Stress in middle-aged women: influence of Type A behavior and narcissism

The authors examined (1) strength of stress, (2) awareness of stress, and (3) influence of type A behavior and narcissistic personality on stress and its related factors in a sample of 500 middle-aged women. Compared to 400 middle-aged working men, the women scored lower on the type A and coping scales, suggesting the possibility that women with high scores on type A behavior cope better with stress. Moreover, type A behavior in women was related to narcissistic personality. The strength of stressors and stress coping in type A women are affected by the severity of narcissism.

Enterogenous cyst in the fourth ventricle--case report

A 53-year-old male presented with a rare enterogenous cyst in the fourth ventricle associated with repeated ventriculoperitoneal shunt malfunction. Surgical excision of the cyst resolved the shunt problems. Electron microscopy findings of the surgical sample were microvilli covered with electron-dense coating materials, basement membrane, and several intercellular junctional devices, suggesting the cyst was derived from the endodermal structure. The viscous and gelatinous contents of the cyst might be responsible for the shunt malfunction.

Role of hypoxia on increased blood pressure in patients with obstructive sleep apnoea

BACKGROUND

Cyclical changes in systemic blood pressure occur during apnoeic episodes in patients with obstructive sleep apnoea (OSA). Although several factors including arterial hypoxaemia, intrathoracic pressure changes, and disruption of sleep architecture have been reported to be responsible for these changes in blood pressure, the relative importance of each factor remains unclear. This study assessed the role of hypoxaemia on the increase in blood pressure during apnoeic episodes.

METHODS

The blood pressure in apnoeic episodes during sleep and the blood pressure response to isocapnic intermittent hypoxia whilst awake were measured in 10 men with OSA. While asleep the blood pressure was measured non-invasively using a Finapres blood pressure monitor with polysomnography. The response of the blood pressure to hypoxia whilst awake was also measured while the subjects intermittently breathed a hypoxic (5% or 7% oxygen) gas mixture. Each hypoxic gas exposure was continued until a nadir arterial oxygen saturation (nSaO2) of less than 75% was reached, or for a period of 100 seconds. The exposure was repeated five times in succession with five interposed breaths of room air in each run.

RESULTS

The mean (SD) increase in blood pressure (delta MBP) during apnoeic episodes was 42.1 (17.3) mm Hg during rapid eye movement (REM) sleep and 31.9 (12.5) mm Hg during non-REM sleep. The delta MBP during apnoeic episodes showed a correlation with the decrease of nSaO2 (delta SaO2) (r2 = 0.30). The change in blood pressure in response to intermittent hypoxia whilst awake was cyclical and qualitatively similar to that during apnoeic episodes. Averaged delta MBP at an SaO2 of 7% and 5% oxygen was 12.6 (5.7) and 13.4 (3.6) mm Hg, respectively, whereas the averaged delta MBP at the same delta SaO2 during apnoeic episodes was 38.4 (15.5) and 45.2 (20.5) mm Hg, respectively.

CONCLUSIONS

The blood pressure response to desaturation whilst awake was about one third of that during apnoeic episodes. These results suggest that factors other than hypoxia may play an important part in raising the blood pressure during obstructive sleep apnoea.

Role of GABAB receptors in the control of hypoglossal motoneurons in vivo

There is little information on GABAB receptor-mediated effects on orofacial motoneurons. We recorded the inspiratory activity from both hypoglossal (XII) nerves in urethane-anesthetized, paralyzed, vagotomized and artificially ventilated rats. A GABAB receptor agonist, baclofen, or antagonist, CGP-35348, was microinjected into one XII nucleus. Baclofen rapidly reduced the XII nerve activity in a dose-dependent manner by over 50%. The antagonist caused a delayed suppression of activity by 40%. We conclude that: (1) GABAB receptors within the XII nucleus may suppress the activity of inspiratory XII motoneurons, but they are not tonically active under the conditions of our experiment; (2) there is a net endogenous excitatory effect in XII motoneurons that is mediated by GABAB receptors located in the reticular formation surrounding the XII nucleus.

Influences of urethane anesthesia on indomethacin-induced gastric mucosal lesions in rats. Relation to blood glucose levels

Effects of urethane on gastric motility and mucosal ulcerogenic responses induced by indomethacin were investigated in the rat in relation to blood glucose levels (BGL) and compared with those of pentobarbital Na. Urethane (1.25 g/kg) given intraperitoneally, caused a progressive and significant rise in BGL, while pentobarbital (30 mg/kg) given intraperitoneally did not affect BGL. Subcutaneous administration of indomethacin (25 mg/kg) caused high-amplitude gastric contractions and induced hemorrhagic lesions in the stomachs of conscious rats. These lesions were significantly inhibited by urethane but not pentobarbital. Administration of urethane abolished basal gastric motility and almost completely suppressed the motility responses induced by indomethacin, while pentobarbital did not have much effect on gastric motility under basal and indomethacin-stimulated conditions. Acid secretion was significantly decreased by urethane and increased by pentobarbital. Pretreatment of the animals with yohimbine (5 mg/kg, subcutaneously) but not prazosin (0.5 mg/kg) inhibited the elevation in BGL seen after administration of urethane and allowed resumption both gastric motility and ulcerogenic responses induced by indomethacin, with less change in acid secretion. These results suggest that intraperitoneal administration of urethane prevented indomethacin-induced gastric lesions, probably by inhibiting the enhanced gastric motility response, and this effect may relate to its hyperglycemic action mediated by alpha 2-adrenoceptors. These findings also provide further evidence to support the importance of gastric motility in the pathogenesis of these lesions.

Capsaicin-sensitive sensory neurons in healing gastric lesions induced by HCl in rats

The role of capsaicin-sensitive sensory neurons in the healing of HCl-induced gastric lesions was investigated in rats. Rats fasted for 18 hr were given 0.6 N HCl orally for induction of gastric lesions, and they were fed normally from 1 hr later. On various days after HCl treatment, area of lesions, acid secretion, mucosal H+ permeability, and blood flow responses were measured. Functional ablation of capsaicin-sensitive sensory neurons was performed two weeks before the experiment by subcutaneous injections of high-dose capsaicin. Sensory deafferentation did not affect the development of gastric damage in response to HCl but significantly delayed the healing of these lesions. The mucosa damaged by HCl secreted less acid but showed significant rise in H+ permeability, resulting in acid back-diffusion accompanied by an increase of mucosal blood flow. Sensory deafferentation had no effect on acid secretion and mucosal permeability changes in the damaged stomach but completely blocked the hyperemic response caused by acid back-diffusion. Capsaicin-sensitive sensory neurons may contribute to healing of gastric lesions, probably by mediating the mucosal hyperemic responses associated with acid back-diffusion and by facilitating acid disposal in the mucosa.

Acceleration of healing of gastric ulcers induced in rats by liquid diet: importance of tissue contraction

We examined the effect of a liquid diet or a combined diet of liquid plus cellulose on the healing of gastric ulcers induced in rats in comparison with that of solid chow. Ulcers were induced in the fundus of the stomach by luminal application of an acetic acid solution. The healing of ulcers could be divided into two phases based on the healing rate: early phase (days 1 to 10) and late phase (days 10 to 20). The liquid diet, but not the combined one, administered for 10 days significantly accelerated ulcer healing in both the early and late phases. The length of the ruptured muscularis mucosa decreased only in the liquid diet group in both phases. Regeneration of the ulcerated mucosa in the chow diet group was observed only in the late phase, it being markedly inhibited in the liquid diet group. The serum gastrin level significantly decreased in the liquid and combined diet groups in contrast to that in the chow group. The liquid and combined diets significantly reduced gastric mucosal DNA synthesis. We conclude that 1) the healing in this gastric ulcer model comprises two phases, and 2) tissue contraction is a major factor for the healing of gastric ulcers in the early phase, while both tissue contraction and regeneration of the ulcerated mucosa are involved in the healing in the late phase.

Effects of prostaglandin E2 inhalation on hypercapnic response in normal subjects

It is known that the ventilatory response to carbon dioxide (CO2) is increased in asthmatics with airway obstruction. Increased vagal afferent activity as well as increased airway resistance have been postulated as the causative mechanisms. However, whether increased vagal afferent activity without bronchoconstriction increases the ventilatory response to CO2 has not been investigated in humans. We examined the effects of prostaglandin E2 (PGE2) inhalation, which is known to stimulate vagal afferent receptors in the lung without an increase in airway resistance, on the respiratory response to CO2 in seven healthy male subjects. Either physiologic saline or PGE2 (100 micrograms/ml) was inhaled through a Bird nebulizer for 3 min. Twenty minutes after each inhalation, the responses of minute ventilation (VE) and occlusion pressure (P0.1) to hyperoxic hypercapnia were measured. Both the relationships between VE and P0.1 to an increase in tension of end-tidal CO2 (PETCO2) were analyzed by linear regression. Although the mean value of respiratory resistance after PGE2 (3.0 cm H2O/L/s +/- 0.4) did not differ significantly from that after saline (3.1 cm H2O/L/s +/- 0.4), inhaled PGE2 significantly increased the hypercapnic response. This result suggests that the increased vagal afferent activity per se plays an important role in increasing the hypercapnic ventilatory response in humans.

Mechanisms underlying stimulation of gastroduodenal HCO3- secretion by NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase, in rats

We investigated the mechanism underlying stimulation of HCO3- secretion by the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in the gastroduodenal mucosa of anesthetized rats. A chambered stomach (in the presence of omeprazole) or a duodenal loop was perfused with saline, and HCO3- secretion was measured at pH 7.0 by a pH-stat method. Intravenous administration of L-NAME increased gastroduodenal HCO3- secretion with a concomitant rise in arterial blood pressure and a decrease in heart rate, and the changes were all antagonized by simultaneous administration of L-arginine. Vagotomy had no effect on the increased blood pressure response, but significantly inhibited the decrease of heart rate and increase of HCO3- secretion caused by L-NAME. The HCO3- stimulatory action of L-NAME was also inhibited by prior administration of yohimbine or prazosin. These agents alone lowered blood pressure and reduced the magnitude of the blood pressure response caused by L-NAME, leading to inhibition of heart rate changes. When delta HCO3- output induced by L-NAME was plotted against delta blood pressure change (from basal values) under various conditions, a significant relationship was found between these two factors. These results suggest that L-NAME stimulates gastroduodenal HCO3- secretion in association with the inhibition of endogenous NO production, and this mechanism may be in part mediated by a neural reflex through the vagal efferent nerve, resulting from the pressor response to L-NAME.

Differential dynamics of neurofilament-H protein and neurofilament-L protein in neurons

Neurofilaments (NFs) are composed of triplet proteins, NF-H, NF-M, and NF-L. To understand the dynamics of NFs in vivo, we studied the dynamics of NF-H and compared them to those of NF-L, using the combination of microinjection technique and fluorescence recovery after photobleaching. In the case of NF-L protein, the bleached zone gradually restored its fluorescence intensity with a recovery half time of approximately 35 min. On the other hand, recovery of the bleached zone of NF-H was considerably faster, taking place in approximately 19 min. However, in both cases the bleached zone was stationary. Thus, it was suggested that NF-H is the dynamic component of the NF array and is interchangeable, but that it assembles with the other neurofilament triplet proteins in a more exchangeable way, implying that the location of NF-H is in the periphery of the core NF array mainly composed of NF-L subunits. Immunoelectron microscopy investigations of the incorporation sites of NF-H labeled with biotin compounds also revealed the lateral insertion of NF-H subunits into the preexisting NF array, taking after the pattern seen in the case of NF-L. In summary, our results demonstrate that the dynamics of the L and H subunit proteins in situ are quite different from each other, suggesting different and separated mechanisms or structural specialization underlying the behavior of the two proteins.

Upper airway muscle activity during REM and non-REM sleep of patients with obstructive apnea

We measured electromyograms (EMGs) of genioglossus muscle (GG) and inspiratory intercostal muscle (IIM) in both rapid eye movement (REM) sleep and non-REM sleep of 12 patients with obstructive sleep apnea (OSA) to examine the influence of different sleep stages on upper airway muscle activity during sleep apnea. Quantifications of both muscle activities were assessed by their individual peak amplitude of integrated inspiratory EMG. Genioglossus and IIM activities showed a qualitatively similar cyclic change with an alteration of apneic and ventilatory phases during both non-REM and REM sleep. Both muscle activities increased gradually in the late apneic phase and reached each peak at the opening of the upper airway and, subsequently, decreased gradually. There were no significant differences in both muscles activities in either the ventilatory or early apneic phase between non-REM sleep and REM sleep. On the other hand, GG and IIM activities in the late apneic phase during REM sleep were significantly lower than those during non-REM sleep. The relative activity of GG to IIM in the late apneic phase was significantly lower during REM sleep than that during non-REM sleep. These results indicate that upper airway and intercostal muscle activation in the later apneic phase during REM sleep were inhibited compared with those during non-REM sleep and that this inhibition was observed predominantly in upper airway muscles.

Effect of anterior unilateral vagotomy on healing of kissing gastric ulcers induced in rats

Unilateral vagotomy causes atrophy of the denervated fundic mucosa in rat stomachs. We examined whether or not unilateral vagotomy delays healing of gastric ulcers induced on the denervated mucosa. Kissing ulcers were induced in the fundus of rat stomachs by intraluminal application of an acetic acid solution. Anterior unilateral vagotomy was performed subdiaphragmatically at the time of ulceration. The healing of gastric ulcers induced on the denervated side was significantly enhanced, whereas that on the vagally intact side was not affected. In unilaterally denervated animals, the total gastric acid secretion (both basal and 2-deoxy-D-glucose stimulated) was inhibited, and the pH around the ulcers was increased only in the anterior side. Repeatedly administered histamine failed to affect the enhanced ulcer healing in unilaterally denervated animals. Gastric emptying and mucosal cell proliferation stimulated by food or pentagastrin were unaffected. Serum gastrin significantly increased 19 days after vagotomy. Gastric relaxation on refeeding was inhibited on the denervated side, but this inhibition of relaxation was reversed by hexamethonium treatment. A liquid diet significantly enhanced the healing of ulcers on both the denervated and vagally intact sides. The mechanism by which unilateral vagotomy accelerates the healing of ulcers on the denervated side appears to relate to the inhibition of both gastric acid secretion and gastric relaxation.

Acid secretory and duodenal ulcerogenic responses induced by mepirizole in anesthetized rats. Relation to body temperature

The role of body temperature in the acid stimulatory mechanism by mepirizole, a duodenal ulcerogen, was investigated in urethane-anesthetized rats. Subcutaneous administration of mepirizole (60 and 200 mg/kg) increased acid secretion in a dose-dependent manner and resulted in duodenal lesions within 8 hr. The acid secretory and ulcerogenic responses induced by mepirizole were inhibited completely by vagotomy and significantly reduced by subcutaneous pretreatment with atropine (1 mg/kg), hexamethonium (10 mg/kg), or clonidine (1 mg/kg). During anesthesia, body temperature was decreased to 34 degrees C in control rats but further reduced to 31 degrees C after administration of mepirizole. When body temperature was maintained at 36 degrees C during a test period, mepirizole caused significantly less effect on acid secretion and produced less damage in the duodenum. In addition, intracisternal administration of antiserum of thyrotropin-releasing hormone (TRH: 5 mu1/rat) also significantly inhibited acid hypersecretion and development of duodenal lesions in response to mepirizole. When acid output induced by mepirizole was plotted against duodenal lesion score from one group to another, a significant linear relationship was found between these two values (r = 0.814, P < 0.05). We conclude that mepirizole induced vagally mediated acid secretion and duodenal lesions in anesthetized rats. These responses may occur centrally in association with lowering of body temperature, which potentiates the acid stimulatory effect of mepirizole, probably through a TRH-dependent mechanism.

In vivo release of glutamate in nucleus tractus solitarii of the rat during hypoxia

1. An attempt has been made to test the hypothesis that, in the caudal part of nucleus tractus solitarii (NTS) where carotid sinus nerve (CSN) afferents project, L-glutamate (Glut) modulates the hypoxic ventilatory response. 2. Unanaesthetized, peripherally chemodenervated (carotid body denervated; CBD) and sham-operated, freely moving rats were used. During peripheral chemoreceptor stimulation by hypoxia (10% O2 for 30 min) or doxapram (Dox) infusion (2 mg kg-1 (30 min)-1), ventilation was recorded and successively, under the same conditions, the extracellular Glut concentration ([Glut]o) in the caudal NTS was measured by in vivo microdialysis. [Glut]o was also measured during hyperoxic hypercapnia (10% CO2-30% O2 for 30 min). 3. Furthermore, the effects on ventilation of exogenous Glut, the NMDA (N-methyl-D-aspartate) receptor antagonist MK-801 or the ionotropic receptor antagonist kynurenate microinjected into the caudal NTS were investigated in sham-operated rats. 4. In sham-operated rats, both ventilation and [Glut]o in NTS were increased during peripheral chemoreceptor stimulation. On the other hand, no increases in either ventilation or Glut release were observed in CBD rats. In spite of ventilatory augmentation during hypercapnia, no response of [Glut]o to hypercapnia was observed in either group. 5. Local Glut application into NTS increased ventilation. Pretreatment with MK-801 or kynurenate reduced the hypoxic ventilatory response. This reduction in ventilation was mainly due to the decrease in tidal volume. 6. These results suggest that hypoxia induced the release of Glut in NTS and that this effect was mediated by arterial chemosensory input.

Altered microtubule organization in small-calibre axons of mice lacking tau protein

The tau gene encodes a protein (Tau) that is a major neuronal microtubule-associated protein localized mostly in axons. It has microtubule-binding and tubulin-polymerizing activity in vitro and is thought to make short crossbridges between axonal microtubules. Further, tau-transfected non-neuronal cells extend long axon-like processes in which microtubule bundles resembling those in axons are formed. In contrast, tau antisense oligonucleotides selectively suppress axonal elongation in cultured neurons. Thus tau is thought to be essential for neuronal cell morphogenesis, especially axonal elongation and maintenance. To test this hypothesis, we used gene targeting to produce mice lacking the tau gene. We show that the nervous system of tau-deficient mice appears to be normal immunohistologically. Furthermore, axonal elongation is not affected in cultured neurons. But in some small-calibre axons, microtubule stability is decreased and microtubule organization is significantly changed. We observed an increase in microtubule-associated protein 1A which may compensate for the functions of tau in large-calibre axons. Our results argue against the suggested role of tau in axonal elongation but confirm that it is crucial in the stabilization and organization of axonal microtubules in a certain type of axon.

The role of capsaicin-sensitive sensory neurons in healing of HCl-induced gastric mucosal lesions in rats

BACKGROUND/AIMS

Capsaicin-sensitive sensory neurons are important in protecting the stomach against damage. This study investigated the role of these sensory neurons in the healing of gastric lesions.

METHODS

Rats fasted for 18 hours were given 1 mL of 0.6N HCl orally for induction of gastric lesions; they were then fed normally from 1 hour later. On various days after HCl treatment, the area of lesion, acid secretion, mucosal DNA synthesis, mucosal H+ permeability, and blood flow responses were measured.

RESULTS

Ablation of sensory neurons by capsaicin pretreatment did not affect the development of gastric lesions in response to HCl but significantly delayed the healing of these lesions. The damaged mucosa secreted less acid and had minimal changes in DNA synthesis but showed a marked increase in H+ permeability, resulting in luminal acid loss accompanied by an increase of mucosal blood flow. Sensory deafferentation did not have any influence on such changes in the damaged stomach, except the mucosal hyperemic response to acid.

CONCLUSIONS

Capsaicin-sensitive sensory neurons may contribute to the healing of gastric lesions by mediating the mucosal hyperemic responses associated with acid back-diffusion and by facilitating acid disposal in the mucosa.

Chemosensitivity and perception of dyspnea in patients with a history of near-fatal asthma

BACKGROUND

Many deaths from attacks of asthma may be preventable. However, the difficulty in preventing fatal attacks is that not all the pathophysiologic risk factors have been identified.

METHODS

To examine whether dyspnea and chemosensitivity to hypoxia and hypercapnia are factors in fatal asthma attacks, we studied 11 patients with asthma who had had near-fatal attacks, 11 patients with asthma who had not had near-fatal attacks, and 16 normal subjects. Their respiratory responses to hypoxia and hypercapnia, determined by the standard rebreathing technique while the patients were in remission, were assessed in terms of the slopes of ventilation and airway occlusion pressure as a function of the percentage of arterial oxygen saturation and end-tidal carbon dioxide tension, respectively. The perception of dyspnea was scored on the Borg scale during breathing through inspiratory resistances ranging from 0 to 30.9 cm of water per liter per second.

RESULTS

The mean (+/- SD) hypoxic ventilatory response (0.14 +/- 0.12 liter per minute per percent of arterial oxygen saturation) and airway occlusion pressure (0.05 +/- 0.05 cm of water per percent of arterial oxygen saturation) were significantly lower in the patients with near-fatal asthma than in the normal subjects (0.60 +/- 0.35, P < 0.001, and 0.16 +/- 0.08, P < 0.001, respectively) and the patients with asthma who had not had near-fatal attacks (0.46 +/- 0.29, P = 0.003, and 0.15 +/- 0.09, P = 0.004). The Borg score was also significantly lower in the patients with near-fatal asthma than in the normal subjects, and their lower hypoxic response was coupled with a blunted perception of dyspnea.

CONCLUSIONS

Reduced chemosensitivity to hypoxia and blunted perception of dyspnea may predispose patients to fatal asthma attacks.

Effects of submental stimulation for several consecutive nights in patients with obstructive sleep apnoea

BACKGROUND

It has previously been reported that short term submental stimulation can reduce the frequency of apnoea and improve sleep architecture in patients with obstructive sleep apnoea. The effects of submental stimulation during consecutive nights on apnoea or on daytime sleepiness have not, however, been studied.

METHODS

Patients with obstructive sleep apnoea were studied by polysomnography on a control night, for five consecutive nights of submental stimulation, and on three following nights (n = 8). A multiple sleep latency test (MSLT) (n = 8) and measurement of the upper airway resistance (n = 5) were performed during the day after the polysomnographic study, on the control night, and on the fifth stimulation night. In an additional five patients with obstructive sleep apnoea, matched for age, sex, and weight, the effects of two nights of stimulation were examined for comparison. Submental stimulation began when an apnoea lasted for five seconds and stopped with the resumption of breathing as detected by oronasal flow.

RESULTS

The apnoea index, the number of times per hour that SaO2 dropped below 85% (SaO2 < 85%/hour), and the total apnoea duration expressed as a percentage of total sleep time during stimulation nights decreased to approximately 50% of the corresponding values on the control night. This improvement persisted for at least two nights after the five consecutive stimulation nights, but not after the two consecutive stimulation nights. Sleep architecture and MSLT following the stimulation nights improved but upper airway resistance did not change.

CONCLUSIONS

Submental stimulation for five consecutive nights in patients with obstructive sleep apnoea improved the breathing disturbance, sleep quality, and daytime sleepiness. The effect lasted for the following two nights, but did not completely abolish the sleep disordered breathing.

[Mass screening for prostate cancer at a local town--five-year results and screening system]

The results of a mass screening examination for prostate cancer conducted from 1989 to 1993 at a local town, Kawagoe-cho, in Mie Prefecture were evaluated. Among the 216 examinees, 4 were found to have prostate cancer. The most accurate examination was the prostate specific antigen (PSA), which was followed by digital examination and transrectal ultrasound. The applicants for the prostate cancer screening accounted for only 8% of the Kawagoe-cho male residents over 40 years old. An educational campaign of prostate disease in the area must be started to increase the number of applicants. We concluded that the most effective modality for the screening program was a combination of PSA and digital examination in the field study, and transrectal ultrasound accompanied by systemic biopsy results in the second tool for screening.

Effect of intraduodenally administered histamine on gastric acid secretion in rats and guinea pigs

We examined the effect of histamine administered intraduodenally as well as subcutaneously or intravenously on the gastric acid secretion in rats and guinea pigs, using a newly devised cannula. Intraduodenally administered histamine dihydrochloride caused a significant dose-dependent increase in the gastric acid secretion in rats. The maximal acid secretion, which corresponded to that after subcutaneous (20 mg/kg) or intravenous (10 mg/kg/hr) administration of histamine, was observed within 30 min after intraduodenal administration (40 mg/kg). The plasma concentrations of histamine determined 30 min after intraduodenal, subcutaneous, and intravenous administration of histamine were nearly the same. Pretreatment with aminoguanidine sulfate (diamine oxidase inhibitor) at 30 mg/kg significantly increased the gastric acid secretion caused by intraduodenal histamine. The gastric acid secretion stimulated by intraduodenal histamine was significantly inhibited by cimetidine, pirenzepine, and omeprazole, but remained unchanged with tripelennamine. Intraduodenal histamine (20 mg/kg) also maximally stimulated the gastric acid secretion in guinea pigs. The response was comparable to that with subcutaneous histamine (1 mg/kg). We conclude that intraduodenal histamine has the ability to stimulate gastric acid secretion in both rats and guinea pigs.

Induction of gastric lesions and hypoglycemic response by food deprivation in streptozotocin-diabetic rats

Overnight fasting causes hemorrhagic lesions in the stomach of streptozotocin (STZ)-induced diabetic rats, but the pathogenetic mechanism remains unknown. The present study was performed to investigate the pathogenesis of such lesions developed in STZ-diabetic rats after starvation, mainly in relation to blood glucose changes. A single injection of STZ (70 mg/kg, intraperitoneally) induced hyperglycemic conditions one week after the administration, and high blood glucose levels (BGL: > 350 mg%) remained up to three weeks later. The STZ-diabetic rats developed gastric lesions with the marked reduction of BGL after 18 hr of fasting, depending upon the duration of diabetes; the lesion score and delta BGL reduction in the 3-week-old STZ rats were 32.0 +/- 7.8 mm and > 250 mg/100 ml, respectively. Acid secretion in the pylorus-ligated rats was not significantly changed in the STZ-induced diabetic conditions for the initial two weeks but slightly decreased at three weeks when compared with normal rats. Fasting of normal rats for 18 hr did not cause either BGL reduction or any lesion in the stomach. In the 3-week-old STZ animals, the severity of gastric lesions increased with the duration of fasting (4-18 hr) and was again closely associated with the degree of delta BGL reduction. These lesions induced by 18 hr of starvation in 3-week-old STZ rats were significantly inhibited by pretreatment with insulin (4 units/rat/day) for the last one week to maintain BGL within normal ranges or by intravenous infusion of 25% glucose during fasting period. Both of these treatments significantly prevented BGL reduction in response to fasting.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA alterations in cells from hereditary non-polyposis colorectal cancer patients

To determine if the MCC, DCC or p53 gene is associated with susceptibility to hereditary non-polyposis colorectal cancer (HNPCC), these genes in normal cells from 12 HNPCC patients were analysed by polymerase chain reaction-single strand conformation polymorphism analysis. No changes which may alter the amino acid sequences of these genes were detected, suggesting that these genes are not associated with the susceptibility to HNPCC. Only one of nine HNPCC cancers showed mutations in the MCC and p53 genes on the same analysis. Loss of heterozygosity in chromosomes 5q, 17p, 18q and 22 was detected in four of the nine cancers, all of them being positive as to metastasis to lymph nodes. Abnormalities of the (CA)n repeat were found in six cancers, including all four without metastasis. These data indicate that tumor suppressor genes in chromosomes 5q, 17p, 18q and 22 are associated with the late stage of colorectal tumorigenesis in HNPCC, whereas the (CA)n repeat abnormalities are an early event of tumorigenesis and more essential to HNPCC.

Endogenous nitric oxide in gastric alkaline response in the rat stomach after damage

BACKGROUND/AIMS

The gastric mucosa responds to hypertonic NaCl by significantly decreasing acid secretion. This study examined the role of nitric oxide in this phenomenon.

METHODS

A rat stomach was mounted in an ex vivo chamber and perfused with saline; then the potential difference (PD), pH, and acid and/or alkaline responses were measured before and after the application of 1 mol/L NaCl with or without pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO biosynthesis.

RESULTS

A dose of 1 mol/L NaCl caused a reduction in PD, a decrease in basal and histamine-stimulated acid secretion, and an increase in luminal HCO3-. Prior administration of L-NAME did not affect either the PD or the HCO3- response but significantly attenuated the inhibitory effect of 1 mol/L NaCl on acid secretion. This effect of L-NAME was antagonized by the simultaneous administration with L-arginine but not D-arginine. Histamine-stimulated acid secretion in the normal stomach was significantly reduced by the exogenous NO donor nitroprusside but not by L-NAME.

CONCLUSIONS

NO is involved in the mechanism of the gastric alkaline response after damage with 1 mol/L NaCl. Irritation of the gastric mucosa by hypertonic NaCl may release endogenous NO, which in turn inhibits acid secretion and unmasks luminal alkalinization caused by HCO3- flux in the damaged portion.

Risk factors for the postoperative local recurrence of tongue carcinoma

Clinical and histologic studies on the risk factors for the postoperative local recurrence of tongue carcinoma were analyzed in 51 patients. Postoperative local recurrence occurred in 12 (23.5%), with almost all developing within the first 12 months after surgery. A comparison of patients with and without recurrence indicated that the risk factors for recurrence were 1) endophytic tumor growth, 2) grade 4 pattern of histologic invasion, and 3) tumor within 5 mm of the surgical margin (especially the deep margin). All T1 tumors were less than 5 mm deep, indicating that it is reasonable for partial glossectomy to be performed in patients with T1 carcinoma. However, for T2 through T4 carcinoma it seems that more extensive surgery should be performed because of the variability in depth of tumor invasion. The 5-year survival rate of the patients with recurrence was 45% and that of patients without recurrence was 73.7% (P < .01). The overall prognosis of tongue carcinoma should improve when surgeons take a more prudent attitude to the treatment of patients with these risk factors.