In vitro-in vivo correlation of pharmacodynamics of felodipine in essential hypertensive patients based on an ion-channel binding model

The relationship between the plasma drug concentration and the antihypertensive effect of felodipine was analyzed by an ion-channel binding model which takes into consideration the slow association/dissociation process of a drug at the calcium channel. The in vitro dissociation constant (Kd) of felodipine to the calcium channel in the heart of rats was determined, and was compared to the in vivo dissociation constant (Kd,calc) estimated by the pharmacodynamic analysis of the concentration-effect data in Japanese essential hypertensive patients obtained from literature. The relative relationship between Kd and Kd,calc of felodipine was substantially identical with eight other calcium channel blocking agents reported previously. This results suggested the possibility that we can predict the pharmacodynamic behavior of newly developed calcium channel blocking agents from the in vitro Kd value and plasma concentration-time profile in human using the ion-channel binding model.

Increased nasal mucosal blood flow, airway resistance and secretion induced by electrical stimulation of the superior salivatory nucleus in cats

We studied the effects of electrical stimulation of the superior salivatory nucleus (SSN) on the nasal blood flow, nasal airway resistance, and nasal secretion in ketamine or pentobarbital anesthetized cats. The blood flow of the nasal mucosa was measured by laser Doppler flowmetry. Similar to the effects of stimulation of the parasympathetic nerve innervating the nasal mucosa, the SSN stimulation increased the nasal blood flow, nasal airway resistance, and nasal secretion on the ipsilateral side. These responses were not accompanied by changes in contralateral nasal blood flow, ipsilateral forelimb blood flow, blood pressure, or orofacial movement. Atropine administration partially inhibited the SSN-induced nasal vasodilation without interfering with the effect on the nasal airway resistance. This vasodilatation was not affected by sympathectomy or guanethidine administration, but it was abolished by hexamethonium administration. It is suspected that the cells in the SSN control both nasal vasodilatation and secretion, and that the SSN output fibers responsible for the nasal parasympathetic control consist of both cholinergic and non-cholinergic fibers.

Activation of G protein-coupled inward rectifier K+ channels in brain neurons requires association of G protein beta gamma subunits with cell membrane

In cultured noradrenergic neurons from the rat locus coeruleus, application of recombinant G protein beta 1 gamma 2 subunits (30 nM) to the cytoplasmic side induced single channel activity similar to the somatostatin-induced single channel activity of G protein-coupled inward rectifier potassium channels (Kir (G)). In contrast, recombinant GTP gamma S-activated, myristoylated alpha i2 (100 nM) did not activate this brain Kir (G). Application of beta 1 gamma 2 C68S (30 nM or 150 nM), in which the cysteine residue fourth from the carboxyl terminus of gamma 2 was replaced by serine, failed to activate the brain Kir(G). This mutant lacks prenylation which is required for the association of beta gamma subunit with the cell membrane. Thus, our results suggest that the association of beta gamma subunit with the cell membrane is a prerequisite for activating Kir(G) channels.

Occupation of the QB-binding pocket by a photosystem II inhibitor triggers dark cleavage of the D1 protein subjected to brief preillumination

The D1 protein of the photosystem (PS) II reaction center turns over very rapidly in a light-dependent manner initiated by its selective and specific cleavage. The cleavage of D1 was studied by using a PS II inhibitor, N-octyl-3-nitro-2,4,6-trihydroxybenzamide (PNO8), as a molecular probe. The following results were obtained. (i) D1 was selectively cleaved into 23-kDa N-terminal and 9-kDa C-terminal fragments in complete darkness by PNO8 at a single site in a D-E loop connecting membrane-spanning helices D and E. (ii) The cleavage was markedly enhanced when PS II was illuminated for a brief period before the addition of PNO8 in darkness. (iii) The effect of preillumination was slowly lost during incubation in the dark, with a decay half-time of approximately 1 h at 25 degrees C. (iv) The light intensity of preillumination required for the cleavage was much lower than that required for O2 evolution. (v) The light-triggered cleavage of D1 was observed in thylakoids, PS II membranes, and PS II core particles, but not in purified PS II reaction centers. More than 60% of D1 was cleaved into the two fragments with no other by-products. (vi) The cleavage reaction revealed a marked pH dependence that was considerably different from that for inhibition of PS II activity. The results are interpreted as indicating that the binding of PNO8 to the QB-binding pocket triggers proteolytic cleavage of D1 that has been previously modified during illumination.

CT-guided transthoracic needle biopsy: a comparison between automated biopsy gun and fine needle aspiration

AIMS

We retrospectively investigated the diagnostic accuracy and complication rate of transthoracic core biopsy using an automated biopsy gun and compared the findings with those of aspiration needle biopsy.

PATIENTS AND METHODS

Seventy-three patients underwent 74 core biopsy procedures and 50 patients underwent 52 aspiration biopsy procedures. Of these, a final diagnosis was obtained in 107 lesions with surgery or clinical course. Fifteen patients in which a final diagnosis was not obtained were excluded from the study on diagnostic accuracy. Thus, in the study of diagnostic accuracy, 63 core biopsy procedures for 62 lesions are included. Core biopsy was performed with an 18 G cutting needle using an automated biopsy gun. Aspiration biopsy was performed with a 20 G aspiration needle.

RESULTS

Core biopsy yielded sufficient material in 57/63 procedures (90.5%). A correct diagnosis was obtained in 36 procedures (85.7%) for malignant leisons and a specific benign diagnosis was obtained in 11 procedures (52.4%). Aspiration biopsy yielded a correct diagnosis in 26 procedures (81.3%) for malignant leisons and in seven (46.7%) for benign lesions. The overall correct diagnosis were 75.8% and 71.7% with core biopsy and aspiration biopsy, respectively. Core biopsy gave a higher predictive rate than that of aspiration biopsy for both benign and malignant lessons (P < 0.02). Pneumothorax occurred in 18/74 (24.3%) patients with core biopsy and in 18/45 (40.0%) patients with aspiration biopsy. Of these, three with core biopsy and two with aspiration biopsy needed tube drainage. The other complication was haemoptysis, which occurred in six patients following core biopsy and in three after aspiration biopsy. All nine cases subsided spontaneously. There were no fatal complications.

CONCLUSIONS

Core biopsy with a biopsy gun increase the diagnostic accuracy with a higher histologic predictive rate and no obvious additional risk of complications.

Liver transplantation for hepatocellular carcinoma: consideration from the findings on autopsy

Extrahepatic spread of hepatocellular carcinoma was investigated in twenty autopsy cases with unresected hepatocellular carcinoma to define the appropriate patient selection criteria for liver transplantation. Diagnosis of extrahepatic spread of cancer by diagnostic imaging was not easy, and unsatisfactory prognosis after liver transplantation in patients with hepatocellular carcinoma might have been attributed to the high incidence of extrahepatic occult foci of cancer. All patients with multiple nodular, massive and diffuse tumor had extrahepatic spread of cancer. Only patients with a single nodular type tumor, no larger than 30 mm in diameter, had no extrahepatic metastasis, and these patients are the preferred candidates for liver transplantation.

Shortened telomere length in hepatocellular carcinomas and corresponding background liver tissues of patients infected with hepatitis virus

The telomere length in 20 surgically resected human hepatocellular carcinomas (HCCs) and adjacent non-cancerous livers with hepatitis virus infection were investigated. All the HCC samples examined demonstrated shorter telomere length than the corresponding non-cancerous liver tissues, the respective average values being 5.4 kbp and 8.8 kbp (P < 0.001). The shortening of telomere length was most prominent in HCCs larger than 30 mm in diameter, and in both tumors and non-cancerous livers it was more marked with hepatitis B virus as compared with hepatitis C virus infection. These results indicate that telomere shortening is associated with not only progression, but also development of HCC, and there is a possible difference in the nature of the association in patients with hepatitis viruses of B and C types.

Hypoplasia of cushion ridges in the proximal outflow tract elicits formation of a right ventricle-to-aortic route in retinoic acid-induced complete transposition of the great arteries in the mouse: scanning electron microscopic observations of corrosion cast models

BACKGROUND

The major morphologic change associated with retinoic acid (RA)-induced complete transposition of the great arteries (TGA), a congenital malformation of the heart, was investigated in a mouse model in which TGA was found in 80% of surviving fetuses.

METHODS

Corrosion casts of embryonic hearts with or without prior exposure to retinoic acid were observed under a scanning electron microscope.

RESULTS

In control hearts, indentations caused by expanded parietal and septal ridges in the outflow tract established right ventricle-to-left ventral pulmonic and left ventricle-to-right dorsal aortic routes before the aorticopulmonary septum completion. In RA-treated hearts, indentations of proximal regions of the parietal and septal ridges were small in the proximal outflow tract, whereas those in the distal regions developed well. These morphological features in the RA-treated hearts elicited right ventricle-to-right ventral aortic and left ventricle-to-left dorsal pulmonic routes in the TGA morphology.

CONCLUSIONS

Hypoplasticity of the proximal regions of parietal and septal ridges in the outflow tract is one of the primary morphological abnormalities of the RA-induced TGA.

Telomere changes in human hepatocellular carcinomas and hepatitis virus infected noncancerous livers

BACKGROUND

Telomeres, at the ends of eukaryotic chromosomes, are defined functionally as necessary for chromosome stability. Chromosome instability induced in part by loss of telomeric DNA has been considered to play a significant role in the development of human cancers. However, little is known about the status of telomeres per se during human hepatocellular carcinoma (HCC) development.

METHODS

The study was conducted to determine the length of terminal restriction fragments (TRFs) at the telomeric ends in 23 HCCs and 23 corresponding noncancerous liver tissues from the same patients harboring hepatitis virus infections, and in 5 samples of noncancerous livers without the hepatitis virus. The latter samples had been obtained as controls at surgery for metastatic liver tumors.

RESULTS

All 23 HCCs demonstrated reduction in TRF length compared with the corresponding noncancerous liver tissues with viral infection. The TRF in the latter cases also demonstrated a significant shortening as compared with the virus free control tissue, the degree being calculated to represent an average of 42 cell divisions. Reduction in TRF length in HCC samples tended to increase with the tumor diameter, although this failed to show statistical significance.

CONCLUSIONS

These results indicate that telomere shortening occurs during HCC development. The fact that this change is already evident in noncancerous liver tissues from patients with viral hepatitis suggests that it may play an important role in the associated generation of tumors.

A distinctive effect of CCCP on the transfer of erythromycin to 1-octanol: a possible model in promoting the intracellular antibiotic-accumulation through lipid in a staphylococcal cytoplasmic membrane

Movement of erythromycin (EM), a basic antibiotic solute (pKa 8.6), in an aqueous buffer (pH7.6) at 37 degrees C into 1-octanol was found approximately twofold greater in the presence of another acidic and lipophilic solute, carbonylcyanide m-chlorophenylhydrazone (CCCP), when compared with the EM-movement in the absence of CCCP. CCCP appears to behave just like a carrier of EM, besides being a well-known inhibitor, such as the uncoupling agent of oxidative phosphorylation. The probability is discussed that such an analogous event takes place in the lipid layers of a bacterial-cell membrane.

Different immunosuppressive effects of liposomal FK506 in liver and kidney transplantation

The efficacy of liposomal FK506 was compared between a canine liver transplantation model and a canine kidney transplantation model. The present study revealed that liposomal FK506 increased immunosuppressive efficacy of FK506 in liver transplantation but decreased in kidney transplantation. Because liposomal FK506 increased FK506 levels in the liver and spleen, and decreased FK506 levels in the kidney, it was suggested that enhanced immunosuppressive efficacy in liver transplantation should be attributed to the local immunosuppressive effects in the hepatic allograft rather than effective suppression of splenocyte activity.