In vivo stimulation on rabbit retina using CMOS LSI-based multi-chip flexible stimulator for retinal prosthesis.

We have performed in vivo electric stimulation experiments on rabbit retina to demonstrate feasibility of CMOS LSI-based multi-chip flexible neural stimulator for retinal prosthesis. We have developed new packaging structure with an improved flexibility and device control system which totally controls the LSI-based multi-chip stimulator, counter electrode, and stimulation generator. We have implanted the fabricated multi-chip stimulator into sclera pocket for STS (Suprachoroidal Transretinal Stimulation) configuration. We successfully obtained EEP (Electrically Evoked Potential) on visual cortex evoked by the multi-chip stimulator.

Laboratory investigation of microelectronics-based stimulators for large-scale suprachoroidal transretinal stimulation (STS).

This paper describes the technological developments underlying the realization of a reliable and reproducible microchip-based stimulator with a large number of stimulus electrodes. A microchip-based stimulator with over 500 electrodes for suprachoroidal transretinal stimulation (STS) is proposed in this paper, and an example is presented. To enhance reliability and reproducibility for such a large array, we introduce a flip-chip bonding technique and place microchips on the reverse side of a substrate. A square microchip of size 600 microm was fabricated using 0.35 microm standard CMOS process technology. Twelve microchips were flip-chip bonded on a polyimide substrate through Au bumps. To evaluate the feasibility of the proposed device, we successfully fabricated a stimulator with 12 microchips and 118 electrodes made of Pt/Au bumps, and demonstrated their operation in a saline solution for 2 weeks. Also, to evaluate the device operation in vivo, a stimulator with one active IrO(x) electrode was implanted into the scleral pocket of a rabbit and electrical evoked potential (EEP) signals with a threshold of 100 microA were obtained. We also fabricated a simulator with 64 microchips that has 576 electrodes (9 electrodes in a microchip times 64 microchips).

Analysis of swertiamarin in Swertia herb and preparations containing this crude drug by capillary electrophoresis.

Swertia herb (florescent whole plantof Swertia japonica, Gentianaceae) has long been utilized as a folk medicine in Japan. It is often blended in general gastroenteric drugs as a bitter stomachic. Swertiamarin, a bitter secoiridoid glycoside, is the representative constituent of this crude drug and Swertia herb is normally evaluated by the swertiamarin content. To date, papers have described the discrimination of Swertia herbs from other bitter crude drugs, estimation of swertiamarin and seasonal variation in swertiamarin content using thin-layer chromatography, while other papers have reported quantitative determination of swertiamarin using high-performance liquid chromatography (HPLC). In our previous papers, we reported analyses of the constituents of some crude drugs using capillary electrophoresis (CE). To aid in the evaluation of crude drugs, we succeeded in our attempt to separate and determine the quantity of swertiamarin in Swertia herb. Subsequently, we applied the same analytical condition to estimate the swertiamarin contents in Japanese pharmacopoeia stomachic preparations, in OTC gastroenteric drugs and in OTC hair tonics containing Swertia herb.

A Case of Reversed Ophthalmic Artery Flow without Occlusion of the Internal Carotid Artery.

Background: We report a case of reversed ophthalmic artery (OA) flow showing neither occlusion of the internal carotid artery (ICA) nor ophthalmic symptoms.Case: An 82-year-old man had transient blindness in both eyes. After left carotid endarterectomy, ophthalmic symptoms improved in the right and left eyes. Afterwards, he had a relapse in the left eye.Results: There was no unusual impression in the ophthalmic examinations, but color Doppler imaging showed reduced flow in the left OA, reversal of flow direction in the right OA. The central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were not detected in the left eye but were detected in the right eye. Digital subtraction angiography demonstrated that the right OA was not contrasted with the right ICA, despite there being no stenosis or occlusion of the right ICA.Conclusions: We suggest that carotid surgery may affect the ocular circulation of the opposite side, and reversed OA flow as a collateral pathway from the external carotid artery may occur in the absence of carotid artery stenosis. Good circulation of the CRA and SPCA may preclude manifestation of ophthalmic symptoms even if the OA flow is reversed.

[A case of reversed ophthalmic artery flow without occlusion of the internal carotid artery].

BACKGROUND: We report a case of reversed ophthalmic artery (OA) flow showing neither occlusion of the internal carotid artery (ICA) nor ophthalmic symptoms. CASE: An 82-year-old man had transient blindness in both eyes. After left carotid endarterectomy, ophthalmic symptoms improved in the right and left eyes. Afterwards, he had a relapse in the left eye. RESULTS: There was no unusual impression in the ophthalmic examinations, but color Doppler imaging showed reduced flow in the left OA, reversal of flow direction in the right OA. The central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were not detected in the left eye but were detected in the right eye. Digital subtraction angiography demonstrated that the right OA was not contrasted with the right ICA, despite there being no stenosis or occlusion of the right ICA. CONCLUSIONS: We suggest that carotid surgery may affect the ocular circulation of the opposite side, and reversed OA flow as a collateral pathway from the external carotid artery may occur in the absence of carotid artery stenosis. Good circulation of the CRA and SPCA may preclude manifestation of ophthalmic symptoms even if the OA flow is reversed.

Is nitrotyrosine generated in human erythrocytes in circulation?

Nitrotyrosine is considered a stable biomarker of reactive nitrogen species, including nitrogen dioxide (NO2) and peroxynitrous acid (ONOOH) in biomaterials. There are inconsistent observations on the detection of free and protein-associated nitrotyrosine in normal human plasma. Human erythrocytes, differentiated from erythrocyte precursor cells in the bone marrow, circulating in the body for an average of 120 d, and finally removed by spleen macrophages, may be exposed to reactive nitrogen species. In the present study, membrane proteins and hemoglobin from the senescent erythrocyte population were compared with those from young erythrocytes separated from the same individuals in their nitrotyrosine presence using newly prepared rabbit polyclonal anti-nitrotyrosine-ribonuclease A and anti-nitro(N-butoxycarbonyl)tyrosine-bovine serum albumin antibodies. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the membranes and hemoglobin, and subsequent Western blot analysis, showed that these antibodies only slightly bind to the bands of the proteins from both young and senescent erythrocytes, whereas these antibodies definitely bind to the protein bands of membranes and hemoglobin nitrated by NO2 or ONOOH in vitro. This result indicates that nitrotyrosine is not detected in the membrane proteins and hemoglobin in human normal erythrocytes in circulation. However, this does not conclude that erythrocytes are not exposed to reactive nitrogen species in the circulation.

Effect of beta-carotene on the transformation of tyrosine by nitrogen dioxide and peroxynitrous acid.

In the NO2-exposure of tyrosine in 70% dioxane/phosphate buffer (pH 7.4), beta-carotene enhanced the degradation of tyrosine and/or 3-nitrotyrosine produced, whereas alpha-tocopherol and ascorbyl palmitate inhibited the transformation of tyrosine into 3-nitrotyrosine. Generation of certain active species in the interaction of beta-carotene with NO2 was suggested. Ascorbyl palmitate effectively and alpha-tocopherol slightly inhibited the transformation of tyrosine in the NO2-exposure in the presence of beta-carotene. In the reaction of tyrosine with ONOO-/ONOOH, beta-carotene enhanced the degradation of 3-nitrotyrosine produced suggesting generation of certain active species, whereas alpha-tocopherol and ascorbyl palmitate completely suppressed the transformation of tyrosine into 3-nitrotyrosine.

The prevalence of Balantidium coli infection in fifty-six mammalian species.

A total of 375 fecal samples of 56 mammalian species belonging to 17 families of 4 orders were examined for the detection of Balantidium coli from December 1994 to August 1995. As a result, B. coli was found from 6 species belonging to 4 families of 2 orders (Primates and Artiodactyla) of host animals examined. White-handed gibbon (Hylobates lar), squirrel monkey (Saimiri sciurea) and Japanese macaque (Macaca fuscata) were new hosts for B. coli. All the wild boar (Sus scrofa) and chimpanzee (Pan troglodytes) examined were positive. The highest number of B. coli was obtained from a chimpanzee (1,230/g feces). No B. coli was detected from the animals of orders Rodentia and Carnivora including dogs and cats. The rarity of B. coli infection in breeding animals in Japan. suggests that there is no serious problem in controlling infections.

A novel method to prepare monodisperse microparticles.

The membrane emulsification method was adopted to prepare monodisperse albumin microspheres. Uniform-sized emulsion droplets were successfully obtained by passing albumin solution through the membrane into kerosene at appropriate applied pressures. After heating the emulsion, monodisperse albumin microspheres were prepared and the heat-denaturing process itself did not affect their monodispersity once uniform emulsion droplets had been prepared. The shape and size of the albumin microspheres were strongly dependent on the concentration of the albumin solution and the heat denaturing temperature. Lower albumin concentrations produced non-spherical particles and higher denaturing temperatures made the particles smaller. Incorporated riboflavin released quite rapidly from the albumin microspheres, and increases in both albumin concentration and denaturing temperature caused the drug release to be sustained, presumably because a rigid and dense matrix was formed within the albumin microspheres.

[Malignant tumors in a Japanese geriatric hospital].

We studied the cases of 909 patients with malignant tumors (497 men and 412 women) who were admitted to Tokyo Metropolitan Geriatric Hospital from April 1994 to July 1995. The mean age was 78.6 years (range: 60 to 103 years). The most common tumors were gastric cancer, colo-rectal cancer, and lung cancer. However, the most common tumors in those who died (n = 263) were gastric cancer, lung cancer, and liver cancer. In 425, abnormalities were found during routine health checks or incidental laboratory examinations, while the patients were asymptomatic. On the first admission, 23.4% were found distant metastases. The rate of complications with other diseases was 82.3%. About one third (31.2%) were informed of their situation, and 18.5% had not received any treatment for their malignancies. In 63%, performance status at the time of discharge was the same as that measured on admission or better.

Effects of lecithinized superoxide dismutase on rat spinal cord injury.

Although superoxide dismutase (SOD) has been reported to promote functional recovery in ischemic spinal cord injury, it presents many difficulties in practical use primarily due to its short half-life in vivo and low tissue affinity. In this study, we investigated the effects of a new type of SOD, a lecithinized superoxide dismutase (PC-SOD), on motor disturbances, spinal cord edema, levels of myeloperoxidase (MPO), and spinal cord blood flow (SCBF) after spinal cord injury (SCI) in rats. PC-SOD is reported to show a delayed plasma disappearance in vivo in rats and has a higher affinity for vascular endothelium cells, neutrophils, and other cells than unmodified SOD. PC-SOD (4000 units/kg), unmodified SOD (4000 units/kg), or vehicle was injected intravenously 30 min after SCI. Four hours after SCI, SOD activities in spinal cord tissue and plasma were significantly higher in the PC-SOD group than in the unmodified SOD group. In the PC-SOD-treated rats, motor function was significantly better than in the other 2 groups of rats. PC-SOD significantly suppressed MPO activity, an indicator of neutrophils infiltration, in the spinal cord, at 4, 8, and 24 h after SCI, and spinal cord edema at 24 h after SCI. Moreover, the decrease of SCBF after SCI was less marked in the PC-SOD group. The present results suggest that lecithinization can improve the drug delivery of SOD to the spinal cord and PC-SOD may be an alternative pharmacological treatment for SCI.

Induction and its spread of apoptosis in rat spinal cord after mechanical trauma.

This study was undertaken to examine the spinal cord of rats after trauma for the induction of apoptosis. DNA ladder formation was demonstrated by gel electrophoresis of the DNA obtained from the spinal cord at the site of injury after trauma from 12 h to 8 days and was most significant on Days 3 and 4. As for the longitudinal spread of the injury in the spinal cord, the ladder formation was observed in the two segments adjacent to the site of trauma 3 days after trauma. Histological examination using in situ end labeling also demonstrated the appearance of apoptosis. These results provide the evidence for the induction of apoptosis in the spinal cord after trauma in rats.

Involvement of an intercellular adhesion molecule 1-dependent pathway in the pathogenesis of secondary changes after spinal cord injury in rats.

The intercellular adhesion molecule 1 (ICAM-1) plays an important role in immune responses by promoting infiltration of neutrophils into tissues; however, its implication in the secondary destructive pathomechanism after the initial mechanical injury to the spinal cord has not been clarified yet. This study was conducted to examine the role of ICAM-1 in this process after spinal cord injury (SCI) in rats. The expression of ICAM-1 mRNA was investigated by the reverse transcription-PCR method and the effect of monoclonal antibody (mAb) to ICAM-1 on SCI was evaluated by measuring various parameters. ICAM-1 mRNA expression correlated with the severity of injury and reached its maximum level 6 h after SCI. Intravenous injection of ICAM-1 mAb (1 mg/kg) 30 min after SCI reduced motor disturbance and enhanced recovery. Moreover, it significantly suppressed myeloperoxidase activity by 43.0% and spinal cord edema by 1.1% in the injured spinal cord tissue. The posttraumatic drop in spinal cord blood flow was also improved. These results suggest that ICAM-1 is deeply involved in the secondary self-destructive process after mechanical injury of the spinal cord and should be an effective target for developing a pharmacological treatment for SCI.

Influence of minor trauma to the neck on the neurological outcome in patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

The influence of minor trauma to the neck on the neurological outcome in patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine was evaluated retrospectively. Out of 118 patients treated in our clinic for cervical OPLL between 1976 and 1992, 27 had sustained minor trauma to the cervical spine. Of these 27 patients, 13 developed myelopathy, seven showed deterioration of preexisting myelopathy, and no neurological change was observed in seven patients. Regarding the relationship between the diameter of the residual spinal canal and the neurological outcome in these 27 patients, 18 out of the 19 patients with a narrow residual spinal canal (< 10 mm) developed neurological deterioration, whereas that occurred in only two of the eight patients with a wider spinal canal (> or = 10 mm). Although the severity of myelopathy and the transverse area of the spinal cord measured from T1-weighted magnetic resonance images, in patients who had sustained minor trauma was not statistically different from patients without trauma, neurological recovery after surgical treatment was poorer in the former group than in the latter. These results indicate that even indirect minor trauma to the neck can cause irreversible changes in the spinal cord if there is marked stenosis of the cervical spinal canal; such patients who are at risk, must be educated, and should be told to avoid even minor injuries at any cost.

[An analysis of 41 elderly patients with urosepsis].

We performed a clinical evaluation in 41 patients with urosepsis at Tokyo Metropolitan Geriatric Hospital from July 1992 through March 1993. The most common organism isolated from the patients was Escherichia coli (46.3%), followed by Pseudomonas aeruginosa (9.8%), Methicillin-resistant staphylococcus aureus (7.3%), and mycetes (7.3%). The most frequent underlying disease was cerebrovascular disease (34.1%) and malignancies were observed 29.2% of all cases. Twenty-six patients (63.4%) had indwelling urethral catheters. Indwelling catheters were suspected to be related to the onset of urosepsis in 16 cases. Total mortality of urosepsis was 4.9% (2/41) in this study. We speculate that the main cause of urosepsis is a long-term use of urethral catheterization, especially in elderly patients with severe complications who are vulnerable to infections. It is important to assess and correct the conditions of dysuria of individual patients before placing indwelling urethral catheters.

[Monitoring tumor response to therapy by means of 31P magnetic resonance spectroscopy. A case of advanced prostatic cancer with metastatic chest wall tumor].

The response of advanced prostatic cancer with metastatic chest wall tumor to high-dose diethylstilbestrol diphosphate (DESP) therapy was monitored by in vivo 31P magnetic resonance spectroscopy (31P MRS) study. A eighty-three year old man with Stage D2 prostatic cancer had been treated with chlormadinone acetate and cyclophosphamide since 1984. He was admitted to our hospital with a chest wall tumor and anemia on May 9, 1992. The elevated PAP, PSA and gamma-Sm levels were also observed. Needle biopsy of the tumor revealed poorly differentiated adenocarcinoma metastatic from the prostatic cancer. The patient received 500 mg of DESP by DIV daily for 10 days, and the tumor was reduced by 54% clinically. The abnormal PAP, PSA and gamma-Sm levels returned to almost normal range by three weeks after the initiation of high-dose DESP therapy, and regression of the tumor was confirmed by the MRI. After the first administration of DESP, the MR spectra of the chest wall tumor showed elevated peaks of phosphomonoesters and phosphodiesters. These substances are related to the membrane metabolism and their increase represents the membranous degeneration of tumor cells. The same changes continued consecuitively for three weeks, and corresponded with the regression of the tumor. In conclusion, these results suggest that in vivo 31P MRS of malignant tumors can be useful for evaluating early response to therapy prior to other clinical examinations.

[Small cell carcinoma of urinary bladder. A case report].

A 57-year-old male patient was admitted because of a severe lumbar pain and gross hematuria. The rectal examination revealed a fist-sized soft tissue mass in the small pelvic space. A huge non-papillary tumor, which occupied the intravesical space, was found on cystoscopic examination. CEA IAP, TPA, CA19-9 and NSE were abnormally elevated in the serum. The pelvic CT scan shown an enormous polypoid tumor arising from the anterior vesical wall, while no abnormal lesion was found in the head, neck, chest and abdominal CT scans. The bone scintigraphy revealed multiple abnormal accumulations. The transurethral biopsy of the tumor was carried out. The pathological examination revealed homogeneous and small tumor cells arranged in sheet and solid patterns, which were positive for the anti-NSE stain and anti-NF stain, but negative for Grimelius stain. The final diagnosis was small cell undifferentiated carcinoma of the urinary bladder. The patient died of cancer five months after diagnosis.