Expression of dystroglycan and the laminin-alpha 2 chain in the rat peripheral nerve during development

In Schwann cells, the transmembrane glycoprotein beta-dystroglycan comprises the dystroglycan complex, together with the extracellular glycoprotein alpha-dystroglycan, which binds laminin-2 (alpha 2/beta 1/gamma 1), a major component of the Schwann cell basal lamina. To provide clues to the biological functions of the interaction of the dystroglycan complex with laminin-2 in peripheral nerves, we investigated the expression of beta-dystroglycan and the laminin-alpha 2 chain in rat sciatic nerve during development by immunoblot, immunofluorescence, and immunoelectron microscopic studies. The expression of beta-dystroglycan and the laminin-alpha 2 chain in the rat sciatic nerve was low and not confined to the Schwann cell outer membrane from embryonic day 18 to birth, when there was only an immature basal lamina assembly and no compact myelin formation by Schwann cells. However, the expression of these proteins increased markedly and became clearly localized to the Schwann cell outer membrane between birth and postnatal day 7, when both basal lamina assembly and compact myelin formation by Schwann cells progressed rapidly. From postnatal day 7 to adult, there was no remarkable change in the expression of these proteins. Our results support the hypothesis that the dystroglycan complex functions as an adhesion apparatus, binding the Schwann cell outer membrane with the basal lamina, and suggest that the dystroglycan complex plays a role in Schwann cell myelination through its interaction with laminin-2.     

Mandibular bone invasion by gingival carcinoma on dental CT images as an indicator of cervical lymph node metastasis

OBJECTIVES: To evaluate the significance of mandibular bone invasion by gingival carcinoma revealed by reformatted dental CT images as a prognostic indicator of cervical metastasis. METHODS: Thirty-two patients with squamous cell carcinoma of the lower gingiva were examined by dental CT. Cervical metastases and survival rates of these patients were analysed in relation to their clinical characteristics, histologic grading based on gingival biopsy, and mandibular bone invasion using reformatted dental CT imaging diagnoses prior to surgery. The dental CT images were classified into four types: Class I, no bone invasion; Class II, invasion confined to the alveolus; Class III, invasion extending between the alveolus and the mandibular canal; and Class IV, invasion beyond the mandibular canal. RESULTS: Logistic multivariate regression analysis showed that bony invasion identified on dental CT images was a significant prognostic factor in cervical metastases (P=0.028). The 5-year overall survival rates of Classes I, II, III, and IV were 100% (n=9), 76.2% (n=9), 71.4% (n=7), and 28.6% (n=7), respectively. CONCLUSIONS: The evaluation of mandibular bone invasion using dental CT images is useful as a prognostic indicator of cervical metastasis for patients with gingival carcinoma.     

Decreased taurine concentration in skeletal muscles after exercise for various durations

PURPOSE: To examine the changes of taurine concentrations in blood and skeletal muscles after transient exercise. METHODS: Rats were placed on a treadmill set at 25 m.min-1. The animals were divided into four groups: control (no exercise) and exercise groups 1, 2, and 3. The exercise duration for groups 1, 2, and 3 was 30, 60, and 100 +/- 12.5 min (to exhaustion: mean +/- SD), respectively. We examined the plasma concentrations of taurine and lactate, the serum concentrations of sodium and chloride ions, as well as the skeletal muscle taurine content in the soleus (slow-twitch fiber dominant type), gastrocnemius (slow- and fast-twitch fiber mix type), and plantaris and extensor digitorum longus (fast-twitch fiber dominant type) muscles. RESULTS: Although the plasma taurine concentration was not affected by the increased exercise duration, that in skeletal muscles was significantly decreased. The gastrocnemius and plantaris muscles from the exercise group 3 had a significantly lower concentration of taurine than those of the control group. The extensor digitorum longus taurine concentration from the different exercise groups was significantly decreased compared with that from the control group. However, there was no significant difference among the exercise groups. CONCLUSION: Taurine concentration was decreased in all skeletal muscles after exercise, regardless of the duration. Moreover, this decrease was specific to fast-twitch dominant fibers. However, under these conditions, the plasma taurine concentration remained unchanged.     

Role of P-Glycoprotein in Ocular Clearance of Rhodamine 123 in Rabbits

Pharmaceutical Research -     

The Influence of the Product Liability Act, Governmental Regulation, and Medical Economics on Medical Devices and Their Clinical Applications

Abstract: The advancement of medical technology constantly demands the introduction of safer and more efficient medical instruments and devices. Recent litigation and rulings against the manufacturers of breast implants and the subsequent refusal of major plastic companies to supply materials to them are seriously threatening the production and development of other permanent implants such as ventricular assist devices and even disposable catheters. In addition, government overregulation also discourages and hinders production and clinical applications of new instruments. Current trends such as cost effectiveness measures and economic restraints imposed by government agencies and managed care systems are endangering investments from the medical and industrial communities to exploit more expensive and sophisticated instrument technologies. The resultant lack of grant money and pressure from animal rights advocates also suppress experimentation on primates and domestic laboratory animals.     

Differential Sensitivity to the Effects of Psychotropic Drugs: Psychotics vs Normals; Asian vs Western Populations

Abstract: The effects and side-effects of psychotropic drugs are determined by many variables, and the host factor is one of the most important. A lower sensitivity of schizophrenics than normals to the sedative effect of chlorpro-mazine and of manic depressives to imipramine were demonstrated quantitatively by a higher percent time of waking EEG following medication. The mean therapeutic dose of chlorpromazine for the manic state was found to be much lower in Japanese than in Western populations in a controlled study comparing the antimanic efficacy of carbamazepine and chlorpromazine. A lower therapeutic dose in Asian populations has been reported also on other antipsychotic drugs, lithium, and tricyclic antidepressants. The lower therapeutic dose level was discussed from the standpoint of transcultural psy-chopharmacology.     

Effect of 7-Bromo-5-(2-pyridyl)-3H-l, 4-benzodiazepine-2(1H)-one, Bromazepam (Ro 5–3350), a New Minor Tranquilizer, on Psychoneurosis with Special Reference to the Obsessive-Compulsive Symptoms

Clinical application of a minor tranquilizer bromazepam, 7-Bromo-5-(2-pyridyl)-3H-1,4-benzodiazepine-2(lH)-one (Ro 5–3350) was made on 18 cases of obsessive-compulsive neurosis, 10 of anxiety neurosis, 6 hypochondriasis, 4 hysteria and 3 of phobia of bodily odor.

• 1) In 18 cases of obsessive-compulsive neurosis, bromazepam was found markedly effective in 6, effective in 3, fairly effective in 5, ineffective in 2, and aggravated in 2 cases. The effective cases were those with obsessive thinking and manifest anxiety. In other kind of neurosis, bromazepam was markedly effective in 5 and effective in 2 of 10 anxiety neurotic cases, whereas it was almost ineffective in the cases of hypochondriasis, hysteria and phobia of bodily odor.
• 3) The maximum daily dose of bromazepam was 10 to 20 mg in many cases, and 20 to 30 mg in some other cases. The durg is quick-acting to such an extent that it took 2 to 5 days for its action to become manifest in markedly effective cases.
• 4) Various laboratory tests revealed no appreciable abnormality in most cases where bromazepam was employed. Physical side effects such as slight hypotension, dizziness, and sleepiness were observed in a few cases, and mental side effects such as loquaciousness and restlessness in about 20 cases.
• 5) The target symptoms of bromazepam were suggested to be anxiety, tension, and irritation like previously reported other benzodiazepines. The fact that its action of relieving anxiety and tension and of elevating mood was found to be more potent than those of other benzodiazepines and that it was effective on some obsessive-compulsive neurosis that showed little response to other benzodiazepines, suggested that bromazepam is a potent and characteristic new minor tranquilizer of clinical value.