Performance of a modified three-level classification in stratifying open liver resection procedures in terms of complexity and postoperative morbidity

BACKGROUND

Traditional classifications for open liver resection are not always associated with surgical complexity and postoperative morbidity. The aim of this study was to test whether a three-level classification for stratifying surgical complexity based on surgical and postoperative outcomes, originally devised for laparoscopic liver resection, is superior to classifications based on a previously reported survey for stratifying surgical complexity of open liver resections, minor/major nomenclature or number of resected segments.

METHODS

Patients undergoing a first open liver resection without simultaneous procedures at MD Anderson Cancer Center (Houston cohort) or the University of Tokyo (Tokyo cohort) were studied. Surgical and postoperative outcomes were compared among three grades: I (wedge resection for anterolateral or posterosuperior segment and left lateral sectionectomy); II (anterolateral segmentectomy and left hepatectomy); III (posterosuperior segmentectomy, right posterior sectionectomy, right hepatectomy, central hepatectomy and extended left/right hepatectomy).

RESULTS

In both the Houston (1878 patients) and Tokyo (1202) cohorts, duration of operation, estimated blood loss and comprehensive complication index score differed between the three grades (all P < 0·050) and increased in stepwise fashion from grades I to III (all P < 0·001). Left hepatectomy was associated with better surgical and postoperative outcomes than right hepatectomy, extended right hepatectomy and right posterior sectionectomy, although these four procedures were categorized as being of medium complexity in the survey-based classification. Surgical outcomes of minor open liver resections also differed between the three grades (all P < 0·050). For duration of operation and blood loss, the area under the curve was higher for the three-level classification than for the minor/major or segment-based classification.

CONCLUSION

The three-level classification may be useful in studies analysing open liver resection at Western and Eastern centres.

Hepatectomy for hepatocellular carcinoma after perioperative management of portal hypertension

Background

Indications for hepatectomy in patients with hepatocellular carcinoma (HCC) who have portal hypertension (PH) have been controversial. Some studies have concluded that PH is a contraindication to hepatectomy, whereas others have suggested that perioperative prophylactic management (PPM) can help overcome complications after hepatectomy associated with PH. The objective of this retrospective study was to assess the short- and long-term outcomes after hepatectomy for HCC in patients with PH, with or without PPM.

Methods

Records were reviewed of consecutive patients who underwent hepatectomy for HCC, with or without PPM of PH, in a single institution from 1994 to 2015. Patients were divided into three groups: those who received PPM for PH (PPM group), patients who had PH but did not receive PPM (no-PPM group) and those without PH (no-PH group).

Results

A total of 1259 patients were enrolled, including 123 in the PPM group, 181 in the no-PPM group and 955 in the no-PH group. Three- and 5-year overall survival rates were 74·3 and 53·1 per cent respectively in the PPM group, 69·2 and 54·9 per cent in the no-PPM group, and 78·1 and 64·2 per cent in the no-PH group (P = 0·520 for PPM versus no PPM, P = 0·027 for PPM versus no PH, and P &lt; 0·001 for no PPM versus no PH). Postoperative morbidity and mortality rates were 26·0 and 0·8 per cent respectively in the PPM group, 29·8 and 1·1 per cent in the no-PPM group, and 20·3 and 0 per cent in the no-PH group.

Conclusion

The present study has demonstrated acceptable outcomes among patients with HCC who received appropriate management for PH in an Asian population. Enhancement of the safety of hepatic resection through use of PPM may provide a rationale for expansion of indications for hepatectomy in patients with PH.

Use of a Right Lateral Sector Graft in Living Donor Liver Transplantation Is Feasible, but Special Caution Is Needed With Respect to Liver Anatomy

Right lateral sector (RLS) grafting has been introduced to enlarge the potential donor pool for living donor liver transplantation (LDLT); however, evidence of its feasibility is limited. Data from 437 LDLTs carried out between 2000 and 2013 were analyzed retrospectively. LDLTs using a right liver graft (n = 251) were compared with those using a RLS graft (RLSG; n = 28). No donor mortality occurred, and the major complication rates were similar between the two groups. Postoperative liver function preservation was better in the RLSG donors. Concerning the recipients, the mortality and overall survival rates were similar between the two groups. The complication rate for the recipients was higher when more than two arterial or biliary anastomoses were necessary. A systematic literature search identified four reports on LDLT using RLSGs. Among 66 LDLTs, including the present series, there were no cases of donor death, and the rates of major and minor complications in the donors were 6% and 29%, respectively. The major complication and overall mortality rates in the recipients were 29% and 6%, respectively. LDLT using an RLSG is feasible, with an acceptable survival rate among the recipients.

Sinistral portal hypertension after pancreaticoduodenectomy with splenic vein ligation

BACKGROUND

Splenic vein ligation may result in sinistral (left-sided) portal hypertension and gastrointestinal haemorrhage. The aim of this study was to analyse the pathogenesis of sinistral portal hypertension following splenic vein ligation in pancreaticoduodenectomy.

METHODS

Patients who underwent pancreaticoduodenectomy for pancreatic cancer between January 2005 and December 2012 were included in this retrospective study. The venous flow pattern from the spleen and splenic hypertrophy were examined after surgery.

RESULTS

Of 103 patients who underwent pancreaticoduodenectomy with portal vein resection, 43 had splenic vein ligation. There were two predominant venous flow patterns from the spleen. In the varicose route (27 patients), flow from the spleen passed to colonic varices and/or other varicose veins. In the non-varicose route, flow from the spleen passed through a splenocolonic collateral (14 patients) or a spontaneous splenorenal shunt (2 patients). The varicose route was associated with significantly greater splenic hypertrophy than the non-varicose route (median splenic hypertrophy ratio 1·52 versus 0·94; P < 0·001). All patients with the varicose route had colonic varices, and none had a right colic marginal vein at the hepatic flexure.

CONCLUSION

Pancreaticoduodenectomy with splenic vein ligation may lead to sinistral portal hypertension. To avoid the development of varices, it is important to preserve the right colic marginal vein. Reconstruction of the splenic vein should be considered if the right colic marginal vein is divided.

Contrast-enhanced intraoperative ultrasonography using perfluorobutane microbubbles for the enumeration of colorectal liver metastases

BACKGROUND

Intraoperative ultrasonography (IOUS) is considered the standard for the identification of liver metastases. Use of lipid-stabilized perfluorobutane microbubbles as an ultrasound contrast agent may improve this. The value of contrast-enhanced IOUS (CE-IOUS) in enumerating colorectal liver metastases was studied here.

METHODS

CE-IOUS was performed in consecutive resections for colorectal liver metastases in 2007-2010. All patients underwent preoperative computed tomography. Magnetic resonance imaging was not carried out routinely. Conventional intraoperative examination including IOUS, and CE-IOUS with peripherally injected contrast were performed. The histopathological findings and 6-month follow-up images were used as the reference standard.

RESULTS

The study group of 102 patients had a total of 315 lesions identified on preoperative imaging (2·4 lesions per operation; 129 operations). Conventional intraoperative examination including IOUS identified 350 lesions (2·7 per operation). CE-IOUS identified 370 lesions (2·9 per operation). The sensitivity, specificity and accuracy of CE-IOUS were 97·1, 59·1 and 93·2 per cent respectively. The CE-IOUS findings altered the surgical plan in 19 operations (14·7 per cent).

CONCLUSION

CE-IOUS provided additional information to that obtained using contemporary preoperative imaging and conventional intraoperative examinations.

Randomized clinical trial of the effect of a saline-linked radiofrequency coagulator on blood loss during hepatic resection

BACKGROUND

Use of a saline-linked radiofrequency coagulator (dissecting sealer) has been suggested to reduce blood loss during hepatic resection. A randomized clinical trial was conducted to assess the effects of using the device on the amount of blood loss.

METHODS

Patients scheduled to undergo hepatic resection were randomly assigned to either use of the dissecting sealer or the clamp crushing method. The primary outcome measure was blood loss during liver parenchymal division. Multivariate analysis was also performed.

RESULTS

Ninety-four consecutive patients underwent hepatic resection and 40 patients were assigned to each group. There were no significant differences between the dissecting sealer and clamp crushing groups in blood loss during liver parenchymal division (median 373 versus 535 ml; P = 0.252) or total intraoperative blood loss (665 versus 733 ml; P = 0.450). Multivariate analysis revealed that use of the dissecting sealer offered no protection against blood loss compared with the clamp crushing method (odds ratio 1.17 (95 per cent confidence interval 0.39 to 3.53); P = 0.777), whereas number of resections, thoracotomy and type of resection had a significant effect.

CONCLUSION

Use of a dissecting sealer offered no substantial benefit over the clamp crushing method in reducing blood loss during hepatic resection.

Purification and properties of a proteinaceous toxin from the brackishwater clam (Corbicula japonica)

Water extracts from the brackishwater clam (Corbicula japonica) are lethal to mice upon i.v. injection. Further mouse assays confirmed that the toxicity exhibits a regional variation but no seasonal or sexual variations. The C. japonica toxin was purified from foot muscle, the most toxic tissue, successively by hydrophobic chromatography on Phenyl Sepharose, gel filtration on Sephacryl S-200, hydrophobic FPLC on Phenyl Superose and cation-exchange FPLC on Mono S. The purified toxin had an i.v. LD50 of 11 microg/kg against mice. It was a weakly basic protein (pI 7.7) with a mol. wt of 23,000 and was rich in Gly, Glx and Asx but devoid of Met. Analysis of the purified toxin by a protein sequencer afforded no N-terminal amino acid. In addition to C. japonica, two species of freshwater clams belonging to the genus Corbicula, C. leana and C. sandai, were newly found to be toxic, although much less potent than C. japonica. Despite the difference in anatomical distribution of toxins among the three species of Corbicula clams, both C. leana and C. sandai toxins were closely similar in stability and mol. wt to the C. japonica toxin.

Involvement of phosphoinositide-3-kinase and p70 S6 kinase in regulation of proliferation of rat lactotrophs in culture

Phosphoinositide-3-kinase (PI-3K) and p70 S6 kinase (p70S6k) are suggested as important molecules for mediating mitogenic actions of growth factors and cytokines in a variety of cell types. The purpose of the present study was to investigate whether these kinases were involved in mediation of the mitogenic actions of not only the growth factor insulin but also cyclic adenosine monophosphate (cAMP) and estrogen on rat cultured lactotrophs. Treatment with wortmannin or LY294002, a PI-3K inhibitor, or rapamycin, a p70S6k inhibitor, decreased basal levels of 5-bromo-2-deoxyuridine (BrdU)-labeling indices of lactotrophs in a dose-dependent manner. These inhibitors were effective in blocking an increase in BrdU-labeling indices induced by insulin. LY294002 and rapamycin also suppressed an increase in BrdU-labeling indices induced by forskolin, an adenylate cyclase activator, or dibutyryl cAMP, a membrane-permeable cAMP analog, as well as that induced by estradiol, a physiologic extracellular activator of lactotroph proliferation. However, the dibutyryl cAMP-, but not insulin-induced proliferation, acquired a resistance to LY294002 and rapamycin by pretreatment with bromocriptine, a dopaminergic agonist that is able to suppress lactotroph proliferation. These results suggest that the mitogenic actions of cAMP and estradiol on rat lactotrophs are mediated by PI-3K and p70S6k, and that dopaminergic inhibition modifies the PI-3K and p70S6k dependence of the regulation of lactotroph proliferation.

Differential regulation of prolactin release and lactotrope proliferation during pregnancy, lactation and the estrous cycle

The proestrous surge of prolactin (PRL) secretion and subsequent proliferation of lactotropes at estrus have been suggested to be induced by a common hypothalamic hormone. We investigated changes in lactotrope proliferation at other reproductive stages of female rats when PRL secretion was stimulated. To assess proliferative activity of lactotropes, incorporation of 5-bromo-2'-deoxyuridine (BrdU) into DNA was measured by double immunostaining for PRL and BrdU. BrdU-labeling indices, determined by BrdU injections at 10.00 h, revealed low levels of proliferative activity of lactotropes at the reproductive stages including diestrus, days 6 and 13 of pregnancy, and day 6 of lactation while high levels were detected on estrus and the day of parturition. When BrdU-labeling indices were determined at 3-hour intervals through day 6 of pregnancy to find an increase in lactotrope proliferation which might occur at times other than 10.00 h, proliferative activity of lactotropes remained at low levels with a slight increase in the afternoon. Such a diurnal change as observed in early pregnancy was not detected on day 13 of pregnancy. In contrast, short-interval determinations of BrdU-labeling indices during a period from day 20 of pregnancy to day 2 of lactation revealed a marked increase in proliferative activity on the day of parturition with a peak at 18.00 h, which was comparable to that observed at estrus. To investigate involvement of ovarian steroids in suppression of lactotrope proliferation as observed during early pregnancy and lactation, ovariectomized and pup-removed lactating rats were given one of treatment combinations of estradiol and suckling. In pup-removed lactating rats, estradiol treatment alone induced neither a PRL surge nor an increase in BrdU-labeling indices. Suckling stimuli, which were effective in increasing serum PRL concentrations irrespective of estradiol treatment, elicited a marked increase in BrdU-labeling indices in the presence of estradiol but not in its absence. These results suggest that proliferative activity of rat lactotropes does not necessarily correlate with PRL secretion during pregnancy and lactation. In contrast to PRL release, lactotrope proliferation requires both a hypophysiotropic stimulatory input from the hypothalamus and a sensitizing action of estradiol, an observation which may account for the fact that proliferation does not occur during pregnancy and lactation in spite of elevated PRL release.

[A patient with epilepsy, congenital alopecia and mental retardation: combination of atypical absence in waking and nocturnal partial seizure]

We report a 7-year-old girl with epilepsy, congenital alopecia, and mental retardation. She was hairless at birth. Very scanty hair, eyebrows and eyelashes appeared at 2 years of age. Developmental delay was first recognized at 6 years. Nocturnal partial seizures occurred at 4 years, and atypical absence in waking at 6 years. Electroencephalogram showed spike-waves in the centrotemporal area which increased and developed into a generalized continuous spike and wave complexes upon sleeping at the age of 7 years 1 month. Ictal electroencephalogram in atypical absence showed generalized 3 c/s spike and wave complexes. Skin biopsy of the scalp showed scanty, immature hair follicles and immature sebaceous glands. Whether this case is related to ectodermal dysplasia is unclear.

[Epileptogenesis of acute encephalitis and acute encephalopathy: epilepsy with its onset in the acute phase and without a latent period]

Epileptogenesis was evaluated in 60 patients with acute encephalitis and in 10 patients with acute encephalopathy. Forty-seven patients have been seizure-free during for more than three years' follow-up (Group III). On the other hand, 23 patients developed epilepsy. Among them, 18 patients developed epilepsy after a latent period of 1 month to 2 3/12 years (Group I). In Group I, a younger age of the onset, a long period of disturbed consciousness and a high activity of CSF neuron-specific enolase (NSE) was associated with refractory epilepsy. The other five patients had continuous seizures from the acute phase of encephalitis without a latent period (Group II). They had more than 2 types of partial motor seizures which occurred frequently during the acute phase of encephalitis. The NSE activity in the CSF of patients in Group II was less than 50 ng/ml, being similar to those in Group III. The epilepsy in Group II, however, was the most refractory. The reason for the development of this continuous refractory epilepsy remained obscure.

Mitogen-activated protein kinase-dependent stimulation of proliferation of rat lactotrophs in culture by 3',5'-cyclic adenosine monophosphate

Intracellular cAMP regulates cell proliferation as a second messenger of extracellular signals in a number of cell types. We investigated, by pharmacological means, whether an increase in intracellular cAMP levels changes proliferation rates of lactotrophs in primary culture, whether there are interactions between signal transduction pathways of cAMP and the growth factor insulin, and where the dopamine receptor agonist bromocriptine acts in the cAMP pathway to inhibit lactotroph proliferation. Rat anterior pituitary cells, cultured in serum-free medium, were treated with cAMP-increasing agents, followed by 5-bromo-2'-deoxyuridine (BrdU) to label proliferating pituitary cells. BrdU-labeling indices indicative of the proliferation rate of lactotrophs were determined by double immunofluorescence staining for PRL and BrdU. Treatment with forskolin (an adenylate cyclase activator) or (Bu)2cAMP (a membrane-permeable cAMP analog) increased BrdU-labeling indices of lactotrophs in a dose- and incubation time-dependent manner. The cAMP-increasing agents were also effective in increasing BrdU-labeling indices in populations enriched for lactotrophs by differential sedimentation. The stimulatory action of forskolin was observed, regardless of concentrations of insulin that were added in combination with forskolin. Inhibition of the action of endogenous cAMP by H89 or KT5720, a protein kinase A inhibitor, attenuated an increase in BrdU-labeling indices by insulin treatment. On the other hand, the specific mitogen-activated protein kinase inhibitor PD98059, which was effective in blocking the mitogenic action of insulin, markedly suppressed the forskolin-induced increase in BrdU-labeling indices. (Bu)2cAMP antagonized not only inhibition of BrdU labeling indices but also changes in cell shape induced by bromocriptine treatment, although forskolin did not have such an antagonizing effect. These results suggest that: 1) intracellular cAMP plays a stimulatory role in the regulation of lactotroph proliferation; 2) cAMP and insulin/mitogen-activated protein kinase signalings require each other for their mitogenic actions; and 3) the antimitogenic action of bromocriptine is, at least in part, caused by inhibition of cAMP production.

Distribution of prolactin-releasing peptide-immunoreactive neurons in the rat hypothalamus

A newly identified hypothalamic peptide whose specific receptors are present in the anterior pituitary gland is a selective and potent stimulator of prolactin secretion and is therefore termed prolactin-releasing peptide (PRP). We investigated the distribution of PRP-containing neurons in the hypothalamus of female rats by immunocytochemical techniques. Immunocytochemistry using a specific antibody raised to PRP revealed that PRP-immunoreactive perikarya were located in the posteroventral part of the dorsomedial nucleus of the hypothalamus. PRP-immunoreactive nerve terminals were present in high concentrations in a region ventral to the bed nucleus of the stria terminalis, but scarcely observed in the external layer of the median eminence in which well known hypothalamic hormones such as growth hormone-releasing hormone and somatostatin were abundantly detected. This specific distribution in the hypothalamus suggests a novel route of the hypophysiotropic action of PRP.

Enhancement by 1-oleoyl-2-docosahexaenoyl phosphatidylcholine of long-term potentiation in the rat hippocampal CA1 region

We reported previously that administration of 1-oleoyl-2-docosahexaenoyl-sn-glycero-3-phosphorylcholine (ODHPC), a kind of phosphatidylcholine, enhanced discriminatory shock avoidance learning in rats. Since long-term potentiation (LTP) of the hippocampus has been suggested to be a physiological substrate of some forms of memory, we investigated the effects of ODHPC on LTP in the rat hippocampal CA1 region. LTP in the amplitude of population spikes in the CA1 region was induced by tetanic stimulation in anesthetized rats. ODHPC significantly increased magnitudes of LTP in a dose-dependent manner when injected intraperitoneally 20 min before inducing LTP. However, administration of 1,2-dioleoyl-sn-glycero-3-phosphorylcholine, in which only docosahexaenoyl residue of ODHPC was replaced with oleoyl residue, did not affect LTP. These results suggest that ODHPC enhances hippocampal LTP by its specific conformation.

Effects of an antiarrhythmic drug A-2545 on canine ventricular arrhythmia models; comparison with mexiletine and flecainide

We investigated effects of a new Na+ channel blocking antiarrhythmic drug, A-2545, N-3 (2,2,5,5-tetramethyl-3-pyrroline-3-carboxamido)-propyl-phthalimide-hydro chloride, on various canine ventricular automaticity arrhythmias induced by two-stage coronary ligation, digitalis and adrenaline, and compared them with those of mexiletine. A-2545 showed antiarrhythmic effects, significantly decreasing the arrhythmic ratio of 24-h and 48-h coronary ligation-, digitalis- and adrenaline-induced automaticity arrhythmias. The antiarrhythmic plasma concentrations (IC50) of A-2545, 2 mg kg(-1) 10 min(-1), i.v., for 24-h and 48-h coronary ligation-, digitalis- and adrenaline-induced arrhythmias were 1.8, 1.3, 5.8 and 3.7 microg ml(-1), respectively, and that calculated for oral A-2545 (25 mg kg(-1)) in 24-h coronary ligation-induced arrhythmia was 1.8 microg ml(-1). A-2545 is specifically potent in suppressing coronary ligation-induced arrhythmias, i.e., decreasing the arrhythmic ratio nearly to zero by oral administration, and among the intravenously given experiments A-2545 was effective at lower concentrations than other arrhythmia models; A-2545, 2 mg kg(-1) 10 min(-1), was equipotent to 5 mg kg(-1) 10 min(-1) mexiletine in suppressing 24-h coronary ligation-induced arrhythmia, indicating that A-2545 is more potent than mexiletine. In order to determine whether A-2545 has arrhythmogenic effects, we used programmed electrical stimulation (PES)-induced reentry arrhythmias in dogs with old myocardial infarction and compared effects of A-2545 and flecainide. A-2545, 2 and 5 mg kg(-1) 10 min(-1), significantly suppressed the PES-induced arrhythmias in all six dogs without aggravating them. These arrhythmias were not markedly suppressed by flecainide either with 1 or 3 mg kg(-1) 1O min(-1); moreover even in one out of six dogs aggravation of arrhythmia was noted after 1 mg kg(-1) 10 min(-1). In conclusion, A-2545 suppressed various canine ventricular arrhythmias, and the antiarrhythmic effect of A-2545 was more potent than that of mexiletine, and A-2545 did not show arrhythmogenic effects compared to flecainide.

D2 dopamine-receptor-mediated inhibition of proliferation of rat lactotropes in culture is accompanied by changes in cell shape

Dopaminergic agonists are effective in vivo in inhibiting lactotrope proliferation and prolactin (PRL)-secreting pituitary tumors. The purpose of the present study was to demonstrate in vitro actions of dopaminergic agents on proliferation and cell shape of rat lactotropes. Anterior pituitary cells cultured with serum-free, chemically defined medium were treated with dopaminergic agents and were labeled with 5-bromo-2'-deoxyuridine (BrdU) for 3 h before the end of culture. BrdU-labeling indices indicative of the proliferation rate of lactotropes were determined by double immunofluorescence staining for BrdU and PRL. Treatment with dopamine for 21 h decreased BrdU-labeling indices of lactotropes in a dose-dependent manner with a nadir at 3 x 10(-7) M. The inhibitory action of 10(-5) M dopamine appeared 15 h after the initiation of treatment and became pronounced with time up to 33 h. The dopamine action was mimicked by treatment with the D2 receptor agonist bromocriptine at concentrations over 10(-9) M. Phase-contrast microscopy revealed that the flat polygonal cell shape of cultured lactotropes had changed to a round refractive cell shape after treatment with dopamine or bromocriptine, and that these changes in cell shape exactly paralleled those in the BrdU-labeling index. The changes in cell shape of lactotropes were accompanied by changes in subcellular distribution of actin filaments. Pretreatment with 10(-7) M eticlopride, a D2 receptor antagonist, blocked the dopamine- or bromocriptine-induced changes in both BrdU-labeling index and cell shape. These results suggest that (1) the in vitro experimental system established in the present study is a good model for studying the mechanism of the antiproliferative action of dopamine and (2) D2-receptor-mediated inhibition of proliferation of lactotropes in serum-free culture is closely related to changes in actin organization and cell shape.

Electrical stimulation of the lower midbrain around retrorubral field decreases temperatures of brown fat and rectum in anesthetized Wistar rats

To investigate a neuronal mechanism controlling heat production of brown adipose tissue (BAT), ventral regions of the lower midbrain was stimulated by rectangular electric current (0.1 ms, 1 mA, 5-50 Hz) while recording temperatures of the interscapular BAT (IBAT), rectum and arterial blood pressure in urethane-anesthetized Wistar rats at room temperature of 24-26 degrees C. Unilateral stimulation (10 Hz) for 5 min to the midbrain around the retrorubral field decreased temperatures of IBAT (0.33 +/- 0.03 degrees C, n = 33) and rectum (0.10 +/- 0.01 degrees C). The response was reversed when procaine (10%, 800 nl) was injected into the same locus. The results support the hypothesis that a tonic inhibitory mechanism for metabolic heat production locates around the retrorubral field.

Antiarrhythmic effects of an aconitine-like compound, TJN-505, on canine arrhythmia models

We examined the effects of an aconitine-like compound, TJN-505 (1alpha-16beta-dimethoxy-20-ethyl-14alpha-(4-methox ybenzoyloxy)-aconitan-8,13-diol hydrochloride), on canine arrhythmias provoked by digitalis, two-stage coronary ligation, adrenaline, programmed electrical stimulation, or aconitine. TJN-505 (2-2.5 mg/kg i.v.) suppressed digitalis-, two-stage coronary ligation- and adrenaline-induced ventricular arrhythmias. The antiarrhythmic plasma concentrations (IC50) of TJN-505 for these arrhythmia models were 1.26, 0.94 and 1.31 microg/ml, respectively. TJN-505 (2 mg/kg i.v. followed by the infusion of 0.1 mg/kg per min) prolonged PR, QRS, QTc and JTc intervals and the ventricular effective refractory period and reduced the incidence of programmed electrical stimulation-induced arrhythmias in dogs with 7-day-old myocardial infarction (P < 0.05). TJN-505 (2 mg/kg i.v.) also suppressed the aconitine-induced atrial arrhythmias. In conclusion, TJN-505 suppressed various canine ventricular and atrial arrhythmias and seems to act as a blocker of multiple channels.

Intravenous gammaglobulin therapy of Satoyoshi syndrome

Satoyoshi syndrome is a very rare disease of unknown etiology, characterized by intermittent painful muscle spasms, alopecia, multiple epiphyseal changes, diarrhea and endocrine disorders. We administered intravenous gammaglobulin to a 7-year-old girl with Satoyoshi syndrome. Frequency of muscle spasms and the titers of antinuclear antibody and anti-DNA antibody decreased. This is the first report of gammaglobulin therapy of Satoyoshi syndrome. We suggest that this illness could be related to an autoimmune mechanism.

Brain angiotensin II tonically modulates sympathetic baroreflex in rabbit ventrolateral medulla

The role of endogenous angiotensin II (ANG II) at the level of the rostral (RVLM) and caudal ventrolateral medulla (CVLM) in the control of sympathetic baroreflex function was investigated in urethan-anesthetized rabbits. The baroreflex relationship between mean arterial pressure and integrated renal sympathetic nerve activity (RSNA) was compared before and during microinfusion of saralasin, an ANG II receptor antagonist into RVLM or CVLM. The infusion of saralasin (20 pmol/min) into RVLM reduced the upper plateau, the range, and the range-dependent gain of the baroreflex, as well as the resting level of RSNA. The infusion of saralasin into CVLM augmented the upper plateau, the reflex range, and the range-dependent gain, whereas it did not alter the resting level of RSNA or mean arterial pressure. These results suggest that 1) the ANG II networks in RVLM are tonically active, influencing the resting level of the sympathetic outflow and facilitating the sympathetic baroreflex function, and 2) the ANG II networks in CVLM do not significantly influence the sympathetic activity in the resting state but exert an inhibitory effect on the baroreflex response when arterial pressure falls below the resting level.

Estradiol-induced diurnal changes in lactotroph proliferation and their hypothalamic regulation in ovariectomized rats

Pentobarbital anesthesia during the proestrous afternoon delays proliferation of lactotrophs of the anterior pituitary from estrus to diestrus 1 in cycling female rats. We determined whether estradiol treatment induced diurnal changes in rates of lactotroph proliferation in ovariectomized rats, and if so, examined whether hypothalamic neural activity was involved in the occurrence of the estradiol-induced diurnal changes. Dispersed anterior pituitary cells were obtained from ovariectomized rats bearing estradiol implants that had been treated with 5-bromo-2'-deoxyuridine (BrdU) 3 h before decapitation. BrdU-labeling indices representative of the proliferation rate of lactotrophs were determined by double immunofluorescence staining for BrdU and PRL. After treatment of ovariectomized rats with estradiol on day 0, BrdU-labeling indices of lactotrophs as determined by injecting BrdU at 1000 h increased markedly with time peaking on days 4-7. Levels of BrdU-labeling indices at 1000 h on day 4 were 2.8-fold higher than those at 2200 h on day 3 or 4 after estradiol treatment. However, levels of BrdU-labeling indices at 1000 h on day 14 were 35% lower than those at the same time on day 4 and did not differ from those at 2200 h on day 13 or 14. In addition, a difference in BrdU-labeling indices as observed between 1000 and 2200 h on day 4 in the ovariectomized rats was not detected in estradiol-treated orchidectomized male rats. Serial determinations of BrdU-labeling indices throughout day revealed that the difference in BrdU-labeling indices between 1000 and 2200 h on day 4 in the ovariectomized rats reflected estradiol-induced diurnal changes that were characterized by a peak between 0700-0900 h and a nadir between 1900-2200 h. Pentobarbital injected at 0900 or 2100 h on day 3 decreased slightly high levels of BrdU-labeling indices at 0800 h on day 4. However, pentobarbital injection at 1345 h on day 3, which was effective in blocking estradiolinduced surges of LH and PRL secretion, suppressed markedly the high levels at 0800 h on day 4. In these pentobarbital-blocked rats, the diurnal changes in BrdU-labeling indices whose peak would normally have occurred at 0700-0900 h on day 4 were delayed not by the time corresponding to the duration of pentobarbital anesthesia but exactly by 24 h. These results suggest that 1) hypothalamic and sexually dependent diurnal changes in lactotroph proliferation can be induced by short-term estradiol treatment in ovariectomized rats as well as in cycling rats, and 2) estradiol treatment for 14 days rather prevents the diurnal changes in lactotroph proliferation.

Effects of the antihypoxic and neuroprotective drug, lubeluzole, on repolarization phase of canine heart assessed by monophasic action potential recording

The cardiovascular effects of the antihypoxic and neuroprotective drug, lubeluzole, were investigated using beagle dogs anesthetized with halothane. Endocardial-contact electrode catheter was used for continuous monitoring of monophasic action potential (MAP), which could provide a precise information of repolarization phase. Intravenous administration of an efficacious dose of lubeluzole (0.63 mg/kg, n = 6) slightly decreased both the heart rate and the blood pressure. It did not change PQ interval and QRS width, while it significantly prolonged QT interval, corrected QT (QTc) and the duration of the MAP during the observation period over 60 min. The effects of drug on repolarization phase were late-onset and long-lasting compared with the time course of plasma drug concentrations, which changed as predicted by the two-compartment theory of pharmacokinetics. Additional injection of lubeluzole (2.5 mg/kg, n = 6) showed qualitatively similar changes to those of lower dose, and did not induce the cardiovascular collapse in any dog. Neither afterdepolarization nor ventricular escaped beat was detected during the observation period. The drug concentration in cardiac tissue was correlated linearly with the plasma drug concentration at 60 min after the second drug administration. These results indicate that lubeluzole exerts only minor cardiovascular effects except the prolongation of the repolarization period. The monitoring of plasma drug concentration may be helpful to estimate the steady-state distribution of drug to the heart, but less helpful to predict the QT prolongation. In future clinical trials, care must be taken with patients, especially those at risk to have prolonged repolarization.

Long-term potentiation in the rat hippocampal CA1 region is inhibited selectively at the acquisition stage of discriminatory avoidance learning

Long-term potentiation (LTP) of hippocampal synaptic efficacy has been regarded as a synaptic model of learning and memory. We examined whether the induction of LTP in the hippocampal regions was altered with the advance of discriminatory avoidance learning. Evoked potentials in the CA1 region or dentate gyrus were recorded before and after tetanic stimulation in anesthetized rats which had been given training sessions 24 h before. LTP of the amplitude of population spikes and the slope of excitatory postsynaptic potentials recorded in the CA1 region was smaller in rats at a learning stage 24 h after the avoidance rate had first been significantly increased than in naive rats. The magnitude of LTP was not altered in rats which had been exposed to the first training session or in those which had received overtraining. The inhibition of LTP in the CA1 was neither due to stress accompanied with training nor liberation from the stress by learning avoidance response. In contrast, LTP induced in the dentate gyrus was rather enhanced at the learning stage when LTP in the CA1 was inhibited. The results suggest that the acquisition of discriminatory avoidance learning selectively inhibits LTP in the hippocampal CA1 region.

Procaine microinjection into the lower midbrain increases brown fat and body temperatures in anesthetized rats

A tonic inhibitory mechanism on heat production was studied by microinjecting procaine into various regions of the brain while recording temperature changes of the interscapular brown adipose tissue (IBAT) and rectum in urethane-anesthetized rats at room temperature of 23-25 degrees C. Procaine microinjected bilaterally (10%, 1.0 mu l/site, 1.5 mm to midline) into the midbrain and the upper- to mid-pontine area of the reticular formation increased temperatures of the IBAT and rectum. The highest temperature rise (1.02 +/- 0.11 degrees C for IBAT, 0.64 +/- 0.06 degrees C for rectum) with the shortest onset latency (1.5 +/- 0.3 min for IBAT, 4.6 +/- 1.1 min for rectum) was observed when procaine was injected into the lower midbrain (the area between 6 and 7 mm posterior to the bregma, and 6.5 to 8.5 mm deep from the cortical surface). These regions include the retrorubral field, pedunculopontine tegmental nucleus, and rubrospinal tract. Procaine-induced IBAT and rectal temperature increases were dose-dependent, and reproduced reliably from the same injection site of the same animal. Intravenous indomethacin, a prostaglandin H synthase inhibitor, did not affect procaine-induced temperature rise, and propranolol, a beta-blocker, completely blocked it. These results suggest that microinjected procaine exerts its local anesthetic effect and release a tonic inhibition resulting in a disinhibition-induced temperature increase through the enhanced central sympathetic outflow. They support the hypothesis that a bilateral tonic inhibitory mechanism on heat production exists in the lower midbrain.

A quantitative analysis of testosterone action on FSH secretion from individual pituitary cells using the cell immunoblot assay

We investigated the effects of testosterone on FSH secretion from male rat anterior pituitary cells in culture at the single cell level. Anterior pituitary cells cultured with or without 10 ng/ml testosterone for 72 h were mono-dispersed and subjected to cell immunoblot assays for FSH. Cell blots specific for FSH were quantified by means of a microscopic image analyzer. The number of FSH-secreting cells detected as immunoreactive cells blots on the transfer membrane represented 4.1% of total pituitary cells applied on the membrane. The amount of FSH secreted by single cells varied from < 20 to > 8,000 fg/cell/h. The number of FSH-secreting cells was not changed by the addition of 10 ng/ml testosterone into the culture medium. Testosterone administration increased the mean FSH secretion by 64% after 3 h incubation, resulting in a shift to the right in the frequency distribution of FSH secretion from single cells. The total amount of FSH, namely the sum of FSH secreted by each FSH-secreting cel, was increased by 92% by the addition of testosterone. However, mean amounts of FSH secretion by the top ten cells of the largest secretor subgroup (> 5 pg/cell/3 h) were not different between control and testosterone-treated groups. The present study analyzed, for the first time, FSH secretion from rat anterior pituitary cells at the single cell level. The results suggest that stimulation by testosterone of FSH secretion in vitro is not due to an increase in the number of FSH-secreting cells but to an increase in FSH secretion from each cell.

Mammosomatotroph adenoma cells secrete both growth hormone and prolactin

Pituitary adenoma cells from a mammosomatotroph adenoma obtained from a 21-year-old female presenting with acromegaly and amenorrhea were investigated by sandwich cell immunoblot assay, immunohistochemistry, and electron microscopy. The new, simple technique of sandwich cell immunoblot assay could detect two hormones secreted in the same one cell, and found that 89% of mammosomatotrophs secreted both growth hormone (GH) and prolactin (PRL). Immunohistochemistry showed that the tumor cells were positive for both GH and PRL. Electron microscopy showed cells contained granules ranging in size form 150 to 500 nm. This is the first demonstration of both GH and PRL in the same mammosomatotroph cell. Sandwich cell immunoblot assay can measure the amount of secreted hormone, allowing a new approach to the investigation of mammosomatotroph adenomas.

Hopkins syndrome: T2-weighted high intensity of anterior horn on spinal MR imaging

Hopkins syndrome is a poliomyelitis-like illness manifesting flaccid paralysis of an extremity in the recovery stage after an asthmatic attack. A 7-year-old boy who developed acute flaccid paralysis of the left upper extremity 4 days after an asthmatic attack is reported. T2-weighted magnetic resonance imaging of the cervical spine revealed a local high-intensity area in the left anterior horn at the C4 to C6 level. There have been few pathologic or radiologic studies of this syndrome. We suspect that the cause is an anterior horn lesion.

Pentobarbital anesthesia during the proestrous afternoon blocks lactotroph proliferation occurring on estrus in female rats

Estradiol stimulates the synthesis and secretion of PRL and lactotroph proliferation, and its long-term administration induces PRL-secreting pituitary tumors. We examined changes in the number of proliferating lactotrophs throughout the estrous cycle in female rats and the involvement of the brain in the regulation of the lactotroph proliferation by anesthetizing with pentobarbital. Female rats revealing regular 4-day estrous cycles were injected ip with the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) 3 h before decapitation to label DNA-replicating cells. Dispersed anterior pituitary cells obtained from these rats were stained for PRL and BrdU with a double labeling immunofluorescence technique. The rate of lactotroph proliferation was represented by the BrdU-labeling index (BrdU-labeled lactotrophs as a percentage of total lactotrophs counted). Lactotrophs from rats injected with BrdU at 1000 h showed a high BrdU-labeling index of 2.6% on estrus, whereas they showed almost undetectable levels of the BrdU-labeling index during the other stages of the estrous cycle. The anterior pituitary cells other than lactotrophs were scarcely labeled during any stages. The BrdU-labeling index began to rise by the midnight between proestrus and estrus, peaked between 0800 and 1200 h, and returned to undetectable levels by the midnight between estrus and diestrus I. Pentobarbital (35 mg/kg, i.p.) injected at 1345 h on proestrus, which was effective in blocking ovulation on estrus, eliminated completely the increase in the BrdU-labeling index as determined by BrdU injection at 1000 h on estrus. In contrast, the high BrdU-labeling index on estrus was partly suppressed to a level of 1.4% by pentobarbital injection at 0900 or 2100 h on proestrus. The rats injected with pentobarbital at 1345 h on proestrus did not show any increases in the BrdU-labeling index even after BrdU injection was delayed from 1000 to 1400 h on estrus. However, a high BrdU-labeling index of 3.7% was obtained in these animals when BrdU was injected at 1000 h on diestrus I. We conclude that 1) lactotrophs of cycling female rats proliferate selectively on the day of estrus; and 2) the proliferation of lactotrophs on estrus is not due to a direct action on the anterior pituitary of estradiol secreted from the ovaries but triggered by neural events occurring during the proestrous afternoon, which are closely related with the regulation of preovulatory surges of gonadotropin and PRL secretion.

Dopamine responsiveness of human prolactinoma cells as determined by the reverse hemolytic plaque assay

The responsiveness in vivo to dopamine of prolactin (PRL) secretion in patients with prolactinoma was compared with that in vitro of single cells obtained from the same prolactinomas by surgical operations. Six patients with prolactinoma showing various degrees of hyperprolactinemia were challenged by bromocriptine suppression test (2.5 mg, peroral) before operation. Bromocriptine administration caused a decrease in the serum PRL concentration ranging 24-95% and there was no correlation between the basal PRL level and bromocriptine-induced inhibition. Monodispersed pituitary cells obtained from the prolactinomas by operation were subjected to a reverse hemolytic plaque assay for PRL to determine PRL secretion at the single cell level under basal conditions as well as in response to dopamine. The percentage of plaque-forming cells under basal conditions ranged 15-55% among the prolactinomas. The percentage of plaque-forming cells and plaque area were decreased in a dose-dependent manner by 10(-7) - 10(-5) M dopamine for the pituitary cells obtained from some adenomas but not for those from other adenomas. When the inhibition rates in vitro due to 10(-5) M dopamine in these two parameters were compared with the inhibition rate in vivo in the serum PRL concentration due to bromocriptine, it was found that there was a significant correlation between them. These results show that the reverse hemolytic plaque assay can be used to determine in vitro responsiveness to dopamine of PRL secretion from single prolactinoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of a proteinaceous toxin in the brackishwater clam (Corbicula japonica)

Water extracts from the brackishwater clam (Corbicula japonica) were found to be lethal to mice upon i.v. injection. Muscular tissues (foot muscle, adductor muscle, mantle muscle, mantle and siphon) were all toxic while gill and viscera (mid-gut gland, testis and ovary) were nontoxic; the highest toxicity was observed with foot muscle. The toxin was judged to be a thermolabile, basic protein with a mol. wt. of about 13,000.

Somatotropes and thyrotropes in the rat anterior pituitary gland cosecrete substance P: analysis by the sandwich cell immunoblot assay

Substance P (SP) which is synthesized and secreted by anterior pituitary cells has been suggested to alter pituitary functions as a local modulator. We determined which cell type(s) of rat anterior pituitary gland secretes SP. A new technique, named the sandwich cell immunoblot assay (CIBA), was developed to identify two protein substances that are secreted simultaneously from the same cells. Monodispersed anterior pituitary cells were sandwiched with pairs of transfer membranes and incubated to absorb secretory substances on the membranes. Small reference points for identifying the location of cell blots were simultaneously put on the pairs of transfer membranes after the incubation. The validity of the sandwich CIBA was revealed by the following: (1) cell blots were detected at the same locations on the pairs of transfer membranes that were immunostained with the same antisera against the anterior pituitary hormones, and (2) the areas of these cell blots detected at the same locations on different membranes correlated well. When one of the pair of transfer membranes was immunostained for SP and the remaining immunostained for one of the anterior pituitary hormones, it was found that 78 and 27% of SP-immunoreactive cell blots showed also GH and TSH immunoreactivity, respectively. None of the SP-immunoreactive cell blots showed immunoreactivity for PRL, ACTH, LH or FSH. These results suggest that the sandwich CIBA is useful to identify two substances cosecreted from a cell and that a subpopulation of rat somatotropes or thyrotropes cosecretes SP.

Spontaneous acetylcholine release in the hippocampus exhibits a diurnal variation in both young and old rats

Extracellular levels of acetylcholine (ACh) in the hippocampus were measured by the microdialysis method in freely moving young (3-4 months old) and old (18-24 months old) female rats over a period of 24 h to examine the effect of aging on hippocampal ACh release. Hippocampal ACh release during a 24-h period exhibited a diurnal variation with higher levels during the dark cycle than during the light cycle in old rats as well as young rats. The present study suggests that a diurnal variation in ACh release is maintained fairly well until the rats are at least 24 months old.

[Muscle fiber involvement in Lowe syndrome]

Although it is well known fact that patients with Lowe syndrome have a delay in developmental milestones, muscle hypotonia and weakness, no detailed pathologic study to explain the muscle symptoms is available. In two patients with Lowe syndrome aged 22 years and 14 years, respectively, the biopsied biceps brachii muscles showed no significant morphologic changes except for small caliber fibers measuring almost 1/3 of the normal size. Although the muscle fiber type distribution is normal with no increase in undifferentiated type 2 C fibers, there remains a possibility of a certain defective neural influence on developing muscle fibers or metabolic defect. The muscle fiber immaturity is probably responsible for muscle weakness and hypotonia in this syndrome.

Intraperitoneal injection of 1-oleoyl-2-docosahexaenoyl phosphatidylcholine enhances discriminatory shock avoidance learning in rats

Effects of injection of 1-oleoyl-2-docosahexaenoyl-sn-glycero-3-phosphorylcholine (ODHPC) on learning ability were investigated in rats using discriminatory shock avoidance learning task. When ODHPC (2 mumol) was intraperitonealy administered 5 min before the beginning of the first trial of learning task from the second to fifth sessions, avoiding rates of the ODHPC-injected group were significantly higher than those of the control group. However, any injection of ODHPC derivatives, such as 1-oleoyl-2-docosahexaenoyl-diacylglycerol, 1,2-dioleoyl-sn-glycero-3-phosphorylcholine, glycerophosphorylcholine, docosahexaenoate, oleate and choline chloride, did not affect learning. These results suggest that intraperitoneal ODHPC injection enhances learning ability by its specific conformation.

[Analytical methods at the single cell level for measuring secretory functions of anterior pituitary cells]

It has been shown that cells that synthesize and secrete a specific hormone differ quantitatively and qualitatively one another for basal and secretagogue-induced secretion. Four analytical methods are at present available for measuring secretory activity of endocrine cells at the single cell level. These include the reverse hemolytic plaque assay, cell membrane capacitance method, quinacrine fluorescence method, and cell immunoblot assay (CIBA). Each method has advantages as well as disadvantages. The CIBA has several variants such as sequential and sandwich CIBAs. It is possible to determine hormone secretion repeatedly from single cells and to identify multihormones that are cosecreted from a cell by using these variants.

Measurement of the secretion of a small peptide at the single cell level by the cell immunoblot assay: thyroidectomy increases the number of substance P-secreting anterior pituitary cells

The present study developed a technique for quantification of a small peptide secreted by single endocrine cells and investigated the cellular basis for the effects of endocrine environments on their secretion by using this technique. To quantify substance P (SP) secreted by monodispersed rat anterior pituitary cells and to estimate the relative abundance of SP-secreting cells, the cell immunoblot assay was improved by several modifications, including the use of incubation chambers and addition of immunostaining procedures of fixation by paraformaldehyde and elimination of nonspecifically stained blots. Single pituitary cells formed SP-specific blots on protein-blotting transfer membranes that constituted a floor portion of the incubation chamber. A combination of microscopic image analysis and SP standard curve made it possible to quantify the amount of SP stained as blots. SP secretion from single pituitary cells showed a large variation ranging from 0.14-144 fg/cell.h. The mean SP secretion and the number of SP-secreting cells were increased in an incubation time-dependent manner, with plateau levels of 20.3 fg/cell and 30.2 in a chamber area of 8 x 8 mm, respectively, at 3 h. Thyroidectomy significantly increased the number of SP-secreting cells and the total amount of SP secretion but decreased the mean SP secretion from single pituitary cells. This decrease in the mean SP secretion in the thyroidectomized rats was found to be due to a relative abundance of cells that secrete small amounts of SP. The present study demonstrates that the cell immunoblot assay is useful for quantifying peptide secretion at the single cell level and suggests that thyroidectomy-induced increase in SP secretion from anterior pituitary cells is not due to an increase in SP secretion per cell but due to an increase in the number of SP-secreting cells.

Analysis of the secretion from single anterior pituitary cells by cell immunoblot assay

The CIBA is very useful in quantifying hormone secretion from single endocrine cells. Variations of this assay can extend its power for evaluating the proportion of hormone-secreting cells in a cell population, determining the responsiveness of individual cells to a particular secretagogue and identifying multihormones that are simultaneously secreted by the same cells. By using the CIBA and its variations, mammotrophs were shown to be heterogeneous with respect to the responsiveness to DA and TRH and cosecretion of PRL and GH. Furthermore, the fact that SP secretion from pituitary cells was increased by thyroidectomy via an increase in the number of SP-secreting cells indicates the possibility that the CIBA can clarify mechanisms underlying changes in hormone secretion and intercellular signaling at the cellular basis.

Lactotrophs secreting small amounts of prolactin reveal great responsiveness to thyrotropin-releasing hormone: analysis by the sequential cell immunoblot assay

The effects of TRH on PRL secretion from individual lactotrophs of female rats were investigated by using a sequential cell immunoblot assay. The same pituitary cells cultured on coverslips were first incubated to determine basal secretion of PRL and subsequently challenged by one of various concentrations of TRH. The PRL secreted from the single lactotrophs was absorbed on protein-blotting transfer membranes, immunostained, and quantified by microscopic image analysis. When no TRH was added to the medium used in the second incubation (controls), the amount of PRL secreted from individual lactotrophs was 93% of that secreted in the first incubation. Treatment with 3 x 10(-10)-10(-7) M TRH in the second incubation increased in a dose-dependent manner the proportion of lactotrophs whose PRL secretion was significantly greater than confidence limits for PRL secretion in the controls. However, the percentage of TRH-responsive lactotrophs remained less than 50% even at a maximally effective concentration of TRH. Proportions of the TRH-responsive lactotrophs were significantly greater in cells that secreted small amounts of PRL under basal conditions than in those that secreted large amounts. Furthermore, the small, but not the large, secretors showed a significant increase in mean absolute amounts of PRL secreted by 10(-7) M TRH, which represented no less than 45% of all PRL secreted from the lactotroph population by the TRH treatment. These results indicate that 1) there is a heterogeneity with respect to lactotroph responsiveness to TRH and that 2) a population of lactotrophs that secrete small amounts of PRL under basal conditions contains a much larger proportion of TRH-responsive lactotrophs than does a population of lactotrophs that secrete large amounts of PRL.