[Three-dimensional 3D modeling: First applications in radioanatomy and interventional radiology under CT guidance]. / Modélisation tridimensionnelle des vertèbres types: Premières applications en radioanatomie et radiologie interventionnelle sous guidage tomodensitométrique.

PURPOSE: To model vertebrae in 3D to improve radioanatomic knowledge of the spine with the vascular and nerve environment and simulate CT-guided interventions. METHOD AND MATERIALS: Vertebra acquisitions were made with multidetector CT. We developed segmentation software and specific viewer software using the Delphi programming environment. RESULTS: This segmentation software makes it possible to model 3D high-resolution segments of vertebrae and their environment from multidetector CT acquisitions. Then the specific viewer software provides multiplanar reconstructions of the CT volume and the possibility to select different 3D objects of interest. DISCUSSION: This software package improves radiologists' radioanatomic knowledge through a new 3D anatomy presentation. Furthermore, the possibility of inserting virtual 3D objects in the volume can simulate CT-guided intervention. CONCLUSION: The first volumetric radioanatomic software has been born. Furthermore, it simulates CT-guided intervention and consequently has the potential to facilitate learning interventions using CT guidance.

[Pain management in bone metastasis of pulmonary origin: new interventional and metabolic techniques]. / Nouvelles techniques interventionnelles et métaboliques dans la prise en charge des métastases osseuses.

Invasion of bone by a metastatic lesion is the most common cause of pain in cancer patients. Pain management in these patients is an important and difficult task. The pain is not always properly controlled by high doses of specific medication, radiation therapy or chemotherapy. When these therapies do not provide adequate pain relief, percutaneous vertebroplasty, cementoplasty, radiofrequency ablation and internal radiotherapy appear to be elegant and efficient complementary alternative pain control methods.

Combined effect of chronic bombesin and secretin or cholecystokinin on the rat pancreas.

This work investigates the pancreatico-trophic action of bombesin, a peptide stimulating pancreatic secretion in vivo and in vitro and examines whether this effect is altered by CCK or secretin. Rats were injected three times daily for 5 days either with saline, bombesin (1 or 10 micrograms/kg), CCK (20 I.D.U./kg), secretin (20 C.U./kg) or a combination of bombesin and CCK or secretin. Bombesin alone induced growth of the pancreas beginning with the dose of 10 micrograms/kg. This growth was characterized by an increase of pancreatic weight, its protein, RNA and enzyme content, but not of its DNA content. The ratios of the three former parameters to DNA increased, suggesting cellular hypertrophy. Cholecystokinin alone exhibited a similar trophic action on the pancreas as bombesin. Secretin alone had no effect on pancreatic size and composition. Cholecystokinin and secretin did not modify the pancreatico-trophic response of bombesin. These findings suggest that bombesin, administered for 5 days in the rat, induces pancreatic growth due to cellular hypertrophy. Cholecystokinin has the same effect. However the mode of action, at the cellular level, of bombesin appears to be different from that of cholecystokinin.

Trophic effect of bombesin on the rat pancreas: is it mediated by the release of gastrin or cholecystokinin?

This work investigates the effect, on the rat pancreas, of a chronic administration of bombesin in function of the dose and duration of treatment and examines whether this effect may be mediated by the release of endogenous gastrin or cholecystokinin. Bombesin, administered three times daily for 5 or 15 days, induced a marked increase in pancreatic weight, its protein, RNA and enzyme contents with the dose of 10 micrograms/kg body weight; the ratios of pancreatic weight, protein and RNA contents to DNA contents increased significantly after a 5 day treatment, suggesting cellular hypertrophy. Pancreatic DNA content was markedly enhanced after a 15 day treatment, suggesting cellular hyperplasia. Antrectomy decreased plasma gastrin levels, but did not alter the pancreatico-trophic action of a 10 micrograms/kg bombesin treatment for 5 days. Proglumide, an inhibitor of cholecystokinin and gastrin in the pancreas, did not affect the growth of the pancreas induced by a 10 micrograms/kg bombesin treatment for 5 days. It is concluded that chronic bombesin induces, in the rat pancreas, cellular hypertrophy or hyperplasia depending on the duration of treatment. Pancreatic hypertrophy is not mediated by the release of endogenous gastrin or cholecystokinin.

Introducing simultaneous spatial resolution and attenuation correction after scatter removal in SPECT imaging.

A new approach to simultaneous spatial resolution and attenuation correction in SPECT imaging is presented. Before these corrections, scatter is removed on the projections. This removal is performed by spectral constrained factor analysis. The innovation reported here is the use of the different impulse responses of the system, according to the source-detector distance, and their integration in a generalized version of the Chang attenuation correction method. This novel algorithm is evaluated on computed and physical phantoms. In the computer-simulated phantom, the count rates after full-processing are very close to the initial values. In the physical phantom, the contrast is increased by 1.8 after full processing. The activity profiles drawn both on raw projections and reconstructed slices demonstrate the effectiveness of the algorithm for the restoration of spatial resolution. Furthermore, the method improves the quality of the images greatly. A clinical study is also presented. When the whole procedure is applied, the resulting slice matches the corresponding computed tomographic scan very well, which is not the case with the usual back-projected images. The process is fully automatic and the computing time performance allows its daily use for single photon emission tomographic examinations.

[Intestinal motility following jejunal resection: electromyography study in the rat]. / Motricité intestinale après résection jéjunale: étude électromyographique chez le rat.

The influences of massive resections on motility of the small intestine remain poorly known. The aim of our study was to determine the effects of jejunal resection on the pattern of occurrence of the migrating myoelectric complex and its postprandial inhibition. The experiments were performed over a period of 1 month after surgery. Transections were done on the jejunum or on the ileum in sham-operated animals. Ten days after resection, the motility of the anastomosed jejunal and ileal segments was dissociated. After one month, a functional continuity appeared through the anastomosis: the whole intestine worked synchronously at the same rhythm as the ileum. Food intake induced an increase in the frequency of the migrating myoelectric complexes measured 10 days after surgery. An adaptative phenomenon appeared after 30 days, the postprandial motor activity returning to its control level.

Gastrin modulation of pancreatic growth.

Gastrin has been proposed as a trophic factor for the pancreas. Extensive small-bowel resection increased transiently plasma gastrin levels in the rat and produced pancreatic growth. This growth was characterized by an increased pancreatic weight, protein and DNA content, and the occurrence of mitotic figures in acinar cells. In order to determine if gastrin is implicated in pancreatic hyperplasia, we induced endogenous variations of gastrin 3 weeks before small-bowel resection or transection. Hypogastrinemia was produced by antrectomy and hypergastrinemia by vagotomy plus pyloroplasty. Pyloroplasty alone was without any effect. All gastric operations alone enhanced though not significantly the weight of the pancreas and its content in protein and DNA. When performed before intestinal resection, they did not modify the hyperplastic response of the pancreas to the resection. Our findings do not support the views that antral gastrin exerts a trophic action on the rat pancreas and that gastrin is implicated in postresectional hyperplasia of the gland.

Rat intestinal brush border enzymes release by deoxycholate in vivo.

The release of proteins, sucrase (SA), maltase (MA), leucine aminopeptidase (LA) and alkaline phosphatase (AP) activity from rat jejunum by sodium deoxycholate (DOC) was studied by an in vivo perfusion technique. In our experimental conditions, a 2 mmol/1 DOC perfusion for 30 min induced a marked and reversible release of proteins and hydrolases. When specific activities were considered, each enzyme showed a distinct release pattern. Significantly, the SA release was largely increased, the AP release was decreased and there was no correlation between the releases of SA and AP. Furthermore, the various enzymes recovered into the lumen were solubilized at different extents. SA was chiefly present in a soluble and AP in a particular form. The microscopical appearances showed a slight exfoliation of the epithelial cells from the villous tips but no specific changes when compared to the control group. The results are discussed in terms of enzymic localization in the brush border membrane; SA would be located very superficially in the surface membrane and AP buried in the membrane and less accessible than the other enzymes.

The relationship between surface tension and release of rat jejunal brush border membrane hydrolases induced by sodium deoxycholate.

Rat jejunum was perfused in vivo with sodium deoxycholate concentrations ranging from 0.125 to 4 mM. The release of total protein and some brush border hydrolases (sucrase, maltase, leucine aminopeptidase and alkaline phosphatase) was followed as a function of both the time and the deoxycholate concentration. 1. Protein and enzyme release increased during deoxycholate perfusion only at concentrations greater than 0.5 mM. For each case, a plateau was reached at 2 mM deoxycholate. 2. After removal of deoxycholate from the perfusion fluid, the rate of protein and enzyme release dropped to the control levels. Following perfusion with 0.125 mM deoxycholate, however, there was a stabilizing effect so that the release rate of sucrase, maltase and alkaline phosphatase (but not of protein and leucine aminopeptidase) was smaller than that of the controls. 3. Protein and enzyme release was correlated with the deoxycholate-induced changes in surface tension. Significant increases in the release rates began between 0.5 and 1 mM deoxycholate when the surface tension fell below 50 dynes/cm. The plateau observed at or above 2 mM deoxycholate coincided with the stabilization of surface tension at 46 dynes/cm. 4. The maximum releasing effect also coincided with the critical micellar concentration of deoxycholate (1.5-2.5 mM).

Do low doses of deoxycholate modify the release of rat jejunal brush border hydrolases?

The in-vivo effects of sodium deoxycholate (DOC) at low concentrations on the release of protein and some brush border hydrolases, sucrase (SA), maltase (MA), leucine aminopeptidase (LA), alkaline phosphatase (AP), have been investigated in the rat by a jejunal perfusion technique. During perfusion with DOC (0.125 or 0.25 mmol/l), enzyme release was not enhanced. After removal of DOC from the perfusion solution with 0.125 mmol/l DOC, there was a steady release of SA, MA and AP although enzyme release was increased linearly in the control and the 0.25 mmol/l DOC groups. The results also confirm the deep localization of AP within the membrane.

Effects of resection on the electrical slow wave in canine jejunum.

The slow wave (SW) was studied in the dog intestine after a 15 cm long jejunal resection, by means of an automatic method which measures each individual SW cycle duration, the SW mean period and its standard deviation during 3 postoperative weeks. Distal to the site of anastomosis, the SW frequency dropped. 3 weeks after the resection, it was partially restored. The standard deviation increased as well caudad as orad to the anastomosis when compared to control dogs. The differences with the controls were even enhanced with time. These results suggest that the intestinal motility is altered at least during 3 weeks after a jejunal resection.

Computer program for intestinal spike bursts recognition.

A FORTRAN program has been developed for locating intestinal spike bursts and for estimating their strength. Tested against human scanning, the reliability rate was 92% and the misrecognition rate was 2.5%. This program was applied to the automatisation of the Migrating Myoelectric Complex analysis. A first method computed the percentage of Basic Electrical Rhythm (BER) cycles with superimposed spike bursts. A second one was based on the evaluation of spike bursts strength.

Effect of sodium deoxycholate on intestinal glucose absorption and (Na+-K+)-atpase in the rat.

The effects of deoxycholate on glucose transport and intestinal (Na+-K+)-ATPase activity have been investigated in the rat jejunum in vivo using a perfusion technique.

Changes in motility after jejunal and ileal resection: electromyographic study in rats.

The aim of this work was to compare the effects of massive jejunal and ileal resections on intestinal motility using an electromyographic technique. Male Wistar rats were used: in the first group a massive jejunal resection was performed, conserving a 7-cm segment after the ligament of Treitz; the rats of the second group underwent an ileal resection, preserving 7 cm of the terminal ileum. Motility was studied at the 10th and 30th postoperative days by means of electrodes implanted throughout the remaining bowel and was expressed by the pattern of recurrence of the migrating myoelectric complex (MMC). In a fasting state, in both transected and resected animals at the 10th postoperative day, the gradient in the duration of MMC along the intestine still existed. However, on the 30th postoperative day, in animals with jejunal resection only, there was an adaptive process: the duration of MMC in the remaining jejunum was significantly increased to the duration in the ileum. After the end of the postprandial inhibition of the appearance of the MMC, on the 10th postoperative day there was a significant decrease in the duration of MMC in the ileum in both types of resection, compared to the controls. However, on the 30th postoperative day, the duration of MMC returned to its control value. In conclusion, jejunal resection seems to induce more important adaptive processes in intestinal motility than does ileal resection. The different results are discussed.

Effect of chronic bombesin on pancreatic size, composition and secretory function in the rat.

Bombesin administered subcutaneously to rats, three times daily for four days, induces pancreatic growth at a dose of 10 micrograms/kg. Growth was characterised by an increased pancreatic weight and content in protein and RNA, accompanied by cellular hypertrophy. Chronic bombesin also enhanced the pancreatic content in chymotrypsin and to a lesser degree its contents in amylase and lipase. The volume of the secretion and the output of enzymes in response to CCK under an infusion of secretin, however, remained unchanged although the functional capacity of individual cells to secret amylase and lipase was reduced. It is concluded that chronic bombesin exerts a trophic action on the rat pancreas but decreases the sensitivity of each cell to hormonal stimulation.

[Perfecting of a technic for the in vivo study of intestinal absorption of monosaccharides in rats]. / Mise au point d'une technique d'étude de l'absorption intestinale des monosaccharides chez le rat, in vivo

A method for in vivo perfusion of isolated jejunal and ileal loops with catheterisation of the efferent veins is described in the rat. The haemodynamical, histological results and the steadiness of D-glucose absorption showed that there functional ability was preserved at least during one hour. D-glucose is absorbed faster by the jejunal than the ileal portion in the rat.

Relationship of electrical slow wave and spike bursts in the dog jejunum in vivo.

The temporal relationship between the slow wave and the spike bursts was studied in the fasted and the fed states in conscious dogs implanted with serosal electrodes on the jejunum. A fully automatic computerized method processed more than 225 h of recording. For each slow wave cycle that contained a spike burst, the program computed the cycle duration and the times elapsed from the beginning of the cycle to the onset and to the end of the burst. In the fasted state as well as after feeding, the spike bursts began and ended at any time within the segment of the slow wave cycle on which spike activity occurred. These results indicate that in vivo in the dog jejunum, the temporal relationship of the slow wave and spike bursts is not fixed. They suggest that the slow wave allows the spikes to occur during limited time intervals, but does not determine their precise location and duration within these intervals. Furthermore, differences existed in the patterns of the slow wave and in its relationship with spike activity (period, location, and duration of the segment on which the spike bursts occurred) between the various phases of the migrating myoelectric complex in the fasted state and the fed state.

Electromyographic characteristics of small bowel motility in the rat.

Rats are widely used in intestinal motility studies, but no precise observation has yet been carried out on the organization of motility throughout the whole small bowel of the rat. The aim of this work was to investigate the characteristics of small intestinal motility of the rat using an electromyographic technique. The variables describing the pattern of occurrence of the migrating myoelectric complex (MMC) were studied as well as the relative distribution of the 3 phases within the MMC cycles. The mean duration of the MMC was 20 min on the jejunum, and it increased up to twofold along the ileum. The propagation of the MMCs was regular in the jejunum, but about half the MMCs disappeared along the ileum and did not reach the caecum. The electromyographic characteristics of the jejunum are greatly different from those of the ileum, and the motility of a segment is not representative of the whole small bowel motility. Considering these particularities of intestinal motility, rats differ in many details from other species.

Intrahepatic lymphoid tissue graft: course of the Gvh reaction induced by Peyer's patches.

To investigate the thymus-dependent immune competence of Peyer's patches, the course of splenomegaly and hepatic perivascular infiltration (PVI) was studied as criteria of graft-versus-host reaction (GvhR). Parental or F1 hybrid lymphoid tissues, were intrahepatically implanted and the ability of Peyer's patches to induce a GvhR was compared to that of spleen, lymph nodes and thymus. A slight but significant delayed increase of spleen index was observed at the 40th post operative day following Peyer's patches implantation whereas the thymus did not induce any modification of this parameter. On the other hand, the PVI was a very early and precise criterion in monitoring the Gvh reaction induced by Peyer's patches, and allowed to postulate that at least one T-cell function is present within the Peyer's patches.