Unique Glycoform-Dependent Monoclonal Antibodies for Mouse Mucin 21.

Mucin 21(Muc21)/epiglycanin is expressed on apical surfaces of squamous epithelia and has potentially protective roles, which are thought to be associated with its unique glycoforms, whereas its aberrant glycosylation is implicated in the malignant behaviors of some carcinomas. Despite the importance of glycoforms, we lack tools to detect specific glycoforms of mouse Muc21. In this study, we generated two monoclonal antibodies (mAbs) that recognize different glycoforms of Muc21. We used membrane lysates of Muc21-expressing TA3-Ha cells or Chinese hamster ovary (CHO)-K1 cells transfected with Muc21 as antigens. Specificity testing, utilizing Muc21 glycosylation variant cells, showed that mAb 1A4-1 recognized Muc21 carrying glycans terminated with galactose residues, whereas mAb 18A11 recognized Muc21 carrying sialylated glycans. mAb 1A4-1 stained a majority of mouse mammary carcinoma TA3-Ha cells in vitro and in engrafted tumors in mice, whereas mAb 18A11 recognized only a subpopulation of these. mAb 1A4-1 was useful in immunohistochemically detecting Muc21 in normal squamous epithelia. In conclusion, these mAbs recognize distinct Muc21 epitopes formed by combinations of peptide portions and O-glycans.

Association between bispectral index and age and use of sedative drugs in high spinal anaesthesia.

OBJECTIVES: A prospective, randomized, double-blind study using bispectral index values to objectively quantify the sedative effect of high spinal anaesthesia in patients stratified according to age, and to determine whether sedative drugs are associated with additional adverse respiratory and haemodynamic effects in older patients. METHODS: Patients who were electively scheduled for lower limb or abdominal surgery were recruited and allocated into one of three groups according to their age and whether midazolam and fentanyl were used: younger (20-40 years); and older (61-80 years) with or without midazolam and fentanyl intravenous infusion. RESULTS: The study recruited a total of 90 patients (n = 30 per group). Intraoperative bispectral index values were significantly lower than preoperative values in all groups. Patients in the older age group had significantly lower intraoperative bispectral index values than younger patients. Older patients were significantly more likely to experience respiratory depression (arterial oxyhaemoglobin saturation <90%) than younger patients. CONCLUSIONS: The sedative effect of high spinal anaesthesia is greater in older patients than in younger patients, with an increase in respiratory instability.

Drug overdose due to malfunction of a patient-controlled analgesia machine -A case report-.

Patient-controlled analgesia (PCA) provides excellent pain control and high stability, thereby minimizing the incidence of adverse effects. However, one of our patients experienced respiratory depression and hypotension within 30 minutes of initiation of PCA therapy. We discovered that machine malfunction caused continuous activation of the PCA button, resulting in a drug overdose. The PCA machine was sent to the manufacturer, who found an electrical short in the PCA button. All PCA units of the same make and model were immediately removed from hospitals and replaced with redesigned units without defects in the PCA button. We have used the improved machines without any problems. The purpose of this report is to raise awareness of this type of malfunction in PCA units in order to help prevent adverse events in the future.

Low bone mineral density, but not epidural steroid injection, is associated with fracture in postmenopausal women with low back pain.

BACKGROUND: Therapy with glucocorticoids often results in bone loss and glucocorticoid-induced osteoporosis. However, the relationship between epidural steroid injection (ESI), bone mineral density (BMD), and vertebral fracture remains to be determined. OBJECTIVE: To establish a relationship between ESI, BMD, and vertebral fracture in postmenopausal women with low back pain. STUDY DESIGN: This study was a retrospective, nonblinded, cross-sectional clinical study. SETTING: University-based pain management center. METHODS: We reviewed the medical records of postmenopausal women with low back pain who were treated with ESI. A total of 352 postmenopausal women were divided into 2 groups. Group 1 consisted of patients without fracture and Group 2 consisted of those with fractures. The results of BMD measurements, as well as any fragility fractures, the anatomical site involved, and the treatment administered, were also recorded. BMD was measured in the lumbar spine, femoral neck, and total femur after the treatment. RESULTS: Of the 352 patients, 218 (62%) had no fractures while 134 (38%) sustained a fracture. The age was significantly higher among patients who sustained fractures, and BMD at the lumbar spine, total femur, and femoral neck regions was significantly lower among patients who sustained fractures. In each region, the prevalence of osteoporosis was significantly higher in patients with fracture than in patients without fracture (all P < 0.05). Age, height, and weight were associated with low BMD. However, our study showed no consistent correlation between BMD and the mean number of ESIs, mean total dose of glucocorticoids, or mean duration of ESIs. LIMITATIONS: First, this study is limited by the fact that it was retrospective. Second, the number of cases receiving very frequent, high-dose glucocorticoid injections was very small. CONCLUSIONS: Older age and lower BMD were associated with osteoporotic fracture in postmenopausal women treated for low back pain with ESI. The ESIs were not associated with low BMD or fracture.

Mucin 21 in esophageal squamous epithelia and carcinomas: analysis with glycoform-specific monoclonal antibodies.

Monoclonal antibodies (mAbs) against mucin 21 (MUC21), a human counterpart of mouse epiglycanin/Muc21, were prepared using human embryonic kidney 293 cells transfected with MUC21 as the immunogen. The specificity of these mAbs was examined by flow cytometry, immunoprecipitation and western blotting focusing on the differential glycosylation of MUC21 expressed in variant Chinese hamster ovary (CHO) cells (ldlD cells and Lec2 cells) and CHO-K1 cells. One of these mAbs, heM21D, bound to both the unmodified core polypeptide of MUC21 and MUC21 attached with N-acetylgalactosamine (Tn-MUC21). Six antibodies, including mAb heM21C, bound to MUC21 with Tn, T or sialyl-T epitopes but not the unmodified core polypeptide of MUC21. Esophageal squamous carcinomas and adjacent squamous epithelia were immunohistochemically examined for the binding of these mAbs. MUC21 was expressed in esophageal squamous epithelial cells, and its O-glycan extended forms were observed in the luminal portions of squamous epithelia. As revealed by the binding of mAb heM21D and the absence of reactivity with mAb heM21C, esophageal squamous carcinoma cells produce MUC21 without the attachment of O-glycans. This is the first report to show that there is a change in the glycoform of MUC21 that can be used to differentiate between squamous epithelia and squamous carcinoma of the esophagus. Thus, these antibodies represent a useful tool to characterize squamous epithelial differentiation and carcinogenesis.

Mucin 21/epiglycanin modulates cell adhesion.

The molecular structure of mouse Mucin 21 (Muc21)/epiglycanin is proposed to have 98 tandem repeats of 15 amino acids and three exceptional repeats with 12 or 13 amino acids each, followed by a stem domain, a transmembrane domain, and a cytoplasmic tail. A cDNA of Muc21 having 84 tandem repeats of 15 amino acids was constructed and transfected using a Venus vector into HEK 293T cells. The fluorescent cells, which were considered to express Muc21, were nonadherent. This antiadhesion effect was lessened when constructs with smaller numbers of tandem repeats were used, suggesting that the tandem repeat domain plays a crucial role. Cells expressing Muc21 were significantly less adherent to each other and to extracellular matrix components than control cells. Antibody binding to the cell surface integrin subunits alpha5, alpha6, and beta1 was reduced in Muc21 transfectants in a tandem repeat-dependent manner, whereas equal amounts of proteins were detected by Western blot analysis. Muc21 was expressed as a large glycoprotein that was highly glycosylated with O-glycans at the cell surface, as detected by flow cytometry, Western blotting, and lectin blotting. Although at least a portion of Muc21 was glycosylated with sialylated glycans, removal of sialic acid did not influence the prevention of adhesion.