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Biomedical subjects

S Sakai

Publications and source records attributed to S Sakai.

At least 19 recordsLinked to original sources
PubMed1992

[Diagnostic imaging of polysplenia syndrome in the adult].

Polysplenia syndrome is a congenital disorder of situs that is characterized by the presence of multiple spleens and a variable combination of thoracic and visceral anomalies. We present three adult cases of polysplenia syndrome with emphasis on the diagnostic imaging findings. Computed tomography could best determine the exact location and shape of the anomalous organs. The visceral anomalies observed in our patients included multiple spleens, interruption of the inferior vena cava (IVC), azygos or hemiazygos continuation, left-sided IVC, symmetrical liver, anomalous fissure of the liver, anomalous lobe of the liver, median location of the gallbladder, short pancreas, inverted stomach, gallbladder and pancreas, and intestinal malrotation.

Female↗
PubMed1992

The crystal structure and physicochemical properties of L-ascorbic acid 2-glucoside.

The stable L-ascorbic acid glucoside produced by the action of the cyclomaltodextrin glucanotransferase (CGTase, EC 2.4.1.19) from Bacillus stearothermophilus was crystallized from an aqueous solution. Determination of the molecular structure by single crystal X-ray analysis showed the compound to be 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G). The crystals are orthorhombic, space group P2(1)2(1)2(1), with unit-cell dimensions a = 11.929 A, b = 24.351 A, and c = 4.864 A. The D-glucopyranose residue has the 4C1 conformation. These conclusions are in good agreement with those based on the 13C-NMR spectrum. The general physicochemical properties of crystalline AA-2G are reported.

Ascorbic Acid↗
PubMed1992

Antitumor effect of triphenylethylene derivative (TAT-59) against human breast carcinoma xenografts in nude mice.

The antitumor activity of a newly synthesized triphenylethylene derivative [(E)-4-[1-[4-[2-(dimethylamino)ethoxy-phenyl]-2-(4-isopropyl)phenyl-1- butenyl] phenyl monophosphate] (TAT-59) was investigated against human breast carcinoma xenografts in nude mice with reference to the changes of hormone receptors. Five strains (MCF-7, Br-10, R-27, ZR-75-1, and T-61) used for the experiments possessed cytosol estrogen receptor (ER), and their growth was estradiol dependent. Five mg of TAT-59 and tamoxifen citrate (TAM) per kg were administered p.o. daily except Sunday. TAT-59 showed a positive antitumor effect against MCF-7 and R-27, whereas TAM was effective on MCF-7, and their adverse effects detected by mortality rate, body weight loss, and spleen weight loss were similar to each other. The reduction of ER and production of progesterone receptor (PgR) after the treatment with TAT-59 were more potent than after TAM, suggesting that TAT-59 exerts its antitumor effect through binding to ER. These findings suggest that TAT-59 might merit use in clinical trials with breast cancers.

Animals↗
PubMed1992

Phenytoin partially antagonized L-type Ca2+ current in glucagon-secreting tumor cells (ITC-1).

Transmembrane Ca2+ currents were investigated by means of a whole-cell clamp technique in a hamster glucagon-secreting tumor cell line (ITC-1). Two types of Ca2+ current were identified in ITC-1 cells. The low-threshold and transient (T-type) current became detectable above the potential level around -60 mV and decayed rapidly with an inactivation time constant of 95 ms (at -40 mV and 23 degrees C), while the high-threshold and long-lasting (L-type) one was activated by depolarization more positive to -30 mV with non-inactivating kinetics. The voltage dependence and kinetics of these currents were identical to those reported in guinea-pig pancreatic alpha 2 cells. Both currents were augmented by equimolar substitution of Ca2+ with Ba2+ and completely abolished by adding 1 microM La3+. Phenytoin, a well known anti-epileptic drug and a postulated T-type specific Ca2+ current antagonist, surprisingly blocked the L-type current without affecting the T-type current in ITC-1 cells. While phenytoin antagonized the L-type Ba2+ current selectively, 60% of the current remained even in supramaximal concentration range over 500 microM. The residual component of the L-type current was completely abolished by adding nifedipine.

Animals↗
PubMed1992

Radioreceptor assay of serum prolactin using nitrocellulose membrane-immobilized mammary prolactin receptor.

Triton-solubilized rabbit mammary prolactin (PRL) receptor was purified by concanavalin A-agarose chromatography and immobilized on a nitrocellulose membrane. Using the membrane-bound receptor and bovine serum, the serum level of PRL was determined by radioreceptor assay (RRA). The displacement curve, obtained by serial dilutions of the serum, was parallel to that obtained in the range of 0.4 and 20 ng/ml of standard bovine PRL. Serum could be included in concentrations up to 16% of the assay buffer and, thus, the detection limit of serum PRL was about 2.5 ng/ml. PRL in the serum was determined by radioimmunoassay (RIA). The ratio of the RIA and RRA estimates of PRL was 0.99 (r = +0.99, n = 55). The gel-filtration profile of serum PRL was identical to that obtained by RIA. It was concluded that membrane-bound receptor can be used for the determination of serum PRL.

Animals↗
PubMed1992

Effects of hirsutine, an antihypertensive indole alkaloid from Uncaria rhynchophylla, on intracellular calcium in rat thoracic aorta.

The effects of hirsutine, an indole alkaloid from Uncaria rhynchophylla (MIQ.) Jackson, on cytosolic Ca2+ level ([Ca2+]cyt) were studied by using fura-2-Ca2+ fluorescence in smooth muscle of the isolated rat aorta. Noradrenaline and high K+ solution produced a sustained increase in [Ca2+]cyt. Application of hirsutine after the increases in [Ca2+]cyt induced by noradrenaline and high K+ notably decreased [Ca2+]cyt, suggesting that hirsutine inhibits Ca2+ influx mainly through a voltage-dependent Ca2+ channel. Furthermore, the effect of hirsutine on intracellular Ca2+ store was studied by using contractile responses to caffeine under the Ca(2+)-free nutrient condition in the rat aorta. When hirsutine was added at 30 microM before caffeine treatment, the agent slightly but significantly reduced the caffeine-induced contraction. When added during Ca2+ loading, hirsutine definitely augmented the contractile response to caffeine. These results suggest that hirsutine inhibits Ca2+ release from the Ca2+ store and increases Ca2+ uptake into the Ca2+ store, leading to a reduction of intracellular Ca2+ level. It is concluded that hirsutine reduces intracellular Ca2+ level through its effect on the Ca2+ store as well as through its effect on the voltage-dependent Ca2+ channel.

Alkaloids↗
PubMed1992

Biotransformation of tabersonine in cell suspension cultures of Catharanthus roseus.

To investigate the reactions involved in the biosynthesis of vindoline from tabersonine, the bioconversion products formed when the latter compound was fed to cell suspension cultures of Catharanthus roseus were isolated and characterized. Two biotransformation products of tabersonine were isolated and shown to be lochnericine, which is formed by epoxidation of tabersonine at positions 14, 15, and lochnerinine, the 11-methoxylation product of lochnericine. The bioconversion ratio of the main biotransformation product, lochnericine, reached a value of 80.6% within three days.

Alkaloids↗
PubMed1992

Regulatory functions of soluble auxin-binding proteins.

Since the effects of auxin on plant tissues are complex, the mode of action of auxin at the molecular level may not depend on a single mechanism. There may be a mechanism by which the interaction of auxin with receptors localized in the cytoplasmic membranes activates certain enzymes which are necessary to generate the putative second messengers. On the other hand, soluble auxin-binding proteins have been isolated from a variety of plant tissues. Some of these proteins have a high affinity for auxins and the binding is auxin specific, reversible, and saturable, characteristics which suggest that these proteins may be auxin receptors. Although these criteria are often used to distinguish real receptors from nonfunctional binding proteins, it is necessary to clarify the biological function of the binding proteins to classify them as putative receptors. The reported results on the function of soluble auxin-binding proteins demonstrate that, in the transcription system composed of isolated nuclei, auxin interacts with soluble auxin-binding proteins and stimulates the expression of specific genes. Thus, one of the mechanisms of action of auxin may involve a direct interaction with a soluble receptor protein, such that the resultant auxin-receptor complex, possibly together with other protein factors, can subsequently recognize the promoter region of specific gene(s) and interact with RNA polymerase II to cause a transcription of the gene(s).

Indoleacetic Acids↗
PubMed1992

Spontaneous pain in patients with maxillary sinus carcinoma in relation to T-classification and direction of tumour spread.

Spontaneous pain was one of many complaints on initial examination of 845 patients with maxillary sinus carcinoma. The pain was analysed; cheek, teeth, head and eye pain were compared with the T-classification and the anterior-posterior direction of invasion. The incidence of the cheek, teeth, head and eye pain was 48, 39, 29 and 23 per cent respectively. The incidence of both the cheek and teeth pain was increased according to the advancement of T-classification and invasion towards the posterior. Head and eye pain was often referred. In the localized posterior group which tend to be diagnosed late, spontaneous pain occurred in 15 to 48 per cent of the patients. Maxillary sinus carcinoma should always be a differential diagnosis in patients with unclear cheek, teeth, head and eye pain. A careful investigation should be performed in order to diagnose malignant diseases as early as possible.

Cheek↗
PubMed1992

Preliminary experience using an ultrasonic aspirator for laparoscopic cholecystectomy.

An ultrasonic aspirator (Olympus) specially designed for laparoscopic surgery, which also includes cautery and suction-irrigation systems, was evaluated in 40 patients undergoing laparoscopic cholecystectomy. The generating power of each system is controlled by hand or foot switches, and most operating procedures could easily be performed through a 10 mm trocar inserted through the abdominal wall. The ultrasonic aspirator successfully fragmented and aspirated soft tissue, allowing a precise differentiation between the cystic duct and artery, small vessels, lymphatics and fibrous tissue. Removal of the gallbladder could be performed successfully using the cautery and ultrasonic aspirator, whereby parts of cauterization or division could easily be identified. Identification of the cystic duct and artery, course of the cystic duct and Hartmann's pouch in the same field of vision was possible which is important for avoiding major complications such as injury of the common bile duct. No complications were seen during or after surgery in any of the patients.

Cholecystectomy, Laparoscopic↗
PubMed1992

Small caliber catheter drainage for spontaneous pneumothorax.

Excellent results have been reported after small caliber catheters were used for iatrogenic pneumothoraces. However, the value of using such catheters for spontaneous pneumothoraces is not clear. The purpose of this study, therefore, is to examine the efficacy of small caliber catheters in managing spontaneous pneumothoraces. Seventy six episodes of spontaneous pneumothorax were treated using a small caliber catheter (No. 5.5 or 7.0 French) connected to a Heimlich valve. All catheters were inserted by physicians. The treatment was considered successful when there was no air leakage and little or no residual pneumothorax. Before the lungs were fully expanded, four patients had died and one had refused to comply with further treatment. The remaining 71 episodes of pneumothoraces were evaluated for efficacy. The treatment was successful in 60 patients (84.5%) and ineffective in the remaining 11. The conventional large caliber tube was inserted in 10 of the 11 failures, but they were successful in only six. No major complications resulting from catheter insertion occurred, and no catheters became occluded. The catheter was easy to insert, and the scar that remained after removal of the catheter was very small. Not only are small caliber catheters effective for managing spontaneous pneumothoraces, they are the initial treatment of choice.

Catheterization↗
PubMed1992

Adipofascial (anterior rectus sheath) flaps for breast reconstruction.

A flat breast after a subcutaneous mastectomy for removal of a foreign body tumor or a benign tumor is not acceptable for many patients. If patients do not wish to use a silicone bag implant for reconstruction, it is necessary to use autologous tissue for the reconstruction of the breast mound. The use of a latissimus dorsi myocutaneous flap or a rectus abdominis myocutaneous flap for breast reconstruction in most patients who underwent subcutaneous mastectomy is too aggressive. Free fat grafts are also generally not effective for such patients because of the absorption of the grafted fat. We developed a procedure involving a cranial-based adipofascial (anterior rectus sheath) flap from immediately below the inframammary area for breast reconstruction. The skin incision is made at the inframammary line. After extirpation of the foreign body, the inframammary skin area is undermined. A tongue-shaped flap of the fat and the anterior sheath of the rectus abdominis muscle, approximately 7 cm in length, is pulled up, gathered, and inserted to reconstruct the breast mound. We used this technique in 7 patients, and the results were satisfactory.

Female↗
PubMed1992

[Epidemiological and bacteriological study on gonococcal infections].

Epidemiological and bacteriological studies on Neisseria gonorrhoeae isolated in Sapporo, Japan, in 1980 and 1991 performed and the following results were obtained. 1. The range of age in the patients infected with Neisseria gonorrhoeae tended to be younger than those in the whole country. 2. Male patients in the early 20s or younger with gonococcal urethritis were often infected by bon-professional females but those in their late 20s or older were often infected from professional females, for example prostitutes and hostesses. 3. The rate of professional females who were positive to gonococci reached 17.4% and young females in their teens with cervicitis had the highest morbidity rate of gonococci than those in the older females. 4. The latent period in gonococcal infections tended to become longer gradually. 5. The isolation rate of penicillinase producing Neisseria gonorrhoeae (PPNG) showed a peak of 23.9% (61/255) in 1985, but gradually declined thereafter and it was 3.7% (1/27) in 1991. 6. An investigation on auxotype showed a decline of proto and Pro-strains and an increase of AHU-strains in non-PPNG. And most of the PPNG belonged to proto or Pro-strains. 7. With the relationship between auxotype and sensitivity to AMPC, AHU-strains were more sensitive than proto or Pro-strains.

Adolescent↗
PubMed1992

Cystic radiolucencies of carpal bones, distal radius and ulna as a marker for dialysis-associated amyloid osteoarthropathy.

Patients on long-term hemodialysis (HD) are known to develop amyloid osteoarthropathy, evidenced as cystic radiolucencies on X-rays of the affected joints. To study the relationship between cystic radiolucencies and amyloid osteoarthropathy in 394 patients, we classified the severity of the cystic radiolucencies seen in the wrist joint on a 4-point scale and evaluated the association between lesion severity (grade) and several parameters. Biopsy was performed in 8 patients with 11 bone cysts of the wrist joint who had been operated for carpal tunnel syndrome. HD for 10 years or longer, age 50 or older and the presence of carpal tunnel syndrome were associated with severe cyst rating. There was no association between lesion grade and serum level of PTH-C, aluminum or beta 2-microglobulin (B2M). Ten of the 11 biopsied bone cysts in 8 patients with carpal tunnel syndrome demonstrated amyloid deposits which reacted with B2M. We conclude that a cystic radiolucency observed in the wrist joint of a patient undergoing HD indicates the deposition of amyloid. The cyst grade provides a useful marker for the severity of amyloid osteoarthropathy in HD patients.

Adult↗
PubMed1992

Brain and cerebrospinal fluid distributions of metoprolol in rats.

The distribution of metoprolol tartrate (MPL) into the brain and cerebrospinal fluid (CSF) from plasma was determined at 2 different steady-state plasma concentrations (2 and 20 nmol/ml) and following intravenous bolus administration (100 nmol/kg) in rats. Under steady-state condition, no difference in the brain and CSF distributions of MPL was observed between 2 different plasma MPL concentrations, and the value of brain- or CSF-to-plasma partition coefficients were 5.7 and 1.5, respectively. Following intravenous administration, MPL distributed into CSF very rapidly and its initial uptake phase was not detected. On the other hand, MPL distribution into the brain was relatively slow with the uptake phase. Thus, the brain uptake of MPL from the plasma was pharmacokinetically analyzed using a modified 2-compartment model and deconvolution method, whereas the CSF distribution of MPL was not adequate for kinetic analysis because of the lack of uptake phase. The analysis of brain uptake of MPL by both compartment model and deconvolution gave the same results and the calculated brain Kp value of MPL was almost comparable with that of observed Kp value under steady-state plasma concentration. The distribution of MPL into CSF was considered mainly depending on the pH difference between the plasma and CSF, and the mutual transfer of MPL between CSF and the brain tissue was considered to be negligible from an in vitro study.

Animals↗
PubMed1992

Application of microdialysis for study of caffeine distribution into brain and cerebrospinal fluid in rats.

The usefulness of microdialysis was examined for the chronological determination of caffeine concentration in the brain and cerebrospinal fluids (CSF) following intravenous administration of caffeine in rats. The recovery percent of caffeine by microdialysis, the concentration ratio of caffeine in the dialysate against that in the brain tissue or CSF was determined. The recovery percent was proved to be constant at 5 different steady-state plasma concentrations of caffeine (0.1-280 nmol/ml) and in different collecting periods of dialysate ranging from 30 s to 10 min. The mean recovery percent in the brain and CSF were 10.9 and 13.1%, respectively. Thus, microdialysis was proved useful for determination of drug concentration in the tissue and biological fluids with time resolution of more than 30 s. The microdialysis method was then applied for the chronological determination of caffeine concentration in the brain and CSF following intravenous bolus administration. The estimated caffeine concentration in the brain and CSF was the same as those obtained by direct determination in isolated brain and CSF, respectively. Transfer of caffeine from plasma to brain and CSF were further pharmacokinetically analyzed using a modified 2-compartment model. In this kinetic model, the transfer of caffeine between the CSF and brain was neglected, since the mutual transfer of caffeine was not detected in in vivo experiments. Calculated curves were well fitted on observed caffeine concentrations in the plasma, brain and CSF.

Animals↗