Heterogeneous distribution of muscarinic receptors in the rabbit saphenous artery.

1. The properties of the muscarinic receptors in the rabbit saphenous artery were determined from electrical and mechanical responses of smooth muscle cells produced by acetylcholine (ACh). The inhibitory action of atropine and pirenzepine on the ACh-induced responses was also studied. 2. ACh produced a transient hyperpolarization of the membrane and inhibited the noradrenaline (NA)-induced contraction. These effects of ACh were apparent only when the endothelial cells were intact. 3. The ACh-induced transient hyperpolarization was antagonized by atropine or pirenzepine, with similar potencies (the ID50 values were about 2 x 10(-8) M for both antagonists). 4. The ACh-induced inhibition of the contraction to NA was antagonized by atropine more preferentially than by pirenzepine (the ID50 values were 2 x 10(-8) M for atropine and 10(-6) M for pirenzepine). 5. The excitatory junction potential (e.j.p.) evoked by perivascular nerve stimulation was inhibited by ACh (above 10(-8) M). The ACh-induced inhibition of the e.j.p. was antagonized by atropine more preferentially than by pirenzepine (the ID50 values were 3 x 10(-8) M for atropine and 6 x 10(-6) M for pirenzepine). 6. It is concluded that in the rabbit saphenous artery, two subtypes of muscarinic receptor (M1 and M2) are located on the endothelial cells. Stimulation of each subtype releases a different substance, i.e., a hyperpolarizing substance (M1-subtype) or a relaxant substance (M2-subtype). In prejunctional nerve terminals, the muscarinic receptors responsible for inhibiting the release of transmitter substances are of the M2-subtype.     

Renal glutathione depletion and nephrotoxicity of cadmium-metallothionein in rats

Renal glutathione (GSH) concentrations were reduced approximately 80% at 4 hr after a single injection of buthionine sulfoxime (BSO) (4 mmol/kg body wt) and remained reduced for at least 16 hr in male rats. Following BSO injection, rats were injected with a nephrotoxic dose of cadmium-metallothionein (Cd-MT) (0.3 mg Cd as Cd-MT/kg body wt) and killed 1, 4, or 12 hr later. Damage to the kidney was assessed histologically and by measurement of p-aminohippuric acid (PAH) uptake into renal cortical slices. Although the renal accumulation of Cd following Cd-MT injection was significantly lower in BSO-pretreated rats as compared to nonpretreated rats, the damage to kidney was more severe. At 4 and 12 hr, both Cd-MT-induced inhibition of PAH uptake and morphological damage were significantly increased in BSO-pretreated rats. In certain experiments, the induction of renal intracellular MT synthesis by zinc pretreatment slightly decreased the renal toxicity of Cd-MT in the BSO-treated rats. The results demonstrate that although GSH depletion decreases the renal accumulation of Cd in rats injected with Cd-MT, the nephrotoxicity of Cd-MT is increased. Preinduction of MT in the kidney can only partially overcome this increase in toxicity. Therefore both GSH and intracellular MT levels can influence the renal toxicity of injected Cd-MT.     

Pseudoaneurysm of the cortical artery associated with chronic subdural hematoma--a consideration on traumatic middle cerebral artery aneurysm

A 62-year-old man was admitted to our hospital, since chronic subdural hematoma was showed after he complained of mild headache and nausea. Two years ago he had head trauma at the left parietal region after drinking. On admission there was no paresis and mild choked disc is detected. Computed tomography with contrast enhancement showed abnormal enhancement and left chronic subdural hematoma. Cerebral angiography showed an aneurysm of the angular artery. Operation was done and the aneurysm was trapped. Aneurysmal wall was histologically a pseudoaneurysm. Post-operative result was good. We considered the relationship between the cortical pseudoaneurysm and chronic subdural hematoma. We reviewed the traumatic middle cerebral artery aneurysm in the literature, 56 cases.     

The effects of long term Tranilast administration on bronchial hypersensitivity in asthmatics

Tranilast is an oral antiallergic agent developed in Japan. This study investigated the effect of prolonged administration of Tranilast on the bronchial sensitivity of 18 asthmatic subjects. They were treated for either less than 3 months or more than 3 months continuously. Methacholine loading testing was used to assess bronchial reactivity, and the respiratory parameters were recorded on an Astograph. Patients treated for longer than 3 months showed a significant decrease in bronchial sensitivity (p less than 0.05). The anticholinergic and bronchodilatory properties of Tranilast were also investigated in 8 subjects. No significant anticholinergic or bronchodilatory effects were observed following a single oral dose of 100 mg of Tranilast.     

Correlation of 99mTc-MDP scintimetry and histology in cervical hip fracture

In 20 cases of fresh cervical hip fracture, treated with primary prosthetic replacement, preoperative 99mTc-MDP scintimetry was compared with histologic findings of the extracted femoral heads. The radionuclide uptake was classified into three types according to the activity distribution; overall increase, focal decrease, and overall decrease. Histologically, the location and extent of ischemic necrosis in the femoral heads were closely related to the distribution of decreased activity.     

Electrochemotherapy significantly inhibits the growth of colon 26 tumors in mice

Electrochemotherapy is a novel antitumor treatment involving the systemic administration of bleomycin followed by the delivery of electrical pulses to the tumor. The present study investigates the effects of electrochemotherapy on the growth of colon 26 cells inoculated subcutaneously into the backs of BALB/c mice. The mice were divided into the following four experimental groups: 20 that received no further treatment after the inoculation of colon 26 cells (control group); 20 that received 500 μg of bleomycin intraperitoneally 7 and 9 days after the inoculation (BLM group); 20 that received electric pulses to the tumor 7 and 9 days after the inoculation (EP group); and 30 that received electrochemotherapy 7 and 9 days after the inoculation (ECT group). During 28 days of observation, no deaths due to tumor progression occurred in the ECT group, but there were 18 in the control group, 11 in the BLM group, and 18 in the EP group. While weight loss was observed in all groups, it was most remarkable in the control group. Tumor growth was significantly inhibited in the ECT group, compared to the other experimental groups (P<0.01). The results of this study demonstrated that electrochemotherapy significantly inhibited the growth of colon 26 tumors in mice, without causing any remarkable adverse effects.