Development of an implantable wireless ECoG 128ch recording device for clinical brain machine interface

Brain Machine Interface (BMI) is a system that assumes user's intention by analyzing user's brain activities and control devices with the assumed intention. It is considered as one of prospective tools to enhance paralyzed patients' quality of life. In our group, we especially focus on ECoG (electro-corti-gram)-BMI, which requires surgery to place electrodes on the cortex. We try to implant all the devices within the patient's head and abdomen and to transmit the data and power wirelessly. Our device consists of 5 parts: (1) High-density multi-electrodes with a 3D shaped sheet fitting to the individual brain surface to effectively record the ECoG signals; (2) A small circuit board with two integrated circuit chips functioning 128 [ch] analogue amplifiers and A/D converters for ECoG signals; (3) A Wifi data communication & control circuit with the target PC; (4) A non-contact power supply transmitting electrical power minimum 400[mW] to the device 20[mm] away. We developed those devices, integrated them, and, investigated the performance.

Quality assurance: recommended guidelines for safe heating by capacitive-type heating technique to treat patients with metallic implants

This article is a redissemination of the previous Japanese Quality Assurance Guide guidelines. Specific absorption rate and temperature distribution were investigated with respect to various aspects including metallic implant size and shape, insertion site, insertion direction, blood flow and heating power, and simulated results were compared with adverse reactions of patients treated by radio frequency capacitive-type heating. Recommended guidelines for safe heating methods for patients with metallic implants are presented based on our findings.

A new control method depending on primary phase angle of transcutaneous energy transmission system for artificial heart

A new control method for stabilizing output voltage of the transcutaneous energy transmission system for artificial heart is proposed. This method is primary side, is outside of the body, which is not depending on a signal transmission system from the implanted device. The impedance observed from primary side changes from inductive to capacitive and the output voltage decreases drastically when the output current is large and the coupling factor is higher than that of the optimal condition. In this case, the driving frequency should be changed to higher so that the phase angle of the primary impedance is zero degree. The preliminary examination showed that this control method can enhance the output voltage limit to twice and the feasibility of the primary side control.

The possibility of muscle tissue reconstruction using shape memory alloys

Severe dysfunction of muscle tissues can be treated by transplantation but the success rate is still not high enough. One possibility instead is to replace the dysfunctional muscle with artificial muscles. This article introduces a unique approach using shape memory alloys (SMAs) to replace the anal sphincter muscle for solving the problem of fecal incontinence. The use of SMAs that exhibit a two-way shape memory effect allows the device to function like a sphincter muscle and facilitates simple design. In this article, we will give a brief introduction to the functional material-SMA-together with its medical applications, and will follow this with a description of the recent progress in research and development of an SMA-based artificial sphincter. The possibility of its commercialization will also be discussed.

Swallow stent with hyperthermia function

An operation of an esophagus cancer is one of the most difficult operations even now, when medicine progressed. One of the most important points is the difficulties of esophagus reconstruction. In an operation, since the stomach and intestines are used as a substitute, an invasion becomes large and an operation of elderly people becomes difficult. Although the improvement in a life prognosis is expected if cancer is removable, there are a lot of cases, who were too late for surgery of the esophageal cancer at the time of diagnosis. Then, a Swallow Stent with Hyperthermia function for the terminal esophageal cancer patients, for whom an operation cannot be conducted, was invented. The Swallow Stent with Hyperthermia function has three characteristics. 1. Completely noninvasive, 2. Hyperthermia on the carcinoma tissue. 3. Swallow function. Possibilities are expected as one of the alternative candidates for a terminal esophagus cancer therapy.

Preclinical development of SMA artificial anal sphincters

This article presents some progress in the development for preclinical trials of an artificial anal sphincter using shape memory alloys. The novel device has been proposed and developed by the author's group at Tohoku University. It has two dominant features different from other systems, which are either clinically available or still under development. One is that a solid driving element, a combination of shape memory alloy (SMA) ribbons and silicone elastomer sheets with a layered structure, is adopted for the opening and closing functions of the artificial sphincter. The other is a sandwich mechanism for the closing of bowel to reduce the risk of buckling induced ischemia which has been reported in hydraulically driven artificial sphincters with a radial squeezing mechanism. The device has fewer parts inside the body and therefore be implanted more easily. A new design eliminating the risk of heat burns enables long-term implantation and brings the device closer to practical use. Functionality and safety of the device have been proved in three-month animal experiments.

Development of the Pulsation Device for Rotary Blood Pumps

A rotary blood pump (RP) is desirable as a small ventricular assist device (VAD). However, an RP is nonpulsatile. We tried to develop a device that attaches a pulse to the RP. We also tried to develop a pulse-generating equipment that was not air-pressure driven. The ball screw motor was considered a candidate. The application of a small-sized shape memory alloy was also attempted. An electrohydraulic system was adopted, and actuator power was connected to the diaphragm. The diaphragm was placed on the outer side of the ventricle. Most RPs that have been developed all over the world drain blood from the ventricle. The wave of a pulse should be generated if a pulse is added by the drawn part. The output assistance from the outer side of the ventricle was attempted in animal experiments, and the device operated effectively. This device can be used during implantable operation of RP. This may serve as an effective device in patients experiencing problems in peripheral circulation and in the function of internal organs.

Addition of rhythm to non-pulsatile circulation

The development of a rotary blood pump (RP) is desirable as it can be used as a small ventricular assistance device (VAD). However, a RP does not generate any pulse. It may be physiologically better for the patient if the RP could generate a pulse. We have attempted to develop a device that produces a pulse in the RP. Intra-aortic balloon pumping (IABP) is effective in producing a pulse. However, the IABP cannot be implanted inside the body. Therefore, an attempt was made to develop pulse-generating equipment that was not driven by air pressure. The ball screw motor was considered as a possible candidate. In the future, we plan to apply small shape memory alloys. An electrohydraulic system was adopted, and actuator power output was connected to the diaphragm. The diaphragm was placed outside the ventricle. Most RPs developed throughout the world drain blood from the ventricle. The pulse wave should be generated if a pulse is added by the part from which blood is being drawn. In this study, animal experiments were conducted and the output assistance was tested from outside the ventricle. The device operated effectively in the animal experiment. The RP can easily be equipped with this device at the time of performing the implant operation. For a patient with problems of peripheral circulation and the internal organ function, it may prove to be an effective device.

Component Engineering for an Implantable System

Component engineering is important for the development of implantable-type rotary blood pumps (RP). The authors are conducting elementary development of an implantable artificial heart. A sensor system detects information in the living body. An automatic control system performs the drive control. Energy is provided by a transcutaneous energy transmission system (TETS). Various artificial hearts are being created. Miniaturization resulting from an increase in operating frequency is planned. A vibrating flow pump (VFP) has a reduced size of pumping chamber because of the high-speed reciprocating movement. Undulation pump ventricular assist devices (UPVAD) are small, lightweight rotary pumps. VFPs are useful in the medical treatment of multiple organ failure (MOF). UPVADs are planned to be permanent-use RPs. The purposes of these two artificial hearts differ, although they have a common component. The authors are developing TETS by using amorphous fibers, making efficient power transmission possible. Control information input from a micro or nano sensor is realized. A control algorithm has been developed and baroreflex control has been successful. Artificial heart development, fully exploiting component engineering, continues.

Development of an Implantable Undulation Type Ventricular Assist Device for Control of Organ Circulation

It is well known that a rotary blood pump (RP) is effective as a small ventricular assist device (VAD). It might be still more effective if pulsation was available. The undulation pump (UP), which is a type of small RP, can also produce pulsation. In Japan, a development project for an implantable type UP ventricular assist device (UPVAD) is now advanced. Six universities and some companies together have been in charge of the development project for 5 years. In this study, the influence which the UP under development has on circulation in internal organs was investigated. Goats with the same weight as an average Asian person were used for the experiment. The left chest cavity was opened after resection of the fourth rib and the heart was approached. A cannula was inserted in the left ventricle from the apex. An outflow cannula was inserted into the left descending aorta. Heart muscle was excised using a newly developed puncher. The UPVAD was implanted using a left-heart bypass system. The myocardial blood flow, carotid arterial blood flow, and the kidney blood flow were recorded together with an electrocardiogram, blood pressure, and the flow rate. In these animal experiments, the blood circulation dynamic state was stabilized and sufficient support of the left heart was observed. Myocardial blood flow, carotid arterial flow, and a kidney blood flow increase resulting from UPVAD support was observed. Often the problem of multiple organ failure is important at the time of clinical application of a ventricular assist device. Assisting circulation to internal organs is important for prevention of multiple organ failure. It was concluded that the UPVAD might be useful for prevention of multiple organ failure.

Functional Evaluation of an Artificial Anal Sphincter Using Shape Memory Alloys

This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.

Artificial myocardium with an artificial baroreflex system using nano technology

Where is the place which should be helped in a patient with congestive heart failure? The answer may be contraction of the heart. At Tohoku University, development research of "the artificial myocardium" has been conducted, using a ball screw type electromagnetic motor. Furthermore, super-miniaturization is being attempted at present. Thus, a system with shape memory alloy is being developed. The cooling speed problem was solved by the application of the Peltier element. A drive at a speed equal to that of a heartbeat was realized by the application of this system. At present, a ventricular assist device is used for patients waiting for a heart transplant in Japan. An air driven type system disturbs a patient's QOL remarkably because it is connected to the drive device. With our concept, energy is provided by using the electromagnetic force from outside of the body by the use of transcutaneous energy transmission system. Magnetic shielding by amorphous fibers was used at Tohoku University to improve the total efficiency. A natural heart can alter the cardiac output corresponding to the demand. Artificial internal organs must participate in the system of the living body, too. Tohoku University has developed a resistance based artificial heart control algorithm, which simulated a baroreflex system to cope with every demand. Nano level sensing equipment is now under development at Tohoku University. At present, development is being conducted aiming at an "intelligent artificial myocardium".

Development of an implantable high-energy and compact battery system for artificial heart

The purpose of this study was to demonstrate the feasibility of the use of an implantable, high-energy, and compact battery system for an undulation pump total artificial heart (UPTAH). The implantable battery system tested consists of six lithium-ion batteries in series, a charge unit, and a charge/discharge control unit. A lithium-ion battery is currently the best energy-storage device because it has more energy density, a better life cycle, and a smaller temperature rise than those of other secondary batteries. The performance of the implantable battery system was evaluated in an in vitro experiment using an electric load that simulated the UPTAH. Also, sufficiently reliable operation of a system for supplying energy to a UPTAH consisting of a transcutaneous energy transmission system (TETS) and an implantable battery system was confirmed in three experiments using goats. The results of the in vitro and in vivo experiments showed that the implantable battery system supplied sufficient current to the UPTAH for maintenance of physiological conditions in the goat with maximum rise in temperature to less than 43 degrees C.

Recent progress in artificial organ research at Tohoku University

Tohoku University has developed various artificial organs over the last 30 years. Pneumatic driven ventricular assist devices with a silicone ball valve have been designed by the flow visualization method, and clinical trials have been performed in Tohoku University Hospital. On the basis of these developments, a pneumatic driven total artificial heart has been developed and an animal experimental evaluation was conducted. The development of artificial organs in Tohoku University has now progressed to the totally implantable type using the transcutaneous energy transmission system with amorphous fibers for magnetic shielding. Examples of implantable systems include a vibrating flow pump for ventricular assist device, an artificial myocardium by the use of shape memory alloy with Peltier elements, and an artificial sphincter for patients with a stoma. An automatic control system for artificial organs had been developed for the ventricular assist devices including a rotary blood pump to avoid suction and to maintain left and right heart balance. Based upon the technology of automatic control algorithm, a new diagnostic tool for evaluating autonomic nerve function has been developed as a branch of artificial organ research and this new machine has been tested in Tohoku University Hospital. Tohoku University is following a variety of approaches aimed at innovation in artificial organs and medical engineering fields.

Solubilization study of local anesthetics into sodium dodecyl sulfate micelle using anesthetic cation selective electrodes

The free concentrations of local anesthetic cations in equilibrium with sodium dodecyl sulfate (SDS) micelle which solubilized the anesthetic were determined by using ion-selective electrodes sensitive to local anesthetics, procaine (PC), lidocaine (LC), and mepivacaine (MC). Solubilizate distribution between water and SDS micelle was analyzed by means of the stepwise mass-action model. Association constant, K(1), was found to depend upon the anesthetic concentration, which decreased exponentially as the concentration of free anesthetic increased. Therefore, K(1) should include the interaction function &phi;(A) as K(1)=K(int)exp{-&phi;(A)} where K(int) is an intrinsic association constant. &phi;(A) is an increasing function of the anesthetic concentration, which means that occupation of a solubilization site by a local anesthetic cation makes sequential solubilization more difficult. The binding affinity of an anesthetic with SDS micelle increased in the following order PC<LC<MC.The critical micelle concentration (CMC) of mixed micelle was determined as a function of the concentration of free anesthetic. The CMC decreased with an increasing amount of anesthetics solubilized. All the anesthetic compositions in the micelle calculated thermodynamically from the CMC data were larger than the corresponding ones in the aqueous phase. Although the local anesthetics used here do not form micelles by themselves, the CMC vs composition curve can be regarded as a part of a micellar phase diagram showing the negative azeotropic behavior, which reflects the attractive interaction between the anionic surfactant micelle and the local anesthetic cation.

Partitioning of uncharged local anesthetic benzocaine into model biomembranes

The partitioning of uncharged local anesthetic benzocaine (BzC) into molecular aggregates formed by cationic surfactant decylammonium chloride (DeAC) and phospholipid dipalmitoylphosphatidylcholine (DPPC) was studied from the surface tension and light transmittance measurements. The quantities concerning the partitioning of BzC, the compositions of BzC in the surface-adsorbed film and micelle and three kinds of differential partition coefficients corresponding to phase transitions of the DPPC bilayer membrane were evaluated from thermodynamic analysis of the experimental data. The surface-adsorbed film and micelle were more abundant in BzC than the aqueous solution and significantly large differential partition coefficients for the DPPC membranes were observed. The results clearly showed that the BzC molecules greatly partitioned into hydrophobic environments produced by surfactant-monolayer and phospholipid-bilayer membranes. The partitioning behavior of BzC was also compared with that of charged local anesthetic procaine hydrochloride (PC.HCl). It was shown that the PC.HCl molecule did not or hardly partition into such hydrophobic environments. The contrasting results of the partitioning between BzC and PC.HCl are attributable to the drastic decrease of hydrophilicity of BzC due to the lacking of ionic polar head group in comparison with PC.HCl.

Recent progress on the vibrating flow pump as a totally implantable ventricular assist device

This study describes the present state of progress in the development of the vibrating flow pump (VFP) ventricular assist system. We have proceeded with development aiming at a totally implantable ventricular assist system with smaller size and lighter weight appropriate for Asians like the Japanese by increasing the drive frequency. An actuator is important for the development of the miniature sized and lightweight artificial heart. We applied a linear motor for the mechanical part at first. The step motor was applied after that. This form may be best if we want the lightweight small sized motor for an actuator. The cross slider form is applied at present. It succeeded in the miniaturization compared with the linear motor. In the VFP-type ventricular assist system, the blood contact parts are a central vibration tube with inflow and outflow chambers. We designed round diaphragms to prevent thrombus formation. In addition, we developed an energy transmission system for total implantation. The VFP creates a high frequency oscillated blood flow. It has a unique flow pattern. Brain blood flow increased although the total flow of the circulation did not change in the frequency of 25 to 30 Hz. The quantitative evaluation of the autonomic nerve function during the left heart assistance with an oscillated blood flow was carried out by spectral analysis. Some influences on an autonomic nerve were observed by the VFP left heart assistance. We will continue development research with the aim of clinical application.

Partition coefficients of charged and uncharged local anesthetics into dipalmitoylphosphatidylcholine bilayer membrane: estimation from pH dependence on the depression of phase transition temperatures

Effects of the local anesthetics, dibucaine, bupivacaine and lidocaine on the phase transition temperatures of dipalmitoylphosphatidylcholine (DPPC) bilayer membrane were studied by the optical method. We focus our attention on pH dependence of the depression of main transition and pretransition temperatures. The temperatures of both transitions of DPPC bilayer membrane were depressed by the addition of anesthetics; the higher the value of pH, the larger the depression of main transition temperature and/or pretransition temperature by anesthetics. By extending the colligative thermodynamic framework to the depression of main transition temperature by an anesthetic, we can estimate the differential partition coefficient, which is defined by the difference in partition coefficients of an anesthetic into the ripple gel and liquid crystal phases. The difference in partition coefficient between the lamellar and ripple gel phases can also be estimated from the depression of pretransition temperature. Since the differential partition coefficients include both contributions of the charged and uncharged anesthetics, we could estimate the partition coefficients of the charged and uncharged anesthetic into the membranes from the pH dependence of differential partition coefficients. The liquid crystalline membrane of DPPC bilayer was more receptive to the uncharged local anesthetics than the charged species. The partition coefficients of the charged and uncharged anesthetics into the liquid crystalline phase of DPPC bilayer membrane were 3540 and 249000 (for dibucaine), 1120 and 83900 (for bupivacaine), 256 and 11700 (for lidocaine), respectively. The transfer free energy of uncharged anesthetics from the aqueous phase to the liquid crystalline membrane was well correlated to the local anesthetic potency.

[A case of nonresectable scirrhous type gastric cancer treated by hypertensive subselective chemotherapy with pharmacokinetic modulating chemotherapy]

There have been few effective chemotherapeutic regimens for scirrhous type gastric cancer. A 62-year-old male patient was admitted to our hospital because of anorexia and abdominal discomfort. Gastroendoscopy showed a type 4 advanced gastric cancer in the upper gastric body. Histologic study of biopsy specimens from the tumor revealed poorly differentiated adenocarcinoma. Examination by computed tomography and ultrasonography revealed swollen paraaortic lymph nodes and peritonitis carcinomatosa. The patient was diagnosed as having a nonresectable scirrhous type gastric cancer with peritonitis carcinomatosa and paraaortic lymph node metastasis. This patient was treated weekly with an intraarterial 5-FU (500 mg) and MTX (100 mg) including AT-II by a subcutaneously implanted port system placed into the thoracic aorta. Furthermore, he was administered tegafur/uracil (400 mg/day) 5 days weekly as a pharmacokinetic modulating chemotherapy (PMC). After eight courses of treatment of PMC, paraaortic lymph node swelling and ascites decreased. This chemotherapy produced a partial response in the peritonitis carcinomatosa and paraaortic lymph nodes. This chemotherapy was repeated preoperatively. We reconsidered this case to show indications for operation. The patient died suddenly of acute heart failure before the operation. This therapy was considered an effective treatment for nonresectable gastric cancer.

Effects of age and gender on the expression of brain-derived neurotrophic factor mRNA in rat retrosplenial cortex following administration of dizocilpine

Using in situ hybridization, we studied the effects of age and gender on the expression of brain-derived neurotrophic factor (BDNF) mRNA and heat shock protein hsp-70 mRNA in the rat retrosplenial cortex following administration of the noncompetitive NMDA receptor antagonist (+)-MK-801 (dizocilpine). Male and female Sprague-Dawley rats (5 weeks, 12 weeks, or 10 months old) were given a single intraperitoneal injection of saline (1 ml/kg) or dizocilpine (0.3, 1.0, or 3.0 mg/kg). No expression of BDNF mRNA and hsp-70 mRNA was detected in the rat retrosplenial cortex after administration of saline (1 ml/kg, IP). Administration of dizocilpine (0.3, 1.0, or 3.0 mg/kg, IP) caused a marked induction of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex of male and female rats, in a dose-dependent manner. Female rats were more sensitive to the induction of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex by dizocilpine as compared to male rats. It was also found that adult (12 weeks old) and aged (10 months old) rats were more sensitive to the induction of hsp-70 mRNA and BDNF mRNA in the retrosplenial cortex by dizocilpine as compared to young (5 weeks old) rats. These results suggest that the age and gender differences observed in the expression of BDNF mRNA and hsp-70 mRNA in the retrosplenial cortex by dizocilpine may be associated with the differences in dizocilpine-induced neurotoxicity observed with gender and age within the same region.

Psychiatric disorders in cancer patients: descriptive analysis of 1721 psychiatric referrals at two Japanese cancer center hospitals

BACKGROUND

Although a diagnosis of cancer today may no longer be considered to be the equivalent of a death sentence, many previous studies in Western countries have revealed that such a diagnosis places many kinds of emotional burden on a patient. However, few studies have focused on the nature of psychiatric disorders in Japanese cancer patients.

METHODS

We investigated the characteristics, reason for psychiatric consultation and psychiatric diagnosis of cancer patients by analyzing the database of patients referred to the Psychiatry Divisions at the National Cancer Center Hospital and the National Cancer Center Hospital East, Japan.

RESULTS

Among a total of 1721 referrals, most of the cancer patients (78%) were inpatients. Patients with lung cancer (19%) were the most common, followed by patients with breast cancer (13%) and with head and neck cancer (10%). More than half of the patients had recurrent and/or metastatic cancer and 60% of the patients had pain. The most common reason for the consultation was psychiatric evaluation (35%), followed by sleep disorders (19%), anxiety or fear (18%) and depression (18%). Regarding the psychiatric diagnosis, adjustment disorders were the most common (34%), followed by delirium (17%) and major depression (14%). The diagnosis of cancer had been disclosed to more than 99% of the patients.

CONCLUSION

The common psychiatric disorders observed in Japanese cancer patients were similar to those in the Western countries provided the cancer diagnosis is disclosed.

[A case of successful management of nonresectable pancreas cancer with liver metastasis by intra-arterial infusion chemotherapy with angiotensin-II and administration of tegafur/uracil]

Nontypical chemotherapy regimens exist for advanced pancreatic cancer. We herein report a 62-year-old man whose nonresectable pancreatic cancer was treated effectively with a new method of intra-arterial regional chemotherapy with angiotensin-II (AT-II). The patient was admitted to our hospital with obstructive jaundice and anorexia. He was diagnosed as having inoperable advanced pancreatic cancer with liver metastasis. Enteric-coated tegafur/uracil (400 mg) was administered for 3 weeks. Simultaneously, intraarterial infusion with 5-fluorouracil (500 mg) and infusion of methotrexate (100 mg) with 50 micrograms of AT-II was given every week. A catheter connected to a subcutaneously implanted port system was placed into the common hepatic artery. As a result of this treatment, the maximum diameter of the pancreatic tumor decreased from 3 cm to 2 cm on the CT-scan. Serum carbohydrate antigen 19-9 (CA19-9) decreased from 24,000 U/ml to 186 U/ml. Moreover, the performance status of patient also improved, and he was discharged from our hospital despite his terminal cancer. This regimen could well be effective in cases of advanced pancreatic cancer.

[Prostatic cancer developing after transurethral resection of the prostate for benign prostatic hyperplasia]

From January 1993 to June 1998, 319 cases were histopathologically diagnosed as prostatic cancer. In 7 of the 319 cases (2.2%) transurethral resection of the prostate (TUR-P) had been performed and a diagnosis of benign prostatic hyperplasia had been made with the resected specimens. The interval between TUR-P and the diagnosis of prostatic cancer ranged from 22 months to 15 years. All the cases showed an elevation of the prostate specific antigen (PSA) value (6.4-399 ng/ml, Tandem-R: RIA) at the time of cancer diagnosis. In 2 cases, PSA was measured in cancer screening. The clinical stage was stage B1 in 2 cases, stage B2 in 2 and D2 in 3. Only one case had been regularly followed-up after TUR-P, in which cancer was diagnosed by needle biopsy 22 months after TUR-P, because of the sustained high PSA values. Since most of such patients have an advanced stage of prostate cancer, it is of importance to have periodical follow-up examinations after TUR-P. The measurement of PSA appears the most reliable means in this way.

Brevican is degraded by matrix metalloproteinases and aggrecanase-1 (ADAMTS4) at different sites

Brevican is a member of the lectican family of chondroitin sulfate proteoglycans that is predominantly expressed in the central nervous system. The susceptibility of brevican to digestion by matrix metalloproteinases (MMP-1, -2, -3, -7, -8, -9, -10, and -13 and membrane type 1 and 3 MMPs) and aggrecanase-1 (ADAMTS4) was examined. MMP-1, -2, -3, -7, -8, -10, and -13 degraded brevican into a few fragments with similar molecular masses, whereas the degradation products of aggrecanase-1 had apparently different sizes. NH(2)-terminal sequence analyses of the digestion fragments revealed that cleavages of the brevican core protein by these metalloproteinases occurred commonly within the central non-homologous domain. MMP-1, -2, -3, -7, -8, -10, and -13 preferentially attacked the Ala(360)-Phe(361) bond, whereas aggrecanase-1 cleaved the Glu(395)-Ser(396) bond, which are similar to the cleavage sites observed with cartilage proteoglycan (aggrecan) for the MMPs and aggrecanase-1, respectively. These data demonstrate that MMP-1, -2, -3, -7, -8, -10, and -13 and aggrecanase-1 digest brevican in a similar pattern to aggrecan and suggest that they may be responsible for the physiological turnover and pathological degradation of brevican.

Effect of local anesthetics on the bilayer membrane of dipalmitoylphosphatidylcholine: interdigitation of lipid bilayer and vesicle-micelle transition

The phase transitions of dipalmitoylphosphatidylcholine (DPPC) bilayer membrane were observed by means of differential scanning calorimetry (DSC) as a function of the concentration of local anesthetics, dibucaine (DC x HCl), tetracaine (TC x HCl), lidocaine (LC x HCl) and procaine hydrochlorides (PC x HCl). LC x HCl and PC x HCl depressed monotonously the temperatures of the main- and pre-transition of DPPC bilayer membrane. The enthalpy changes of both transitions decreased slightly with an increase in anesthetic concentration up to 160 mmol kg(-1). In contrast, the addition of TC x HCl or DC x HCl, having the ability to form a micelle by itself, induced the complex phase behavior of DPPC bilayer membrane including the vesicle-to-micelle transition. The depression of both temperatures of the main- and pre-transition, which is accompanied with a decrease in enthalpy, was observed by the addition of TC x HCl up to 21 mmol kg(-1) or DC x HCl up to 11 mmol kg(-1). The pretransition disappeared when these concentrations of anesthetic were added, and the interdigitated gel phase appeared above these concentrations. The appearance of the interdigitated gel phase, instead of the ripple gel phase, brings about the stabilization of the gel phase by 1.8-2.4 kcal mol(-1). In the concentration range of 70-120 mmol kg(-1) TC x HCl (or 40-60 mmol kg(-1) DC x HCl), the enthalpy of the main transition exhibited a drastic decrease, resulting in the virtual disappearance of the main transition. This process includes the decrease in vesicle size with increasing anesthetic concentration, resulting in the mixed micelle of DPPC and anesthetics. Therefore, in this range of anesthetic concentration, the DPPC vesicle solubilized an anesthetic which coexists with the DPPC-anesthetic mixed micelle. Above the concentration of 120 mmol kg(-1) TC x HCl (or 60 mmol kg(-1) DC x HCl), there exists the DPPC-anesthetic mixed micelle. Two types of new transitions concerned with the mixed micelle of DPPC and micelle-forming anesthetics were observed by DSC.

[A case of metastatic extradural seminoma suspected intradural invasion by the measurements of HCG beta concentration in CSF]

A 34-year-old man underwent left orchidectomy for his left testicular seminoma. One month later, he developed paraplegia, hypesthesia under Th10 level and vesicorectal disturbance. He was diagnosed as having compressive myelopathy secondary to metastatic neoplasm at thoracic vertebra 10 and its extradural space which were revealed on magnetic resonance imaging. After administration of combination chemotherapy with cisplatin, etoposide and bleomycin, the extradural lesions diminished and the neurological symptoms gradually improved. In this case, intradural invasion of tumor cells was suspected because the level of human chorionic gonadotrophin beta subunit (HCG beta) concentration in cerebrospinal fluid (CSF) was higher than that in plasma, while radiographic scanning demonstrated regional tumor located at extradural space of Th10 level. It is important to evaluate the spread of tumor cells for the choice of therapy and the monitoring of HCG beta (plasma:CSF ratio) was considered to be one of the useful methods to detect the presence of central nerve system metastases from HCG-producing tumor.

[Centennial for the Meyer-Overton rule: anesthetics and receptors]

As a backlash to the dominance of lipid theories of anesthesia for almost a century, protein theories are prevalent at present. Lipid theories assume nonspecific interaction with membranes. Protein theories assume specific interaction with specific receptors in specific proteins. The Meyer-Overton rule does not specify the anesthetic action site to lipid membranes. The correlation between the olive oil solubility to the anesthetic potency means that the action sites have similar physical properties to olive oil. It does not discriminate between lipids and proteins. Olive oil is homogeneous (isotropic) liquid whereas membranes and proteins are structured (anisotropic). The physical properties of proteins and membranes are not uniform throughout the structure. The rule shows that the anesthetics bind multiple areas in nonspecific proteins and membranes. The diversity of anesthetic structures is difficult to reconcile with the idea that there is a specific receptor on specific proteins.

Artificial SMA valve for treatment of urinary incontinence: upgrading of valve and introduction of transcutaneous transformer

This paper is concerned with the development of an artificial urethral valve driven by shape memory alloy actuators, which is attached onto the urethra of a urinary incontinence sufferer for treating the involuntary micturition. Three types of compact cylindrical valves are assembled and their opening and closing functions are examined experimentally. The updated valve is heated and opened by using the transcutaneous energy transformer consisting of a pair of flexible spiral-formed copper wire coils. The experiment using the canine urinary canal verifies that the total system of the valve and the transformer works well as an artificial sphictor muscle and controls the urinary flow through the canal appropriately.

Increased expression of zif268 mRNA in rat retrosplenial cortex following administration of phencyclidine

Phencyclidine (PCP) has been shown to cause neurotoxicity in rat retrosplenial cortex following a single administration, although the precise mechanism underlying PCP-induced neurotoxicity is unclear. Using in situ hybridization and immunohistochemistry, we studied the effects of PCP on expression of immediate early gene zif268 mRNA and zif268 protein in the rat brain. High constitutive levels of zif268 mRNA and zif268 immunoreactivity were observed in the brain of control rats. Administration of PCP (12.5, 25 or 50 mg/kg, i.p., 6 h) caused marked induction of zif268 mRNA in the rat retrosplenial cortex, in a dose-dependent manner. However, the basal levels of zif268 mRNA in the other regions of cerebral cortex were decreased by administration of PCP. Emulsion-autoradiographical study suggested that marked expression of zif268 mRNA was observed in the layers III and IV of retrosplenial cortex where the neurotoxicity of PCP was detected. Furthermore, zif268 immunoreactivity in the layer IV of retrosplenial cortex was not changed by administration of PCP (25 mg/kg, i.p., 5 h), but that in the other layers of retrosplenial cortex was reduced by PCP. These results suggest that immediate early gene zif268 may, in part, play a role in the neurotoxicity of NMDA receptor antagonists such as PCP.

Non-Hodgkin lymphoma and coexisting primary cancers: a retrospective clinical analysis of 10 patients

The simultaneous occurrence of non-Hodgkin lymphoma (NHL) and primary cancers is rare, and the treatment strategy for both malignancies is unclear. The authors analyzed the clinical records of 10 patients with NHL and coexisting primary cancers. All patients initially had symptoms of NHL, and all carcinomas were found at the initial workup of NHL by chance. The most common primary sites of coexisting cancers were the stomach (six patients) and the colon (two). Histologically, the majority of NHLs were intermediate grade, and all lesions were B-cell type. All primary cancers were adenocarcinoma. Initially, NHL was treated with radiotherapy or chemotherapy. Six primary cancers were resected surgically or endoscopically after the remission of NHL. The remaining four patients received no treatment for primary cancers because of advanced stages or early relapse of NHL. Three patients died of NHL, one died of cancer, and six were still alive, five without evidence of disease and one with disease. The authors conclude that early detection of a coexisting cancer and appropriate treatment after the remission of NHL may increase the possibility of a cure.

Specific and non-specific binding of long-chain fatty acids to firefly luciferase: cutoff at octanoate

Firefly luciferase emits a burst of light when the substrates luciferin and ATP are mixed in the presence of oxygen. We (I. Ueda, A. Suzuki, Biophys. J. 75 (1998) 1052-1057) reported that long-chain fatty acids are specific inhibitors of firefly luciferase in competition with luciferin in microM ranges. They increased the thermal transition temperature. In contrast, 1-alkanols of the same carbon chain length inhibited the enzyme non-competitively in mM ranges and decreased the transition temperature. The present study showed that the action of fatty acids switched from specific to non-specific when the carbon chain length was reduced below C8 (octanoate). The fatty acids longer than C10 inhibited the enzyme in microM ranges whereas those shorter than C8 required mM ranges to inhibit it. The longer fatty acids increased whereas shorter fatty acids decreased the transition temperature. The Hill coefficients of longer chain bindings were less than one whereas those of shorter chain were more than one. The shorter fatty acids interacted with the enzyme cooperatively at multiple sites. Binding of the longer fatty acids is limited. Fatty acids longer than C10 are high-affinity specific binders and followed Koshland's induced-fit model. Those shorter than C8 are low-affinity non-specific denaturants and followed Eyring's rate process model. These results contradict the general consensus that the size of the receptor cavity discriminates specific binders.

Does pressure antagonize anesthesia? Opposite effects on specific and nonspecific inhibitors of firefly luciferase

Ueda and Suzuki (1998. Biochim. Biophys. Acta. 1380:313-319; 1998. Biophys. J. 75:1052-1057) reported that myristic acid inhibited firefly luciferase in microM range in competition with luciferin, whereas anesthetics inhibited it in millimeter ranges noncompetitively with luciferin. Myristate increased, whereas anesthetics decreased, the thermal denaturation temperature. The present study showed that high pressure increased the steady-state light intensity of the halothane-doped firefly luciferase but decreased that of the myristate-doped firefly luciferase. The steady-state light intensity showed a maximum at 19.1 degrees C. At 19.1 degrees C, high pressure did not affect the light intensity in the absence of the inhibitors. In the presence of 0.5 mM halothane, however, 25 MPa pressure (maximum effect) increased the light intensity to 106.0% of the control without the inhibitor. In the presence of 2.5 microM myristate, 40 MPa pressure decreased the light intensity to 90.9% of the control. When the temperature was 25 degrees C in the absence of inhibitors, 40 MPa pressure increased the light intensity 119.2% of the ambient value. At 0.5 mM halothane, 40 MPa pressure further increased the light intensity to 106.1% above the control 40 MPa value. At 2.5 microM myristate, 40 MPa pressure decreased the light intensity to 90.1% of the control 40 MPa value. From the pressure dependence of the light intensity, the volume change DeltaV of the enzyme was estimated at 25 degrees C: 0.5 mM halothane increased DeltaV = +3.93 cm3 mol-1, whereas 2.5 microM myristate decreased DeltaV = -7.66 cm3 mol-1. Present results show that there are distinct differences between the specific and nonspecific ligands in their response to high pressure. Myristate, which competes with luciferin, decreased the protein volume and stabilized the conformation against thermal perturbation. Halothane, which does not compete with the substrate, increased the protein volume and destabilized the conformation.

Does pressure antagonize anesthesia? High-pressure stopped-flow study of firefly luciferase and anatomy of initial flash

The antagonizing effect of high pressure against anesthesia is well known. With purified firefly luciferase, however,. Biophys. J. 60:1309-1314) reported that high pressure did not affect the initial flash intensity. Firefly luciferase emits a burst of light when the substrates luciferin and ATP are added in the presence of O2. The light intensity decays rapidly and the weak light lasts for hours. The initial flash is a transient event and is not in a steady state. The steady state is represented by the slope of the linear part of the integral of the light output. The present study used a high-pressure stopped-flow system to compare the pressure effects on the initial flash intensity and the steady-state light intensity. The flash intensity did not change by the application of hydrostatic pressure in the presence or absence of chloroform or 1-octanol. In contrast, high pressure increased the steady-state light intensity. The application of 12 MPa pressure increased the steady-state light intensity of firefly luciferase inhibited by 5 mM chloroform or 0.7 mM 1-octanol by 19.7% and 18.8%, respectively. When analyzed by the rapid reaction kinetics of the transition state theory, the initial peak intensity represents the total amount of active enzyme and is unrelated to the reaction rate. Anesthetics inhibited the initial flash by unfolding the protein, thereby decreasing the concentration of the active enzyme. Pressure affected the steady-state light intensity by changing the reaction rates.

Membrane-buffer partition coefficients of a local anesthetic tetracaine monitored by an anesthetic sensor; effects of temperature and pH

Binding of a local anesthetic tetracaine (TC) to dimyristoylphosphatidylcholine (DMPC) bilayer membrane was studied by the potentiomerty with an ion-selective electrode sensitive to TC cation. DMPC membrane-buffer partition coefficient (K(app)) was determined in mole fraction unit as a function of pH for the lamellar gel (at 12 degrees C), ripple gel (at 20 degrees C), and liquid crystal (at 30 degrees C) phases. The partition coefficients of charged (K+) and uncharged TC (K0) into the DMPC membranes were estimated from the pH-dependence of K(app). The three states of DMPC membranes were more receptive to the uncharged TC than the charged species.

Barotropic phase transitions and pressure-induced interdigitation on bilayer membranes of phospholipids with varying acyl chain lengths

The bilayer phase diagrams of a series of 1, 2-diacylphosphatidylcholines containing linear saturated acyl chain (C=13, 14, 15, 16, 17 and 18) were constructed by two kinds of high-pressure optical methods. One is the observation of isothermal barotropic phase transition and the other is the isobaric thermotropic phase transition. The temperature of the main transition from the ripple gel (Pbeta') phase to the liquid crystal (Lalpha) phase for each lipid was elevated by pressure. The slope of the temperature-pressure diagram, dT/dP, was in the range of 0.21-0. 23 K MPa-1 depending on the acyl chain length. The temperature of the pretransition from the lamellar gel (Lbeta') phase to the Pbeta' phase for each lipid was also elevated by pressure. The slope of phase boundary, dT/dP, for the pretransition was in the range of 0. 12-0.14 K MPa-1. Both temperatures of the main and pretransition under ambient pressure increased with an increase in acyl chain length. The chain length dependences of the pretransition and main transition temperatures describe smooth curves with no evidence of odd/even discontinuities. Pressure-induced interdigitated gel (LbetaI) phase was observed beyond 300 MPa for 14:0-PC, 175 MPa for 15:0-PC, 100 MPa for 16:0-PC, 80 MPa for 17:0-PC and 70 MPa for 18:0-PC, respectively. The minimum pressure for the interdigitation of lipid bilayer membranes decreased with an increase in acyl chain length in a manner of non-linear relation. The slopes of phase boundary between Lbeta' and LbetaI phases transformed from the negative slope to the positive slope as the pressure increases.

Barotropic phase transitions of dioleoylphosphatidylcholine and stearoyl-oleoylphosphatidylcholine bilayer membranes

In order to understand the effect of cis unsaturation on the thermotropic and barotropic phase behavior of phospholipid bilayer membranes, the phase transitions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) bilayer membranes were observed by high-pressure optical method. With respect to DOPC bilayer membrane, the so-called main transition between the liquid crystalline (Lalpha) and the lamellar gel (Lbeta) phases was observed in water at above 0 degrees C under high pressure, in addition to the transition between the Lalpha and the lamellar crystalline (L(C)) phases in 50% aqueous ethylene glycol. The pressure of main transition increased linearly with an increase in temperature. Extrapolation of temperature (T)-pressure (P) phase boundary to ambient pressure suggests the temperature of the main transition to be -40.3 degrees C, which has never been found by the DSC method. On the other hand, the temperature of L(C)/Lalpha phase transition in 50% aqueous ethylene glycol was found to be -12.0 degrees C at ambient pressure. The main transition temperatures for DSPC, SOPC and DOPC are 55.6, 6.7 and -40.3 degrees C, respectively, at ambient pressure. The substitution of cis unsaturated chain for saturated chains of DSPC brings about the depression of the main transition temperature by about 48 (+/-1) degrees C for each chain. The volume changes (deltaV) associated with the transitions were calculated from the transition enthalpy (deltaH) and the slope of T-P diagram (dT/dP) by means of the Clapeyron-Clausius equation. The value of deltaV for the main transition of SOPC bilayer membranes was reduced to half the volume change for DSPC bilayers, which means the introduction of the cis double bond in the acyl chain of lipids brings about the reduction of deltaV because of the disordered packing of unsaturated chains in the gel phase of lipid bilayer membranes.

Development and evaluation of totally implantable ventricular assist system using a vibrating flow pump and transcutaneous energy transmission system with amorphous fibers

We have developed a vibrating flow pump (VFP) that can generate oscillated blood flow with a relatively high frequency (10-50 Hz) for a totally implantable ventricular assist system (VAS). To evaluate the newly developed VAS, left heart bypasses, using the VFP, were performed in chronic animal experiments. Hemodynamic parameters were recorded in a data recorder in healthy adult goats during an awake condition and analyzed in a personal computer system through an alternating-direct current converter. Basic performance of the total system with a transcutaneous energy transmission system were satisfactory. During left ventricular assistance with the VFP, Mayer wave fluctuations of hemodynamics were decreased in the power spectrum, the fractal dimensions of the hemodynamics were significantly decreased, and peripheral vascular resistance was significantly decreased. These results suggest that cardiovascular regulatory nonlinear dynamics, which mediate the hemodynamics, may be affected by left ventricular bypass with oscillated flow. The decreased power of the Mayer wave in the spectrum caused the limit cycle attractor of the hemodynamics and decreased peripheral resistance. These results suggest that this newly developed VAS is useful for the totally implantable system with unique characteristics that can control hemodynamic properties.

Extremely Strong Interaction of Sodium Decyl Sulfate and Decyltrimethylammonium Bromide in Molecular Aggregates

The thermodynamic behavior of a mixture of sodium decyl sulfate (SDeS) and decyltrimethylammonium bromide (DeTAB) in aqueous solution and in molecular aggregates such as surface adsorbed films and micelles was investigated by measuring the electric conductivity and surface tension of the aqueous solutions. The thermodynamic quantities in solution and those in the molecular aggregates were evaluated from the experimental conductivity and surface tension data. The results for molar conductivity showed that dimerization or ion-pair formation of the SDeS and DeTAB molecules does not occur in aqueous solution and the mixture behaves as uni-univalent strong electrolyte below the critical micelle concentration (CMC). Contrary to the results in the aqueous solution, we found significant nonideal behavior in the phase diagrams of surface adsorption; that is, equimolar mixture of SDeS and DeTAB exists in the adsorbed film at almost all compositions irrespective of the bulk composition in the solution. The same result was also observed in the phase diagram of micelle formation. There was no difference in phase diagrams between surface adsorption and micelle formation at the CMC. The great nonideal mixing of SDeS and DeTAB in the molecular aggregates is undoubtedly attributable to the extreme attractive interaction between oppositely charged polar head groups of surfactants as well as to cohesion between hydrophobic groups. Further, in a low concentration region, it turned out that equimolar composition is preserved in the film during phase transition of the mixed adsorbed film of SDeS and DeTAB from a gaseous state to an expanded state.

Glutathione derivatives enhance adriamycin cytotoxicity in a human lung adenocarcinoma cell line

We evaluated the effects of a panel of glutathione derivative (S-butyl, S-decyl, S-ethyl, S-heptyl, S-hexyl; S-methyl, S-nonyl, S-octyl, S-propyl and S-pentyl glutathiones) on glutathione-S-transferase activity in the cell lysates of a human lung cancer, PC-9. Glutathione derivatives inhibited glutathione-S-transferase activity in PC-9 cell lysates by up to 67%. When PC-9 cells were incubated with the IC50 concentration of adriamycin (200 nM) and with nontoxic concentrations (1 microM) of the glutathione derivatives, cytotoxicity ranged from -20% to +55% of the control levels. Enhancement of adriamycin toxicity by glutathione derivatives was significantly correlated with the inhibition of glutathione-S-transferase activity. S-decyl-glutathione, which was one of the most potent inhibitors of glutathione-S-transferase activity, significantly enhanced the adriamycin-induced antitumor effect in vivo. Findings suggest that some glutathione derivatives, including the S-decyl, S-octyl, and S-hexyl glutathiones, enhance adriamycin-induced cytotoxicity in part by inhibiting glutathione-S-transferase and that these agents may be useful as chemosensitizers for adriamycin therapy. In conclusion, the present results showed that some glutathione derivatives enhanced sensitivity of tumor cells to ADR by inhibiting GST activity. The use of BSO and EA as sensitizers to chemotherapy is currently being evaluated in clinical trials. The present data suggest that the use of GSH derivatives to modulate GST activity may improve the response to ADR.

Effects of pressure and local anesthetic tetracaine on dipalmitoylphosphatidylcholine bilayers

The temperature-pressure phase diagram of dipalmitoylphosphatidylcholine (DPPC) multilamellar vesicles was constructed in the presence of a local anesthetic tetracaine hydrochloride (TC-HCl). The phase-transition temperatures under various pressures were determined by the method of high-pressure light transmission. The temperature of the main transition from the ripple gel (P'(beta)) to the liquid crystal (L(alpha)) phase was depressed by the addition of TC-HCl and elevated by application of pressure up to 150 MPa. The temperature of the pretransition from the lamellar gel (L'(beta)) to the P'(beta) phase was also depressed by the addition of TC-HCl below ca. 10.0 mmol kg(-1) and elevated by the pressure below ca. 50 MPa. Therefore, pressure-anesthetic antagonism for both phase-transitions was confirmed. The pressure-induced interdigitated gel (L(beta)I) phase has been observed under high pressure above 100 MPa in the absence of TC-HCl. The L(beta)I phase is known to be induced also by a variety of small amphiphilic molecules such as ethanol, benzyl alcohol and TC-HCl. In the presence of TC-HCl ranging in concentration up to 20.0 mmol kg(-1), the L(beta)I phase instead of the P'(beta) phase appeared at higher pressure. Present results revealed that pressure facilitates, rather than antagonizes, the effect of TC-HCl on the occurrence of interdigitated gel phase. Furthermore, two regions of two phase coexistence were observed under high pressure in the presence of TC-HCl. One is probably a region of coexisting L(beta)I and L(alpha) phase, which was found between L(beta)I and L(alpha) phases under various pressures. The other is probably a region of coexisting L'(beta) and L(beta)I phase, which was observed in the presence of TC-HCl up to 10.0 mmol kg(-1) at the pressure above 40 MPa and at the temperature below ca. 35 degrees C.

[A comparative study of the effects of granisetron alone and a combination of granisetron plus steroids on CDDP-based combination chemotherapy-induced emesis--outcomes of a multicenter randomized comparative study using the central registration method. Nara Medical University Kytril Study Group]

The present investigation was conducted to examine the effects of granisetron alone and a combination of granisetron plus steroids on CDDP-based combination chemotherapy-induced emesis by multi-institutional randomized comparative trial using a central registration method. A total of 62 patients with urological cancer enrolled this study were randomized into two groups: granisetron (40 micrograms/kg) only group and granisetron (40 micrograms/kg) plus steroids (500 mg of methylprednisolone or 8 mg of dexamethasone) group. There were 31 patients eligible in the granisetron only group and 28 in the combination group. The same anti-emetic treatments were given in the recycling courses of chemotherapeutic regimens. Therefore, eligible patients of the second and the third cycle numbered 31 (17 in the granisetron only group, 14 in the combination group) and 21 (11 in the granisetron only group and 10 in the combination group). Significant inhibition of acute emesis in combination group was observed when compared with the granisetron only group in each cycle. Delayed emesis was also significantly inhibited in the combination group on Day 2 and 3 of the first cycle and on Day 2 of the second and third cycle. In addition, appetite loss was significantly reduced in the combination group on Day 2 and 3 of the first and second cycle. No adverse events were seen in either group. These results suggested that a combination of granisetron and steroids was useful for preventing CDDP-based combination chemotherapy-induced emesis.