Continent colonic conduit for rectal evacuation in severe constipation

We describe a new operation for the treatment of rectal evacuatory disorders: a continent colonic conduit, incorporating an intussuscepted valve, was constructed from the sigmoid colon. Intubation of the conduit allowed irrigation and evacuation of the distal colon and rectum. Initially all 10 patients reported a reduction in time taken and the discomfort involved in completing evacuation. The number of stools passed per week increased in 9 out of 10 patients, from a median of 1.5 (range 0.25-7) to a median of 7 (range 3-7) postoperatively. Subsequently, 3 patients developed complications, 2 of whom required conversion to an ileostomy. Overall, the colonic conduit procedure was successful in treating the rectal evacuatory disorder in 7 patients, failed in 2, and 1 patient has a temporary defunctioning ileostomy. The procedure is a relatively simple surgical alternative for the treatment of a condition which is often resistant to conservative measures.

Continent colonic conduit for the treatment of faecal incontinence associated with disordered evacuation

A transverse colonic conduit incorporating an intussusception valve and skin-flapped cutaneous aperture was constructed in nine patients with combined faecal incontinence and disordered evacuation. Intestinal continuity was restored with a colocolonic anastomosis. Median follow-up was 4 (range 2-15) months and daily irrigation with a median of 1.2 (range 0.3-2.0) litres of water resulted in evacuation in less than 1 h. At 1 month after operation there was no leakage of solid or liquid faeces from the anus between irrigations. The valve was continent to faeces and irrigation fluid, and no stoma appliances were required.

Electrically stimulated colonic reservoir for total anorectal reconstruction

Total anorectal reconstruction after abdominoperineal excision of the rectum has failed to achieve perfect continence. Electrically stimulated reservoir evacuation in combination with an electrically stimulated gracilis neoanal sphincter might improve results. A J pouch was constructed in an isolated colonic loop of seven dogs. Bipolar square wave pulses were delivered via two intramural stainless steel electrode pairs at 10 Hz. Stimulation parameters were varied to achieve adequate contraction. Serosal strain gauges recorded spontaneous and stimulated pouch motility. Evacuation was quantified by a volume displacement technique and observed fluoroscopically. Recordings were performed for a median of 3 (range 1-11) months. At 10 Hz and 0.5 ms pulse width, stimulation was required for 2 min and at voltages of 15 V (n = 4), 18 V (n = 1) and 20 V (n = 2) to obtain a contraction of amplitude comparable to that of a spontaneous contraction. Suprathreshold stimulation invariably resulted in colonic pouch contraction. The mean(95 per cent confidence interval (c.i.)) stimulus-response latency was 25.5(1.9) s. The mean(95 per cent c.i.) intraluminal pressure generated during stimulation was 114.1(17.0) cmH2O and 64.6(12.0) cmH2O during spontaneous activity (P < 0.001). In conclusion, electrical stimulation via intramural electrodes produced contraction generating sufficient intraluminal pressure to effect evacuation of a canine colonic pouch. This has potential for incorporation with an electrically stimulated neoanal sphincter in total anorectal reconstruction to improve evacuation and continence.

Role of leucocytes in damage to the vascular endothelium during ischaemia-reperfusion injury

During this investigation, a model of tourniquet-induced forearm ischaemia-reperfusion injury is employed to investigate the role of leucocytes in damage to the vascular endothelium during ischaemia-reperfusion injury. Leucocyte entrapment is investigated by measuring the concentration of leucocytes in venous blood leaving the arm. Neutrophil and monocyte leucocyte subpopulations are isolated by density gradient centrifugation techniques. Cell surface expression of CD11b and the intracellular production of hydrogen peroxide are measured via flow cytometry. Plasma concentrations of elastase and von Willebrand factor (vWF) are measured using enzyme-linked immunosorbemt assay (ELISA) techniques. During ischaemia-reperfusion, there was an increase in CD11b cell surface expression on neutrophils (P=0.040) and monocytes (P=0.049), and a decrease in peripheral blood leucocytes (P=0.019). There was an increase in the intracellular production of hydrogen peroxide by leucocyte subpopulations (P=0.027 [neutrophils], P=0.091 [monocytes]) and in the plasma elastase concentration (P=0.05). There was also a trend to increasing plasma concentration of vWF (P=0.0562), which was measured as a marker of endothelial damage. Ischaemia-reperfusion results in increased adhesiveness, entrapment and activation of leucocytes. Even following a mild ischaemic insult, this leucocyte response was followed immediately by evidence of endothelial damage. These results may have important implications for understanding the development of chronic diseases that involve mild ischaemic episodes.

Review of Parameters Influencing Hydraulic Forces on Centrifugal Impellers

Both radial and axial hydraulic forces act on the impeller of a centrifugal pump. The radial forces are due to three different mechanisms: (a) radial thrust due to non-uniform pressure distribution around the impeller, (b) labyrinth forces and (c) impeller-diffuser interaction forces. The nature, size and origin of these forces are discussed. Steady radial thrust depends on the specific speed of the pump, type of casing (single or double volute, diffuser), geometric parameters and operation conditions including cavitation. The impact of these factors on radial loads is demonstrated and quantitative data are presented. Four different methods for radial thrust measurements are presented.

Axial thrust on pump impellers is extremely sensitive to tolerances and to the labyrinth flowrate. Two methods for predicting axial thrust are discussed and predictions are compared to measurements on a multi-stage boiler feed pump. A number of parameters influencing axial thrust are treated.

Use of human cumulus granulosa cells for in vitro screening of reproductive toxicants

We investigated the possibility that human granulosa cells from the cumulus mass obtained during human in vitro fertilization/embryo transfer (IVF/ET) might be useful for screening of potential reproductive toxicants in vitro. The cumulus granulosa cells detached from the zona pellucida after fertilization were allowed to spontaneously adhere to the incubation dish following transfer (removal) of the embryo. These cumulus cells survived in culture for at least four additional days, appeared on simple inspection to be morphologically normal luteinized granulosa cells, and produced large amounts of progesterone (P) over the culture interval. Production gradually declined during culture in the absence of human chorionic gonadotropin (hCG); however, inclusion of hCG (100 ng/mL) in the medium maintained P production at control (day 1) levels. Introduction of estrogenic agents previously shown to suppress P production in porcine or human culture systems using mural granulosa cells showed comparable effects in this human cumulus cell system. 17 beta-estradiol (10(-5) M), clomiphene citrate (10(-5) M), and o,p-DDT (10(-5)) significantly inhibited hCG-supported P production by human cumulus cells in vitro. This system has the advantages that (1) human cumulus granulosa cells are readily available from IVF/ET programs, (2) the techniques for maintaining the cells in culture are extremely simple, (3) a marker of highly differentiated granulosa cell function (P production) can be reliably measured, and (4) the cells respond predictably like other comparable granulosa cell systems. We conclude that human cumulus cells are a readily available and useful resource for in vitro screening of potential female reproductive toxicants.

Adrenoceptors and colocolonic inhibitory reflex

The colocolonic inhibitory reflex is characterized by inhibition of proximal colonic motility induced by distal colonic distension. The aim of this study was to investigate the underlying neural mechanisms of this reflex, in vivo, using an isolated loop of canine colon. In five beagle dogs, motility was recorded from an exteriorized colonic loop via a serosal strain gauge connected to a digital data logger and chart recorder. Inflation of a balloon in the distal colon resulted in inhibition of motility in the isolated loop. Inhibition of motor activity persisted following injection of propranolol (100 microg/kg intravenously), a beta-adrenoceptor antagonist, but was abolished following administration of the alpha2-adrenoceptor antagonist yohimbine (200 microg/kg intravenously). This study confirms that the colocolonic inhibitory reflex is mediated via the extrinsic nerves to the colon. As the reflex was abolished by alpha2-, but not beta-adrenoceptor blockade, this indicates that the reflex pathway involves alpha2-adrenoceptors.

Screening of potential reproductive toxicants by use of porcine granulosa cell cultures

While approximately 60 000 chemicals are in widespread use with 1000 new chemicals introduced into the environment each year, the biologic effects of these agents are poorly understood. With the specific goal of testing for potential reproductive toxicity, we have established methodology for the screening of compounds in vitro by measuring effects on progesterone production by porcine granulosa cells in culture. Granulosa cells were harvested by mechanical agitation, cryopreserved, and cells with known progesterone production capacity utilized for culture. Agents to be tested were added to cultures of 10(5) cells and the media assayed for progesterone by radioimmunoassay. Estradiol suppression of progesterone production was easily demonstrated in this system and utilized as a verification of responsiveness. The pesticide o,p-DDT and its isomer p,p-DDT produced dramatic suppression of progesterone production apparently with equal potencies to estradiol. By contrast, the pesticides malathion, parathion and dieldrin and the fungicide hexachlorobenzene were without effect in this test system.

Effect of heart rate increase on dorsal aortic flow before and after volume loading in the stage 24 chick embryo

In the stage 24 chick embryo, a paced increase in heart rate reduces stroke volume, presumably by rate-dependent decrease in passive filling. We hypothesized that rate-dependent stroke volume reduction could be abolished by volume loading. Dorsal aortic blood velocity was measured with a 20 mHz pulsed-Doppler meter from a 0.75-mm piezoelectric crystal (eight embryos), and atri-oventricular velocity was simultaneously measured from the ventricular apex (six embryos). Sinus venosus pacing (stimuli of 1 ms duration and less than 4 mA) was performed at intrinsic rate (P:I) and at 150% of intrinsic rate (P:150%I). Volume loading was performed during P:150%I by intravenous injection of 7.5 microL of chick Ringer's solution. Using atrioventricular velocity profile, stroke volume was divided into the proportion due to passive (E-phase) and active (A-phase) filling. Stroke volume was compared during P:I, P:150%I, immediately (P:150%I') and 30 s after (P:150%I") volume loading. Data (mean +/- SEM) were compared by ANOVA. During pacing, stroke volume (mm2/cycle) decreased but increased after volume loading (I, 0.43 +/- 0.03; P:I, 0.37 +/- 0.03; P:150%I, 0.19 +/- 0.03; P:150%I', 0.24 +/- 0.05; P:150%I", 0.28 +/- 0.04 (p less than 0.005). During P:150%I, E-phase filing disappeared and was not restored by volume loading, whereas, A-phase filling diminished but was restored by volume loading. In stage 24 chick embryos, rate-dependent stroke volume decrease is reversed by volume loading that restores stroke volume due to an increase in active filling but not passive filling. Thus, even at rapid heart rate, the embryonic ventricle responds to volume loading, indicating that the Frank-Starling relationship functions during tachycardia in the embryonic heart.

Proximal Resection Margin in Ivor-Lewis Oesophagectomy for Cancer

OBJECTIVE

The purpose of this study was to investigate whether a long proximal oesophageal resection margin (PRM) is associated with improved survival after oesophagectomy for cancer and to identify the optimal margin to aim for in this patient group.

METHODS

A prospectively maintained database identified 174 patients who underwent Ivor-Lewis oesophagectomy for cancer. Demographic, clinical, and pathological data were collected. X-tile software was used to identify the optimal resection point. Two models were analysed: single point resection with comparison of two groups (short and long), and two resection points with three groups (short, medium, and long) to provide a range.

RESULTS

The median PRM was 4.0 cm (interquartile range: 2.5-6.0 cm). After adjustment for significant confounders, multivariable Cox PH analysis demonstrated that the optimal resection margin was 1.7 cm, and in the three-group analysis the optimum PRM was between 1.7 and 3 cm. In the two-group analysis, the long margin had no effect on DFS (p = 0.37), but carried a significantly improved overall survival (hazard ratio [HR] = 0.46, 95 % confidence interval [CI] 0.25-0.87, p = 0.02). In the three-group analysis, the medium and long groups had improved OS compared with the short group (on average 54 %, HR ≥ 0.45, p ≤ 0.04). The 5-year disease-free and overall survival rates were highest in the medium PRM group (48 and 57 % respectively).

CONCLUSIONS

Optimal survival following oesophagectomy for cancer is achieved with a PRM > 1.7 cm, but a PRM > 3 cm does not yield a further survival advantage. Thus, the optimal PRM is likely to be between 1.7 and 3 cm.

Heart rate-dependent characteristics of diastolic ventricular filling in the developing chick embryo

The contributions of the early (passive) and late (active) components of ventricular filling have been reported to decrease and increase, respectively, during chick embryo cardiac development. We hypothesized that the observed changes in ventricular filling during early cardiac development results from a decrease in cycle length. We studied the effect of development and cycle length on atrioventricular inflow in 28 chick embryos, Hamilton-Hamburger stages 17, 24, and 26. Cycle length was perturbed (range 240-1040 ms) in ovo by transiently heating or cooling the sinus venosus. Atrioventricular inflow and dorsal aortic velocities were obtained by 20-MHz pulsed Doppler flow-meter and digitally recorded at 500 samples per second. Stroke volume was calculated from dorsal aortic velocity and cross-sectional area. The atrioventricular inflow wave form was integrated and partitioned by area and percentage of total into early (passive) and late (active) components using three methods. Regardless of method, the proportion of filling volume due to the early and late components was cycle length and stage dependent (p < 0.05). The early and late filling volumes were large in the older embryos, and during cycle length decrease (heart rate increase) the early filling volume decrease was greater than the late filling volume decrease. When compared with the percentage of intrinsic heart rate, the percentage of stroke volume due to early filling decreased as heart rate increased and was greater in younger embryos at all heart rates. That due to late filling increased as the percentage of intrinsic heart rate increased. Ventricular filling characteristics are both developmentally determined and cycle length dependent.

Interleukin-17 Expression in the Barrett's Metaplasia-Dysplasia-Adenocarcinoma Sequence

Introduction. This pilot study evaluated the expression of the proinflammatory cytokine IL-17 along the Barrett's metaplasia-dysplasia-adenocarcinoma sequence by establishing the expression levels of IL-17 in columnar epithelium, intestinal metaplastic cells, and dysplastic/glandular neoplastic cells. Immunohistochemical techniques were used to examine the accumulation of the proinflammatory cytokine IL-17 in forty (n = 40) formalin-fixed, paraffin-embedded oesophageal archived specimens across a range of endoscopic diagnostic categories, and a highly significant difference was found, where P ≤ 0.001, in IL-17 expression (Kruskall Wallis and Mann-Whitney U) between all the cell types examined. There was also a strong positive correlation (Spearman's rank correlation) between disease progression and IL-17 expression (r_s = 0.883, P < 0.001, n = 29), IL-17 expression was absent or absent/weak in columnar epithelium, weak to moderate in columnar metaplastic cells, and moderate to strong in dysplastic/neoplastic cells, which demonstrated that the elevation of IL-17 expression occurs in the progression of the disease. Understanding the differential expression of IL-17 between benign and malignant tissue potentially has a significant diagnostic, prognostic, and therapeutic value. Ultimately, this selective biomarker may be employed in routine clinical practice for the screening of oesophageal adenocarcinoma.

Effects of acetaminophen and nonsteroidal anti-inflammatory drugs on progesterone production by porcine granulosa cells in vitro

We investigated the effects of a group of pharmaceutical agents commonly ingested by reproductive-aged women, acetaminophen and the nonsteroidal anti-inflammatory drugs (NSAID), on progesterone (P) production by cultures of highly differentiated porcine granulosa cells. These compounds were added to cultures over a dose range of 10(-8) to 10(-5) M and P, and cell protein was measured after 24 hours. P production was suppressed by acetaminophen, fenoprofen, and sulindac to a maximum of 81%, 76%, and 71% of control, respectively. P production was enhanced by butazolidin at all doses tested to a maximum of 140% of control. Granulosa cell protein was suppressed by butazolidin and salicylic acid to a maximum of 81% of controls. These data imply that acetaminophen and several NSAID have the potential for clinical reproductive toxicity with differing individual effects on reproductive tract tissues, suggesting further selective testing in vivo.

The effect of cardiac cycle length on ventricular end-diastolic pressure and maximum time derivative of pressure in the stage 24 chick embryo

We hypothesized that developmental increases in both ventricular end-diastolic pressure (EDP) and the maximum time derivative of pressure (dP/dt) observed in stage 12 to 29 chick embryos are the result of observed cardiac cycle length (CL) decrease (heart rate increase). To test this hypothesis, we evaluated EDP and dP/dt changes that occur during acute CL alterations in the Hamburger-Hamilton stage 24 chick embryo (n = 18). Ventricular pressure measurements were obtained with a servo-null pressure system and digitally recorded at 500 samples/s. A 1-mm steel probe, heated (decrease CL) or cooled (increase CL), was applied to the sinus venosus. The average baseline CL was 454 ms. The heart rate perturbation resulted in CL that varied over a range of 200-2966 ms, assimilating the range of CL change observed during development. Changes in EDP ranged from 0.014 to 0.130 kPa (baseline = 0.061 kPa) and maximum dP/dt ranged from 0.33 to 13.33 kPa/s (baseline = 5.99) kPa/s). In each study, EDP varied directly with CL (R2 = 0.70). Conversely, maximum dP/dt changes were inversely related to CL alterations (R2 = 0.54). Thus, we found that there is a direct relationship between changes in CL and EDP in the stage 24 chick embryo, whereas CL and dP/dt vary inversely. During cardiac development, observed increases in maximum dP/dt may be attributed to CL decreases. In contrast, developmental increases in EDP cannot be explained by CL decrease and must be accounted for by maturational changes in cardiac function in the chick embryo.

Synthetic estrogens suppress granulosa cell progesterone production in vitro

We evaluated the effect of commonly used pharmaceutical estrogens and zeranol, an estrogenic growth-promoting agent used in livestock, on progesterone (P) production by cultures of highly differentiated porcine granulosa cells (GC). The compounds were added to GC cultures over a dose range of 10(-8) to 10(-5) M with P and cell protein measured after 24 h. P production was suppressed by estradiol (minimal suppressive dose: 10(-7) M; maximal suppression to 11% of control), ethinyl estradiol (10(-7) M, 15%), diethylstilbestrol (10(-5) M, 72%), clomiphene citrate (10(-6) M, 30%), nafoxidine (10(-7) M, 33%), tamoxifen (10(-6) M, 37%), and zeranol (10(-5) M, 83%). P production was not suppressed by mestranol. GC protein was suppressed by estradiol, ethinyl estradiol, nafoxidine, and zeranol. These data suggest that synthetic estrogens have the potential to suppress luteal P production by a mechanism unrelated to the usual measures of estrogenicity.

Relationship between cardiac cycle length and ventricular relaxation rate in the chick embryo

We hypothesized that during chick embryo cardiac development, cycle length decrease (heart rate increase) may be associated with developmental changes in the ventricular relaxation rate constant, tau, which can be estimated from ventricular pressure decrease by the function P(t) = P0e-t/tau, where P0 = pressure at the time of minimum time derivative of ventricular pressure and t = time. Natural logarithm conversion results in a linear relation between In P(t) and t with slope of -1/tau. We determined tau in Hamburger-Hamilton stage 17-27 (d 3-5) embryos (n = 35) at intrinsic cycle length and in stage 24 embryos (n = 5) during cardiac cycle length perturbations with the hot-cold probe technique. Regression analysis of In P(t) from the minimum dP/dt until t = 30 ms was used to estimate tau. Intrinsic cycle length decreased during development from stage 17 to 27 and tau decreased linearly as cycle length decreased (r = 0.39, p less than 0.005). Thus, during early development, both tau and cycle length decrease (relaxation rate and heart rate increase). In stage 24 embryos, cycle length perturbation yielded a nonlinear cycle length-dependent relation with tau, with a plateau at cycle lengths less than intrinsic, i.e. tau decreased with cycle length decrease to intrinsic cycle length, then tau plateaued with further cycle length decrease. These findings demonstrate that ventricular relaxation rate is both maturation and cycle length dependent. The plateau effect of the tau-cycle length relationship may be due to developmental limitations of the calcium transport system.

Fungal ball of the oesophagus

Candidal colonization of the gastrointestinal tract is common, but localized complications are rare. A case of an oesophageal fungal ball is described.

Thorn-induced granuloma of the medial cuneiform

A lytic lesion of the medial cuneiform of a 10-year-old boy was explored surgically, and a date palm thorn was identified. Histology revealed an aseptic granuloma. Even in the absence of a definite history of trauma, an organic foreign body lesion should be considered in the differential diagnosis of a lytic lesion of bone.

Ventricular relaxation in the stage 24 chick embryo following changes in volume and blockade of Na+ and Ca2+ channels

OBJECTIVE

Early in cardiac development, regulation of cytosolic Ca2+ has been thought to depend primarily on sarcolemmal Ca2+ transport. We hypothesized that perturbation of cytosolic Ca2+ in the embryonic ventricle would result in a change in ventricular relaxation which could be quantified by a monoexponential model. We reasoned that since it has been difficult to selectively block the Na(+)-Ca2+ exchanger in vivo, that blockade of Na+ (lidocaine) or Ca2+ (verapamil) channels in the embryonic heart may perturb cytosolic Ca2+ and thereby alter ventricular relaxation.

METHODS

All studies were performed in ovo in Hamilton-Hamburger stage 24 chick embryos. Isovolumic relaxation time (mean +/- standard deviation, 58 +/- 19 ms) was derived from dorsal aortic flow and atrioventricular inflow during 61 cardiac cycles in 4 embryos. Ventricular pressure was digitally recorded from 13 embryos during 188 cycles following intravenous injection of chick Ringer's solution (5 embryos), verapamil (4 embryos) or lidocaine (4 embryos). Ventricular relaxation was characterized by a monoexponential model: P(t) = P infinity + Poe-1/tau where P(t) = pressure at time (t), P infinity = pressure asymptote, Po = pressure at the onset of relaxation and tau = the isovolumic relaxation constant. Non-linear least-squares regression was used to estimate tau and P infinity during isovolumic relaxation at baseline and at 30 s and 60 s post-injection.

RESULTS

Ventricular end-diastolic pressure was increased by all three interventions. Both lidocaine and verapamil prolonged cycle length. Lidocaine prolonged tau while chick Ringer's solution and verapamil did not. No significant change in P chi was observed.

CONCLUSIONS

This study demonstrates that blockade of Na+ channels with lidocaine slows ventricular relaxation presumably by perturbing cytosolic Ca2+ via the Na(+)-Ca2+ exchange system. Changes following Ca2+ channel blockade with verapamil are less evident in the stage 24 chick embryo. Evaluation of ventricular relaxation may provide a useful way to study developmental aspects of Ca2+ transport.