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 (V_H & V_L). 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.

Web survey-based selection of controls for epidemiological analyses of a multi-prefectural outbreak of enterohaemorrhagic Escherichia coli O157 in Japan associated with consumption of self-grilled beef hanging tender

An outbreak of enterohaemorrhagic Escherichia coli O157 occurred in multiple prefectures of Japan in November 2009. We conducted two case-control studies with trace-back and trace-forward investigations to determine the source. The case definition was met by 21 individuals; 14 (66.7%) were hospitalised, but no haemolytic uraemic syndrome, acute encephalopathy or deaths occurred. Median age was 23 (range 12-48) years and 14 cases were male (66.7%). No significant associations with food were found in a case-control study by local public health centres, but our matched case-control study using Internet surveys found that beef hanging tender (or hanger steak), derived from the diaphragm of the cattle, was significantly associated with illness (odds ratio = 15.77; 95% confidence interval, 2.00-124.11). Pulsed-field gel electrophoresis analysis of isolates from patients and the suspected food showed five different patterns: two in faecal and food samples, and another three in patient faecal samples only, although there were epidemiological links to the meat consumed at the restaurants. Trace-back investigation implicated a common food processing company from outside Japan. Examination of the logistics of the meat processing company suggested that contamination did not occur in Japan. We concluded that the source of the outbreak was imported hanging tender. This investigation revealed that Internet surveys could be useful for outbreak investigations.

[A case of liver metastasis from sigmoid colon cancer treated effectively by second-line chemotherapy]

A case of successful chemotherapy for a metachronous liver metastasis following resection for sigmoid colon cancer is presented. A 51-year-old man underwent sigmoidectomy, ileocecal resection, and descending colon colostomy for sigmoid colon cancer with ileum invasion. Six courses of FOLFOX4 were performed as adjuvant chemotherapy. One year after sigmoidectomy, a liver metastasis was detected on computed tomography (CT) examination. Chemotherapy with FOLFOX+bevacizumab was restarted. Three courses were administered, but hepatic dysfunction occurred after the second and third courses, and FOLFOX was discontinued. Subsequent chemotherapy was reinitiated with FOLFIRI+bevacizumab. After 9 courses, the carcinoembryonic antigen level was normalized and appeared to be decreased by imaging studies. Upon the patient's request, only oral S-1 was administered. After 2 courses, CT revealed that the diameter of the tumor had increased by 2 cm. Therefore, right lobectomy of the liver, colostomy closure, and anastomosis were performed. During these procedures, a nodule was found in the omentum and was removed. Rapid intra-operative diagnosis revealed peritoneal dissemination. The pathological diagnosis was liver metastasis of sigmoid colon cancer, with necrosis and fibrosis seen in approximately one-half of specimens. The surgical margins were negative. Neither metastatic cancer nor dissemination were found in the resected greater omentum.

[A case of Stage IV gastric cancer was successfully treated with multi combination chemotherapy with S-1]

Stage IV gastric cancer has poor prognosis, and median survival time (MST) is reported to range from 6 to 13 months. We report a case of long-term survival in a Stage IV gastric cancer patient who was successfully treated with multi combination chemotherapy with S-1. A 73-year-old woman presenting with gastric cancer with pyloric stenosis and peritoneal dissemination at the sigmoid colon underwent distal gastrectomy with D2 lymphadenectomy and sigmoidectomy. She received adjuvant chemotherapy with S-1 and CDDP after surgery. During the twelfth administration of S-1 and CDDP, she developed an anaphylactic reaction against CDDP; therefore, only S-1 was administered for the next 6 courses. Thirty one months postgastrectomy, a left ovarian metastasis (about 4 cm) was detected by computed tomography. Two courses of S-1 and CPT-11 were administered; however, the ovarian metastasis grew to twice its initial size. She underwent hysterectomy and bilateral ovariectomy. The pathological diagnosis was metastatic tumors in the uterus and ovary(Krukenberg tumor). After the second surgery, S-1 and docetaxel therapy was initiated. A metastasis (S2, 5mm diameter) appeared in the right lung around 65 months after the gastrectomy. The patient received a total of 28 courses, up until 69 months post-gastrectomy. At present, she hopes to finish the chemotherapy and is consulting a palliative care facility. At 80 months post-gastrectomy, she has no symptoms because the lung metastasis exhibits slow growth (15 mm diameter), and is maintaining her quality of life (QOL).

[A case of rectal cancer with multiple liver metastases successfully treated by repeated hepatectomy]

A 61-year-old man was diagnosed with rectal cancer with multiple liver metastases in December 2009, and low anterior resection of the rectum was performed. Postoperative adjuvant chemotherapy with 6 courses of oxaliplatin, Leucovorin, and 5-FU (FOLFOX4) and bevacizumab was initiated, followed by 5 courses of fluorouracil, Leucovorin, and irinotecan (FOLFIRI) and bevacizumab. Right posterior segment (S6, S7) hepatectomy with enucleation of S2, S3 and S5 was performed, and chemotherapy with FOLFOX4 (11 courses) was administered. New metastases in the S5 segment were observed in August 2011 and right hepatic lobectomy was performed. The patient then underwent 8 courses of adjuvant chemotherapy with FOLFOX4. However, left hepatic lobe lateral segment and caudate lobe metastases then appeared. Subsequent repeated chemotherapy with FOLFIRI plus cetuximab (3 courses) and irinotecan plus cetuximab was interrupted in August 2013 owing to adverse events resulting in rapid growth of hepatic metastases. The patient underwent hepatic left lateral segmentectomy and left caudate lobectomy. The postoperative course was uneventful and the patient has currently survived 4 years and 7 months after the initial surgery.

Real space observation of current-induced magnetic domain wall displacement in Co/Ni nano-wire by photoemission electron microscopy

Current-induced magnetic domain wall (DW) displacement in a Co/Ni nano-wire with perpendicular magnetic anisotropy was investigated in real space by photoemission electron microscopy (PEEM) for the first time. DW velocity determined from the PEEM observation was 40 m s(-1) for the current density of 2.5 × 10(12) A m(-2), which was consistent with the result obtained by the electrical measurement used in our previous reports.

Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire

The spin transfer torque is essential for electrical magnetization switching. When a magnetic domain wall is driven by an electric current through an adiabatic spin torque, the theory predicts a threshold current even for a perfect wire without any extrinsic pinning. The experimental confirmation of this 'intrinsic pinning', however, has long been missing. Here, we give evidence that this intrinsic pinning determines the threshold, and thus that the adiabatic spin torque dominates the domain wall motion in a perpendicularly magnetized Co/Ni nanowire. The intrinsic nature manifests itself both in the field-independent threshold current and in the presence of its minimum on tuning the wire width. The demonstrated domain wall motion purely due to the adiabatic spin torque will serve to achieve robust operation and low energy consumption in spintronic devices.

Transient decreases in Bispectral Index without associated changes in the level of consciousness during photic stimulation in an epileptic patient

This case report describes a patient with a history of epileptic seizures who showed unusual decreases in the Bispectral Index (BIS) attributable to the induction of abnormal slow electroencephalographic (EEG) waves by photic stimulation, without any associated decrease in his level of consciousness. After starting anticonvulsive therapy, photic stimulation no longer induced abnormal EEG activity nor decreased BIS values. These findings suggest that BIS values may not accurately reflect a patient's actual level of consciousness in the presence of epilepsy-related abnormal EEG activity and that the BIS monitor may be able to track such EEG changes.

[Aortic regurgitation caused by rupture of a fibrous strand; report of a case]

Rupture of a fibrous strand of a tricuspid aortic valve is extremely rare. We describe a patient with aortic regurgitation due to spontaneous rupture of the fibrous strands that suspend the aortic valve leaflets. The fibrous strands were recognized between the left and right coronary cusps, and between the left coronary and non-coronary cusps during the operation. The fibrous strand between the left coronary and non-coronary cusps had been ruptured, and thus the left coronary and non-coronary cusps were prolapsed into the left ventricle. Since a degenerative change was observed histologically in the resected specimen, these fibrous strands were considered to be an embryonic remnant of the aortic valve.

System design of a bioartificial liver with a high performance hemodialyzer as an immunoisolator using a mathematical kinetic model

We propose a new bioartificial liver (BAL) system equipped with a high performance hemodialyzer to act as an immunoisolation device. We discuss the design of the BAL system using a mathematical kinetic model with the experimentally obtained mass-transfer performances of various hemodialyzers. The mass transfer resistances of the hemodialyzers did not adversely influence the ammonia-removal and bioactive-substance-supply performances of the BAL system. A suitable hemodialyzer for the BAL system is available even at present using an engineering design. The remaining problems to be overcome before realizing clinical use of the BAL system are to increase the rate constant of the first order reaction of the BAL for ammonia metabolism and to develop a new method of blood access that can be used safely with long term reliability at a high blood flow rate (ca. 556 ml/min).

Ectopic expression of DREF induces DNA synthesis, apoptosis, and unusual morphogenesis in the Drosophila eye imaginal disc: possible interaction with Polycomb and trithorax group proteins

The promoters of Drosophila genes encoding DNA replication-related proteins contain transcription regulatory element DRE (5'-TATCGATA) in addition to E2F recognition sites. A specific DRE-binding factor, DREF, positively regulates DRE-containing genes. In addition, it has been reported that DREF can bind to a sequence in the hsp70 scs' chromatin boundary element that is also recognized by boundary element-associated factor, and thus DREF may participate in regulating insulator activity. To examine DREF function in vivo, we established transgenic flies in which ectopic expression of DREF was targeted to the eye imaginal discs. Adult flies expressing DREF exhibited a severe rough eye phenotype. Expression of DREF induced ectopic DNA synthesis in the cells behind the morphogenetic furrow, which are normally postmitotic, and abolished photoreceptor specifications of R1, R6, and R7. Furthermore, DREF expression caused apoptosis in the imaginal disc cells in the region where commitment to R1/R6 cells takes place, suggesting that failure of differentiation of R1/R6 photoreceptor cells might cause apoptosis. The DREF-induced rough eye phenotype was suppressed by a half-dose reduction of the E2F gene, one of the genes regulated by DREF, indicating that the DREF overexpression phenotype is useful to screen for modifiers of DREF activity. Among Polycomb/trithorax group genes, we found that a half-dose reduction of some of the trithorax group genes involved in determining chromatin structure or chromatin remodeling (brahma, moira, and osa) significantly suppressed and that reduction of Distal-less enhanced the DREF-induced rough eye phenotype. The results suggest a possibility that DREF activity might be regulated by protein complexes that play a role in modulating chromatin structure. Genetic crosses of transgenic flies expressing DREF to a collection of Drosophila deficiency stocks allowed us to identify several genomic regions, deletions of which caused enhancement or suppression of the DREF-induced rough eye phenotype. These deletions should be useful to identify novel targets of DREF and its positive or negative regulators.

Novel cell immobilization method utilizing centrifugal force to achieve high-density hepatocyte culture in porous scaffold

Cell seeding is one of the key procedures in the construction of tissue-engineered organs. In our previous efforts to create a bioartificial liver, high-density cultures of hepatocytes (>1 x 10(7) cells/1 cm(3)-substrate) and long-term maintenance of metabolic function were achieved with a packed-bed reactor utilizing porous poly(vinyl formal) (PVF) resin as a scaffold. However, a low seeding efficiency of about 30% remains a major obstacle to the scaleup of the reactor. In the present study, a new cell seeding method, centrifugal cell immobilization (CCI), which is based on alternating centrifugation and resuspension, was used to achieve high-density seeding and improve the seeding efficiency. Using the CCI method, the maximum density of the immobilized hepatocytes reached 3.8 x 10(7) cells/1 cm(3)-PVF, and the seeding efficiency was improved to about 43% after a relatively short immobilization process (about 15 min). Moreover, further improvement of the seeding efficiency was obtained by serial immobilization procedures. Thus, we concluded that this method is useful and effective for seeding cells into 3-dimensional scaffolds.

Somatosensory nociceptive mechanical stimulation modulates systemic and mesenteric microvascular hemodynamics in anesthetized rats

The effects of somatosensory nociceptive pinch stimulation of the hindpaw on mesenteric microvascular hemodynamics and systemic circulatory parameters were investigated in anesthetized rats using an intravital microscope-television system. Blood flow velocity in the terminal (18-40 microm in diameter) or precapillary (10-20 microm in diameter) arterioles of the mesentery was monitored by the dual sensor method developed by the authors. In the proximal terminal arterioles, blood flow velocity decreased substantially along with arteriolar constriction induced by pinching of the hindpaw for 30 s. In the distal terminal arterioles and precapillary arterioles, blood flow velocity increased after pinching. In the proximal terminal arterioles, the decrease of velocity in response to reflex vasoconstriction was abolished by intravenous injection of an alpha-blocker (phentolamine, 10 mg/kg). The increase in mesenteric precapillary arteriolar blood flow velocity (43+/-9%, p < 0.01) associated with the increase in mean arterial pressure (MAP) (22+/-1%, p < 0.01) was observed within a few seconds after the onset of the stimulation, and then the response in blood flow velocity returned to the baseline ahead of MAP response recovery after the end of the stimulus. These responses were diminished by alpha-adrenergic receptor blockade. The heart rate (HR) increase (4+/-1%, p < 0.01) induced by pinching was abolished by beta-adrenergicreceptor blockade (propranolol, 3 mg/kg, i.v.). There was a strong correlation between the increase in MAP and the decrease in renal blood flow measured by laser Doppler flowmeter (r = 0.87-0.98). Pinch stimulation of the rat hindpaw evoked changes in mesenteric arteriolar blood flow velocity that were mediated via the somato-sympathetic reflex vasoconstriction and the pressor response.

The effects of 30% and 60% xenon inhalation on pial vessel diameter and intracranial pressure in rabbits

Xenon may increase cerebral blood flow and intracranial pressure (ICP). To evaluate the effects of xenon on brain circulation, we measured pial vessel diameter changes, CO(2) reactivity, and ICP during xenon inhalation in rabbits. Minimum alveolar anesthetic concentration (MAC) for xenon was established in rabbits (n = 6). By using a cranial window model, pial vessel diameters were measured at 30% and 60% xenon inhalation and in time control groups (n = 15). ICP, mean arterial blood pressure, and heart rate were recorded during 30% and 60% xenon inhalation (n = 5). Pial vessel diameters were measured during hypocapnia and hypercapnia conditions in 60% Xenon and Control groups (n = 14). MAC for xenon was 85%. Xenon (0.35 and 0.7 MAC) dilated the arterioles (10% and 18%, respectively) and venules (2% and 4%, respectively) (P < 0.05). Dilation of arterioles was more prominent than that of venules. ICP, mean arterial blood pressure, and heart rate did not change during xenon inhalation. No difference in CO(2) reactivity was observed between Xenon and Control groups (P = 0.79). Sixty percent xenon (0.7 MAC) dilated brain vessels, but venule changes were small. Xenon did not increase ICP and preserved CO(2) reactivity of the brain vessels.

IMPLICATIONS

Xenon might increase cerebral blood flow; however, 0.7 minimum alveolar anesthetic concentration xenon preserved both low intracranial pressure and CO(2) reactivity of the cerebral vessels in the normal rabbit.

Vascular endothelial growth factor (VEGF) expression regulates angiogenesis accompanying tumor growth in a peritoneal disseminated tumor model

Quantitative analysis of the process of tumor angiogenesis was performed in a new animal model of tumor microcirculation, in which colon carcinoma cells were inoculated into the peritoneal cavity of rats. Time-dependent changes in the microvascular architecture of mesenteric microvessels of tumor-bearing rats were visualized using an intravital microscope. Simultaneously, the expression of vascular endothelial growth factor (VEGF) by the tumor cells and VEGF secretion into ascites were analyzed. The results showed that VEGF increases microvascular permeability and stimulates the growth of microvessels into the tumor and that the spatial and temporal concentration of VEGF is strongly correlated. Such a correlation was stronger in the early angiogenic stages of tumor growth than in the subsequently occurring multiple metastatic stage, when VEGF was still observed at a high level in tumor surroundings. Thus, VEGF is suggested to be primarily involved in the pathophysiological control of angiogenesis accompanying tumor progression.

Effects of intra-arterial administration of prostaglandin E1 on rat cremaster muscle microcirculation

In plastic and reconstructive surgery, postoperative drug therapy with prostaglandin E1 (PGE1) has been widely used to prevent flap necrosis and to extend flap surviving area. In the present study, we assessed the effects of intra-arterial administration of PGE1 on microcirculation. The left cremaster muscle of male Wistar rats were used to measure microcirculatory hemodynamic parameters. The values of internal vessel diameter and erythrocyte velocity were measured by using the confocal laser-scanning microscope (CLSM) system and fluorescent dyes. The blood flow rate was calculated from measured internal vessel diameter and erythrocyte velocity. Internal vessel diameter and flowing erythrocytes were satisfactorily visualized by using the CLSM system. The blood flow rate of arteriole, venule and capillary were dose dependently increased by the intra-arterial administration of PGE1 from the minimum dose of 0.01 ng/kg/min. It is suggested that the intra-arterial administration of PGE1 is a more effective way of postoperative drug therapy than intravenous injection for flap surgery.

Improvement of metabolic performance of cultured hepatocytes by high oxygen tension in the atmosphere

Maintaining metabolic functions of cultured hepatocytes at higher levels is an essential requirement for the development of a bioartificial liver. We investigated the effect of oxygen tension (10--40%) of the medium on immobilization efficiency and metabolic functions of cultured hepatocytes obtained from a rat for up to 4 days. Immobilization efficiencies of cultures in 10% oxygen showed a significantly lower value from those for the other conditions. The ammonium metabolic rate and the albumin secretion rate were significantly improved with an increase of dissolved oxygen tension for up to 2 days. These values remained similar in the later stage of the culture. The urea secretion rate showed similar values in all conditions. In conclusion, higher oxygen tension improved immobilization efficiency and metabolic functions of cultured rat hepatocytes in the earlier stage of culture for up to 2 days.

Insulin increases blood flow rate in the microvasculature of cremaster muscle of the anesthetized rats

The hemodynamic actions of insulin in skeletal muscle microvasculature are not yet well elucidated. In the present study, we investigated the effects of systemic insulin injection on arteriole and capillary diameter and blood flow rate in rat cremaster muscle, using intravital real-time confocal laser-scanning microscope system in combination with selective fluorescent labeling. Subcutaneous insulin injecbon (1 U/kg) significantly increased serum insulin levels at 15 minutes as compared with saline injection. At 15 and 30 minutes after insulin injection, blood glucose levels were significantly lower compared to saline injected controls. Arteriolar diameter was significantly increased at 15 and 30 minutes by insulin. Arteriolar erythrocyte flow velocity was significantly increased at 15 and 30 minutes. In addition, capillary erythrocyte flow velocity was increased at 15 and 30 minutes. These results demonstrated that calculated blood flow rates in capillary and arteriole increased after insulin injection.

Effect of shear stress on platelet adhesion to expanded polytetrafluoroethylene, a silicone sheet, and an endothelial cell monolayer

We visualized in real-time platelets adhering to the surface of three representative biomaterials, by using an apparatus consisting of a modified cone and plate rheometer combined with an upright epifluorescence microscope under two shear flows (0.1 and 5.0 dyne/cm2). The materials were expanded polytetrafluoroethylene (ePTFE), silicone sheet, and a monolayer of bovine endothelial cells (ECs) formed on glass, all of which are opaque materials used for artificial blood vessels and medical devices. According to quantitative analysis, the monolayer of ECs formed on glass had better blood compatibility than did either the ePTFE or the silicone sheet under shear flow conditions. Under a shear flow condition of 0.1 dyne/cm2, platelet adhesion was silicone sheet > ePTFE. In contrast, under a shear flow condition of 5.0 dyne/cm2, ePTFE > silicone sheet. These results indicate that the intensity of shear stress could modify the order of hemocompatibility of the materials. Therefore, direct observation of platelet adhesion under shear flow conditions is indispensable for testing and screening biomaterials and for providing a precise quantitative evaluation of platelet adhesion.

New type of matrix support for bone marrow cell cultures: in vitro culture and in vivo transplantation experiments

A new type of bone marrow cell culture system was developed by using a highly porous substrate matrix, i.e., porous polyvinyl formal (PVF) resin. Murine bone marrow (BM) cells were cultured without the use of exogenous growth factors in a three-dimensional matrix support made of collagen coated porous PVF resin. To examine the optimal conditions for highest stromal cell density, short-term and long-term in vitro culture experiments using PVF were performed. In the short-term culture experiments, it was found that cubes of PVF (10 x 10 x 2 mm and 130 microm in pore size) coated with type I collagen with a seeding density of 2x10(7) BM cells offered the most appropriate culture conditions. In the long-term cultures, BM cells in PVF maintained their viability for up to 6 weeks. In another series of re-inoculation experiments, freshly isolated BM cells were inoculated onto the already developed stromal layer. In this study, a higher cell density of the stromal layer was obtained in the PVF culture compared with those in the control dish culture. Based upon the results of in vitro experiments, in vivo transplantation studies were also performed. Histologic examinations of the subcutaneously transplanted PVF with stroma revealed host derived hematopoiesis inside the PVF matrix. Moreover, survival of approximately 15% of the transplanted BM cells that were cultured in PVF were confirmed in X-ray irradiated recipients. From these results, it is suggested that PVF resin is a promising three-dimensional substrate for BM cell culture and that it can maintain hematopoietic stem cells or progenitor cells after transplantation.

[Coronary arterial revascularization in dialysis patients]

It is recently reported that among chronic renal dialysis patients myocardial infarction accounts 7.4% of all the cause of death in Japan. In order to improve the mortality of dialysis patients the treatment of ischemic heart disease (IHD) is a major problem. We review previous reports and discuss about the treatment of IHD in dialysis patients. The collected data from the previous reports written about CABG in dialysis patients shows that the mortality of CABG is 7.8% (30/387), the probability of perioperative myocardial infarction (PMI) 8.6% (21/243), brain infarction 1.6% (4/243) and major infection 5.8% (14/243). 3-year and 5-year mortality rate after CABG is reported to be 69-80% and 48-56%, respectively. The result of CABG is excellent and shows that this procedure improves the mortality of dialysis patients with IHD. The procedural mortality of PTCA is 5.6% (8/143), the probability of PMI is 7% (10/143). Many reports shows the high probability of the recurrence of chest pain (60-86%). This procedure when performed in dialysis patients is incomplete because of the calcification of the coronary artery. Even among the dialysis patients it is preferable to perform CABG positively.

Relationships between age of onset, antisocial history and general psychopathological traits in Japanese alcoholics

This study investigated the relationships of age of onset, antisocial history and general psychopathological traits measured by the Minnesota Multiphasic Personality Inventory (MMPI) in Japanese alcoholics (n = 84). A 2 (earlier vs later onset) x 2 (antisocial vs non-antisocial) multivariate analysis of covariance showed that age of onset had a significant correlation with some subscales of the MMPI such as L (lie), Sc (schizophrenia), and Si (social introversion), whereas history of antisocial behavior had no significant correlation with any MMPI clinical subscales. This result indicated that age of onset was a more significant variable than was antisocial history with regard to the current general psychopathological traits on MMPI in Japanese alcoholics.

Long-term culture of fetal liver cells using a three-dimensional porous polymer substrate

To develop a bioartificial liver, long-term culture of fetal liver cells over a month's time was performed under three different culture conditions, i.e., stationary cultures and shaken-flask cultures, both by using a substratum made of porous polyvinyl formal (PVF) resin and conventional monolayer dish cultures as controls. Time course changes in cell numbers and albumin secretion were evaluated in cultures using Williams' E medium (WE) or minimum essential medium alpha (aMEM) supplemented with serum and hormones. In the WE medium, the numbers of fetal liver cells in all culture conditions gradually decreased with time, and albumin secretion rates rapidly decreased. In the stationary cultures using PVF, however, a significant increase in albumin secretion was observed after two weeks of culture. When cells were cultured in aMEM, the fetal liver cells exhibited sufficient proliferation in stationary and monolayer cultures, although albumin secretion rates per single cell were lower than those in WE. On the basis of these results, another series of culture experiments were performed, in which aMEM was used for the first 10 days to encourage cell proliferation, and the medium was changed to WE afterward. In these cultures, albumin secretion rates in the stationary cultures dramatically increased after the medium exchanges and were maintained at these high levels throughout the remaining culture period.

A new model of lung metastasis for intravital studies

We created anexperimental model of pulmonary metastasis based on subcutaneously implanted Lewis lung cancer in mice and observed in vivo the microcirculation of spontaneously metastasized tumors in the lung. The mice lung was held by a small handmade suction ring to stop cardiac and respiratory movement. Using fluorescent microscopy, tumor microcirculation and normal lung microcirculation in the same lung lobe were compared by measuring microvessel diameter and blood flow velocity [red blood cell (rbc) velocity]. In normal microcirculation, the mean values of microvessel diameter and rbc velocity were 10.4 +/- 2.7 microm and 188 +/- 63 microm/s, respectively. In tumor microcirculation, the mean values of the same were 10.6 +/- 3.3 microm and 105 +/- 40 microm/s. The rbc velocity in normal microcirculation was significantly higher (P < 0.001) than that in tumor microcirculation. The calculated shear rates of normal microcirculation and tumor microcirculation were 73.4 +/- 23.4 (/s) and 41.2 +/- 16.1 (/s), respectively. The shear rate of the tumor microcirculation was significantly slower (P < 0.001) than that of the normal microcirculation. We demonstrated a feasibility of observation and measurement of tumor microcirculation in the lung and confirmed that the physiologic data were compatible to those in the brain or in the liver reported by others. This model might be useful for studying metastatic tumor pathophysiology in the lung microcirculation.

Safety and efficacy of blood donation prior to elective cardiac surgery in anemic patients

OBJECTIVE

To determine the safety and effectiveness of blood donation in anemic patients, we harvested blood from cardiac patients with baseline hemoglobin levels below 11.0 g/dl.

METHODS

Subjects were 118 patients who underwent elective cardiac surgery between January 1994 and October 1997. We assigned patients to 1 of 2 groups based on their entry hemoglobin level: an anemic group (hemoglobin < 11.0 g/dl, n = 20) and a nonanemic group (hemoglobin > or = 11.0 g/dl, n = 98). All patients received subcutaneous administration of recombinant human erythropoietin, and autologous blood was collected once a week for at least 3 weeks before the scheduled surgery date if the hemoglobin level exceeded 10.5 g/dl.

RESULTS

No statistically significant differences were seen between the 2 groups in patient profiles or surgical data. The estimated hemoglobin increase did not differ significantly between groups at any time point. The total collected blood volume per patient was greater in the nonanemic group than in the anemic group (1098 +/- 224 ml vs. 712 +/- 334 ml), but the difference in volume was not statistically significant. The percentage of patients who received allogeneic blood did not differ significantly between groups. No side effects were associated with hemoglobin level prior to donation because the incidence of side effects was similar across hemoglobin levels.

CONCLUSIONS

This study suggests that autologous blood donation reduces the need for allogeneic blood in patients with baseline hemoglobin levels below 11.0 g/dl.

Autologous blood donation with recombinant human erythropoietin in anemic patients

BACKGROUND

Various blood management strategies can be used to reduce the need for allogeneic blood in cardiac surgery. In anemic patients, however, avoidance of allogeneic blood transfusion is difficult to achieve. This study was performed to assess the safety and effectiveness of preoperative blood collection using recombinant human erythropoietin (rHuEPO) for reducing the exposure to allogeneic blood in anemic patients.

METHODS

Thirty-two anemic patients undergoing cardiac surgery at our hospital between January 1994 and October 1997 were divided into two groups according to preoperative strategies: 3-week treatment with rHuEPO and blood donation (group 1, n = 16) or iron supplementation alone (group 2, n = 16).

RESULTS

There were no statistically significant differences between the two groups in patients' characteristics and surgical data. The number of reticulocytes was increased at just before surgery in group 1, whereas group 2 showed no significant increase. The estimated hemoglobin increases in group 1 were higher at 7 days and just before surgery. The mean number of required allogeneic blood for patients during surgery was 0.59 +/- 1.12 U in group 1 and 5.01 +/- 2.63 U in group 2. In 75% of group 1 patients, allogeneic blood transfusion was successfully avoided, whereas all patients in group 2 received allogeneic blood.

CONCLUSIONS

This study suggests that the combination of rHuEPO administration and autologous blood donation can reduce the need for allogeneic blood in anemic patients.

Novel polymorphism of the 5-lipoxygenase activating protein (FLAP) promoter gene associated with asthma

The human 5-lipoxygenase activating protein (FLAP) gene is one of the key genes involved in the production of the cysteinyl-leukotrienes. We studied novel polymorphism of the FLAP promoter gene and attempted to clarify the relationship between this polymorphism and asthma. We sequenced the FLAP promoter region, containing the -170 to +46-bp sequence from the translational start codon, and found two homozygotes of novel alleles in the polyadenyl region which showed 21 A repeats and 18 A repeats, respectively. The frequency of the 21 A repeats was 52/71 (73.2%) in asthmatics and 39/71 (54.9%) in control subjects. The difference between these frequencies was statistically significant (P = 0.035). This is the first report of FLAP promoter gene polymorphism associated with asthma. Our data suggest that FLAP promoter gene polymorphism might play a crucial role in the pathogenesis of asthma.

Real time observation of platelet adhesion to opaque biomaterial surfaces under shear flow conditions

We developed a new system which enables direct observation of platelet adhesion on opaque biomaterials under shear flow conditions, by combining a thin quartz cone which produces laminar shear flows, with an upright epifluorescence microscope which visualizes stained platelets through the rotating cone. This is the first report on the observation of platelets adhered to opaque biomaterials in real time under shear flow conditions. The direct observation of platelet adhesion to expanded polytetrafluoroethylene (ePTFE) as an opaque biomaterial revealed that the kinetics of platelet adhesion to ePTFE depended greatly on shear stresses, showing that the shear stress of 5.0 dyne/cm2 induced higher adhesiveness of platelets to ePTFE than that of either 0.1 or 15 dyne/cm2. The observation also showed a difference in platelet adhesiveness among ePTFEs with different fibril lengths--0, 3.2, 18, and 35 microm--indicating that ePTFEs with shorter fibril length had lower adhesiveness of platelets under a shear stress of 5.0 dyne/cm2. It is indispensable for analyzing the phenomena of platelet adhesion to opaque biomaterials to observe in real-time rolling, adhesion, and detachment of platelets under shear stresses without disturbing shear flow conditions. The results showed that the mechanical and optical design of the system could serve this purpose.

Isolation of cDNAs encoding cellular drug-binding proteins using a novel expression cloning procedure: drug-western

A rapid and convenient new method for isolating the genes encoding cellular drug-binding proteins is described. This method, drug-western, is based on the use of the drug conjugated with a marker molecule as a probe for the screening of a cDNA library. Unlike the other methods, this method allows us to identify the genes for trace amounts of cellular drug-binding proteins without purification. We have used this approach to isolate human cDNA clones encoding binding proteins of HMN-154 ((E)-4-[2-[2-(p-methoxy-benzene-sulfonamide) phenyl]ethenyl] pyridine), a novel benzenesulfonamide anticancer compound (Katoh and Hidaka 1997). The proteins encoded by two of the isolated clones are identical to NF-YB, B subunit of nuclear transcription factor NF-Y, and thymosin beta-10, respectively. Recombinants of both proteins bind specifically to HMN-154 in vitro. Comparison of amino acid sequences between these proteins shows the sequence similarity in a short amino acid stretch [K(X)AKXXK]. Deletion or mutation of this region causes the significant loss of binding of both proteins to HMN-154. Furthermore, HMN-154 inhibits DNA binding of NF-Y to the human major histocompatibility complex class II human leukocyte antigen DRA Y-box sequence in a dose-dependent manner. Interestingly, other binding proteins identified by this method also possess the same or a similar motif. These results clearly demonstrate that NF-YB and thymosin beta-10 are specific cellular binding proteins of HMN-154 and that this shared region is necessary for the binding to HMN-154. Hence, this new method is thought to be useful for the identification of drug-binding proteins.

Blood flow and leukocyte adhesiveness are reduced in the microcirculation of a peritoneal disseminated colon carcinoma

Dynamic behavior of leukocytes in the microcirculation of solid tumor tissue was visualized using a fluorescent labeling technique combined with the use of a real-time confocal laser-scanning microscope (CLSM) system. Colon tumor cells (RCN-9) were inoculated into the peritoneal cavity of male Fischer 344 rats. Tumor-free rats were similarly injected with physiological saline (intraperitoneally). Ten days after tumor inoculation, the mesentery was exteriorized and subjected to vital microscopic observation under the CLSM system. Leukocytes were labeled with rhodamine 6G (100 microg kg(-1), intravenously), and their behavior within the microvessels (10-30 microm in diameter) was analyzed both in the solid tumor tissues and the normal mesentery. Wall shear rate was calculated from the measured values of vessel diameter and erythrocyte flow velocity. In tumor microvasculature of tumor-bearing rats, the centerline erythrocyte velocity (0.73 +/- 0.58 mm s(-1), mean +/- standard deviation) and wall shear rate (210 +/- 151 s(-1)) were significantly lower than those of the tumor-free rats (1.27 +/- 0.83 mm s(-1), 344 +/- 236 s(-1), respectively). Despite such reduced flow conditions, flux of the rolling leukocytes as well as density of the adhered leukocytes both decreased significantly in tumor microvasculature as compared with normal controls. The methods developed in this work show promise in improving our understanding of tumor biology and pathophysiology.

Improvement of metabolic performance of hepatocytes cultured in vitro in a packed-bed reactor for use as a bioartificial liver

A packed-bed reactor using reticulated polyvinyl formal (PVF) resin as a support material is a useful configuration to achieve high density culture of hepatocytes for use as a bioartificial liver. The authors investigated the effects of oxygen concentrations of the culture medium on the metabolic performance of hepatocytes cultured in the reactor. A packed-bed reactor loaded with 250 PVF resin cubes (2 x 2 x 2 mm) was used. Hepatocytes obtained from male Wistar rats were inoculated into the reactor. Culture medium was perfused from the reservoir into the reactor through an oxygenator using a roller pump. Concentration of the dissolved oxygen in the medium was controlled by changing the gas mixture ratio supplied to the oxygenator. Hepatocytes cultured in the packed-bed reactor (cell density: 8.6 x 10(6) cells/cm3 PVF) under conditions of high dissolved oxygen concentrations ranging from 260 to 460 micromol/L showed 30% higher ammonium metabolic activity and 85% higher albumin secretion activity compared with those from the monolayer culture in the earlier culture stage (up to 2 days). However, low oxygen concentrations in the medium (<100 micromol/L) impaired activities of cultured hepatocytes.

Effects of shear stress on metabolic function of the co-culture system of hepatocyte/nonparenchymal cells for a bioartificial liver

To improve the culture conditions of hepatocytes for use as a bioartificial liver, the effects of shear flow on the co-culture system of hepatocytes/nonparenchymal cells (NPC) were investigated. A flow chamber with a collagen coated rectangular glass plate, where hepatocytes (5 x 10(4) cell/cm2) and NPC (2 x 10(5) cell/cm2) were seeded, was used to attain a shear stress of 4.7 dyne/cm2. Concentrations of ammonia and urea in the medium were measured daily during the 2 week experiment. The metabolic activity of hepatocytes in the homotypic culture were lower than those of the co-culture, especially when the cultivation time exceeded 1 week. In addition, the applied shear flow promoted activity of the co-culture system. An enhancement in the rates of ammonium removal and urea synthesis was obtained in the perfusion systems. Morphologic observation revealed that aggregates of hepatocytes formed abundantly in the perfusion system and hepatocytes developed a cuboid shape. This suggested that perfusion affected the function and morphology of hepatocytes in the co-culture system. Shear flow could induce cell-cell interactions and secretion of extracellular matrix through the activation of NPC.

[Autologous blood donation with recombinant human erythropoietin prior to elective cardiac surgery in anemic patients]

Despite the reducing exposure to allogeneic blood in cardiac surgery, most of patients with anemia still require allogeneic blood. In this study, we have attempted to harvest the blood from cardiac patients with baseline hemoglobin levels below 11.0 g/dl using recombinant human erythropoietin (rHuEPO). 29 anemic patients undergoing cardiac surgery at our hospital between January 1994 and March 1997 were divided into two groups: 3 weeks' treatment with recombinant human erythropoietin (rHuEPO) and blood donation (group 1, n = 15) and iron supplementation alone (group 2, n = 14). There were no statistically significant differences among the two groups in patients characteristic and surgical data. No serious adverse events after phlebotomy were apparent in patients donating autologous blood. Patients in group 1 had significantly higher hemoglobin levels than patients in group 2 at 7 days before operation. The number of reticulocytes were increased at just before operation in group 1, whereas group 2 showed no significant increase. The estimated hemoglobin increase in group 1 were higher at 7 days and just before operation. In 75% of group 1, allogeneic blood transfusion could be avoided, while all patients in group 2 received allogeneic blood transfusion. This study suggests that the combination of rHuEPO administration and autologous blood donation would be beneficial for anemic patients in elective cardiac surgery. The use of rHuEPO should not be restricted to anemic patients.

The characteristics of endothelin receptor subtypes on muscle contraction and neuro-transmission in rat vas deferens

We observed endothelin (ET)-induced contractile responses on prostatic and epididymal segments, as well as the facilitation of an electrically stimulated tone on prostatic segments of isolated rat vas deferens. In both segments, the selective ET(B)-receptor agonists, IRL 1620 and sarafotoxin S6c, produced only a small contraction or no contraction at a concentration of 1 microM. The rank order of contraction potencies (pD2 value) was ET-1 = ET-2 > ET-3 >> sarafotoxin S6c = IRL 1620. The maximum responses of ET-induced contractions in the prostatic segments were larger than those in the epididymal segments. The contractile response to ET-3 was antagonized by pretreatment for 30 min with BQ-123 (10 nM), a selective ET(A) receptor antagonist, and BQ-788 (1 microM), a selective ET(B) receptor antagonist. The contractile responses to ET-1 were antagonized by pretreatment with BQ-123 (10 microM), but not with BQ-788 (1 microM). The ET-3-induced facilitation on the twitch response to electrical stimulation in the prostatic segment of the vas deferens was antagonized by BQ-123 (0.1 microM) and BQ-788 (1 microM). The ET-1-induced facilitation was antagonized by pretreatment with BQ-123 (3 microM), but not with BQ-788 (10 microM). These results suggest that in rat vas deferens the ET(A) receptors are divided into BQ-123-sensitive ET(A1) and BQ-123-insensitive ET(A2) subtypes, and the production of a contractile response of smooth muscle as well as the facilitation of neurotransmission are accomplished through mediation by ET(A1)- and ET(A2)-subtypes.

Hepatocyte culture utilizing porous polyvinyl formal resin maintains long-term stable albumin secretion activity

To investigate the effects of culture conditions on the maintenance of metabolic functions of cultured hepatocytes, long-term hepatocyte culture lasting 20 days was performed under two different culture conditions, i.e. stationary cultures utilizing porous polymer (polyvinyl formal (PVF) resin) as a substratum and conventional monolayer dish cultures without PVF. Metabolic activities specific to hepatocytes were evaluated in terms of ammonia metabolism, urea synthesis, and albumin secretion. Concerning ammonia metabolic and urea synthetic activities, no significant differences in maintenance of these activities were found between the two culture conditions, and these activities rapidly decreased with the elapse of the culture period, especially during the early stage of the experiments. However, after day 10, these activities in the stationary cultures were maintained at a slightly more favorable level than in the monolayer cultures. On the other hand, compared with ammonia metabolism and urea synthesis, stable and well-maintained albumin secretion of hepatocytes (60% of the activity in day 1) was exhibited in the stationary culture experiments, despite that this particular activity under the monolayer culture condition gradually reduced to a very low level (5.7% of that on day 1) at the end of the culture. From the morphological observations, hepatocytes immobilized in the PVF resin revealed individual spherical shapes without forming multicellular aggregation, and it was suggested that this characteristic structure contributed to good albumin secretion of hepatocytes. In conclusion, the advantages of the hepatocyte culture technique utilizing PVF resin over the conventional dish culture in maintaining some representative metabolic function specific to hepatocytes were clarified.

[A case of progressive right coronary ostial stenosis after Carrel patch method using gelatin-resorcin-formalin glue]

A 31-year-old man with type A chronic aortic dissection associated with annuloaortic ectasia underwent the concomitant graft replacement of the total aortic root and the transverse aortic arch. The two coronary arteries were reconstructed using the Carrel patch method. The false lumen of right coronary artery was closed by injection of GRF glue into the dissected space and compressing the dissected layers. Postoperative course was uneventful, and the patient has returned to normal daily life 2 months after surgery. Remarkable progression of the right coronary artery ostial stenosis was observed by coronary angiography 6 months after surgery. The remarkable progression of stenosis may occur in association with injection of GRF glue into the dissected space, although the exact etiology of the progressive stenosis remains obscure.

[The comparison of tepid and moderate hypothermic cardiopulmonary bypass in cardiac surgery]

Normothermic cardiopulmonary bypass (CPB) is being increasingly used at some institutions. Patients undergoing normothermic CPB have a higher systemic oxygen demand and may be at higher risk for ischemic injury. This study was designed to confirm the clinical efficacy and safety of tepid hypothermic CPB. Thirty-six patients undergoing open heart surgery between June 1993 and August 1994 were divided into two groups: tepid (n = 18, 32 degrees C) and moderate (n = 18, 26 degrees C) hypothermic CPB. There were no significant differences in preoperative and perioperative patients characteristics between the two groups. The mean aortic cross-clamp time did not differ between two groups, but the mean CPB time was significantly shorter in tepid hypothermic patients. Serum lactate after CPB and lactate/pyrvate ratio during CPB in tepid hypothermic patients were significantly lower than in moderate hypothermic patients. The mixed venous oxygen saturation in tepid hypothermic patients was significantly lower however, it was maintained at levels more than 70% during CPB. This study suggests that tepid hypothermic CPB is a safe and effective alternative to moderate hypothermic CPB for patients undergoing open heart surgery. Previous reports have documented that patients undergoing normothermic CPB are at greater risk for cerebral desaturation. We should evaluate cerebral venous oxygen saturation during tepid hypothermic CPB before the induction of normothermic CPB.

Packed-bed type reactor to attain high density culture of hepatocytes for use as a bioartificial liver

In an attempt to develop a bioartificial liver using cultured hepatocytes, we investigated the short-term and long-term viability and metabolic functions of hepatocytes cultured in a new type of packed-bed type reactor using reticulated polyvinyl formal (PVF) resin as a supporting material. Perfusion culture experiments using this reactor, as well as monolayer cultures using conventional collagen-coated Petri dishes as control experiments, were performed. It was found that the highest density of immobilized hepatocytes attained with PVF resin was on the order of 10(7) cells/cm3 PVF and that hepatocytes cultured in this type of module for up to a week showed a sufficient level of liver-specific metabolic functions, such as ammonium metabolism, urea-N synthesis, and albumin secretion, to be comparable to those in the monolayer culture. It is concluded that the packed-bed reactor system utilizing PVF resin is a promising means to develop a bioartificial organ using hepatocytes.

Dietary effect of a symmetrical triacylglycerol, 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol, on fatty acid composition of guinea pigs

The dietary effect of 1,3-biseicosapentaenoyl-2-gamma-linolenoyl glycerol (STG) on the fatty acid composition of guinea pigs was examined and compared with that of an eicosapentaenoic acid ethyl ester (EPA-E) and of a soybean oil (SBO) diet. In terms of content of plasma lipid, EPA-E had a greater hypolipidemic effect than STG. On the other hand, in terms of EPA incorporation, contents of EPA in liver lipid were almost the same in the STG and EPA-E groups. Considering that the amount of EPA administered in the EPA-E group was almost 1.5 times that of the STG group, EPA may be absorbed more effectively as the glycerol ester than as the ethyl ester in guinea pigs. In all the tissue lipids, the STG group had a higher unsaturation index (UI) than the EPA-E group even though there is a lower UI in the STG diet than the EPA-E diet. These results suggest that greater amounts of desaturase products as a whole were synthesized in the STG group than in the other two groups. The dihomo-gamma-linolenic acid/arachidonic acid (DGLA/AA) ratio in plasma total lipids in the STG group was 3.5 times that of SBO group, and the DGLA/AA ratio in the EPA-E group was half that of the SBO group. In liver lipid, the ratios of DGLA/AA and EPA/AA in the STG group were 0.687 and 0.488 (phosphatidylcholine fraction) and 0.237 and 0.752 (phosphatidylethanolamine fraction), respectively. The ratio of DGLA/AA as well as the high EPA/AA ratio obtained in the present study with the STG diet may lead to physiological alterations, including enhanced synthesis of 1- and 3-series eicosanoids.

[A case of primary anterior mediastinal liposarcoma with a heterotopic mass in the pericardium of the same histology]

We experienced a case of primary anterior mediastinal liposarcoma with a heterotopic mass in the pericardium of same histology. Twenty reported cases in Japan were also studied. The patient was a 50-year-old male who visited the hospital because of an abnormal shadow on a chest X-ray. The diagnosis of anterior mediastinal tumor was confirmed by a chest CT. The patient underwent a complete resection of the mediastinal and intrapericardial masses. The histologic diagnosis was a well differentiated liposarcoma of Enzinger's classification. No evidence of recurrence or metastasis was detected in the third postoperative year. Liposarcoma is rarely seen in the mediastinum. Since radiotherapy and chemotherapy are ineffective therapeutic modalities, surgery would be the treatment of choice and complete surgical resection is mandatory.

[Application of extracorporeal membrane oxygenation for respiratory failure following septic pulmonary emboli]

A 23-year-old man, diagnosed as ventricular septal defect in childhood, was hospitalized with right-sided infective endocarditis. He developed acute respiratory failure following septic pulmonary emboli and underwent urgent surgical treatment, because vigorous medical treatment was ineffective. Extracorporeal membrane oxygenation was performed to maintain arterial blood oxygen tension after cardiopulmonary bypass and the patient was weaned from ECMO after 36 hours. Postoperatively, mechanical ventilation for respiratory failure was needed continuously and pleural leaks due to lung injuries were increased. The reduction of pleural leaks by surgical closure of fistula and plication of the cyst decreased gas exchange impairment. To our knowledge, application of extracorporeal membrane oxygenation for septic pulmonary emboli is unprecedented.

Synergistic effect of aurintricarboxylic acid and triflavin in a photochemically induced thrombosis model in rats

We report here the synergistic antithrombotic effect of aurintricarboxylic acid in combination with a snake venom-derived disintegrin, triflavin, in a photochemically induced thrombosis model in rats. The time to initiation of thrombus was prolonged by i.v. bolus injection of aurintricarboxylic acid at 10 mg/kg. In contrast, time to occlusion was dose-dependently prolonged by both agents, this prolongation being significant with aurintricarboxylic acid at 10 mg/kg i.v. and with triflavin at more than 3 mg/kg i.v. Interestingly, the combination of aurintricarboxylic acid at 3 mg/kg i.v. and triflavin at 1 mg/kg i.v. prolonged not only the initiation of thrombus, but also the time to occlusion.

Long-term performance of albumin secretion of hepatocytes cultured in a packed-bed reactor utilizing porous resin

A packed-bed reactor utilizing the porous polymer, polyvinyl formal (PVF) resin, as a supporting material was applied for the long-term culture of rat hepatocytes. Perfusion cultures using this reactor, as well as monolayer cultures, were performed for up to 1 week under 3 different media conditions. When serum-free or epidermal growth factor-containing medium was used, albumin secretion rates showed constant decreases in both the perfusion and the monolayer cultures, and approximately 10% of the activity exhibited on Day 1 was preserved at the end of the cultures. In contrast, the hepatocytes supplemented with serum-containing medium exhibited stable ability of albumin secretion throughout the culture period under the perfusion culture condition using PVF resin. From the microscopic observation, the immobilized hepatocytes in this medium revealed round shapes, and a cluster of cell aggregates was scarcely seen.

Antiplatelet and antithrombotic effects of YM337, the Fab fragment of a humanized anti-GPIIb/IIIa monoclonal antibody in monkeys

The antiplatelet and antithrombotic effects of the Fab fragment of the humanized antiplatelet glycoprotein (GP) IIb/IIIa monoclonal antibody C4G1 (YM337) were investigated in monkeys. First, the relationship between the inhibition of platelet aggregation and the prolongation of bleeding time was studied in rhesus monkeys. YM337 dose-dependently inhibited ex vivo platelet aggregation, with complete inhibition at doses higher than 0.25 mg/kg intravenous injection or 1.5 micrograms/kg/min infusion. At 0.25 mg/kg bolus injection followed by 1.5 micrograms/kg/min infusion, YM337 immediately and continuously inhibited platelet aggregation during the 6-h infusion period with platelet aggregation rapidly returning to over 50% of baseline within 1 h after the cessation of infusion. Template-bleeding time was significantly prolonged during the period of complete inhibition of platelet aggregation. Second, the antithrombotic effects of YM337 were investigated in a photochemically-induced thrombosis model in squirrel monkeys. YM337 at a dose of 1 mg/kg intravenous injection followed by 6 micrograms/kg/min infusion for 60 min prevented occlusive thrombus formation in all 4 monkeys. In contrast, time to occlusive thrombus formation did not change on intravenous bolus injection of aspirin 17 mg/kg (11.3 +/- 5.2 min) or sodium ozagrel (9.4 +/- 3.0 min) compared with saline (13.3 +/- 4.0 min). YM337 but not aspirin or sodium ozagrel significantly inhibited ex vivo ADP-induced platelet aggregation, while all drugs completely inhibited arachidonic acid-induced platelet aggregation. However, while aspirin and sodium ozagrel inhibited the thromboxane B2 generation accompanying arachidonic acid-induced platelet aggregation, YM337 had no effect on this variable. Platelet counts and bleeding time showed no significant change in any group in this squirrel monkey model. These results indicate that YM337, with a short half-life, may be a useful therapeutic agent in patients with thrombotic disorders.

Viscoelastic properties of cultured porcine aortic endothelial cells exposed to shear stress

The viscoelastic properties of cultured endothelial cells exposed to shear stress were measured by the micropipette technique and analyzed using a standard linear viscoelastic model. Cells from porcine aorta were cultured on glass coverslips. A shear stress of 2 Pa was applied using a parallel-plate flow chamber. After flow exposure, the cells were detached from the coverslips and suspended in culture medium. The micropipette experiment was performed on single cells under an inverted microscope. The desired negative pressure was applied stepwise to the tip of the micropipette by opening a solenoid valve. The deformation process of cells in the micropipette was observed through a TV camera and recorded on a videotape. To obtain the viscoelastic parameters, a half-space model of an endothelial cell was used. The cell was assumed to be a homogeneous and incompressible material, and a standard linear viscoelastic model was employed to account for the viscoelastic response. Cells exposed to shear stress for 6 h became spherical in shape after detachment from the substrate. In the case of a 24 h exposure, about half of the detached cells retained an elongated shape upon detachment, with the others taking on a spherical shape. The elastic constants, as determined based on the model, were approximately two times higher for the elongated cells than for control cells from static culture, no-flow conditions, indicating that the elongated cells became stiffer. Enhanced viscous properties also were observed for the elongated cells. These viscoelastic properties are considered to be closely related to cytoskeletal structure. Spherical cells upon detachment, even those that had been exposed to shear stress for 24 h, did not show such significant changes in viscoelastic mechanical properties.