Determination of beta-adrenoceptor subtype on rat isolated ventricular myocytes by use of highly selective beta-antagonists.

1. The relative proportions of beta 1- and beta 2-adrenoceptors were determined by radioligand binding studies in three different rat myocardial preparations: membranes prepared from rat ventricle (ventricular membranes), membranes prepared from rat isolated ventricular myocytes (myocyte membranes), and myocytes isolated from rat ventricle (myocytes). 2. Competition experiments using CGP 20712A or ICI 118,551 with [125I]-iodocyanopindolol ([125I]-ICYP) revealed high- and low-affinity binding sites in ventricular membranes. The concentration at which each beta-antagonist occupied 100% of its high-affinity binding sites was 300 nM for CGP 20712A (beta 1-adrenoceptor) and 50 nM for ICI 118,551 (beta 2-adrenoceptor). 3. The density of high-affinity (beta 1-adrenoceptor) and low-affinity (beta 2-adrenoceptor) binding sites for CGP 20712A was measured by a saturation experiment using [125I]-ICYP in the presence and absence of 300 nM CGP 20712A. In ventricular membranes, the proportions of high-affinity and low-affinity binding sites for CGP 20712A were 73% and 27%, respectively, whereas in myocyte membranes, the corresponding figures were 90% and 10%, respectively. The density of low-affinity binding sites for CGP 20712A in ventricular membranes, defined as [125I]-ICYP-specific binding in the presence of 300 nM CGP 20712A, was decreased by addition of 50 nM ICI 118,551, whereas that in myocyte membranes was not affected. 4. In myocytes, specific binding of [125I]-ICYP and [3H]-CGP 12177 was not detected by saturation experiments performed in the presence of 300 nM CGP 20712A.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rupture of flexor tendons due to pisotriquetral osteoarthritis

We are reporting a case of a flexor profundus tendon rupture of the little finger due to pisotriquetral osteoarthrosis. Resection of the pisiform bone and resurfacing of the carpal tunnel with the joint capsule was performed for the osteoarthrosis and free tendon grafting for the tendon rupture. The tendon grafting and a subsquent tenolysis restored the function of the little finger. Other than radiological changes in the pisotriquetral joint, the diagnostic value of preoperative radiocarpal arthrography was emphasized in this rare complication of pisotriquetral arthrosis.     

Phorbol ester, not growth hormone releasing factor, consistently stimulates growth hormone release from somatotroph adenomas in culture

In order to study the mechanism of GH secretion from somatotroph adenoma cells, we have compared the effect of 12–O-tetradecanoyl phorboi-13-acetate (TPA) with that of growth hormone releasing factor (GRF) on GH secretion from human somatotroph adenoma cells cultured in monolayer. Pituitary adenoma cells were obtained from 13 patients with acromegaly undergoing surgery. On the 7th day of culture, the cells were exposed for 2 h to secretagogues. All 13 adenoma cell cultures (100%) responded to TPA (1·6–16·0 nmol/I) with a two- to six-fold increase in GH release (240·37% Increase of control: mean±SE). The response was detectable within 10 min, and was maximal at 2 h. Phosphollpase C (7·7 mmol/I) also stimulated a two-to ten-fold Increase In GH release in all four adenomas examined (100%). GH release was stimulated by GRF (2·0 nmol/I) in eight out of 12 adenoma cells (67%), but the magnitude of the responses to GRF (60·18% Increase of control: mean ± SE) were much smaller than that of TPA. Five out of 13 adenomas secreted detectable amount of PRL Into the medium and these five adenomas (100%) responded to TPA (16·0 nmol/I) with a two- to six-fold Increase. These observations indicate that the activation of protein kinase C is the consistent stimulator in GH and PRL secretion In human somatotroph adenoma cells. However, It is not determined whether the protein kinase C     

Clonal growth of hepatitis B virus-integrated hepatocytes in cirrhotic liver nodules.

A total of 83 cirrhotic nodules (pseudolobules) individually collected from 11 cirrhotic livers of hepatitis B virus carrier patient were analyzed for the frequency and mode of hepatitis B virus integration as well as histological features. Southern blot analysis disclosed discrete bands at higher molecular weight region in 26 of 83 nodules (31.3%), indicating a clonal growth of hepatocytes with viral integration. Considerable variation (0-75%) existed in the positive rates for discrete bands in nodules among livers. Molecular cloning revealed the sequence flanking an integrated viral sequence to be host DNA and thus confirmed true integration. Histological analysis, however, did not reveal any neoplastic-appearing foci of growth within nodules, despite the fact that the detection sensitivity would predict clones of more than 10(5) cells to give rise to clonal integration patterns on Southern blot analysis. The question of whether clonal expansion of hepatocytes reflects any viral integration-associated growth advantage and/or a preneoplastic condition awaits future studies.     

Rupture of the flexor tendon after malunited Colles' fracture.

Flexor tendon rupture as a complication of Colles' fracture is rare. We describe a case of attrition rupture of flexor tendons to the ring and little fingers after a malunited Colles' fracture, and we review the 17 previously reported cases.     

Correlation between inflammatory cellular responses and chemotactic activity in bronchoalveolar lavage fluid following intratracheal instillation of nickel sulfate in rats

In a preceding study, we reported that the numbers of macrophages and polymorphonuclear leukocytes (PMN) were increased in bronchoalveolar lavage fluid (BALF) following the intratracheal instillation of nickel sulfate (NiSO₄) in rats. In the present study, BALF chemotactic activities for both macrophages and PMN were measured to investigate if the increases of these inflammatory cells in BALF depend on increases in chemotactic activities in epithelial lining fluid (ELF) of the lung. Both the number of PMN and the PMN chemotactic activity peaked at 2 days post-instillation and they were significantly correlated. However, the PMN chemotactic activity was inversely correlated with concentration of leukotriene B₄ (LTB₄), a well-known chemotaxin. Although PMN were not observed in control BALF, LTB₄ concentration in the control ELF (ca. 5×10^–7 M) was estimated to have a potential to attract PMN chemotactically through a membrane in in vitro migration assay. These results suggest that the presence of LTB₄ in ELF itself does not trigger transpulmonary PMN infiltration. The rat BALF were fractionated by high performance liquid chromatography (HPLC), and PMN chemotactic activity of each fraction was measured. The elution profiles of PMN chemotactic activity showed that there were at least two different chemotaxins in BALF obtained from the NiSO₄-exposed rats. Macrophage chemotactic activity in BALF also peaked at 2 days post-instillation. However, the number of macrophages was not significantly correlated with the chemotactic activity for macrophage in BALF. The HPLC study showed that the macrophage chemotactic substance in the BALF obtained from NiSO₄-exposed rats was different from complement fragment (C5a) and its MW was estimated to be 10 – 12 kD. Received: 1 December 1993/Accepted: 16 March 1994     

Aortic arch replacement with proximal first technique.

BACKGROUND: Deep hypothermic circulatory arrest (DHCA) without retrograde cerebral perfusion (RCP) has a strict time limit. We modified a surgical technique for anastomosis to shorten the period of DHCA and unilateral cerebral perfusion (UCP). METHODS: Between March 1993 and August 2001, retrospective analysis was done on 23 consecutive patients, who underwent aortic arch replacement with branches. The patients were divided into two groups: DHCA group and UCP group. The DHCA group, in which DHCA alone and without additional cerebral perfusion was performed, comprised of nine patients. Proximal aortic anastomosis was performed first during systemic cooling; then both the brachiocephalic artery and left carotid artery were reconstructed with the branches of the artificial graft during circulatory arrest; thereafter, cerebral and coronary perfusions were resumed. The UCP group, in which DHCA was not used but right hemisphere perfusion during deep hypothermia was performed when the origin of brachiocephalic artery was safely clamped, consisted of 14 patients. RESULTS: Mean time of DHCA was 18.8+/-4.2 minutes and that of right hemisphere perfusion time was 11.0+/-3.8 minutes, respectively. Twenty-one patients survived the surgery (91.3%), and two (8.7%) died during hospitalization. Transient cerebral complication occurred in four patients in the DHCA group and all recovered. Logistic regression analysis revealed that DHCA was the only parameter to significantly influence temporary neurological dysfunction. There was no other significant difference between the two groups. CONCLUSION: With our modified and simple surgical technique for aortic arch repair, we were able to successfully shorten the DHCA time and right hemisphere perfusion time. However, because DHCA was the only parameter to significantly influence temporary neurological dysfunction, some form of continuous cerebral perfusion at deep hypothermia may be a safer method to preserve cerebral function.     

FIBER TYPE DIFFERENTIATION AND MYOSIN EXPRESSION IN REGENERATING RAT MUSCLES

The relation between fiber type differentiation and the expression of slow and fast myosin isoforms was examined in regenerating rat muscles after injection of a myotoxic agent, bupivacaine. The histochemical myosin ATPase reaction for fiber typing demonstrated that immature type 2C fibers differentiated into type 1, 2A and 2B fibers. Slow and fast myosin isoforms were demonstrated immunohistochemically using antibodies raised against myosins extracted from the slow-twitch soleus and fast-twitch tensor fasciae latae muscles of mature guinea pigs (anti-SOL, anti-TFL). The results showed that immature type 2C fibers destined to differentiate into type 1 fibers first reacted with anti-TFL only, and later reacted with both anti-TFL and anti-SOL, whereas those destined to differentiate into type 2A and 2B fibers reacted with anti-TFL only throughout regeneration. The significance of the myosin isoforms that react with anti-TFL in immature type 2C fibers was discussed. ACTA PATHOL. JPN. 37: 1537-1547, 1987.