Sources of Ca2+ in relation to generation of acetylcholine-induced endothelium-dependent hyperpolarization in rat mesenteric artery

1. The aim of the present study was to identify the sources of Ca²⁺ contributing to acetylcholine (ACh)-induced release of endothelium-derived hyperpolarizing factor (EDHF) from endothelial cells of rat mesenteric artery and to assess the pathway involved. The changes in membrane potentials of smooth muscles by ACh measured with the microelectrode technique were evaluated as a marker for EDHF release.
2. ACh elicited membrane hyperpolarization of smooth muscle cells in an endothelium-dependent manner. The hyperpolarizing response was not affected by treatment with 10 μM indomethacin, 300 μM N^G-nitro-L-arginine or 10 μM oxyhaemoglobin, thereby indicating that the hyperpolarization is not mediated by prostanoids or nitric oxide but is presumably by EDHF.
3. In the presence of extracellular Ca²⁺, 1 μM ACh generated a hyperpolarization composed of the transient and sustained components. By contrast, in Ca²⁺-free medium, ACh produced only transient hyperpolarization.
4. Pretreatment with 100 nM thapsigargin and 3 μM cyclopiazonic acid, endoplasmic reticulum Ca²⁺-ATPase inhibitors, completely abolished ACh-induced hyperpolarization. Pretreatment with 20 mM caffeine also markedly attenuated ACh-induced hyperpolarization. However, the overall pattern and peak amplitude of hyperpolarization were unaffected by pretreatment with 1 μM ryanodine.
5. In the presence of 5 mM Ni²⁺ or 3 mM Mn²⁺, the hyperpolarizing response to ACh was transient, and the sustained component of hyperpolarization was not observed. On the other hand, 1 μM nifedipine had no effect on ACh-induced hyperpolarization.
6. ACh-induced hyperpolarization was nearly completely eliminated by 500 nM U-73122 or 200 μM 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, inhibitors of phospholipase C, but was unchanged by 500 nM U-73343, an inactive form of U-73122. Pretreatment with 20 nM staurosporine, an inhibitor of protein kinase C, did not modify ACh-induced hyperpolarization.
7. These results indicate that the ACh-induced release of EDHF from endothelial cells of rat mesenteric artery is possibly initiated by Ca²⁺ release from inositol 1,4,5-trisphosphate (IP₃)-sensitive Ca²⁺ pool as a consequence of stimulation of phospholipid hydrolysis due to phospholipase C activation, and maintained by Ca²⁺ influx via a Ni²⁺- and Mn²⁺-sensitive pathway distinct from L-type Ca²⁺ channels. The Ca²⁺-influx mechanism seems to be activated following IP₃-induced depletion of the pool.

     

Efficacy of postoperative adjuvant therapy for stage ilia breast cancer: Futraful vs futraful+tamoxifen for er-positive patients and futraful vs futraful + adriamycin for er-negative breast cancer

A multi-center, randomized controlled collaborative study was conducted in 310 institutions located throughout Japan for 3 years and 9 months from February 1985 until October 1988 to evaluate the efficacy of post-operative adjuvant therapy for patients who had previously undergone curative surgery for treatment of Stage IIIa breast cancer. Patients with estrogen receptor-positive [ER( + )] breast cancer were treated with two types of regimens, ie, cyclophosphamide + adriamycin + fluorouracil (CAF; 2 cycles) + Futraful (FT) or CAF (2 cycles) + FT + tamoxifen (TAM), and the clinical benefit of additional use of TAM was evaluated. Of the 509 ER( + ) patients registered for the trial, 473 patients (92.9%) were eligible for evaluation. The 5-year survival rate was 77.2% for the CAF + FT group and 74.6% for the CAF + FT+TAM group, and the 5-year disease-free survival rate was 56.7% for the CAF+FT group and 59.2% for the CAF + FT + TAM group. Neither the survival rate nor the disease-free survival rate differed significantly between the groups. Analyses by factor revealed that the 5-year disease-free rate for lymph node-negative patients in the CAF + FT + TAM group was significantly higher than that for the corresponding patients in the CAF + FT group. No differences were noted in the incidence of adverse reactions between the two treatment groups, other than an increase in LDH (the frequency of which was higher in the CAF + FT+TAM group than in the CAF + FT group). Patients with estrogen receptor-negative [ER( -)] breast cancer were treated with two types of regimens, ie, CAF + FT or CAF + FT + adriamycin (ADR), and the clinical benefit of the combined use of intermittent doses of ADR was evaluated. Of the 514 ER(-) patients registered in the trial, 478 (93.0%) were eligible for evaluation. The 5-year survival rate was 64.9% for the CAF + FT group and 63.0% for the CAF + FT + ADR group, and the 5-year disease-free survival rate was 59.2% for both CAF + FT and CAF + FT + ADR groups. Neither the survival rate nor the disease-free survival rate differed significantly between the groups. There were no significant differences between these groups in analyses by nodal or menopausal status. The incidences of adverse reactions including anorexia, nausea/vomiting and alopecia were higher in the CAF + FT+ADR group than in the CAF + FT group.     

Mutchinick syndrome in a Japanese girl

We report on a 7-year-old Japanese girl with Mutchinick syndrome, a rare congenital malformation syndrome described in a pair of Argentinean sisters and a pair of German brothers; both originating from the same geographic region in the former East Prussia. The girl we describe had most of the clinical manifestations of the syndrome, including growth and developmental retardation, and craniofacial anomalies with microcephaly, hypertelorism, a broad straight nose, low-set malformed ears, and a wide, tented mouth. She also had the following hitherto undescribed manifestations: ventricular septal defect, palmoplantar hyperkeratosis, bilateral partial soft-tissue syndactyly of second and third toes, and megaloureters. The occurrence of the syndrome in a Japanese girl indicates that the syndrome is not restricted to the descendants of individuals from a confined region in northeastern Europe.     

The concept of the digital morgue as a 3D database

The concept of the construction of a 3-dimensional database of a body structure, or a digital morgue, and its advantages to the field of forensic medicine was proposed. The digital morgue stores the body structure of each case as a 3D data set of sectioning planes of the whole body obtained from computer tomograms or magnetic resonance imaging figures. Furthermore, the medical virtual reality technique makes it possible to perform a simulated autopsy of the body in the digital morgue (virtual autopsy). Therefore, in the digital morgue, retrospective observation and quantitative analysis of the structural damage of the body are possible using high-dimensional medical imaging and medical virtual reality.     

Stuck valve leaflet detected by intraoperative transesophageal echocardiography.

We encountered a rare complication of mitral valve replacement with the CarboMedics prosthesis: a "stuck" leaflet detected by transesophageal echocardiography even though weaning from cardiopulmonary bypass had been uneventful. The patient was immediately managed without significant problems. We emphasize the importance of performing routine intraoperative transesophageal echocardiography in valve replacement as well as in valve repair, from the initial phase of operation.     

Long-term follow-up of an individual with vitamin B6-dependent seizures

We report on a 31-year-old female with vitamin B6-dependent seizures whose seizure onset was in the neonatal period. Her elder brother had the same disorder and died in infancy. Administration of vitamin B6 was initiated in the postnatal period. At the age of 12 years 1 month, 2 months after withdrawal of vitamin B6, visual seizures began to occur frequently. Myoclonic seizures and occasional generalized convulsive seizures were also observed. At the same time, photoparoxysmal response and spontaneous diffuse spike-wave bursts were seen on her EEG. Myoclonic seizures were provoked by intermittent photic stimulation during the EEG. It is distinctive that visual seizures were one of the main seizure types in this patient, that her clinical course was relatively benign, and that she has normal intellectual outcome.     

n-Hexane neuropathy caused by addictive inhalation: clinical and electrophysiological features

To assess the clinical and electrophysiological features of n-hexane neuropathy caused by addictive inhalation, 4 patients were studied in the progressive phase. The neurological manifestations were characterized by subacute predominantly motor polyneuropathy and disease progression despite discontinuance of the chemicals, which were similar to those reported in industrial exposure, although with a severer degree associated with anorexia and body weight loss. Electrophysiological studies showed that all showed multifocal conduction block and profound conduction slowing, as well as features of axonal degeneration. Sural nerve biopsy showed axonal loss, axonal swelling, and thin myelin probably due to retraction by axonal swelling. n-Hexane abuse causes severe subacute polyneuropathy. The mixed axonal and demyelinating electrophysiological features were consistent with peculiar pathological findings. Conduction block, probably due to paranodal myelin retraction or ongoing wallerian degeneration, is very frequent and could be responsible for the clinical deficits, especially in the early phase of illness.     

Identification of binding sites of bopindolol and its two metabolites with beta1-adrenoceptors by molecular modeling: comparison with beta2 adrenoceptors

This study was designed to examine the importance of interaction in the bindings of nonselective beta-blockers to beta1-adrenoceptors (beta1-ARs) as compared with beta2-ARs, using molecular modeling. The beta-blockers used in this study were bopindolol [4-(benzoyloxy-3-t- butylaminopropyl)-2-methylindol hydrogen malomate], its two metabolites [18-502 - hydrolyzed bopindolol or 4-(3-t-butylamino-2-hydroxypropoxy)-2-methyl indole - and 20-785 - 4-(3-t-butylaminopropoxy)-2-carboxyl indole], and propranolol. Molecular modeling was performed on an Indigo2 workstation (Silicon Graphic) using Discover/Insight II (Molecular Simulations) software. Through molecular modeling, possible binding sites for these drugs were suggested to lie between helices 3, 4, 5, and 6 of the beta1-AR. The amine, benzoic acid, indole methyl, t-butyl, phenyl, and indole functional groups of bopindolol possibly interact with Asp138 (transmembrane - TM - 3), Ser190 (TM 4), Ala343 (TM 6), Val137 (TM 3), Pro339 (TM6), Cys336 (TM 4), Leu237 (TM 5), and Pro236 (TM 5) of beta1-AR, respectively, by either hydrogen bonding or hydrophobic interactions. In addition, 18-502, 20-785, and propranolol also interacted with sites at the same positions as those of beta2-ARs. Thus, the results of the present study suggested that although Ala343 and Val137 of beta1-AR among these amino acids were different from those of beta2-AR, the interactions at the same sites between ligands and amino acids of beta1-AR as those of beta2-ARs may occur because these drugs are nonselective.     

Inhibitory effect of triterpenes from Crataegus pinatifida on HIV-I protease.

The methanol extracts of the leaves of Crataegus pinnatifida showed potent inhibitory activities against HIV-1 protease at a concentration of 100 micrograms/ml. The subsequent fractionation and isolation of the extract gave two active compounds. Their structures were identified as uvaol (1) and ursolic acid (2) by spectral data. These active compounds inhibit HIV-1 protease with IC50 values of 5.5 and 8.0 microM, respectively.     

Flavonoids from Cleome droserifolia suppress NO production in activated macrophages in vitro.

The effect of an Egyptian medicinal plant, Cleome droserifolia (Forssk.) Del. on nitric oxide (NO) production in bacillus Calmette-Guérin-induced mouse peritoneal macrophages activated by lipopolysaccharide was investigated in vitro. The methanol extract of C. droserifolia reduced the NO production, and two flavonoids were isolated as the active components. The new one was determined to be 5,4'-dihydroxy-6,7,8,3',5'-pentamethoxyflavone (1) and the other was identified as 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone (8-methoxycirsilineol; 2). Compound 1 concentration-dependently suppressed the NO production and was effective at a non-toxic concentration (12.5 micrograms/ml). The suppressive activity of 2 was weaker than that of 1.