Masson三色染色与HE染色在豚鼠牙齿组织石蜡切片中的比较研究及应用

针对牙齿组织形态学研究的难点,选择适宜固定液,用EDTA-2Na进行脱钙,完成了牙齿组织石蜡切片的制作。通过确定染色程序及各种染料的最佳作用时间,分别利用Masson三色染色法、传统的苏木精和伊红（HE）染色法对牙齿组织切片进行了染色观察。染色结果表明,与HE染色法相比,Masson三色染色更能使牙齿的各主要成分以不同颜色显现出来,色彩对比鲜明,亮丽润眼,为牙齿组织生理及病理组织形态学研究奠定了基础。针对机体中硬组织的相似特性,该试验方法可以在骨骼、软骨等硬组织的形态学研究中参考、改进并推广使用。     

骨质疏松症治疗药物的研究进展

骨质疏松症是以骨量减少、骨的微观结构退化为特征,致使骨的脆性增加并易于发生骨折的一种全身性骨骼疾病,是当前严重危害人类特别是绝经妇女和老人的疾病之一.近年来出现了许多预防和治疗骨质疏松症的药物,极大地推动了骨质疏松症理论基础的完善和临床治疗研究.就该领域的研究进展进行了简要综述.     

Soil organic matter in urban soils: Estimation of elemental carbon by thermal oxidation and characterization of organic matter by solid-state C nuclear magnetic resonance (NMR) spectroscopy

To reduce soil destruction by urban sprawl, land use planning has to promote the use of soils within cities. As soil functions are now protected by law in Germany, urban soil quality has to be evaluated before soil management. We studied contributions from elemental carbon (EC) and soil organic matter (SOM) quality in topsoil horizons at seven sites in Stuttgart, Germany, differing in impurities by technogenic substrates. The most disturbed site was found at a disused railway area while high-density areas, public parks and garden areas showed varying degrees of disturbance by anthropogenic activities. For most soils, compounds derived from plant litter dominated organic matter (OM) quality characterized by nuclear magnetic resonance (NMR) spectroscopy. Although high contents of EC (up to 70% of soil organic carbon) were indicated by thermal oxidation, this was not confirmed by aromatic C intensities in NMR spectra. Only for the highly aromatic railway soil were results for elemental carbon by thermal oxidation and NMR similar. As other technogenic substrates beside EC like plastics may also contribute in the long-term to OM in urban soils, new analytical techniques are therefore required. This knowledge will promote the evaluation of urban soil properties and their sustainable use.     

Measurement of the size distribution of water-filled pores at different matric potentials by stray field nuclear magnetic resonance

The water retention characteristic provides the traditional data set for the derivation of a soil's pore‐size distribution. However, the technique employed to achieve this requires that assumptions be made about the way pores interconnect. We explore an alternative approach based on stray field nuclear magnetic resonance (STRAFI‐NMR) to probe the water‐filled pores of both saturated and unsaturated soils, which does not require information relating to pore connectivity. We report the relative size distributions of water‐occupied pores in saturated and unsaturated samples of two sets of glass beads of known particle size, two sands, and three soils (a silty loam, a sandy loam and a loamy sand), using measurements of the NMR T₁ proton relaxation time of water. The T₁ values are linearly related to pore size and consequently measured T₁ distributions provide a measure of the pore‐size distribution. For both the sands and the glass beads at saturation the T₁ distributions are unimodal, and the samples with small particle sizes show a shift to small T₁ values indicating smaller voids relative to the samples with larger particles. Different matric potentials were used to reveal how the water‐occupied pore‐size distribution changes during drainage. These changes are inconsistent with, and demonstrate the inadequacies of, the commonly employed parallel‐capillary tube model of a soil pore space. We find that not all pores of the same size drain at the same matric potential. Further, we observe that the T₁ distribution is shifted to smaller values beyond the distribution at saturation. This shift is explained by a change in the weighted average of the relaxation rates as the proportion of water in the centre of water‐filled pores decreases. This is evidence for the presence of pendular structures resulting from incomplete drainage of pores. For the soils the results are similar except that at saturation the T₁ distributions are bimodal or asymmetrical, indicative of inter‐aggregate and intra‐aggregate pore spaces. We conclude that the NMR method provides a characterization of the water‐filled pore space which complements that derived from the water retention characteristic and which can provide insight into the way pore connectivity impacts on drainage.     

Linking the B ring hydroxylation pattern of condensed tannins to C, N and P mineralization. A case study using four tannins

Condensed tannins (CTs) are a major component of litter inputs, but little is known about the effects of tannin structural variations on soil biological processes and organic matter development. Four different CTs extracted from balsam fir, western red cedar, kalmia and black spruce were added to Corsican pine litter and subsequently incubated for 16 weeks in order to investigate the effect of the B ring hydroxylation pattern on C, N and P transformations. While for C mineralization the chain length and stereochemistry of the CTs seemed to be a more important parameter, net N and P mineralization rates were clearly reduced compared with non-amended litter. With regard to the B ring hydroxylation, the prodelphinidin (PD) CTs having predominantly three hydroxy groups at the B ring (balsam fir and western red cedar) exhibited significantly lower mineralization rates than the procyanidin (PC) CTs having two OH groups (kalmia and black spruce). The same was true for net nitrification, but this process was only slightly affected by the CTs. Although based on only four CTs, this study indicates that B ring hydroxylation is an important variable determining net N and P mineralization rates. Our results support previous suggestions that PD tannins bind to or react more strongly with soil organic matter. Therefore, more than PC tannins, they reduce the availability of organic N for mineralization as well as their own detectability by standard methods for soil CT.     

Technical note: utilization of sainfoin by grazing steers and a method for predicting daily gain from small-plot grazing data.

Sainfoin (Onobrychis viciaefolia Scop.) is adapted to the calcareous soils of the southern Great Plains and can provide early season forage that does not induce bloating; however, little is known about performance by ruminants grazing sainfoin. Our objective was to determine the effect of plant growth stage and grazing pressures on potential animal production from sainfoin as predicted from energy intake as a multiple of maintenance. Nitrogen-fertilized (100 kg of N/ha) Renumex sainfoin was grown under irrigation on a Pullman clay loam (fine, mixed, thermic Torretic Paleustoll) near Lubbock, TX. Light (L), medium (M), and heavy (H) grazing pressures were applied with steers grazing sainfoin that was at the bud (B), flower (F), and seed shatter (S) stages of growth. The L, M, and H pressures were grazed to remove 50, 75, and 90% of the standing plant height. Across growth stages, L, M, and H grazing pressures averaged 52, 69, and 87% removal of pregrazed herbage mass. Dry matter intake as a percentage of BW of steers averaged 3.9, 2.8, and 1.7 for L, M, and H grazing pressures. Across growth stages, predicted live weight gain for L, M, and H grazing pressures averaged .86, .67, and .03 kg/d. Our findings indicate that the multiple of maintenance method may be useful for evaluating treatments from small-plot grazing experiments.     

Effect of energy intake on the postpartum interval in beef cows and the adequacy of the cow's milk production for calf growth

Lactating Hereford and Hereford X Angus cows, 2 to 6 yr old, and their calves were used in two trials to study the effects of energy intake on the postpartum interval (PPI) and the adequacy of the cow's milk production for calf growth. In trial 1, 23 cows were fed either 120 (high energy, HE) or 100% (adequate energy, AE) of National Research Council energy recommendations. Cow weights, calf weights and milk production were determined 1 wk after calving and every 2 wk until 17 wk postcalving . One-half of the calves received creep feed from the start of the study, whereas the other half did not receive creep feed until their average daily gain was below .23 kg/d. In trail 2, 19 cows were fed energy levels of 100 (AE) or 85% (low energy, LE). Estimated percentage body fat ( EPBF ) was estimated twice during the study; other variables were determined as in trial 1. In trial 1, the HE cows gained more weight (P less than .01) and produced more milk (P less than .01). In trial 2, the AE cows gained more weight (P less than .01) and produced calves 17 kg heavier (P less than .01) at the end of the study than did the LE cows. Milk production was not influenced by energy treatment (P greater than .2). It required 7.5 kg of milk and 2.3 kg of creep feed to produce 1 kg of calf gain in trial 1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Observations on blood coagulation after snakebite in dogs and cats

Blood samples from 13 cases of snakebite, 6 in dogs and 7 in cats, were tested for activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrin/fibrinogen degradation products (FDP). Four cases were tested for fibrinogen concentration. Based on the results of a commercially available ELISA test, 9 cases were caused by tiger snakes (Notechis scutatus) and 1 case by a brown snake (Pseudonaja textilis). Three other cases had clinical signs and increased creatine phosphokinase values which suggested tiger snake envenomation. Although the period post-envenomation varied, results indicated a marked prolongation of the APTT and PT in 5 of 6 dogs. Three of these 5 dogs also had increased FDP values and 3 (of 3 examined) were hypofibrinogenaemic. Clinical manifestations of this coagulopathy were: haematoma formation after venepuncture (3 cases), gingival petechiae (1 case) and hyphaema (1 case). In contrast, there was minimal or no prolongation of the APTT and PT values, and no increase in FDP, in all 7 cats. Furthermore, no cat exhibited clinical signs of a coagulopathy.     

Restricted feeding time and the behaviour of caged laying hens

1. Layers housed as pairs in cages were denied access to food from 07.30 to 15.30 h each day. Analyses of video records of daily activity patterns showed several behaviour changes compared with the patterns shown by similar birds allowed ad libitum (AL) access to food. 2. Birds given restricted access (RA) to food spent more time sitting and cage pecking while unable to feed than those feeding ad libitum during the same period. They also engaged in less agonistic pecking and the lengths of bouts of drinking were reduced during the period of food denial compared with the AL treatment. 3. After the food troughs were uncovered birds on the RA treatment showed fewer bouts of feather pecking but more bouts of drinking than the AL treatment. 4. Improvements previously reported in the efficiency of food utilisation of birds on the RA treatment may have been the result of additional sitting, although other activities requiring energy expenditure were performed. 5. It is concluded that restricting access to food on a time basis has both positive and negative effects on the welfare of caged layers.     

Roughage level and limited maximum intake regimens for feedlot steers.

Hereford steers (n = 280, BW = 371 +/- 29 kg; 40 pens) were used to evaluate two alternatives to ad libitum access to feed and constant roughage levels in finishing diets. The eight treatments were as follows: two treatments in which intake was limited to a multiple of the maintenance (MM) energy requirement (2.1, 2.3, 2.5, and 2.7, [2.7MM] and 2.3, 2.5, 2.7, and 2.9 [2.9MM] times maintenance for wk 1, 2, 3, and 4 and thereafter, respectively) and six roughage regimen and grain source treatments (10% roughage equivalent [RE] fed during the mid- and late-finishing periods [10/10], respectively, 2% RE followed by 10% RE [2/10], and 10% RE followed by 2% RE [10/2] fed with steam-flaked sorghum grain [SFSG] or whole-shelled corn [WSC]). The 2.7MM treatment tended to improve ADG (6%, P = .08) and gain efficiency (4%, P = .15) relative to ad libitum access to feed. The 2.9MM treatment was intermediate. Steers fed WSC diets consumed approximately 12% more DM (9.2 vs 8.2 kg/d) and gained 4% more (1.45 vs 1.39 kg/d, P < .05) but had lower gain efficiency (7%, 159 and 170 g/kg, P < .001) than steers fed SFSG diets. For SFSG diets, the 2/10 regimen resulted in similar gains, a 3.6% decrease (P = .10) in DMI, an 8.6% improvement (P < .01) in gain efficiency, and reduced roughage use (40 kg per steer) compared with the 10/10 regimen. With WSC diets, the 2/10 regimen did not (P > .2) affect gain efficiency but did reduce roughage use (48 kg) compared with the 10/10 regimen. The 10/2 regimen did not differ (P > .2) from the 10/10 regimen. Few differences in carcass characteristics were noted among treatments. Roughage use and cost of gain can be reduced by feeding 2% roughage during the mid-finishing period followed by a return to 10% roughage.