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Biomedical subjects

T Koh

Publications and source records attributed to T Koh.

At least 127 records · Page 7Linked to original sources
PubMed1985

Endogenous opioids and related peptides: from molecular biology to clinical medicine. The Sir Henry Dale lecture for 1985.

Advances in techniques in molecular biology have facilitated the research into endogenous opioids and related peptides in several ways. The organization and expression of genes and the primary structure of three precursor proteins of opioid peptides have been elucidated. These studies predicted the presence of potentially bioactive peptides, which has been confirmed by later studies. Advances in techniques in protein chemistry have helped to elucidate the distribution and molecular forms of endogenous opioids and related peptides in the body, and the processing of precursor proteins. Studies on the function of these peptides have shown a broad spectrum of actions. Leumorphin, a newly identified peptide, has been shown to exhibit unique biological activities. In spite of extensive studies, the physiological and pathophysiological significance of opioid peptide systems are not yet completely understood. This is mainly due to the paucity of our knowledge about opioid receptors. Further studies on the subtypes of opioid receptors will help to elucidate all aspects of the function of endogenous opioids and related peptides.

Animals↗
PubMed1985

[Capgras syndrome--observations in 2 schizophrenic patients].

Two additional cases of Capgras syndrome were reported. In these schizophrenic patients, the abrupt hatred against family members seemed to contribute largely to the genesis of the syndrome in addition to delusional background. At the same time, the importance of delusional retrospective interpretation in these patients as well as in the previously reported case was discussed.

Capgras Syndrome↗
PubMed1984

Serotonin involvement in the inhibition of luteinizing hormone (LH) release during immobilization in castrated male rats.

The involvement of serotonin in mediating the inhibitory effect of immobilization stress on LH secretion in castrated male rats was examined by employing p-chlorophenylalanine (PCPA, 320 mg/kg, ip), an inhibitor of serotonin synthesis, and 5,6-dihydroxytryptamine (5,6-DHT, 50 micrograms, icv), a drug toxic to the indoleaminergic system. Immobilization stress suppressed pulsatile LH release and decreased mean plasma LH levels. Pretreatment with PCPA or 5,6-DHT apparently eliminated the inhibitory effect of immobilization stress on LH release. These results suggest the possible involvement of a serotoninergic mechanism in mediating the suppression of LH release induced by immobilization stress in castrated male rats.

Animals↗
PubMed1984

Plasma disappearance of ovine corticotrophin-releasing factor in man.

Disappearance of immunoreactive ovine corticotrophin-releasing factor (IR-oCRF) from plasma after a single intravenous injection of ovine corticotrophin-releasing factor (oCRF) was studied in man in the morning and evening. Synthetic oCRF (80 micrograms) was injected intravenously to four normal male volunteers at 0900 h or at 2200 h. Blood samples were drawn before and 2, 5, 10, 15, 30, 45, 60, 90 and 120 min after the oCRF injection. Plasma IR-oCRF was measured by a specific radioimmunoassay for OCRF. Plasma concentrations of IR-oCRF after oCRF injections in the morning and in the evening did not differ significantly (P greater than 0.05). Disappearance of IR-oCRF was modelled with a two-exponent function by using a non-linear least squares computer program. The metabolic clearance rate, the apparent initial volume of distribution, the plasma half-life for the fast component and that for the slow component calculated from all eight tests in the morning and evening were 1.49 +/- 0.05 ml/min X kg, 44.4 +/- 1.7 ml/kg, 6.8 +/- 0.7 min and 46.2 +/- 2.3 min (mean +/- SEM), respectively. This relatively long half-life may be responsible for the prolonged biological effect of oCRF administered intravenously. There were no significant differences between parameters of IR-oCRF disappearance curves in the morning and those in the evening (P greater than 0.05).

Adult↗
PubMed1984

Course and prognosis of endogenous-phasic psychoses in adolescence.

The course and the prognosis of endogenous-phasic psychoses in adolescence were discussed on authentic cases with a long enough period of observation. In atypical psychosis, the length of episodes was longer when productive symptoms were present, while the defect symptoms were quite scarce when affective features dominated the episodes. In contrast to adult cases, myth formation was not recognized, while the tendency to repeat the same clinical picture was not consistent. In affective psychosis, the precipitating factors were significantly frequent in the initial episodes. The length of episodes tended to become longer along with the increase in age, but fairly long-lasting remissions were observed in a few patients.

Adolescent↗
PubMed1984

Plasma adrenocorticotropin and cortisol responses to ovine corticotropin-releasing factor in patients with adrenocortical insufficiency due to hypothalamic and pituitary disorders.

Plasma ACTH and cortisol responses to intravenous injection of 100 micrograms synthetic ovine corticotropin-releasing factor (CRF) were studied in 4 patients with hypothalamic hypopituitarism, 2 patients with Sheehan's syndrome, 2 patients with isolated ACTH deficiency and 10 normal subjects. All 4 patients with hypothalamic hypopituitarism had exaggerated plasma ACTH responses to CRF compared to normal subjects and gradual but definite increases in plasma cortisol from low basal levels. Of 2 patients with Sheehan's syndrome, one had slight ACTH and cortisol increases after CRF injection, whereas the other had no increase in either. In 2 patients with isolated ACTH deficiency, plasma ACTH and cortisol remained undetectable (ACTH less than 10 pg/ml, cortisol less than 0.6 microgram/dl) after CRF injection. These results suggest that the CRF test is a useful tool in evaluating patients with secondary adrenocortical deficiency.

Adolescent↗
PubMed1984

[Clinical investigation of cefotiam in combination with aminoglycoside or (and) penicillin against complicated infections with hematopoietic disorders].

Clinical investigation of combination use of cefotiam (CTM), aminoglycoside, or (and) penicillin against complicated infections with hematopoietic disorders was performed, and the results were as follows. Fifty-one patients were administered CTM in combination with aminoglycoside or (and) penicillin. The clinical response was excellent 19.6%, good 27.4%, fair 21.6%, and poor 31.4% showing efficacy rate of 47.1%. The combined therapy of CTM and aminoglycoside was clinical effective in 70% of 10 patients with complicated sepsis. Therefore, combination use of CTM and aminoglycoside is considered to be the first choice for the treatment of complicated sepsis with hematopoietic disorders. The clinical effectiveness of CTM was not influenced by the number of mature neutrophil at the first phase of CTM treatment, but was influenced at the end phase of CTM treatment. Gram-negative bacilli were dominantly isolated from the patients. Pseudomonas sp. was isolated from 70% of the patients with sepsis. No remarkable side effects were observed in this investigation.

Adolescent↗
PubMed1984

[Transfer of cefmenoxime to burn blister fluids].

Transfer of cefmenoxime (CMX) into the burn blister fluids was studied in 10 burned patients with 2 administrated doses (25, 50 mg/kg). CMX concentrations in serum and burn blister fluid after 1 hour intravenous drip infusion were measured using Proteus mirabilis ATCC 21100 as the test organism grown in the DST agar medium. In the case of CMX 25 mg/kg dose, the peak serum concentration was observed 61.5 micrograms/ml at 1 hour, while the peak burn blister fluid concentration was observed 15.2 micrograms/ml at 2 hours. Pharmacokinetic parameters of serum concentration calculated were 1.02 hours as half-life (beta) and 0.42 L/kg as distribution volume, respectively. In the case of CMX 50 mg/kg dose, the peak serum concentration was observed 122.0 micrograms/ml at 1 hour and the peak burn blister fluid concentration was observed 40.8 micrograms/ml at 2 hours. Pharmacokinetic parameters of serum concentration calculated were 1.27 hours as half-life (beta) and 0.55 L/kg as distribution volume. From this study, the dose dependency between 25 mg/kg dose and 50 mg/kg dose in serum and in burn blister fluid is recognized.

Adolescent↗
PubMed1983

Evidence for noradrenergic involvement in naloxone-induced stimulation of luteinizing hormone release in prepubertal female rats.

The effects of phenoxybenzamine an alpha-adrenergic blocker, propranolol a beta-adrenergic blocker, and diethyldithiocarbamate a noradrenaline synthesis inhibitor, on the LH increase induced by naloxone an opiate antagonist, was investigated in 25 day old female rats. Pretreatment with phenoxybenzamine or diethyldithiocarbamate suppressed the LH increase induced by naloxone, whereas pretreatment with propranolol had no significant effects on the naloxone-induced LH release. These results suggest that naloxone-induced increase in LH release is mediated via a noradrenergic mechanism.

Animals↗
PubMed1983

Plasma adrenocorticotropin and cortisol responses to intravenous injection of corticotropin-releasing factor in the morning and evening.

Plasma ACTH and cortisol responses to corticotropin-releasing factor (CRF) were determined in the morning and evening in seven normal men. Either 100 micrograms synthetic ovine CRF or saline was given intravenously at 0900 h and at 2200 h. Blood samples were collected before and 15, 30, 45, 60, 90, and 120 min after CRF or saline injection. Plasma ACTH concentrations before and after CRF injection in the morning were significantly higher (P less than 0.05) than those in the evening at all times except 45 min after injection. Plasma cortisol concentrations before and at all times after CRF injection in the morning were also significantly higher (P less than 0.05) than those in the evening. However, neither the maximum increments in plasma ACTH and cortisol above the control levels nor increments at each time point following CRF injection in the morning differed significantly from those in the evening. Increments in the area under the ACTH and cortisol concentration curves after CRF injection in the morning also did not differ significantly from those in the evening. These results suggest that the responsiveness of the pituitary to CRF in the morning and in the evening does not differ significantly, although actual values of plasma ACTH and cortisol are higher in the morning.

Adrenocorticotropic Hormone↗
PubMed1983

Inexpensive double-antibody fluoroimmunoassay for aminoglycoside antibiotics, phenytoin, and theophylline in serum.

We describe simple, clinically useful double-antibody fluoroimmunoassays for amikacin, gentamicin, tobramycin, theophylline, and phenytoin. The fluorescent tracers were prepared by conjugation to fluorescein isothiocyanate; the antisera were raised in rabbits. A simple filter fluorometer and disposable culture tubes are used. The tracer, sample, and first and second antibodies are combined and incubated at room temperature for 30 min. A precipitation-acceleration buffer is added, the samples are centrifuged, and the fluorescence of the supernate is measured directly in the assay tube without decantation. Interferences, usually negligible, can be corrected for by use of a sample blank. Results compare favorably in performance with various commercially available RIA and enzyme immunoassays.

Aminoglycosides↗