Variations of the cephalic vein anterior to the clavicle in humans.

BACKGROUND: Clinicians should understand that jugulocephalic vein (JCV) variants may be occasionally found. This study aims to classify JCV variants and obtain their frequency. MATERIALS AND METHODS: We investigated anatomical variants of the cephalic vein in 55 human cadavers during a gross anatomy course at our medical school. RESULTS: The percentage of JCVs that pass through the anterior part of the clavicle and anastomose to the jugular vein as per previous studies and our study was 2-5%. Five cases with anastomosis between the cephalic and external jugular veins that pass through the anterior part of the clavicle were found. The courses were classified into 1A, 1B, 2A, and 2B. Type 1 extends beyond the clavicle and anastomoses with the external jugular vein. Type 2 follows the same course as type 1, but anastomoses with the subclavian vein. Subtype A does not have a branch that anastomoses with the axillary vein, whereas subtype B does. We encountered two cases of type 1A and three of type 1B. CONCLUSIONS: Four anatomical variants of the cephalic vein around the clavicle were identified. Clinicians' knowledge of these variants is expected to decrease possible complications if venous access via the cephalic vein is needed.

Common and separate origins of the left and right inferior phrenic artery with a review of the literature.

In a 94-year-old male cadaver, upon which routine dissection was being conducted, a rare variation was found in the gastrophrenic trunk (GPT), the common trunk of the left gastric artery (LGA), right inferior phrenic artery (RIPA), and left inferior phrenic artery (LIPA); the GPT arises from the abdominal aorta. A hepatosplenic trunk accompanied the variation. In this variation, the RIPA first branched from the GPT and then to the LIPA and LGA. Variations in the common trunk of the LIPA and RIPA in the GPT are common, but to our knowledge, a variation (separate inferior phrenic artery in the GPT) similar to our findings has not been previously reported. We discuss the incidence and developmental and clinical significance of this variation with a detailed review of the literature. Knowledge of such a case has important clinical significance for invasive and non-invasive arterial procedures. Therefore, different variations concerning the LGA and inferior phrenic artery should be considered during surgical and non-surgical evaluations.

Anomalous connection of the left posterior renal vein with the left ascending lumbar vein in a Japanese cadaver.

A rare variation was found in one of the two left renal veins in a 94-year-old male cadaver undergoing routine dissection. The characteristic findings in the cadaver included, in addition to the primary left renal vein, the presence of a posterior left renal vein draining to the left ascending lumbar vein without communicating with the inferior vena cava and other renal veins. Variations in the number and arrangement of the vessels terminating in the renal veins are common, but to our knowledge, variation similar to our findings has not been previously reported. This variation may represent an immature form of the complicated development of the renal vessels.

Chronological changes of delayed-type hypersensitivity in mice immunised with testicular germ cells alone.

Experimental autoimmune orchitis (EAO), comprising a breakdown of the testicular immune privilege, is one of the models of immunological male infertility. EAO is characterised by CD4 + T-cell-dependent lymphocytic inflammation and augmented delayed-type hypersensitivity (DTH) against testicular antigens. We previously established an EAO model in mice by immunisation with viable syngeneic testicular germ cells (TGC) alone. However, the sequential change of DTH during development of this EAO has not been analysed yet. In this study, the DTH response during TGC-induced EAO was investigated by the injection of syngeneic TGC protein into the ears of mice. The results showed that a significant DTH response was observed on injection of 20 µg TGC protein, but not on that of 0.2 or 2 µg TGC protein. Also, the level of the DTH response to 20 µg TGC protein was highly relevant to the pathology of EAO development. These results indicate that the DTH response on injection of 20 µg TGC protein into the ears of mice is effective for predicting the pathology of EAO development.

Congenital venous anomalies associated with retrocaval ureter: evaluation using computed tomography.

BACKGROUND: Retrocaval ureter is a rare congenital anomaly resulting from anomalous development of inferior vena cava (IVC) and not from anomalous of the ureter. The anomaly always occurs on the right side due to regression of right supracardinal vein and persistence of right posterior cardinal vein. Retrocaval ureter tends to be associated with various vena cava anomalies because of the embryogenesis. We aimed to identify the prevalence of associated congenital venous anomalies (CVA) resulting from cardinal vein development in adults with retrocaval ureter using computed tomography (CT) images. MATERIALS AND METHODS: The study included 22 adults with retrocaval ureter. We evaluated CT findings and determined the incidence of associated CVA using thin slice data sets from CT scanner with 64 or more detectors. We compared the prevalence of CVA in the retrocaval ureter group (mean age: 57 ± 19 years) and in the control group of 6189 adults with normal ureter (mean age: 66 ± 14 years). RESULTS: In the retrocaval ureter group, 4 (18.2%) adults had CVA including double IVC, right double IVC, preisthmic IVC with horseshoe kidney, and preaortic iliac confluence. One of 2 adults with preaortic iliac confluence had right double right IVC. In the control group, 49 (0.79%) adults had CVA including 37 double IVC, 11 left IVC, and 1 IVC interruption azygos continuation. Fifteen horseshow kidneys were found. The prevalence of associated CVA in the retrocaval ureter group was higher than that in the control group (p < 0.001). CONCLUSIONS: Retrocaval ureter is frequently associated with CVA. Various CVA with retrocaval ureter could happen because of abnormal development of not only the right posterior or supra cardinal vein but also other cardinal veins.

A gross anatomical study of the styloid process of the temporal bone in Japanese cadavers.

BACKGROUND: The incidence of an elongated styloid process (SP) and average length and diameter of SP have not been reported using Japanese cadavers. Data on the female-to-male ratio of an elongated SP vary. We calculated the average length and diameter of SP in Japanese cadavers and compared SP lengths between sexes. MATERIALS AND METHODS: Twenty-seven sides (right and left of bodies) in males and 51 sides in females were analysed. Measurements were obtained from the inferior external acoustic meatus to the distal tip of the SP. SP diameters at the proximal base, midpoint, and distal tip were measured. SP > 30 mm was considered elongated. We used Welch's t-test for the statistical analysis. Fisher's exact two-tailed test was also performed to analyse the female-to-male elongation ratio. A p-value < 0.05 was considered statistically significant. RESULTS: Styloid process elongation prevalence was 29.5% in our sample. The average full length was 27.04 ± 7.88 mm overall; the average diameters were 5.41 ± 1.77 mm at the proximal base and 2.21 ± 1.22 mm at the distal tip. The average SP measurement was 26.81 ± 5.92 mm in males and 27.16 ± 8.79 mm in females (p = 0.74). The female-to-male ratio of SP elongation was 1:2 (p = 0.041). Females had longer full lengths of non-elongated SPs than males (p = 0.004). Males had wider diameters at the proximal base of elongated SPs than females (p = 0.017). CONCLUSIONS: The average length of SP was 27.04 mm in the Japanese population and about 30% of the Japanese presented SP ≥ 30 mm. Male had significantly higher rate than female among the SP ≥ 30 mm, and female had significantly longer SPs than male among the SP < 30 mm. Anatomically, the SP gets narrow as distally goes. Our anatomical findings would be beneficial to creating treatment plans, diagnosis, and surgery.

Variations in the gonadal artery with a single common trunk: embryological hypotheses by observation.

BACKGROUND: A gonadal artery originates as a branch of the abdominal aorta and renal artery inferior to the level of origin of the renal arteries. Variations in multiple right testicular arteries (RTAs) arising from the abdominal aorta are common. We aimed to re-evaluate the unusual courses of gonadal arteries with a single common trunk in relation to the inferior vena cava and left renal vein and explain the developmental anatomy. MATERIALS AND METHODS: The observational cross-sectional study was performed on 54 Japanese adult cadavers (29 men and 25 women). We examined the literature and developed embryological hypotheses on the single common trunk of the gonadal artery. RESULTS: The gonadal artery, testicular artery, and ovarian artery arose from the abdominal aorta in 93.1%, 96.3%, and 89.6% of cases, respectively, and from the renal artery in 4.9%, 3.7%, and 6.3% of cases, respectively. We found two rare variations in the RTAs observed during the routine dissection of two male cadavers; in these two cases, a single common trunk of the RTAs originated from the abdominal aorta. A single common trunk was found in 3.7% of cadavers, 2.0% of sides, and 2.0% of arteries in the gonadal artery and in 6.9% of cadavers, 3.8% of sides, and 3.7% of arteries in the testicular artery. All cases of the single common trunk, including those in past reports, were observed only in men. CONCLUSIONS: Knowledge of the variations in RTAs has important clinical consequences for invasive and non-invasive arterial procedures. In addition, this variation provides a new interpretation of the embryology of the gonadal artery. Variations similar to our findings have not been previously reported. Therefore, different variations concerning the RTA should be considered during surgical and non-surgical evaluations.

Ca2+ binding sites in plasma membranes of rat liver and hepatoma cells, and effect of concanavalin A on the Ca2+ binding sites and cellular uptake of Ca2+.

1. Plasma membranes isolated from rat livers and ascites hepatoma cells (AH-130, AH-7974) were assayed for specific Ca2+ binding sites using 45Ca2+ and a Millipore filtration technique. The presence of higher (Kd = 1.4--1.5 . 10(-5) M) and lower (Kd = 0.9--1.0 . 10(-4) M) affinity sites in both liver and hepatoma membranes was observed. The hepatoma plasma membranes however, showed 1.4--2.1-fold as many Ca2+ binding sites (higher and lower affinity sites) as the liver plasma membranes on the basis of protein. 2. Concanavalin A stimulated the specific Ca2+ binding to liver and hepatoma plasma membranes, showing a maximal stimulation (3--5-fold) at 100 microgram/ml. Succinyl concanavalin A was less effective, whereas wheat germ agglutinin and ricinus lectin were ineffective. 3. Concanavalin A stimulated the Ca2+ uptake by AH-7974 cells. The concanavalin A-mediated stimulation of Ca2+ uptake showed lectin-concentrations and Ca2+-concentration dependencies similar to those in the concanavalin A-mediated stimulation of Ca2+ binding.

Cell surface proteoglycans as a negative modulator in concanavalin A-mediated agglutination of hepatoma cells.

Proteoglycan (heparan sulfate-protein conjugate) was solubilized with 8 M urea from rat liver plasma membranes after enzymic (RNAase, neuraminidase) treatments and extensively purified by chromatography and gel filtration. The final products gave an average ratio of hexuronate to protein (weight) of approx. 1.5, contained hexosamine equimolar to hexuronate and were sensitive to beta-elimination (the molecular weight being reduced from 20 . 10(4) to 3 . 10(4) (gel filtration)). The proteoglycan fraction, when added to trypsinized and untrypsinized ascites hepatoma (AH-130F(N)) cells, inhibited the concanavalin A-mediated agglutination of the cells. However, the alkali-treated proteoglycan (beta-elimination) or acid mucopolysaccharide fraction prepared from liver plasma membranes by papain digestion were less effective, and a reference preparation of heparan sulfate was almost ineffective. It was confirmed that significant amounts of proteoglycan labelled with 35SO4(2-) were firmly bound to or taken up by the trypsinized ascites hepatoma cells. These results together with the sensitization of lectin-mediated agglutination by mild protease treatment of cells suggest that cell surface proteoglycans may act as a negative modulator in the lectin-mediated agglutination of cells.

Isolation and identification of glycosaminoglycans associated with purified nuclei from rat liver.

Nuclei isolated from rat liver were purified extensively and then subjected to extraction of glycosaminoglycans by the conventional method with a slight modification including the treatments with amylase, nucleases (DNAase and RNAase), and sialidase in addition to the pronase treatment. The nuclear glycosaminoglycan fraction thus prepared was subjected to chromatography on Dowes 1-X2 (Cl-) and electrophoresis before or after digestion with specific enzymes such as Streptomyces hyaluronidase, chondroitinase ABC and AC. These results together with the results of chemical analyses have revealed that the purified nuclei from rat liver contain glycosaminoglycans equivalent to 0.2-0.3 microgram hexuronic acid per mg DNA. A major component of the nuclear glycosaminoglycans has been identified as hyaluronic acid, while a minor component as chondroitin sulfate A (OR C). Preliminary investigations have shown that most of the nuclear glycosaminoglycans are associated with the chromatin fraction.

Estrogen-dependent and progesterone-arrested synthesis and secretion of sulfated glycoproteins in luminal epithelia of rat uteri.

1. 35SO4 administered intraperitoneally was specifically incorporated into a glycopeptide component separated by electrophoresis of the glycosaminoglycan fraction prepared from the uterine epithelia (luminal), as well as the uterine fluid of ovariectomized rats treated with estradiol-17 beta, in contrast to the rats without estrogen treatment. 2. The epithelial cells of uteri isolated from estrogen-treated ovariectomized rats incorporated 35SO4 in vitro into at least two macromolecular components. The larger molecular weight component (sodium dodecyl sulfate polyacryl-amide gel electrophoresis and/or gel filtration) labelled with 35S was observed in both the cytosol and particulate fractions, whereas the smaller molecular weight component labelled with 35S was found only in the particulate fraction. 35SO4 was also incorporated into two macromolecular components in the incubation medium, similarly to the particulate fraction. A 35 SO4-labelled glycopeptide similar to that from the epithelial particulate fraction and the incubation medium, and not from the epithelial cytosol fraction. 3. Progesterone, in contrast to estrogen, did not stimulate the sulfated blycoprotein synthesis. Moreover, progesterone administered together with or after estrogen-administration completely arrested the estrogen-dependent synthesis and secretion of the sulfated glycoproteins in the uterine epithelia.

Pattern of glycosaminoglycans and glycoproteins associated with nuclei of regenerating liver of rat.

1. Hyaluronic acid was detected as the largest glycosaminoglycan component in the glycosaminoglycan fraction from purified nuclei of regenerating livers as in the case of normal livers (Furukawa, K. and Tarayama, H. (1977) Biochim. Biophys. Acta 499, 278--289). However, the nuclear content of glycosaminoglycans tended to decrease after partial hepatectomy, reaching one-third of the normal liver level at 24--30 h after partial hepatectomy. On the other hand, two new polyanionic components were detected in the glycosaminoglycan fraction from regenerating liver nuclei. 2. One of these new components seems to be a sulfated glycopeptide. The 35SO4 incorporation into this component was stimulated biphasically after partial hepatectomy; the first stimulation occurring immediately after partial hepatectomy and the second stimulation occurring almost in parallel to the DNA synthesis. 3. Another polyacnionic component which also increases in the nuclear content after partial hepatectomy lacks hexuronic acid, sialic acid and 35SO4 and yet it is intensely stained by Alcian Blue. Preliminary investigations revealed the presence of hexose, ribose and phosphate as the major components. 4. In contrast to the primary localization of hyaluronic acid in the chromatin fraction and also in the nonhistone chromosomal protein fraction from it, these new polyanionic components were detected mainly in the karyosol fraction.

Comparison of the epinephrine-mediated activation of adenylate cyclase in plasma membranes from liver and ascites hepatomas of rats.

(1) The apparent [3H]epinephrine binding parameters of plasma membranes from rat liver and ascites hepatomas such as AH-7974, AH-371A and AH-130, as measured by equilibrium dialysis and/or Millipore filtration, were almost similar to each other. The epinephrine binding sites in the plasma membranes were heterogenous (alpha, beta-receptors and non specific sites), but the pattern of these binding sites in the liver membranes appeared almost similar to that in the hepatoma membranes. 2. The beta-receptor seemed to be specifically involved in the epinephrine-mediated activation of adenylate cyclase of the liver membranes. In spite of the presence of almost similar beta-receptors and adenylate cyclase, the adenylate cyclase of hepatoma membranes was found to be less sensitive to the epinephrine-mediated activation. 3. GTP alone was found to activate adenylate cyclase of liver and hepatoma membranes to some extents when the concentration of ATP was lower (0.3 mM). When GTP was added with epinephrine, a marked, synergistic activation of adenylate cyclase was observed in liver plasma membranes, but not in hepatoma ones. 4. The synergistic activation of adenylate cyclase by epinephrine plus GTP showed a characteristic kinetic feature, reaching a maximal peak within 1 min or so after mixing. 5. Binding of [3H]epinephrine to liver membranes proceeded monophasically in the absence of GTP, while it proceeded biphasically in the presence of GTP, showing the retardation of binding at some earlier stages. GTP added at the time of binding equilibrium induced the temporary release of bound epinephrine from the beta-receptors. The GTP-induced temporary release of bound epinephrine, occurring within 4-5 min after the addition of GTP, was less marked in the hepatoma membranes as compared with the liver membranes. 6. Possible impairment of the GTP-dependent coupling mechanism in the receptor-adenylate cyclase system of hepatoma plasma membranes was suggested.

Effects of deoxyribonuclease I and micrococcal nuclease on the release of dexamethasone-receptor complex from nuclei of sensitive and insensitive hepatoma cell lines.

(1) Fu5 cells were sensitive to the glucocorticoid inhibition of cell growth and the hormonal induction of tyrosine aminotransferase (but not fructose-1,6-bisphosphatase and glycogen synthase). AH-130 and AH-7974 cells were insensitive to both effects. (2) The release of [3H]dexamethasone radioactivity from the nuclei of Fu5 and AH-130 cells preincubated with [3H]dexamethasone increased as the KCl concentration increased from 0 to 0.4 M, with no significant difference between the two cell lines. (3) The radioactivity was more sensitively released in Fu5 nuclei than in AH-130 nuclei upon treatment with DNAase I. The release of radioactivity was always larger than the release of DNA in both cell nuclei. In contrast to DNAase I, micrococcal nuclease treatment did not show any difference between the two cell lines in the release of radioactivity from nuclei, always showing a release of radioactivity equal to that of DNA.

Dynamics of calmodulin and cyclic AMP phosphodiesterase in plasma membranes of rat livers and ascites hepatomas.

1. Plasma membranes from ascites hepatoma cells (AH-7974, AH-130) contained much smaller amounts of calmodulin (about half) and cyclic AMP phosphodiesterase (about one-third) compared to plasma membranes of rat livers. 2. Some of calmodulin molecules in liver plasma membranes were released by repeated washing. The 'washed' liver plasma membranes showed the presence of specific binding sites for externally added calmodulin molecules (bovine brain) (N = 140 pmol/mg protein, Kd = 7.9 . 10(-8) M). The calmodulin content of AH-7974 plasma membranes was not reduced by repeated washing. The binding of calmodulin to the 'washed' AH-7974 plasma membranes was only of nonspecific nature with negative cooperativity. 3. Plasma membranes (liver and AH-7974) appeared to contain both calmodulin-dependent and calmodulin-independent phosphodiesterase, but the stimulation by externally added Ca2+ plus calmodulin was rather small. Externally added calmodulin-dependent phosphodiesterase (bovine brain) was bound more to 'washed' liver plasma membranes than to 'washed' AH-7974 plasma membranes. Newly bound phosphodiesterase appeared to be more sensitive to the stimulation by Ca2+ plus calmodulin in 'washed' hepatoma plasma membranes than in 'washed' liver plasma membranes. 4. Preincubation of 'washed' plasma membranes (liver and hepatoma) with calmodulin did not affect the binding of phosphodiesterase, but the sensitivity of phosphodiesterase to the stimulation by Ca2+ plus calmodulin in hepatoma plasma membranes was lost.

Liver plasma membranes and proteoglycan prepared therefrom inhibit the growth of hepatoma cells in vitro.

1. Plasma membranes from rat liver or kidney inhibited the growth of hepatoma (AH-130) cells in vitro. AH-130 plasma membranes or erythrocyte ghosts inhibited the growth of AH-130 cells less effectively. The inhibitory activity of liver plasma membranes was lost by heat treatment, or mild protease (papain or bromelin, but not trypsin or pronase) treatment, whereas it was retained after sialidase treatment of delipidation by ethanol/ether. 2. Proteoglycan (proteoheparan sulfate) prepared from liver plasma membranes inhibited the growth of AH-130 cells, but heparan sulfate was less active. The inhibitory activity of liver plasma membranes seemed, however, not to be ascribable solely to proteoheparan sulfate associated with plasma membranes. 3. Preliminary investigation suggested that the molecular weight 40 000 component may be a major inhibitory principle in liver plasma membranes.

Hormonal effect on glycosaminoglycans and glycoproteins in uteri of ovariectomized rats.

1. Glycosaminoglycans such as chondroitin sulfate A (or C), chondroitin sulfate B (dermatan sulfate), heparitin sulfate (heparan sulfate) and hyaluronic acid were identified as major glycosaminoglycan components in whole uteri as well as in uterine stroma of rats. Two types of sialoglycoproteins with different electrophoretic mobilities (fast- and slow-migrating) were detected in the glycosaminoglycan fraction from the luminal epithelia. 2. Treatment of ovariectomized rats with estradiol-17beta markedly increased the uterine contents of glycosaminoglycans. Chondroitin sulfate A (or C) was found to increase more than chondroitin sulfate B. Furthermore, it was found that the estrogen treatment specifically increases the fast-migrating sialoglycoprotein level in the luminal epithelia and results in the appearance of it in the uterine fluid. 3. Administration of progesterone to ovariectomized rats slightly increased the uterine glycosaminoglycan content without appreciable alteration of the uterine glycosaminoglycan pattern.

Prostaglandin receptor-adenylate cyclase system in plasma membranes of rat liver and ascites hepatomas, and the effect of GTP upon it.

1. Adenylate cyclase in plasma membranes from rat liver was stimulated by prostaglandin E1, and to a lesser extent by prostaglandin E2. Prostaglandin F1alpha and A1 did not stimulate the cyclase. The prostaglandin E1-mediated activation was found to require GTP when the substrate ATP concentration was reduced from 3 mM to 0.3 mM in the reaction mixture. Adenylate cyclase of the plasma membranes from rat ascites hepatomas AH-130 and AH-7974 was not stimulated by prostaglandin E1 in the presence or the absence of GTP, although the basal activity of adenylate cyclase as well as its stimulation by GTP alone were similar to normal liver plasma membranes. 2. Liver plasma membranes were found to have two specific binders for [3H] prostaglandin E1 with dissociation constants of 17.6-10(-9) M and 13.6-10(8) M (37 degrees C) and one specific binder for [3H]prostaglandin F2alpha with a dissociation constant of 2.31-10(8) M (37 degrees C). The specific binders for prostaglandin E1 could not be detected in the hepatoma plasma membranes. 3. Binding of [3H] prostaglandin E1 to the liver plasma membranes was exchange by, GTP dGPT, GDP, ATP and GMP-P(N)P, but not by GMP, CGMP, DTTP, UTP or CTP. The increase in the binding of [3H] prostaglandin E1 was found to be due to the increased affinity of the specific binders to prostaglandin F2alpha was not affected by GTP. 4. GTP alone was found to increase V of adenylate cyclase of liver plasma membranes, while GTP plus prostaglandin E1 was found to decrease Km of adenylate cyclase in addition to the increase of V to a further extent.

Change of coupling system of receptor-adenylate cyclase induced by epinephrine and GTP in plasma membranes of rat liver.

1. The binding of [3H]epinephrine to plasma membranes was affected (temporary release of bound epinephrine and characteristic retardation of epinephrine binding) not only by GTP but also by dGTP and guanylylimidodiphosphate, whereas the binding of [3H]dihydroalprenolol was not affected by GTP. GTP affected the binding of [3H]epinephrine in the presence of alpha-antagonists, but not in the presence of beta-antagonists, suggesting that the GTP effects are specific to beta-agonists and beta-receptors. 2. The half-maximal release of bound [3H]epinephrine was found at 8.8 . 10(-6) M GTP in the absence of ATP, whereas it was found at 1.6 . 10(-6) M GTP in the presence of 0.3 mM ATP in coincidence with the half-maximal activation of adenylate cyclase by GTP in the presence of 0.3 mM ATP (as measured at 30 s of incubation). 3. In the presence of 4 . 10(-5) M GTP, adenylate cyclase activity as measured at 30 s of incubation (State I) tended to increase with epinephrine concentration, showing no saturation tendency even at 1 . 10(-4) M epinephrine. The activity of State II, which is established at 4 min of incubation, was much lower than that of State I but was found to reach a plateau as the epinephrine concentration increased, showing half-maximal activation at an epinephrine concentration between 2 . 10(-6) and 2 . 10(-7) M. 4. Apparent kinetic parameters (Km and V) for State I as assayed at 30 s of incubation suggested that GTP alone may increase V slightly, whereas epinephrine plus GTP may increase the V to a further extent and simultaneously decrease the Km. 5. Adenylate cyclase of plasma membranes pretreated with epinephrine plus GTP was stimulated by GTP alone similarly to untreated membranes, but it was no longer responsive to the synergistic activation by epinephrine plus GTP. Accordingly, the binding of [3H]epinephrine to the pretreated plasma membranes was no longer affected by GTP. 6. The results of the present study seem to support the idea that the most active and coherently coupling state (State I) of the beta-receptor-adenylate cyclase system generated in the presence of epinephrine plus GTP is very labile and degenerates before reaching equilibrium. In turn, State II, in which the coherently coupling mechanism is largely impaired, seems to be established in due time. The characteristic biphasic kinetics of [3H]epinephrine binding in the presence of GTP seem to be related to the above change occurring in the beta-receptor-adenylate cyclase system.

Arginase as an inhibitory principle in liver plasma membranes arresting the growth of various mammalian cells in vitro.

Plasma membranes prepared from rat livers inhibited the in vitro growth of various mammalian cells including hepatoma cells in a concentration-dependent manner, showing almost complete arrest of cell growth at 0.1 mg protein/ml. Some of these cells tested, i.e., leukemia (L1210 and P388) and myeloma (P3-NS-1/1-Ag4-1) cells, were labile in the presence of plasma membranes (losing the viability), and CHO (Chinese hamster ovary) cells became round without detaching from the substratum. The culture medium preincubated with liver plasma membranes no longer supported the growth of hepatoma cells (AHI3 and AH66F). However, the 'conditioned' medium supplemented with L-arginine, supported the growth of the cells. Moreover, the addition of L-ornithine to the cultures containing plasma membranes markedly reduced the inhibitory effect of plasma membranes. The plasma membrane preparations were found to possess considerable arginase activity. There results seem to indicate the possible involvement of arginase in the inhibition of cell growth by liver plasma membranes.