Long-term results of living-related donor liver graft transplantation: a single-center analysis of 110 transplants

BACKGROUND

Difficulties of cadaveric donation and serious donor shortage have led to the development and popularization of living-related donor liver graft transplantation (LRLT). Because the history of this procedure is rather short, important aspects specific to this procedure have not been sufficiently documented. The objective of this study was to analyze a single center's 10-year experience with 110 LRLT in pediatric and adult patients with end-stage liver diseases.

METHODS

The medical records of 110 consecutive patients who underwent LRLT were reviewed. The recipients were comprised of 72 children and 38 adults. The graft volume corresponded to 26-192% of the recipient's standard liver volume. The relationship between pretransplant covariates and patient and graft survival was analyzed. Actuarial patient/graft survival rates were determined at 1, 3, and 5 years. The type and incidence of posttransplant complications were analyzed, as was long-term graft function.

RESULTS

The 1-, 3-, and 5-year actuarial patient and graft survival rates were 88%, 85%, and 85%, respectively. Log-rank test demonstrated that ABO-compatibility predicted patient survival rate, whereas patient age, underlying disease, patient's clinical status, donor-recipient relation, donor age, and graft volume/standard liver volume ratio did not. Long-term liver function remains excellent. All the donors have returned to normal daily lives with an uneventful course.

CONCLUSIONS

LRLT is an efficacious procedure that provides excellent short-term and long-term survival. The indication criteria for both recipient and donor were legitimate in this series, except for transplant across ABO-incompatibility. Cautious expansion of this procedure may be justified under the situation of serious shortage of cadaveric donor.

Questionnaire relating to sleep paralysis

A sleep survey was conducted on 8162 citizens. The cumulative experience rate of sleep paralysis was 39.6%. The initial occurrence of sleep paralysis peaked at age 16 years. In addition to being higher in young people than in older subjects, the incidence of sleep paralysis was also higher among women than among men, and was significantly higher among shift worker than non-shift worker, and among persons engaged in the nursing profession than those not engaged in the nursing profession. The experience rate of sleep paralysis demonstrated a strong correlation with the frequency of dreaming, the experience rate of nightmares, times and regularity of going to bed and waking up, and particularly with the degree of insomnia.

A possible role for maternal HLA antibody in a case of alloimmune neonatal neutropenia

BACKGROUND

Alloimmune neonatal neutropenia (ANN) is caused by a reaction of maternal alloantibodies with paternally inherited antigens on the fetal neutrophils. While human neutrophil antigens (HNA) antibodies are found in half of ANN cases, specific antibodies have not been defined in the remaining cases.

STUDY DESIGN AND METHODS

Reported here is a neonate with omphalitis due to neutropenia. To elucidate the cause of ANN, flow cytometric and PCR analyses were used. Reactions of the patient's and mother's sera with neutrophils, lymphocytes, and platelets were examined by lymphocytotoxicity test (LCT), anti-human immunoglobulin-LCT, and mixed passive hemagglutination test.

RESULTS

The maternal sera reacted with neutrophils, lymphocytes, and platelets of the patient and father. The platelet adsorption eliminated the reaction of the maternal serum with the patient's neutrophils. The HLA typing of the family and an LCT using a panel of lymphocytes of 20 HLA-typed donors showed HLA-A2 antigen as a target of antibodies in the maternal serum. According to anti-human immunoglobulin-LCT, the anti-HLA-A2 was present in the neonatal serum. On the other hand, HNA antibodies were not detectable in the patient's or the mother's serum.

CONCLUSION

These results suggest that the transplacental passage of the maternal HLA antibody caused neutropenia in this patient.

Structure of Bombyx mori silk fibroin before spinning in solid state studied with wide angle x-ray scattering and (13)C cross-polarization/magic angle spinning NMR

The structure of a crystalline form of Bombyx mori silk fibroin, commonly found before the spinning process (known as silk I), has been proposed as a repeated beta-turn type II-like structure by combining data obtained from solid-state two dimensional spin-diffusion nuclear magnetic resonance and rotational-echo double-resonance (T. Asakura et al., J Mol Biol, in press). In this paper, the WAXS pattern of alanine-glycine alternating copolypeptide, (Ala-Gly)(15) with silk I form which was used for a silk I model of B. mori silk fibroin was observed. The pattern calculated with the silk I model proposed by us is well reproduced the observed one, indicating the validity of the proposed silk I model. In addition, two peptides of the other repeated sequences which contain Tyr or Val residues in the silk fibroin,23 were synthesized; (Ala-Gly-Tyr-Gly-Ala-Gly)(5) and (X-Gly)(15) where X is Tyr for the 7th, 15th and 23th residues, and Val for the 11th residue and Ala for other residues. There are no sharp peaks in the WAXS patterns, and therefore both samples are in the non-crystalline state. This is in agreement with the (13)C CP/MAS NMR result, where the conformation is mainly random coil.

An increase in circulating mast cell colony-forming cells in asthma

We compared a potential to generate mast cells among various sources of CD34(+) peripheral blood (PB) cells in the presence of stem cell factor (SCF) with or without thrombopoietin (TPO), using a serum-deprived liquid culture system. From the time course of relative numbers of tryptase-positive and chymase-positive cells in the cultured cells grown by CD34(+) PB cells of nonasthmatic healthy individuals treated with G-CSF, TPO appears to potentiate the SCF-dependent growth of mast cells without influencing the differentiation into mast cell lineage. CD34(+) PB cells from asthmatic patients in a stable condition generated significantly more mast cells under stimulation with SCF alone or SCF+TPO at 6 wk of culture than did steady-state CD34(+) PB cells of normal controls. Single-cell culture studies showed a substantial difference in the number of SCF-responsive or SCF+TPO-responsive mast cell progenitors in CD34(+) PB cells between the two groups. In the presence of TPO, CD34(+) PB cells from asthmatic children could respond to a suboptimal concentration of SCF to a greater extent, compared with the values obtained by those of normal controls. Six-week cultured mast cells of asthmatic subjects had maturation properties (intracellular histamine content and tryptase/chymase enzymatic activities) similar to those derived from mobilized CD34(+) PB cells of nonasthmatic subjects. An increase in a potential of circulating hemopoietic progenitors to differentiate into mast cell lineage may contribute to the recruitment of mast cells toward sites of asthmatic mucosal inflammation.

A repeated beta-turn structure in poly(Ala-Gly) as a model for silk I of Bombyx mori silk fibroin studied with two-dimensional spin-diffusion NMR under off magic angle spinning and rotational echo double resonance

The structure of a crystalline form of Bombyx mori silk fibroin, commonly found before the spinning process (known as silk I), was proposed by combining data obtained from two-dimensional spin-diffusion nuclear magnetic resonance under off magic angle spinning, rotational-echo double-resonance (REDOR), previously reported X-ray diffraction analyses and 13C NMR chemical shifts. Instead of B. mori silk fibroin with silk I structure, we used the sequential model peptide (Ala-Gly)15. The structure of the sequential model peptide is characterized as silk I after dissolving the peptide in 9 M LiBr and then dialyzing against water. Moreover, 13C or 15N-labeled sites may be introduced easily at any position in (Ala-Gly)(15) by the solid phase synthesis method for these NMR experiments. The torsional angles of (Ala-Gly)15 with silk I structure were determined as (-60(+/-5) degrees, 130(+/-5) degrees ) and (70(+/-5) degrees, 30(+/-5) degrees ) for Ala and Gly residues, respectively. The formation of the intra-molecular hydrogen bonding along the chain was confirmed from REDOR NMR by determination of the inter-atomic distance between the nitrogen and carbon atoms comprising the intra-molecular hydrogen bonding. The structure is named a repeated beta-turn type II-like structure.

Angiographically documented coronary steal phenomenon evoked by the intracoronary infusion of bradykinin

While studying flow-dependent coronary dilation using a Doppler flow velocity guidewire, total occlusion of a stenosed segment of the left circumflex artery during the intracoronary infusion of bradykinin was angiographically documented. Total occlusion was not demonstrated during intracoronary infusion of bradykinin after angioplasty. This is angiographic confirmation of the coronary steal phenomenon that has been previously described in the field of stress scintigraphy.

[Efficacy of radiofrequency catheter ablation in a patient with sinus node reentrant tachycardia]

We performed electrophysiological study and catheter ablation on a 62-year-old patient with supraventricular tachycardia(SVT). This SVT was reproducibly initiated and terminated by atrial stimulation during the electrophysiological testing. The P-wave morphology and atrial activation sequence of intracardiac electrograms were identical to those in normal sinus rhythm. SVT was terminated with carotid sinus massage that increased vagal tone, and for this reason, the reentry circuit of SVT could be localized in sinus node. On the basis of these findings, the SVT was diagnosed as sinus node re-entrant tachycardia and was successfully eliminated by radiofrequency catheter ablation. Radiofrequency catheter ablation would be effective in patients with sinus node reentrant tachycardia refractory to anti-arrhythmic drugs. It should, however, be performed with careful consideration to the influence of the sinus node.

A novel antiferromagnetic organic superconductor kappa-(BETS)(2)FeBr(4) [where BETS = bis(ethylenedithio)tetraselenafulvalene]

The electrical and magnetic properties of kappa-(BETS)(2)FeBr(4) salt [where BETS = bis(ethylenedithio)tetraselenafulvalene] showed that this system is the first antiferromagnetic organic metal at ambient pressure (T(N) = 2.5 K). The characteristic field dependence of the magnetization at 2.0 K indicates a clear metamagnetic behavior. The small resistivity drop observed at T(N) clearly shows the existence of the interaction between pi metal electrons and localized magnetic moments of Fe(3+) ions. In addition, this system underwent a superconducting transition at 1.1 K. That is, kappa-(BETS)(2)FeBr(4) is the first antiferromagnetic organic metal exhibiting a superconducting transition below Néel temperature. The magnetic field dependence of the superconducting critical temperature indicated that the superconductivity in this system is strongly anisotropic also in the conduction plane because of the existence of the metamagnetically induced internal field based on the antiferromagnetic ordering of the Fe(3+) 3d spins in contrast to the cases of the other conventional organic superconductors. Furthermore, the specific heat measurement exhibited a lambda-type large peak of zero-field specific heat corresponding to the three-dimensional antiferromagnetic ordering of high-spin Fe(3+) ions. The lack of distinct anomaly in the C(p) vs T curve at T(c) suggests the coexistence of the superconductivity and the antiferromagnetic order below T(c).

Fibrous obliterative lesions of veins contribute to progressive fibrosis in chronic liver allograft rejection

Fibrosis in liver allografts undergoing chronic rejection (CR) is variable and poorly understood. The temporal and spatial relationships of venous, arterial, and biliary lesions were studied to clarify their potential contributions to graft fibrosis. The severity, prevalence, and morphology of intimal lesions of vessels were analyzed and compared with the fibrosis stage. Three groups were found; group 1 (n = 5) with no hepatic vein (HV) lesions, group 2 (n = 5) with HV lesions only, and group 3 with lesions of both HV and portal veins (PV). The earliest lesion to develop, in 71% of grafts, was concentric intimal thickening of small HV. This was significantly more severe and frequent in grafts from group 3. With increasing frequency and severity of small HV sclerosis, fibrosis developed in medium/large veins. The morphology of larger vessel lesions suggested organized thrombus. Centrilobular fibrosis was significantly more severe in group 3 and developed unpredictably and sometimes rapidly. Conversely, portal fibrosis scores were significantly higher in grafts with ductular proliferation and did not correlate with venous lesions. This suggests that in CR, veno-occlusive-like lesions develop commonly in terminal hepatic venules, probably caused by immune-mediated damage. In only a proportion, with increased frequency and severity of the lesions, stasis and thrombosis in portal and larger veins occur and could result in loss of hepatic and portal venous outflow, which leads to ischemia and fibrosis. The stage of fibrosis did not correlate with foam-cell arteriopathy. A second pathway of portal fibrosis occurs in patients with longstanding biliary proliferation.

[Pathological examination for liver transplantation]

Liver biopsy plays an important role in the histopathological evaluation of the transplanted liver. In this review, we would like to describe the histological features of various forms of diseases such as allograft rejections occurring in transplanted livers. When severe steatosis is found in the donor liver, transplantation is contraindicated. Ischemic liver damage caused by transplant hypoperfusion is called harvesting or re-perfusion injury and characterized by the histological features of liver-cell ballooning, centrilobular cholestasis, and apoptosis of hepatocytes. Acute rejection occurring more commonly in the first few weeks after transplantation is defined by the diagnostic triad of portal inflammatory infiltrates, endothelialitis, and bile duct damage, whereas chronic rejection is characterized by the presence of ductopenia and foam cell arteriopathy. Obstruction of the hepatic artery leads to severe centrilobular necrosis of the allograft. Among viral infections affecting the allografts, cytomegalovirus infection occurs most frequently, and typical intranuclear or cytoplasmic inclusions are hallmarks of the infection. Post-transplantation lymphoproliferative disorders are closely associated with Epstein-Barr virus infection. Therapeutic drugs such as azathioprine and cyclosporin A also cause liver damage, but specific histological features of drug-induced injury have not yet been clarified. Recurrence of original diseases such as viral hepatitis or malignant tumors is also evaluated by the liver biopsy.

Retinoic acid is a negative regulator for the differentiation of cord blood-derived human mast cell progenitors

We examined the effects of retinoids on the human mast cell development using a serum-deprived culture system. When 10-week cultured mast cells derived from CD34(+) cord blood cells were used as target cells, both all-trans retinoic acid (ATRA) and 9-cis RA inhibited the progeny generation under stimulation with stem cell factor (SCF) in a dose-dependent manner (the number of progeny grown by SCF plus RA at 10(-7) mol/L was one tenth of the value obtained by SCF alone). The early steps in mast cell development appear to be less sensitive to RA according to the single CD34(+)c-kit(+) cord blood cell culture study. The optimal concentration of RAs also reduced the histamine concentration in the cultured mast cells (3.00 +/- 0.47 pg per cell in SCF alone, 1.44 +/- 0.18 pg per cell in SCF+ATRA, and 1.41 +/- 0.10 pg per cell in SCF+9-cis RA). RT-PCR analyses showed the expression of RARalpha, RARbeta, RXRalpha, and RXRbeta messenger ribonucleic acid (mRNA) in 10-week cultured mast cells. The addition of an RAR-selective agonist at 10(-10) mol/L to 10(-7) mol/L decreased the number of mast cells grown in SCF, whereas an RXR-selective agonist at up to 10(-8) mol/L was inactive. Among RAR subtype selective retinoids used at 10(-9) mol/L to 10(-7) mol/L, only the RARalpha agonist was equivalent to ATRA at 10(-7) mol/L in its ability to inhibit mast cell growth. Conversely, the addition of excess concentrations of a RARalpha antagonist profoundly counteracted the retinoid-mediated suppressive effects. These results suggest that RA inhibits SCF-dependent differentiation of human mast cell progenitors through a specific receptor. (Blood. 2000;95:2821-2828)

Clinicopathological analysis of liver allograft biopsies with late centrilobular necrosis: a comparative study in 54 patients

BACKGROUND

Centrilobular necrosis (CLN) in liver allografts can be a difficult lesion to interpret histologically. Although long recognized in association with developing chronic rejection, recent studies have described the lesion in association with a number of other disease processes. To clarify the histologic features that could allow a specific diagnosis to be made and to determine the outcome in different diagnostic groups, we assessed biopsies from 54 patients with CLN.

METHODS

Biopsies were classified as CLN with acute cellular rejection (ACR), CLN with hepatitis, CLN with developing chronic rejection (CR), and CLN of other etiology. Histologic features were assessed and then compared between groups, and clinical outcomes were noted.

RESULTS

Discriminating features for the different groups were as follows: CLN and ACR showed bile duct injury, endothelialitis, and acinar congestion. CLN and CR showed severe bile duct injury, bile duct loss, or centrilobular swelling. CLN and hepatitis was often a diagnosis of exclusion, although interface hepatitis was more common in this group. Cases of autoimmune hepatitis usually demonstrated plasma cell predominance in the portal and acinar inflammatory infiltrate. Significantly, there was considerable overlap in the histologic features between the groups, accounting for the diagnostic difficulty. Patients in whom the CLN was associated with CR or vascular complications generally required retransplantation or died, but in the groups with ACR and hepatitis, the outcome was more favorable.

CONCLUSIONS

With regard to most liver allograft biopsies showing late CLN, it is possible to make a specific diagnosis despite overlapping histologic features; this allows specific therapy to be instituted. Ultimately this is likely to contribute to improved graft survival.

First case of cadaveric liver transplantation in Japan

The first case of liver transplantation from a brain-dead donor in Japan is described. The recipient was a 43-year-old man with familial amyloid polyneuropathy who manifested various neuropathic symptoms and autonomic dysfunction at the time of transplantation. The graft had three arteries, for which a single trunk was created at the back table. A side-to-side cavacaval anastomosis was performed as an outflow reconstruction. To avoid portal congestion, a temporary shunt between the right posterior branch of the portal vein and the vena cava was constructed, instead of a venovenous bypass. The graft preservation time was 7.2 h and the operation time was 12.2 h. Although sufficient blood flow in the hepatic artery, portal vein, and hepatic vein was confirmed intra- and postoperatively, using Doppler ultrasound, transient graft dysfunction was observed immediately after surgery, but there was spontaneous improvement. The patient was discharged 100 days after transplantation.

Clinicopathologic findings of recurrent primary sclerosing cholangitis after orthotopic liver transplantation

Whether primary sclerosing cholangitis (PSC) occurs after orthotopic liver transplantation is controversial, largely because the pre-transplant diagnosis of PSC is based on nonspecific radiological and histological findings. We reviewed clinical, radiological, and histological records of 53 patients who underwent liver transplantation for PSC between 1985 and 1998. Three patients with patent hepatic arteries and no evidence of chronic rejection had radiological and histological findings that may have been due to recurrent PSC. Bile duct stricturing in these patients proved permanent and progressive and affected both the quality of life and graft survival. The first patient, who is 110 months after transplantation, has had repeated episodes of cholangitis for the last year. The second patient underwent excision of a strictured hepatic duct 45 months after transplantation and was ultimately retransplanted 95 months after initial transplantation. The third patient underwent left hemihepatectomy of an atrophied lobe 50 months after transplantation. Although the patient population assessed in this study is limited, putative recurrent PSC in the allografts has led either to graft loss or to clinically significant hepatobiliary complications of the graft.

Living-related liver transplantation for patients with fulminant and subfulminant hepatic failure

The prognosis for patients with fulminant (FHF) or subfulminant hepatic failure (SFHF) has improved since the introduction of liver transplantation. However, the death rate of patients awaiting liver transplantation is high, possibly because of the difficulty in obtaining grafts in a timely manner, given the relative shortage of cadaveric donors. Between June 1990 and June 1999, 106 patients underwent living-related liver transplantation (LRLT) at Shinshu University Hospital. Among them, 8 patients had FHF and 6 had SFHF; these 14 patients are the subjects of this report. The graft volumes (GV) ranged from 231 mL to 625 mL, corresponding to 35% to 105% of the recipients' standard liver volume (SLV). The postoperative courses of all donors were uneventful. Following liver transplantation, all grafts functioned favorably, with normalization of serum total bilirubin within 3 to 5 days and normalization of coagulation profiles within 4 to 7 days. Thirteen of the 14 recipients are still alive. The actuarial 6-month, 1-year, and 5-year survival rates were 100%, 90%, and 90%, respectively. In the present study, when the ratio of the GV to the recipient's SLV was more than 35%, the graft was able to support the patient's metabolic demand after liver transplantation for FHF or SFHF. Because of the urgent nature of liver transplantation in this clinical condition, concerns over informed consent may be even greater than for elective LRLT. Nevertheless, the high success rate and low donor risk may justify this option for pediatric patients, as well as for a limited population of adult patients suffering from FHF or SFHF.

The role of laparoscopic US and laparoscopic US-guided aspiration biopsy in the diagnosis of multicentric hepatocellular carcinoma

BACKGROUND

Detection of small hepatocellular carcinomas has become possible with improvements in various diagnostic imaging techniques. However, intraoperative US can detect lesions not visualized by any preoperative imaging study in which case it is difficult to determine whether the lesion is a hepatocellular carcinoma.

METHODS

Nodular lesions detected by laparoscopic US in 186 patients with hepatocellular carcinoma were examined and we evaluated the diagnostic ability of laparoscopic US to detect multicentric hepatocellular carcinoma.

RESULTS

One hundred thirty-four new nodular lesions were detected by laparoscopic US in 64 (34.4%) of 186 patients. Aspiration biopsy under laparoscopic US guidance was performed on the 134 nodules, and 28 nodules in 23 (12.4%) of the 186 patients were histologically diagnosed as hepatocellular carcinoma. Of these 23 patients, 18 had been diagnosed with solitary hepatocellular carcinoma before laparoscopic US. One hundred six of the newly detected lesions were initially diagnosed as noncarcinomatous nodules, but the diagnosis of 10 of these lesions was changed to hepatocellular carcinoma during follow-up that was as long as 96 months.

CONCLUSIONS

Laparoscopic US is useful in the initial diagnosis of hepatocellular carcinoma and impacts treatment selection by more accurately defining the presence of multicentric hepatocellular carcinomas.

Interaction of factor XII and high molecular weight kininogen with cytokeratin 1 and gC1qR of vascular endothelial cells and with aggregated Abeta protein of Alzheimer's disease

High molecular weight kininogen (HK) attaches to endothelial cells at separate sites on the heavy and light chains by a process which requires 15-50 microM zinc. Previously identified binding proteins include gClqR, cytokeratin 1, and the urokinase plasminogen activator receptor (U-par), however, their relative contribution to binding are not yet clarified. We have purified the binding proteins by affinity chromatography, in the presence of zinc ion, and identified cytokeratin 1 and gC1qR by amino acid sequencing of an internal peptide and by immunoblot as heavy chain and light chain binding proteins, respectively. Antibody to cytokeratin 1 inhibited HK binding to endothelial cells by 30%, antibody to gClqR inhibited HK binding to endothelial cells by 72%, and a mixture of both inhibited binding by 86%. The binding and activation of the proteins of the kinin-forming cascade along the cell surface is zinc-dependent. Similarly, proteins of the plasma kinin-forming cascade can be activated by binding to aggregated A(beta) protein of Alzheimer's disease. Activation of the cascade using purified proteins or upon addition of Abeta to plasma requires aggregation of A(beta) and the reactions are zinc-dependent. In plasma, HK is cleaved and bradykinin is liberated. The data demonstrate that aggregated A(beta) can bind and activate proenzymes of the plasma kinin-forming cascade to release bradykinin and these reactions are dependent on zinc ion.

Prognosis of small hepatocellular carcinoma after laparoscopic ethanol injection

BACKGROUND

Most patients with hepatocellular carcinoma have underlying cirrhosis, and this impairment of liver function makes hepatectomy difficult, prompting the use of other modalities such as transcatheter arterial embolization and percutaneous ethanol injection.

METHODS

Laparoscopic ethanol injection was performed in 48 previously untreated patients with hepatocellular carcinoma smaller than 2 cm in diameter. Long-term survival was evaluated.

RESULTS

In 12 patients, hepatocellular carcinoma was not detected by trans-cutaneous ultrasonography but could be demonstrated by laparoscopic ultrasonography. Laparoscopic ethanol injection did not cause serious complications in any patient. The mean hospital stay after ethanol injection was 8.6 days (4 to 15 days). The cumulative survival rate was 86.7% at 3 years and 60.0% at 5 years. According to the Child-Pugh classification, the cumulative survival rate at 5 years was 87.9% for class A, 65.7% for class B, and 28.6% for class C.

CONCLUSIONS

The long-term prognosis for patients with small hepatocellular carcinoma treated solely by laparoscopic ethanol injection is satisfactory but still dependent on underlying liver function.

Platelet glycoprotein Ib: a zinc-dependent binding protein for the heavy chain of high-molecular-weight kininogen

Domains 3 and 5 of high-molecular-weight kininogen (HK) have been shown to bind to platelets in a zinc-dependent reaction. However, the platelet-binding proteins responsible for this interaction have not been identified. We have focused on the platelet-binding site for the heavy chain (domain 3), which we approached using a domain 3-derived peptide ligand and isolated binding proteins by affinity chromatography. The domain 3-derived peptide, thrombin, HK, factor XII, as well as antibody to glycocalicin (the N-terminal portion of the alpha chain of GPIb) recognized a protein at 74 kD. We also isolated the thrombin receptor (PAR 1) at 45 kD, however, none of the above-mentioned ligands bound to this protein. Isolation of platelet membrane proteins using a monoclonal anti-glycocalicin antibody column revealed the same HK binding protein at 74 kD, which was reactive with anti-GPIb and represents a GPIb fragment. By photoaffinity labeling, HK interacted with membrane GPIb, which was then isolated in native form (135 kD) along with gC1qR, a ligand for the HK light chain. Finally, (125)I-HK binding to platelets was significantly inhibited by the anti-GPIb antibody. These results suggest that the GPIb alpha chain, a known thrombin binding protein, is also one of the zinc-dependent platelet membrane binding sites for HK domain 3.

Microhardness evaluations of resin-dentin bonding areas by nano-indentation

The purpose of this experiment was to determine the hardness values of the hybrid layer and its surroundings through the continuous use of a microhardness measuring device. Black's Class V cavities were prepared in nine dog teeth. The cavities were divided into four groups according to the dentin adhesive system applied. The adhesive systems were: "Bond One System", "Liner Bond II sigma System", "One Step System", and "Single Bond System". The treated teeth were observed at seven days post-application. Specimens were cross-sectioned perpendicularly or horizontally to the resin-dentin interface and embedded in epoxy resin. Their surfaces were polished. The microhardness of the resin-dentin bonding area was measured with a nano-indentation tester. The hardness values at a point of 10 microns distant from the interface in the direction of the dentin differed between systems. It appeared that this was influenced by the presence of the decalcified dentin not impregnated by resin, differences in the chemistry forming the hybrid layer, and the composition of the bonding resin. The hardness of the dentin-bonding interface and its surroundings was determined, and these areas were observed using SEM. Three layers were confirmed the healthy dentin layer, the composite resin layer, and the hybrid layer, (in which decalcified dentin impregnated by resin and that not impregnated by resin are considered to be mix). In the hybrid layer, no impression was found by SEM although the hardness in the bonding interface was significantly different. These layers appear to be more elastic and softer than the healthy dentin.

Zinc-dependent activation of the plasma kinin-forming cascade by aggregated beta amyloid protein

Beta Amyloid proteins (Abeta) of 38, 40, and 42 amino acids long were assessed for their ability to activate the plasma kinin-forming cascade in vitro. Incubation with a mixture of Factor XII (Hageman Factor), prekallikrein, and high-molecular-weight kininogen (HK) led to conversion of prekallikrein to kallikrein that was dependent on zinc ion. No activation occurred if Factor XII was omitted. There was rapid generation of bradykinin equal to the molar HK input indicating complete cleavage. Incubation of aggregated Abeta with diluted human plasma also led to prekallikrein activation and HK cleavage. Activation of the cascade by Abeta (1-38) was dependent upon its preincubation time in buffer, suggesting that aggregation of Abeta is required, and studies with Abeta (1-40) revealed time-dependent aggregation by microscopy and augmented zinc-dependent binding of both Factor XII and HK to aggregated Abeta. These data demonstrate that aggregated Abeta can bind and activate proenzymes of the plasma kinin-forming cascade in a zinc-dependent reaction to release bradykinin and is of sufficient potency to do so at physiologic concentrations of each protein and in the presence of naturally occurring protease inhibitors.