Isolation of human monoclonal antibodies that bind to two different antigens and are encoded by germline VH and VL genes.

This paper reports isolation of two monoclonal antibodies (mAbs) that bind to both a membrane protein and a cytoplasmic protein. Most Abs established as markers for autoimmune disease bind to cytoplasmic or nuclear substances. However, it remains unknown how these Abs are produced. On the other hand, there were examples where clones originally isolated as Abs that bind to membrane proteins also showed binding activity to cytoplasmic or nuclear substances. Based on these results, the following hypothesis has been proposed. The Abs that had been originally produced against a membrane protein showed cross-reactivity against cytoplasmic or nuclear substances. In the present study we reported isolation of Abs that bound to both a membrane protein, CADM1, and a cytoplasmic protein, α-actinin-4. The method adopted in the present study could be generally applicable to isolation of Abs showing such dual specificity. Firstly, we constructed a huge human Ab library using various organs including naïve B-cell-rich organs such as bone marrow and umbilical cords. Then, we developed a comprehensive screening method for isolation of Abs that bound to cell surface antigens. Through extensive screenings with many kinds of cell we newly obtained a library composed of around 4000 independent clones that bind to membrane proteins. We screened this library with α-actinin-4 and succeeded in isolating two Abs. They bound to α-actinin-4 and a membrane protein CADM1. Furthermore, they are encoded by naïve heavy and light chain variable genes (VH & VL). These results suggested that cross-reactive Abs to both a membrane protein and a cytoplasmic protein could be present in germline repertoire of Ab in humans. This methodology adopted in the present study could be applied to isolation of cross-reactive Abs possibly involved in autoimmune diseases.

Histological evaluation of alveolar ridge augmentation using injectable calcium phosphate bone cement in dogs.

Alveolar ridge augmentation is an important procedure to restore tooth loss. Several types of graft materials have been used for augmenting the alveolar ridge. An injectable calcium phosphate cement (CPC) has been applied to periodontal bone defects and has shown favourable results. Thus, this CPC may work as an effective graft material for alveolar ridge augmentation. The aim of this study was to evaluate the effectiveness of the CPC for large-scaled (about 7 x 8 x 6 mm) ridge augmentation in dogs. Alveolar ridge defects were created bilaterally in the maxilla of six beagle dogs. The CPC was applied to one of the bilateral maxillary defects. The untreated defect on the contralateral side served as control. The animals were sacrificed at 6 months after surgery and decalcified histological specimens of the alveolar ridge were prepared histometrically and evaluated under a light microscope. Newly formed and reconstructed alveolar ridges covering the CPC were observed in all experimental sites. In the control sites, only slight newly bone formation was observed. Histomorphometrical analysis indicated that the CPC grafted group exhibited significantly (P = 0.0001) increased area and height in new bone formation compared with those of the control group. The results indicate that the CPC appears to be an effective material for alveolar ridge augmentation and may act as a space maintainer to conduct new bone formation.

Quantitative relationships between pigment-related mRNA and biochemical melanoma markers in melanoma cell lines.

The use of reverse transcription polymerase chain reaction (RT-PCR) analysis of melanoma-specific transcripts for the identification of circulating melanoma cells has shown very variable results in different studies on melanoma patients. We have therefore developed quantitative methods to study both analytical and biological variations as possible causes of this phenomenon. Pigment-related and S-100 beta transcripts were quantified in 12 different melanoma cell lines and related to the amounts of 5-S-cysteinyldopa, pigment and S-100B protein. A real-time PCR method was used and the results were expressed as absolute number of transcripts per cell. Tyrosinase, tyrosinase-related protein (TRP)-1, TRP-2 and MART-1/Melan-A mRNA varied from undetectable (< 10(-4) transcripts/cell) to 10(3) transcripts/cell, i.e. by a factor > 10(7) in the different cell lines. S-100 beta mRNA varied from 2.8 to 165 transcripts/cell, i.e. by a factor of 60. Tyrosinase, TRP-1 and TRP-2 mRNA correlated significantly with the amount of 5-S-cysteinyldopa, an intermediate pigment metabolite (P < 0.001, P < 0.001 and P < 0.01, respectively). The amount of S-100 beta mRNA correlated significantly with the amount of S-100B protein (P < 0.001). No cross-correlations were seen between the pigment-related and S-100-related analytes. We conclude that one reason behind the negative results of RT-PCR measurement of pigment-related mRNA may be that these transcripts are not always expressed in the particular cells present in the patient's blood. Furthermore, variation in the expression of the order of 10(7) must have great impact on the diagnostic sensitivity. Measurement of S-100 beta mRNA would be more sensitive, but the use of this transcript is hampered by its presence in the blood cells.

Contribution of sodium channel and sodium/hydrogen exchanger to sodium accumulation in the ischemic myocardium.

Contribution of sodium channels and sodium/hydrogen exchangers (NHEs) to sodium accumulation during ischemia in the ischemic/reperfused heart was examined. Ischemia increased the myocardial sodium. Reperfusion elicited a further increase in the myocardial sodium, which was associated with little recovery of the left ventricular developed pressure (LVDP) of the perfused heart. Treatment with tetrodotoxin or dimethylamirolide (DMA) dose-dependently attenuated the ischemia- and reperfusion-induced increase in myocardial sodium and enhanced the post-ischemic recovery of the LVDP. There was an inverse relationship between the increase in myocardial sodium during ischemia and the post-ischemic recovery of the LVDP.The myocardial sodium accumulation during ischemia is mainly attributed to sodium influx through sodium channels and NHEs.

Spirostanols obtained by cyclization of pseudosaponin derivatives and comparison of anti-platelet agglutination activities of spirostanol glycosides.

Naturally occurring saponins 3 and 4 have a normal type F ring and alpha-arranged CH(3)-21 group. Treatments of pseudosaponin peracetates 18 and 19 derived from 3 and 4, respectively, with alcoholic KOH, followed by acidification with acetic acid, gave spirostanols 20 and 22 having iso type F rings as major products. Structural analyses of sapogenins and saponins derived from pseudo derivatives 11, 12, 18 and 19 were performed by comparisons of their 1H-NMR spectral data and the X-ray analytical data of 3-O-p-bromobenzoyl sarsasapogenin 7, 3-O-acetyl diosgenin 13 and saponin 20. The mechanisms of ring-closure reaction of the side chain at C-22 of pseudosapogenins and pseudosaponins were deduced using stereomodels of the spirostanols derived from 11 under various reaction conditions. Inhibitory activities of saponin diglycosides 3, 4, 20, 21 and 25 on human platelet agglutinations induced by ADP and ristocetin were compared.

Cell-type specificity of l-leucyl l-leucine methyl ester.

l-Leucyl l-leucine methyl ester (LeuLeuOMe) is a lysosomotropic agent which is converted to a membranolytic compound by dipeptidyl peptidase I and kills human leukocytes such as CD8+ T cells and monocytes but not B cells. The reagent has also been used in mice on the assumption that the cell-type specificity to murine leukocytes is the same as that to human leukocytes. During study on the effect of LeuLeuOMe on antigen-driven IL-2 production using murine splenocytes as antigen-presenting cells, however, we noticed that murine B cells were sensitive to LeuLeuOMe. We therefore examined the cell-type specificity using murine splenocytes and peritoneal macrophages. Flow cytometric analysis revealed that the most sensitive cells to LeuLeuOMe were CD8+ cells and that CD19+ cells (B cells) were as sensitive as CD3+ cells (T cells). Murine splenic B cells, which were either positively or negatively sorted with a cell sorter, were also sensitive to LeuLeuOMe, whereas human peripheral blood B cells, which were positively sorted, were not. Peritoneal macrophages were the most insensitive to LeuLeuOMe. Thus, this study demonstrated that the cell-type specificity to murine leukocytes is different from that to human leukocytes.

1H-NMR and raman studies on perforating trauma-induced cataract formation in a mouse lens.

In order to provide new insight into the molecular mechanism of perforating trauma-induced cataract formation in an 8-week-old ddY mouse lens, we performed an in situ investigation into changes in the water-protein and/or protein-protein interactions by using 500 MHz (1)H-NMR spectroscopy, and into structural alterations in lens proteins by using Raman spectroscopy. Cross-relaxation times of water protons in the perforated opaque lens were considerably shorter than those in the intact transparent lens, whereas there was no significant difference in water content, suggesting a drastic change in water-protein and protein-protein interactions in the perforated lens. In addition, there was no significant difference in the intensity ratios of several key Raman bands between intact and perforated lenses, indicating that no significant local and overall conformational changes in lens protein itself occur in the perforated lens. The present (1)H-NMR and Raman results lead us to the conclusion that changes leading to lens opacification in the perforating trauma-induced cataract appear to involve the rapid formation of immobile large lens protein aggregates without formation of intra- and intermolecular disulfide linkages, and rapid increase in a fraction of bound water associated with large protein aggregates.

Relationship between myocardial cation content and injury in reperfused rat hearts treated with cation channel blockers.

A role for K+ and Ca2+ channel blockers in cardiac contractile dysfunction and myocardial ionic imbalance was examined in isolated rat hearts with 35-min ischemia and 60-min reperfusion. The K+ channel blockers glibenclamide (1-30 microM) and sematilide (1-30 microM), Ca2+ channel blockers diltiazem (0.1-3 microM) and nicardipine (0.03-1 microM) and fast Na+ channel blocker tetrodotoxin (0.01-0.3 microM) were delivered for the last 3-min pre-ischemia. Ischemia-induced increase in Na+ content was attenuated by diltiazem and tetrodotoxin at all concentrations employed and by nicardipine at 0.3 microM, whereas the ischemia-induced loss of K+ was suppressed partially by glibenclamide and sematilide and almost completely by the two drugs in combination. Left ventricular developed pressure of untreated hearts did not recover upon reperfusion, which was associated with increases in myocardial Na+ and Ca2+ contents and decreases in K+ and Mg2+ contents. Glibenclamide and sematilide neither enhanced the post-ischemic recovery of left ventricular developed pressure nor affected cation changes during reperfusion. Diltiazem enhanced the recovery of left ventricular developed pressure and attenuated imbalance of the myocardial Na+ during ischemia and of all myocardial cations examined during reperfusion. The effects of nicardipine on these parameters were small. Tetrodotoxin enhanced the recovery of left ventricular developed pressure and reversed the imbalance of all myocardial cations examined during reperfusion in a concentration-dependent manner. The results suggest that blockade of transmembrane flux of K+ during ischemia plays a minor role in the improvement of post-ischemic contractile recovery, rather blockade of transmembrane flux of Na+ attenuates the ischemia and reperfusion injury.

Identification of the calmodulin-binding domain of neuron-specific protein kinase C substrate protein CAP-22/NAP-22. Direct involvement of protein myristoylation in calmodulin-target protein interaction.

Various proteins in the signal transduction pathways as well as those of viral origin have been shown to be myristoylated. Although the modification is often essential for the proper functioning of the modified protein, the mechanism by which the modification exerts its effects is still largely unknown. Brain-specific protein kinase C substrate, CAP-23/NAP-22, which is involved in the synaptogenesis and neuronal plasticity, binds calmodulin, but the protein lacks any canonical calmodulin-binding domain. In the present report, we show that CAP-23/NAP-22 isolated from rat brain is myristoylated and that the modification is directly involved in its interaction with calmodulin. Myristoylated and non-myristoylated recombinant proteins were produced in Escherichia coli, and their calmodulin-binding properties were examined. Only the former bound to calmodulin. Synthetic peptides based on the N-terminal sequence showed similar binding properties to calmodulin, only when they were myristoylated. The calmodulin-binding site narrowed down to the myristoyl moiety together with a nine-amino acid N-terminal basic domain. Phosphorylation of a single serine residue in the N-terminal domain (Ser5) by protein kinase C abolished the binding. Furthermore, phosphorylation of CAP-23/NAP-22 by protein kinase C was also found myristoylation-dependent, suggesting the importance of myristoylation in protein-protein interactions.

An expression system of rat calmodulin using T7 phage promoter in Escherichia coli.

An efficient expression system of rat calmodulin in Escherichia coli is presented. To express rat calmodulin cDNA, we employed a pET expression vector which contains the T7 phage promoter and terminator. After transformation of E. coli BL21(DE3) strain which carries T7 phage RNA polymerase inducible with isopropyl-beta-D-thiogalactopyranoside, induction of the expression, and chromatography of soluble proteins on a phenyl-Sepharose column, about 250 mg of recombinant rat calmodulin was obtained from 1 liter of E. coli culture. The recombinant calmodulin lacked the N-terminal methionine, and posttranslational modifications such as Nalpha-acetylation and methylation. This system facilitates the large amount preparation of calmodulin and the mutant proteins required for the structural analysis by NMR spectrometry and/or X-ray crystallography.

[Effect of vaginal antibiotics suppository on retroperitoneal-space infection after hysterectomy and lymphadenectomy for uterine cancer].

Effects of vaginal antibiotics suppository on the retroperitoneal-space infection were studied in 42 patients who had hysterectomy and lymphadenectomy with diagnosis of uterine cancer stage I or II. All patients received intravenous administration of 1 g LMOX (3 times/day) for 7 days after operation. One group of patients (21 cases) received 0.5 g of ABPC vaginal suppository (twice/day) for 10 days immediately after operation. Another group of 21 patients did not received vaginal suppository. The LMOX concentrations in the exudate decreased rapidly from the 3rd day to the 7th day. The frequencies of bacterial appearance in the retroperitoneal-space in the vaginal suppository group were 33% on 5th day, 33% on 7th day and 20% on 9th day, while those in the control group were 100%, 100% and 76%, respectively. It was concluded that the administration of vaginal antibiotics suppository was easy to handle and effective for preventing the retroperitoneal-space infection after hysterectomy and lymphadenectomy.

[Regulation of progesterone accumulation in dissociated luteal cells on day 15 of pregnancy in rats].

Luteal cells from the corpora lutea of rats on day 15 of pregnancy were suspended in DMEM-F12 and progesterone accumulation was measured by radioimmunoassay. Progesterone accumulation increased steadily over eight hours and then gradually decreased. Progesterone accumulation was seen to increase with the addition of BSA and 25-hydroxycholesterol. At doses of 12 ng/ml and 600 ng/ml hCG, progesterone accumulation increased, but was seen to decrease at a dose of 30 micrograms/ml hCG. However, the addition of cyclohexamide alone had no effect on progesterone accumulation, but the simultaneous addition of cyclohexamide and hCG blocked the effects of hCG in a dose related manner. These data indicate that progesterone production by rat luteal cells depends on cholesterol availability. The results reveal that hCG stimulates progesterone production by a process requiring new protein synthesis.