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Biomedical subjects

T Maki

Publications and source records attributed to T Maki.

At least 199 records · Page 11Linked to original sources
PubMed1987

Specific tolerance to canine renal allografts following treatment with fractionated bone marrow and antilymphocyte serum.

These results suggest (1) that ALS + BM fractions can be used to promote tolerance in long-term graft survivors; (2) that the presence of apparent BM cells of donor origin in the allograft in normally functioning kidneys may be related to the mechanism of allograft prolongation, and (3) that some promise of possible specific long-term immunosuppression exists clinically.

Animals↗
PubMed1987

Multiplicity and regulation of hepatic microsomal carboxylesterases in rats.

Three isozymes of carboxylesterase were purified from rat liver microsomes by using Sephadex G-150 gel filtration, DE-52 ion exchange, and chromatofocusing column chromatographies. These isozymes each showed a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were immunologically different from each other as determined by immunochemical blotting analysis and immunochemical inhibition of catalytic activity. The three isozymes were named RH1 (molecular weight 174,000, trimer, pl 6.0), RL1 (molecular weight 61,000, monomer, pl 6.5), and RL2 (molecular weight 61,000, monomer, pl 5.5). RL1 has the highest specific activities toward p-nitrophenylacetate and malathion. Acetanilide is a rather specific substrate for RL2, whereas RH1 has the highest specific activity for butanilicaine. RL1 has the highest specific activity for the hydrolysis of long-chain acyl-CoA. To investigate the hormonal regulation of carboxylesterase activities, we have quantitated RL1, RL2, and RH1 in liver microsomes from male and female rats using a radial immunodiffusion assay. The amount of RL1 in male rats was decreased by castration but recovered to almost the level in sham-operated rat liver microsomes after treatment of the castrated rats with testosterone. Conversely, in ovariectomized female rats, the amount of RL1 was increased as compared to that in sham-operated rats, and treatment of the ovariectomized rats with estradiol tended to decrease the quantity of RL1. In all cases of sex hormone treatment, the amount of RH1 remains unclear at present. However, the amount of RL2 may be, at least in part, regulated by estrogens. On the other hand, phenobarbital treatment of male and female rats caused a significant increase in the amounts of RH1 and RL2, whereas RL1 was not affected. It was concluded that the three isozymes differ considerably from each other in response to hormone treatment, inducibility, substrate specificity, and immunological properties.

Animals↗
PubMed1986

Influence of HLA-DR phenotype and myopia on the risk of nonproliferative and proliferative diabetic retinopathy.

The relationship between HLA-DR phenotype, refractive error, and risk of both nonproliferative and proliferative diabetic retinopathy was studied among 227 insulin-dependent diabetics participating in a case-control study of diabetic retinopathy. In the absence of myopia, risk of both proliferative and nonproliferative diabetic retinopathy was increased for HLA-DR phenotypes 4/0, 3/0, and X/X (HLA susceptible) compared to HLA-DR phenotypes 3/4, 3/X, and 4/X (HLA nonsusceptible). Odds ratios equalled 11.8 and 7.4 respectively. In the presence of myopia this increased risk associated with HLA status was abolished. Myopia decreased the risk of proliferative and nonproliferative diabetic retinopathy among HLA-susceptible individuals, odds ratio equalled .09 and .09, but had no protective influence among HLA-nonsusceptible individuals.

Aged↗
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

[Age-related changes in secretion of adrenocortical steroid hormones in normal healthy men].

The influence of aging on the steroid secretory capacity of the adrenal gland was evaluated by comparing data on young (age 20 to 21 years) with elderly (age 77 to 86 years) healthy male subjects. After the administration of ACTH-Z (1 mg, im) during the treatment of dexamethasone (1 mg/day, for 2 days), blood samples were taken at time 0, 1, 2, 3, 6, 12 and 24 h. The mean basal levels of pregnenolone (P5), 17-hydroxypregnenolone (170HP5), dehydroepiandrosterone (DHEA), progesterone (P4), 17-hydroxyprogesterone (170HP4), androstenedione (A-dione) and aldosterone (Ald) gradually decreased with advance in age. Dexamethasone administration to the elderly men produced no significant fall in plasma P4 and Ald. Plasma ACTH levels after ACTH-Z administration were significantly higher in the elderly men than the comparable levels in the young men. The apparent half-life of ACTH-Z in plasma was prolonged in the elderly men. For 3 hours after ACTH-Z injection, the responses of all plasma steroids, such as P5, 170HP5, DHEA, P4, 170HP4, A-dione, Ald and cortisol (F), were significantly lower in the elderly men. When the 24-hour secretion rates of steroid hormones were compared by delta area, which indicated the increased area for 24 hours after ACTH-Z administration, the secretion rate of F showed no significant difference between the two groups, but that of DHEA was significantly low in the elderly men. The 24-hour secretion rates of P5 and P4 were not impaired and that of 170HP4 was significantly high in the elderly men. These results indicate that the steroidogenic response to ACTH decreases with aging, and that, in the elderly men, an apparent decrease in C17,20 lyase efficiency may be related in part to the decreased secretion of adrenal androgens.

17-alpha-Hydroxypregnenolone↗
PubMed1986

Contra-IL 2; a suppressor lymphokine that inhibits IL 2 activity.

Suppressive activity of culture supernatant of AS-9 (AS-9 CS), a T cell hybridoma line that was derived from fusion of BW5147 thymoma and splenic T cells of anti-lymphocyte serum-treated C3H mice, was analyzed. AS-9 CS inhibited allogeneic cytotoxic T lymphocyte (CTL) generation as well as T cell proliferation to alloantigens and mitogens, but failed to inhibit B cell response to lipopolysaccharide or growth of tumor and fibroblast cells. Although addition of AS-9 CS to the allogeneic sensitization culture as late as on day 2 of incubation resulted in maximal inhibiton of CTL generation, removal of AS-9 CS on day 3 of incubation abolished its inhibitory effect. Addition of purified IL 2 together with AS-9 CS to the allogeneic sensitization cultures only partially abrogated the suppression. Experiments with IL 2-dependent cytotoxic T cell line (CTLL) showed that AS-9 CS suppressed the IL 2-induced proliferation of CTLL. Preincubation of AS-9 CS with CTLL removed its inhibitory effect on CTL generation. These results indicate that AS-9 CS interferes with the mechanism of T cell activation by IL 2. On this basis, AS-9 CS was named contra-IL 2.

Animals↗
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

Distribution of muscle changes in experimental ischemic myopathy.

The distribution of ischemic changes was examined in the medial gastrocnemius muscle of the cat, following transient simultaneous clamping of the aorta and femoral artery. Initial changes occurred in the middle portion of the muscle, in the areas corresponding to watershed zones of the primary arteries of the muscle. The superficial layers of the muscle, the regions close to the main stem of the primary arteries, and the entire distal portion of the muscle were the most resistant to ischemic damage. These studies demonstrate that in the feline medial gastrocnemius muscle, the vascular pattern is the primary factor in determining the distribution of ischemic changes. The role of differential muscle fiber vulnerability is only secondary.

Adenosine Triphosphatases↗
PubMed1986

The effect of nutritional support on T-lymphocyte subpopulations in protein calorie malnutrition.

T-lymphocyte subpopulations were measured in the two major types of adult malnutrition, adult marasmus and kwashiorkor-like hypoalbuminemic malnutrition. The population of T-cells (T3) and the percentage of both helper (T4) and suppressor (T8) T-cells were significantly (P less than .05) decreased in patients with kwashiorkor-like hypoalbuminemic malnutrition, but did not differ from control values in patients with adult marasmus. The ratio of helper T-cell (T4), to suppressor T-cells (T8) (range 1.2-1.6) did not vary from control values in either type of malnutrition. One week of nutritional support was not associated with a significant increase in any of the T lymphocyte subpopulations in either type of malnutrition. These T-cell subpopulation changes are consistent with the greater depression of cellular immune function seen in patients with metabolic stresses associated with kwashiorkor-like hypoalbuminemic malnutrition. With the increasing frequency in which abnormalities of T-cell subpopulations are being reported in various diseases, the coexistence of kwashiorkor-like hypoalbuminemic malnutrition should be noted for its potentially confounding effect.

Adult↗
PubMed1986

Immunological characteristics of purified pancreatic islet grafts.

In a DBA/2 (H-2d) pancreatic islet-to-B6AF1 (H-2b/k.d) recipient combination, the graft survival of hand-picked islets was compared with that of "crude digested" islets that were prepared simply by collagenase digestion and Ficoll gradient separation and were contaminated with lymph nodes and vascular and ductal tissue. Islet allografts were transplanted into the renal subcapsular space of streptozotocin-induced diabetic recipients. No immunosuppression was used. All the crude digested islet allografts were acutely rejected between days 7 and 18 with a median survival time (MST) of 10.2 +/- 2.5 days. In contrast, 33% (3/9) of the purified islet allografts survived more than 100 days. Simultaneous transplantation of purified islets and contaminating tissue resulted in a shorter graft survival (MST of 15.6 +/- 3.7 days). When 5 X 10(7) donor strain spleen cells were injected i.v. at the time of transplantation, all purified islet grafts were acutely rejected within 9 days. In addition, the rejection time of the purified islet allografts was inversely correlated with the number of donor spleen cells injected. These results indicate that contaminating tissues such as lymph nodes, vascular tissue, and ductal fragments present in the crude digested islet allografts are a major stimulus for induction of an immune response resulting in acute rejection of islet allografts.

Animals↗
PubMed1986

Prolongation of renal allograft survival in antilymphocyte-serum-treated dogs by postoperative injection of density-gradient-fractionated donor bone marrow.

Posttransplant injection of fractionated donor bone marrow cells results in the prolonged survival of mouse skin allografts. In this investigation, we extended the study to the use of donor bone marrow fractionated by density-gradient centrifugation in a larger animal model, canine renal transplantation. Renal allografts were placed in outbred, histoincompatible dogs treated daily with rabbit or horse antilymphocyte serum (ALS) from days -6 to +7 relative to kidney transplantation on day 0. Fresh, unfractionated donor bone marrow (BM) or a bone marrow fraction (BM Fr3) produced by centrifugation in a discontinuous Percoll density gradient was intravenously infused into recipients on days +13 or +14. Alternatively, frozen/thawed (F/Th) BM or BM Fr3 was infused after storage at -80 degrees C for two weeks. BM Fr3 and unfractionated BM significantly (P less than 0.005) prolonged for median allograft function time (MFT) beyond the controls treated only with ALS (46 and 35 days vs. 18 days). The longer MFT with BM Fr3 was achieved with 20-40% of the unfractionated BM cell dose. In addition, BM Fr3-treated dogs exhibited a slower rate of loss of kidney function. F/Th BM was as effective as fresh BM in prolonging graft survival. A reduced mixed lymphocyte response to donor and third-party cells and markedly reduced responsiveness to Con A, PHA, and pokeweed mitogens at 30-45 days posttransplant suggested that animals were nonspecifically immunosuppressed during this period. By 60 days posttransplant, in two dogs treated with BM Fr3, the MLR to third-party cells, but not to donor cells, and the responsiveness to mitogens had returned to pre-ALS treatment values. Thus, treatment with ALS combined with fresh or F/Th BM that has been fractionated is an effective method for the prolongation of kidney allografts in dogs. The development of specific, long-term immunosuppression induced by fractionated bone marrow and success with F/Th BM in this canine renal allograft model suggests that application to human transplantation may be effective with fresh or F/Th BM fractions obtained from living-related or cadaveric donors.

Animals↗