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Biomedical subjects

M Chin

Publications and source records attributed to M Chin.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Treatment of intractable postherpetic neuralgia and blepharospasm: intraneural injection of adriamycin].

Adriamycin, an anthracycline antineoplastic agent, can swiftly be transported to the sensory or somatic motor neurons by way of axoplasmic transport when injected into the subepineurium of the trigeminal nerve or sciatic nerve in experimental animals, and is consequently able to induce degeneration of the neurons without any systemic side effects. Intraneural injection of this agent was carried out for the treatment of a total of 22 patients presenting with intractable neural dysfunction (12 with neuralgia, including 7 with post-herpetic neuralgia and 10 with facial dystonia). The nerve which innervated the affected site was exposed under local anesthesia and approximately 10-60 microliters of 1-20% adriamycin was injected into the subepineurium. Results of the treatment after average follow-up periods of 21.5 months were as follows: Out of 12 patients with neuralgia, good results were obtained in 2 cases (16.7%), fair results in 6 cases (50.0%) (overall effective rate 67.7%). There were no changes in symptoms in 4 cases (33.3%). Out of 10 patients with facial dystonia, good results were obtained in 2 cases (20.0%), fair in 2 cases (20.0%) (overall effective rate 40.0%), and no changes in symptoms in 6 cases (60.0%). No major complications were encountered during these procedures and, once symptoms had disappeared after the treatment, no recurrence of symptoms was experienced. This method clearly differs from other various kinds of simple peripheral neurotomy, since transection of the peripheral nerve does not cause any, destructive changes in the sensory ganglion or motor nucleus and, hence, symptoms may recur.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Trigeminal neuralgia: association with tentorial meningioma and persistent primitive trigeminal artery.

A rare case of trigeminal neuralgia caused by tentorial meningioma associated with a persistent primitive trigeminal artery (PTA) is reported. This case involved a 59-year-old female patient with a more than 6 month history of left trigeminal neuralgia. A left cerebello-pontine angle (CP angle) meningioma was found associated with a right PTA connecting the proximal portion of the cavernous internal carotid artery with the basilar artery, supplying the bilateral superior cerebellar arteries. The tumor was totally removed via the suboccipital approach, which relieved the pain completely. Since the combination of a CP angle meningioma and a PTA is quite rare in patients with trigeminal neuralgia, we have presented this case here.

Basilar Artery↗
PubMed1994

Unusual presentation of brain metastasis from hepatocellular carcinoma--two case reports.

Two unusual cases of brain metastasis from hepatocellular carcinoma (HCC) are described. A 15-year-old boy presented with intracerebral hemorrhage from brain metastasis from HCC, and died of rebleeding 1 month after surgery. Cerebral metastatic HCC in a child is quite rare, and has not previously been reported. A 65-year-old male with a 2-year history of treatment for HCC presented with a brain metastasis from HCC without intracerebral hematoma manifesting as gradual onset of headache. Brain metastases from HCC presenting without intracerebral hemorrhage are rare.

Adolescent↗
PubMed1994

[Diploic epidermoid on the petrous bone: a case report].

An unusual case of a congenital petrous bone epidermoid which resulted in a sudden deafness is reported. The patient was a 25-year-old man who suddenly developed a right deafness and tinnitus. Neurological examination on admission revealed slight hearing disturbance in the high sound area. Plain craniogram showed a destructive bone lesion in the middle portion of the petrous bone on the right side. Bone-window CT scan disclosed a bony destructive mass in the petrous bone, and enlargement of the internal auditory canal. The mass lesion was almost isodense on plain CT scan and was not enhanced by contrast media. T1 weighted imaging of MRI demonstrated an isointense mass in the petrous bone, and T2 weighted imaging demonstrated hyperintensity. Gd-DTPA MRI revealed no enhancement. Angiogram did not reveal abnormal findings. Right lateral suboccipital craniectomy was performed to remove the posterior wall of the internal auditory canal. The tumor existed extradurally originating from the dipole of petrous bone. The tumor appeared pearly and fragile. The pathological examination of the specimen was diagnosed as epidermoid. The postoperative course was uneventful except for right hearing loss on the 4th postoperative day. Epidermoid arising in the middle portion of the petrous bone is quite rare, so this case was hereby reported with some references.

Adult↗
PubMed1993

Effects of canine myocardial infarction on sympathetic efferent neuronal function: scintigraphic and electrophysiologic correlates.

We studied the effects of nondecentralized left stellate ganglion stimulation on regional epicardial monophasic action potential duration at 50% (APD50) and 90% (APD90) repolarization from 104 sites in 10 surviving dogs with a chronic myocardial infarction model. These effects were correlated with thallium-201 and iodine-123 metiodobenzylguanidine (MIBG) imaging to identify areas of viable but denervated myocardium. Mean infarct size was 5.2% +/- 0.8% total heart weight, and the planimetered areas of denervation were always larger (18% +/- 4% total heart area). During constant ventricular pacing, stellate stimulation tended to shorten the APD90 only in normally innervated areas (364 +/- 5 to 358 +/- 5 msec) and to increase in denervated areas (358 +/- 5 to 362 +/- 5 msec), (p value not significant (NS) for prestellate and poststellate stimulation; p < 0.05 for difference between denervated vs innervated). The APD50 significantly shortened in innervated areas from 287 +/- 5 to 270 +/- 3 msec (p < 0.05) compared with denervated areas (283 +/- 4 to 274 +/- 5 msec, p = NS). We conclude that MIBG imaging demonstration of denervation identifies areas with impaired shortening of the epicardial APD50 in response to stellate stimulation and that nontransmural myocardial infarction produces areas of denervation larger than areas of necrosis.

Action Potentials↗
PubMed1993

[A case of macrocystic cervical neurinoma diagnosed by MRI with Gd-DTPA].

The authors report a rare case of a large cystic cervical neurinoma. A 45-year-old female was admitted to our clinic because of motor weakness of the right upper extremity, numbness of the right fingers and right posterior cervical pain. Metrizamide CT myelography demonstrated the outline of a low density mass. MRI showed a mass revealing low signal intensity on T1-weighted image, high signal intensity on T2-weighted image and marginal enhancement on contrast image with Gd-DTPA. The mass which was diagnosed as cystic tumor, was located in the intradural extramedullary space between C4 to C5 segments. After C4 through C5 laminectomy, the tumor was found to originate from the C5 anterior motor root. The tumor consisted mostly of a cystic part with a very thin solid compartment beneath the capsule. Postoperative course of the patient was uneventful. Although spinal neurinoma is one of the most common spinal tumors, an almost completely degenerated large cystic spinal neurinoma is extremely rare. MRI with Gd-DTPA was useful for the diagnosis of the cystic neurinoma by clearly enhancing the margin of the tumor.

Cysts↗
PubMed1992

DNA-directed alkylating agents. 5. Acridinecarboxamide derivatives of (1,2-diaminoethane)dichloroplatinum(II).

A series of acridine-2- and -4-carboxamide-linked analogues of PtenCl2 has been prepared and evaluated for biological activity against several tumor cell lines in vitro and in vivo. The platinum complexes were generally more cytotoxic than the corresponding ligands against wild-type P388 leukemia cells in vitro, with acridine-4-carboxamide complexes being the more effective. In contrast to cisplatin and PtenCl2, the complexes were equally active in vitro against both wild-type and cisplatin-resistant P388 lines. The 4-carboxamide complexes showed high levels of in vivo activity (ILS greater than 100%) against wild-type P388 using a single-dose protocol, and one compound was also significantly active in vivo in a cisplatin-resistant line, against which cisplatin and PtenCl2 are inactive.

Acridines↗
PubMed1992

Anti-platelet action of isoliquiritigenin, an aldose reductase inhibitor in licorice.

The mechanism was studied by which isoliquiritigenin, a new aldose reductase inhibitor purified from licorice (Glycyrrhizae radix), inhibits platelet aggregation. This new agent significantly inhibited the phosphorylation of 40,000- and 20,000-dalton proteins, and inhibited the formation of 12 (S)-hydroxy-5,8,10-heptadecatrienoic acid, 12-hydroxyeicosatetraenoic acid and thromboxane B2. The inhibitory effect of isoliquiritigenin on platelet aggregation in vitro was comparable to that of aspirin. Our findings may indicate that isoliquiritigenin elicits an anti-platelet action by inhibiting not only cyclooxygenase but also lipoxygenase or peroxidase activity in platelets. Isoliquiritigenin also showed an anti-platelet action in vivo. Isoliquiritigenin appears to be the only aldose reductase inhibitor with a significant anti-platelet action. Since the hyperaggregability of platelets has been implicated in the pathogenesis of diabetic complications, isoliquiritigenin may offer a unique benefit as an aldose reductase inhibitor.

Aldehyde Reductase↗
PubMed1992

Effects of sympathetic stimulation on use dependence of lidocaine, mexiletine, and quinidine in an intact canine model.

The use- or rate-dependent effects of a continuous infusion of lidocaine (n = 6, serum level 3.1 +/- 0.34 micrograms/mL), mexiletine (n = 8, serum level 7.08 +/- 0.90 micrograms/mL), and quinidine (n = 6, serum level 6.8 +/- 1.22 micrograms/mL) were studied in an open chest canine preparation. A use-dependent effect on conduction was assessed by measuring the change in the His to surface ventricular activation (HV) time at differing atrial paced rates during drug infusion. Global sympathetic activation was achieved by nondecentralized left stellate ganglion stimulation (4-10 Hz, 6-12 V, 2 ms) and use dependence at the same cycle lengths was compared. Repolarization times were measured from epicardial monophasic action potentials recorded from the anterior left ventricle throughout the study. There was no significant change in the HV time during control studies with or without left stellate stimulation. Use-dependent slowing of conduction was seen in all studies during drug infusion. This was evident at cycle lengths of 300-190 ms for quinidine and at cycle lengths less than 250 ms for lidocaine and mexiletine. Stellate stimulation attenuated use dependence in all studies. This effect was significant from cycle lengths of 300-190 ms for lidocaine and quinidine and at cycle lengths shorter than 230 ms for mexiletine (p less than 0.05). Stellate stimulation significantly reduced use-dependent prolongation of the HV interval by an average of 60%. During stellate stimulation there was a nonsignificant trend towards cycle length independent shortening of action potential duration both at baseline and in the presence of drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1991

Ablation of the atrioventricular junction with radiofrequency energy using a new electrode catheter.

Percutaneous catheter ablation using radiofrequency energy can be used to interrupt atrioventricular (AV) conduction in patients with supraventricular tachycardia refractory to drugs. Results of radiofrequency ablation of the AV junction using a custom-designed catheter with a large, 3-mm-long distal electrode, 2-mm interelectrode spacing, and a shaft with increased torsional rigidity were compared with those using a standard quadripolar electrode catheter (Bard EP). An electrocoagulator (Microvasive Bicap 4005) supplied unmodulated radiofrequency current at 550 kHz, which was applied between the distal electrode of the ablation catheter and a large skin electrode. With use of the modified catheter, 12 of 13 patients (92%) had persistent complete AV block induced with 7 +/- 5 applications of 18 +/- 6 W of radiofrequency power. In contrast, complete AV block was produced in only 9 of 18 (50%) historical control patients treated with the standard catheter, despite a similar number of applications (7 +/- 5) and power output (16 +/- 4 W). A rise in impedance, due to desiccation of tissue and coagulum formation, occurred earlier (28 +/- 18 vs 52 +/- 24 seconds, p less than 0.001) and more frequently (54 vs 40% of applications, p = 0.047) in patients treated with the standard catheter than in patients treated with the modified catheter. The use of a catheter designed to increase the surface area of electrode-tissue contact allows more radiofrequency energy to be delivered before a rise in impedance occurs and appears to increase the effectiveness of radiofrequency ablation of the AV junction.

Atrioventricular Node↗
PubMed1991

Nine phenethyl alcohol glycosides from Stachys sieboldii.

Three new phenethyl alcohol glycosides together with six known compounds have been isolated from the leaves of Stachys sieboldii. On the basis of chemical and spectral analyses, the structures of three new compounds named stachysosides A, B and C have been established as 2-(3,4-dihydroxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E-caffeoyl-beta-D-glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E-feruloyl-beta-D-glucopyranoside and 2-(3-hydroxy-4-methoxyphenyl)ethyl O-alpha-L-arabinopyranosyl-(1----2)-alpha-L-rhamnopyranosyl- (1----3)-4-O-E- feruloyl-beta-D-glucopyranoside, respectively.

Carbohydrate Sequence↗
PubMed1991

Blood viscosity measurement for screening of affecting blood circulation.

An in vitro screening test for drugs that decrease blood viscosity was carried out on many pharmacologically active compounds such as Ca-antagonists, alpha-antagonists, beta-antagonists, alpha, beta-antagonists, alpha-agonists, beta-agonists, alpha, beta-agonists, autacoids and others. The results revealed that various types of microcirculatory-improving drugs, vasodilators, and antagonists decreased blood viscosity, while the agonists and autacoids had no significant effect. These findings suggest that this assay is useful for screening compounds related to hemorheology.

Animals↗
PubMed1991

Electrocution injuries. A case report.

A case study of a high-voltage injury was presented. The short period that the patient was in contact with the electrical source prevented further systemic injury and may have saved her life. The patient's present neuritis is indicative of long-term sequelae of electrocution injury, in which ischemic necrosis of the surrounding nerves can occur near or at the site of the exit wound.

Adult↗
PubMed1990

Isoliquiritigenin: a new aldose reductase inhibitor from glycyrrhizae radix.

Traditionally in Japan, some kampo medicines (traditional oriental herbal prescriptions) have long been used for the treatment of diabetic neuropathy. We have found that some aldose reductase inhibitors are included among these drugs. We further investigated the components of glycyrrhizae radix, a constituent of some kampo medicines, and isolated six compounds (GUs 9-17). Among these, GU-17, identified as isoliquiritigenin, had the most potent aldose reductase inhibiting activity. Isoliquiritigenin inhibited rat lens aldose reductase with an IC50 of 3.2 x 10(-7) M, using DL-glyceraldehyde as a substrate. It inhibited sorbitol accumulation in human red blood cells in vitro, with an IC50 of 2.0 x 10(-6) M. Isoliquiritigenin, when administered via an intragastric tube to diabetic rats, suppressed sorbitol accumulation in the red blood cells, the sciatic nerve, and the lens as effectively as ONO-2235. These results suggest that isoliquiritigenin may be effective in preventing diabetic complications.

Aldehyde Reductase↗
PubMed1990

Anti-platelet action of GU-7, a 3-arylcoumarin derivative, purified from glycyrrhizae radix.

We have purified GU-7, a 3-arylcoumarin derivative, from glycyrrhizae radix, which is a crude drug of kampo herbal medicines. This was identified to be a new chemical compound and was found to have an anti-platelet action. GU-7 inhibited platelet aggregation, phosphorylation of 40K and 20K dalton proteins, inositol 1,4,5-trisphosphate production, intraplatelet calcium increase and phosphodiesterase activity in vitro. The data indicate that GU-7 inhibits platelet aggregation by increasing intraplatelet cAMP concentration. We have already reported the existence of aldose reductase inhibitors in some kampo medicines. In addition to the aldose reductase inhibiting action, anti-platelet action may also explain the mechanism by which kampo medicines are effective to diabetic neuropathy.

Coumarins↗