86,000) as inclusion bodies. The rCelS protein was recognized specifically by an anti-CelS antiserum in a Western blot analysis. The inclusion bodies were purified and solubilized in 5 M urea. The refolded rCelS produced very little reducing sugar from carboxymethylcellulose. However, it showed a higher activity on the crystalline cellulose (Avicel) and an even higher activity on phosphoric-acid-swollen Avicel. These results indicate that the CelS is an exoglucanase.