Enterocutaneous fistula: A reconstructive dilemma

Summary  Surgical repair of enterocutaneous fistulae in Crohn’s disease may result in large skin defects of the anterior abdominal wall. We present a case in which a large defect was managed with reconstruction using a pedicled rectus abdominis mycocutaneous flap in a single procedure. The case highlights the technical challenge of such a case and the value of a joint surgical approach between plastic and colorectal services.     

Differential effects of kindling and kindled seizures on place learning in the morris water maze

There is some controversy about the role of long-term potentiation (LTP) in spatial learning. The authors have found that triggering generalized kindled seizures with stimulation of the perforant path disrupts spatial learning in the Morris water maze but that kindling per se does not affect spatial learning. It is suggested that abnormal electrical activity induced by high-frequency stimulation of the perforant path may have been responsible for the disruption of spatial learning previously attributed to LTP saturation.     

Management of patients supported on the Hemopump cardiac assist system

The Hemopump Cardiac Assist System is a relatively new intraarterial, axial-flow circulatory assist device that offers temporary left ventricular support to patients in refractory cardiogenic shock, without requiring major surgery for insertion. Use of the Hemopump is associated with a low complication rate. Device-related morbidity is extremely rare. Because the Hemopump is safe for use in community hospitals, the number of patients supported by this device is expected to increase. In this report, we present general guidelines for the care of patients supported by the Hemopump. We describe techniques for the management of afterload reduction, supravalvular dislodgement, device malfunction, ventricular ectopy, intracardiac shunting, and inflow cannula obstruction.     

Mode and speed specificity of eccentric and concentric exercise training

This research was supported by a Duke University Research Council Grant. The purpose of this study was to examine mode and speed specificity of strength training by comparing concentric and eccentric isokinetic exercise of the quadriceps. Forty-eight healthy men (mean age = 23.9 years) were randomly assigned to one of three groups: concentric training (C), eccentric training (E), or control (K). Average force (in Newtons) of 3 concentric and of 3 eccentric quadriceps contractions on the KIN-COM(R) dynamometer at 60, 120, and 180 degrees /sec was evaluated prior to and following a 6 week period during which only the C and E groups trained. Training sessions (3/week) included 4 submaximal and 1 maximal warm-up followed by 10 maximal effort isokinetic contractions of the quadriceps at 120 degrees /sec for each leg. Group C subjects trained concentrically only while Group E subjects trained eccentrically only. A t-test for independent means showed no significant right/left differences. ANOVA and Scheffe's F-tests were then used to assess the differences in training effects among the 3 groups for the left leg only. Results showed that although Group C increased slightly in both concentric and eccentric force at all speeds, the gains were significant only for concentric force at 180 degrees /sec. Group E showed significant gains (p < 0.05) in eccentric force at all speeds but not in concentric force. The K group had no significant change in concentric or eccentric force at any speed. We conclude that the eccentric mode of isokinetic exercise has highly specific strength training effects while the concentric mode has less specific training effects. In addition, speed of exercise does not appear to have specific training effects. J Orthop Sports Phys Ther 1989;11(2):70-75.     

Characterization of enterotoxin purified from Clostridium perfringens type C.

Enterotoxin produced by a sporulating culture of Clostridium perfringens type C, which had been isolated from a case of severe necrotic enteritis, was purified. The molecular weight was estimated to be 36,000 by gel chromatography on Sephadex G-100 and 33,400 by ultracentrifugation. The sedimentation coefficient S20,W was 2.92. The toxin protein exhibited unusual behavior on sodium dodecyl sulfate gels, and toxin aggregates having molecular weights of 68,000, 85,000, 105,000, and 140,000 were obtained. The purified enterotoxin often separated, apparently due to slight charge differences, into two protein bands on 7% polyacrylamide gels. Electrofocusing of enterotoxin on polyacrylamide gels gave an approximate isoelectric point of 4.3, with the enterotoxin being fractionated into four distinct protein bands. The specific toxicity of the enterotoxin was about 1,900 mouse mean lethal doses per mg of calculated nitrogen. The data obtained indicate that the enterotoxin from C. perfringens type C is identical in most respects to that obtained from type A strains. Whether or not this toxin plays a role in the necrotic enteritis caused by type C strains is unknown at present.     

Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk

Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer.     

Absorption of histamine from the gastrointestinal tract of dogs in vivo

1. In anaesthetized dogs, various amounts of [(14)C]histamine were introduced into the lumen of a ligated intestinal loop or of the ligated stomach and the absorption of this histamine was studied by determining the radioactive histamine in the venous blood coming from the ligated part.2. After the introduction of 5-5000 mug [(14)C]histamine, into a loop of jejunum, or of 50 mug into a loop of duodenum, ileum or colon, radioactive histamine was detected in all eight successive 15 min samples of venous blood collected during 2 hr. The percentage recovery of the [(14)C]histamine in the blood during this period varied between 0.04 and 3.7.3. After the introduction of 10 mg [(14)C]histamine into the stomach, radioactive histamine was detected in all samples of gastric venous blood collected at various times during the following 4 hr.4. After the introduction of 50-5000 mug [(14)C]histamine into a loop of jejunum, radioactive histamine was also detected in the general arterial blood.5. When a jejunal loop was perfused through its artery with a dextransaline solution, the absorption of [(14)C]histamine from the lumen into the venous effluent was much greater than when the blood supply was kept intact.6. A large part of the [(14)C]histamine introduced into an intestinal loop was inactivated or destroyed either in the lumen or the wall since only a part was recovered in the venous blood, contents and wall of the loop at the end of 2 hr. When different amounts of [(14)C]histamine were introduced into a jejunal loop the recovery was shown to be dependent on the dose. With 5 mug it amounted to about 1% whereas with 5000 mug to 29-42%. The recovery of the [(14)C]histamine introduced into a perfused jejunal loop was greater.7. In dogs and cats large amounts of free histamine were found in the contents of the stomach 2 hr after a meat meal, and much smaller amounts in the contents of loops from the small intestine. The amounts found in the contents of loops from the colon varied greatly.8. In eighteen commercial dog and cat foods the free histamine contents were found to vary over fiftyfold, from 0.06 to 3.5 mg/100 g.9. The significance of the results is discussed in relation to the role of histamine as a humoral agent in the ;gastric' and ;intestinal phases' of gastric secretion.     

Interaction of pre-programmed control and natural stretch reflexes in human landing movements

Pre-programmed mechanisms of motor control are known to influence the gain of artificially evoked stretch reflexes. However, their interaction with stretch reflexes evoked in the context of unimpeded natural movement is not understood. We used a landing movement, for which a stretch reflex is an integral part of the natural action, to test the hypothesis that unpredicted motor events increase stretch reflex gain. The unpredicted event occurred when a false floor, perceived to be solid, collapsed easily on impact, allowing the subjects to descend for a further 85 ms to a solid floor below. Spinal stretch reflexes were measured following solid floor contact. When subjects passed through the false floor en route to the solid floor, the amplitude of the EMG reflex activity was double that found in direct falls. This was not due to differences in joint rotations between these conditions. Descending pathways can modify H- and stretch-reflex gain in man. We therefore manipulated the time between the false and real floor contacts and hence the time available for transmission along these pathways. With 30 ms between floors, the enhancement of the reflex was extinguished, whereas with 50 ms between floors it reappeared. This excluded several mechanisms from being responsible for the doubling of the reflex EMG amplitude. It is argued that the enhanced response is due to the modulation of reflex gain at the spinal level by signals in descending pathways triggered by the false platform. The results suggest the future hypothesis that this trigger could be the absence of afferent signals expected at the time of false floor impact and that salient error signals produced from a comparison of expected and actual sensory events may be used to reset reflex gains.     

Chromosome content and ultrastructure of radiation-induced micronuclei

Unrepaired or misrepaired radiation damage in mammalian chromosomescan result in micronucleus formation at the first cell division.This represents loss of genomic information which may causecell death. To improve our understanding of the mechanism ofradiation-induced micronucleus formation, we characterized micronucleusultrastructure and identified the origin of micronucleus DNA.Immunofluorescence microscopy showed that micronuclei were structurallysimilar to main nuclei since they contained nuclear lamins Aand C and were encapsulated by a network of vimentin intermediatefilaments. The contents of radiation-induced micronuclei werecharacterized using fluorescence in situ hybridization to probefor DNA originating from chromosomes 2, 7, 11 and 16. We postulatedthat if incorporation of DNA into micronuclei were random, thenthe probability of chromosomal DNA in micronuclei would be relatedto the target, i.e. chromosome size. Our results demonstratedthat incorporation of DNA from smaller chromosomes (11 and 16)was not different from expected values but incorporation ofDNA from the larger chromosomes (2 and 7) was significantlygreater than expected. Not all chromosomes in the human genome,therefore, were equally susceptible to genomic loss by micronucleusencapsulation. In conclusion, radiationinduced micronuclei havesimilar structural characteristics to main nuclei, chromosomedamage and/or repair after ionizing radiation may be non-random,and micronucleus formation may reflect this variability. ³To whom correspondence should be addressed