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Biomedical subjects

R Goto

Publications and source records attributed to R Goto.

At least 19 recordsLinked to original sources
PubMed1992

Effects of alkyl glycosides incorporated into liposomes prepared from synthetic amphiphiles on their tissue distribution in Ehrlich solid tumor-bearing mice.

A study of the effects of alkyl glycosides incorporated into synthetic liposomes with respect to their stability, their in vivo distribution in Ehrlich solid tumor-bearing mice and their in vitro interaction with liver cells was undertaken. The synthetic liposomes were prepared from N,N-didodecyl-N alpha-[6-(trimethylammonio)hexanoyl]-L-alaninamide bromide (N+C5Ala2C12) and labeled with 99mTc. n-Dodecyl glucoside (DG) and n-dodecyl sucrose (DS) were used as alkyl glycosides. The stability was hardly changed by incorporation of alkyl glycosides into the liposomes in saline and serum. The uptake of DG- and DS-modified N+C5Ala2C12 liposomes decreased in liver and spleen compared with that of unmodified N+C5Ala2C12 liposomes, resulting in an increase in blood and other tissues such as tumor, duodenum and kidney, where the DS-modified N+C5Ala2C12 liposomes had a marked tendency. It was observed with electron micrographs that the size of N+C5Ala2C12 liposomes became small by incorporation of alkyl glycoside. The smaller N+C5Ala2C12 liposomes were found to result in the lower uptake in liver. The interaction of the liposomes with liver cells in vitro indicated that both DG- and DS-modified liposomes had a low affinity for liver cells compared with the unmodified liposomes and the extent of interaction of the DS-modified liposomes was weaker than that of the DG-modified liposomes.

Alkylation↗
PubMed1992

Perioperative complement activation in neonates under halothane or fentanyl anaesthesia.

We investigated perioperative changes in complement activation in 18 neonates undergoing elective abdominal surgery with or without thoracotomy by measuring plasma concentrations of C3a and C5a, and leucocyte counts in peripheral blood. The 18 neonates, ranging in age from 1 to 17 days, were randomly divided into two groups according to type of anaesthetic procedures; the "halothane group" consisted of nine neonates in whom general anaesthesia was maintained with halothane and nitrous oxide (N2O) in oxygen, while the "fentanyl group" consisted of nine neonates in whom general anaesthesia was maintained with fentanyl and N2O in oxygen. Plasma C3a and C5a concentrations were higher in the fentanyl group than in the halothane group during the perioperative period. We have demonstrated that abdominal surgical trauma caused complement activation even in neonates undergoing the fentanyl rather than the halothane anaesthesia. Further studies are required to elucidate the precise mechanisms and the clinical implication of perioperative complement activation in neonates.

Abdomen↗
PubMed1992

[Significance of normal oral flora, particularly group oral streptococci as defense mechanism against infection in healthy individuals (normal defense mechanism by oral Streptococcus group)].

The alpha-streptococci, consisted of normal oral flora mainly, with inhibitory activity against pathogenic microbes in healthy individuals was investigated by group A Streptococcus (indicator strain 6-22 nonmucoid T-12). Rate of alpha-streptococci with inhibitory activity against group A Streptococcus was increased as aging, and the rate in pre-school children was higher than that in school children. These results suggested that more than 90% of the tested alpha-streptococci with strong inhibitory activities (S. salivarius) against indicator strain had inhibitory activities against group A Streptococcus (mucoid T-6), H. influenzae, S. pneumoniae, group C Streptococcus, and from 40% to 70% of the tested strains had also inhibitory activities against other pathogens. As there were many strains of alpha-streptococci with inhibitory activities against pathogens, that usually detected in the upper respiratory infection, the problem on the strains in the future will explain significance of the defense mechanism against upper respiratory infection and this can be applied clinically.

Adolescent↗
PubMed1992

[Growth inhibitory activity of clinical isolates of Pseudomonas aeruginosa against Staphylococcus aureus (MRSA and MSSA)].

Anti staphylococcal activity by clinical isolates of Pseudomonas aeruginosa was tested by the reversed agar plate and the filter paper stamp methods. Almost 40% of Pseudomonas aeruginosa inhibited the growth of both Methicillin resistant Staphylococcus aureus (MRSA) and Methicillin sensitive Staphylococcus aureus (MSSA). Green pigment (Pyocyanin) produced strains showed a strong inhibitory effect against MRSA and MSSA respectively. But some other pigment (Yellow, Red) strains also showed anti staphylococcal activity. These data suggest the colonization of Pseudomonas aeruginosa with anti staphylococcal activity may not be eradicated by the anti pseudomonic antibiotics.

Antibiosis↗
PubMed1992

Effects of mexiletine on the haemodynamic responses to tracheal intubation.

The efficacy of intravenous mexiletine in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation was studied in 30 normotensive patients undergoing elective surgery. The patients were randomly allocated to one of three treatment groups: saline (n = 10); 2 mg/kg mexiletine (n = 10); and 3 mg/kg mexiletine (n = 10). The placebo/mexiletine was administered immediately before induction of anaesthesia using 5 mg/kg thiopentone and tracheal intubation was facilitated with 0.2 mg/kg vecuronium; laryngoscopy lasting 30 s was attempted 2 min after induction of anaesthesia. All groups showed a significant (P less than 0.05) increase in mean arterial pressure and heart rate associated with tracheal intubation. The increase in mean arterial pressure was significantly (P less than 0.05) smaller in patients receiving 3 mg/kg mexiletine compared with those receiving either saline or 2 mg/kg mexiletine. There was no significant attenuation in heart rate in either of the mexiletine treatment groups compared with the saline group. It is concluded that 3 mg/kg mexiletine given intravenously provides a simple and effective method for attenuating the pressor response to laryngoscopy and tracheal intubation.

Adult↗
PubMed1992

[Coronary artery spasm during coronary artery bypass surgery].

We report two cases of coronary artery spasm during coronary artery bypass surgery. As one of the complications during cardiac surgeries, coronary vasoconstriction occurs mainly after coming off cardiopulmonary bypass. The factors responsible for the spasm include high endogenous catecholamine levels due to inadequate anesthesia and hypothermia, exogenous catecholamines for circulatory support, various chemical mediators and combination of these factors. Coronary artery spasm was suspected strongly because of sudden ischemic change in electrocardiography and simultaneous aggravation of circulatory parameters, which improved immediately after direct injection of coronary vasodilators into vein graft. This method, popular in coronary angiography and catheterization, is effective for release of coronary-artery spasm observed particularly after cardiopulmonary bypass. Then mechanical circulatory assist is readily available to treat possible systemic side effect of the vasodilators.

Coronary Artery Bypass↗
PubMed1991

Immunoglobulin variable-region-like domains of diverse sequence within the major histocompatibility complex of the chicken.

The highly polymorphic B-G antigens are considered to be part of the major histocompatibility complex (MHC) of the chicken, the B system of histocompatibility, because they are encoded in a family of genes tightly linked with the genes encoding MHC class I and class II antigens. To better understand these unusual MHC antigens, full-length B-G cDNA clones were isolated from B21 embryonic erythroid cell cDNA library, restriction-mapped, and sequenced. Five transcript types were identified. Analysis of the deduced amino acid sequences suggests that the B-G polypeptides are composed of single extracellular domains that resemble immunoglobulin domains of the variable-region (V) type, single membrane-spanning domains typical of integral membrane proteins, and long cytoplasmic tails. Sequence diversity among the five transcript types was found in all domains, notably including the B-G immunoglobulin V-like domains. The cytoplasmic tails of the B-G antigens are made up entirely of units of seven amino acid residues (heptads) that are typical of an alpha-helical coiled-coil conformation. The heptads vary in number and sequence between the different transcripts. The presence within B-G polypeptides of polymorphic immunoglobulin V-like domains warrants further investigations to determine the degree and nature of variability within this domain in these unusual MHC antigens.

Amino Acid Sequence↗
PubMed1991

Myocardial oedema and ventricular function after cardioplegia with added mannitol.

Myocardial oedema may contribute to the impaired myocardial performance which commonly follows open heart surgery with cardioplegia-induced cardiac arrest. The rate of oedema formation during crystalloid cardioplegia and the relation of this to changes in ventricular compliance and ventricular function following reperfusion were studied using an isolated rabbit heart preparation. Myocardial tissue water content increased during cardioplegic arrest and the water content prior to reperfusion demonstrated an inverse correlation with ventricular function after reperfusion. In further studies the effect of adding mannitol to a standard crystalloid cardioplegic solution was investigated. The preparations were divided into two groups: nine were administered a standard cardioplegic solution (Plegisol*) (control group) and a further eight were administered the same solution mixed with mannitol to adjust the osmotic pressure to 360 mOsmol.L-3 (mannitol group). The mannitol group demonstrated less increase in RV water content and superior LV dP/dtmax following reperfusion. It is concluded that mannitol enhances protection of the myocardium during cardioplegic cardiac arrest.

Animals↗
PubMed1991

Effects of trimetaphan on the cardiovascular response to tracheal intubation.

In three groups of 10 patients, we have studied the effect on the cardiovascular responses to laryngoscopy and intubation of bolus doses of saline or trimetaphan 0.05 mg kg-1 or 0.1 mg kg-1 given 1.75 min before the start of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were less in trimetaphan-treated patients compared with those of the control group (P less than 0.05). There was no significant difference in heart rate following tracheal intubation between the three groups. These data suggest that trimetaphan may be used as a supplement during induction, to attenuate the hypertensive response associated with laryngoscopy and tracheal intubation.

Anesthesia, General↗
PubMed1991

Effects of adenosine triphosphate on the cardiovascular response to tracheal intubation.

Laryngoscopy and tracheal intubation often cause hypertension and tachycardia, which may be exaggerated during rapid-sequence induction of anaesthesia. The efficacy of adenosine triphosphate (ATP) in attenuating this response was studied in patients receiving ATP 0.05 mg kg-1 or 0.1 mg kg-1 simultaneously with the start of laryngoscopy. These data were compared with those for a control group receiving saline. Each group consisted of 10 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1 i.v. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increase after tracheal intubation were reduced in ATP-treated patients compared with those of the control group (P less than 0.05). The data suggest that a bolus injection of ATP is a simple, practical and effective method for attenuating the hypertensive response to laryngoscopy and tracheal intubation.

Adenosine Triphosphate↗
PubMed1991

Effects of pindolol on the cardiovascular response to tracheal intubation.

Laryngoscopy and tracheal intubation often cause hypertension, tachycardia and arrhythmias, which may be exaggerated during rapid-sequence induction of anaesthesia. We have studied the efficacy of pindolol in attenuating the cardiovascular responses to laryngoscopy and intubation in patients receiving pindolol 2 micrograms kg-1 or 4 micrograms kg-1 3 min before induction of anaesthesia in a double-blind design. The data were compared with those in a control group receiving saline. Each group consisted of 10 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. Patients receiving saline showed a significant increase in mean arterial pressure and heart rate associated with tracheal intubation. These increases after tracheal intubation were reduced in pindolol 4 micrograms kg-1 treated patients compared with those in the control group (P less than 0.05). Pindolol 2 micrograms kg-1 attenuated tachycardia in response to intubation but did not affect hypertension. These data suggest that a bolus injection of pindolol 4 micrograms kg-1 is a simple, practical and effective method for attenuating cardiovascular responses to laryngoscopy and tracheal intubation.

Adult↗
PubMed1991

Effects of exogenous intravenous glucose on plasma glucose and lipid homeostasis in anesthetized children.

Whether or not intravenous glucose administration during pediatric anesthesia is necessary remains a controversial issue. The current study was designed to investigate the effect of glucose infusion on concentrations of plasma glucose, nonesterified fatty acids (NEFA), triglycerides, ketone bodies, and insulin and to determine whether the use of solutions containing less than 5% glucose would maintain physiologic plasma glucose concentrations during tympanoplasty lasting about 6 h. Forty-five children aged between 1.5 and 9 yr were divided randomly into three groups of 15 patients each to receive the following intravenous solutions: LR groups, lactated Ringer's solution (LR) alone; D2LR group, 2% glucose in LR; and D5LR group, 5% glucose in LR. All fluids were infused at a rate of 6 ml.kg-1.h-1 until 1 h after anesthesia. In the LR group, the plasma glucose concentrations remained unchanged perioperatively compared with basal values, whereas in the D2LR group they showed a gradual increase during surgery but remained normoglycemic. On the other hand, in the D5LR group, the plasma glucose concentrations increased markedly both during and after the operation. Furthermore, 3 of 15 patients showed hyperglycemia of more than 300 mg.dl-1 during anesthesia. There was no evidence of lipid mobilization or impaired secretion of insulin, since plasma NEFA, triglycerides, ketone bodies, and insulin remained within normal concentration ranges throughout the sample period in the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1991

Effect of reticuloendothelial blockade on tissue distribution of 99mTc-labeled synthetic liposomes in Ehrlich solid tumor-bearing mice.

The effect of a reticuloendothelial blockade was examined on the tissue distribution of 99mTc-labeled synthetic liposomes prepared from N,N-didodecyl-N alpha-[6-(trimethylammonio)hexanoyl]-L-alaninamide bromide (N+C5Ala2C12) in Ehrlich solid tumor-bearing mice. While a pre-dose of unlabeled phosphatidyl choline liposomes (natural liposomes) hardly influenced the tissue distribution of N+C5Ala2C12 liposomes, the pretreatment of dextran sulfate depressed the uptake in liver accompanied by increasing that in tumor and other tissues except the stomach. However, the extent of liver depression of N+C5Ala2C12 liposomes by dextran sulfate was lower than that of natural liposomes and the pre-dose of unlabeled natural liposomes had a minor effect on the tissue distribution of N+C5Ala2C12 liposomes compared with that of natural liposomes. In the liver uptake of N+C5Ala2C12 liposomes, it was suggested that Kupffer cell phagocytosis was not the main mechanism.

Animals↗