Human myeloma light chains with increased molecular weight: high frequency among lambda chains

The discovery of a human myeloma protein comprising a kappa L-chain with an increased mol. wt of 30,000) (Bouvet et. al., 1980) prompted investigations on the incidence of such heavier L-chains among other human myeloma proteins. In 105 samples examined, 34 were found to have L-chains heavier than normal (23,000-24,000), ranging from 25,000 up to 31,000, and five of lighter mol. wt (21,000-22,000). These mol. wt abnormalities were detected by electrophoresis in sodium dodecyl sulfate 10% polyacrylamide gels (SDS-PAGE) after reduction with 2-mercaptoethanol. The mol. wt of three of the heavier kappa or lambda chains was also estimated by filtration through a Sephadex G100 column and by sedimentation equilibrium. All three methods indicated a mol. wt increase of about 15-25% as compared with the usual mol. wt. The distribution of the high mol. wt chains among all L-chains examined was found to be 11 out of 62 kappa chains (17.7%) and 23 out of 43 lambda chains (53%) (P less than 0.001). A preferential association of such L-chains with H-chains producing multiple bands in SDS-PAGE (P less than 0.01) and an association between multiple L-chain and multiple H-chain band (P less than 0.05) were also observed. In contrast, no abnormal L-chain was found in immunoglobulins from normal subjects. Spontaneous degradation of the normal H-chains sometimes yielded fragments of 30,000 mol. wt. These fragments were easily distinguishable from abnormal L-chains. The nature of extra mol. wt in heavy L-chains was investigated for the presence of carbohydrate moiety. Four large and three normal size L-chains were examined for amino-sugar and sialic acid content. A small amount (one residue per molecule) of amino-sugar was detected only in two normal and two heavy L-chains, whereas sialic acid was only found in the heaviest (27,000-30,000) L-chains (Lh) and in small percentage (one or two residues per molecule). Total sugar estimation in one Lh chain indicated a proportion not exceeding three or four residues per L-chain (mol. wt 1,000) and this is insufficient to explain the 15-25% (3,600-6,000) mol. wt increase. It is therefore possible that, at least in some heavy myeloma L-chains, an additional peptide is expressed. Whatever the nature of the increase it would be of interest to elucidate whether this is a marker of malignant process or of an intermediate step of normal Ig synthesis.     

Differential vulnerability of microtubule components in cerebral ischemia

Summary Differential vulnerability of the major components of microtubules was examined in ischemic gerbil brains by a light microscopic, immunohisto-chemical method using monoclonal antibodies for microtubule-associated protein (MAP) 1A and MAP2, polyclonal antibody for MAP1 and 2 as well as monoclonal antibody for -tubulin. Progressive cerebral ischemia during unilateral carotid occlusion for 5, 15 and 120 min and reperfusion for 3, 12 and 48 h following bilateral carotid occlusion for 10 min were studied. Ischemic lesions in the subiculum-CA1 region were visualized by all antibodies after ischemia for 5 min but the antibody for -tubulin was less sensitive. The antibody for -tubulin was also less sensitive than antibodies for MAPs for detection of early postischemic lesions. Differential sensitivity was also observed in the cerebral cortex and other brain regions. Microtubules in myelinated axons were more stable than those in dendrites. The observed loss of immunohistochemical reactivities for MAPs and -tubulin may have been caused by activation of calcium-dependent proteolytic enzymes such as calpains. The discrepancy between MAPs and -tubulin could be due to differences in affinities or topographic distributions of these proteins within microtubules.Supported by the grant NS-06663 from the National Institutes of Health, U.S. Public Health Service     

Nonlinear Binding of Valproic Acid (VPA) and E-Δ2-Valproic Acid to Rat Plasma Proteins

The binding characteristics of valproic acid (VPA) and its pharmacologically active monounsaturated metabolite, E-²-VPA, to rat plasma proteins were compared. The plasma free fraction was determined by a rapid equilibrium procedure, which minimizes the interfering effects of nonesterified fatty acids liberated by in vitro lipolysis. Nonlinear binding behavior was observed with both compounds over their respective pharmacologic concentration range. Multiple binding-site models were invoked to explain the binding isotherm. The 2-unsaturated compound has a much higher affinity for the rat plasma proteins (mainly albumin) than its saturated precursor. The equilibrium association constants for the high- and intermediate-affinity sites were more than an order of magnitude higher with E-²-VPA than with VPA (10⁴–10⁶ versus 10³ M ^–1). This difference in binding affinity was also reflected by a lower plasma free fraction for E-²-VPA compared with VPA (<<10 versus >20% at total concentrations of less than 100 µg/ml). A more pronounced dose- and concentration-dependent variation in the distribution and clearance kinetics is predicted for the 2-unsaturated analogue compared to VPA. Also, the structural dependency in plasma protein binding observed with these branched-chain fatty acids may provide insights into the mechanism of interaction between fatty acyl molecules and albumin.     

人钠/二羧基转运蛋白1在肾组织的表达变化及其与肾结石发病的关系

目的研究肾组织钠/二羧基转运蛋白1(hNaDC1)表达变化与肾结石发病的的关系.方法85例肾结石患者分为、尿枸橼酸正常结石组和低枸橼酸尿结石组.并设50例对照为非结石患者.采用RT-PCR及Northem印迹法检测其中部分肾结石患者肾组织的hNaDC1mRNA水平;免疫组化检测hNaDCl蛋白表达的变化;常规生化方法测定血、尿枸橼酸、草酸等生化指标.结果低枸橼酸尿结石组结石复发率(36.1%),显著高于尿枸橼酸正常结石组(16.3%,P＜0.01).hNaDC1mRNA在正常肾组织中有表达,分布于近端肾小管刷状缘;低枸橼酸尿结石患者hNaDC1mRNA/18sRNA比值(0.65±0.21)显著高于对照组(0.36±0.11,P＜0.01);而尿枸橼酸正常结石患者(0.4±0.13)与对照组比较差异无显著意义(P＞0.05);低枸橼酸尿结石组hNaDC1蛋白表达也显著高于对照组及尿枸橼酸正常结石组(P＜0.01),而后两组间差异无显著意义(P＞0.05).低枸橼酸尿结石组尿pH值、尿钠水平显著低于尿枸橼酸正常结石组和对照组;尿钙、尿草酸水平均显著高于对照组,与尿枸橼酸正常结石组无显著差异.结论肾组织hNaDC1表达上调可能是低枸橼酸尿的重要原因,与肾结石的形成和复发存在某种内在联系.     

复合rhBMP2的异种骨的研制及成骨活性

目的：研制新型具有诱导成骨活性的异种骨植骨材料。方法：在重组合异种骨（RBX）基础上,以基因重组人BMP2（rhBMP2）取代从牛皮质骨中提取的牛BMP,与去抗原牛松质骨载体（BCB）复合,制成复合rhBMP2的异种骨（rhBMP2/BCB）,并采用小鼠股部肌袋模型,通过组织学、骨计量学方法检测rhBMP2/BCB的诱导成骨活性。结果：实验组（rhBMP2/BCB组）术后7d在小鼠肌袋可诱导软骨生成,14d形成纺织骨,21d改建成板状骨并形成大量骨髓;对照组（BCB组）于术后各时间点均未见有软骨成骨形成。实验组的碱性磷酸酶活性和钙含量均高于对照组,有非常显性差异（P＜0．01）。结论：rhBMP2/BCB具有较好的骨诱导能力,是一种较理想的植骨材料。     

实验性自身免疫性内耳病耳蜗热休克蛋白70的表达

目的　探讨自身免疫性内耳病模型动物耳蜗热休克蛋白的表达。方法　利用同种异体内耳抗原免疫豚鼠 ,以建立自身免疫性内耳病 (autoimmuneinnereardisease ,AIED)动物模型 ,并应用免疫组织化学及原位杂位技术 ,研究热休克蛋白 (heatshockprotein ,hsp) 70在正常对照组及AIED模型动物实验组耳蜗中的表达情况。结果　对照组豚鼠螺旋神经节细胞中存在hsp70样蛋白基础表达 ;实验组 2 8耳中 10耳 (35 7% )听阈提高≥ 10dB ;此组动物螺旋神经节细胞和血管纹、螺旋韧带hsp70及其mRNA表达明显增强。结论　以粗制膜迷路抗原免疫豚鼠 ,听阈提高动物hsp70在螺旋神经节细胞和血管纹、螺旋韧带合成增加。     

Nondomain biopolymers: Flexible molecular strategies to acquire biological functions

A long-standing assumption in molecular biology posits that the conservation of protein and nucleic acid sequences emphasizes the functional significance of biomolecules. These conserved sequences fold into distinct secondary and tertiary structures, enable highly specific molecular interactions, and regulate complex yet organized molecular processes within living cells. However, recent evidence suggests that biomolecules can also function through primary sequence regions that lack conservation across species or gene families. These regions typically do not form rigid structures, and their inherent flexibility is critical for their functional roles. This review examines the emerging roles and molecular mechanisms of “nondomain biomolecules,” whose functions are not easily predicted due to the absence of conserved functional domains. We propose the hypothesis that both domain- and nondomain-type molecules work together to enable flexible and efficient molecular processes within the highly crowded intracellular environment.     

Analysis of Drug/Plasma Protein Interactions by Means of Asymmetrical Flow Field-Flow Fractionation

Purpose. The applicability of Asymmetrical Flow Field-Flow Fractionation (Asymmetrical Flow FFF) as an alternative tool to examine the distribution of a lipophilic drug (N-Benzoyl-staurosporine) within human plasma protein fractions was investigated with respect to high separation speed and loss of material on surfaces due to adsorption. Methods. Field-Flow Fractionation is defined as a group of pseudo-chromatographic separation methods, where compounds are separated under the influence of an externally applied force based on differences in their physicochemical properties. This method was used to separate human plasma in its protein fractions. The drug distribution in the fractions was investigated by monitoring the fractionated eluate for drug content by fluorescence spectroscopy. Results. Human plasma was separated into human serum albumin (HSA), high density lipoprotein (HDL), ₂-macroglobulin and low density lipoprotein (LDL) fractions in less than ten minutes. Calibration of the system and identification of the individual fractions was performed using commercially available protein reference standards. The influence of membrane type and carrier solution composition on the absolute recovery of N-Benzoyl-staurosporine and fluorescein-isothio-cyanate-albumin (FITC-albumin) was found to be quite significant. Both factors were optimized during the course of the investigations. N-Benzoyl-staurosporine was found to be enriched in the fraction containing HSA. Conclusions. If experimental conditions are thoroughly selected and controlled to suppress drug and plasma protein adsorption at the separation membrane, Asymmetrical Flow FFF shows high recoveries and fast separation of human plasma proteins, and can be a reliable tool to characterize drug / plasma protein interactions. For analytical purposes it has the potential to rival established technologies like ultracentrifugation in terms of ease-of-use, precision, and separation time.     

流行性出血热患者早期免疫应答的研究

应用反向被动血凝集抑制试验和血凝集抑制试验检测流行性出血热患者早期血清（７病日内）中病毒核蛋白、膜蛋白抗体。１０３例患者血清,仅核蛋白抗体出现者３３例,病情转径及无变化者３１例（９３．９４％）．而转重者仅２例（６．０６％）,且其血清抗体主要为ＩｇＧ型。仅膜蛋白抗体出现的患者９例,病情转重者８例（８８．８９％）,其抗体主要为ＩｇＭ．核蛋白、膜蛋白抗体均阳性的６１例患者,病情转归介于上述二者之间．提示：核蛋白抗体先出现的患者,病情多转轻,而膜蛋白抗体先出现的患者,病情普遍转重,似与病毒的＂一次性打击＂有关。在仅核蛋白抗体出现的患者中,有２例病情转重,但其抗体球蛋白类型为ＩｇＧ,故尚不能排除本病有＂二次感染＂的可能,这一现象在推行本病预防接种时值得重视,另对进一步探讨本病的发病机理及预测患者的病情转归亦具参考价值。     

Fibrodysplasia ossificans progressiva: Still turning into wood after 300 years?

Fibrodysplasia ossificans progressiva (FOP), a rare autosomal dominant disorder, is characterized by symmetrical congenital skeletal abnormalities and progressive heterotopic ossification of the connective tissues. At present, more than 300 years after the first report by Patin in 1648 in which he described the woman who turned to wood, its pathogenesis remains largely unknown and its therapy is limited to symptom-modifying trials. However, significant progress has been recently made and new data on the molecular organization and regulation of normal and disordered bone induction are likely to lead to a more specific therapy. FOP is believed to be a genetic disorder characterized by a disturbed expression of the endochondral osteogenesis programme, and the remarkable clues from the fly reported by Kaplan et al. [8] in 1990 suggest a gain-of-function mutation in the genetic regulation of bone morphogenetic proteins.