Absorptive capacity of the transplanted small bowel

Small bowel transplantation (SBT) has been carried out in man in several cases without success, because immunologic problems were unsolved. In experimental SBT a 'two step' model was developed, which enables long term observation of immunologic phenomena. In this model the graft is in a heterotopic position to the recipient's own small bowel. After 35 days the recipient's own bowel is removed and replaced by the graft, now in orthotopic position and again in contact with luminal chymus. To investigate functional and morphological changes, which result from the procedure, the resorption of glucose and water was measured in syngeneic transplanted rats by an in vivo recirculation system and the mucosa was evaluated three dimensionally. The graft mucosa showed a significant reduction in villus height, crypt length and villus surface and a corresponding decrease in glucose and water absorption during heterotopic position. If the graft came into the orthotopic position, the mucosa did regenerate which was expressed by the significant longer crypts of the graft compared with those of the controls, although the graft's villus height and surface are still smaller. Glucose and water absorption increased and were higher in orthotopic transplanted animals, when absorption was expressed per unit intestinal length. The results indicate that in the 'two step' model of SBT the absorption of water and glucose is influenced to such an extent, that recovery is possible after three weeks, thus enabling orthotopic SBT. This almost complete recovery of the mucosa is further evidence of the regeneratory capacity of the small bowel, which enables clinical small bowel transplantation.

Distribution of gastrointestinal hormones in the adaptive response after small bowel transplantation

Enteroendocrine regulatory peptides may play an important role in the adaptation of small bowel mucosa, and it is likely that they act interdependently with neural and luminal stimuli. We assessed their action in rats by morphometric evaluation of enteroendocrine cells after heterotopic accessory small bowel transplantation (SBT), in which the graft is shunted off from the intestinal passage and is entirely deprived of neural connections, and after orthotopic SBT with normal intestinal passage. Sections of the jejunum and the ileum of the graft were immunostained with antibodies to cholecystokinin (CKK), neurotensin (NT) and vasoactive intestinal peptide (VIP). The amount and distribution of positive cells was assessed semiquantitatively. Three weeks after SBT in the heterotopic graft there was a marked decrease in CCK and NT positive cells and VIP positive fibres in the entire organ, compared with the controls. Histological examination revealed that villi and crypts had atrophied. After orthotopic SBT the number of CCK and NT positive cells increased and exceeded normal values by 20-40%. VIP positive fibres did not reach normal amounts. No mucosal atrophy was detected. These findings support the view that the intrinsic neurohormonal system is reestablished in the grafted small bowel and that enteroendocrine regulatory peptides may act as trophic factors that are responsible for adaptation after SBT.

Mapping of activation changes within the acutely ischaemic canine specialised conduction system

Ligation of the anterior septal artery was used to produce acute ischaemia of the specialised conduction system in ten dogs. Activation times at selected positions within the specialised conduction system were recorded. Marked delays of activation occurred between several discrete anatomic sites within the specialised conduction system. This study demonstrates that extremely slow conduction is common in localised areas of the acutely ischaemic infra-nodal conduction system. Heterogeneity of myocardial activation secondary to changes of speed of the conduction during acute septal ischaemia is postulated as a mechanism facilitating the occurrence of malignant ventricular arrhythmias.

Transtelephonic monitoring of a tachycardia-terminating pacemaker

A 66-year-old female with recurrent supraventricular tachycardia which worsened progressively was treated with an implanted tachycardia-terminating pacemaker after treatment with antiarrhythmic drug therapy had failed. The pacemaker had the capacity to detect and respond to tachyarrhythmias. Reliable sensing and termination of the patients tachycardia was accomplished in over 100 inductions of the tachyarrhythmia. Use of this tachycardia-terminating pacer has given us several new insights that may be important in the care and follow-up of all pacemaker patients.

Microbial contamination of enteral feeding solutions in a community hospital

Seven related studies were done to estimate the type and amount of contamination that occurred in nutrient feeding solution when administered according to procedure in a community hospital. The initial study was done in a simulated nonclinical setting with select technicians monitoring for gavage systems delivering a commercially prepared nutrient feeding solution. The solution remained sterile over 48 hr. In the second study, various nurses maintained the enteral feeding simulations unaware of the objective of study. Significant contamination was found, but a decrease occurred when the study was duplicated and the nurses were made aware that contamination was the issue being studied. The subsequent study had all gavage equipment in clinical use in the hospital on a given day cultured for microbial contamination. Significant contamination was present and did not decrease when the study was duplicated following inservice training. Suggestions for standards of care are made.

Acute myopathy associated with gasoline sniffing

Acute myopathy and myoglobinuria with markedly elevated creatine kinase (CK) activity developed in an 18-year-old boy on two occasions after gasoline sniffing. No signs of CNS involvement were seen, and the symptoms receded in a few days. The amount of lead in blood and urine exceeded the reference value for subjects with occupational exposure. The component of gasoline that was responsible for the myopathy remains unknown. Acute myoglobinuria appears to be a rare complication of gasoline sniffing.

A possible role of the specialized conduction system in the conversion of ventricular tachycardia to ventricular fibrillation

Electrode recordings from the right bundle branch, His bundle, and right atrium in a canine preparation enabled us to observe the activation of the ventricular myocardium and the specialized conduction system during the conversion of ventricular tachycardia to ventricular fibrillation. At times when ventricular tachycardia degenerated to ventricular fibrillation, asynchronous activation of the right bundle branch and the ventricular myocardium was frequently noted. Such asynchrony of activation was not seen during the spontaneous conversion of ventricular tachycardia to sinus rhythm. We suggest that this asynchronous activity produces increasing fractionation of ventricular activation fronts, which in turn yields fibrillation.

Structural and functional correlations in the atrophic mucosa of self-emptying blind loops of rat jejunum

Marked atrophy of the mucosa develops in self-emptying blind loops of rat jejunum. The application of microdissection techniques revealed a 74% reduction in the mucosal surface area of the blind loops, 3 weeks after their creation. Kinetic studies of the influx of L-phenylalanine and beta-methyl-D-glucoside into rings of blind loops showed that the Km for both mechanisms was unchanged, but that there was a small reduction in the Vmax for both substrates, when expressed in terms of unit weight of incubated tissue; this attained 31% for phenylalanine and 12% for beta-methyl-glucoside. When the kinetic data were combined with the morphometric results, it could be shown that the Vmax for both substrates, when expressed per unit area of mucosal surface, was more than twice as large in the blind loop epithelium as in normal tissue. Such findings indicate either that the individual cells of the blind loop epithelium possess more transport sites than normal, or that there is a greater proportion of absorptive cells within the blind loop mucosa.

The ultrastructure of the thecal cell of the teleost, Oryzias latipes, during ovulation in vitro

Ultrastructural examination of the follicular envelope of the teleost, Oryzias latipes, during ovulation in vitro showed that the follicle cell layer became increasingly dissociated. Microfilaments, measuring 50-70 A, were sparse in the thecal cells at the start of incubation, but were organized into bands after 5 hr, and into bundles after 10 hr of incubation. It is suggested that these microfilaments are contractile and are involved in cell movement during ovulation.

The effect of a low energy diet on the concentration of DDT in the adipose tissue of turkeys

Turkey hens which had completed a breeding season and contained DDT in their fat were divided into 2 groups of 20 hens each. One group was fed a high wheat control diet throughout a 6 week period while another group was fed a low energy diet for 3 weeks and then the control diet for 3 weeks. Biopsy samples of adipose tissue taken initially and at 3 weeks and carcass adipose tissue samples of 6 weeks were analyzed for DDT and DDE. Total DDT concentration in adipose tissue increased when the hens were fed the low energy diet but decreased again when fed the control diet so that the overall change in DDT concentration over the 6 week period was not different for the two groups. The biopsy technique used in this study was successful in greatly reducing variability and improving precision.