Enhanced secretion and activation of matrilysin during malignant conversion of human colorectal epithelium and its relationship with invasive potential of colon cancer cells

BACKGROUND

Matrilysin is a member of the matrix metalloproteinase gene family which is believed to play an important role in tumor progression. Matrilysin mRNA has been reported to be overexpressed in colorectal cancer. The aim of this study was to evaluate the enzyme activity of this protein during colorectal cancer. The aim of this study was to evaluate the enzyme activity of this protein during colorectal carcinogenesis and its relationship with the invasiveness of colorectal cancer cells.

METHODS

We have examined the levels of secreted matrilysin in various epithelial disorders of the colon using casein zymography. We have also examined the effect of matrilysin on the in vitro invasiveness of colorectal cancer cells using a modified Boyden Chamber method.

RESULTS

The enzyme activities of matrilysin were detected in cancer tissue and adenoma tissue, whereas they were hardly detectable in hyperplastic polyps, mildly inflamed regions of ulcerative colitis, and normal colon tissue. Enhanced secretion and enhanced activation of matrilysin were observed in cancer. An in vitro invasion assay revealed that the levels of secreted matrilysin-transfectants correlated positively with invasiveness.

CONCLUSIONS

Our data suggest that the secretion and activation of matrilysin may be up-regulated during malignant conversion of colorectal epithelium. Matrilysin appears to contribute to in vitro invasiveness of colon cancer cells. Inhibitors of the enzyme may be of value in preventing colorectal cancer progression.

Gas chromatography/combustion/isotope ratio mass spectrometric comparison of N-acetyl- and N-pivaloyl amino acid esters to measure 15N isotopic abundances in physiological samples: a pilot study on amino acid synthesis in the upper gastro-intestinal tract of minipigs

There is evidence that in animals and also in humans, non-specific nitrogen is used for de novo synthesis of indispensable amino acids by the microflora of the gastro-intestinal tract. Gas chromatography/combustion/isotope ratio mass spectrometry was applied to investigate whether lysine of intestinal origin is available for body protein synthesis. Two minipigs with an end-to-end ileorectal anastomosis received orally equimolar amounts of 15N as ammonium chloride or urea twice a day for 10 days. Samples of blood and ileal digesta were collected before and throughout the 10 days; tissue samples were taken at termination of the experiment. The N-acetyl-n-propyl (NAP)- and N-pivaloyl-i-propyl (NPP)-amino acid esters were evaluated for the determination of the 15N content of lysine and 16 other amino acids ranging from natural abundance to an enrichment of 0.6 APE 15N in a complex mixture of proteinogenic amino acids and several matrices. At natural abundances for all amino acids analysed, NAP and NPP derivatives gave mean precisions of 0.5 and 0.3/1000 delta 15N, respectively. The mean precision for NPP derivatives at enrichments between 0.42 and 1.10 AP 15N ranged between 1.0-15.0/1000 delta 15N. 15N from ammonium chloride was incorporated into lysine and in all other amino acids of serum albumin to a 2.5 times higher degree than from urea. Somewhat lower, but significant, lysine enrichments were detected in liver, duodenum and jejunum. After 10 days of ingestion of 15N-labeled urea a significant 15N enrichment in lysine of serum albumin could not be detected, although lysine in the ileal digesta was significantly labeled by day 5. This is the first report providing evidence that the microflora in the upper gastrointestinal tract of pigs is capable of synthesizing lysine de novo and that this lysine is available for body protein synthesis.

Convective warming combined with vasodilator therapy accelerates core rewarming after coronary artery bypass surgery

In a prospective, randomized, controlled study, we have investigated the effect of forced air warming on the rate of change of nasopharyngeal and rectal temperatures in 20 patients after coronary artery bypass grafting. All patients had nasopharyngeal temperatures less than 36 degrees C on arrival in the intensive care unit and received an infusion of glyceryl trinitrate 15 mg h-1, but none received inotropes. Ten patients were warmed under an aluminized plastic "space" blanket (control group) and 10 were warmed under a "Bair Hugger" blanket connected to its power unit on "high" setting (Bair Hugger group). The rates of increase in nasopharyngeal temperature were 0.4 and 0.95 degrees C h-1, respectively, in the control and Bair Hugger groups (P < 0.01) during the first 2 h after operation. Over the same period of time, rectal temperatures increased at a rate of 0.25 and 0.75 degrees C h-1 in the control and Bair Hugger groups, respectively (P < 0.01).

Central and NO mediated mechanisms are involved in the inhibitory effects of CCK on the chicken cecorectal area

In chickens CCK-8s induces defecation and causes an inhibition of rectal electrical activity (EA) and an increase in cecal motility. In contrast, CCK-4 inhibits the motility of both rectum and ceca. The cecorectal responses to CCK-8s and CCK-4, given intravenously (i.v.), were studied in conscious chickens prepared with electrodes for electromyography; the influence of atropine, phentolamine plus propranolol, hexamethonium and L-NAME on such responses was determined. Atropine and phentolamine plus propranolol did not cause any change in the response to CCK-8s or CCK-4 in the cecorectal area. Hexamethonium only induced a significant decrease in the number of defecations (ND) induced by CCK-8s. L-NAME slightly modified the decrease in rectal EA due to CCK-8s. The effects of intracerebroventricular (i.c.v.) administration of CCK-8s and CCK-4 were also studied. CCK-8s and CCK-4, given i.c.v., caused, in conscious chickens, a slight decrease in cecal EA, in the 15 minutes following administration. This effect was similar to that seen after i.v. administration of CCK-4. In conclusion, our results suggest that the inhibitory action of CCK on chicken rectum is mediated, at least in part, through nitric oxide release. In addition, nicotinic receptors mediate the increase in the ND caused by CCK-8s. Ganglionic, muscarinic, adrenergic and nitrergic blockade were not able to modify the excitatory cecal response to CCK-8s, which may indicate that the receptor mediating this effect is located on the cecal smooth muscle. Finally, the inhibitory action of i.v. CCK-4 on chicken cecum seems to be centrally mediated, as suggested by the fact that i.c.v. administration of either CCK-8s or CCK-4 induce a similar effect.

Renal compensation for cecal loss in Gambel's quail (Callipepla gambelii)

Some studies have implicated the avian digestive cecae as important sites of water and solute reclamation working in concert with the lower intestine and the kidneys as part of an integrated osmoregulatory system. In Gambel's quail (Callipepla gambelii), we studied compensatory adjustments in renal function on days 6-7 and 16-17 following ligation of cecae. Plasma osmolality (Posm) varied significantly between groups with sham-operated birds (Cs), with an average (Posm) of 348 mOsm/kg H2O and quail with ligated cecae (Cx) having a (Posm) of 355 mOsm/kg H2O. We detected no change in the rate of glomerular filtration (GFR) between experimental and control groups either shortly after cecectomy or after 16-17 d following surgery. Regression analysis of GFR and urine flow rate (V) showed that Cx birds had a significantly lower V at a given GFR than did controls, evidence that Cx quail absorbed more fluid in their renal tubules. Increased fluid reabsorption was apparently driven by an enhanced reabsorption of sodium. Indeed, sodium excretion was lower in Cx quail as compared to sham-operated birds. On days 6-7, Cx quail drank more water than Cs birds, but by days 16-17 drinking rates were similar. At the end of the experiments, Cx quail showed a proliferation of microvilli along the apical membrane of the rectum, an adjustment consistent with the idea that the rectum alters its absorption capacity to adjust for the loss of cecal function.

[A new approach of functional recto-anal exploration: the compliance of the rectum and the anal canal]

We have developed an original method of determining the rectal and the anal compliance. The rectum must serve as a fecal reservoir. This storage function requires that the rectum must be distensible. The anal canal must become easily looser for defecation. These features are not explored by the usual rectoanal manometric recordings. Very few investigations about the compliance are carried out. In our procedure, exploration balloons are connected via polyethylene tubes to pressure transducers, direct-writing electrical recorder and pump under the command of the computer. The pressure generated is as high as the distensibility is poor, as the compliance is decreased. The pressure/volume curve shows the compliance. The procedure is different for the rectum on the one hand, and for the anal canal on the other. The rectal device consists of a balloon at the end of the tube. It shall be inflated until only 60 ml., and then deflated at the same rythm, which is constant during each test. The first test takes place at the speed of 30 ml. per minute; so the inflation lasts 2 mn and the deflation the same time, afterwards the second test lasts one mn for each one, and finally the third one 40 seconds in the same way. For the anal canal, the balloon, ring shaped around the tube, measuring an inch in length, is inflated at only 12 ml. For the first test the inflation and deflation rate of speed is 3 ml per mn, afterwards 6 ml./mn then 9 ml./mn. and thereafter 12 ml./mn/; these series are done in randomized order. In both procedures, an additional relaxation test at the maximum of inflation takes place for 2 minutes. We have explored ten healthy volunteers and 120 patients suffering from various digestive diseases. The curves show the rectal compliance, and in the case of the anus a relaxation, which seems to be an active opening, occurs for a distension of 5-8 ml, i.e. 19-21 mn in diameter. In pathology, the excess of compliance is observed in patients with incontinence, whereas an inadequate compliance is seen in the dyschesia, descending perineum and prolapse, traumatic or surgical injuries, etc. This exploration will be a useful guide for the choice of the convenient treatment and the follow-up.

Thermal responses to light, moderate and heavy daily outdoor work in cold weather

Working in the cold is part of the normal routine in outdoor occupations in winter in the subarctic regions, but there are few data available on occupational exposure to cold during outdoor work. In the present study, thermal responses were measured in winter in Finland during 23 working days among young, healthy men working in heavy, moderate and light daily outdoor jobs. During the measurements ambient temperature ranged from +3 to -27 degrees C, air velocity from 0.2 to 4.3 m.s-1, and the subjects wore normal winter clothing. The skin temperatures measured often indicated disturbed performance, discomfort and a risk of adverse health effects, especially during the very cold days (ambient temperature less than -15 degrees C) in the light work. The most common problems were cooling of the extremities and the face and cool or cold sensations. The temperatures on the distal parts of the upper extremities correlated significantly with the heaviness of the work (r = 0.51, P = 0.014). The core temperature remained at the safety level in each case. Apart from clothing, an appropriate work load proved to be an effective way of keeping up the temperature of the extremities in cold work, and that should be taken into account when outdoor work is being planned.

Anorectal and pelvic floor function. Relevance of continence, incontinence, and constipation

Anorectal tests need to be tailored to the presentation of the individual patient. Clearly the tests are most useful when they identify anatomic or physiologic abnormalities for which there are successful treatments. For the incontinent patient, anal manometry is the most useful test. Sphincter injuries should be repaired, whereas neurogenic incontinence is best treated initially with biofeedback. Three tests are more useful for the constipated patient: colonic transit time, degree of pelvic floor descent on straining, and balloon expulsion. Colonic inertia responds to total colectomy and pelvic floor dysfunction to biofeedback. Meanwhile, patients with irritable bowel syndrome require rereferral back to their physicians.

Anorectal manometry before, during and after estrogen replacement therapy

The incidence of relaxation of the pelvic floor increases with age, and although a relation between prolapse and the decline of estrogens has been suggested, there is no objective evidence. Together with urodynamic measurements, anal manometry is one of the few ways of making an objective assessment of the strength of pelvic structures located in and near the pelvic floor. In order to study the role of estrogens, anal manometry was performed before, during and after estrogen replacement therapy with daily oral use of 0.625 mg conjugated estrogens for 6 months. Five postmenopausal women, who had not used estrogen replacement therapy in the past, were included in the study. None of the manometric parameters, including maximal anal resting pressure, maximal squeeze pressure and internal anal sphincter response, changed. It was concluded that estrogens have no effects on manometric parameters of the external sphincter and that anal manometry may not be the appropriate method to assess the effects of estrogens on the pelvic floor.

Motor activity of refashioned colorectoanus in patients with total colonic aganglionosis

An ano-recto-sigmoid colon pressure study was designed to evaluate the characteristics of the motor activity of refashioned colorectoanus in patients with total colonic aganglionosis (TCA) in comparison to patients with rectosigmoid Hirschsprung's disease (HD) and healthy children (HC), and to elucidate the pathophysiology of the pulled-through ileum, with aganglionic colon as an onlay patch, in coordination with the anal sphincter. The study group consisted of six patients with TCA, six with HD who underwent endorectal colonic pull-through, and six HC. Pressure studies were performed using a triple-lumen catheter; recording sites were 15 and 9 cm from the anal verge, and at the anal canal. The following were measured and compared: (1) anal canal pressure profile, (2) resting pattern of activity at the refashioned colorectum and anal canal, and (3) changes in motor activity after stimulation with cold water and glycerin. The motor activities of the refashioned colorectoanus of TCA and HD patients differed greatly from those of HC. All six HC had no isolated high-amplitude contraction (IHAC) in the colorectum during the 45-minute study period; they complained of a strong urge to defecate after glycerin enema and actually did so. In contrast, IHAC appeared 2.0 +/- 1.3 times per 10 minutes, with maximal amplitude of 60.3 +/- 24.9 cm H2O in TCA, and 5.6 +/- 3.7 per 10 minutes with maximal amplitude of 79.5 +/- 11.7 cm H2O in HD. After glycerin enema, IHAC increased to 0.5 +/- 0.2 per minute and 69.3 +/- 44.6 cm H2O in TCA and to 0.8 +/- 0.4 per minute and 93.0 +/- 12.8 cm H2O in HD. Defecation was postponed for more than 10 minutes in two HD and all TCA patients. The mean motility index per minute was least for TCA patients (76.9 +/- 98.2); it was 406.5 +/- 197.1 (P < .05) for HD patients and 159.2 +/- 84.2 (P < .01) for HC. TCA patients had the lowest amplitude of maximal resting anal pressure, and hypoactivity of the colorectum during rest and after stimulation; this suggests that motor dysfunction involves even the ganglionic ileum, concomitant with suppressed signals to the higher integrating center for defecation.

Analysis of prostate and seminal vesicle motion: implications for treatment planning

PURPOSE

To quantify prostate and seminal vesicle positional changes (target motion) between treatment planning and delivery, and to identify the factors contributing to target motion.

METHODS AND MATERIALS

Thirty patients with adenocarcinoma of the prostate were prospectively evaluated by analyzing two sequential planning computerized tomography (CT) scans (S1, obtained prior to treatment, and S2, obtained during the fourth week of treatment) for each patient. All anatomical volumes of interest (soft tissue and bony) were reconstructed from transverse CT images and projected onto anterior and lateral beam's-eye view projections. Positional changes between S1 and S2 were eliminated by applying a rigid body translation and rotation. Target motion was then measured by recording the positional change between S1 and S2 at the edges (right, left, superior, inferior). Potential correlation of target motion with bladder volume, rectal volume, and rectal diameter changes were evaluated by linear regression analysis.

RESULTS

Neither the prostate nor seminal vesicles remained fixed with respect to bony anatomy between S1 and S2. The distribution of positional changes were generally small (< 0.5 cm), but maximum displacements of 1.5-2.2 cm did occur, particularly in the lateral view. In this study, bladder volume changes between the scans were small and did not correlate with target motion (P = 0.67). Both rectal volume and rectal diameter changes correlated with target motion for both the prostate (p = 0.004 and 0.005, respectively) and seminal vesicles (p < 0.001 and < 0.001, respectively). However, neither the initial rectal volume nor the initial rectal diameter could be used to predict subsequent target motion when evaluated either singly or as part of a multiple regression model.

CONCLUSIONS

Target motion occurs during the course of treatment planning and delivery and should be considered when designing conformal radiation fields. Although the target position at the time of planning CT may differ substantially from the mean treatment position, target motion cannot be predicted by evaluating simply measured parameters from a single scan, or double scan sequence.

Sigmoido-rectal junction reflex: role in the defecation mechanism

The presence of a sphincter at the rectosigmoid junction (RSJ) is debated. This investigation studies the presence or absence of a sphincter and its possible role in sigmoid colon storage and rectal evacuation. Eighteen healthy volunteers (10 males, 8 females) with a mean age of 36.6 +/- 14.8 years (range 21-53) were studied. The pressure response of the sigmoid colon, RSJ, and rectum to sigmoid and rectal distension, respectively, was determined before and after anesthetizing either the sigmoid colon or the rectum. The RSJ length was evaluated by the station pull-through technique. Sigmoid distension with balloon volumes of up to 80.6 +/- 4.4 ml of H2O effected no sigmoid, RSJ or rectal pressure changes (P > 0.05). At a mean sigmoid distension of 88.6 +/- 4.1 ml of H2O, the sigmoid colon showed a significant pressure increase (P < 0.001), a RSJ pressure decrease (P < 0.05), and insignificant pressure changes in the rectum (P > 0.05); the balloon was dispelled into the rectum. Rectal distension of 94.6 +/- 5.8 ml of H2O produced rectal (P < 0.001) and RSJ (P < 0.05) pressure increases. Distension of the anesthetized sigmoid and rectum did not produce pressure changes in the RSJ (P > 0.05). This study demonstrated a high pressure zone at the RSJ of 3.8 +/- 0.7 cm in length. This suggests that the RSJ might act as a functional sphincter. It opens reflexly upon sigmoid contraction, by a reflex we call "rectosigmoid inhibitory reflex," and closes upon rectal contraction, a reflex we call "rectosigmoid excitatory reflex." The former allows the stored feces in the sigmoid colon to pass to the rectum, and the latter reflex prevents stool reflux to the sigmoid upon rectal contraction.

Physiology and pathophysiology of anal function

A review of the Danish contributions to the increased understanding of anorectal physiology and pathophysiology during the last 25 years is presented. In this period there has been a vast international increase in interest in anorectal physiology and pathophysiology, with much improvement in the understanding and treatment of anorectal functional disorders. The application of new sophisticated techniques to anorectal physiology research continues to improve our knowledge of anorectal function.

Rectal adaptation to distention: implications for the determination of perception thresholds

Chronic changes in rectal compliance and perception are often associated with constipation, but the mechanisms responsible for these changes are not known. These studies evaluated the dynamic response of the rectal wall to distention and, in a separate investigation, the influence of adaptive relaxation on perception thresholds. In Study 1, seven healthy volunteers were evaluated using a computer-controlled barostat to maintain continuous isobaric distention of the rectum at urge threshold over a 25-min period. Changes in intrabag volume were evaluated at minutes 1, 5, and 25. Study 2 investigated changes in perception thresholds with different interstimulus intervals (30 s vs. 60 s) in 16 healthy subjects. Pressure was incremented in steps of 2 mmHg up to discomfort threshold. The mean intrabag volume, pressure, and the compliance index for the first and second 5-s intervals were compared to the last 5 s interval. Statistical analyses were performed using the Wilcoxon Sign-Rank test with Bonferonni corrections. Study 1 showed a significant relaxation of the rectal wall in response to balloon distention with volumes consistently increasing from minute 1 to minute 25. Study 2 showed a significant change in the compliance index at the threshold for moderate urge and intense urge during the 60-s distention that resulted from progressive relaxation of the rectal wall. Study 1 showed an adaptive response of the rectum to distention. Study 2 confirmed these findings and implied a role for this adaptive response in the determination of rectal sensory thresholds.

Latency measurement of rectoanal reflexes

PURPOSE

Latency values of rectoanal reflexes may be altered in disorders of the pelvic floor. Evaluation of this relatively uninvestigated aspect of rectoanal reflexes may have diagnostic implications in patients with disorders of defecation.

METHODS

We studied the latency of rectoanal inhibitory and excitatory reflexes to sequential balloon distention of the rectum with 60 ml and 120 ml of air in 14 normal controls (mean age, 41.5 (range, 19-66) years), in 14 patients with fecal incontinence (FI) (mean age, 44.2 (range, 28-72) years), and in 14 patients with slow transit constipation (STC) (mean age, 40.6 (range 22-68) years).

RESULTS

The mean latency of inhibition (FI = 5.3 seconds; STC = 4.6 seconds; controls = 5.1 seconds) was remarkably similar for the three groups (P = 0.19). The mean latency of excitation in the proximal anal canal (FI = 2.8 seconds; STC = 2.5 seconds; controls = 2.8 seconds) was comparable in the three groups (P = 0.58). The mean latency of excitation in the distal anal canal (FI = 4.8 seconds; STC = 2.6 seconds; controls = 2.7 seconds) was prolonged in patients who were incontinent compared with the other two groups (P < 0.01).

CONCLUSIONS

Proximal rectoanal excitation and inhibitory reflexes, when present, have a constant latency, irrespective of the underlying condition. The different latency values for proximal and distal rectoanal excitatory reflexes in patients with FI may indicate disparate denervation damage to the external anal sphincter.

Attenuation of c-Fos expression in the rat lumbosacral spinal cord by morphine or tramadol following noxious colorectal distention

We have previously reported that repetitive, noxious colorectal distention (CRD) induces c-Fos in the lumbosacral spinal cord. This study examined the effects of the analgesics morphine and tramadol on c-Fos expression resulting from noxious CRD in the rat. Pre-treatment (30 min or 1 min, i.v.) with morphine (1.25 mg/kg-5.0 mg/kg) or tramadol (1 mg/kg-20 mg/kg) dose-dependently attenuated c-Fos expression to CRD in all areas of the L6-S1 spinal gray matter. The highest dose of morphine was equipotent to the highest dose of tramadol. Repetitive dosing (1/4 of the greatest dose every 30 min) was as effective as a single bolus dose for both drugs. The visceromotor response to CRD was dose-dependently attenuated by tramadol and was reversed by naloxone. However, the dose of tramadol that eliminated the visceromotor response (7% of control) reduced the c-Fos expression to 47% of control. These results demonstrate that these two analgesics attenuate immediate-early gene expression and the visceromotor response to a noxious visceral stimulus and suggest that complete attenuation of c-Fos expression is not necessary for these compounds to produce analgesia to a noxious visceral stimulus.

Octreotide reduces perception of rectal electrical stimulation by spinal afferent pathway inhibition

Octreotide reduces perception of rectal distension in normal volunteers and irritable bowel patients. To localize octreotide's site of action, perceptual and evoked potential responses to rectal electrical stimulation were tested in seven normal volunteers after double-blind octreotide (100 micrograms 2) or placebo. After octreotide, the currents needed to elicit threshold perception of square-wave impulses delivered to the rectum were 29% higher than after placebo. When electrical stimulation was delivered at constant currents 50% above threshold, rectal perception scores were significantly reduced after octreotide compared with placebo. Rectal electrical stimulation led to characteristic and reproducible cerebral evoked potentials. Octreotide had no effect on latencies, but reduced peak-to-peak amplitudes by 35% compared with placebo. Rectal electrical stimulation also led to characteristic and reproducible spinal evoked potentials. Octreotide had no effect on spinal latencies, but reduced peak-to-peak amplitudes by 51%. In conclusion, octreotide reduces perception of rectal electrical stimulation, which is associated with inhibition of cerebral and spinal evoked potential amplitude, indicating effects on spinal afferent pathways.

Effects of cecal ligation and colostomy on motility of the rectum, ileum, and cecum in turkeys

Motilities of the rectum, ileum, and ceca were examined in surgically prepared turkeys by using strain gauge transducers implanted on these sites after cecal ligation or colostomy. All birds were provided ad libitum access to feed and water throughout the study. Cecal ligation increased the frequency of small anti-peristaltic contractions in the proximal (P < .01) and distal (P < .05) rectum and the frequency of defecations (P < .05) compared with intact controls. Cecal ligation decreased the frequency of single contractions in the proximal ileum (P < .05) and that of all contractions in the distal ileum (P < .05), and ligation (P < .01) and colostomy (P < .05) increased the frequency of single contractions in the distal site. However, major and minor cecal contractions were not affected by colostomy in the proximal and distal cecum. The results suggest that the effects on contractile activities of the hindgut must be considered when interpreting responses to cecal ligation and colostomy.

Effect of different ambient temperature and lipopolysaccharide administration on the circadian rhythm of rectal temperature and hypothalamic PGE2 production in aged male rats

Old and young male rats (22 and 7 months respectively) were exposed to ambient temperatures of 4, 22, 27 and 35 degrees C. The rats' rectal temperatures (RTs) were measured periodically, after exposure to the varying temperatures at different hours during the day. The mean circadian value of RTs in the aged rats was different from that of the young rats. Whereas exposure to low temperatures caused a decrease of 2.0 degrees C in the RTs of the old rats, exposure to heat (35 degrees C) caused an increase of 1 degree C in their RTs. An injection of 200 micrograms (intraperitoneally) of E. coli lipopolysaccharide caused them to experience a long period of hypothermia. Elevation in the RTs after the hypothermic period ended was significantly lower in the old rats. However no significant differences in hypothalamic PGE2 production were to be found between the old and young groups 24 h after pyrogen administration.

[Comparison of temperatures from 7 points in the patients under intraperitoneal hyperthermic perfusion]

We measured the temperatures from 7 points in the patients under intraperitoneal hyperthermic perfusion (IPHP), associated with induced hypothermia. The temperatures from the 7 points were as follows, pulmonary artery blood temperature (PAT), bladder temperature (BT), sole deep body temperature (ST), forehead deep body temperature (FT), external aural cannal temperature (EAT), esophageal temperature (ET), and rectal temperature (RT). We studied the relationship between PAT and the other 6 temperatures. During IPHP, DT rose up to nearly 40 degrees C, and we considered it very useful to judge the temperatures of the other intra-abdominal organs, which were in contact with the perfusate of IPHP. Judging from the difference of PAT and ST, ST was found useful to estimate the degree of insufficiency of the peripheral circulation. We calculated the correlation coefficients with PAT among the four points, and the order of the correlation coefficients was EAT > ET > FT > RT. EAT showed the highest correlation coefficient with PAT (r = 0.981), and we considered EAT can be a substitute for PAT during IPHP. ET also showed a high correlation with PAT (r = 0.959), but it showed an unusual rise in a case of hydrothorax with hot perfusate for IPHP. Therefore, ET cannot be used solely as a substitute for PAT, but ET can be used as a marker to find a complication of IPHP, hydrothorax.

Oxymorphone-induced analgesia and colonic motility measured in colorectal distension

Changes in colonic motility in rats following intravenous (IV) oxymorphone (0.1 mg/kg), atropine (0.1 mg/kg), or saline were monitored to determine whether opioid-induced changes in colonic motility affect antinociceptive measurements when using colorectal distension (CRD) as a nociceptive assay. Polygraph recordings of colonic pressures, contraction frequencies, and the pressure-volume relationship of the stimulus showed that oxymorphone produced a transient increase in contraction frequencies when compared to atropine- and saline-treated rats. The transient increase in contraction frequency caused by oxymorphone declined to baseline levels at 30 min after administration, the time at which the nociceptive threshold for CRD was tested. Neither oxymorphone nor atropine changed baseline pressures or the pressure-volume curve for the balloon stimulus. Antinociceptive results from CRD at 30 min posttreatment showed that only oxymorphone produced significant antinociception. We conclude that oxymorphone does not produce changes in colonic motility that complicate antinociceptive measurements in CRD and that CRD is an effective means of testing opioid-induced visceral antinociception.

Factors affecting rectal temperature in infancy

The recordings of 1197 overnight rectal temperatures from infants of up to 24 weeks of age have been analysed with respect to 12 variables, including a number of risk factors for sudden infant death syndrome. Multivariable regression was used to identify if parental smoking, bottle feeding, sleeping position, and birth weight affect the overnight rectal temperature of infants. The rectal temperature, averaged over the period from three to five hours after the infants were put to bed, correlated well (R = 0.36) with the collected variables. An increase in the infant's age, birth weight, and the supine sleeping position all decreased the night time rectal temperatures. However, an increase in the night time room temperature, weight, and the combination of bottle feeding and parental smoking produced an increase in rectal temperature. The individual effects of bottle feeding and parental smoking were not significant. The results show that some of the major risk factors have the effect of raising the rectal temperature of sleeping infants.

Water and electrolyte homeostasis in sheep without functional colons

The regulatory role of the colon in water and electrolyte balance and the renal compensation which follows impairment of colonic function were assessed using sheep with ileorectal anastomosis (ILRAN sheep) on restricted and free water intake as experimental models. Faecal electrolyte loss sustained by the ILRAN group was eight to nine times greater than that in the control animals. When water was available ad lib., ILRAN sheep lost 2.81 and 0.51 more water per day via the faeces and urine, respectively, than the controls. Urine volume in the ILRAN sheep comprised largely electrolyte-free water and the renal retention of water was entirely secondary to the high degree of sodium reabsorption in these animals compared with the controls. On restricted water intake, the urine volume of the ILRAN sheep declined due to retention of electrolyte-free water and even greater absorption of sodium (and hence water by osmosis) by the kidney tubules. The latter observation was substantiated by a decrease in fractional excretion of sodium from 0.29 to 0.08% when water intake was restricted. Plasma aldosterone concentration was markedly elevated in the ILRAN sheep as a result of the excessive loss of sodium and water via the faeces. Activation of the renin-angiotensin-aldosterone sequence is believed to underlie the increased sensation of thirst (ILRAN sheep drank on average about 2.51 more water per day than the controls), the homeostatic response by the kidneys and the relatively lower plasma potassium in the ILRAN sheep compared to controls.