医用聚丙烯酰胺水凝胶红外吸收光谱化学结构分析

目的　通过对医用聚丙烯酰胺水凝胶(Amazingel)化学结构分析，C、H、O、N元素之间的分子链、交联、支链离解等结构的变化。方法　采用红外吸收光谱KBR压片法。结果　KBR压片法红外吸收光谱图中有酰胺基、仲酰胺、亚甲基的特征峰与标准聚丙烯酰胺图谱基本相同。结论　该材料属高分子三维网状结构的聚合物，没有发现有链和支链分子间的离解，其化学结构稳定。     

医用聚丙烯酰胺水凝胶红外吸收光谱化学结构分析

目的 通过对医用聚丙烯酰胺水凝胶（Amazingel)化学结构分析,C、H、O、N元素之间的分子链、交联、支链离解等结构的变化。方法 采用红外吸收光谱KBR压片法。结果 KDR压片法红外吸光谱图中有酰胺基、仲酰胺、亚甲基的特征峰与标准聚丙烯胺图谱基本相同,结论 该材料属高分子三维网状结构的聚合物。没有发现有链和支链分子间的离解,其化学结构稳定。     

玉米淀粉的挤压研究──淀粉在挤压过程中降解机理的研究（Ⅱ＿b）

利用ＳｅｐｈａｄｅｘＧ－２００凝胶过滤层折，碘吸附值，碘络合物吸收光谱，Ｘ－射线衍射光谱等方法对挤压淀粉进行了研究。结果表明，玉米淀粉在挤压过程中，其直链级分未发生显著变化，支链级分的降解位置位于其分子内部，挤压施加于淀粉聚合物的剪应力是挤压淀粉中直链淀粉脂肪络合物的Ｖ型结构向Ｅ型结构转换的根本原因。依据淀粉的聚集态结构，从理论上阐述了淀粉在挤压过程中降解的力化学过程，并提出淀粉降解可能为自由基过程的机理。     

玉米淀粉的挤压研究——淀粉在挤压过程中降解机理的研究(Ⅱ_a)

采用SephadexG-50葡聚糖凝胶层析、酶法分析、红外光谱以及统计分析等方法对挤压淀粉进行了研究。研究表明,玉米淀粉在挤压过程中降解处于力化学降解初期,经过挤压支链淀粉级分中的a链和b链,在G-50色谱中的分布未发生显著性变化,挤压导致支链淀粉级分的支点发生裂解。     

聚丙烯酰胺水凝胶取出术中多发性乳腺纤维腺瘤一例分析

聚丙烯酰胺水凝胶(简称"水凝胶")为胶状物质,是由聚丙烯酰胺聚合体与水组成,其生物凝胶的化学结构稳定,长期留存于体内不易被降解,但这种聚合物分解后的单体在体内能产生聚丙烯酰胺单体的毒性症状[1-3],包括神经毒性及可能的生殖毒性、致癌性[4-6],已被国际癌症研究机构分类为2A组,即"可能人类致癌物".     

唇增厚:手术选择和组织学检查--聚丙烯酰胺水凝胶应用部分

1 外科技术 聚丙烯酰胺水凝胶(PAAG)在80年代后期以诺亚米德(Royamid)的命名应用到美容外科.聚丙烯酰胺水凝胶是呈胶冻样、透明样的物质,它是由95%的水和5%的亲水性生物相容性交链的聚丙烯酰胺所组成.     

灰树花菌丝体抗肿瘤糖肽GFPS1b结构的研究

以体外抑制肿瘤细胞增殖的活性作为筛选导向，从灰树花深层发酵培养菌丝体中提取、分离纯化得到一酸性糖酞GFPS1b．HPGPC法测得其重均相对分子质量为21000．蛋白质质量分数16．60％，糖质量分数为81．32％。利用化学方法（单糖组成分析、部分酸水解、甲基化分析）和仪器方法（GC、GC—MS、红外吸收光谱、核磁共振）分析GFPS1b的糖链结构，结果表明其单糖组成主要有G1c、Ga1、Ara和少量的糖醛酸，其糖链主链由两个α-D—G1c（1→3）、α-D—Ga1（1→4）、α-D—G1c（1→3，6）和α-D—Ga1（1→6）组成的，其中葡萄糖基的6位发生取代，取代侧链主要为α-L—Ara-（1—4）-α-D—Glc（1→。可以认为GFPS1b为一新糖肽。     

中国医师协会美容与整形医师分会全国医用聚丙烯酰胺水凝胶（奥美定）专家研讨会会议纪要

为了切实认真地贯彻科学发展观,客观、求实、科学、严谨地研讨和论证“医用聚丙烯酰胺水凝胶(奥美定)”产品的安全性等问题,经中国医师协会领导同意,本分会于2005年10月30日在北京召开了“全国医用聚丙烯酰胺水凝胶(奥美定)专家研讨会”。参加这次研讨会的有来自全国的化学专家     

松口蘑菌丝体糖蛋白MP的性质及其结构

通过聚丙烯酰胺凝胶电泳、红外、紫外扫描、气相色谱、氨基酸组成、β 消去反应等方法研究松口蘑菌丝体糖蛋白MP的结构性质,结果表明,该糖蛋白的相对分子质量为57000,红外扫描有典型的多糖吸收峰,糖苷键为α型;单糖组成为葡萄糖和木糖,摩尔比(r)为34∶1,紫外扫描有蛋白质吸收峰,蛋白质量分数为75.5%,多糖为24.5%,多糖与蛋白质为O 糖肽键连接.     

甘薯水溶性糖蛋白的分离纯化及结构初探

采用二乙基氨基纤维素DEAE-52和葡聚糖凝胶G100柱层析法,从甘薯中分离纯化甘薯糖蛋白,并对其结构进行了初步探讨.研究结果表明,糖蛋白纯品呈白色,易溶于水;蛋白质质量分数为61.2%,通过SDS-聚丙烯酰胺凝胶电泳对糖蛋白进行纯度鉴定,结果显示只有一条谱带.气相色谱分析表明甘薯糖蛋白中糖链部分含有鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖;红外光谱和β-消去反应表明:甘薯糖蛋白中含有α-糖苷键,糖苷键类型主要为吡喃型;糖与蛋白的肽链之间的连接点类型是O-糖肽键.     

The depth-dependent anisotropy of articular cartilage by Fourier-transform infrared imaging (FTIRI)

OBJECTIVE: To study the anisotropic characteristics of individual histological zones in articular cartilage using Fourier-transform infrared imaging (FTIRI) at 6.25microm pixel resolution. METHOD: A canine humeral cartilage-bone block was paraffin-embedded and microtomed into 6microm sections. Each of the five sections was infrared (IR)-imaged 26 times with identical acquisition parameters, for a 5-10 degrees increment of a wire grid polarizer introduced before the detector in 0-180 degrees angular space. Following the IR imaging experiments, the same tissue sections were also imaged by polarized light microscopy (PLM). RESULTS: The IR absorption components of cartilage (amide I, amide II, amide III, and sugar) exhibit distinctly different anisotropies, which vary differently as a function of the tissue depth. A new type of image, "the absorbance anisotropy map", was constructed for each major component, which shows that (1) the absorbance of the amide components in most parts of the tissue is anisotropic, (2) the anisotropic behavior in the radial and the superficial zones of the tissue is opposite, (3) the absorption profile of amide I is inverse to those of amide II and amide III, and (4) the IR absorption of the sugar component is almost isotropic. The anisotropic variations of the amide components were fitted to an empirical equation. CONCLUSIONS: The IR anisotropy map is a powerful tool to monitor the individual chemical components in articular cartilage. The ability to examine the same tissue section using both FTIRI and PLM offers the possibility of correlating the tissue's morphology with chemical distribution.     

Secondary structure of soybean trypsin inhibitor (Kunitz): a study by infrared spectroscopy

The infrared spectrum (amide I' region) of Kunitz soybean trypsin inhibitor (SBTI) was obtained in D2O solution and resolved into Gaussian components. A prominent broad band centered at 1643 cm-1 is shown on the unresolved spectrum, which is usually assigned to N-deuterated peptide groups in an unordered structure, since SBTI is known to be devoid of alpha-helix by CD and X-ray crystallographic studies. In addition, shoulders are evident at 1632 cm-1 and 1676 cm-1, which correspond probably to the v(pi, O) and v(O, pi) components assigned to an antiparallel-chain beta-pleated sheet structure. Parameters (maximum absorptivity, wavenumber at the maximum of the band, and half-width of the band at half-height) for the four Gaussian component bands (in which the amide I' band was resolved) are given. A crude estimation of 4% is obtained for antiparallel beta-sheet in SBTI, i.e., this protein would be practically devoid of such a beta-structure. Notwithstanding the fact that this result is apparently in agreement with the far-UV CD spectrum (data reported in the literature), the predominant conformation class found in SBTI has been demonstrated to be approximate beta-sheet structures, with a small amount of regular sheet (Sweet et al., (1974) Biochemistry 13: 4212-4228).     

Fourier-transform infrared anisotropy in cross and parallel sections of tendon and articular cartilage

Background

Fourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.

Methods

Thin sections (6 μm thick) were obtained from three different surfaces of the canine tissue blocks and imaged at 6.25 μm pixel resolution. For each section, infrared imaging experiments were repeated thirteen times with the identical parameters except a 15° increment of the analyzer's angle in the 0° – 180° angular space. The anisotropies of amide I and amide II components were studied in order to probe the orientation of the collagen fibrils at different tissue surfaces.

Results

For tendon, the anisotropy of amide I and amide II components in parallel sections is comparable to that of regular sections; and tendon's cross sections show distinct, but weak anisotropic behavior for both the amide components. For articular cartilage, parallel sections in the superficial zone have the expected infrared anisotropy that is consistent with that of regular sections. The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.

Conclusion

From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.     

Biomimetic mineralization of charged collagen matrices: in vitro and in vivo study

Polyanionic collagen matrix prepared by hydrolysis side chain amides of asparagine and glutamine was mineralized in vivo, without inflammatory response, biodegradation, or resorption, with calcium phosphate deposited in close resemblance to the D-periodicity of collagen fibrils assembly. In vitro results with the same material produced mineralized collagen fibers with a similar morphology and chemical characteristics, suggesting that amide hydrolysis may have introduced into this matrix, signs for the controlled mineralization of collagen fiber. TEM indicated that amide hydrolysis occurred near the OVERLAP and GAP zones, as suggested by the significant reduction in inter-band distances in these regions. The lack of an inflammatory response associated to the similar mineralization pattern observed in vivo and in vitro suggests not only the biomimetic behavior of polyanionic collagen matrix, but also its potential uses as scaffold for bone tissue reconstruction. Based on these results, a model for the in vitro mineralization was also proposed.     

On the increasing fragility of human teeth with age: a deep-UV resonance Raman study.

UV resonance Raman spectroscopy (UVRRS) using 244-nm excitation was used to study the impact of aging on human dentin. The intensity of a spectroscopic feature from the peptide bonds in the collagen increases with tissue age, similar to a finding reported previously for human cortical bone. INTRODUCTION: The structural changes that lead to compromised mechanical properties with age in dentin and bone are under intense study. However, in situ analyses of the content and distribution of the mineral phase are more highly developed at present than equivalent probes of the organic phase. MATERIALS AND METHODS: Thirty-five human molars were divided into three groups: young/normal (23.3 +/- 3.8 years); aged/transparent (74.3 +/- 6.0 years), which had become transparent because of filling of the tubule lumens with mineral deposits; and aged/nontransparent (73.3 +/- 5.7 years). Control experiments were performed by demineralizing normal dentin. RESULTS: Spectral features caused by both the amide backbone and resonance-enhanced side-chain vibrations were observed. This finding contrasts with reported Raman spectra of proteins in solution excited with similar UV wavelengths, where side chain vibrations, but not strong amide features, are observed. The strong intensity of the amide features observed from dentin is attributed to broadening of the resonance profile for the amide pi --> pi* transition caused by the environment of the collagen molecules in dentin. With increasing age, the height of one specific amide vibration (amide I) becomes significantly higher when comparing teeth from donors with an average age of 23 years to those of 73 years (p < 0.001). This trend of increasing amide I peak height with age is similar to that previously reported for human cortical bone. The amide I feature also increased in dentin that had been demineralized and dehydrated. CONCLUSIONS: The similar trend of increasing amide I peak height with age in the UVRR spectra of both teeth and bone is surprising, given that only bone undergoes remodeling. However, by considering those observations together with this study of demineralized/dehydrated dentin and our prior work on dentin dehydrated with polar solvents, a consistent relationship between changes in the UVRR spectra and the collagen environment in the tissue can be developed.     

复方支链氨基酸注射液对结直肠癌根治术后患者的营养支持作用

目的评价复方支链氨基酸注射液对结直肠癌根治术后患者的营养支持作用。方法将50例结直肠癌根治术后患者随机分为研究组和对照组,每组25例。研究组使用10．3%复方支链氨基酸注射液；对照组使用10．4%复方氨基酸注射液。比较两组患者血清总蛋白、白蛋白、前白蛋白、转铁蛋白的浓度和氮平衡及术后并发症的发生情况。结果术后第8天,研究组与对照组营养状况比较：白蛋白浓度[(36．12±3．16)g/L与(30．61±3．55)g/L]比较,P＜0．05；前白蛋白浓度[(237．10±37．29)mg/L与(191．73±27．60)mg/L]比较,P＜0．05；转铁蛋白浓度[(2．18±1．34)g/L与(1．71±0．84)g/L]比较,P＜0．05；差异均有统计学意义。研究组氮平衡从术后第5天始优于对照组,为9．91±6．53；而对照组第6天仍为负氮平衡(-9．73±11．21)；两组比较P＜0．05；差异有统计学意义。研究组切口感染及愈合不良发生率仅占8．3%,而对照组为38．1%,两组比较P＜0．05；差异有统计学意义。结论结直肠癌术后使用富含支链氨基酸的注射液可减少蛋白分解,尽快改善负氮平衡,并促进伤口愈合。     

The effect of enriched branched chain amino acid solution with hypocaloric TPN on acute phase protein, plasma amino acid profile metabolism in postoperative children]

From 1988 to 1990, 27 postoperative children with aganglionic megacolon were studied prospectively. They were randomly divided into three groups according to the postoperative fluid supply: group A, dextrose, group B, balanced amino acid solution (24% branch chain amino acid); and group C, solution enriched with branched chain amino acid (45% BCAA). The serum acute phase protein and plasma amino acid profile were observed. Nitrogen balance was monitored daily in all groups during the perioperative period. The data showed that prealbumin, transferrin rose more rapidly in group C than in group A and group B. The solution of 45% BCAA was found to be superior to balanced 24% BCAA in normalizing the disorder of plasma amino acid spectrum on the 3rd day and 7th day after operation. Urea nitrogen excretion was reduced in group C more rapidly than in group A and group B on the 4th day after operation. Using solution enriched branched chain amino acid with hypocaloric TPN in postoperative children can achieve an effective nitrogen sparing effect.     

Raman spectroscopy of calcified tissue

Laser Raman spectra of ox tibia and of reconstituted rat tail tendon have been obtained and have been compared with the infrared spectra of calcified tissue and collagen. The most intense Raman bands in the calcified tissue originate from the symmetric phosphate modes; however, several of the backbone and side chain modes of collagen are also apparent. There is some evidence that both proline and phenylalamine in the collagen contribute to the spectrum. The Raman spectrum of reconstituted, collagen was difficult to separate from the fluorescence background. Only six distinct bands could be obtained, divided between peptide and sidechain modes. Differences between reconstituted and calcified collagen spectra may originate from partial denaturation of the former in the laser beam. Other differences seem to be genuine chemical manifestations.     

Bilirubin calculi crushing by laser irradiation at a molecular oscillating region wavelength based on infrared absorption spectrum analysis using a free-electron laser: an experimental study

We investigated a new laser technique of crushing bilirubin calculi, our aim being to crush calculi in isolation using a minimally invasive procedure. Infrared absorption spectrum analysis of the bilirubin calculi was conducted, revealing maximum absorption spectrum at a wavelength of the C=O stretching vibration of ester binding that exists within the molecular structure of bilirubin calcium. As an experiment to crush calculi using the free-electron laser, we set the laser at the effective irradiation wavelength of ester binding, and conducted noncontact irradiation of the bilirubin calculi. The calculi began to slowly ablate until the irradiated site had been completely obliterated after 20 s of irradiation. Moreover, absorption spectrum analysis of the irradiated site, from a comparison of absorption peak ratios, revealed that absorption peak intensities decreased over time at the absorption wavelength of ester binding. These findings suggest that irradiation of molecular oscillating region wavelengths peculiar to calculi based on infrared absorption spectrum analysis results in the gradual crushing of calculi in isolation by breaking down their molecular structure. Received: December 7, 1999 / Accepted: November 20, 2000