Phenytoin-induced cerebral thrombosis in rats: cerebral ultrastructure, water content and ischaemic volume in the acute phase

A new rat model for multifocal cerebral thrombosis has recently been reported (Tani et al., 1994; 1995). Ultrastructural changes in the cerebral neocortex in the acute phase were investigated in order to characterize the early pathological events in this model. A bolus injection of alkaline phenytoin solution (pH 10.8) into one internal carotid artery in the rat caused severe endothelial injury accompanied by thrombosis in the cerebral vasculature within 5 minutes, and severe oedema of the ipsilateral hemisphere within an hour. Cerebral water content was measured by the simple dry-wet method, and cerebral surface area and the surface area and volume of the ischaemic zone were measured using computer-aided image analysis. Good correlations were demonstrated between cerebral water content and cerebral surface area, and between the surface area and volume of the ischaemic zone. We report here that quantitative evaluation of acute cerebral damage induced by phenytoin solution is possible with high reliability using simple image analysis.

[Acute subdural hematoma caused by professional boxing]

Knockout in boxing entails deliberate production of the state of unconsciousness. Acute subdural hematoma which is the most common acute brain injury in boxing, accounts for 75% of all acute brain injuries and is the leading cause of boxing fatalities. The aim of this study is to evaluate acute subdural hematoma caused by professional boxing by analyzing the content of bouts, the level of consciousness on admission, CT scan, therapy and outcome 3 months after admission. Fifteen boxers who had suffered from acute subdural hematoma were classified into three groups according to the pattern of loss of consciousness. Transient unconsciousness type (Transient type): boxers who had returned to alertness within an hour from the time of injury. Lucid interval type: neurological deterioration appeared with a lucid interval from ten minutes to an hour after knockout. Deterioration of consciousness type (Deterioration type): A state of unconsciousness appeared and worsened from a few minutes after knockout. Analyzing the number of rounds in bouts indicated that the hematoma occurred most frequently in bouts of 10 rounds. All of our subjects presented subdural hematomas without cerebral contusions on CT scan. With regard to the location of the hematomas, 9 hematomas involved the left side, 3 the right, 2 the suboccipit and 1 the interhemisphere. Transient type was found in 7 patients who had GCS scores of 14, 15 on admission. Since CT scan revealed thin subdural hematoma with or without mild midline shift, conservative therapy was carried out in all patients. All patients had a good recovery. Five patients of lucid interval type with an admission GCS score of 4, 6 and 7 demonstrated thicker hematoma compared to that presented by the transient type with significant midline shift on CT scan. All patients required surgery. Outcome of this type was good recovery (n = 2), moderate disability (n = 1), persistent vegetative state (n = 1), death (n = 1). Three patients of deterioration type had GCS scores of 5, 6. Because of subdural hematoma with remarkable midline shift on CT scan, all patients underwent surgery. Outcome was good recovery (n = 1), moderate disability (n = 1), persistent vegetative state (n = 1). Overall outcome was good recovery 66.7%, moderate disability 13.3%, persistent vegetative state 13.3%, death 6.7%. Furthermore, 8 patients who underwent surgery with a GCS score of less than 8 exhibited good recovery 37.5%, moderate disability 25%, persistent vegetative state 25%, death 12.5%. CT scan of lucid interval and deterioration type showed a tendency to show thick subdural hematoma and remarkable midline shift compared to transient type. Outcomes of lucid interval and deterioration type were worse than those of transient type. This result suggests that the influence of repeated head injury and diffuse brain injury might make a difference between these groups. Repeated head injury means that further impacts repeatedly damaged the injured brain after bleeding in the bouts. Overall outcome was better than that published in previous reports and also than that observed in other head injuries, for example, traffic accident and fall. The reasons for this could be that the patients were younger, that there was immediate surgical treatment, and that brain injury without cerebral contusion had contributed to better outcome. Finally, the best medical management intervention seems to be to diagnose and treat the lesions as early as possible after occurrence of subdural hematoma.

[Surgical treatment of syringomyelia]

Eighty cases of surgically treated syringomyelia were retrospectively reviewed. The cases were classified into following 4 types, type 1: syringomyelia with Chiari malformation (54 cases), type 2: syringomyelia with basal arachnoiditis (15 cases), type 3: syringomyelia with an obstruction of the foramen Magendie (1 case), and type 4: syringomyelia with spinal arachnoiditis (14 cases). Foramen magnum decompression (FMD) was performed in patients with type 1, in type 2 fourth ventricle-subarachnoid shunt was additionally performed. Gardner's operation was performed in patients with type 3. Syrinx-peritoneal shunt was performed in patients with type 4. Surgical procedures for syringomyelia which we selected were thought to be appropriate, based on postoperative syrinx collapse rate in MRI. However, postoperative clinical course was much different in each type of syringomyelia after the collapse of syrinx had been equally achieved. Neurological disorders were stopped in deterioration after surgery in all cases of type 1. However, motor weakness was still deteriorated in half cases of type 2, and in 60% of type 4. When clinical severity of the patients with type 1 and 2, based on the distribution of dissociated sensory loss and motor weakness, were classified into 5 grades. The rate of improvement of patient's symptoms and signs was higher in the lower grades. We concluded that a surgical treatment for syringomyelia was essentially a preventive one, therefore it should be done in early stage of disorders.

Induction of cerebral thrombosis with phenytoin in rats

BACKGROUND AND PURPOSE

This study was conducted to explore whether intra-arterial infusion of phenytoin causes cerebral ischemia and to examine the mechanism of cerebral ischemia induced by phenytoin.

METHODS

Ten rats were infused with phenytoin (150 microL, 3.75 mg) retrogradely from the left external carotid artery, followed by perfusion of carbon black transcardially. The removed brain was photographed from above, and the nonperfused area was compared with control rats (n = 10) with the use of an image analyzer. Eight animals with or without phenytoin treatment were perfusion-fixed for transmission electron microscopic analyses of cerebral vasculature. To determine the effect of tissue plasminogen activator (TPA) on phenytoin-infused rat cerebrum, 20 rats were treated with or without TPA (120,000 IU) 5 minutes after the phenytoin infusion (n = 10 each).

RESULTS

All rats suffered from respiratory distress 25 to 40 minutes after the injection and received carbon black transcardially. The nonperfused area was seen in the territory of the left internal carotid artery. Thrombi were observed from arterioles to capillaries. Under electron microscopy, endothelial cells were partially exfoliated, and the vascular lumen was obstructed by thrombi predominantly consisting of platelets. Eight rats with TPA survived more than 60 minutes, whereas only 2 rats survived without the treatment (P < .005). Nonperfused areas were 7 +/- 5% and 50 +/- 11% of cerebral surface area in rats with and without TPA treatment, respectively (P < .001).

CONCLUSIONS

Intra-arterial infusion of phenytoin results in a nonperfused area in rat cerebrum primarily due to thrombosis of arterioles and capillaries.

Chronic oral administration of synthetic trypsin inhibitor camostate reduces amylase release from isolated rat pancreatic acini

In the present study, we examined stimulus-secretion coupling in pancreatic acini prepared from rats given synthetic protease inhibitor camostate at a dose of 200 mg/kg body wt by an orogastric tube once a day for 10 d. Camostate treatment significantly increased pancreatic weight, protein, DNA, and enzyme contents. In acini prepared from the camostate-treated rats, responsiveness to both CCK-8 and carbamylcholine was greatly decreased with no shift in the dose-response curves compared to control acini prepared from saline-treated rats. There were no major changes in the affinity for both high- and low-affinity sites of CCK receptors, but there was a significant reduction in the capacity of low-affinity site based on acinar protein. Responsiveness to secretin in the camostate-treated rat acini was also significantly reduced compared with that in the controls. However, amylase release from the camostate-treated rat acini in response to an increase in intracellular calcium levels induced by the calcium ionophores A23187 or to an increase in intracellular cyclic 3',5'-monophosphate (cyclic AMP) levels caused by 8 bromo cyclic AMP was not significantly different from the control rat acini, suggesting that both Ca(2+)-dependent tyrosine kinase and nucleotide-activated kinases are not impaired. On the other hand, the responsiveness to phorbol ester TPA, which stimulates amylase secretion via a calcium-independent cascade by activating protein kinase C directly, was reduced in the camostate-treated rat acini compared with the controls. These results suggest the possibilities that the reduced amylase secretion in the camostate-treated rats is owing to alterations in both the transmembrane signal transduction and the phosphorylation of regulatory proteins by the Ca(2+)-independent, protein kinase C-dependent mechanisms.

Interaction among secretagogues on pepsinogen secretion from rat gastric chief cells

We examined the interaction among secretagogues that stimulate pepsinogen secretion through different pathways in vivo and in vitro. In in vitro study, a combined administration of secretin and carbachol or cholecystokinin octapeptide (CCK-8) to the culture medium of chief cells potentiated pepsinogen secretion. Moreover, the response induced by carbachol or CCK-8 with forskolin was greater than that with secretin. We examined the interaction among receptor-related second mediators, and found that carbachol- or CCK-8-induced intracellular Ca2+ concentration ([Ca2+]i) increase was not affected by secretin or forskolin. Both these substances, however, significantly reduced secretin-induced cAMP production. On the contrary, CCK-8 significantly increased forskolin-induced cAMP production, while carbachol increased it slightly. Calcium ionophore, A23187, or protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), did not alter secretin- or forskolin-induced cellular cAMP production; and the reductive effect of carbachol or CCK-8 on secretin-induced cAMP production was restored by their competitive antagonists, atropine or lorglumide. EC50 of those antagonists was almost the same value as IC50 on pepsinogen secretion and [Ca2+]i increase. These results indicate that secretin-induced cAMP production is interfered with by receptor related agonists like CCK-8 and carbachol. It may be suggested that there is a kind of "cross-talk," between the adenylate cyclase system, that is, the secretin receptor, and carbachol or CCK-8 receptor. The interactions between secretin and other secretagogues (carbachol, CCK-8, tetragastrin and histamine) were examined using the perfused rat stomach.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intra-and extracranial chondrosarcoma]

A 17-year-old female, who had diplopia and progressive gait disturbance, had been diagnosed as having a right parasellar mass lesion in 1986. Initial CT scan failed to show a parasellar space occupying lesion, although it was well demonstrated on MRI. No surgery was carried out at that time. Seven years later, she was hospitalized because of progressive gait disturbance, lower cranial nerves palsy, and cerebellar sign as well as the known right abducence palsy. At this time, CT scan exhibited a huge low density area with a marginal high density area suggesting calcification, which extended from the right parasellar area to the ventral portion of the midbrain. She underwent surgery under the diagnosis of cartilaginous tumor or chordoma. The intracranial lesion was removed via combined translabyrinthine approach and epidural subtemporal approach. The tumor was hitologically diagnosed as well-differentiated chondrosarcoma. Electron-microscopy demonstrated tumor cells with features of chondrocytes. Since the original site of the tumor, strategies for treatment and prognosis are different from each other, distinction between chondrosarcoma and chordoma is important. MRI seemed very useful for making this distinction as a first step.

The interaction of quinacrine with triple-stranded poly(U).poly(A).poly(U)

The interaction of the antimalarial drug quinacrine (QAC) with triple-stranded poly(U).poly(A).poly(U)(poly(U.A.U)) has been investigated by absorption, fluorescence and circular dichroism (CD) measurements. The results indicate that QAC binds to poly(U.A.U), as well as double-stranded poly (A).poly(U) (poly(A.U)) and poly(I).poly(C) (poly(I.C)). It is concluded that the acridine ring of QAC intercalates into successive U.A.U base-triplets from the minor groove, because the third-strand poly(U) in the major groove of poly(A.U) inhibits the binding of QAC to the major groove.

["Skip lesions" in neurological deficits caused by tethered cord syndrome]

The neurological deficits caused by tethered cord syndrome do not necessarily follow a dermatomal pattern of the affected spinal cord from caudal to cephalic fashion. The authors defined these neurological deficits as "skip lesions", and reviewed the neurological deficits in tethered cord syndrome. Among 29 cases, inconsecutive segmental motor weakness in 3 cases, inconsecutive segmental sensory impairment in 6 cases, positive Babinski reflex in 8 cases, supranuclear neurogenic bladder in 3 cases and lumbago or leg pain in 4 cases were observed and they were thought to be compatible with the neurological deficits called "skip lesions". The basic mechanism of this sign is that the cephalic portion of the spinal cord is functionally impaired during flexion of the lumbosacral spine, while the caudal spinal cord with decreased visco-elasticity dose not elongate. Inconsecutive motor-sensory disturbance, accelerated deep tendon reflexes in the lower extremities, positive Babinski or other pathological reflexes in the lower extremities, uninhibited neurogenic bladder, lumbago and pain in the legs were considered to belong to the category of "skip lesions" and they can be treated by the untethering procedure. The authors concluded that preoperative careful insight into the mechanism of "skip lesions" revealed surgical efficacy for the reversible neurological deficits by the untethering procedure, or the efficacy of decompression of the lipoma or neurolysis around the involved spinal nerve roots.

Secretion of intrinsic factor from cultured rat gastric chief cells

Intrinsic factor (IF) is a vitamin B12 binding protein that is secreted from the gastric mucosa. We tested secretagogues which stimulate IF secretion in rat gastric perfusion and found that carbachol and cholecystokinin octapeptide (CCK-8) stimulated secretion, but histamine and tetragastrin did not. To confirm these results, we examined IF secretion from isolated rat chief cells. For this purpose, we established an enzyme immunoassay (EIA) using an avidin-biotin peroxidase complex to measure small amounts of IF. To prepare an anti-rat IF, IF was isolated from the stomach, and was injected into a rabbit for immunization. Rat gastric chief cells were isolated from the gastric mucosa with Dispase and a Percoll gradient centrifugation, and were cultured. We examined the effects of chemicals by adding them to culture dishes of chief cells in a CO2 incubator. Released IF in culture medium was determined by EIA. Carbachol, CCK-8 and secretin stimulated IF secretion from cultured chief cells, while histamine and tetragastrin did not; Forskolin and A23187 also stimulated the secretion. We concluded that carbachol and CCK-8 stimulated IF secretion via an increase of intracellular Ca2+ concentration and that secretin did so via a cAMP accumulation.

Inhibitory action of somatostatin on cAMP dependent pepsinogen secretion from rat gastric chief cells: involvement of pertussis toxin-sensitive G-protein

We examined the inhibitory effect of somatostatin on pepsinogen secretion using isolated rat gastric chief cells. Secretin and forskolin significantly increased not only pepsinogen secretion from chief cells but also cellular cAMP accumulation in a dose-dependent fashion. Somatostatin significantly inhibited secretin- and forskolin-induced pepsinogen secretion and secretin-induced cellular cAMP accumulation. However, forskolin-induced cellular cAMP accumulation was not inhibited by somatostatin. The inhibitory effect of somatostatin on secretin-induced pepsinogen secretion was abolished by pretreatment with pertussis toxin, but inhibition of forskolin-, carbachol- and cholecystokinin octapeptide-induced pepsinogen secretion was not. These results suggest that somatostatin inhibits pepsinogen secretion in two ways, one is closely related to the pertussis toxin-sensitive G-protein and the other is not determined.

[Evaluation of serum enzyme levels considering biological half lives of enzymes--alteration of lactate dehydrogenase isoenzyme pattern due to computer simulation]

The rapid clearance of certain releasing enzymes from blood stream may modify their usefulness as markers of disease. Serum LD isoenzyme patterns are often quite different from those in the affected tissues. Such differences result from differences in the biological half lives of the individual isoenzyme. In order to reveal such phenomena, we applied the one-compartment model to simulate the time dependent changes in the serum LD isoenzyme patterns as a most simple model. When we simulated leukemic cells as an affected origin, LD isoenzyme patterns obtained at a stage of clinical deterioration or active stage, were characterized by a high proportion of LD-2, LD-3 and LD-4, and resembled those of the original leukemic cells. In general, strong similarities in alterations of LD isoenzyme patterns were obtained between the clinical observed time course and simulated time course. These changes in LD isoenzyme patterns are practically observed in the cases of leukemia, lymphoma, and so on. If the original organs are identical, then it is change of disease stage that is responsible for modification of variable LD isoenzyme patterns. Such phenomena must therefore be noted--in doing so, we shall be able to estimate the origin of enzyme release, disease stage, and prognosis.

Differential effects of proteinase inhibitor camostat on exocrine pancreas in fed and fasted rats

Effects of an oral dose of the synthetic trypsin inhibitor camostat on pancreatic exocrine function were examined in rats that were either fasted from 12 h before feeding camostat to the end of experiments or fed ad libitum. Camostat (100 mg/kg body wt) caused significant increases in plasma cholecystokinin bioactivity (peak 13.4 +/- 2.0 pM at 30 min for fasted rats vs. 16.6 +/- 1.7 pM at 2 h for fed rats; not significant) and pancreatic exocrine secretion. In fed rats, but not in fasted rats, significant increases in pancreatic exocrine secretion were observed again at 12 h after a single oral dose of camostat (juice flow 10.3 +/- 0.4 microliters/20 min in fasted rats vs. 175.5 +/- 17.8 microliters/20 min in fed rats; P < 0.001), although pancreatic juice flow in fed and fasted control rats was nearly the same. When the pancreata from camostat-pretreated rats were isolated and perfused, the early effects of camostat on pancreatic exocrine secretion were abolished, whereas the late effects (12 h postfeeding) in fed rats were still observed (juice flow 33.7 +/- 3.4 microliters/20 min vs. control 2.8 +/- 0.4 microliters/20 min; P < 0.001). Thus, in addition to humoral and neural factors, persistent functional changes might have occurred in the pancreas of the fed camostat-pretreated rats. These present results indicate that oral camostat induces two different effects, immediate and delayed, on pancreatic exocrine secretory function. Camostat exerts its immediate effects in both fed and fasted rats, whereas delayed effects were induced only in fed rats.

[Evaluation of the postoperative regrowth of the acoustic neurinomas]

Although recent advances in microsurgical removal of acoustic neurinomas has made it possible to preserve, morphologically, the cochlear nerve as well as the facial nerve, functional impairment of the facial nerve is often encountered following total removal of the tumor. In order to avoid such functional morbidity, a surgical procedure can be proposed in which the tumoral capsule attached to a functional structure such as the facial nerve is intentionally left. Along with this surgical procedure and postoperative course observation, postoperative regrowth of the tumor should be precisely evaluated. A few recent reports about this problem have been published since CT scan and MRI have become available. The authors reviewed 66 cases in which postoperative evaluation by high resolution CT scan of the acoustic neurinomas has been carried out in their department more than one year after surgery. Multiple factors such as age at onset, sex, preoperative period, tumor size, vascularity, extent of the tumor removal, residual site, and pathological findings on HE stain were studied in relation to the tumor regrowth. Four cases showed regrowth of the tumor, and one of these tumors was reoperated on. The percentage of regrowth was 7.5% among the tumors which were not totally removed. No significant risk factors for tumor regrowth were noticed in these cases, but tumor regrowth tended to be found in younger patients. The residual tumors which showed regrowth were always located in the internal auditory meatus. In this study, it is apparent that, percentagewise, tumor regrowth is not so prevalent.(ABSTRACT TRUNCATED AT 250 WORDS)

[A meningioma in the posterior fossa without dural attachment: case report]

An extremely rare case of a meningioma in the posterior fossa without dural attachment has been reported. The patient was a 56-year-old male whose chief manifestation was the abnormality of his CT scan. His past history included gastric and colonic polyp when he was 54, 55 years old, and non-Hodgkin's lymphoma before hospitalization in our department. CT scan showed a small round non-enhancing lesion located at the lateral site of the right cerebellar cortex. T1 weighted image of MRI showed a homogeneous low intensity lesion with partial enhancing with Gd-DTPA. Proton image showed a remarkable low intensity lesion which showed an extramedullary mass. Right retromastoid craniectomy was performed. The mass was an extramedullary tumor which had no relation with the cerebellar cortex and dura matter. The arachnoid membrane around the tumor was intact. The tumor was totally resected and the patient had no neurological deficits. Histopathologically, the tumor was delineated into laminar structures by collagen fiber. Tumor cells were spindle in shape and made a whorling formation. There was no psammoma body and it had a hyperchromatic nuclei without mitotic features. Electron microscopic studies revealed no typical interdigitation but irregularity of the cell membrane. Abundant collagen fibers were in contact with basement membrane of the tumor. According to these findings, we diagnosed fibroblastic meningioma with atypical forms. Meningiomas without dural attachment are rare in adults, especially extremely rare of the posterior fossa. There are only 23 previous reports of "meningioma of the posterior fossa without dural attachment". Cantore divided these meningiomas into three groups (IV ventricle, inferior tela choroidea and cisterna magna).(ABSTRACT TRUNCATED AT 250 WORDS)

Somatostatin inhibits pepsinogen secretion without influencing cytosolic free Ca2+ increase induced by carbachol and cholecystokinin octapeptide in rat chief cells

Gastric chief cells were isolated from the rat stomach in an attempt to identify those involved in the mechanism of action of somatostatin on pepsinogen secretion. The effects of several kinds of secretagogues on cytosolic free Ca2+ concentration ([Ca2+]i) were examined in the rat chief cells. Carbachol and cholecystokinin octapeptide (CCK-8) markedly induced [Ca2+]i increase, while histamine, gastrin I and secretin did not. Carbachol and CCK-8 also stimulated pepsinogen secretion. A similar dose-response relationship was seen in carbachol- and CCK-8-induced [Ca2+]i increase and pepsinogen secretion. Somatostatin did not inhibit carbachol- or CCK-8-induced [Ca2+]i increase, but did inhibit carbachol- and CCK-8-induced pepsinogen secretion by 30 and 50%, respectively.

[Analysis of water content in young rats brain edema by Raman spectroscopy]

Cerebral edema, classified into vasogenic edema and cytotoxic edema, has long been studied and recognized to be complicated. The authors studied the cerebral edema models of young rats suffered from cryo-injury and triethyl tin chloride (TET) injury by Raman spectroscopy which can physiologically evaluate the cerebral water content (%) of very restricted area. The cryo-injury model was conducted in the following manner. A cryo-probe (-196 degrees C) was contacted to the exposed cranium for 20 seconds in an anesthetized 4-5-week-old Sprague-Dawley young rat. A coronal section of the injured brain covered with a slide glass and wrapped by Parafilm was obtained 2, 4, 6, 8, 12, 24, 48, 72 hours after the cryo-injury in order to measure the water content by Raman spectroscopy employed by Tashibu and Huizinga. TET injury model was obtained by intraperitoneal administration of TET (4.5 mg/Kg). The water content was observed by the same manner as for the cryo-injury model. Subsequent to the cryo-injury, the water content of the white matter which seemed to be higher than in adult rats increased rapidly and persisted in the same condition within 72 hours. Subsequent to TET injury, the water content of the white matter increased more rapidly than that of the gray matter, however, in adult rats the water content of the gray matter showed more rapid increase than that of the white matter. Increased water content followed by TET injury was higher in adult rats than in young rats.(ABSTRACT TRUNCATED AT 250 WORDS)

An ab initio molecular orbital study on effect of electric field strength on ionic selectivity of the sodium channel

The effect of electric field strength of the selectivity filter on ionic selectivity of the sodium channel has been studied by ab initio molecular orbital calculations. On the basis of the previous method, two kinds of model systems, the FCO2M system and the FCO2M-H2O system, were studied. In this study, a FCO2- molecule, which is substituted for a HCO2- molecule, was used as a model for the selectivity filter. This substitution corresponds to weakening the electric field strength of the selectivity filter. For this system, geometries of ground and transition states were optimized with MINI-3 basis sets. The FCO2-H2O system, for which we evaluated thermochemical parameters and cross-sections, is a good model for ionic permeation of the sodium channel. When the results of the FCO2M-H2O system were compared with those of the HCO2M-H2O system, we concluded that permeabilities of Li+ and Na+ are smaller and that of K+ is larger as the field strength of the selectivity filter is weakened. Namely, the permeation of K+ is relatively favorable when the field strength of the selectivity filter is weakened. This conclusion is in accordance with the prediction of Eisenman's theory.

A microneutralization enzyme immunoassay for antibody to human cytomegalovirus

We have developed a relatively rapid, sensitive and quantitative microneutralization assay for antibody to human cytomegalovirus (HCMV). Cell monolayers in 96-well microtiter plates inoculated with pre-incubated virus-antibody mixtures were fixed after 3 days. Infectious foci were stained with peroxidase-labeled human monoclonal antibody to a 64 kDa immediate early antigen of HCMV, and the plates were read at OD450. The 50% neutralization titer of the antibody was calculated. A study with 20 human sera and a human monoclonal antibody which neutralizes virus showed that this microneutralization enzyme immunoassay is more sensitive than, and as quantitative as, the conventional plaque reduction assay for antibody to HCMV. The neutralizing antibody titers of each sample measured by these two methods showed good correlation (n = 19, r = 0.884). Thus, this new assay is a useful and valid alternative to the conventional method for mass screening of sera and hybridoma fluids, and considerably more rapid.

[Plasma cholecystokinin levels in rats with pancreatic insufficiency induced by intra ductal injection of oleic acid]

Plasma cholecystokinin (CCK) levels in rats with pancreatic insufficiency induced by a single injection of 50 microliters oleic acid into the pancreatic duct were determined by a sensitive and specific bioassay using the isolated rat pancreatic acini. Treatment with oleic acid significantly decreased pancreatic wet weight within 7 days, which lasted until the end of observation (56 days). Histologic examination revealed the destruction of acinar cells and the epithelium of intra- and interlobular ducts. Plasma CCK bioactivity was significantly increased from the pre-treatment values of 0.8 +/- 0.1pM to 5.1 +/- 1.4pM at 24h after oleic acid treatment. After this peak, plasma CCK levels gradually decreased. Even after 56 days, however, plasma CCK levels in oleic acid-treated rats were significantly high compared with those in control rats. In the present study, plasma CCK levels in rats with chronic pancreatitis did not correlate with the progress of pancreatic insufficiency.

Involvement of endogenous cholecystokinin in the development of acute pancreatitis induced by closed duodenal loop

Involvement of endogenous cholecystokinin (CCK) in the development of acute pancreatitis induced in rats by closed duodenal loop (CDL) was examined, and the effects of the potent and specific CCK receptor antagonist loxiglumide on this model of acute pancreatitis were evaluated. Plasma CCK bioactivity was markedly elevated 3 and 6 h after onset of acute pancreatitis. A single subcutaneous injection of 50 mg/kg body wt of loxiglumide 30 min before the induction of acute pancreatitis completely eliminated the hypercholecystokinemia. Loxiglumide given 3 h after the induction of acute pancreatitis suppressed plasma CCK bioactivity, which had risen up to 30-fold over basal value (0 h) at 3 h, to nearly the basal level. Loxiglumide pretreatment, in addition, significantly prevented the rise in serum amylase and lipase activity, as well as the increase in ascitic volume. It also ameliorated histological alterations of hemorrhagic and necrotizing pancreatitis. Reduction of plasma CCK bioactivity by loxiglumide after the onset of pancreatitis slowed the rate of progression of pancreatitis. However, pancreatic wet weight and cellular infiltration were not significantly influenced by loxiglumide treatment. These observations suggest that endogenous CCK is not involved in the initiation of acute hemorrhagic and necrotizing pancreatitis induced by CDL, but is involved in the development of pancreatitis in this model.

[Inhibitory effect of somatostatin analog, SMS 201-995, on exocrine secretion from isolated rat pancreatic acini]

In vitro effect of somatostatin analog, SMS 201-995 (SMS), on pancreatic exocrine secretion was investigated using isolated rat pancreatic acini. SMS had no effect on basal, cholecystokinin octapeptide (CCK-8)- or secretin-stimulated amylase release. SMS inhibited pancreatic amylase release in response to simultaneous stimulation with secretin and CCK-8 in a dose-dependent manner. Significant inhibition was observed with 10 nM SMS and maximal inhibition with 0.1-1 microM SMS. Amylase release in response to the combination of 100 pM CCK-8, 1 nM secretin and 0.1-1 microM SMS was similar to that to 100 pM CCK-8 alone. Secretin significantly increased acinar cell cAMP content. SMS partially inhibited an increase in cAMP content induced by secretin. The present study has demonstrated, therefore, that SMS directly inhibits the potentiating effect of secretin on exocrine secretion in part by inhibiting an increase in secretin-induced cAMP accumulation in rat pancreatic acinar cells.

Primary cardiac hemangiopericytoma causing rupture of the right atrium and chronic cardiac tamponade

A 53-year-old woman presented with symptoms of dyspnea on exertion and edema of lower extremities. Chronic cardiac tamponade caused by the rupture of the right atrial wall was diagnosed by two-dimensional contrast echocardiography. Autopsy findings revealed primary cardiac hemangiopericytoma.

[Changes in lumbosacral canal length during flexion and extension--dynamic effect on the elongated spinal cord in the tethered spinal cord]

This clinical research has been conducted to extend the understanding of pathophysiological mechanism involved in the tethered cord syndrome. In normal individuals, the filum terminale has elasticity similar to the rubber band. This allows cephalad or caudad movement of the lumbosacrococcygeal spinal cord while the spine is flexed or extended. This is based on the observation that the lowest pair of dentate ligaments spans from the T12 and L1 junction of cord segments to the dura between the dural exit of T12 and L1 nerve roots, and the spinal cord below T12 can freely ascends on flexion and descends in the spinal canal on extension of the spine. In 50 healthy human subjects, x-ray films of the thoracolumbosacral spine were studied. Lateral films of the spine were taken in the neutral, hyperextended and hyperflexed positions. The first group included 10 individuals whose ages ranged from 27 to 42 years. The distance between the middle of the T10 vertebra and L1-L2 interspace was measured. This distance was considered to represent the length of the lumbosacral cord segment (L1 through coccygeal cord segments). The second group included 40 individuals whose ages ranged from 17 to 50 years. The distance between the L1-L2 interspace and S1-S2 interspace was measured. The distance signified the distance between the caudal end of the spinal cord and attachment of filum terminale to the sacrum. There was a 3.5% (4.6mm by X-ray films) increase during hyperflexion in the distance measured in the first study.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ethanol on pancreatic exocrine secretion in rats

The effect of ethanol on pancreatic exocrine secretion was studied in isolated rat pancreatic acini. Ethanol caused a dose-dependent stimulation of amylase release, and a twofold increase of amylase release was observed with 600 mM ethanol. Ethanol inhibited cholecystokinin octapeptide (CCK-8)- and carbamylcholine-stimulated amylase release and similarly inhibited binding of [125I]CCK-8 and [N-methyl-3H]scopolamine to isolated rat pancreatic acini in a dose-dependent manner. The inhibitory effect of ethanol was fully reversible with respect to CCK-8-induced amylase release. On the other hand, ethanol potentiated secretin- and vasoactive intestinal peptide (VIP)-stimulated amylase release. Ethanol induced a small but significant increase in Ca2+ efflux, whereas CCK-8 induced an immediate and large increase, but ethanol significantly inhibited CCK-8-stimulated Ca2+ efflux. The present study clearly demonstrates the dual effects of ethanol on pancreatic exocrine function: stimulation and inhibition. We suggest that mobilization of intracellular Ca2+ may be involved in the mechanism of ethanol's action on isolated rat pancreatic acini.

Preliminary X-ray crystallographic analysis of tryptophanase from Escherichia coli

Tryptophanase (L-tryptophan indole-lyase) from Escherichia coli has been crystallized from ammonium sulfate solution using a vapor diffusion method. The crystals are tetragonal and belong to space group P4(1)2(1)2 or its enantiomorph. The cell dimensions of the crystals are a = b = 113.4 A, and c = 232.2 A, with two subunits per asymmetric unit. The crystals diffract to at least 3 A resolution, and are suitable for X-ray structural analysis.

A case of cardiac amyloidosis presenting with symptoms of exertional syncope

A 54-year-old man presented with symptoms of exertional syncope. Cardiac amyloidosis was diagnosed by endomyocardial biopsy. Exercise tolerance test revealed a failure of increased heart rate followed by sinus arrest, associated with syncope. Autopsy revealed amyloid deposits in the sinoatrial node.

Enzymatic degradation of helodermin and vasoactive intestinal polypeptide

Helodermin (HDM) belongs to the vasoactive intestinal polypeptide (VIP) family of polypeptides. Degradation of HDM in the tracheal tissue isolated from a guinea-pig and by an isolated enkephalinase was studied and compared with the degradation of VIP. The tracheal relaxing activity of VIP was potentiated by enkephalinase inhibitors, thiorphan and phosphoramidon, while the activity of HDM was not potentiated. On the other hand, bestatin, an aminopeptidase inhibitor, and captopril, an angiotensin converting enzyme inhibitor, did not influence the activity of VIP and HDM. The data suggests that the degradation of VIP but not HDM in the trachea was done by enkephalinase. Enkephalinase was then purified from the lung and the striatum membrane fraction through a DEAE-cellulose column, chromatofocusing column and hydroxyapatite column. The purified enkephalinase from the lung hydrolyzed VIP but not HDM. HDM and VIP were, however, hydrolyzed by the striatum enkephalinase. There was only a partial degradation of HDM by the striatum enkephalinase and the hydrolysis rate of HDM was slower than that of VIP. The degradation of VIP and HDM was inhibited by thiorphan. In conclusion, we found that VIP but not HDM was degraded by enkephalinase present in the respiratory system such as the trachea and the lung. Furthermore, enkephalinase, which hydrolyses HDM, was present in the brain.

[A case of pseudo-TSH.PRL-producing pituitary adenoma with secondary hypothyroidism]

A 24-year-old housewife presented with weight gain of about 30 kg, constipation and pitting edema of extremity nine years after having a thyroidectomy. Hormonal examination revealed low levels of serum T3 and T4 and high levels of serum TSH and PRL. She also had enlarged pituitary gland (pituitary hyperplasia) with suprasellar extension on CT and MRI image. Thyroid replacement therapy and follow-up by MRI were performed without resort to surgery, because she had no visual disturbance. Within about 1 month after thyroid replacement therapy, serum TSH and PRL were normalized. And also thyroid function was normalized by thyronine (T3). Following this results, pituitary hyperplasia regression was seen on MRI image. About 1 year after thyroid replacement therapy, pituitary hyperplasia regression was more seen on MRI image. Prolonged hypothyroidism can result in hypertrophy of the pituitary thyrotropin-secreting cells and prolactin secreting cells. So, it can increase pituitary weight (pituitary hyperplasia). Radiological examination, abnormal sellar x-ray films suggesting intrasellar tumor are common in patients with primary hypothyroidism. Suprasellar extension of pituitary mass (pituitary hyperplasia) due to hypothyroidism was reported by radiological examination (PEG, CT and MRI image), and regression of pituitary hyperplasia was revealed by radiological examination after thyroid replacement therapy. The first choice of this type of pituitary hyperplasia is thyroid replacement therapy unless the patient has a visual disturbance. However, if this replacement therapy is not effective for diminution of the tumor, surgical removal of the tumor should be considered.

Apodemus sylvaticus, a new host for Acanthocheilonema viteae (Nematoda: filarioidea)

Susceptibility of Apodemus sylvaticus and A. agrarius to infection with Acanthocheilonema viteae was compared with that of hamsters and jirds. Microfilaremia in A. sylvaticus was first noted on day 52 post-infection (p.i.) and lasted during the course of the study (up to day 150 p.i.). Maximum microfilaremic levels (female worm basis) of A. sylvaticus [mean +/- S.D. (n) = 690 +/- 1288(6)] were considerably higher than those of hamsters [16 +/- 18(6)] and jirds [51 +/- 25(5)]. Adult worm recovery in A. sylvaticus ranged from 2 to 40% of the number of infective larvae inoculated. Worm development in A. sylvaticus resembled that in hamsters and jirds. In contrast, microfilaremia was not detected in, nor adult worms recovered from A. agrarius throughout the study.

[A case of solitary syringobulbia]

A case of solitary syringobulbia without syringomyelia diagnosed by MRI was reported. A 63-year-old female, who had a history of progressive gait disturbance for 9 months, was admitted to our department because of severe headache. Neurological examination revealed that the patient was suffering from right pyramidal sign as well as left deep sensory disturbance without apparent impairment of cranial nerves or nystagmus. The somatosensory evoked potential stimulated by the left median nerve showed delay in latency and low amplitude, however, the auditory brainstem response showed normal records bilaterally. A syringobulbia associated with platybasia, basilar impression, obstructive hydrocephalus and Arnold-Chiari malformation was diagnosed by the neuroradiological examinations including plain X-ray films of the skull, CT scan and MRI of the brain. Subsequent to the decompression around the cisterna magna by suboccipital craniectomy and laminectomy of the atlas, the opening of the Foramen Monro which was obstructed by a thick membrane was carried out, and prevention of communication between the fourth ventricle and the syrinx was accomplished by using a piece of muscle. This operative procedure was thought to be compatible with Gardner's operation for syringomyelia. The patient showed gradual improvement of gait disturbance as well as headache 3 months after surgery, and this neurological improvement was proved by decrease in the size of the known syringobulbia on MRI, and by normalized somatosensory evoked potential stimulated by the median nerve. Pathophysiology of the solitary syringobulbia with relatively acute onset of the neurological symptoms was assumed to have taken place in the following manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of tryptophan 248 in the active site of tryptophanase from Escherichia coli

Tryptophan 248, located in the active site of tryptophanase from Escherichia coli, has been replaced with phenylalanine by site-directed mutagenesis. Judging from CD and fluorescence spectra, the global structure of the mutant enzyme was found to be the same as that of the wild-type enzyme. The binding affinity of the mutant enzyme for the coenzyme pyridoxal 5'-phosphate (PLP) was reduced tenfold compared to the wild-type enzyme. Kinetic analyses under PLP-saturated conditions indicated that the Km values of the mutant enzyme for substrates are the same as those of wild-type enzyme but the kcat values are decreased to about 85%, which accounts for the overall activity decrease. These findings suggest that tryptophan 248 interacts closely with PLP and plays an important role in the catalytic reaction.

Plasma atrial natriuretic peptide in young normotensive subjects with a family history of hypertension and in young hypertensive patients

Plasma atrial natriuretic peptide (ANP) behavior was evaluated in 26 untreated essential hypertensives, 21 normotensives, and 20 normotensives with hypertensive heredity under normal sodium intake (120 mEq of Na+/day). All subjects were men, mean age 22.1 +/- 1.9 years. Plasma ANP was evaluated by radioimmunoassay on samples collected in supine position upon waking and again after 1 h of orthostatism. Resulting data showed that ANP in hypertensives (supine = 44.5 +/- 19.4 pg/mL, orthostatism = 24.1 +/- 11.6 pg/mL) was at higher levels than in controls (supine = 38.3 +/- 19.4 pg/mL, orthostatism = 19.9 +/- 10.6 pg/mL) or in normotensives with hypertensive heredity (supine = 42.1 +/- 16.8 pg/mL, orthostatism = 23.2 +/- 10.8 pg/mL). Mean ANP level was higher in the latter group than in the control group (supine = +9%; orthostatism = +14.2%). In conclusion, plasma ANP is raised in young essential hypertensives, resulting in slightly elevated levels in normotensives with hypertensive heredity.

Direct inhibition of pepsinogen secretion from rat gastric chief cells by somatostatin

Effects of somatostatin on pepsinogen secretion was investigated in the rat in vivo and in vitro. In the perfused rat stomach, somatostatin inhibited secretagogue-induced acid secretion in dose-dependent manner. However, effects of somatostatin on secretagogue-induced pepsinogen secretion were obscure. To clarify the effects of somatostatin on the chief cells, gastric mucosal cells were isolated by a proteolytic enzyme. Somatostatin inhibited carbachol- and cholecystokinin octapeptide-induced pepsinogen secretion from dispersed gastric mucosal cells in a dose-dependent manner. Histamine-induced pepsinogen secretion, which was recovered by culturing, was also inhibited by somatostatin. These results suggest that somatostatin inhibits secretagogue-induced pepsinogen secretion directly.

[Spread of surgical indication for hepatoma with postoperative transcatheter arterial infusion]

We evaluated the reduction surgery and the postoperative TAI for unresectable hepato-cellular carcinoma (HCC). Eight patients underwent reduction surgery and postoperative TAI (group I). Twenty-five patients underwent combination therapy with TAI, TAE, EI, hyperthermia and irradiation, who had not undergone reduction surgery (group II). Nine patients underwent a relative noncurative operation (group III). We studied the prognosis of these three groups.

RESULTS

The one-year survival rates were 85.7% in group I, 38.6% in group II and 55.5% in group III. The three-year survival rates were 42.9% in group I, 10.7% in group II and 55.5% in group III. There was a significant difference of prognosis between group I and group II (p less than 0.05, generalized Wilcoxon). These results suggest that reduction surgery and post operative TAI for unresectable HCC improve the prognosis.

Fasting prevents acute pancreatitis induced by cerulein in rats

We examined the effect of fasting on the course of experimental acute pancreatitis induced in rats by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals. Rats were either fasted from 24 hr before to 9 hr after the first cerulein injection or fed ad libitum throughout the experiment. Twenty-four hours of fasting reduced cerulein-induced increases in serum levels of amylase and anionic trypsin(ogen) to 50 and 70% of those in fed rats, respectively. Increases in pancreatic wet weight after cerulein injections were also less in fasted rats than in fed rats. Pancreatic content of trypsin was significantly decreased after a 24-hr fast, and no further changes were induced by cerulein injections. The histological signs of acute pancreatitis were greatly alleviated by fasting. However, 24 hr of fasting did not alter the sensitivity and responsiveness of the exocrine pancreas to cerulein in both in vivo and in vitro. Plasma CCK bioactivity and immunoreactive secretin concentration in 24-hr-fasted rats were significantly lower than those in fed rats. Administration of CCK receptor antagonist, loxiglumide, 12 hr prior to the induction of acute pancreatitis reduced the increase in serum amylase activity in fed rats to nearly the same levels as that in fasted rats and alleviated histological signs of pancreatitis to some extent. These present observations suggest that fasting lessens the severity of cerulein-induced acute pancreatitis by reducing endogenous CCK release.

Action of a new cholinergic agonist, aclatonium napadisilate, on isolated rat pancreatic acini

The effect of aclatonium napadisilate, a newly synthesized choline ester, on pancreatic exocrine function was compared with that of the muscarinic agonist carbamylcholine in isolated rat pancreatic acini. Both compounds increased amylase release and 45Ca2+ efflux in a dose-dependent fashion, and similarly decreased the binding of [N-methyl-3H]scopolamine to isolated rat pancreatic acini. While aclatonium napadisilate was 20-30 times less potent than carbamylcholine in stimulations of amylase release and 45Ca2+ efflux, the potency of aclatonium napadisilate in inhibiting [N-methyl-3H]scopolamine binding was nearly the same as that of carbamylcholine. These results indicate that aclatonium napadisilate stimulates pancreatic exocrine secretion via muscarinic receptors and Ca2+ mobilization, and its intrinsic activity is less than carbamylcholine in the isolated rat pancreatic acini. Since aclatonium napadisilate is known to increase motility and peristalsis of the gastrointestinal tract, stimulatory effects of aclatonium napadisilate, shown in the present study, on digestive enzyme secretion from the pancreas may provide additional benefit of aclatonium napadisilate in the treatment of various gastrointestinal disorders.

Effect of a new cholecystokinin receptor antagonist loxiglumide on acute pancreatitis in two experimental animal models

We evaluated the effects of a new cholecystokinin (CCK) receptor antagonist, loxiglumide, in a model of mild pancreatitis induced by repeated injections of cerulein and in a severe necrotizing form of pancreatitis induced by retrograde ductal injection of sodium taurocholate (NaTc) in rats. A single subcutaneous injection or oral administration of 50 mg/kg of body weight of loxiglumide almost completely reduced the increases of serum amylase activity and pancreatic wet weight, and caused histologic improvements of the cerulein-induced acute pancreatitis when given 30 min before the first cerulein injection. Loxiglumide was also effective in reducing the elevated serum amylase activity, pancreatic wet weight, and histologic alterations even when administered after the induction of acute pancreatitis. However, loxiglumide offered no apparent beneficial effects when given 30 min before and 3 h after the induction of acute pancreatitis by NaTc as determined by changes in serum amylase activity, pancreatic wet weight, and histology. These results do not necessarily suggest that CCK is not important in the pathogenesis of pancreatitis, but do suggest that the sole blockade of peripheral CCK receptors is ineffective against NaTc-induced severe necrotizing pancreatitis.

Effect of Gymnema sylvestre, R.Br. on glucose homeostasis in rats

Effect of Gymnema sylvestre, R.Br. (G. sylvestre; GS4) on glucose homeostasis was studied in rats. In the first set of experiments, the acute effect of GS4 was examined in both non-diabetic and streptozocin (30 mg/kg)-induced mildly diabetic rats. Administration of 1 g/kg body weight of GS4 to 18-h fasted non-diabetic rats significantly attenuated the serum glucose response to oral administration of 1 g/kg glucose. The immunoreactive insulin (IRI) response in GS4-administered rats was lower, but not significantly, than that in control rats. In mildly diabetic rats, a 60 min increment in serum glucose concentrations was significantly reduced by GS4 administration. No IRI response was observed in these diabetic rats irrespective of GS4 administration. In the second set of experiments, the chronic effect of GS4 was examined in mildly diabetic rats. Two weeks after the induction of diabetes, the rats were divided into two groups that had similar impairment of glucose tolerance assessed by an oral glucose loading test. The rats were fed for 32-35 days with either a control diet or a diet supplemented with GS4. After 4 weeks, GS4 showed a tendency to reduce the serum glucose concentrations in the fed state and to improve the glucose tolerance. Gain in body weight, food intake, pancreas weight and the pancreatic contents of IRI, protein, amylase and trypsinogen were unaltered in the GS4-treated group compared with the control. These results suggest the usefulness of G. sylvestre in the treatment of certain classes of non-insulin-dependent diabetes mellitus.

Proglumide analogues CR 1409 and CR 1392 inhibit cholecystokinin-stimulated insulin release more potently than exocrine secretion from the isolated perfused rat pancreas

The effects of proglumide-related cholecystokinin (CCK) receptor antagonists CR 1409 and CR 1392 on CCK-octapeptide (CCK-8)-stimulated immunoreactive insulin (IRI) release and exocrine secretion were examined simultaneously in the isolated perfused rat pancreas. The CR 1409, at concentrations of 10-100 nM, significantly inhibited CCK-8 (100 pM) stimulation on IRI release but failed to inhibit the stimulatory effect of CCK-8 on both pancreatic juice flow and protein secretion. Increasing concentrations of CR 1409 inhibited both CCK-8-stimulated IRI release and exocrine secretion. Half-maximal inhibition was observed with approximately 2 nM for IRI release and 1 microM for protein secretion. When a higher dose (1 nM) of CCK-8 was used, the inhibitory effect of 10 nM CR 1409 on CCK-8-stimulated IRI release was abolished, whereas 10 microM CR 1409 retained significant inhibitory effect. Furthermore, 1 microM carbachol-induced IRI release was not altered by the addition of 10 microM CR 1409. The CR 1392 also had an inhibitory effect on both CCK-8-stimulated IRI release and exocrine secretion. The concentration of CR 1392 that caused half-maximal inhibition of CCK-8-stimulated IRI release was 300 times lower than that of exocrine secretion. In addition, 1 microM carbachol-stimulated IRI release was not altered by 100 microM CR 1392. Thus, the inhibitory effects of CR 1409 and CR 1392 on IRI release were mediated through the interaction at the CCK receptor and were more potent than those on juice and protein secretion. This study suggests, therefore, that CCK receptors on B cells might be different from those on acinar cells in terms of their relative affinities for antagonists.

Enzyme immunoassay for human pancreatic amylase

An enzyme immunoassay (EIA) for human pancreatic amylase has been developed for the detection of human serum amylase content. Our monoclonal antibody is highly specific for human pancreatic amylase; it cross reacted negligibly with the salivary isoenzyme. We developed a solid phase enzyme immunoassay for determination of pancreatic amylase in human serum with this antibody. The assay required 20 microL of serum and the standard curve was linear to at least 1000 ng/mL of pancreatic amylase. Inter- and intra-assay CVs were less than 10%. The results obtained by the EIA correlated well with those determined by the conventional electrophoretic method. In normal subjects, the mean concentration of serum pancreatic amylase determined by the EIA was found to be 92.3 +/- 26.1 ng/mL (mean +/- SD). The EIA we describe is useful for directly determining pancreatic amylase in human serum. Specifically distinguishing pancreatic from salivary amylase may have considerable clinical value.

Effects of L-364,718 on pancreatic exocrine and endocrine secretion in the rat

We examined the inhibitory effect of L-364,718, a nonpeptide cholecystokinin (CCK) antagonist, on CCK stimulation of pancreatic exocrine and endocrine secretion in both the isolated pancreatic acini and the isolated perfused pancreata of rats. In the isolated acini, L-364,718 inhibited CCK octapeptide (CCK-8)-stimulated amylase release and binding of 125I-CCK-8 in a dose-dependent manner without appreciable effects on the basal amylase secretion. L-364,718 also inhibited amylase release in response to caerulein and gastrin I, but had no effect on amylase release stimulated by other secretagogues or by agents bypassing receptors. Similarly, binding of N-methylscopolamine to pancreatic acini was not inhibited by L-364,718. In the isolated perfused pancreata, L-364,718 inhibited CCK-8-stimulated pancreatic exocrine secretion and insulin release. The inhibitory effects of L-364,718 were more potent for insulin release than for exocrine secretion and persisted even after the removal of L-364,718 infusion. These results clearly demonstrate that L-364,718 is a specific, potent, and prolonged antagonist of CCK's stimulatory actions on pancreatic acinar and B cells.

New model of acute necrotizing pancreatitis induced by excessive doses of arginine in rats

We examined the biological and histologic characteristics of a new experimental model of acute necrotizing pancreatitis induced by excessive doses of arginine in rats. Rats were given a single intraperitoneal injection of 500 mg/100 g body weight of L-arginine. At 12-24 hr after the arginine injection, serum levels of amylase, lipase, and anionic trypsin(ogen) reached respective peak values 2, 5, and 20 times those of control rats without arginine and returned to control levels after 24-48 hr. The contents of pancreatic protein, DNA, and digestive enzymes were markedly reduced after the arginine injection and reached their nadirs at 72 hr. After 14 days these levels were almost normal. Histologic examination revealed a number of small vesicles within acinar cells at 6 hr, which were identified as markedly swollen mitochondria by the electron microscope. Other intracellular organelles and nuclei also showed degenerative changes. At 12 hr interstitial edema appeared, and acinar cell necrosis was seen after 24 hr. The extent and severity of necrotic changes of pancreatic exocrine tissue with inflammatory cell infiltration were maximal at 72 hr. At seven days, pancreatic acinar cells began to regenerate, and pancreatic architecture appeared almost normal after 14 days. The present study has demonstrated that the administration of excessive doses of arginine induces a new, noninvasive experimental model of acute necrotizing pancreatitis.

Overproduction and crystallization of tryptophanase from recombinant cells of Escherichia coli

We have cloned the tryptophanase structural gene from Escherichia coli B/1t7-A into E. coli K-12 MD55 with a vector plasmid, pBR322. The cloned cells produced a large amount of the enzyme corresponding to more than 30% of the total soluble protein. With the enzyme obtained by this overproduction system, we have prepared three different crystals of tryptophanase, apo-enzyme, holo-enzyme, and a complex of holo-enzyme and L-alanine, by using polyethylene glycol 4000 or potassium phosphate as a precipitant and the hanging drop method. These single crystals appeared to be suitable for X-ray diffraction analysis.

Beneficial effects of the synthetic trypsin inhibitor camostate in cerulein-induced acute pancreatitis in rats

The therapeutic effect and the mechanism of action of the synthetic trypsin inhibitor camostate were studied in a rat model of acute interstitial pancreatitis induced by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals. Rats with acute pancreatitis were given either 100 mg/kg body weight camostate or volume- and pH-adjusted water via an orogastric tube 30 min after the last cerulein injection. The elevation of serum amylase activity was significantly reduced by camostate treatment and the peak value was seen 1 hr earlier than that observed in the rats that did not receive camostate. Camostate also inhibited the reduction in pancreatic content of lipase and amylase seen during experimental pancreatitis. These effects were accompanied by alleviation of the histologic signs of acute pancreatitis such as cellular infiltration and acinar cell vacuolization. After oral administration, camostate and its metabolite were absorbed from the intestine and were detectable in plasma for more than 6 hr in concentrations high enough to have antiprotease activity. In addition, camostate in the duodenum was able to increase pancreatic juice flow and protein output and to stimulate endogenous secretin release. These results suggest that oral administration of camostate reduces the severity of cerulein-induced acute pancreatitis by releasing endogenous secretin and by its antiprotease activity.

Kinetic approach with ab initio MO method on ionic selectivity and size in sodium channel

Three kinds of models for ionic selectivity and size of the filter in sodium channel have been treated by using ab initio molecular orbital (MO) calculations with MINI-3 and MIDI-3* basis sets. A three-components system, HCO2M-H2O (M = Li+, Na+ or K+), is acceptable for describing experimental facts well. Thermochemical parameters obtained from harmonic vibrational analysis with MINI-3 basis sets, for the translocation of the permeant metal cations in the HCO2M-H2O system, are that the activation enthalpies for Li+, Na+ and K+ are 7.0, 6.4 and 23.4 kJ/mol, and also the free energies of activation are 10.6, 1.5 and 19.0 kJ/mol, respectively. These results are qualitatively in good correspondence with experimental facts of the ion selectivity of the channel. One of water molecule was found to have a key role in the translocation of the permeant cations.

[Plasma cholecystokinin concentration in patients with chronic pancreatitis measured by bioassay]

We developed a specific and sensitive bioassay for measuring plasma cholecystokinin (CCK) in human and investigated CCK response after a test meal in patients with chronic pancreatitis. Treatment with cycloheximide increased the sensitivity and responsiveness of isolated rat pancreatic acini to CCK-octapeptide (CCK-8) and thus plasma levels of CCK-8 as low was 0.17 pM were detectable. Fasting plasma CCK levels in normal subjects as CCK-8 equivalents were 0.75 +/- 0.25 pM and rose to a peak of 6.2 +/- 0.68 pM at 45 min after a test meal consisting of 400 ml milk and 2 boiled eggs. Basal and stimulated plasma levels of CCK-8 in patients with non-calcified chronic pancreatitis were significantly higher than those in normal subjects. In contrast, postprandial responses of plasma CCK-8 in patients with calcified chronic pancreatitis was significantly low compared to those in control subjects, although basal plasma levels were not significantly different from those in controls.

Hydrocortisone treatment increases the sensitivity and responsiveness to cholecystokinin in rat pancreas

The effects of hydrocortisone treatment on the secretory abilities of pancreatic acini to various secretagogues were studied. Rats were given subcutaneous injections of hydrocortisone at doses of 1.25, 2.5, or 5.0 mg/kg body wt once daily for 7 days. Hydrocortisone led to a small dose-dependent increase in pancreatic wet weight per 100 g body wt, which was associated with an increase in both total protein and DNA contents. In acini prepared from hydrocortisone-treated rats, both the responsiveness and the sensitivity to cholecystokinin octapeptide (CCK-8) was increased. The concentration dependence of cellular Ca2+ mobilization in response to CCK-8 was also shifted to lower concentrations in acini from hydrocortisone-treated rats compared with control rat acini. In vivo administration of hydrocortisone caused a significant increase in the affinity of 125I-CCK-8 binding to high-affinity receptors. The secretory responsiveness to carbamylcholine and bombesin, but not to secretin, was also increased but without any change in the sensitivity. Moreover, the hydrocortisone treatment increased the secretory responsiveness of acini to the Ca2+ ionophore A23187 and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate but did not to an adenosine 3',5'-cyclic monophosphate analogue, 8-bromoadenosine 3',5'-cyclic monophosphate. The present observations suggest that in vivo glucocorticoid administration affects both the CCK receptors and a postreceptor loci.

Pepsinogen secretion from cultured rat gastric mucosal cells

Rat gastric mucosal cells were isolated with the aid of 0.1% collagenase and Dispase. Pepsinogen secretion from these cells was stimulated by carbachol, cholecystokinin octapeptide (CCK(S)-8) and pentagastrin, but not by histamine. Attempts to obtain a sufficient number of cells using a higher concentration of Dispase resulted in disappearance of the responses to secretagogues. However, when gastric mucosal cells thus prepared were cultured for 24 h in a CO2 incubator, they were found to respond not only to carbachol, CCK(S)-8 and pentagastrin, but also to histamine, resulting in an increase in pepsinogen secretion. The secretagogue-induced pepsinogen secretion was inhibited by its antagonist in a dose-dependent manner. These results suggest that the receptor present in chief cells for pepsinogen secretion was destroyed during the isolation procedure and regenerated during culture.