Biomedical subjects

Y Yamazaki

Publications and source records attributed to Y Yamazaki.

At least 343 records · Page 19Linked to original sources

PubMed1995

Interaction of tryptophan-182 with the retinal 9-methyl group in the L intermediate of bacteriorhodopsin.

An intense indole N-H stretching vibrational band at 3486 cm-1 in the difference Fourier transform infrared spectrum is one of the characteristic features of the L intermediate of bacteriorhodopsin [Maeda, Sasaki, Ohkita, Simpson, & Herzfeld (1992) Biochemistry 31, 12543]. This band is now assigned to tryptophan-182. The Trp182-->Phe (W182F) protein shows specific features in the difference spectrum in the visible region upon L formation, and exhibits great delay in the L-M conversion. Fourier transform infrared difference spectra further indicate that while the intensity of the C-methyl in-plane bending vibration at 1009 cm-1 is lost in the L intermediate of the wild type, its intensity remains high in the W182F protein. The intensity of the N-H stretching vibration upon L formation is diminished considerably in an artificial bacteriorhodopsin containing 9-desmethylretinal. It also exhibits delayed M formation. These results suggest that Trp182 interacts with the retinal side chain through the 9-methyl group, and thereby affects the L-to-M conversion.

Bacteriorhodopsins↗

PubMed1995

Stereoselective hydrolysis of xenobiotic esters by different cell lines from rat liver and hepatoma and its application to chiral prodrugs for designated growth suppression of cancer cells.

Stereoselectivity in the hydrolysis of racemic ethyl 2-phenylacetate derivatives by cultured cells of noncancerous cell lines from rat liver (BRL, BRL 3A, Clone 9, and ARLJ301-3), spontaneously or oncogene transformed rat liver cell lines (ARLJ301-3TR1, Anr4, Anr9-1, and Anr13-1), and cancer cell lines from rat hepatoma (H4-II-E, McARH7777, and MH1C1) and sarcoma (XC) was studied. A strong (R)-enantiomer preference was found in the hydrolysis of ethyl 2-hydroxy-(2c) and 2-methoxy-2-phenylacetate (3c) by the noncancerous and oncogene-transformed cells and an (S)-enantiomer preference for ethyl N-acylphenylalaninates with all the present cell lines. These inclinations were, however, not recognized with ethyl 2-methoxy-2-phenylpropanoate and ethyl N-difluoroacetyl- or N-trifluoroacetylphenylalaninate. Moreover, the R preference for 3c was reversed in the reaction by hepatoma cells. Thus, the stereoselectivity is influenced by both structure of acyl group and species of cell lines. The hepatoma cells were considerably different from the noncancerous or oncogene-transformed cells in stereoselectivity. This fact was consistent with the order of colony formation in soft agar cultures (index of malignancy) and the resemblance in actively stained esterase patterns in gel electrophoresis. The stereoselective hydrolysis leads to cell-specific activation of anticancer prodrugs. This has been confirmed for the first time by the stereoselectivity of Anr4 and H4-II-E cells in the hydrolysis of a chiral mustard ester, bis(2-chloroethyl)aminophenyl 2-methoxy-2-phenylacetate (14) and by the difference of IC50 values of (R)- and (S)-14 against the two cell lines.

Agar↗

PubMed1995

Diagnostic significance of serum neuron-specific enolase and myelin basic protein assay in patients with acute head injury.

BACKGROUND: Neuron-specific enolase (NSE) and myelin basic protein (MBP) in the peripheral venous blood (PVB) have been reported to be sensitive markers for judging the prognosis of patients with head injury. However, to our knowledge, the levels of NSE and MBP in the internal jugular venous blood (IJVB) have never been studied. METHODS: In 25 patients with acute head injury, blood samples were taken from the internal jugular vein and the peripheral vein at the same time before any medical or surgical procedure was performed. The levels of NSE and MBP in the both venous blood samples were measured. The time interval between injury and sampling was 1.5-8.0 hours (mean 4.3 hours). The levels of NSE and MBP in the IJVB were compared to those in the PVB. The relationship between the clinical outcome and the serum levels of those was evaluated. RESULTS: The levels of NSE and MBP in the IJVB were almost equal to those in the PVB. The levels of NSE and MBP were significantly higher in the patients who died than in those who survived. In the survivors, the levels of NSE and MBP in the IJVB were 17.6 +/- 11.4 ng/ml and 1.4 +/- 1.5 ng/ml, whereas in the patients who died, both levels were elevated to 51.3 +/- 27.3 ng/ml (p < 0.005) and to 11.3 +/- 9.5 ng/ml (p < 0.01), respectively. CONCLUSIONS: The assay of serum NSE and MBP levels provides a reliable laboratory indicator of the degree of brain damage and allows early prediction of the prognosis in patients with acute head injury.

Acute Disease↗

PubMed1995

Laparoscopic splenectomy in children. Preliminary results and comparison with the open technique.

To determine the safety and efficacy of laparoscopic splenectomy (LS) in children, a retrospective review of our preliminary experience using LS was compared to results in patients who previously underwent open splenectomy (OS). From July 1993 to January 1995, we performed eight LS procedures in six children with hereditary spherocytosis (HS) and two with immune thrombocytopenic purpura (ITP). Laparoscopic cholecystectomy was simultaneously done in one case with HS. There were 4 males and 4 females who ranged in age from 5 to 15 years--an average age of 8.8 years. Two cases in the early series required a counterincision because of bleeding. Eleven patients who previously underwent OS in our department were used to compare demographics, operative courses, and surgical outcomes. The ages, genders, diseases, body weights, and spleen weights were comparable between LS group and OS groups. The operative time for the LS group was statistically longer than for the OS group (226 +/- 24 min vs 101 +/- 8 min, P < 0.001). The estimated blood loss in the LS group was similar to that of the OS group (100 +/- 39 ml vs 73 +/- 11 ml. P = 0.97). There were no peri- or postoperative complications in two groups. The postoperative hospital stay of LS group was statistically shorter than that of the OS (6.8 +/- 0.6 days vs 10.4 +/- .05 days, P < 0.0001). LS provided better cosmesis and minimized trauma in children over OS. LS appears to be a safe and effective procedure in children, and is useful in the management of pediatric patients with HS or ITP.

Adolescent↗

PubMed1995

Experimental model of chronic tonsillar herniation associated with early stage syringomyelia.

This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8-14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n = 6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extra-cellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n = 4) and those rats without tonsillar herniation (n = 4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.

Animals↗

PubMed1995

A direct involvement of the central nervous system in hypophagia and inhibition of respiratory rate in rats after treatment with O,O,S-trimethyl phosphorothioate.

O,O,S-Trimethyl phosphorothioate (OOS-TMP) is known to induce unique symptoms, which are characterized by hypophagia, progressive weight loss, and hypothermia. To determine whether there is the possibility of a causal relationship between these toxic symptoms and a direct action of OOS-TMP on the central nervous system, we investigated the development of these symptoms in Fischer 344 female rats after oral or intracerebral treatment with OOS-TMP. Oral administration of OOS-TMP at 20 mg/kg induced marked hypophagia, progressive weight loss and hypothermia. Moreover, inhibition of respiratory rate was observed immediately after treatment. It lasts during the entire experimental period. Profound hypothermia below 34 degrees C was observed more frequently in the rats, which became hypercapnic (PaCO2 > or = 50 mmHg). In contrast, administration of OOS-TMP at 20 mg/kg (as much as the oral dose) into the cerebral lateral ventricle succeeded in inducing hypophagia, progressive weight loss and lowered respiratory rates. On the other hand, by this route of administration, OOS-TMP at 20 mg/kg failed to induce hypothermia, hypercapnia and lung injury. The present results suggest that hypophagia and inhibitions of respiratory rate are attributable to the direct action of OOS-TMP on the central nervous system, while other symptoms are associated with lung injury.

Administration, Oral↗

PubMed1995

Detection of major and minor bcr/abl fusion gene transcripts in a patient with acute undifferentiated leukemia secondary to treatment with an alkylating agent.

In this paper we describe a patient with bcr/abl positive acute undifferentiated leukemia (AUL) derived from acquired sideroblastic anemia secondary to ifosphamide treatment given for the preceding non-Hodgkin lymphoma of the lung. Cytogenetically, Philadelphia chromosome was not detected through the whole course in this patient, and multiple chromosomal abnormalities including 5q- and monosomy 7 were found at the stage of sideroblastic anemia. The reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed no bcr/abl fusion transcript at the diagnosis of malignant lymphoma. The mRNA encoding the major bcr/abl fusion protein then appeared in the stage of sideroblastic anemia. Finally, the mRNA encoding both major and minor bcr/abl was detected in the stage of AUL transformation. MLL gene rearrangement was not found by RT-PCR analysis at any stage of the disorder. These results may be direct evidence for the induction of the bcr/abl fusion gene by treatment with an alkylating agent (ifosphamide).

Acute Disease↗

PubMed1995

Glycemic control, growth and complications in children with insulin-dependent diabetes mellitus--a study of children enrolled in a Summer camp program for diabetics in Kinki district, Japan.

The influence of glycemic control on growth and on the development of complications in diabetic children was studied. The subjects of the study were 107 children with insulin-dependent diabetes mellitus (IDDM), who were enrolled in a Summer camp program for diabetic children in Kinki District, Japan from 1972 to 1990, and who had at least three determinations of HbA1 during the observation period. Many of the children had high mean levels of HbA1, regardless of age. The height and weight were below the standards for the respective ages in many children, indicating the retardation of growth. However, S.D. scores for height and weight and other physical indices were not related to the mean levels of HbA1. By contrast, the prevalence of diabetic retinopathy was related to an elevated mean level of HbA1, but that of albuminuria was not. Serum cholesterol levels were higher in children with higher mean levels of HbA1, but serum triglycerides appeared not to be related to glycemic control. The incidence of retinopathy during the observation period closely related to the degree of the mean levels of HbA1, but that of albuminuria did not.

Adolescent↗

PubMed1995

Muscle activation in the elbow-forearm complex during rapid elbow extension.

Normal human subjects performed extensions of the elbow from an initial position to a visually defined target as rapidly and accurately as possible at different angular amplitudes (9 degrees-54 degrees) and at a constant amplitude (36 degrees) under various additional instructions. Joint angle, angular acceleration, and electromyograms (EMGs) from agonist (triceps lateralis), antagonist (biceps), and antebrachial muscles were recorded. EMGs of the antagonistic muscles showed reciprocal activation of the first triceps, and then the biceps, which was followed by the second triceps activation and coactivation of both muscles. Movement amplitude changed the reciprocal activation, whereas the coactivation was unaltered. Additional instructions changed the coactivation in amplitude, initiation, and termination, whereas the reciprocal activation was relatively preserved. Under these conditions, EMGs of antebrachial muscles were always linked with the coactivation in amplitude and timing but not with the reciprocal activation. The linkage suggests that antebrachial muscle activation serves as an indicator of the coactivation. From the indicator, we infer that the coactivation initiates from the beginning of the rapid movements and changes during the dynamic movement phase.

Adolescent↗

PubMed1995

Latent tarsal tunnel syndrome with the provocation of flexor spasms in a paraplegic person. Case report.

A 71-year-old paraplegic woman presented with a complaint of insomnia caused by severe flexor spasms of the lower limbs at night, aggravated for a few hours by taking hot baths. Lidocaine injection of the tarsal tunnel diminished the flexor-withdrawal reflex, which was easily elicited by light pinching or sustained compression over the tarsal tunnel, and strongly suggested the existence of the tarsal tunnel syndrome. Surgical decompression of the tarsal tunnel significantly reduced the flexor spasms both in terms of frequency and of duration.

Aged↗

PubMed1995

Ca(2+)-dependent enhancement of [3H]dopamine uptake in rat striatum: possible involvement of calmodulin-dependent kinases.

We studied effects of Ca2+ in the incubation medium on [3H]dopamine ([3H]DA) uptake by rat striatal synaptosomes. Both the duration of the preincubation period with Ca2+ (0-30 min) and Ca2+ concentration (0-10 mM) in Krebs-Ringer medium affected [3H]DA uptake by the synaptosomes. The increase was maximal at a concentration of 1 mM Ca2+ after a 10-min preincubation (2.4 times larger than the uptake measured without preincubation), which reflected an increase in Vmax of the [3H]DA uptake process. On the other hand, [3H]DA uptake decreased rapidly after addition of ionomycin in the presence of 1 mM Ca2+. The Ca(2+)-dependent enhancement of the uptake was still maintained after washing synaptosomes with Ca(2+)-free medium following preincubation with 1 mM Ca2+. Protein kinase C inhibitors did not affect apparently Ca(2+)-dependent enhancement of the uptake, whereas 1(-)[N,O-bis(1,5-isoquinolinesulfonyl)-N-methyl-L- tyrosyl]-4-phenylpiperazine (KN-62; a Ca2+/calmodulin-dependent kinase II inhibitor) and wortmannin (a myosin light chain kinase inhibitor) significantly reduced it. Inhibitory effects of KN-62 and wortmannin appeared to be additive. N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7; a calmodulin antagonist) also remarkably inhibited the enhancement. These results suggest that Ca(2+)-dependent enhancement of [3H]DA uptake is mediated by activation of calmodulin-dependent protein kinases.

Animals↗

PubMed1995

Inhibitory effect of probucol on nephrotoxicity induced by ferric nitrilotriacetate (Fe-NTA) in rats.

Effects of dietary probucol on renal damage induced by a renal carcinogen, ferric nitrilotriacetate (Fe-NTA), in male Wistar rats were quantitatively investigated with a computer-mediated image analyzer. The kidneys of rats fed a 1% probucol diet were protected from necrosis and lipid peroxidation induced by a single i.p. treatment with Fe-NTA solution at 5 mg Fe/kg body wt and were significantly resistant to a higher dose. For the parameter of lipid peroxidation, Schiff's staining method was utilized to demonstrate the extent of formation of aldehydes, products of lipid peroxidation. Thus following injection of Fe-NTA solution at 10 mg Fe/kg body wt the average areas of tubular necrosis were 85.8% versus 56.9% and the positive areas for Schiff's staining were 15.3% versus 5.6% in the renal cortices of rats fed control of 1% probucol diets respectively. These results indicate that probucol provides protection against Fe-NTA-induced nephrotoxicity through its antioxidant properties. In addition to being a cholesterol-lowering drug, useful for the control of hypercholesterolemia, probucol may therefore be beneficial for prevention and treatment of various pathogenic processes including those leading to carcinogenesis.

Animals↗

PubMed1995

Inhibitory effect of probucol on benzo[a]pyrene induced lung tumorigenesis.

The effects of probucol, a clinically used cholesterol lowering and antioxidant drug, on benzo[a]pyrene (B[a]P) induced pulmonary and forestomach tumorigenesis as well as induction of colonic aberrant crypt foci (ACF) in female A/J mice was investigated. Diet containing 1% probucol fed prior to, during and after 8 bi-weekly 1 mg/mouse oral intubations of B[a]P, reduced the number of pulmonary adenomas by 52% (P < 0.001) and the number of forestomach tumors by 31%. The 0.06% probucol diet also resulted in decreased tumor formation but the differences did not reach statistical significance. Both probucol diets significantly reduced the numbers of large ACF, putative preneoplastic lesions of the colon mucosa, but showed no effects on the total numbers of ACF. The results of this study suggest that probucol may also be useful as a chemopreventive agent, in addition to being a cholesterol lowering and anti-atherogenic drug with low toxicity.

Animals↗

PubMed1995

ABO incompatible kidney transplantation in children.

We have performed 7 pediatric kidney transplantations from living related donors of ABO incompatibility. All patients preoperatively underwent plasmapheresis with or without immunoadsorption to reduce anti-A and/or anti-B antibodies. Immunosuppression initially consisted of methylprednisolone, cyclosporine, azathioprine, antilymphocyte globulin and deoxyspergualin. At transplantation splenectomy was simultaneously performed in all patients. Median followup is 44 months (range 31 to 58). Patient and graft survival rates are 100% to date. There were no uncontrollable vascular rejection episodes, and post-transplant anti-A and/or anti-B antibody titers were always less than 1:32. Transplantation across the ABO blood barrier remains challenging today. However, our small series clearly shows that the preoperative reduction of ABO antibody, simultaneous splenectomy and strict immunosuppressive therapy cause successful long-term results in children.

ABO Blood-Group System↗

PubMed1995

Quantitative detection of ultraviolet light-induced photoproducts in mouse skin by immunohistochemistry.

UVB-induced cyclobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4)photoproducts [(6-4)photoproducts] in mouse skin DNA were quantitatively measured using an immunohistochemical approach with a computer-aided color image analyzer. The skins of the C3H/HeN mice were irradiated with ultraviolet B (UV-B, 280-320 nm), and processed to give conventional formalin-fixed, paraffin-embedded histologic sections. Routine immunohistochemistry clearly demonstrated a dose-dependent induction of both photoproducts. CPDs were detectable at doses > or = 125 J/m2, while for (6-4)photoproducts, the minimal dose at which they were detectable was 250 J/m2 in the present study. A time course study showed that the repair of (6-4)photoproducts was more rapid than that of CPDs, and that epidermal cells had a higher capacity for their removal than dermal cells. About half of the (6-4)photoproducts were excised within the first 24 h after the irradiation, and the process was essentially complete by 72 h. In contrast, there was no apparent removal (less than 10%) of CPDs in the first 24 h and they only completely disappeared from the epidermal cells at 120 h after irradiation. The effect of DNA dilution due to increased turnover of epidermal cells after UV-B irradiation was evaluated by quantitative immunohistochemical measurement of the time course of bromodeoxy-uridine (BrdUrd) incorporated into nuclei at 2 days post irradiation when the proliferation reaches a peak. The removal of photoproducts was more marked than the decrease in BrdUrd staining. Our results suggest that mouse skin cells can repair both (6-4)photoproducts and CPDs, but with considerably lower efficiency, especially in the latter case, then human or monkey skin cells.

Animals↗

PubMed1995

Salivary and blood lactate after supramaximal exercise in sprinters and long-distance runners.

This investigation examined the reproducibility of salivary lactate measurement in long-distance runners following a 3000-m run and compared the salivary and blood lactate concentrations in sprinters and long-distance runners following a 400-m run. There was no significant difference in salivary and blood lactate between the first and second 3000-m run test. The peak salivary and blood lactate following a 400-m run was higher in sprinters than in long-distance runners. There was a significant relationship between the peak lactate of saliva and that of blood following a 400-m run. The results showed that the salivary lactate following exercise was reproducible and the salivary lactate concentration may serve as a relevant indicator in determining which have a higher lactate production.

Humans↗

PubMed1995

Comparison of flow velocity of ophthalmic artery between primary open angle glaucoma and normal tension glaucoma.

AIMS: This study describes an investigation of the relation between the change of intraocular circulatory dynamics and visual field defect between primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). METHODS: The method was to determine the blood flow velocity of the ophthalmic artery using colour Doppler imaging and quantitative peak systolic flow velocity, mean envelope velocity, end diastolic velocity, and Pourcelot resistivity index (RI) were determined. The visual field was examined using program 30-2 of the Humphrey field analyser: the mean deviation (MD) and corrected pattern standard deviation (CPSD) were calculated as indices for visual field defects. There were 25 patients with POAG and 25 patients with NTG. RESULTS: There were no significant differences in all the four indices of the ophthalmic arterial flow and in both of visual field indices between patients with POAG and those with NTG. However, NTG patients alone showed a statistically significant correlation between RI and MD. CONCLUSION: The results suggest the vascular resistance of the ophthalmic artery may be associated with the development of visual field defect in NTG patients.

Blood Flow Velocity↗

PubMed1995

Cholecystokinin-A specific antagonism of KSG-504 to cholecystokinin receptor binding and pancreatic secretion in mammals.

The effects of KSG-504 ((S)-arginium (R)-4-[-N-(3-methoxypropyl)-N-pentylcarbamoyl]-5-(2- naphthylsulfonyl) pentanoate monohydrate), a new cholecystokinin (CCK)-receptor antagonist, on 125I-CCK-8 binding to rat pancreatic, canine gallbladder and guinea pig cerebrocortical membranes and the pancreatic amylase release from isolated rat acini stimulated by several kinds of secretagogues, including CCK, were investigated. The 125I-CCK-8 saturation experiment showed that pancreatic, gallbladder and cerebrocortical CCK receptors had a single high affinity binding component with dissociation constants (Kd) of 0.18, 0.31 and 0.88 nM, respectively. The maximum numbers of specific binding sites (Bmax) in these membranes were 1012, 52 and 20 fmol/mg protein, respectively. KSG-504 and CCK-8 displaced specific 125I-CCK-8 binding to CCK receptors in all membrane preparations in a competitive manner. The affinity of KSG-504 for pancreatic (Ki = 173 nM) and gallbladder (Ki = 283 nM) CCK receptors were > 3 orders of magnitude higher than its affinity for cerebrocortical CCK receptors. KSG-504 also inhibited 125I-gastrin-I binding to guinea pig gastric glands, but the IC50 value (18.2 microM) was apparently much higher. CCK-8-stimulated amylase release from isolated pancreatic acini of rats was antagonized by KSG-504 in a concentration-dependent manner. KSG-504 did not affect amylase release stimulated by secretagogues such as gastrin-releasing peptide, carbachol, vasoactive intestinal peptide and A23187. These results indicate that KSG-504 acts as a CCK-A-receptor-specific antagonist in the pancreas and gallbladder.

Amylases↗