Biomedical subjects
Publications and source records attributed to H Nagashima.
Many different types of pesticides are used extensively on fruits and vegetables. The present contribution represents an overview of the multiresidue methods of analysis of the most widely used pesticides.
In vivo and in vitro matured porcine oocytes were fertilized by subzonal sperm injection (SUZI), and their subsequent development in vitro was examined to determine whether ooplasmic incompetence is the major cause of limited developmental ability of in vitro matured/ fertilized porcine oocytes (Experiment 1). There was no significant difference in rates of fertilization (61% vs. 70%), monospermy (37% vs. 45%), and male pronuclear formation (77% vs. 61%) between in vivo and in vitro matured oocytes. Blastocyst formation rate was significantly lower for in vitro matured oocytes (11% vs. 42%; P < 0.001). Forty-six percent of in vivo matured oocytes cleaved to the 2-4 cell stage by 24 hr in culture after SUZI, compared with 3% of in vitro matured oocytes (P < 0.01). In experiment 2, in vitro development of in vitro matured oocytes with evenly and unevenly granulated cytoplasm were compared after SUZI to examine whether developmentally competent in vitro matured oocytes can be identified on the basis of morphological appearance. Most of the blastocysts obtained developed from oocytes with unevenly granulated cytoplasm (7/56 vs. 1/45; P > 0.05). Experiment 3 revealed that the proportion of oocytes with evenly granulated cytoplasm was originally low (11%) in the population of oocytes used for in vitro maturation, and it increased approximately 3-fold (36%; P < 0.001) after maturation. These results suggest that ooplasmic incompetence in porcine in vitro matured oocytes is the major cause of their limited developmental competence. Cytoplasmic maturation measured by male pronucleus formation does not directly reflect developmental competence of the oocytes. It was also shown that evenness of granulation of the cytoplasm is not a useful morphological indicator of developmental competence.
Hypotension is frequently encountered during hemodialysis (HD). One of the main factors of the HD-induced hypotension is acute reduction of circulating plasma volume by water removal, which is induced by the poor plasma refilling from the extravascular space into vessels. The determinants of plasma refilling, however, have not been clearly identified. Recently, we devised a mathematical model of water transport in HD patients, which can estimate the plasma-refilling coefficient (Kr) during HD. In the present study, we evaluated the factors determining plasma refilling by using this model. In 13 patients undergoing regular HD, the changes of Kr during HD were calculated from the model. Levels of ANP, cGMP, cAMP, endothelin, angiotensin II and vasopressin were measured before and after HD. Kr fell from 750.4 +/- 558.0 to 112.8 +/- 81.9 ml/mm Hg/h during HD. The rate of water removal during HD showed no significant correlation with the changes of Kr. Among the hormones and nucleotides measured here, plasma ANP level and cGMP were significantly correlated with Kr (r = 0.78, p < 001 and r = 0.62, p < 0.01, respectively). Our findings suggest that severe reduction in the level of serum ANP during HD, which is induced by water removal, plays some role in HD-induced hypotension through the attenuation of plasma refilling in HD patients.
During hemodialysis therapy, a large amount of water is removed from the patient's blood in a short time; however, blood pressure remains stable in most patients. As water is removed, the circulating serum proteins become more concentrated, resulting in a marked increase in the driving force which pulls water from the extravascular space into the blood vessels, by a process called plasma refilling. However, since a method for studying plasma refilling has not previously been proposed, it is not known what determines the plasma refilling capacity of hemodialysis patients. To evaluate the plasma refilling capacity of patients, we propose here a method for calculating an index of plasma refilling capacity, which we have called the plasma-refilling coefficient (Kr). In 14 patients receiving maintenance hemodialysis therapy, total serum protein was measured before hemodialysis, and hematocrits were measured hourly during hemodialysis. From the changes in the hematocrits, we estimated the changes in the circulating plasma volume and in the intracapillary oncotic pressure at each time point. The water removal rate was also measured hourly. From these values, we calculated Kr. An averaged volume of 2,692 +/- 219 ml of water was removed from each patient resulting in a decrease in the estimated circulating blood volume, while the hematocrit and the estimated intracapillary oncotic pressure increased gradually. Kr calculated after 1 h of hemodialysis varied widely between patients, 140.3-1,744.2 ml/mm Hg/h, and decreased gradually as water removal continued. The average Kr of 14 patients was 698.9 +/- 15.2 ml/mm Hg/h at the beginning of water removal, and it decreased to 405.3 +/- 75.4, 203.9 +/- 39.5, 130.2 +/- 20.5 and 93.9 +/- 14.3 each hour thereafter. The index of plasma refilling proposed in this paper is useful for examining capillary water permeability and the degree of plasma refilling in hemodialysis patients.
OBJECTIVES: This study was undertaken to examine the influence of plasma lipoprotein(a) [Lp(a)] levels on coronary endothelial vasomotor function. BACKGROUND: Epidemiologic studies have demonstrated a direct relation between elevated plasma levels of Lp(a) and increased risk of coronary artery disease. Well recognized coronary risk factors are known to affect endothelium-dependent vasomotion; however, the influence of Lp(a) on coronary vasomotor function has not been determined. METHODS: We used quantitative coronary angiography to measure left anterior descending coronary artery diameter changes produced by intracoronary acetylcholine and isosorbide dinitrate in 30 patients with angiographically normal coronary arteries. Plasma Lp(a) levels were determined with enzyme-linked immunosorbent assay. RESULTS: Vasomotor response to acetylcholine ranged from +13% to -47% in the proximal, from +23% to -53% in the middle and from +13% to -56% in the distal segment of the left anterior descending coronary artery. According to univariate linear regression analysis, Lp(a) had a significant inverse correlation with vasomotor response to acetylcholine: r = 0.47, p < 0.01 in the proximal; r = -0.61, p < 0.001 in the middle; and r = -0.52, p < 0.01 in the distal segment of the left anterior descending coronary artery. By multiple stepwise regression analysis, plasma Lp(a) was the significant predictor of vasomotion in response to acetylcholine in all tested segments (p < 0.01). CONCLUSIONS: Elevated Lp(a) levels were associated with impairment of endothelium-dependent vasodilation even when atherosclerotic lesions were not recognizable by angiography. This finding suggests that elevated plasma levels of Lp(a) cause endothelial dysfunction and may contribute in part to later development of atherosclerosis, as shown in epidemiologic studies.
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Most porcine oocytes matured and fertilized in vitro fail to develop normally due to abnormal fertilization. The aim of this study was to determine the effect of cysteamine on pronuclear formation and developmental competence in pig embryos produced in vitro. Follicular oocytes were matured in vitro with or without cysteamine in Medium 199 supplemented with sodium pyruvate, FSH, LH, 17 beta-estradiol, antibiotics, and 25% porcine follicular fluid. Matured oocytes were then inseminated for 10 h. In the first experiment, pronuclear formation was assessed immediately after the insemination period. The addition of 50 microM or 500 microM cysteamine to the maturation medium increased male pronuclear development, resulting in a higher proportion of oocytes with synchronously formed male and female pronuclei. The frequency of synchronous pronuclear formation was increased in monospermic oocytes from 10% in the control group to 43% (p < 0.001) and 45% (p < 0.001), respectively, and in polyspermic oocytes from 43% in the control group to 68% (p < 0.05) and 75% (p < 0.001), respectively. In the second experiment, development of the in-vitro produced embryos was assessed after 7 days of culture in vitro. The addition 500 microM cysteamine to the maturation medium increased the percentage of cleaving embryos developing to the 8-cell (37% vs. 16%; p < 0.001), morula (19% vs. 6%; p < 0.001), and blastocyst (12% vs. 1%; p < 0.001) stages. These results demonstrate that the addition of cysteamine to maturation medium increases synchronous pronuclear formation and normal embryonic development in porcine oocytes matured and fertilized in vitro.
Although the neuromuscular junction is the most thoroughly studied synapse of any type and has become the model of our understanding of synaptic transmission, some questions remain unanswered; e.g. there has been no direct assessment of the size of margin of safety. In this study the [Ca2+]o-dependent, quantally released acetylcholine measured by a neurochemical method, and the contraction of the mouse hemidiaphragm in response to phrenic nerve stimulation were recorded, and the effect of neomycin was studied. It was found that a much higher concentration of neomycin was needed to depress contractions, than to reduce acetylcholine release to the same extent, and that there was an inverse correlation between [Ca2+]o and the inhibitory effect of neomycin on acetylcholine release. Ninety percent of the release of acetylcholine had to be reduced by neomycin before any reduction in muscle responses could be seen. This indicates that the margin of safety is about 10. In conclusion, at the neuromuscular junction any reduction in ACh release, whatever the mechanism, first produces a reduction in the margin of safety. The nondepolarizing neuromuscular blocking agents block primarily the nicotinic receptors located on the postjunctional site. Many receptors have to be blocked before a reduction of muscle response is observed. This is probably the reason why unexpected clinical problems (e.g. recurarization) have been described when a patients has been treated with antibiotics, even though the dose of muscle relaxant injected was relatively low.
A case of recurrent hemangiopericytoma involving the torcular herophili is reported, with special reference to the reconstruction of the straight sinus with a radial artery graft. In preoperative investigations, the tumor was found invading the straight and transverse sinuses. The involved occipital superior sagittal sinus had been removed in the previous surgery. A collateral bypass was observed from the superior sagittal sinus to the straight sinus, and the veins of Rosenthal were not opacified, suggesting poor venous drainage from the deep venous system to the cavernous sinus. We considered it necessary to reconstruct the straight and right transverse sinuses to achieve total removal of the tumor. The affected sinuses were removed and were successfully reconstructed with a radial artery interposition graft between the straight and right transverse sinus. The postoperative course was good, and the bypass was patent on the postoperative angiogram. The details of the operative technique are described.
The mastoid air cell was illuminated to estimate the location of the sigmoid sinus in 12 cases of a retrosigmoid suboccipital craniotomy for cerebellopontine angle tumors. A special illuminator system was designed, and the tip of the illuminator was placed inside the external auditory canal. The posterior margin of the illuminated air cell was delineated on the outer surface of the skull after the skin flap was turned and the position of the sigmoid sinus was estimated with reference to the preoperative computed tomographic scan. The posterior margin of the mastoid air cell in an axial slice, including the internal auditory canal, usually exists within the breadth of the sigmoid sinus. A gap between the posterior margin of the mastoid air cell and the position of the sigmoid sinus was easily corrected by the computed tomographic finding. This method was found to be simple and reliable in performing the suboccipital craniotomy with safety and exactness.
The results of rotationplasty for patients with osteosarcoma around the knee joint are presented. After an average observation period of 13.3 months, there has been no local recurrence or metastasis. The ankle joints (the new knee joints) of the patients were able to support their body weight with an average range of motion of 75 degrees. All patients could walk well without crutches and without risk of the giving way phenomenon. The average rate of the functional evaluation according to the re-modified system by Enneking was 84.5% (range, 80.0-86.7%). No patient had psychological trouble in accepting the shortened and rotated extremity. The results show that rotationplasty is a useful reconstructive method for the treatment of osteosarcoma around the knee joint.
Seventy-six patients with ulnar neuropathy at the elbow were divided into 3 classes (Grades I, II, and III) according to their clinical features and the maximal motor nerve conduction velocity (MCV), and the amplitude ratios at the across-elbow segment were retrospectively analyzed. To determine the criteria for abnormality, a control study was conducted on 150 healthy volunteers ranging in age from 20 to 89 years (6 age groups). The normal value for MCV could be set for two age groups: those under 60 and those over 60 years old. The 95% confidence limit was 54m/s for the former and 50m/s for the latter. There was no statistically significant difference in the amplitude ratio among the age groups. The confidence limit was set uniformly at 0.82 (above elbow/below elbow). An abnormality in either MCV or the amplitude ratio was found in 66.7% of Grade I (recent and mild symptoms), 89.7% of Grade II (persistent symptoms), and 100% of Grade III cases (marked intrinsic muscle atrophy). Evaluation using the combination of MCV and the amplitude ratio, considering the age-related normal value, appeared to be useful in establishing a differential diagnosis of ulnar neuropathy at the elbow.
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Sixty two patients with blunt renal trauma were treated and followed in our clinic between 1976 and 1993. Immediate operation was performed in one with major laceration, 3 with ruptures and one with pedicle injury, that is, nephrectomy in 4 and partial nephrectomy in one. Expectant management with the purpose of preserving the injured kidney was performed in 33 contusions, 20 minor lacerations and 5 major lacerations, resulting in no complications. We confirm that expectant management of blunt renal trauma may be reliable if the condition of the patient is stable even in the case of rupture, and the treatment of associated injury is preferential.
Eighty cases of surgically treated syringomyelia were retrospectively reviewed. The cases were classified into following 4 types, type 1: syringomyelia with Chiari malformation (54 cases), type 2: syringomyelia with basal arachnoiditis (15 cases), type 3: syringomyelia with an obstruction of the foramen Magendie (1 case), and type 4: syringomyelia with spinal arachnoiditis (14 cases). Foramen magnum decompression (FMD) was performed in patients with type 1, in type 2 fourth ventricle-subarachnoid shunt was additionally performed. Gardner's operation was performed in patients with type 3. Syrinx-peritoneal shunt was performed in patients with type 4. Surgical procedures for syringomyelia which we selected were thought to be appropriate, based on postoperative syrinx collapse rate in MRI. However, postoperative clinical course was much different in each type of syringomyelia after the collapse of syrinx had been equally achieved. Neurological disorders were stopped in deterioration after surgery in all cases of type 1. However, motor weakness was still deteriorated in half cases of type 2, and in 60% of type 4. When clinical severity of the patients with type 1 and 2, based on the distribution of dissociated sensory loss and motor weakness, were classified into 5 grades. The rate of improvement of patient's symptoms and signs was higher in the lower grades. We concluded that a surgical treatment for syringomyelia was essentially a preventive one, therefore it should be done in early stage of disorders.
The lipid content of porcine 1-cell stage embryos was reduced (delipated) through the use of micromanipulation to remove the lipid layer formed after centrifugation. Of 94 delipated embryos chilled to 4 degrees C for 1 h at the 1-cell or 2- to 4-cell stage, 60 (64%) cleaved in culture with development to the morula-blastocyst stage, whereas all of the control embryos lysed within 24 h. Significantly more embryos developed beyond the 8-cell stage when they were chilled at the 2- to 4-cell stage compared with chilling at the 1-cell stage (44%, 20 of 45 vs. 18%, 9 of 49). Fewer embryos developed after chilling if they were only partially rather than fully delipated. Developmental rates of partially delipated embryos to the 8-cell and blastocyst stages were 33% (13 of 40) and 8% (3 of 40), rates significantly (p < 0.001 and 0.05) lower than the rate for fully delipated embryos (73%, 38 of 52 and 27%, 14 of 52, respectively). The in vitro developmental competence of the unchilled fully delipated embryos was comparable to that of intact zygotes (cleavage: 94%, 45 of 48 vs. 87%, 26 of 30; > or = blastocyst: 40%, 19 of 48 vs. 57%, 17 of 30). These data demonstrate that the sensitivity of porcine embryos to chilling is related to their high lipid content and that they can become tolerant to chilling if their lipid content is reduced.
BACKGROUND AND PURPOSE: The purpose of this study was to investigate the behavioral changes, in particular retention of memory, after focal cerebral ischemia in rats. METHODS: Ischemia was produced by permanent occlusion of the left middle cerebral artery (MCA). For quantitative behavioral analysis, one-trial passive avoidance response and active avoidance response with the discrete lever-press avoidance procedure were observed. One group of animals was trained once to learn the passive avoidance task 1 day before surgery. The response latency was examined 4 and 14 days after surgery. The second group was trained to learn the active avoidance task for 2 weeks before surgery. The avoidance rate was examined 3 and 14 days after surgery. RESULTS: The MCA-occluded group showed significant failure of memory retention in both of these tasks (P < .01). The nonoperated group and sham-operated group showed no definite memory failure. CONCLUSIONS: Retention of memory in the passive avoidance response and the active avoidance response was disturbed after left MCA occlusion in the rat. These results strongly suggest that this model can be used to assess memory disturbance after focal cerebral ischemia.
Isosteric side chain analogs of 3a were synthesized and tested for inhibitory activities towards 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase and upon cholesterol production in Hep G2 cells and in mouse liver. It became clear that the lipophilic substituent on the aromatic ring and the terminal hydrophilic group in the side chain were important in the enhancement of activity. 4-[2-(3-n-Hexyloxyphenyl)ethyl]-3-hydroxy-methyl-2-oxetanone (5a) showed equivalent inhibitory activity in vivo to that of 1233A.