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Biomedical subjects

M Nakano

Publications and source records attributed to M Nakano.

At least 1,009 records · Page 56Linked to original sources
PubMed1987

Poly(hydroxy acids) in drug delivery.

Poly(hydroxy acids) so far have been examined for use in drug delivery in limited number, while the advantageous use of the polymers has been recognized due to their biodegradability and biocompatibility. Homo- and copolymers of lactic acid and glycolic acid have been studied in drug delivery by many workers, while homo- and copolymers of epsilon-caprolactone have been studied by only one group of workers. Although poly-hydroxybutyric acid had been found to be a naturally occurring polymer, examination as to the use of the polymer in drug delivery is rather recent and reports are still limited. In the present article, the use of poly(hydroxy acids) including homo- and copolymers of lactic acid and glycolic acid, polycaprolactone, and poly-beta-hydroxybutyric acid in drug delivery is reviewed. Physicochemical properties, biodegradability, and biocompatibility of the polymers, and evaluations in vitro and in vivo of specific dosage forms using the polymers, are included. The most recent work in our laboratories on the use of polyactic acid and poly-beta-hydroxybutyric acid is also included.

Biocompatible Materials↗
PubMed1987

Fractionation of glycoproteins from porcine zonae pellucidae into three families by high-performance liquid chromatography.

The glycoproteins of porcine zonae pellucidae were fractionated into three families (PZP1-3) by high-performance liquid chromatography on a gel filtration column. Their molecular weights were estimated to be 164K for PZP1, 99K for PZP2, and 55K for PZP3; and they were present in an approximate weight ratio of protein moiety of 2:3:18, respectively. Differences in carbohydrate composition position between them were found, although their amino acid compositions were similar to each other. CD spectra showed that the three families had an almost identical secondary structure of the helical form in the presence of SDS. In PBS without SDS, they had different secondary structures, predominantly in the beta-form, and probably different tertiary structures.

Amino Acids↗
PubMed1987

Solubilization of porcine zonae pellucidae by trypsin and pronase.

The porcine zona pellucida was dissolved with difficulty by trypsin in isotonic solution, whereas it was efficiently dissolved by pronase. A structural change of the zona was induced in hypotonic solution, resulting in acceleration of dissolution by these proteases. The solubilization rate of three families (PZP1-3) of zona protein by both enzymes was analyzed by HPLC. In hypotonic solution, PZP1 was solubilized first, followed by PZP2; and PZP3 was then finally released. In isotonic solution, PZP1 and PZP2 were also solubilized faster than PZP3, which was almost completely resistant to trypsin, showing that the solubilization of the zona depended on that of PZP3. Noticeably, high molecular weight products were produced as the proteolytic hydrolysis proceeded in PBS. Circular dichroic spectra and electrophoretograms of the tryptic hydrolysates showed that the zona may have a regular supramolecular structure.

Animals↗
PubMed1987

Prognostic significance of pancreatic tumor regression after intraoperative radiotherapy.

Tumor volume measurement using tumor-margin clipping radiography was performed for estimating tumor regression of eight pancreatic adenocarcinomas treated with intraoperative electron irradiation. Half of the tumors regressed exponentially from the first day of treatment, but the other half increased slightly within the first week, after which volume reduction occurred. The volume-halving time was calculated from the regression curve. A wide distribution of volume-halving times as well as initial tumor volumes was seen in all patients. No correlation was found between these variables, but the former correlated well with survival time (r2 = 0.80). This well-known technique may offer a chance to foresee the prognosis of the disease by determining the volume-halving time.

Adenocarcinoma↗
PubMed1987

[Pharmacokinetic and clinical studies of cefuzoname in the pediatric field].

Newly developed cefuzoname (CZON) was tested in 21 children and serum and urinary concentration and urinary recovery rates were determined. To 9 cases, 3 groups of 3 cases each, CZON was given at 10, 20 or 40 mg/kg one shot intravenously, and to 12 cases, 3 groups of 5, 3, 4 cases each, 10, 20 or 40 mg/kg was drip-infused over 1 hour. To 1 case of purulent meningitis 55.6 mg/kg was given one shot intravenously and concentrations in cerebrospinal fluid (CSF) and serum were measured. In 37 pediatric patients comprising 1 with tonsillitis, 24 with pneumonia, 1 with purulent meningitis and bacteremia, 7 with urinary tract infection, and 1 each with staphylococcal scalded skin syndrome, purulent lymphadenitis, periarthritis of jaw joint, maxillary sinusitis and orbital abscess, CZON was tried at 21.6 mg/kg (mean) per dose, 3 or 4 doses daily, one shot intravenously, for 7 days (mean). The clinical efficacy and antibacterial effectiveness were investigated. Also, the side effects were investigated and clinical laboratory tests done in the 37 pediatric cases plus 6 cases in which CZON was used but which were excluded from the efficacy analysis because they did not involve infections. The following is a summary of the results: 1. To 3 groups of 3 children each, 10, 20 or 40 mg/kg of CZON was given one shot intravenously. In each case the maximum serum concentration was observed at 5 min. after injection, and mean values of 3 groups with 10, 20 and 40 mg/kg dosing were 57.1, 147.2 and 316.7 mcg/ml respectively, indicating a dose-dependent response among the 3 groups. Mean half-lives were 0.83, 1.10 and 0.79 hours for 10, 20 and 40 mg/kg groups, respectively. The 10 mg/kg and the 40 mg/kg groups showed similar half-lives but the half-life of the 20 mg/kg group was a little longer than those of the other 2. 2. CZON was drip-infused over 1 hour to a total of 12 children divided into 3 groups of 5, 3 and 4 children at dose levels of 10, 20 and 40 mg/kg, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

[Operative fiberoptic nephroureteroscope--removal of renal and upper ureteral stones].

Two types of operative fiberoptic nephroureteroscopes were developed with the cooperation of the Olympus Optical Company mainly to remove the upper urinary tract calculi. Removal of the renal and upper ureteral stones was attempted in nine cases. The ureter was dilated with olive tip, balloon and Teflon dilators alone or in combination. The combination of balloon and Teflon dilators seemed the most promising. As a result of ureteral dilation, operative fiberoptic nephroureteroscopes, 4.5 mm and 3.5 mm in diameter, could be passed into the ureter in all the cases and the stones could be visualized clearly. Four of the 7 upper ureteral stones and 1 of the 2 pelvic stones could be removed. The success ratio was 56%. The method of stone removal still requires improvement. At present, application of the operative fiberoptic nephroureteroscope is indicated for upper ureteral and renal stones less than 1.0 cm in diameter. With the improved techniques of stone removal using this fiberscope, the indications of extracorporeal shock-wave lithotripsy or percutaneous nephrolithotripsy will probably be greatly reduced in the near future.

Adult↗
PubMed1987

[Clinical evaluation of total cystectomy in patients with bladder cancer].

Thirty-one patients with bladder tumors underwent total cystectomy between April, 1969 and March, 1984. The overall five-year survival rate was 62.2%, and the ten-year survival rate was 55.0%. However, 11 of the 12 cancer deaths occurred within 5 years. The survival rate was significantly higher in G1 than in G2 or G3, but there was no significant difference between G2 and G3. The survival rate was clearly different between the superficial and deep invasive type. The group of stage pT1a or less had a significantly higher survival rate than the group of pT1b. No significant difference was detected among the groups of stage pT1b or higher. The presence of intramural lymphatic invasion (ly) may be an important prognostic factor. Pelvic lymph node metastasis was detected in 28.6% of ly 1, and in 71.4% of ly 2. The bladder cancer could be rationally classified into a superficial type and an invasive type according to the destruction of the lamina proprie. Proper adjuvant therapy should be performed for the invasive type which shows ly-positive cancer.

Adult↗
PubMed1986

Difference in activation by Tris(hydroxymethyl)aminomethane of Ca,Mg-ATPase activity between young and old rat skeletal muscles.

Fresh weight of rat skeletal muscles (M. tibialis anterior) was decreased with age. Specific activity of myosin-ATPase in the homogenate was decreased significantly at later stages of age, but not Ca,Mg-ATPase activity. The activity of Ca,Mg-ATPase was activated by high concentration (more than 75 mM) of Tris(hydroxymethyl)aminomethane. The degree of the activation was observed to be an age-related change; the activation of Ca,Mg-ATPase activity in old rats was lower than that of young rats.

Aging↗
PubMed1986

Analysis of capillary fluid flow rate by vibration on a small vessel model.

In order to estimate the direct effect of the physical vibration on the peripheral blood flow rate, we measured the water flow rate in a silicon capillary tube whose end was vibrated. Three types of vibration were added to the tube and the frequency of the vibration covered 1-2000 Hz. It is shown that the water flow rate reduces under the vibration and this reduction strongly depends on the frequency and the type of the vibration. The main reason for this dependence is shown to be as follows. The vibration stretches the tube and the average length of the tube is longer under the vibration than when under no vibration, and the average tube radius is smaller under the vibration. This causes the reduction of the flow rate under vibration. Because the stretch of the tube strongly depends on the frequency and the type of the vibration, the above dependence of the water flow rate finally appears.

Capillaries↗
PubMed1986

[Observations of capillary fluid flow rate by vibration on the small vessel model].

The vibration hazards in peripheral blood vessels as an occupational origin is caused by using pneumatic vibrating tools. In order to know that the major part of causes is whether due to the direct effects of the physical vibration or due to the effects depended on the excitations of peripheral nervous system, an model experiment was employed to estimate the direct effect of the physical vibration. In our experiments, water as fluid was used instead of blood. The silicon capillary tube as same the physical qualities and conditions as blood vessels was vibrated by oscillator. The silicon capillary tube was exposed by following three type of vibration mode to flow axis; i) sine wave of transverse vibration, ii) rectangular wave of transverse vibration, and iii) sine wave of longitudinal vibration. The range of vibration frequency covered 1-2000 Hz. The averaged acceleration by oscillating vibration and the vibration strength level were estimated about 1-200 G and 150 dB, respectively. The observed decreases of water flow rate due to vibration extremely depend on frequency. The decrease ratio of water flow rate by vibration was at maximum 12% down compare with the cases of non vibration. In these observed results by this model experiment, it should be concluded that the direct effect of the physical vibration to the blood flow was not too strong to cause the actual vibration hazards.

Blood Circulation↗
PubMed1986

A chemiluminescent probe with a Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, specific and sensitive for O2- production in phagocytizing macrophages.

When a Cypridina luciferin analog (the title compound) was added to a macrophage suspension in Hank's balanced salt solution (control), the system emitted a weak, but detectable light, which was not altered in the presence of superoxide dismutase. The same system, however, emitted a much stronger light, just after the addition of a trigger, opsonized zymosan. The luminescence was suppressed to the control level in the presence of superoxide dismutase, while it was only slightly influenced, if at all, by NaN3, a scavenger of singlet oxygen and an inhibitor of myeloperoxidase. Some other results obtained also indicate the participation of O2- in the luciferin analog-dependent luminescence in macrophages during phagocytosis.

Animals↗