Cross reactivity between IA-2 and phogrin/IA-2β in binding of autoantibodies in IDDM

Summary Patients with insulin-dependent diabetes mellitus (IDDM) possess antibodies to the cytoplasmic domains of two closely related tyrosine phosphatase-like proteins, IA-2 and phogrin, previously detected as 40 kDa and 37 kDa tryptic fragments, respectively. A higher proportion of IDDM patients possess antibodies to IA-2 than to phogrin, and autoimmunity to phogrin might arise through cross-reactivity with the highly homologous IA-2. In this study, we have investigated the major regions of IA-2 recognized by antibodies in IDDM patients and examined the ability of phogrin to block antibody binding to these regions as a measure of cross-reactivity. Analysis of antibody binding to in vitro transcribed and translated polypeptides representing different regions of the cytoplasmic domain of IA-2 identified five different patterns of reactivity with antibodies in IDDM. Protein footprinting analysis, whereby polypeptide fragments generated on protease treatment of immune complexes are studied, indicated considerable heterogeneity in antibody recognition of IA-2, even between sera with similar reactivity to deletion mutants. Blocking studies with recombinant phogrin indicated that IA-2 antibodies recognize epitopes that are both unique to IA-2 and shared with phogrin. The amino-terminal 150 amino acids of the cytoplasmic domain of IA-2 encompass epitopes that are not represented on phogrin, whereas shared epitopes are localized within the carboxy-terminal 220 amino acids. The results demonstrate considerable heterogeneity between IDDM patients in autoantibody recognition of IA-2 in IDDM, whereas antibody recognition of phogrin is restricted in most patients to epitopes also present on IA-2. [Diabetologia (1997) 40: 1327–1333] Received: 4 April 1997 and in revised form: 2 July 1997     

Influence of Osteoarthritis on Serum Marker Levels of Bone Formation and Resorption in Patients with Benign Prostatic Hypertrophy

Background :
The aim of this study was to investigate the influence of osteoarthritis of lumbar vertebrae on serum bone formation and resorption marker levels of patients with benign prostatic hypertrophy (BPH).
Methods :
Serum levels of carboxyterminal propeptide of type I procollagen (PICP), alkaline phosphatase (ALP), carboxyterminaltelopeptide of type I collagen (ICTP), and prostate-specific antigen (PSA) were examined in 40 patients with BPH, and the presence of osteoarthritis at the lumbar vertebrae of the patients was evaluated by plain x-ray-p.
Results :
Findings of osteoarthritis were observed in 23 of the 40 patients (58%), and 10 of the patients had severe osteoarthritis (involving at least 2 lumbar vertebral bodies). The serum levels of PICP, ALP, ICTP, and PSA of the patients without osteoarthritis findings were not different from those of the patients with osteoarthritis or severe osteoarthritis.
Conclusion :
The influence of osteoarthritis on serum bone formation and resorption marker levels of patients with BPH appears to be rather slight, if there is any influence at all.     

Duodenogastric reflux after choledochoduodenostomy

Duodenogastric reflux (DGR) has been implicated in several disease processes. The present study was carried out to document the incidence and evaluate the clinical significance of DGR after choledochoduodenostomy (CDD). A total of 13 patients who had undergone cholecystectomy with a standard side-to-side CDD for choledocholithiasis or chronic pancreatitis were studied by symptom evaluation, scintigraphy, endoscopy, and gastric mucosal histology at least 6 months after surgery. The scintigraphic findings were then compared with those of 10 patients who had undergone cholecystectomy alone. Only two patients (15%) had mild dyspeptic symptoms. The incidence of DGR after CDD was 69% compared to 20% in the cholecystectomy alone group (P < 0.05). In the majority of patients the DGR was only mild to moderate and the severity correlated well with the degree of endoscopic gastritis, but not with the clinical symptoms or histological findings. These results indicate that while CDD is associated with a high incidence of DGR, its occurrence does not produce significant clinical symptoms.     

Can bone metabolism markers be adopted as an alternative to scintigraphic imaging in monitoring bone metastases from breast cancer?

Bone scintigraphy plays a major role in the diagnosis of bone metastases. The clinical utility of new biochemical markers of bone metabolism has recently been investigated in various bone diseases. This study evaluated the role of some bone metabolism markers in comparison with bone scan in the follow-up of breast cancer patients. We studied 149 patients with breast cancer, 33 (22%) of whom had bone metastases. IRMAs were used for the evaluation of blood levels of osteocalcin, bone alkaline phosphatase (BAP), the C-terminal propeptide of type I procollagen and the C-terminal cross-linked telopeptide of type I collagen (ICTP). Multivariate regression analysis showed that menopausal status (P=0.007) and metastatic bone lesions (P=0.001) affected bone marker levels. When considering post-menopausal women, the only subset in which bone metabolism marker behaviour could be reliably investigated, we found a high degree of overlap in marker distribution for scan-positive and scan-negative patients. Discrimination between scan-negative and scan-positive patients based on the above markers, taken singly or jointly, was assessed by means of logistic discriminant analysis. The best discrimination was achieved with BAP, closely followed by ICTP. BAP and ICTP together gave a slight improvement over the use of the two markers separately. However, even in this case the degree of discrimination was poor and its clinical utility was limited. In fact, to achieve a specificity of 95%, the sensitivity of the test was about 20%; conversely, with a sensitivity of 95%, the specificity was below 10%. In conclusion, based on our findings, we believe that blood levels of the investigated markers cannot replace bone scintigraphy in the follow-up of breast cancer patients for the early detection of bone metastases. Received 14 April and in revised form 5 July 1997     

Prognostic significance of cytochemical analysis of leukemic M2 blasts

Cytochemical analysis of leukemic blasts from 46 patients with acute myeloblastic M2 leukemia (according to the FAB classification) was performed before and after cytostatic therapy, and compared with findings obtained in 20 age- and sex-matched control subjects. Cytochemical findings for myeloperoxidase (MPO), Sudan black B, acid phosphatase and alpha-naphthyl-acetate esterase (ANAE) were related to the achievement of the first complete remission (CR),i.e. data were compared after the patients had been divided into CR and non-CR groups. The analysis clearly showed that a high proportion of myeloperoxidase- and, to a lesser extent, Sudan black B-positive blasts before treatment may have constituted a significantly unfavourable prognostic factor.     

Diagnosis of gallbladder perforation in acute acalculous cholecystitis in critically ill patients

In the presence of ascites ultrasound is not appropriate to distinguish between gallbladder perforation and acute acalculous cholecystitis. However, the correct and early diagnosis of gallbladder perforation is important for the treatment and prognosis. We report 4 critically ill patients with ascites. All patients had evidence of gallbladder perforation by ultrasound and underwent cholecystectomy: 2 patients had gallbladder perforation, but 2 had acalculous cholecystitis without perforation. markedly elevated serum alkaline phosphatase was the only discriminating finding indicating gallbladder perforation.     

特发性身材矮小儿童成骨细胞的功能状况

目的通过检测特发性身材矮小(ISS)儿童血清骨碱性磷酸酶(BAP)及骨钙蛋白(OC)水平,探讨其成骨细胞的功能状况。方法ISS组36例及健康对照组儿童50例。ISS组分为青春期前组及青春期组。测各组儿童身高、体质量、体质量指数,采用CHN法评定左侧手、腕部骨化指标,计算骨龄。采用ELISA法测其血清BAP及OC水平。结果青春期前,ISS儿童血清BAP及OC水平为(79.90±25.96)U/Lvs(60.96±18.46)μg/L,健康对照组为(152.17±35.36)U/Lvs(76.16±28.03)μg/L;青春期,ISS儿童血清BAP及OC水平为(108.33±35.20)U/Lvs(63.82±24.81)μg/L,健康对照组为(156.30±35.29)U/Lvs(104.92±28.26)μg/L。青春期前及青春期ISS组血清BAP及OC水平均明显低于健康对照组,存在显著性差异(Pa<0.01)。结论ISS儿童以成骨细胞为中心环节的骨塑造和再造能力均较健康生长发育少年儿童差。     

镉对大鼠肾脏和睾丸毒性的比较

大鼠饮水中给镉12wk后,检测了尿低分子蛋白(LMWP)排出量。尿碱性磷酸酶(ALP)活性,血清睾酮水平,睾丸乳酸脱氢酶同功酶(LDH-X)活性,精子计数和形态,雄鼠生育力,肾,睾丸和附睾组织镉含量,并在光镜和电镜下观察上述组织的病理变化,从生化,形态和功能改变三方面比较了大鼠肾脏和睾丸对镉的敏感性,发现尿LMWP和ALP仅在高剂量组显著增加,而血清睾酮和睾丸LDH-X在中剂量纽和低剂量纽已明显降低,说明镉对睾丸的有害作用可出现在肾脏之前。     

Stable Transfection of Nonosteogenic Cell Lines with Tissue Nonspecific Alkaline Phosphatase Enhances Mineral Deposition Both in the Presence and Absence of β-Glycerophosphate: Possible Role for Alkaline Phosphatase in Pathological Mineralization

It is documented that alkaline phosphatase (AP) plays an important role in bone mineralization. Considering that TN-AP is expressed in periodontal ligament fibroblasts, renal epithelial cells, and vascular endothelial cells, and that TN-AP is both a calcium-/phosphate-binding protein and a phosphohydrolytic enzyme, we hypothesize that membrane-bound AP also plays an important role in the initiation of physiological and pathological mineralizations in tissues other than bone and cartilage. To test this hypothesis, nonosteoblast cell lines, including a fibroblast line, a renal epithelial line, and a capillary endothelial line, were stably transfected to express high levels of rat bone AP on their cell surfaces. These rat bone AP-expressing cells were then cultured on filter membranes in the presence or absence of β-glycerol phosphate. von Kossa staining for calcium phosphate and transmission electron microscopy with electron diffraction analysis for minerals were employed to investigate the effect of membrane AP on extracellular calcium phosphate mineralization. Our results indicated that AP expression on these nonosteoblast-like cell surfaces have induced extracellular hydroxyapatite (HAP) mineralization. Our findings support the concept that membrane-bound AP contributes to extracellular apatitic mineralization by mechanisms that do not necessarily involve its hydrolase activity. They also suggest that AP might be important for the initiation of pathological mineralization in nonosteogenic tissues. Received: 11 January 1996 / Accepted: 31 October 1996     

猪肾碱性磷酸酶的提纯及性质研究

目的：从猪肾中提取碱性磷酸酶(ALP)，并对其能否作为参考品进行研究。方法：从猪肾皮质中分离刷状缘微绒毛膜，用正丁醇溶解膜结合的酶，经硫酸铵沉淀，DEAE-Sephacel、ConA-Sepharose、Sephadex G-200及抗γ-谷酰基转移酶(GGT)免疫亲和层析提纯ALP。结果：提纯的ALP比活达402kU／g蛋白，几乎不含杂酶(未检出ALT、AST、ChE、AMY、CK、LDH，GGT仅含2U／780U ALP)。其对底物4-硝基磷酸酚(4-NPP)的Km值为1．35mmol／L，最适pH值为10．40。结论：提纯的猪肾ALP与人血清中的ALP酶动力学特性非常相似，为进一步研制ALP参考品奠定了基础。