Possible mechanisms related to contraction of the bovine iris sphincter in the presence of acetylcholine and carbachol

Using tension-recording methods, we compared the effects of acetylcholine (Ach) and carbachol on the bovine iris sphincter. The isolated muscle strips were mounted in a 0.2 ml organ bath, through which Krebs solution at 36 °C flowed continuously. There was a tenthousandfold difference in potency between carbachol and Ach in this tissue. Neostigmine or eserine, acetylcholinesterase (AchE) inhibitors, produced a larger contraction of the muscle than did Ach. Ach-induced contractions were potentiated by low doses of anti-AchEs and were inhibited by atropine.This in vitro study suggests that Ach and/or endogenous chemical agents may be spontaneously released from tissues and that AchE activities in this tissue strongly inhibit or mask the Ach action, probably in order to protect the nerve terminals from released Ach.     

DIFFERENCES IN ENDOTHELIUM-DEPENDENT RELAXATION IN VARIOUS ARTERIES FROM WATANABE HERITABLE HYPERLIPIDAEMIC RABBITS WITH INCREASING AGE

1. Endothelium-dependent relaxation in response to acetylcholine (ACh) and the calcium ionophore A 23187 was examined in aorta, coronary, basilar and renal arteries isolated from Watanabe heritable hyperlipidaemic (WHHL) rabbits of 2, 6 and 12 months of age, with normolipidaemic heterozygous WHHL rabbits as controls. 2. In the rings of WHHL rabbit aortae and coronary arteries preconstricted with vasoconstrictors, endothelium-dependent relaxation in response to ACh was attenuated with age compared to the heterozygous WHHL rabbits. A significant negative correlation was found between the total cholesterol content and the relaxation response to ACh in the aortae or coronary arteries from 6 and 12 month old WHHL rabbits. 3. In the rings of basilar arteries, endothelium-dependent relaxations to ACh were not modified with age. Similarly, in the rings of renal arteries, the relaxation response to ACh was not changed with age, but in the 6 and 12 month preparations, after the age of 6 months, a contraction following the relaxation appeared at higher concentrations of ACh (10^?7 to 10^?6 mol/L). The contraction was endothelium-dependent and inhibited by indomethacin. 4. A 23187-induced endothelium-dependent relaxations were also markedly attenuated in the aorta and significantly in the coronary artery with age. 5. Endothelium-independent relaxation to sodium nitroprusside was not changed in all arteries from WHHL rabbits of different ages. 6. These findings indicate that in the aorta and coronary artery of the WHHL rabbit, the endothelium-dependent relaxation to ACh and A 23187 becomes impaired with increasing age (i.e., with the progression of cholesterol deposition in the arterial wall) but is preserved in the basilar and renal artery.     

Involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters in neonatal rat spinal cord.

1. The possible involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters was examined in the spinal cord of the neonatal rat. 2. The magnitude of substance P (SP)- or neurokinin A (NKA)-evoked depolarization of a lumbar ventral root in the isolated spinal cord preparation was increased by a mixture of peptidase inhibitors, consisting of actinonin (6 microM), arphamenine B (6 microM), bestatin (10 microM), captopril (10 microM) and thiorphan (0.3 microM). The mixture augmented the response to NKA more markedly than that to SP. 3. In the isolated spinal cord-cutaneous nerve preparation, the saphenous nerve-evoked slow depolarization of the L3 ventral root was augmented by the mixture of peptidase inhibitors in the presence of naloxone (0.5 microM) but not in the presence of both naloxone and a tachykinin receptor antagonist, GR71251 (5 microM). 4. Application of capsaicin (0.5 microM) for 6 min to the spinal cord evoked an increase in the release of SP from the spinal cord. The amount of SP released was significantly augmented by the mixture of peptidase inhibitors. 5. Synaptic membrane fractions were prepared from neonatal rat spinal cords. These fractions showed degrading activities for SP and NKA and the activities were inhibited by the mixture of peptidase inhibitors. The degrading activity for NKA was higher than that for SP and the inhibitory effect of the mixture for NKA was more marked than that for SP. Although some other fractions obtained from homogenates of spinal cords showed higher degrading activities for SP, these activities were insensitive to the mixture of peptidase inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of renal pelvic carcinoma in situ]

A 72-year-old female visited our hospital with the complaint of macroscopic hematuria on Jan. 29, 1990. Cystoscopic examination revealed hematuria flowing out from the left ureteral orifice. A 1 cm mass was found in the left upper calyx by retrograde pyelography (RP). Urine cytology obtained by RP was class IIIb. Later, the mass was found in the left middle calyx by CT. Repeated RP revealed no mass and the wall of the left upper calyx was irregular. Washing cytology from the left renal pelvis was class V. Left total nephroureterectomy was performed on Feb. 2, 1990. Macroscopically, no tumor mass was apparent. Microscopically, transitional cell carcinoma in situ was widely spread from the left renal pelvis to the middle ureter. The preoperative upper calyceal mass was thought to have been a blood clot. At twelve months after the operation, there has been no evidence of tumor recurrence.     

Clinical studies on morphological changes in the prostate in patients with benign prostatic hypertrophy after antiandrogen therapy--by means of transrectal ultrasonotomography]

Transrectal ultrasonotomography is useful in following patients with benign prostatic hypertrophy, because prostatic shape and weight are precisely assumed. We studied the effect of chlormadinone acetate (CMA) on benign prostatic hypertrophy. CMA (50 mg/day) was administered to 30 patients with benign prostatic hypertrophy. Weight reduction over 10% of the gland was noticed in 24 cases (80%). Mictional conditions were improved in 70% subjectively and in 71.4% objectively. However, the number of nocturia decreased in only 18.9%. Reduction rate of the weight was unrelated with the weight of prostate before administration of CMA. Duration of administration of CMA and the reduction rate were estimated. There was no definite difference in reduction rate for the first 15 months, but there was a slightly high reduction rate after administration of CMA for more than 24 months. In 3 cases, the shape and weight of prostate were studied after discontinuation of CMA. The size of prostate showed a tendency to increase gradually.     

A case of double cancer: renal cell carcinoma and transitional cell carcinoma of urinary bladder

This is a case report on a patient with double cancer of kidney and urinary bladder. The patient was a 65-year-old female, and she was admitted with the chief complaint of gross hematuria and right flank pain. After careful examinations, she was diagnosed with right nonfunctioning kidney caused by invasive bladder cancer. Computerized tomography incidentally revealed a mass in the upper pole of the left kidney. Selective left renal arteriography showed stretched arteries and irregularity and tortuosity of the smaller vessels. She was diagnosed with double cancer of bladder and left kidney. Owing to the damage of the right renal function, left partial nephrectomy, total cystectomy, right nephroureterectomy and left ureterocutaneostomy were performed. According to DMSA scintigraphy measured 15 days later, the uptake value of the left kidney was 13.25%, compared to the preoperative value of 25.62%. To date, this case is 36th reported case in Japan.     

Biocompatibility of zirconia dispersed hydroxyapatite ceramics

Because of the lack of adequate strength and toughness, hydroxyapatite (HA) ceramic can not be used for a substitute for a bone and joint despite its excellent affinity for the bone. The present authors have succeeded in producing a new type of HA ceramic containing zirconia. This new ceramic material is superior to ordinary HA ceramic in quality and exceeds compact bone in bending strength and fracture toughness. The Young's modulus was about 3-4 times greater than that of compact bone. The new ceramic material contained either 1.6 or 50% of zirconia by volume and was produced using a special technique to disperse the metal dioxide. In order to assess their affinity for the bone, the new ceramic materials were implanted into rabbit femurs. Sections of the bones removed at different times after operation were prepared without decalcification and subjected to optical microscopy, scanning electronmicroscopy (SEM), and electron-probe X-ray microanalyser (EPMA). The formation of direct chemical bonds with the bone was seen without intervening membrane. Thus, the new ceramic material was shown to have an excellent affinity for the bone, comparable to that of ordinary HA ceramic.     

Cone dysfunction and supernormal scotopic electroretinogram with a high-intensity stimulus

An unusual form of scotopic electroretinogram with a bright white stimulus, which consisted of a rectangular a-wave of normal amplitude and a b-wave of supernormal amplitude, was recorded in three patients with cone dysfunction. In addition to poor visual acuity, abnormal color vision and reduced amplitude of the photopic electroretinogram, these patients showed a 2-log unit elevation of the dark-adaptation threshold. Funduscopic examination and fluorescein angiography revealed fine granular pigment disturbances at the mascula. The relationship between the response of the dark-adapted electroretinogram versus stimulus intensity was unique to these patients. The b-wave thresholds were elevated by 1 log unit. The b-waves were reduced in amplitude and markedly delayed in implicit time to dim stimuli, but supernormal in amplitude and normal in implicit time to bright stimuli.Abbreviations GMP guanosine monophosphate     

Two cases of subcortical hemorrhage with asymptomatic occlusion of the main trunk of cerebral artery

We report two cases of asymptomatic occlusion of the main trunk of the cerebral artery associated with subcortical hemorrhage in the area fed by collateral circulation. The first patient, a 51-year-old female who had suffered from untreated hypertension for 20 years, was hospitalized in a state of coma. Computed tomography (CT) revealed a subcortical hemorrhage in the right parietal lobe as well as subdural and subarachnoid hemorrhages. Cerebral angiography disclosed occlusion of the right internal carotid artery at its origin. The region normally supplied by the right anterior (ACA) and middle cerebral (MCA) arteries was supplied instead by the posterior cerebral artery via leptomeningeal anastomosis. The hematoma was removed and the patient was discharged 1 month later. The second patient was a 54-year-old female who had suffered from uncontrollable hypertension for 27 years and was hospitalized after sudden development of stupor, right hemiparesis and motor aphasia. CT demonstrated a subcortical hemorrhage in the left parietal lobe. Cerebral angiography disclosed occlusion of the left MCA at its origin. The area normally fed by the left MCA was supplied instead by the ACA by way of leptomeningeal anastomosis. One month after operation the patient was transferred to another hospital for rehabilitation of right hemiparesis. Both of these middle-aged women had long-standing hypertension. The hemorrhages were thought to result from rupture of the leptomeningeal anastomosis, which had developed as collateral vessels. It is probable that the relatively weak leptomeningeal anastomosis could no longer withstand the increased blood flow brought on by the hypertension.