Enhancement patterns of potassium on nitrogen transport and functional genes in cotton vary with nitrogen levels

The application of potassium (K) in conjunction with nitrogen (N) has been shown to enhance N use efficiency. However, there is still a need for further understanding of the optimal ratios and molecular regulatory mechanisms, particularly in soil-cotton systems. Here, a field trial was conducted, involving varying rates of N and K, alongside pot and hydroponic experiments. The objective was to assess the impact of N-K interaction on the absorption, transport and distribution of N in cotton. The results showed that K supply at 90 and 240 kg ha-1 had a beneficial impact on N uptake and distribution to both seed and lint, resulting in the highest N use efficiency ranging from 22% to 62% and yield improvements from 20% to 123%. The increase in stem and root diameters, rather than the quantify of xylem vessels and phloem sieve tubes, facilitated the uptake and transport of N due to the provision of K. At the molecular level, K supply upregulated the expression levels of genes encoding GhNRT2.1 transporter and GhSLAH3 channel in cotton roots to promote N uptake and GhNRT1.5/NPF7.3 genes to transport N to shoot under low-N conditions. However, under high-N conditions, K supply induced anion channel genes (GhSLAH4) of roots to promote N uptake and genes encoding GhNRT1.5/NPF7.3 and GhNRT1.8/NPF7.2 transporters to facilitate NO3- unloading from xylem to mesophyll cell in high-N plants. Furthermore, K supply resulted in the upregulation of gene expression for GhGS2 in leaves, while simultaneously downregulating the expression of GhNADH-GOGAT, GhGDH1 and GhGDH3 genes in high-N roots. The enzyme activities of nitrite reductase and glutamine synthetase increased and glutamate dehydrogenase decreased, but the concentration of NO3- and soluble protein exhibited a significant increase and free amino acid decreased in the shoots subsequent to K supply.

Climatic seasonality challenges the stability of microbial-driven deep soil carbon accumulation across China

Microbial residues contribute to the long-term stabilization of carbon in the entire soil profile, helping to regulate the climate of the planet; however, how sensitive these residues are to climatic seasonality remains virtually unknown, especially for deep soils across environmental gradients. Here, we investigated the changes of microbial residues along soil profiles (0-100 cm) from 44 typical ecosystems with a wide range of climates (~3100 km transects across China). Our results showed that microbial residues account for a larger portion of soil carbon in deeper (60-100 cm) vs. shallower (0-30 and 30-60 cm) soils. Moreover, we find that climate especially challenges the accumulation of microbial residues in deep soils, while soil properties and climate share their roles in controlling the residue accumulation in surface soils. Climatic seasonality, including positive correlations with summer precipitation and maximum monthly precipitation, as well as negative correlations with temperature annual range, are important factors explaining microbial residue accumulation in deep soils across China. In particular, summer precipitation is the key regulator of microbial-driven carbon stability in deep soils, which has 37.2% of relative independent effects on deep-soil microbial residue accumulation. Our work provides novel insights into the importance of climatic seasonality in driving the stabilization of microbial residues in deep soils, challenging the idea that deep soils as long-term carbon reservoirs can buffer climate change.

Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.e., natural/semi-natural ecosystems) shared similar levels of multiple soil contaminants (metal(loid)s, pesticides, microplastics, and antibiotic resistance genes) across the globe. We reveal that human influence explained many forms of soil contamination worldwide. Socio-economic factors were integral to explaining the occurrence of soil contaminants worldwide. We further show that increased levels of multiple soil contaminants were linked with changes in microbial traits including genes associated with environmental stress resistance, nutrient cycling, and pathogenesis. Taken together, our work demonstrates that human-driven soil contamination in nearby natural areas mirrors that in urban greenspaces globally, and highlights that soil contaminants have the potential to cause dire consequences for ecosystem sustainability and human wellbeing.

Local temperature increases reduce soil microbial residues and carbon stocks

Warming is known to reduce soil carbon (C) stocks by promoting microbial respiration, which is associated with the decomposition of microbial residue carbon (MRC). However, the relative contribution of MRC to soil organic carbon (SOC) across temperature gradients is poorly understood. Here, we investigated the contribution of MRC to SOC along two independent elevation gradients of our model system (i.e., the Tibetan Plateau and Shennongjia Mountain in China). Our results showed that local temperature increases were negatively correlated with MRC and SOC. Further analyses revealed that rising temperature reduced SOC via decreasing MRC, which helps to explain future reductions in SOC under climate warming. Our findings demonstrate that climate warming has the potential to reduce C sequestration by increasing the decomposition of MRC, exacerbating the positive feedback between rising temperature and CO₂ efflux. Our study also considered the influence of multiple environmental factors such as soil pH and moisture, which were more important in controlling SOC than microbial traits such as microbial life-style strategies and metabolic efficiency. Together, our work suggests an important mechanism underlying long-term soil C sequestration, which has important implications for the microbial-mediated C process in the face of global climate change.

[Clinical report of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia]

Objective: To investigate the reduction effect of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia. Methods: The therapeutic effects of 40 patients with arytenoid dislocation(AD)treated by closed reduction in the single center from January 2020 to September 2021 were retrospectively analyzed, including 21 males and 19 females, median age 48 years. The etiology, symptoms, preoperative evaluation methods, reduction mode, reduction times, and the recovery of arytenoid cartilage movement and sound after reduction were evaluated and analyzed. Results: All patients had obvious hoarseness and breath sound before treatment. Under stroboscopic laryngoscope or electronic nasopharyngoscope, different degrees of vocal cord movement disorder and poor glottic closure can be seen. There were 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation. The etiology of dislocation of cricoarytenoid joint: 25 cases (62.5%) of tracheal intubation under general anesthesia were the most common causes, was as follows by laryngeal trauma, gastroscopy, cough, vomiting and so on. Among them, 28 cases of reduction were initially diagnosed in our department, and 12 cases were diagnosed later after failure of reduction treatment. Of the 40 patients, 6 underwent reduction 24 hours after dislocation; 18 cases from 3 days to 1 month; 7 cases from 1 to 3 months; 6 cases were reset in 3~6 months; Over 6 months in 3 cases. After one reduction, 10 cases (10/40, 25%) recovered normal pronunciation, 14 cases (14/40, 35%) recovered normal pronunciation after two reduction, 10 cases (10/40, 25%) recovered normal pronunciation after three times, 2 cases (2/40, 5%) recovered normal pronunciation after four times, and 1 case (2.5%) recovered normal pronunciation after five times. Thin slice CT scan of larynx and cricoarytenoid joint reconstruction showed the types of AD: subluxation in 37 cases (92.5%) and total dislocation in 3 cases; 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation; 29 cases (72.5%) had posterior dislocation and 11 cases (27.5%) had anterior dislocation. All patients were treated by intravenous anesthesia with arytenoid cartilage clamped by cricoarytenoid joint reduction forceps under visual laryngoscope. The curative effect was evaluated by stroboscopic laryngoscope and/or voice analysis at 1-2 weeks after operation. The vocal cord movement returned to normal and the pronunciation was good in 37 cases (92.5%). Conclusions: Hoding cricoarytenoid joint reduction with the vision laryngoscope under intravenous anesthesia is easy to operate and the reduction effect is more stable. It is a effective method for AD.

Microbial assemblies associated with temperature sensitivity of soil respiration along an altitudinal gradient

Identifying the drivers of the response of soil microbial respiration to warming is integral to accurately forecasting the carbon-climate feedbacks in terrestrial ecosystems. Microorganisms are the fundamental drivers of soil microbial respiration and its response to warming; however, the specific microbial communities and properties involved in the process remain largely undetermined. Here, we identified the associations between microbial community and temperature sensitivity (Q₁₀) of soil microbial respiration in alpine forests along an altitudinal gradient (from 2974 to 3558 m) from the climate-sensitive Tibetan Plateau. Our results showed that changes in microbial community composition accounted for more variations of Q₁₀ values than a wide range of other factors, including soil pH, moisture, substrate quantity and quality, microbial biomass, diversity and enzyme activities. Specifically, co-occurring microbial assemblies (i.e., ecological clusters or modules) targeting labile carbon consumption were negatively correlated with Q₁₀ of soil microbial respiration, whereas microbial assemblies associated with recalcitrant carbon decomposition were positively correlated with Q₁₀ of soil microbial respiration. Furthermore, there were progressive shifts of microbial assemblies from labile to recalcitrant carbon consumption along the altitudinal gradient, supporting relatively high Q₁₀ values in high-altitude regions. Our results provide new insights into the link between changes in major microbial assemblies with different trophic strategies and Q₁₀ of soil microbial respiration along an altitudinal gradient, highlighting that warming could have stronger effects on microbially-mediated soil organic matter decomposition in high-altitude regions than previously thought.

[Characteristics and Assessment of Heavy Metal Contamination in Soils of Industrial Regions in the Yangtze River Economic Belt]

The Yangtze River Economic Belt is one of the areas with rapid economic development in China, although the intensive industrial activities have aggravated the emissions of soil pollutants in this area. Industrial activities are important sources of soil heavy metal contamination; however, the spatial distribution and main emission sources of soil heavy metal contamination in industrial regions of the economic belt remain unclear. Here, we collected data on the concentrations of eight heavy metals (Cd, Cr, Cu, Pb, Ni, Hg, As, and Zn) in the surface soils of 193 industrial regions covering 11 provinces and cities of the Yangtze River Economic Belt from China National Knowledge Infrastructure (CNKI), Web of Science, and other public databases. On this basis, we analyzed the spatial distribution characteristics of heavy metals and the contamination characteristics of typical industries. The results showed that the heavy metal contamination in agricultural land was more serious than that in industrial land. A total of 58.49%, 39.53%, and 22.64% of the agricultural land, respectively, contained levels of Cd, Zn, and Pb that exceeded the screening values of the Soil Environmental Quality Control Standard for Soil Pollution Risk of Agricultural Land (GB 15618-2018). The results of geo-accumulation index analysis showed that the contamination degree of the eight heavy metals was in the order of Cd (2.52)>Hg (1.17)>Pb (1.00)>Zn (0.90)>Cu (0.72)>As (0.02)>Cr (-0.40)>Ni(-0.48). As for the spatial distribution, Hg, Cd, As, Cu, Pb, and Zn were the main pollutants in the upstream and middle reaches of the industrial regions, whereas As, Cd, and Hg were the main pollutants in the downstream industrial regions. Different types of industry caused different types of contamination. Mining industries caused the most serious soil contamination, the main pollutants of which were Hg and Cd, followed by Cu, Pb, and Zn. Furthermore, metal processing industries mainly caused Cd and Pb contamination. The surrounding soils of chemical industries were contamination-free or only slightly polluted by the eight heavy metals, whereas petroleum processing industries mainly caused Cd contamination. Our study provides important theoretical basis for the future prevention and control of soil heavy metal contamination in industrial regions of the Yangtze River Economic Belt.

Soil microbial trait-based strategies drive metabolic efficiency along an altitude gradient

Trait-based approaches provide a candidate framework for linking soil microbial community to ecosystem processes, yet how the trade-offs in different microbial traits regulate the community-level metabolic efficiency remains unknown. Herein we assessed the roles of the microbial taxa with particular trait strategies in mediating soil microbial metabolic efficiency along an altitude gradient on the Tibetan Plateau. Results showed that soil microbial metabolic efficiency declined with increasing altitude, as indicated by the increasing metabolic quotient (microbial respiration per unit biomass, qCO2) and decreasing carbon use efficiency (CUE). Both qCO2 and CUE were predominantly predicted by microbial physiological and taxonomic attributes after considering key environmental factors including soil pH, substrate quantity and quality. Specifically, the reduced metabolic efficiency was associated with higher investment into nutrient (particularly for phosphorus) acquisitions via enzymes. Furthermore, we identified key microbial assemblies selected by harsh environments (low substrate quality and temperature) as important predictors of metabolic efficiency. These results suggest that particular microbial assemblies adapted to nutrient limited and cold habitats, but at the expense of lower metabolic efficient at higher altitude. Our findings provide a candidate mechanism underlying community-level metabolic efficiency, which has important implications for microbial-mediated processes such as carbon dynamics under global climate changes.

[Measurement and research status of stable hydrogen isotopes in tree-ring lignin methoxyl groups]

The primary hydrogen (H) source for all organic compounds in the biosphere is from water, and then participates in biogeochemical cycles through photosynthesis and plant physiological metabolism. As a new proxy of paleoclimate and paleoenvironment, stable hydrogen isotope ratios in wood lignin methoxyl groups (δ²H_LM) show great advantages in the studies of paleoclimatic change and have been used to reconstruct precipitation stable hydrogen isotope ratios and paleoclimate signals in many regions. Based on the lignin application mechanism and analysis method of δ²H_LM, we evaluated the stability and effectiveness of δ²H_LM-measurement method from lignin content and lignin monomer composition, and expounded the tree lignin methoxyl groups' stable isotope proxies of current research outcomes. In the middle latitudes, the tree-ring δ²H_LM had great potential in recording temperature signals and precipitation stable hydrogen isotope ratios. However, the study of tree-ring δ²H_LM was still in its infancy as evidenced by following reasons: 1) The study area was limited to the middle latitude of the northern hemisphere, and the study subjects were limited to conifer species; 2) To compensate for the limitation of hydrogen isotopic records of nitrocellulose, high resolution tree-ring δ²H_LM would be studied; 3) The potential of tree-ring δ²H_LM utilization in plant physiology and forest ecology remained to be exploited.

[Intra-annual high resolution stable isotope records of tree ring: Methods, progress and prospects]

Stable isotope ratios of tree ring can effectively record climate and environmental changes during tree growth and the physiological responses of trees to such changes. Intra-annual high resolution stable isotope ratios of tree ring can provide more detailed climatic and environmental information, reveal the physiological and ecological response mechanism of trees to seasonal climatic variation, and thus with great potential in the study of paleoclimate and global change ecology. Based on the intra-annual high resolution stable isotope ratios related literature since 1990, we reviewed the research progress of intra-annual high resolution tree ring stable isotope records in the aspects of sample stripping method, chemical extraction method of α-cellulose and application, and further proposed the potential and future development direction of intra-annual high resolution tree ring stable isotope records.

High resolution front-side visualization of charge stored in EEPROM with scanning nonlinear dielectric microscopy (SNDM)

By exposing floating gates of EEPROM memory cells with frontside sample preparation, scanning nonlinear dielectric microscopy (SNDM) succeeded in reading back the data stored in the memory cells with a 250 nm node size. At an optimized voltage bias of AC = 3 V and DC = 1 V, a clear signal contrast between programmed and erased cells is obtained. The high resolution SNDM signal reveals the details of bowling-pin shape structure of memory cells, providing high confidence in data assignment during forensic applications. Such high resolution also makes SNDM a promising technique for newer generation devices with smaller node size.

Global diversity and ecological drivers of lichenised soil fungi

Lichens play crucial roles in sustaining the functioning of terrestrial ecosystems; however, the diversity and ecological factors associated with lichenised soil fungi remain poorly understood. To address this knowledge gap, we used a global field survey including information on fungal sequences of topsoils from 235 terrestrial ecosystems. We identified 880 lichenised fungal phylotypes across nine biomes ranging from deserts to tropical forests. The diversity and proportion of lichenised soil fungi peaked in shrublands and dry grasslands. Aridity index, plant cover and soil pH were the most important factors associated with the distribution of lichenised soil fungi. Furthermore, we identified Endocarpon, Verrucaria and Rinodina as some of the most dominant lichenised genera across the globe, and they had similar environmental preferences to the lichenised fungal community. In addition, precipitation seasonality and mean diurnal temperature range were also important in predicting the proportion of these dominant genera. Using this information, we were able to create the first global maps of the richness and the proportion of dominant genera of lichenised fungi. This work provides new insight into the global distribution and ecological preferences of lichenised soil fungi, and supports their dominance in drylands across the globe.

[Responses of soil phosphorus fractions and microorganisms to nitrogen application in a subtropical Phyllostachys pubescen forest]

Phosphorus (P) is an important nutrient for plant and microbial growth. Soil P availabi-lity is poor in subtropical areas. Long-term heavy nitrogen (N) deposition might further reduce P availability. The experiment was performed in a Phyllostachys pubescens forest in Daiyun Mountain. The effects of N application on soil basic physical and chemical properties, soil P fractions, microbial biomass, and acid phosphomonoesterase activity were analyzed after three years of N application. The results showed that N application significantly increased NO₃^--N content and thus soil N availability, while it significantly reduced the percentage of decomposable organic P to total P, with the ratio of carbon (C) to organic P being over 200. The soil microbial biomass C, microbial biomass P, acid phosphomonoesterase, and the ratio of microbial biomass N to microbial biomass P and microbial biomass C to microbial biomass P were increased as the N application rate increased. There was a significant negative correlation between the percentage of decomposable organic P to total P and microbial biomass P. Consequently, N application enhanced soil P limitation and increased microbial P demand.

Predictive value of thymidylate synthase expression in gastric cancer: a systematic review with meta-analysis

PURPOSE

The relationship between thymidylate synthase (TS) expression and outcomes in gastric cancer (GC) patients remains controversial, although most studies reported poor survival and reduced response to fluoropyrimidine were related to high TS in tumors. We carried out a systematic review of the literature with meta-analysis to estimate the predictive value of TS expression from published studies.

METHODS

We identified 24 studies analysing the outcome data in gastric cancer stratified by TS expression. Effect measures of outcome were hazard ratios (HRs) for overall survival (OS) and event-free survival (EFS), or the odds ratio (OR) for overall response rate (ORR). HRs and ORs from these eligible studies were pooled using random-effects meta- analysis.

RESULTS

Fifteen studies investigated outcomes in a total of 844 patients with advanced GC, and nine studies investigated outcomes in a total of 1,235 patients with localized GC undergoing adjuvant therapy. Meta- analysis of estimates showed high TS expression was significantly associated with poor OS in the advanced setting (HR: 1.43, 95%CI: 1.08 - 1.90), and poor EFS in the adjuvant setting (HR: 1.53, 95%CI: 1.01 - 2.32). Subgroup analysis demonstrated TS expression to have even greater value in predicting OS, EFS and ORR in advanced GC patients treated with fluoropyrimidine monotherapy (HR for OS: 2.32, 95%CI: 1.53 - 3.50; HR for EFS: 1.76, 95%CI: 1.19 - 2.60; OR for ORR: 0.32, 95%CI: 0.11 - 0.95).

CONCLUSION

High levels of TS expression were associated with a poorer OS for advanced GC patients compared with low levels. In the adjuvant setting, high TS expression was also associated with a worse EFS. Additional studies with consistent methodology are needed to define the precise predictive value of TS.

Gender-specific associations between MICA-STR and nasopharyngeal carcinoma in a southern Chinese Han population

Previous studies have identified several HLA-B specificities that are associated with nasopharyngeal carcinoma (NPC) in populations of Chinese descent, in particular HLA-B35, -B38, -B46, and -B58. Perhaps except for HLA-B46, other associations cannot be simply accounted for by the linkage disequilibrium between HLA-A and B loci. The human major histocompatibility complex (MHC) class I chain-related gene A (MICA) maps 46 kb centromeric to HLA-B and is highly polymorphic; it encodes a stress-inducible protein which functions as a ligand for the NKG2D/DAP10 complex to activate natural killer (NK) cells, gammadelta T cells, and CD8(+) T cells. We postulated MICA gene as a susceptibility factor for nasopharyngeal carcinoma, an Epstein-Barr virus-associated malignancy. In this study, 218 unrelated patients newly diagnosed with NPC and 196 randomly selected healthy controls from southern China mainland were analyzed for the short tandem repeat polymorphism of exon 5 of MICA gene (MICA-STR) and MICA gene deletion, using fluorescent polymerase chain reaction-gene scanning (PCR/size-sequencing) and polymerase chain reaction-sequence-specific priming (PCR/SSP) technology. MICA*A9 was present at significantly increased frequency in the patient group (P (C)=0.0001002, OR=2.528, 95% CI=1.636-3.907), whereas the frequency of MICA*A5.1 was significantly decreased (P (C)=0.006, OR=0.594, 95% CI=0.437-0.806). Gender-based stratification revealed a significant increase of MICA*A9 frequency (P (C)=0.000072, OR=3.255, 95% CI=1.855-5.709) and a significant decrease of MICA*A5.1 frequency (P (C)=0.000737, OR=0.486, 95% CI=0.337-0.702) in male patients with NPC (N=166), compared with male normal controls (N=120). A significant interaction between MICA*A9 and gender was observed ([see text]=41.58, P=0.0001). Statistics also revealed heterogeneity of effects among MICA*A5.1/MICA*A9-bearing phenotypes and a dose-dependent effect of MICA*A5.1 and MICA*A9 on NPC risk in male subgroup. This constitutes the first demonstration of a gender-specific association between MICA-STR polymorphism and NPC, which could largely be attributable to the underlying gender-related mechanisms that modulate MICA gene expression. The results provide strong supporting evidence suggesting that MICA*A9 may be a genetic risk factor for NPC in male individuals in this population. The potential interaction between MICA and other non-HLA host factors and environmental exposures remains to be further studied.

Delivery of formoterol from a novel multi-dose inhaler Airmax

Using a proprietary technology known as the X-ACT system--Active-metering, Cyclone-separator Technology, a novel multi-dose inhaler (Airmax) was developed to provide accurate and consistent dosing and a high-fine particle fraction ofthe drug. Formoterol, present as a blend with lactose monohydrate was delivered from Airmax to obtain a nominal formoterol dose of 6 or 12 microg. The devices were tested using a five-stage liquid impinger and a unit dose sampling apparatus, operated under conditions specified in European Pharmacopoeia (2000). Fine-particle dose (FPD) was defined as the dose of the aerosolized drug particles with an aerodynamic diameter < 5 microm and fine particle fraction (FPF) was the ratio of FPD to the total recovered dose. Dose per actuation was found to be 97.0+/-11.5% label claim (LC) or 5.8+/-0.7 microg (n = 140), and 100+/-9.4% LC or 12+/-1.1 microg (n=440), for the 6 and 12 microg strengths, respectively. The mass median aerodynamic diameter was 2.4+/-0.1 microm (n = 14), the geometric standard deviation 2.1+/-0.1 (n = 14), and FPF 44.4+/-24% (n= 14) for both strengths. Thus, the combination of active metering and cyclone separator produces highly consistent doses of formoterol that have a large respirable fraction.

Delivery of salbutamol and of budesonide from a novel multi-dose inhaler Airmax

A novel multi-dose inhaler has been developed to closely approach the characteristics of an "ideal" inhaler. The new device, Airmax, uses proprietary technologies known as the X-ACT system to provide accurate and consistent dosing and excellent lung deposition--even at low inspiratory flow rates--combined with ease of use by the patient. Dose delivery was close to label claim, with relative standard deviation of typically around 5% for through-life emitted mass and around 10% for dose per actuation. At a flow rate (60-70 l/min), which corresponds to 4 kPa pressure drop across the device, the mean fine particle (<5 microm) dose (FPD) from 100, 200 and 400 microg strength budesonide Airmax was around 46, 98 and 244 microg, respectively. The mean FPD from 100 microg strength salbutamol Airmax was approximately 50 microg at the same flow rate. At 30 l/min, the delivered dose from Airmax is over 85% label claim with fine particle fraction of over 35%. Performance was unaffected by shaking or orientation, provided the device was not used completely upside down, and priming was not required. There was no change in dose content uniformity and aerodynamic particle-size distribution after the devices have been stored unwrapped at 30 degrees C/60% RH up to 24 months. Airmax is robust, portable and intuitive to use.

Lactose as a carrier in dry powder formulations: the influence of surface characteristics on drug delivery

The aim of the study was to investigate the interdependence of carrier particle size, surface treatment of the carrier, and inclusion of fines on the drug delivery from dry power inhaler formulations. Two size fractions (< 63 and 63-90 microm) of alpha-lactose monohydrate were subjected to treatment with 95% (v/v) ethanol to introduce small asperities or cavities onto the otherwise smooth surface without substantially changing the particle shape. After blending with albuterol sulfate [ALB; volume median diameter (VMD), 1.9 microm; geometric standard deviation (GSD), 1.5], the solvent-treated lactose produced a fine particle fraction (FPF; < 6.18 microm) and dispersibility of the drug that was significantly (ANOVA p < 0.01) lower than that which resulted from formulations containing untreated lactose of a similar size fraction, after aerosolization at 60 L min(-1) via a Rotahaler. The two size fractions of the treated lactose resulted in similar deposition profiles of ALB. The effects of such surface asperities or cavities of lactose were offset by introducing a small amount (5% w/w) of smaller-sized lactose (5-10 microm) to the powder formulations. The fine lactose increased the FPF and dispersibility of ALB to such a level that all lactose batches, regardless of particle size or whether solvent treated, produced a similar fraction of aerosolized ALB. The inclusion of recrystallized needle lactose (5-15 microm) was superior to micronized lactose in improving the aerosolization of ALB. The findings of this study indicate that the presence and characteristics of the finer fraction of lactose carrier particles dominate over the particle size and surface smoothness of the carrier particles in determining dispersion and deaggregation of drugs from dry powder formulations for inhalation.

Effects of molecular weight of polyvinylpyrrolidone on the glass transition and crystallization of co-lyophilized sucrose

The purpose of the present study was to investigate the effects of molecular weight (MW) of polyvinylpyrrolidone (PVP) on glass transition and crystallization of sucrose. Thus, sucrose was co-lyophilized with 2.5 and 5.0% w/w PVP of different molecular weights, which were characterized using gel permeation chromatography. Freeze drying was carried out for 48 h at a shelf temperature of -40 degrees C and a pressure of about 36 Pa. The samples were then dried in a vacuum oven at 24 degrees C for 12 h before drying for a further 12 h at 40 degrees C. Differential scanning calorimetry (DSC) was employed to measure the glass transition temperature (Tg), dynamic crystallization temperature (Tc) and isothermal crystallization induction time (tc) at 85 degrees C of sucrose. Isothermal water vapour sorption of each sample was also measured at different relative humidities. Tg values of sucrose varied from 48.3+/-0.8 degrees C for freeze-dried (FD) sucrose alone to 58.8+/-0.8 degrees C for the mixture containing 5.0% PVP of nominal MW 300 K. PVP increased sucrose T(g) significantly (ANOVA P<0.05). Although there was no significant difference (P>0.05) in Tg of the mixtures containing 2.5% w/w PVP of different MW, samples with 5.0% PVP of MW 300 K produced a significantly higher (P<0.05) Tg than the other mixtures. All mixtures were shown to possess higher (P<0.01) Tc than FD sucrose alone, which exhibited a T(c) of approximately 85 degrees C. PVP of MW 300 K consistently induced a significantly (P<0.05) higher Tc of sucrose than PVP of smaller MW. Increasing PVP concentration from 2.5 to 5.0% also resulted in a substantial increase in sucrose Tc. Using isothermal water vapour absorption, sucrose tc was found to increase up to over 10 times when it was co-lyophilized with 2.5% PVP, the actual value of tc being dependent upon the MW of the PVP. For example, PVP of MW 300 K resulted in a sucrose tc at 85 degrees C (89.1-95.6 min), which was approximately seven times higher than that of 2.5% PVP of MW 24 or 40 K. A longer tc of sucrose was also observed for mixtures containing PVP of MW 300 K than when sucrose was mixed with PVP of smaller MW. Thus the effect of PVP on sucrose Tg, Tc and tc was found to be dependent upon MW. PVP of higher MW was more efficient in inhibiting sucrose crystallization and by stabilizing glassy structures of the sugar, these polymers may improve the stability of co-lyophilized proteins and peptides.

The use of different sugars as fine and coarse carriers for aerosolised salbutamol sulphate

The aim of this study was to investigate the dispersion and deaggregation of a model drug, salbutamol sulphate (SS), using lactose, mannitol or sorbitol as coarse and fine carriers. Binary and tertiary formulations containing micronised salbutamol sulphate (SS) and sieved (63-90 microm) coarse sugar crystals or salbutamol sulphate (SS) with a mixture of coarse and fine sugar particles were prepared. Factorial design was employed to investigate the effects of three variables, i.e. the chemical entity of the coarse sugar carrier, the chemical entity of the fine sugar and the concentration of fine sugar, on the dispersion and deaggregation of salbutamol sulphate after aerosolisation at 60 l/min via a Rotahaler(R) into a twin stage liquid impinger (TSI). The binary formulations containing the different sugar entities produced differences in the fine (<6.4 microm) particle fraction (FPF) of SS in a decreasing order of mannitol >sorbitol >lactose, but failed to produce efficient dispersion of SS since the FPF was <10%. Adding fine sugar particles and increasing their concentration to the binary mixtures generally resulted in an increase in the FPF of salbutamol sulphate. The chemical nature of the fine carriers was found to play a less important role in determining respirable fraction of the drug than the coarse carriers. In conclusion, other sugars such as mannitol or sorbitol, besides lactose, may be employed as coarse and/or fine carriers for incorporation into dry powder aerosol formulations to increase FPF.

The effects of carrier size and morphology on the dispersion of salbutamol sulphate after aerosolization at different flow rates

We have investigated the interdependence of various factors (particle size, surface smoothness, carrier particle shape, inhalation flow rate) on the deposition of a model drug (salbutamol sulphate) after aerosolization from a model inhaler device (Rotahaler). Different batches of alpha-lactose monohydrate were prepared to have different particle size, particle shape and surface smoothness. Each batch of lactose was then mixed separately with salbutamol sulphate in a ratio of 67.5 : 1 (w/w), under similar conditions. Drug deposition from each formulation was investigated using a 4-stage liquid impinger after aerosolization at 28.3, 60.0 and 96.0 L min(-1) via a Rotahaler. At a flow rate of 28.3 L min(-1), a large portion of drug particles was not emitted from the inhaler, the % emission varying from 29.6% to 66.6% for all formulations investigated. Drug emission tended to increase with particle size of the carrier whilst fine particle fraction, fine particle dose and dispersibility appeared to increase with decreasing particle size but increasing elongation ratio of the carrier particles. Increasing the flow rate to 60.0 L min(-1) was shown to increase drug emission since > 75% total dose was found to be emitted from the inhaler. Again, smaller or more elongated lactose particles resulted in a higher fine particle dose or fine particle fraction of salbutamol sulphate than the coarser carrier, although they produced a similar (analysis of variance P > 0.05) drug emission. Increasing the flow rate to 96.0 L min(-1) did not increase drug emission. Increasing the flow rate resulted in an increase in the fine particle fraction and fine particle dose of salbutamol sulphate from all formulations. The flow rate of the airstream appeared to play the most important role, followed by particle size and elongation ratio of the carrier particles, with the surface smoothness relatively less significant in determining the deposition of salbutamol sulphate from the Rotahaler.

Crystallization of lactose from carbopol gels

PURPOSE

To crystallize lactose under static conditions with a view to preparing crystals of well-defined morphology.

METHODS

et-Lactose monohydrate was crystallized from neutralized Carbopol 934 gels. When the majority of crystals had grown to maturity, the gels were acidified using diluted hydrochloric acid and the crystals were harvested by filtration or centrifugation and washed with ethanol-water mixtures.

RESULTS

Crystals prepared from the gel had a consistently narrower size distribution than control crystals, prepared from solution under constant stirring. If crystallization was effected in the gel without sedimentation of the crystals, then the resultant crystals had smooth surfaces without visually detectable surface roughness or asperities viewed by optical microscopy. The crystals from Carbopol gels also exhibited the uniform shape of an elongated tomahawk regardless of the crystallization conditions, in contrast to crystallization under constant stirring, where the crystal shape of lactose changed with crystallization conditions especially as a function of the initial concentration of lactose. All batches of lactose crystals prepared from Carbopol gels existed as alpha-lactose monohydrate, which showed better flowability than the controls of a similar particle size.

CONCLUSIONS

Crystallization from Carbopol gel produces lactose crystals of uniform size, regular shape, smooth surface, and improved flowability.

The influence of crystallization conditions on the morphology of lactose intended for use as a carrier for dry powder aerosols

Lactose has been widely used as a carrier for inhalation aerosols. The carrier morphology is believed to affect the delivery of the drug. The aim of this study was to investigate the effects of crystallization conditions on the morphology of alpha-lactose monohydrate intended for use as the carrier for dry powder aerosols. The crystallization of lactose was carried out from aqueous solutions at different supersaturations, temperatures, different stages of crystallization and in the presence of different water-miscible organic solvents. The majority of lactose crystals were found to be either tomahawk-shaped or pyramidal after crystallization at an initial lactose concentration between 33-43% w/w, but these became prismatic if the lactose concentration was increased to 50% w/w. A further increase in the lactose concentration to 60% w/w led to the preparation of elongated cuboidal crystals. Higher initial lactose concentrations tended to result in the crystallization of more elongated particles. Crystallization at 40 degrees C was shown to prepare lactose crystals with a more regular shape and a smoother surface than those crystallized at 0 degrees C. Lactose particles generated during the later stage of crystallization were found to be more regular in shape with a smoother surface than those prepared in the earlier stage. The addition of 10% (v/v) methanol or ethanol or acetone to the mother liquor increased the growth rate of lactose particles whereas addition of propanol or glycerine inhibited the rate of crystal growth. Lactose crystals prepared in the presence of glycerine were more regularly shaped with a smoother surface than those prepared in the presence of ethanol or acetone. All the resultant crystals were shown to comprise alpha-lactose monohydrate. Lactose crystals could be prepared with a precisely defined morphology by means of carefully controlling the crystallization conditions.

The influence of carrier morphology on drug delivery by dry powder inhalers

Alpha-lactose monohydrate was prepared to have different morphological features but with similar particle size. The crystal shape and surface smoothness of lactose were quantified by a number of shape descriptors and these were supported qualitatively by the visual examination of scanning electron (SE) micrographs of the crystals. All batches of lactose were subjected to a similar history of processing before blending separately with micronised salbutamol sulphate (SS) in a ratio of 67.5:1, w/w, using similar procedures. In vitro deposition of SS from these formulations was investigated after aerosolisation of the formulations at 60 l min(-1) via the Rotahaler and the Cyclohaler into a twin stage liquid impinger. The formulations prepared using the different batches of lactose produced different deposition profiles of SS. The fine particle (< 6.4 microm) fraction (FPF) of aerosolised SS varied from 12.6 +/- 2.4 to 25.6 +/- 1.5% after aerosolisation from the Cyclohaler whilst it changed from 15.0 +/- 2.2 to 24.4 +/- 0.8% after aerosolisation from the Rotahaler. The fine particle dose (FPD) and dispersibility of SS followed a similar trend to the change in the FPF of the drug. No significant difference (ANOVA P > 0.05) was observed for the deposition profiles of SS after aerosolisation from the Rotahaler and the Cyclohaler. The FPF and dispersibility of SS increased with either the surface smoothness (P < 0.01) or elongation ratio (P < 0.01) of lactose crystals. The t-ratio values of FPF and dispersibility of SS generated by changes in the surface smoothness were similar to those resulting from changes in elongation ratio. Increasing either the surface smoothness or the elongation ratio of lactose crystals will increase the potentially respirable fraction of SS from dry powder formulations for inhalation.

The influence of lactose carrier on the content homogeneity and dispersibility of beclomethasone dipropionate from dry powder aerosols

Dry powder formulations for inhalation usually comprise a mixture of coarse lactose (CL), employed as a carrier, and micronized drug. It was the aim of this study to determine the effects of fine lactose (FL), blended as a tertiary component on the mixing homogeneity and dispersibility of a model hydrophobic drug, beclomethasone dipropionate (BDP). BDP particles (volume median diameter (VMD) 4.6 microm) existed mainly as agglomerates, the majority of which were not dispersed into primary particles after aerosolization at a high shear force (4.7 psi). The resultant particle size distribution of BDP was multi-modal with VMD varying between 4.7 and 30.2 microm. Ternary interactive mixtures were prepared to consist of CL, FL and BDP with a fixed ratio of lactose to BDP of 67.5:1 w/w, but two concentrations of FL, i.e. 2.5 and 5%, w/w. The mixing was carried out using different sequences of adding the three components for two mixing times (15 and 60 min). Binary mixtures composed of CL and BDP were prepared for both mixing times as the controls, and these exhibited a coefficient of variation (COV) in BDP content <= 5%. Addition of FL to the binary formulations greatly reduced the content uniformity of BDP if the final powder were prepared by first mixing CL with FL before mixing with the drug (COV>20%, after mixing for 15 min). However, the mixtures, prepared using other mixing sequences, had a similar uniformity of BDP content to the binary mixtures. All ternary mixtures containing 2.5% FL consistently produced a significantly higher (ANOVA P<0.01) fine particle fraction (FPF, 3.1--6.1%) and fine particle dose (FPD, 13.6--30.1 microg) of BDP than the binary mixtures (FPF, 0.3-0.4%; FPD, 1.6-2.1 microg) after aerosolization at 60 l min(-1) via a Rotahaler into a twin stage liquid impinger. The mixing sequences exerted a significant (P<0.05) effect on the dispersion and deaggregation of BDP from the formulations prepared using a mixing time of 15 min but such an effect disappeared when the mixing time was lengthened to 60 min. The dispersibility of BDP was always higher from the ternary mixtures than from the binary mixtures. BDP delivery from dry powder inhalers was improved markedly by adding FL to the formulation, without substantial reduction in the content uniformity of the drug.

The use of different grades of lactose as a carrier for aerosolised salbutamol sulphate

Five different grades of lactose namely, anhydrous lactose, medium lactose, regular lactose, lactose crystals and foremost lactose were fractionated under similar conditions to obtain a size range of 63-90 microm and were characterised using laser diffraction and time-of-flight particle sizing techniques, scanning electron microscopy, optical microscopy image analysis, thermal gravimetric analysis and differential scanning calorimetry. Each of these lactose fractions were then blended separately with micronised salbutamol sulphate in a ratio of 67.5:1 (w/w). The mixing uniformity and percentage recovery of salbutamol sulphate in the powder blends were analysed using a validated HPLC method. The deposition profiles of the drug were determined using a 5-stage liquid impinger after aerosolisation at 60 l min(-1) via a Rotahaler. Despite the identical processing conditions, the lactose fractions were shown to differ in particle size, size distribution and concentrations of fine particles. The particles from each fraction also exhibited different surface textures and dissimilar DSC thermograms. However, all the blends of the lactose with salbutamol sulphate were found to have a relatively high uniformity of salbutamol sulphate content, as suggested by a coefficient of variation of less than 3.2%. Anhydrous and medium lactose produced a more efficient delivery of salbutamol sulphate when aerosolised from the Rotahaler in comparison to other grades of lactose. For example, the fine particle fraction (FPF) and fine particle dose (FPD) of drug from formulations containing anhydrous lactose were 13.4+/-4.2% and 57.3+/-17.6 microg, respectively, which were approximately two times higher than the respective values of the formulation containing regular lactose. Medium lactose resulted in drug FPF (7. 9+/-2.7%) and FPD (32.4+/-11.8 microg), which were significantly (ANOVA P<0.05) higher than the same parameters obtained using lactose crystals, foremost lactose and regular lactose. More efficient drug delivery from anhydrous lactose may be partly attributed to the relatively higher concentration of fine lactose in this grade of carrier, although it showed a rougher surface than the other grades of lactose. However, the relatively high FPF of the drug from medium lactose may have been due to the relatively small mean particle size and smooth surface of the particles. Therefore, the source and grade of lactose may have a substantial effect on drug delivery from dry powder inhaler formulations and care should be taken in establishing appropriate quality control parameters when selecting an appropriate grade of carrier.

Effects of particle size and adding sequence of fine lactose on the deposition of salbutamol sulphate from a dry powder formulation

Ternary mixtures composed of coarse lactose (CL) (90.8 microm), salbutamol sulphate (SS) (5.8 microm) and either micronised lactose (ML) (5 microm) or intermediate sized lactose (IML) (15.9 microm) in a ratio of 66.5:1:1 w/w were prepared using different mixing sequences of the various components. In addition, a binary mixture composed of CL and SS (67.5:1 w/w) was also prepared as the control. The in vitro deposition of SS was measured using a twin stage impinger after aerosolisation at 60 and 90 l min-1 via a Rotahaler. The aerodynamic particle size distribution of both the aerosolised SS and lactose was further analysed using an Andersen cascade impactor at 60 l min-1. All ternary mixtures produced a significantly higher (analysis of variance, P<0.01) fine particle fraction (FPF) and fine particle dose (FPD) of SS than the control after aerosolisation at either 60 or 90 l min-1. Formulations containing the ML produced significantly (P<0.05) higher FPF and FPD of SS than those containing the IML at both aerosolisation flow rates. Different mixing sequences were also shown to result in different deposition profiles of both SS and lactose after aerosolisation of the ternary mixtures containing ML at 60 l min-1. The formulation prepared by first blending ML with CL before mixing with SS produced a higher FPF and FPD of SS but a lower FPF of lactose than the same formulation in terms of composition but prepared using different mixing orders of the three components. In contrast, the formulations containing IML produced a similar deposition profile to SS, regardless of the mixing sequences, and so did the formulations containing ML aerosolised at 90 l min-1. These results suggest that the effect of mixing sequences on drug deposition may become more prominent at lower aerosolisation flow rates and by reducing the size of any added fine lactose.

[Evaluation of detecting 9 tumor markers in serum for diagnosis of primary liver cancer]

Nine tumor markers in serum including alpha-fetoprotein (AFP), r-glutamyltranspeptidase (GGT), lactate dehydrogenase (LDH), alpha 1-antitrypsin (alpha 1-AT), total sialic acid (TSA), ferritin (Ft), ceruloplasmin (CP), LDH isoenzymes and GGT isoenzymes were used for differential diagnosis of primary liver cancer. Of 5 measurement data tested by statistics, CP and TSA were close to normal distribution (P > 0.1), GGT, LDH and alpha 1-AT showed skewness distribution or to be close to normal distribution with in transformation (P > 0.1). The results indicated that the determination of the cut-off value should depend on the statistical distribution of data. Analysis of single and dual-combination tests as well as triple analysis with sequential progressive screening had been performed to evaluate the predictive value of clinical diagnosis, i.e. the sensitivity, the specificity and the correct diagnosis efficiency. Three predictive values of a single test were lower than what clinical diagnosis raqvest. The dual-combination tests had higher specificity but a lower sensitivity. For triple analysis with sequential progressive screening among the liver cancer group (n = 23), the related disease group (n = 44) and the healthy individuals group (n = 40), the correct diagnosis efficiency was 95%, 97.3% and 100%, respectively. This suggests that the method described here has potential value in clinical practice.

[Relationship between HBcAg in the liver and mechanisms of chronic type B hepatitis HBVM in serum]

We detected the presence and distribution of HBcAg in the liver by immunohistochemistry (ABC method) and the presence of HBV-DNA in serum (spot hybridization) and anti-HBe in serum (ELISA) from 59 cases of hepatitis B hospitalized in our hospital, including 47 cases of CAH, 5 cases of CPH, and 7 cases of subacute fulminant hepatitis. 1. HBcAg in the liver was detected in 25 out of 47 cases (53%) of CAH, in 2 out of 5 cases of CPH and in 4 out of 7 cases of subacute fulminant hepatitis. The total percentage was 53% (31/59). 2. There was no positive correlation between HBV replication activity and liver disease activity (P greater than 0.05). Our results did not support the hypothesis that suggests a direct cytopathic effect of HBV. Oppositely, the fact was that the presence, the amount and the patterns of HBcAg in the liver, and the presence of HBV-DNA in serum were predominant in mild CAH compared with those in severe CAH, predominant in CAH without cirrhosis compared with those in CAH with cirrhosis. There was a tendency of inverse correlation between HBV replication activity and liver disease activity. The results above were in line with the concept that HBcAg expressed on the surface of infected hepatocytes may be relevant target for T lymphocyte cytotoxicity. The results have suggested that an immune response to HBV is present, leading to the destruction of most infected cells. 3. There was a positive correlation between HBV-DNA in serum and HBcAg in the liver (P less than 0.005), indicating that HBV-DNA in serum can represent HBV replication.(ABSTRACT TRUNCATED AT 250 WORDS)