Ca2+-dependent binding of [3H]calmodulin to the microsomal fraction of brain

The binding of calmodulin to a brain microsomal fraction rich in synaptic membranes and vesicles was studied using 3H-labeled calmodulin. The binding was Ca2+-dependent and highly specific to calmodulin since it was competitively displaced only by unlabeled calmodulin and not by 200-4,000-fold excess of other proteins that included troponin-C and S-100 protein. Within the physiological pH range, the specific binding, defined as the amount of bound [3H]calmodulin which is displacable by the addition of an excess of unlabeled calmodulin, agreed well with the Ca2+-dependent binding defined as the difference between the total binding in the presence of Ca2+ and the binding obtained with EGTA in place of Ca2+. Both binding activities appeared to be greatest at about pH 7.0. The binding, either specific or Ca2+-dependent, is a calmodulin concentration-dependent saturable process. The dose-dependent curve obtained for increasing concentrations of [3H]calmodulin agreed well with that obtained for mixtures of a fixed concentration of [3H]calmodulin and increasing concentrations of unlabeled calmodulin over the entire concentration range examined. The results serve as the basis for using [3H]calmodulin in binding studies. Scatchard plot analysis of the curve gave two different Kd values for calmodulin, 8.2 X 10(-8) and 5.3 X 10(-7) M. The corresponding maximum binding capacities were 1.0 X 10(14) and 1.6 X 10(14) calmodulin molecules per mg of microsomal protein, respectively. The binding ability of the microsomal fraction was completely abolished by prior treatment with proteolytic enzymes.

Postpartum capillary leak syndrome. A case report

A 29-year old healthy woman suddenly developed hypovolemic shock, anasarca, pleural effusion, and ascites in the postpartum period. Plasma leakage was thought to be caused by generalized increased capillary permeability. She was treated successfully with massive plasma transfusions, administration of norepinephrine, and early institution of respiratory support. The patient has not developed a similar episode during 1 yr of follow-up.

[Electrophysiologic effects of calcium channel blocking agents on the sinus node function in anesthetized dogs (author's transl)]

The electrophysiologic effects of calcium channel blocking agents, diltiazem, verapamil and nifedipine, on the sinus node function were examined in 43 anesthetized closed-chest dogs in comparison with the effects of propranolol. The parameters of sinus node function, i.e. sinus cycle length (SCL), sinus node recovery time determined by overdrive suppression (SRT), both of which are thought to reflect sinus node automaticity, and sinoatrial conduction time estimated by Strauss method (SACT), were evaluated. Intravenously administered diltiazem (0.2 mg/kg), verapamil (0.1 mg/kg) and propranolol (0.1 approximately 0.2 mg/kg) increased SCL and SRT significantly although the increase of these parameters induced by nifedipine (0.03 mg/kg) was not statistically significant. The calcium channel blocking agents did not significantly affect SACT in contrast with propranolol which showed a prolonging effect. Thus calcium channel blocking agents suppressed sinus node automaticity yet had little effect on sinoatrial conduction.

[Studies on the viability of trophoblast after termination of various kinds of pregnancies (author's transl)]

Although normal value of hCG (LH level) does not necessarily indicate eradication of viable trophoblast, its confirmation has been demonstrated as a clinically useful guide for the probable prevention of choriocarcinoma after hydatidiform mole by Takeuchi et al. Choriocarcinoma preceded by other pregnancies than hydatidiform mole which has the highest risk for choriocarcinoma has drawn more attention than before in connection with the decrease of postmolar choriocarcinoma. So that I have studied the regression rate of urinary gonadotropin (hCG) after the termination of various kinds of pregnancies. In 2,433 cases of induced abortion, 695 cases of spontaneous abortion, 1,724 cases of term delivery and 43 cases of hydatidiform mole, their urinary hCG were determined to the level of physiological range of LH. The rate of hCG regression was in the order of term delivery, spontaneous abortion, induced abortion and hydatidiform mole. The younger was the gestational age of trophoblast, the slower was the regression of hCG. At one month after the termination of pregnancy, 80.1%, 11%, 0.3%, 8% and 4.1%, and at two month 55.8%, 1.6%, 0.5%, 4% and 0.5% for hydatidiform mole, induced abortion of less than 12 week of gestation, spontaneous abortion of less than 12 week of gestation, spontaneous abortion of between 13 and 20 week of gestation respectively still showed abnormal hCG value. One percent of induced abortion at 5 month, 4% of spontaneous abortion at 3 month, 0.3% of term delivery at 4 month still maintained abnormal titer. No malignant sequelae in patients under the investigation have ever been observed in the follow up period between 3 and 8 years.

Adjuvant endocrine therapy for operable breast cancer using the antiestrogen mepitiostane: a preliminary report

The steroidal antiestrogen, mepitiostane (Thioderone, 2 alpha, 3 alpha-epitio-5 alpha-androstane-17 beta-yl 1-methoxycyclopentyl ether) was administered orally to 182 patients with operable breast cancer as an adjuvant therapy after mastectomy intermittently for 3 years. The mean duration of follow-up was 32 months (6 approximately 42 months). The treatment failure ratio and the time distribution of failure among those given mepitiostane were compared with those of 96 patients treated with mitomycin C. There was a recurrence of malignancy in 11.5% (21/182) of patients treated with mepitiostane and in 15.6% (15/96) of patients given mitomycin C. The recurrence rates of the postmenopausal patients treated with mepitiostane and those treated with motomycin C were 3.8% (3/80) and 17.6% (18/102), respectively. In contrast, the malignancy relapsed in 24.0% (14/39) and in 2.4% (1/42) of the premenopausal patients given mepitiostane and those given mitomycin C, respectively. Estrogen and progestrone receptors (ER, PgR) were assayed in some of the primary breast cancers. Although there was no difference in recurrence rate between the ER-positive and -negative cases, the recurrence rate of the patients with ER(+)PgR(+) tumors treated with mepitiostane was shown to be lower than those with ER(+)PgR(-) or ER(-)PgR(-) tumors. The antiestrogen mepitiostane may thus be useful in postmenopausal patients, in whom the adjuvant chemotherapy was less effective in preventing the recurrence of malignancy.

Mammary carcinogenic effect of low-dose fission radiation in Wistar/Furth rats and its dependency on prolactin

The mammary carcinogenic effect in rats of low-dose fission radiation and its dependency on prolactin were studied. A total of 141 female W/Fu rats were exposed to 4.8, 8.9, or 19.5 rads of fission radiation that had both fision neutrons of 2.0 million electron volts (MeV) and gamma ray components similar to those produced by the Hiroshima bomb. Only 1 of 48 rats (2.0%) developed mammary tumor (MT) after irradiation alone, whereas 20 of 48 rats (41.6%) developed MT's if prolactin was supplied shortly after irradiation by means of grafting of the prolactin-secreting pituitary tumor. Furthermore, MT's occurred in 11 of 45 rats (24.4%) treated with prolactin as late as 12 months after irradiation, which suggested the long-term survival of radiation-induced dormant MT cells. A correlation was found between the development of MT and the elevation of serum prolactin level; most MT's appeared shortly after the grafted mammotropic pituitary tumor became palpable. The growth of MT's appeared to be promoted by prolactin in collaboration with ovarian hormones; the growth of adenocarcinomas was dependent on prolactin and ovarian hormones, whereas the growth of fibroadenomas appeared to be less hormone-dependent. Much higher biologic effectiveness, especially in the low-dose range, was found with 2.0-MeV fission neutrons compared with 14.1-MeV fast neutrons or 180-kilovolt peak X-rays in rat mammary carcinogenesis.

Estimation of RBEs of thermal neutrons and reactor beam in the thermal neutron field for biomedical purposes

The radiation field and reactor beam were prepared to measure the RBE of thermal neutrons and reactor beam in Kyoto University Reactor (KUR). The RBE of reactor beam with low contamination of gamma ray (1.8 x 10(11) n cm-2R-1) and high Cd ratio (5000) on HeLa cells was 1.26 at the surviving fraction of 0.90, and the estimated RBE of thermal neutrons was 5.50 at the same surviving fraction.

A cause of paired ventricular extrasystoles

Eight patients with ventricular extrasystoles are reported in whom coupling intervals of the extrasystoles to the proceding sinus beats were variable and in whom paired ventricular extrasystoles were occasionally seen. In all patients, paired ventricular extrasystoles were initiated only by comparatively late coupled ventricular extrasystoles. However, the interval between the first and the second of these paired extrasystoles was always much shorter than the coupling interval of this first extrasystole to the preceding sinus beat, so that the latter extrasystole often interrupted the T wave of the first one, indicating the R-on-T phenomenon. In two patients there was a gap between the ranges of coupling intervals for single extrasystoles and for the first ones of paired extrasystoles. These observations suggest the presence of longitudinal dissociation in the reentrant pathway as one of the causes of paired ventricular extrasystoles.

The effects of diltiazem hydrochloride on the cardiac conduction: a clinical study of His bundle electrogram

The effects of diltiazem hydrochloride, a new Ca++ antagonistic antianginal drug, on the cardiac conductivity were evaluted in 10 patients with atherosclerotic heart disease. His bundle electrograms were obtained by catheter technique. R-R, A-H and H-V intervals were measured before and after intravenous administration of diltiazem. Diltiazem acted towards significant prolongation in A-H interval. R-R and H-V intervals were insensitive to diltiazem. Diltiazem did not interrupt the cardiac effects of atropine when A-H prolongation was still observed in the subject pretreated with atropine. In short, diltiazem depresses the conductivity of the atrioventricular node selectively and this is not mediated through vagus tone change. This Ca++ antagonist induced A-H prolongation strongly suggests the contribution of Ca++ current on the generation of atrioventricular nodal action potential in humans.

Therapeutic value of mepitiostane in the treatment of advanced breast cancer

A new, orally active antiestrogenic steroid, mepitiostane (20 mg/day), was given to 45 patients with advanced breast cancer. The regression rate was 31.1%, or 14 of 45 patients, and a duration of regression of greater than 6 months was obtained in seven patients. Virilizing effects such as hoarseness, hirsutism, and acne were observed relatively often, but there was no evidence of abnormality in the liver function tests or in the serum calcium level.

Concealed (proximal) Wenckebach phenomenon with distal 2:1 exit block in the ectopic-ventricular junction

The findings in two patients with interpolated ventricular extrasystoles showing 2:1 exit block are reported. In these patients the blocked impulses appear to penetrate into the ectopic-ventricular junction (or reentrant pathway) to a varying extent, and the coexistance of a distal 2:1 exit block and a proximal (concealed) Wenckebach phenomenon in the ectopic-ventricular junction is suggested.

Intracellular recording from pulsating cerebral cortex

An instrument has been developed for recording intracellulary from cortical neurons in an exposed pulsating brain. The electrode moves with the brain pulsations maintaining the electrode within the impaled cell. Stable recordings have been obtained for up to 20 min.

An estimate of the secondary spindle receptor afferent contribution to the stretch reflex in extensor muscles of the decerebrate cat

1. Vibration or stretch of the medial gastrocnemius muscle in the decerebrate cat each caused a significant increase in the tension of a synergist, the lateral gastrocenmius. 2. Simultaneous vibration and stretch of the medial gastrocnemius resulted in a substantial increase of lateral gastrocnemius tension which was greater that that produced by medial gastrocnemius vibration alone. The size of this force increase was proportional to the amplitude of medial gastrocnemius stretch, for the limited range of amplitudes examined. 3. Since the discharge of the medial gastrocnemius I a afferent fibres was held constant by vibration, the additional tension in lateral gastrocnemius provoked by medial gastrocnemius stretch must have resulted from the activation of an excitatory pathway separate from the I a afferent system. The secondary spindle afferent pathway was considered to be the most likely candidate. 4. The contributions of the Ia afferents and the additional stretch induced excitation to the stretch reflex were compared. The Ia potency was calculated from the ration of tonic vibration reflex force and the vibration frequency. The total Ia contribution to the stretch reflex, which was estimated from the product of this ratio and the primary ending stretch sensitivity, seemed modest, and was consistently smaller than the proposed secondary contribution. 5. The medial gastrocnemius nerve was subjected to anodal blockade at a strength sufficient to eliminate Ia transmission. Under these conditions, the lateral gastrocnemius excitation produced by medial gastrocnemius stretch or vibration was largely eliminated. When lateral gastrocnemius vibration was superimposed, the excitatory effect of medial gastrocnemius stretch was partly restored suggesting that some central facilitation by group Ia afferents may be necessary for group II pexcitatory effects to be manifested. 6. Although the additional excitatory actions of medial gastrocnemius stretch were examined exclusively in a synergist, it is suggested that similar effects are likely to occur in the homonymous stretch reflex.

The effect of althesin (CT 1341) on the oxyhaemoglobin dissociation curve in vitro

Blood from non-smoking donors was incubated with Althesin and the PO2 for half-saturation of haemoglobin at standard pH, PCO2 and temperature (P 50) was measured. The mean P 50 values of blood with blood concentrations of Althesin of 0.14 ml/dl and 0.42 ml/dl were greater (1.14 +/- 0.31 (SEM) mm Hg (P less than 0.005) and 2.22 +/- 0.35 (SEM) mm Hg (P less than 0.001), respectively) than that of control blood. These increases were dose-dependent (P less than 0.05). Erythrocyte 2,3-diphosphoglycerate (2,3-DPG) concentrations were not significantly different between the Althesin-treated and the control blood. Although a decrease in the affinity of haemoglobin for oxygen in vitro in the presence of Althesin was statistically significant, this would have no clinical significance if the drug was being used for the induction of anaesthesia only.

Crossed inhibition as revealed by cross-correlogram between bilateral homonymous motor unit spikes in man

Neuromuscular unit (NMU) spikes activated during the tonic vibration reflex (TVR) in man were studied by means of the cross-correlogram test. Those NMUs which preferredly fired at some definite interval with good correlation with vibration were called "locked" spikes. The amount above zero correlation level seen in the cross-correlogram was expressed as ipsilateral "excitatory frequency", Ef. TVR contraction of the ipsilateral quadriceps femoris muscle was stimulated by voluntary contraction of the contralateral quadriceps femoris. I. Cross-correlogram test of the contralateral voluntary NMU spikes with ipsilateral vibration revealed "contralateral inhibitory modulation". Such inhibitory modulation was observed in 24% of the contralateral NMUs during voluntary tracking contraction with visual feed-back and in 22% of NMUs during blind simulated contraction without visual feed-back. The "subtracted" amount, i.e., contralateral inhibitory modulation, was also expressed as the contralateral "inhibitory frequency", If, which was calculated from the indentations of the cross-correlogram. 2. When varied vibratory frequency was applied to the muscle both Ef and If attained their maximum value around an "optimal frequency" of vibration, i.e., 80-95 HZ. 3. The ratio Ef/If was proposed as the reciprocal co-activation ratio which was fairly independent of the change of vibratory frequency. An average value of Ef/If ratio was calculated at 2.2 +/- 0.9 from 19 experiments.