In vitro dissolution tests corresponding to the in vivo dissolution of clarithromycin tablets in the stomach and intestine

The correlation between in vivo and in vitro dissolution of clarithromycin (CAM) tablets was examined. In vivo dissolution rate constants in the stomach and the intestine were obtained from analysis of the urinary excretion data of CAM following oral administration to humans in the fasting or postprandial state using a pharmacokinetic model including gastrointestinal transit. In the present study, the flow-through cell method with moderate agitation was used, as the in vitro dissolution test related to the in vivo dissolution rate constants. Both the effects of pH of the dissolution medium and the volumetric solvent flow rate on the dissolution rate in the flow-through cell method were examined. The pH of the dissolution medium and the flow rate were related to the in vitro dissolution rate. Therefore, the conditions of the flow-through cell method in correlation with the in vivo dissolution rates in the stomach and intestine were determined by controlling the flow rate at pH 3.0 and 6.8 dissolution medium. The urinary excretion of CAM, simulated by substituting the in vitro dissolution rate constants into the equation, were consistent with the in vivo data. The in vitro tests corresponding to the in vivo dissolution in the stomach and intestine following a single oral administration in the fasting or postprandial state for a CAM tablet were established.

[Regional cerebral glucose metabolism associated with ataxic gait--an FDG-PET activation study in patients with olivopontocerebellar atrophy]

We studied changes in regional cerebral glucose metabolism during bipedal gait in 7 patients with olivopontocerebellar atrophy (OPCA) and 7 control subjects without neurological disease. All OPCA patients in this study were able to walk on the treadmill without a support or handrails. We used 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) and positron emission tomography (PET) to evaluate glucose metabolism under two different conditions; 30 minutes' treadmill walking, and supine resting. The two sets of PET images were three-dimensionally registered to the magnetic resonance image (MRI) in each subject. Then, the PET images were normalized by the global value. Regions of interest (ROIs) were drawn on the cerebellar vermis, cerebellar hemispheres, pons, and thalamus, and FDG uptake was obtained to calculate the activation ratio (= [FDG uptake under walking]/[FDG uptake under resting]) for each region. We used unpaired t-test for statistical analysis to compare the OPCA patients and the normal control subjects. Normalized resting FDG uptake had no significant difference between control subjects and OPCA patients in any region. Activation ratio of OPCA patients was significantly decreased in the cerebellar vermis compared with the control subjects. In the control subjects, FDG uptake had little difference between resting and walking in the cerebellar hemisphere, pons and thalamus. On the other hand, the FDG uptake of OPCA patients was moderately increased by walking in these regions. In the cerebellar vermis, in spite of no significant difference between the normals and the patients during resting, the activation ratio in OPCA patients was significantly decreased. We speculate that the reduction of activation ratio in the cerebellar vermis reflects the dysfunction caused by degeneration. The result suggests that the PET activation study can demonstrate cerebellar dysfunction in the early phase of OPCA, in which other neuro-imaging methods cannot detect the tissue atrophy, hypometabolism or hypoperfusion in the resting state. In the cerebellar hemisphere, pons and thalamus, the activation ratio was nearly equal to one in control subjects, while it was larger in OPCA patients. We speculate that the instability during the ataxic gait increases the inputs from the vestibular, somatosensory and visual systems to these regions and outputs from these regions to the other neural systems. In conclusion, PET activation study is a useful and noninvasive technique for investigating the brain function associated with human gait.

Insulin secretion levels necessary for efficacy of an alpha-glucosidase inhibitor on glucose metabolism in patients with non-insulin-dependent diabetes mellitus

Twenty patients with non-insulin-dependent diabetes mellitus whose glucose metabolism was unsatisfactory, even though they were receiving appropriate dietary therapy, were treated with an alpha-glucosidase inhibitor (0.6 mg/day) for 12 weeks. The connecting peptide immunoreactivity value (selected as the evaluation criterion of post-prandial endogenous insulin secretion) was compared in patients with and without improved glycosylated haemoglobin levels. A significant difference was found between the connecting peptide immunoreactivity value of the group with improved glycosylated haemoglobin levels (5.0 +/- 1.0 ng/ml) and that in the group without the improvement (2.7 +/- 0.9 ng/ml).

Case report: thyrotropin-releasing hormone-induced myoclonus and tremor in a patient with Hashimoto's encephalopathy

The authors investigated the possibility of a thyrotropin-releasing hormone-related mechanism in a 43-year-old Japanese woman with Hashimoto's encephalopathy who experienced three relapses closely associated with the menstrual cycle. Her symptoms began at ovulation, worsened during the luteal phase, and improved during the menstruation phase. No abnormalities were found by brain magnetic resonance imaging and cerebral angiography. Intravenous administration of thyrotropin-releasing hormone induced symptoms of myoclonus and tremor similar to those observed during an exacerbation. The intensity and duration of involuntary movements induced by thyrotropin-releasing hormone were dose-dependent. The patient's symptoms were controlled effectively by thyroxine replacement therapy. On the basis of these findings, thyrotropin-releasing hormone may have an important role in Hashimoto's encephalopathy.

Can alpha-glucosidase inhibitors reduce the dosage of sulphonylurea compounds needed by patients with non-insulin-dependent diabetes mellitus?

The effects of treatment with an alpha-glucosidase inhibitor and a reduced dose of sulphonylurea were investigated in patients with non-insulin-dependent diabetes mellitus who had previously been treated with sulphonylurea compounds but who were hypoglycaemic at times. Treatment with a daily dose of 0.6 mg alpha-glucosidase inhibitor and a reduced dose of the previously used sulphonylurea compound for 4 weeks did not significantly affect the glycosylated haemoglobin level. The post-prandial blood-glucose concentration of the patients was unchanged after treatment compared with its value immediately before treatment but differed significantly compared with the value 4 weeks before treatment (P < 0.03); it was considered likely that this change was due to a seasonal increase in calorie intake at the end of the treatment period. Symptoms related to hypoglycaemia disappeared in all of the treated patients.

[Influence on glycemic control of improved diabetic gastroparesis by long-term cisapride therapy]

To investigate the effect on glycemic control of improving diabetic gastroparesis, we evaluated symptoms (scored), gastric motor functions (solid and liquid gastric emptying studies and electrogastrography), and glycemic control in 11 patients with diabetic gastroparesis (5 men, 6 women, 50.4 +/- 4.5 years old) before and after treatment with cisapride (15 mg/day p.o., 12 weeks). None of the patients had organic abnormalities on gastrointestinal endoscopy. The dysmotility symptom score (maximum: 18) on cisapride significantly improved from 13.1 to 4.0 (p < 0.01). Retention rates at 15 and 80 minutes after ingestion improved in a solid-food gastric emptying study using a test meal of instant noodles labeled with 37 MBq (1 mCi) technetium-99m (both p < 0.05). Liquid gastric emptying, evaluated using a sulfamethizole technique, also improved but not significantly. Electrogastrography revealed no significant changes after treatment, but the postprandial rate of normal frequency waves tended to increase. Glycemic control was assessed based on HbA1C, fructosamine and M value. There were no significant changes in glycemic control after treatment with cisapride. We conclude that long-term administration of cisapride reduced dysmotility symptoms and improved solid and liquid gastric emptying without adversely affecting glycemic control.

Determination of KA values by controlled receptor expression in Xenopus oocytes

1. In the present study we estimated the KA value of endothelin-1 (ET-1) for ETA-receptors by a new method in which the level of expression of ETA-receptors in Xenopus oocytes was altered in a controlled way. 2. Kvl.2 (a delayed rectifier type K channel) c RNA at the fixed concentration of 0.2 micro g micro l(-1) was mixed with ETA-receptor cRNA at various concentration ratios (10(-3)-3). Oocytes were examined 2-4 days after the injection of the cRNA mixtures. 3. In these oocytes, ET-1 suppressed the amplitude of Kvl.2 current in a dose-dependent manner in the range of 0.1-100 nM; the maximum inhibition produced by ET-1 was larger and the EC50 value for the inhibition by ET-1 was smaller as the mixture ratio was increased. Double-reciprocal plots of equiactive concentrations of ET-1 in 1/1- and 1/30-injected oocytes yielded a KA for ET-1 of 7.4 nM. The number of ETA-receptors in 1/30-injected oocytes was 13% of that in 1/1-injected oocytes, whereas the inhibition of the current in 1/30-injected oocytes was about 60% of that in 1/1-injected oocytes. This suggests the presence of spare receptors of ETA in the latter. 4. A saturation binding experiment estimated a KD value of 0.1 nM for ET-1 at ETA-receptors and the number of ETA-receptors in 1/30-injected oocytes was 23% of that in 1/1-injected ones. This value was not significantly different from that estimated by the above new method. However, there was a discrepancy between KA and KD, which could be due to factors unique to the expression system employed in the present study.

The voltage-dependent K+ channel (Kv1.5) cloned from rabbit heart and facilitation of inactivation of the delayed rectifier current by the rat beta subunit

We have isolated a cDNA coding for a delayed rectifier K+ channel (RBKV1.5) from rabbit heart. The amino acid sequence of RBKV1.5 displays a homology to that of other K+ channels of Kv1.5 class. Overall amino acid identity between RBKV1.5 channel and Kv1.5 channel of other species is about 85%. RNA blot analysis revealed the expression of the primary transcript in various rabbit tissues, at the highest level in both the atrium and ventricle. When expressed in Xenopus oocytes, RBKV1.5 current showed a delayed rectifier type characteristics, which was converted to rapidly inactivating currents upon coexpression with a beta subunit.

How blood pressure in patients with non-insulin-dependent diabetes mellitus is influenced by stress

The effects of reducing stress on blood pressure were investigated in 20 patients with non-insulin-dependent diabetes mellitus. An anxiolytic, fludiazepam, was administered to the patients for 12 weeks and their blood pressures and State Trait Anxiety Inventory scores at the beginning and end of treatment were compared. Systolic and diastolic blood pressures and trait and state anxiety scores were all significantly reduced during the treatment period. There was also a weak correlation between the extent of the improvement in the same anxiety score and the improvement in diastolic blood pressures.

Cardiosympathetic neuropathy is independent of cardioparasympathetic neuropathy in patients with non-insulin-dependent diabetes mellitus

The relationship between cardiosympathetic neuropathy and cardioparasympathetic neuropathy was investigated in 103 patients with non-insulin-dependent diabetes mellitus. Cardioparasympathetic nerve function was assessed by comparing electrocardiographically the expiratory and inspiratory R-R interval ratios, during a period of deep breathing, and the coefficients of variation of the R-R intervals. Cardiosympathetic nerve function was assessed by determining the uptake of [123I]metaiodobenzyl guanidine into the myocardium. The results indicate that there is no significant correlation between cardioparasympathetic and cardiosympathetic nerve function.

Comparison of D-value accuracy among Limited Spearman-Karber Procedure, Stumbo-Murphy Cochran Procedure (SMCP) and Limited SMCP

The Limited Spearman-Karber Procedure (LSKP) and Stumbo Murphy and Cochran Procedure (SMCP) are procedures to determine D-value in the Most Probable Number method (MPN). International Organization for Standardization (ISO)/Technical Committee 198/Working Group 4 contributing for the preparation of documents on biological indicator has adopted only LSKP in MPN. SMCP has been rejected due to the reason of inaccuracy without any scientific proof. Therefore, in order to confirm whether this is scientifically correct or not, Japanese delegates decide to compare both methods in simulation and experimental procedures using biological indicator and biological indicator evaluator resistometer. The result indicated that SMCP with some restrictions was not always inferior to LSKP and gave identical results.

Synthesis of 5-HT3 receptor antagonists, [11C]Y-25130 and [11C]YM060

Two high-affinity 5-HT3 receptor ligands, Y-25130 and YM 060, have been labeled with 11C for use in PET studies to measure 5-HT3 receptors. The [11C]Y-25130 was prepared by N-methylation of nor-Y-25130-BH3 complex with [11C]CH3I in the presence of K2CO3 followed by HCl hydrolysis. Likewise, N-methylation of nor-YM060 gave [11C]YM060. After HPLC separation, the decay-corrected radiochemical yield of the two 11C-labeled ligands was 34-40% based on [11C]CH3I, the specific activity was 10-12 GBq/mumol at 35-40 min from EOB, and the radiochemical and chemical purities were > 99%. In mice, the brain uptake of the two compounds was the lowest among the tissues investigated, but the level of the brain radioactivity increased with time.

Antiarrhythmic and bradycardic drugs inhibit currents of cloned K+ channels, KV1.2 and KV1.4

We investigated the effects of the antiarrhythmic drugs, quinidine, disopyramide, flecainide, clofilium, verapamil, and the bradycardic drug, bertosamil, on the currents of the cloned K+ channels, KV1.2 (IK(V1.2)) and KV1.4 (IK(V1.4)), using the Xenopus oocyte expression system. Both IK(V1.2) and IK(V1.4) were inhibited in a concentration-dependent manner by quinidine (10 microM to 1 mM), flecainide (10 microM to 1 mM), clofilium (10-300 microM), verapamil (10 microM to 1 mM) and bertosamil (10 microM to 1 mM) but not by disopyramide (10 microM to 1 mM). The inhibitory effects of clofilium, verapamil and bertosamil on IK(V1.2) were time-dependent. The decay time course of IK(V1.4) was accelerated by clofilium, verapamil and bertosamil, but decelerated by quinidine and flecainide. These results indicate that IK(V1.2) and IK(V1.4) are targets for the four antiarrhythmic drugs and the bradycardic drug.

[Interuncal distance measurements in normal controls and patients with dementia: MR imaging study]

To evaluate the utility of measuring interuncal distance (IUD) as a reflection of the limbic system, we compared the IUD of 60 dementia patients with that of 10 normal controls. We also measured the width of the intracranial compartment (W1 and W2) to correct for differences in individual brain size, and calculated the ratio of IUD/W1 and IUD/W2. IUD could not separate patients with dementia from normal controls, but there were significant differences in IUD/W1 and IUD/W2 between patients with dementia and normal controls. IUD, IUD/W1 and IUD/W2 did not correlate with Mini-Mental Examination score or ADAS score in patients with dementia. We conclude that IUD measurement is not helpful in distinguishing patients with mild stage dementia from normal aged people or as a scale for dementia. However, we suggest that IUD/W1 and IUD/W2 can discriminate between cases of mild dementia and normal aged people.

Conformational epitopes of pemphigus antigens (Dsg1 and Dsg3) are calcium dependent and glycosylation independent

The target molecule of pemphigus autoantibodies is a transmembrane desmosomal component, desmoglein 3 (Dsg3) in pemphigus vulgaris (PV) and Dsg1 in pemphigus foliaceus (PF). In this study, we examined the effects of calcium and glycosylation on the anti-genicity of the pemphigus antigens and on the generation of conformational epitopes. We used recombinant baculovirus proteins, PVIg and PFIg, which are considered to reflect accurately the native conformation of the extracellular domain of their respective proteins Dsg3 and Dsg1. These baculoproteins could immunoadsorb heterogeneous autoantibodies from the corresponding sera of PV and PF patients, completely blocking indirect immunofluorescence staining of normal human skin. Chelating calcium from the solution containing the baculoproteins using ethylenediaminetetraacetic acid (EDTA) or ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) abolished immunoadsorption by both PVIg and PFIg; however, immunoadsorption by the baculoproteins was restored after dialysis against 1 mM calcium. Nonglycosylated forms of both baculoproteins produced in the presence of tunicamycin retained their immunoadsorptive ability. Furthermore, immunoadsorption by the baculo-proteins was prevented irreversibly by treatment with low pH, high pH, and boiling, but not with the non-ionic detergent Nonidet P-40. These findings indicate that formation of the conformational epitopes on the pemphigus antigens is dependent on calcium but independent of glycosylation, and provide direct evidence that calcium plays an important role in determining the antigenic properties of the pemphigus antigens.

Cortical auditory disorder caused by bilateral temporal infarctions

We present a 55-year-old man who suddenly became afflicted with a bilateral auditory disturbance. Auditory acuity was preserved relatively well. Brainstem auditory evoked potentials (BAEPs) were normal. Middle latency auditory evoked potentials (MLAEPs) revealed the total absence of all waves. Brain computed tomography (CT) showed infarctions of the temporal lobes bilaterally, involving the superior temporal and transverse temporal gyri. The recognition of verbal and nonverbal sounds was also impaired. Brain CT, MLAEPs and auditory recognition tests were useful in diagnosing the cortical auditory disorder.

Characterization of neurotrophic factors produced by immortalized mouse brain glial cells (VR-2g)

We analyzed the neurotrophic factors secreted by immortalized fetal mouse brain glial cells (VR-2g). Concentrated conditioned medium of VR-2g cells were applied to a gel filtration column and the trophic activities of the fractions were determined by the bioassay method with primary fetal rat striatal neurons. Several peaks of neurotrophic activity were detected, the most prominent of which was found in a fraction of molecular weight 5-7 kDa. In peak fractions of molecular weight 13-26 kDa, molecules reactive to anti-NGF antibodies were detected by Western blotting only in non-reduced condition of SDS-PAGE. Anti-NGF antibodies absorbed 40% of the neurotrophic activities in the conditioned medium of VR-2g cells.