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Biomedical subjects

T Higuchi

Publications and source records attributed to T Higuchi.

At least 667 records · Page 37Linked to original sources
PubMed1979

Twenty-four-hour secretory patterns of growth hormone, prolactin, and cortisol in narcolepsy.

Twenth-four-hour patterns of plasma GH, PRL, and cortisol concentrations concomitant with sleep stages were studied in four male patients with typical narcolepsy, aged 30--34 yr, and four normal subjects. All medications were withdrawn 2 weeks before the study. Blood was drawn every 20 min during a 24-h fasting period, except for the first sleep cycle of nocturnal sleep when samples were drawn at 5-min intevals. In all of the narcoleptics, a plasma GH peak associated with slow wave sleep at the nocturnal sleep onset was absent (n = 2) or markedly decreased (n = 2). The normal rise of PRL during sleep was present only in a narcoleptic, whereas a significant fall in plasma PRL concentrations occurred immediately after the sleep-onset rapid eye movement period and lasted 1--1.5 h in the remaining three patients. A sleep-onset rapid eye movement period occurred in all of the patients, and this abnormal phenomenon characteristic of narcolepsy was considered to be related to the suppression of GH release at the sleep onset and to the decrease of plasma PRL levels during the early part of sleep. In contrast, the normal circadian periodicity of cortisol secretion was evident in all of the narcoleptics.

Adult↗
PubMed1979

Effects of active and passive immunization with LH-RH on gonadotrophin secretion and reproductive function in female rats.

In order to get information about the physiological role played by LH-RH in the regulation of tonic and phasic secretion of gonadotrophins, and about the existence of FSH-RH distinct from LH-RH, we attempted to neutralize endogenous LH-RH by passive and active immunization with LH-RH in female rats. Anti-LH-RH serum prevented pre-ovulatory gonadotrophin surges at proestrus and ovulation, and it suppressed gonadotrophin increase induced by oestradiol benzoate or progesterone in ovariectomized rats. Elevated serum gonadotrophin concentrations in long-term ovariectomized rats were lowered by anti-LH-RH serum injection. The decrease in FSH levels was less than that in LH levels. Serum FSH rose without significant changes in serum LH level for 6 h after ovariectomy on pro-oestrus or dioestrus. The post-ovariectomy rise of FSH was not suppressed by the anti-LH-RH serum which was enought to inhibit serum LH to undetectable levels. Active immunization with LH-RH resulted in decreasing LH levels but failed to alter FSH levels in both serum and pituitary. Seven out of 10 rats immunized with LH-RH became constantly di-oestrous. The weights of anterior pituitary, ovary and uterus of the LH-RH immunized rats were significantly smaller than those of BSA immunized controls. Ovaries of LH-RH immunized rats contained few fresh corpora lutea. These results indicate that LH-RH plays a significant role in the control of both plastic and tonic secretion of LH and FSH. The existence of FSH-RH distinct from LH-RH or mechanism which specially controls the basal FSH secretion is indicated.

Animals↗
PubMed1978

Controlled delivery of theophylline: chemistry of 7-acyl- and 7,7'-acylditheophylline derivates.

7-Acyl- and 7,7'-acylditheophylline derivatives were prepared from the reaction of theophylline with acid chlorides. In addition, a novel synthesis of these compounds was developed, which proceeds through an acylonium ion generated under mild conditions. The physical properties and stability of the derivative of choice, 7,7'-succinylditheophylline, depend on the synthetic procedure employed. This compound is a useful controlled-release prodrug of theophylline.

Animals↗
PubMed1978

Enhancement of bioavailability of a hydrophobic amine antimalarial by formulation with oleic acid in a soft gelatin capsule.

The relative availability of the orally administered hydrophobic antimalarial alpha-(dibutylaminomethyl)-6,8-dichloro-2-(3',4'-dichlorophenyl)-4-quinolinemethanol (I) from two dosage forms was determined in beagle dogs. Compound I was soluble in oleic acid to the extent of 23.5% (w/w), and oleic acid was suitable for encapsulation in soft gelatin capsules. The availability of I formulated as its hydrochloride salt in a standard hard gelatin capsule formulation was significantly lower than that of I formulated in a soft gelatin capsule with oleic acid as the solvent. A 20% solution of I in oleic acid (soft gelatin capsules) maintained at 23 degrees provided 4% of the oleic acid ester of I iwithin 1 month. Further reaction, however, was not seen over 2 years.

Animals↗
PubMed1978

Photocontact dermatitis from P-aminobenzoic acid.

A 6-year-old girl with xeroderma pigmentosum was contact and photocontact sensitized to PABA which had been used as a sunscreening agent. The activating wavelengths for photocontact dermatitis were in long-wave ultraviolet light. The experimental photocontact sensitization was not induced in guinea pigs. Although PABA is the most effective and harmless sunscreening agent for normal skin, it could induce photocontact sensitivity especially in diseased or damaged skin.

4-Aminobenzoic Acid↗
PubMed1978

Design of chemical structure for optimal dermal delivery.

The process of dermal absorption can be most conveniently divided into four independent steps, each of which is subject to its own structure-deliverability relationship. These are: (1) the process of release of the active agent molecules from the neat state to the dermal; (2) the process of permeation through the barrier layer; (3) the process of release of the drug from the epidermal barrier phase to the immediate subbarrier layer, (4) the micropharmacokinetics of the drug and its metabolite in the dermal compartment. The rate-controlling process can, in most instances, be identified with one of the first three processes. These in turn are largely subject to the physical chemical, thermodynamic characteristics of the transported species. Although the first process has been essentially ignored by earlier workers, it is in most instances of major concern in designing percutaneously available drug species.

Chemistry, Pharmaceutical↗
PubMed1978

Introduction of a method of valvuloplastic esophagogastrotomy in proximal gastrectomy.

A technique of valvuloplastic esophagogastrostomy is proximal gastrectomy to control postoperative reflux esophagitis is reported. After proximal resection of the stomach, the medial stump is closed in two layers. The mucosal layers of the lateral stump are sewn but leaving the seromuscular layers open. The esophagus is anastomosed to the mucosal stoma at the middle of the gastric stump. The distal esophagus is wrapped by the lateral stump like Nissen's fundoplication to create the artificial fundus. Intragastric esophageal wall facing the fundus acts as a long one-way flap valve to prevent reflux. Ten dogs were prepared with this method and were compared with end-to-end and end-to-side anastomosis prepared in five dogs each. Cinefluoroscopy and esophageal pH demonstrated various degress of reflux in all the dogs with end-to-end and end-to-side anastomosis, and mild reflux in one out of the ten dogs with valvular anastomosis. A sharp rise in pH at the anastomotic site was consistent in the remaining nine valvuloplastic dogs. High pressure zone, 9.9 mmHg on an average at the site of anastomosis was present in valvuloplastic dogs, while the pressure was 0 mmHg in end-to-end and 5.2 mmHg in end-to-side anastomosis dogs. Clinical application of this procedure in ten patients obtained satisfactory results. The technique offers a reliable method of valvuloplastic anastomosis in esophagogastrostomy.

Animals↗