Ultrastructural recognition of gap junctions between melanocytes in human vestibular organs by tannic acid containing fixative preparation and freeze-fracture technique

BACKGROUND

The purpose of the present study was to obtain additional information about the ultrastructural characteristics of gap junctions between melanocytes in human vestibular organs by using various ultrastructural techniques.

METHODS

All materials were obtained from patients with vestibular schwannoma. Glutaraldehyde-fixed specimens and specimens treated with fixative containing glutaraldehyde and tannic acid were processed for conventional ultrathin transmission electron microscopic (TEM) examination. Others were prepared for freeze-fracture replica and examined by TEM.

RESULTS

Gap junctions were present between adjacent subepithelial melanocytes. The gaps between the inner leaflets of the apposed plasma membranes at the gap junctions were 10-12 nm, and the gaps between the outer leaflets were 2-4 nm. The intercellular space between the apposed plasma membranes of gap junctions showed the deposition of high electron-dense material in specimens prepared with fixative containing glutaraldehyde and tannic acid. At the highest magnification specimens fixed by glutaraldehyde with or without tannic acid and cut obliquely to the plasma membranes showed periodic substructures with constant repeating lattices or a small porous structure at the junctions. Study by freeze fracture revealed that these gap junctions between melanocytes consisted of 100-200 aggregations of connexon particles that were approximately 8.8 nm in diameter.

CONCLUSIONS

We suggest that melanocytes may construct a cellular network involved in the maintenance of the homeostasis of human vestibular organs through the intimate transmission of various signals or intercellular informations via well-developed gap junctions.

[Evaluation of the factor XIIa assay kit]

The assay for activated coagulation factors has recently been considered to be a useful tool for detecting hypercoagulable state. Measurement of activated factor XI and alpha 1 antitrypsin complex developed by us is the only one measure for detecting contact phase hypercoagulation. The ACTIVATED FACTOR XII kit (Shield Diagnostics) has recently been commercially available, and the reference range was reported in the instruction manual. However, because the recovery rate of purified factor XIIa (XIIa) in normal pooled plasma by this assay kit was strikingly decreased, the effects of inhibitors in plasma, such as low molecular weight serine proteinase inhibitor (diisopropyl fluoro-phosphate, DFP), the specific inhibitor for XIIa (corn trypsin inhibitor, CTI), the main inhibitor for XIIa (C1 inhibitor, C1I) were examined. These three inhibitors and XIIa were incubated for 18 hours, then the XIIa levels of these complexes and the recovery rate in the normal pooled plasma were assayed by this assay kit. The recovery ratios in the normal pooled plasma were; DFP-XIIa 82%, CTI-XIIa 63%, and C1I-XIIa 0%, XIIa without inhibitor 7%. These results suggest that this XIIa kit does not reflect the levels of complexed form of XIIa and inhibitors in plasma samples.

[Consideration of therapeutic choice for grade 3 superficial bladder cancer]

Between January, 1977 and December, 1994, 90 patients with grade 3 (G3) superficial bladder cancer were treated at Yokohama City University Hospital, Yokohama Municipal Hospital and Kanagawa Cancer Center. These patients were clinically observed. The prognostic factors of the patients with G3 superficial bladder tumors were age and growth pattern of tumors. Patients older than 67 showed significantly poor survival compared with younger patients (p < 0.01). Patients with non-papillary sessile tumors showed significantly poor survival compared with the other groups (p < 0.05). The five-year survival rate of the patients with G3 superficial tumors who were treated by total cystectomy was 75%, whereas all the patients who were treated by bladder preservation therapy died within 4 years, the difference being significant (p < 0.05). Eleven patients with G3 superficial bladder tumors died of cancer, and most of these patients had multiple and non-papillary sessile tumors. These findings suggest that the patients with G3 superficial tumors, which are non-papillary sessile tumors, should be treated by radical cystectomy.

[Hemolytic anemia due to abnormalities in erythrocyte nucleotide metabolism]

Abnormalities in erythrocyte nucleotide metabolism are associated with hereditary nonspherocytic hemolytic anemia. Deficiency of adenylate kinase and pyrimidine 5'-nucleotidase and hyperactivity of adenosine deaminase shorten the red cell lifespan. Deficiency of adenylate kinase has been reported in four different families. Although in one family, total absence of this enzymatic activity was documented in one hematologically normal sibling, there is doubt about the capacity of this single enzyme deficiency to produce hemolysis. A deficiency of pyrimidine 5'-nucleotidase is a cause of hemolytic anemia characterized by red cells with basophilic stippling. This enzyme has been reported to catalyze the hydrolytic dephosphorylation of pyrimidine 5'-ribose monophosphate. Red cells of patients contain an increased concentration of pyrimidine nucleotides and reduced form of glutathione. In hyperactivity, the adenosine deaminase activity in erythrocytes may be increased to 100 times the normal level. The high adenosine deaminase activity of erythrocytes depletes adenine nucleotides, inhibiting its metabolism.

Cyclin D1 overexpression in primary hypopharyngeal carcinomas

BACKGROUND

Hypopharyngeal squamous cell carcinomas (HPCS) are associated with an extremely poor prognosis. Generally, conventional clinicopathologic factors have only limited value as prognostic factors for this malignancy. It is therefore clinically important to identify new prognostic factors that accurately reflect the biologic aggressiveness of this malignancy. The amplification and overexpression of the cyclin D1 protooncogene have been reported in a variety of malignancies, and are thought to be related to tumor progression. Based on this phenomenon, the authors immunohistochemically evaluated overexpression of the cyclin D1 gene in 42 cases of primary HPCS. In addition, the immunohistochemical staining of the proliferation marker MIB-1 (Ki-67 antibody) was also performed.

METHODS

Formalin fixed, paraffin embedded biopsy specimens obtained prior to treatment were examined. Cyclin D1 and Ki-67 were detected using monoclonal antibodies by means of the streptavidin-biotin method. The relationship between cyclin D1 overexpression and the stage, histologic grade, presence of lymph node metastases, proliferation index, and survival was then statistically analyzed. The correlation between the proliferation index, other clinicopathologic factors, and survival was also evaluated.

RESULTS

Twenty-three (54.8%) HPCS specimens showed a 20% or greater immunoreactivity for cyclin D1. Cyclin D1 overexpression was related to cervical lymph node metastases (P = 0.037) but not to clinical stage, histologic grade, or the proliferation index. Cyclin D1 negative tumors were associated with a significantly better prognosis (P = 0.023), particularly in patients who underwent multimodality treatment. Finally, the MIB-1 labeling index showed no correlation with either the clinicopathologic parameters or overall survival.

CONCLUSIONS

Based on these findings, cyclin D1 immunohistochemical staining is considered to be useful, not only as a prognostic factor for HPCS, but also as a means of determining the optimum treatment for each individual patient. Conversely, the MIB-1 labeling index appears to have no clinical significance in HPCS.

Alterations of cytochrome P450-dependent monooxygenase activities in Eriocheir japonicus in response to water pollution

Eriocheir japonicus, fresh-water crabs inhabiting rivers and estuaries in Japan, were investigated for cytochrome P450 (CYP)-dependent drug-metabolizing enzyme activities to see if these activities reflect the river pollution gradient. From the laboratory dose-response experiments, we found that the polycyclic aromatic hydrocarbon (PAH) 3-methylcholanthrene induced total CYP contents, ethoxycoumarin O-deethylase activity, and bunitrolol 4-hydroxylase activity in crab hepatopancreas. In the field studies, crabs collected from the river with the highest concentration of PAHs exhibited the highest levels of CYP, the highest activities of benzo[a]pyrene 3-hydroxylase, imipramine 2-hydroxylase, bunitrolol 4-hydroxylase, ethoxycoumarin O-deethylase, and the ability to metabolically activate benzo[a]pyrene, but erythromycin N-demethylase activity was not induced. The correlation between PAH levels and drug-metabolizing enzyme activities in female crabs were not as marked as in male crabs. The levels and activities of CYP did not appear to reflect the concentrations of organochlorines and polychlorinated biphenyl congeners (PCBs) studied in the fat of crab hepatopancreas.

Prognostic significance of Ki-67 labeling index in urothelial tumors of the renal pelvis and ureter

PURPOSE

We evaluated the prognostic significance of the Ki-67 labeling index in 70 patients with primary urothelial tumors of the renal pelvis and ureter.

MATERIALS AND METHODS

Immunohistochemical staining for Ki-67 in archival tumor materials was done by the streptavidin-biotin method.

RESULTS

Univariate survival analysis showed that the prognosis of patients with a high Ki-67 labeling index of 21.7 or more was significantly worse than that of patients with an intermediate labeling index of 13.3 to less than 21.7 (p < 0.01) or a low labeling index of less than 13.3 (p < 0.001). Multivariate survival analysis showed that staining for Ki-67 labeling index was significantly correlated with prognosis (p < 0.01).

CONCLUSIONS

Analysis of Ki-67 labeling index provides useful prognostic information about patients with primary urothelial tumors of the renal pelvis and ureter.

[Extirpation of total urinary tract as a final treatment for asynchronous multicentric urothelial cancer: a case report]

A 48-year-old male patient underwent transurethral resection (TUR) for solitary bladder tumor in January 1985. Pathological finding of the specimen was non-invasive transitional cell carcinoma (TCC) G2 > G1. Following the operation, prophylactic intravesical instillation of antitumor agents, intrapelvic irradiation, and hyperthermia were done for the recurrences. In June 1987, left renal pelvic tumor revealed, and nephroureterectomy was performed. Histological examination of renal pelvic tumor showed TCC G1. Five months later, multiple bladder tumors and right renal pelvic tumor were detected. A total cystectomy, partial nephrectomy and nephrostomy were performed in February and March 1988. Pathology of the bladder and right kidney were TCC G3. One month after these operations, tumors recurred in the rest of the right kidney. Complete remission was achieved after systemic chemotherapy with methotrexate, vinblastine, doxorubicin and cisplatin (M-VAC). In January 1992, right renal pelvic tumor recurred again. After two cycles of M-VAC therapy, the rest of the right kidney was extirpated. Postoperative hemodialysis has been uneventful. He has lived without tumor recurrence for three years after the introduction of hemodialysis.

Role of cholecystokinin (CCK)-A receptor for pancreatic growth after weaning: a study in a new rat model without gene expression of the CCK-A receptor

This work extends a recent observation that Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which have been established as an animal model of non-insulin-dependent diabetes mellitus, show no expression of the cholecystokinin (CCK)-A receptor gene in the pancreas. The CCK-A receptor is known to be involved in regulating pancreatic exocrine function and growth. We examined the growth of the pancreas in terms of wet weight, enzyme compositions, and protein and DNA contents at 5-6 and 24-25 weeks of age in OLETF rats and control (Long-Evans Tokushima; LETO) rats. The pancreatic wet weight increased significantly with age in both OLETF and LETO rats but was significantly lower in OLETF rats than in LETO rats. The total DNA contents in the whole pancreas (cell numbers) were comparable for both strains and increased significantly with age. However, the ratio of protein content to DNA content (the cell size) significantly increased with age in LETO rats, with no increase in OLETF rats. The changes in chymotrypsin, amylase, and insulin with respect to age were in the same direction in both strains: a decrease or no change in total and/or cellular contents of chymotrypsin and insulin and increases in amylase. These results suggest that the CCK-A receptor plays some role in the increase in cell size associated with normal growth of the pancreas from 5 to 25 weeks of age (after weaning).

Rate parameter changes by added albumin in the microsomal oxidative demethylation of deuteriated and non-deuteriated 4-methoxyanisole

Bovine serum albumin (BSA) added to the reaction medium for the oxidative demethylation of 4-methoxyanisole and its "di-CD3" isotopomer ([d6]methoxyanisole), when catalyzed by liver microsomes from untreated rats, decreased the Km values and increased the V(max)/Km (= V/K) values. The Vmax values were not markedly altered. The values for the deuterium isotope effect on V(max) and V/K for the reaction with this isotopomer were between 2.2 and 2.8, and that on Km was close to unity. The magnitude of the isotope effect was not significantly changed by adding BSA. The intramolecular isotope effect with [mono-CD3]4-methoxyanisole ([d3]methoxyanisole) in liver microsomes from untreated rats was between 10.3 and 10.8, which was not significantly changed by BSA. Liver microsomes from rats treated with phenobarbital resulted in the intramolecular isotope effect value in the absence of BSA being between 7.2 and 9.1, which was not significantly altered by BSA. Based on these data, the calculated apparent rate constant for the enzyme-substrate complex formation was markedly increased by up to about 1.9- and 3.5-fold by 1% and 2% of BSA added, respectively.

Effects of intracerebroventricular administration of 6-hydroxydopamine on ouabain-like immunoreactivity in plasma and the hypothalamo-pituitary axis in rats

OBJECTIVE

To examine the role of central mechanisms on the production and release of an ouabain-like factor, the effects of intracerebroventricular injections of 6-hydroxydopamine on the tissue content and on the plasma level of the ouabain-like factor were determined in rats.

METHODS

The vehicle (0.1% ascorbic acid in 0.9% saline) and 6- hydroxydopamine (250 micrograms/rat) were injected into the left lateral ventricle in ether-anaesthetized Wistar rats. Hypothalamus, pituitary, adrenal and venous blood was sampled 24h and 7 days later. The procedure was repeated using another rat group 7 days later. Characteristics of immunoreactive ouabain-like factor were determined by a combination of high-performance liquid chromatography and a highly sensitive enzyme-linked immunosorbent assay for ouabain. The level of the ouabain-like factor in these tissues and in plasma extracts measured by the enzyme-linked immunosorbent assay was compared between the two groups receiving 6-hydroxydopamine and the vehicle.

RESULTS

Twenty-four hours after the intracerebroventricular injections of 6-hydroxydopamine, the ouabain-like factor level in the pituitary, hypothalamus and plasma had decreased significantly, whereas the ouabain-like factor level in the adrenal had not changed. The content of noradrenaline in the hypothalamus was also decreased markedly 7 days later and the content of ouabain-like factor in the pituitary remained low. On liquid chromatography the elution pattern of the ouabain-like factor in plasma and in tissue extracts coincided with that of authentic ouabain.

CONCLUSIONS

Intracerebroventricular treatments with 6-hydroxydopamine elicited decreases in ouabain-like factor contents in the pituitary, the hypothalamus and the plasma. These results suggest that the production and release of ouabain-like factor are closely associated with the brain, particularly the hypothalamus-pituitary axis, and that noradrenergic or dopaminergic neurons, or both, play a key role in this mechanism.

[Recurrent and up-grading bladder cancer in a young female: a case report]

We report a case of superficial bladder cancer in a young female, with grade-up tumor after frequent recurrences. A 29-year-old woman complained of gross hematuria on April 25, 1991. Cystoscopic examination revealed a papillary pedunculated tumor and transurethral resection of bladder tumor (TUR-BT) was performed. Pathological examination showed transitional cell carcinoma (TCC) pT1 grade 1. In spite of prophylactic therapy, such as intravesical instillation of anticancer drugs and radiochemohyperthermia, she suffered frequent recurrences. At the 6th recurrence, the tumor deteriorated to grade 3 on September 2, 1992. Total cystectomy was done on February 15, 1993 because of uncontrollable bleeding from bladder cancer. Convalescence was uneventful, and no evidence of recurrence was present 2.8 years postoperatively.

Pancreatic endocrine dysfunction in rats not expressing the cholecystokinin-A receptor

Cholecystokinin (CCK) has been suggested to modulate insulin output. We have shown that Otsuka Long-Evans Tokushima Fatty (OLETF) rats show little or no expression of the CCK-A receptor gene in the pancreas. We examined whether the CCK-A and CCK-B receptor genes are expressed in the islets and the role of CCK-A receptor in insulin secretion. Gene expressions of CCK receptors were determined by the reverse-transcriptase polymerase chain reaction (RT-PCR) followed by Southern blot hybridization and Northern transfer analysis using LETO rats as controls. Pancreatic endocrine function was examined in perfusion (exogenous CCK stimulation) and meal ingestion (endogenous CCK stimulation) studies. CCK-A receptor mRNA was detected in the islets of LETO rats but not OLETF rats. Expression of the CCK-B receptor gene was detected in both strains by RT-PCR. Insulin secretion was impaired in OLETF rats, but the insulin contents of OLETF and LETO rats were not different. No abnormalities were detected histologically in either strain. These results suggest that the occurrence of pancreatic endocrine dysfunction in OLETF rats may be due to a defect in expression of the CCK-A receptor gene, not to insulin deficiency.

Neurohormonal regulation of pancreatic exocrine function in rats without gene expression of the cholecystokinin-A receptor

Otsuka Long-Evans Tokushima Fatty (OLETF) rats revealed no or reduced expression of the cholecystokinin (CCK)-A receptor gene in the pancreas and that the pancreas of this strain of rats did not respond to CCK stimulation. We examined whether the pancreatic responses to hormonal and neural stimulation except for CCK in OLETF rats were maintained. The pancreatic responses of conscious OLETF rats to various stimuli were examined in vivo and compared with those of control (Long-Evans Tokushima; LETO) rats. Moreover, the levels of expression of CCK-A and -B receptor genes in the small intestine were examined. Pancreatic responses to intravenous injection of secretin and acetylcholine and to intracerebroventricular administration of thyrotropin-releasing hormone were comparable in OLETF and LETO rats. However, responses to intravenous injection of neuromedin C, to intraduodenal injection of capsaicin, and to intragastric injection of a liquid meal were impaired in OLETF rats. CCK-A receptor mRNA was not expressed in the small intestine of OLETF rats but was in LETO rats. The pancreatic responses to various stimuli in OLETF rats were well conserved except for the involvement of CCK-A receptor function. OLETF rats are confirmed as a new experimental model deficient in CCK-A receptor gene expression and represent a useful tool for studying the physiological role of these in vivo.

Effect of 3-methylcholanthrene on bunitrolol metabolism. Kinetics and immunological studies on 4-hydroxylation of bunitrolol catalyzed by two species of cytochromes P450 in rat liver microsomes

Effect of the induction of cytochrome P4501A1 with 3-methylcholanthrene (3-MC) treatment on kinetics of bunitrolol (BTL) 4-hydroxylase activity of rat liver microsomes was investigated. The relationship between the rate and BTL concentration showed monophasic kinetics (KM = 0.74 +/- 0.13 microM) when microsomes from untreated rats were used, whereas microsomes from 3-MC-treated rats showed biphasic kinetics (KM1 = 0.76 +/- 0.13, KM2 = 646 +/- 16 microM). Anti-cytochrome P450 (P450) BTL (P4502D subfamily) antiserum inhibited the reaction > 90% when low concentrations (approximately 10 microM) of BTL were used in both microsomes. However, at high BTL concentrations (approximately 2,000 microM), the inhibition was only up to a half of control in microsomes from 3-MC-treated rats, whereas in microsomes from untreated rats, the rates were suppressed > 90%. Kinetics observed in microsomes from 3-MC-treated rats changed to nearly monophasic, with a KM value corresponding to KM2. Anti-P4501A1 IgG, on the other hand, hardly inhibited the reaction conducted by liver microsomes from 3-MC-treated rats when substrate concentrations were low, whereas at higher concentrations, it inhibited up to 50%, resulting in a monophasic kinetics with a KM value corresponding to KM1. These results clearly indicate that the biphasicity of kinetics in BTL metabolism in liver microsomes from 3-MC-treated rats is caused by the involvement of two P450 species: P450 BTL and P4501A1 in the reaction. This is the first direct evidence to the theoretical hypothesis that the biphasic kinetics of the enzyme reaction is caused by the involvement of at least two enzymes with different kinetic parameters.

Mutually exclusive distribution of the focal adhesion associated proteins and the erythrocyte membrane skeleton proteins in the human fibroblast plasma membrane undercoat

The ends of stress fibers in the basal portion of cells (basal stress fibers) are anchored to focal adhesions, and stress fibers in the apical part of cells (apical stress fibers) are attached to the apical membrane, forming a structure (the apical plaque; KATOH, K. et al. (1995). Cell Motil. Cytoskel., 31: 177-195) resembling the focal adhesion. In addition to these two sites, stress fibers also make lateral contact with the plasma membrane but little is known about the molecular composition of this type of stress fiber-membrane interaction sites. Several actin-membrane association types are known, each employing a different set of proteins, and the focal adhesion and the erythrocyte membrane skeleton are the best characterized systems. We investigated by immunofluorescence microscopy if there is any morphological basis for the involvement of the erythrocyte membrane proteins in the stress fiber-plasma membrane association sites in cultured human fibroblasts. Our results indicated that fodrin (nonerythrocyte type spectrin) and ankyrin were generally associated with the plasma membrane, but that they were clearly excluded from the focal adhesion, the apical plaque and the stress fiber. Thus, it appears that the spectrin and the integrin based actin-membrane association systems are mutually excluded in the fibroblast membrane undercoat. Protein localization at the lateral stress fiber-membrane association site was also studied. Our data indicated that, while talin, vinculin, paxillin, fibronectin receptor and integrin beta 1 were present at the three stress fiber-membrane association sites, vitronectin receptor and integrin alpha v were absent from the apical plaque and the lateral association site. While the plasma membrane at the focal adhesion adheres tightly to a solid substrate, the cell surface of the apical plaque is free. Although the lateral association site faces the substrate, the molecular composition of this site is similar to that of the apical plaque.

The effect of lazaroid (U74500A), a novel inhibitor of lipid peroxidation, on 24-hour heart preservation. A study based on a working model using cross-circulated blood-perfused rabbit hearts

Lazaroid, an inhibitor of iron-mediated lipid peroxidation, has been shown to reduce free radical-mediated injury after ischemia and reperfusion. We thus examined the efficacy of pretreatment with lazaroid (U74500A) in enhancing functional recovery after 24-hr heart preservation. An isolated rabbit heart model perfused with the blood from a support rabbit was used. Before preservation, either U74500A (4 mg/kg, group L; n = 6) or solvent (group S; n = 7) was given to the donor rabbit. After 24-hr preservation with UW solution at 0 degrees C, all hearts were perfused with cross-circulated blood for 60 min with the Langendorff mode followed by 40 min of the working mode. In group S, ventricular fibrillation (Vf) after reperfusion was observed in all hearts, whereas no Vf was observed in the U74500A-pretreated group. In group L, the serum creatine phosphokinase; its isozyme, troponin-T; and serum lipid peroxide levels after 10 min of reperfusion were all significantly (P < 0.05) lower than those in group S. The Frank-Starling curve (indicating the left atrial pressure-aortic flow relationship) showed a significant left and upward shift in group L compared with that in group S (P < 0.0001). The heart pretreated with U74500A showed less ischemia-reperfusion injury, better ventricular function, and a lower lipid peroxide level. We thus conclude that the inhibition of lipid peroxidation with lazaroid appears to offer some potential benefits for long-term heart preservation.

Effects of subtle changes in the SU protein of ecotropic murine leukemia virus on its brain capillary endothelial cell tropism and interference properties

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic variant of Friend MuLV (F-MuLV) that causes a rapidly progressive neurodegenerative disease in susceptible rodents. PVC-211 MuLV, but not the parental F-MuLV, can infect rat brain capillary endothelial cells (BCEC) efficiently, and the major determinant for BCEC tropism of PVC-211 MuLV is localized within the XbaI-BamHI fragment of the viral genome containing the 5' half of the env gene. To further dissect the XbaI-BamHI region for its effects on BCEC tropism, we constructed recombinant viruses between PVC-211 MuLV and F-MuLV and tested their infectivity on a cell line established from rat BCEC. Our results indicated that Glu116-to-Gly and Glu129-to-Lys substitutions in the background of the F-MuLV envelope SU protein were sufficient for conferring BCEC tropism on the virus. Interference studies of these viruses on Rat-1 fibroblastic cells showed that the structure of the SU protein encoded by the XbaI-BamHI region also has significant effects on their affinity for the rat ecotropic MuLV receptor. These results support the possibility that structural elements I and II of the SU protein are important determinants for virus-receptor interaction.

[A case of hydronephrosis with high level of serum Span-1 antigen and CA19-9]

A sixty-year-old woman visited our hospital with a complaint of left flank pain. Laboratory data showed a high level of serum CA19-9. Computerized tomography and ultrasonography revealed left hydronephrosis and hydroureter. No tumors were found in the liver, pancreas, gallbladder, gastrointestinal tract or genitourinary tract. The serum SPan-1 antigen level was elevated to 250 U/ml, and the serum CA19-9 level was also elevated to 580 U/ml. Since urological malignancy was not excluded from these findings, left nephroureterectomy was performed. Pathological findings revealed chronic inflammation, and malignant cells were not found in the resected specimens. Although high levels of SPan-1 antigen and CA19-9 have been reported in benign diseases, both are usually less than 100 U/ml. In this case, serum SPan-1 antigen and CA19-9 levels were extremely high (more than 1,000 U/ml). Since the serum SPan-1 antigen and CA19-9 levels were gradually reduced to normal levels within 4 months after the operation, a possible explanation for the high levels of the two tumor markers is hydronephrosis in the left kidney. We report this interesting hydronephrosis associated with high levels of serum SPan-1 antigen and CA19-9.

Somatostatin inhibits pancreatic exocrine secretion centrally via sympathetic nerves in conscious rats

Somatostatin is known to be a potent inhibitor of pancreatic exocrine secretion, but the mechanism of its effect is not fully understood. The mechanism of the inhibition by centrally administered somatostatin was examined in conscious rats. Rats were prepared with cannulae draining bile and pancreatic juice separately, and with a duodenal cannula, an extrajugular vein cannula and a cerebroventricular cannula. Somatostatin was injected into the left lateral ventricle, and the inhibitory mechanism was examined using vagotomized rats and various drugs that affect sympathetic neurons. Intracerebroventricular administration of somatostatin significantly inhibited pancreatic exocrine secretion stimulated by bile-pancreatic juice diversion. The inhibitory effect was not abolished by vagotomy, pretreatment with propranolol, but was abolished by pretreatment with hexamethonium or phentolamine. The plasma level of somatostatin after its intracerebroventricular administration increased 3-fold, but its intravenous infusion at a rate giving a similar plasma somatostatin level to that produced by its intracerebroventricular injection, had no significant effect on pancreatic secretion. These results suggest that somatostatin inhibits pancreatic exocrine secretion centrally via sympathetic efferent nerves and that alpha-adrenergic receptors have an important role in its inhibitory action.