In vivo laser-induced fluorescence imaging of a rat pancreatic cancer with pheophorbide-a

Laser-induced fluorescence (LIF) of pheophorbide-a (Ph-a) was used for imaging of a rat pancreatic tumor. Using a dimensionless function (the ratio of Ph-a fluorescence by bluish autofluorescence), the fluorescence contrasts between excised tumors and their paired pancreas were investigated up to 48 h after a 9 mg kg-1 Ph-a intravenous administration. Among five tested excitation wavelengths, 355 and 610 nm excitations gave the best distinctive contrasts, both 48 h after dye injection. The LIF imaging of six intrapancreatic tumors and six healthy pancreas was carried out in vivo using two laser excitations: 355 nm (Nd:YAG + tripling) for bluish autofluorescence and 610 nm (rhodamine 6G dye) for reddish autofluorescence and dye emission. Images were recorded through bandpass filters at 470 and 640 nm (autofluorescence) and at 680 nm (dye + autofluorescence) with an intensified charged-coupled device camera. Autofluorescence as Ph-a fluorescence images did not allow accurate LIF diagnosis of pancreatic carcinoma. An image processing, including for each pixel a computed division of Ph-a fluorescence (after subtraction of reddish autofluorescence) by bluish autofluorescence intensity generated poorly contrasted tumor images in five of six and false tumor localization in one of three of the tumor-bearing pancreas. A fitting of the digital 640 nm autofluorescence up to the mean 680 nm fluorescence intensity in pancreas prior to subtraction allowed a safe diagnosis to be made with well-contrasted tumor images. To assess automation ability of the processing, a same fitting coefficient (mean of individual values) was applied. In this way, false-negative (one of six) and false-positive (two of six) images were present in tumor-bearing animals as false-positive in one-half of the controls. A successful standardized procedure was then applied with a normalization of 640 and 680 nm pancreas intensities to a same set threshold prior processing. In opposition to thin-layered hollow organs, such as bronchial tube or digestive tract, LIF imaging of carcinoma inserted in a compact organ is exhausting. The use of a dye excitable in the red wavelength range (610 nm for Ph-a) may partly solve this problem, rendering LIF imaging more accurate and potentially automated.

Influence of CO2 pneumoperitoneum on systemic and peritoneal cell-mediated immunity

Port site metastases could be due to mechanical reasons or impairment of host defenses. As it is known that carbon dioxide is toxic for lymphocytes in vitro we decided to investigate lymphocyte stress during laparoscopy. Blood samples and peritoneal fluids were obtained before and after pneumoperitoneum from 16 patients undergoing laparoscopic cholecystectomy. Lymphocyte subsets were determined by flow cytometry. Propidium iodide was used as a lymphocyte vitality test. Cytokines were measured by an ELISA system. Significant falls in the absolute lymphocyte count and T3 and T4 lymphocytes occurred on postoperative day 1 with a quick return to the preoperative value on day 2. T8, natural killer cells, T4/T8, and T4+/T8+ counts were stable. Interleukins 1 beta and 6 and tumor necrosis factor-alpha were depressed during the two postoperative days. Peritoneal lymphocytes were not destroyed by pneumoperitoneum as demonstrated by the propidium test, nor were they locally impaired by carbon dioxide. The circulating lymphocyte subpopulation decrease favors moderate, brief immunodepression. The origin of port site metastases is not immunologic depression but, rather, facilitated implantation of malignant cells by hyperpressure into raw tissues.

Laparoscopy not recommended for routine appendectomy in men: results of a prospective randomized study

BACKGROUND

Laparoscopic appendectomy has now gained wider acceptance in clinical practice, particularly in the treatment of women with right iliac fossa pain. However, the precise role of laparoscopic appendectomy in men is unclear, and this study was therefore undertaken to examine this specific issue in a prospective randomized trial.

METHODS

One hundred men between the ages of 16 and 65 years who had suspected appendicitis were recruited and randomized to undergo either open or laparoscopic appendectomy. Both groups were compared in terms of their clinical parameters, duration of anesthetic and operation times, postoperative pain, duration of ileus, and length of hospital stay.

RESULTS

The histologic confirmation of appendicitis was present in 94% of the cases for both groups of patients. Laparoscopic appendectomy required significantly longer anesthetic time (72.5 minutes versus 55 minutes) and actual operating time (45 minutes versus 25 minutes) compared with open appendectomy. Postoperative pain as measured by visual analog scale on postoperative days 1 and 2 were not significantly different between the patients who underwent laparoscopic and open surgery with values of 4.7 versus 4.4 and 2.1 versus 2.2, respectively. Also no significant difference was seen between the laparoscopic and open appendectomy groups in the recovery of bowel function (24.7 hours versus 21 hours) and in the length of hospital stay (4.9 days versus 5.3 days).

CONCLUSIONS

The results of this prospective randomized trial showed that there were no significant advantages of laparoscopic appendectomy over open appendectomy for the treatment of male patients with suspected appendicitis. We recommend that the use of laparoscopy be limited to men with atypical pain of uncertain diagnosis and in obese patients.

[Celioscopic digestive surgery: from the explosion to a critical reflexion]

A critical review of laparoscopic digestive surgery indications is proposed. Patient's benefit by laparoscopy is to undergo the same procedure as by open surgery with identical security conditions but with less postoperative pain and an earlier recovery. Today laparoscopy in digestive surgery is mainly indicated in the fields of functional and benign diseases. Oncology seems for our team to stay a relative contra-indication as yet. Taken into account the future technical progresses, this 1996 state of the art is obviously only a temporary view of the technique before expected mutations.

Photodynamic imaging of a rat pancreatic cancer with pheophorbide a

Laser-induced fluorescence of pheophorbide a (Ph-a) was used for in vitro photodynamic imaging (PDI) of a rat pancreatic acinar tumor. A 400 nm excitation induced a 470 nm autofluorescence and a 678 nm dye fluorescence in tumors and their surrounding pancreas 24 h after a 9 mg kg-1 body weight Ph-a intravenous administration. With lower intensities in these blood-rich tumors than in pancreas, Ph-a fluorescence signals are unable to provide tumor images. A dimensionless function (the ratio of Ph-a fluorescence by autofluorescence, called Rt for the tumor and Rp for the pancreas) was used for fluorescence contrast calculation (C = Rt/Rp) between six tumors and their paired pancreas. Among five available laser excitation wave-lengths, only the 355 nm excitation gave a distinctive contrast (C = 1.5). The PDI of six intrapancreatic tumors and their intraperitoneal metastasis and of two control normal pancreas was thus performed ex vivo using a 355 nm excitation source delivered by a tripled Nd:YAG laser and a charged-coupled device camera. Fluorescence images were recorded at 680 nm (dye), 640 nm (background) and 470 nm (autofluorescence) through three corresponding 10 nm width bandpass filters. Computed division for each pixel of Ph-a fluorescence values by autofluorescence generated false color image. In this way, contrasted tumor images were obtained. But in five out of six animals false-positive images were present due to an autofluorescence decrease in some normal pancreatic areas. A 470 nm autofluorescence imaging on the same tumors gave in all cases false-positive image and false-negative in half of the cases. These observations suggest that autofluorescence alone is unable to achieve accurate PDI of pancreatic carcinoma and that using Ph-a as a PDI dye needs strong improvements.

Biomaterials for primary closure of a choledochotomy in dogs

Since primary closure of the common bile duct is often not undertaken because of the risks of biliary leakage and peritonitis, we have evaluated feasibility and reliability of closure using biomaterials. In three groups of dogs, an unsutured choledochotomy was closed with circular glued patches: a scleroprotein patch in 4 dogs and an oxidized, compressed human collagen patch reinforced (n = 6) or not (n = 6) with three stitches. The scleroprotein patch (n = 4) was resorbed too soon, and in 2 dogs the unstitched collagen patches became unglued; biliary leakage was the result in both instances. The bile duct healed successfully within 1 month in the other 10 animals fitted with collagen patches, despite one common bile duct stricture. Safe primary closure of a choledochotomy may be envisioned in humans if the duct suture is protected by this new collagen biomaterial.

Experimental pancreatic cancer in the rat treated by photodynamic therapy

Selective histological necrosis of experimental pancreatic carcinoma by photodynamic therapy (PDT) has been successful with haematoporphyrin derivatives and phthalocyanine as photosensitizers. This report describes the feasibility of PDT with pheophorbide A as the photosensitizer to treat azaserine-induced pancreatic rat carcinoma and analyses survival of the animals. An organ distribution study 24 h after pheophorbide A administration (9 mg/kg intravenously) gave a selectivity ratio of 13.5:1 between tumour and surrounding tissue. Light of 660 nm and 100 J/cm2 induced selective necrosis of the tumour. Six of nine rats were cured in 120 days whereas all 36 control animals died within 35 days (P < 0.01). The pancrease and hepatic pedicle were relatively unaffected by PDT, but the duodenum was injured.

[Aphasia caused by isolated lesion of the semi-ovale centre: contribution of the measurement of cerebral blood flow]

Sudden onset stroke occurred in a right-handed vietnamese woman speaking, reading and writing french fluently. When first seen in our department, the patient had mild right facial paresis and non fluent atypical aphasia. CT scan and MRI showed a left subcortical infarct in the superficial territory of the middle cerebral artery; only white matter of the semiovale centre was involved. Neurological examination revealed linguistic impairment resembling transcortical motor aphasia, with unusual stuttering, hypophonia, occasional semantic paraphasias and phonological reading and writing abnormalities. Non verbal cognitive function, gestural and buccofacial praxes were normal. Cerebral blood flow study by SPECT was consistent with left sylvian functional deactivation.

MRI in cerebral venous thrombosis

Fifty-three patients with cerebral venous thrombosis (CVT) were explored by MRI. Three types of signal abnormalities were observed in thrombosed sinuses: 1) isosignal on T1-weighted sequence and low-intensity signal on T2-weighted sequence (early stage); 2) high-intensity signal on T1-and T2-weighted sequences (intermediate stage); 3) isosignal on T1-weighted sequence and high-intensity signal on T2-weighted sequence (late stage). Signal abnormalities in dural sinuses enabling CVT to be diagnosed were absent in 2 out of 53 cases. Twenty-six out of 53 patients had venous infarction. These lesions were haemorrhagic in 20 cases. MRI made it possible to follow the course of CVT in 15 cases, showing partial or complete recanalization of the occluded sinuses in 14 cases. Our study confirmed that MRI is an excellent non-invasive method to explore CVT. It diagnoses the venous thrombosis, studies parenchymal lesions and follows the course of CVT under treatment. However, MRI is less sensitive than arteriography, particularly in cases of CVT involving only the cortical veins.

[Treatment of perforated duodenal ulcer: the celioscopic approach]

Ten patients underwent laparoscopic surgery for typical perforated peptic ulcer symptomatology. Two conversions to open surgery were due to technical problems related to delayed hospital admission. Nine patients underwent duodenal suture reinforced with fibrin glue, and one perforation was only glued. The postoperative course was uneventful without abdominal septic or abdominal wall complications in the eight patients treated by laparoscopy. Laparoscopic surgery may become the method of choice for the treatment of perforated peptic ulcer.

Implication of cholecystokinin in pancreatic adaptation after biliopancreatic bypass in the rat

Biliopancreatic bypass (BPB), a bariatric surgical procedure, leads to a malnutrition-induced general visceral atrophy except for the pancreas. This work investigates the implication of cholecystokinin (CCK) in the exocrine pancreatic adaptive process using a plasma CCK assay and the CCK receptor antagonist CR 1409. No significant reduction in weight and DNA content of the pancreas was noted 36 days after BPB, while a strong decrease in protein, enzymes and RNA contents indicating cellular hypotrophy became apparent. CR 1409 treatment strongly depressed pancreatic weight and its DNA content in BPB animals, suggesting an additional hypoplasia; however, the reduction in pancreatic enzyme content was not aggravated. BPB increased plasma CCK concentrations by 160%, unrelated to CR 1409 treatment. These results indicate that: (1) CCK is involved in the pancreatic adaptive response after BPB in rats, and (2) in the context of a protein malnutrition state, CCK dissociates its pancreatic growth and enzymatic effects, favouring the former.

Trophic and enzymatic adaptation of the intestine to biliopancreatic bypass in the rat

Biliopancreatic bypass (BPB), the exclusion of a duodenojejunal loop from the digestive continuity, has been proposed as a bariatric procedure for treatment of morbid obesity. The present study in rats investigated the effect of this surgical procedure on the mucosae of the ileum directly anastomosed to the stomach, and of the jejunum irrigated only by biliopancreatic secretions. The proximal part of the ileum adapted by two-fold increases in its mucosal mass, total protein and RNA content; DNA content was four-fold higher than in sham-operated animals. There was a correlated increase of mucosal enzyme content, except for lactase. In the distal ileal mucosae, a slight, transient augmentation of mucosal mass, protein, DNA and RNA content was observed which tended to compensate for the shortening of the functional gut. No morphological changes were found in the excluded loop, probably because of an endoluminal stimulation by biliopancreatic secretions. Thus, in BPB, biliopancreatic secretions seem to exert trophic effects on the intestinal mucosa, but they are less potent than the endoluminal nutrition that restores the oral-aboral mucosal gradient.

[Fundoplication by the Nissen-Rosetti technique using celioscopy. 10 cases]

Ten patients presenting with hiatus hernia and gastro-oesophageal reflux underwent laparoscopic Nissen-Rossetti fundoplication. All patients had either medical treatment failure or invalidating reflux. At present, complete fundoplication is the most effective surgical treatment of gastro-oesophageal reflux. The laparoscopic procedure was rigorously identical with the habitually used "open" procedure, the only difference being the abdominal access. No laparotomy was necessary in our patients, and no major complication was observed. The follow-up showed good clinical results. Laparoscopy has been reported to decrease postoperative pain and ventilatory disorders. Morover, this minimally invasive surgical technique enables rapid resumption of social and professional activities.

[Severe complications after cholecystectomy by celioscopy: lessons from yesterday and today]

The case of a series of grave complications after a laparoscopic cholecystectomy is reported: a common bile duct section diagnosed rather late, hemoperitoneum, inappropriate common bile duct reconstruction and late anastomic leakage, stenosis of an hepatico-jejunal anastomosis, haemorrhage through the external biliary drainage and iterating sepsis. The final outcome was good. The stenotic hepatico-jejunal anastomosis was dilated by a Gianturco self-expanding prosthesis percutaneously placed. As an evidence, this alternative treatment is only exceptional, the treatment of choice for postsurgical benign strictures being surgical repair.

[Boerhaave syndrome or spontaneous rupture of the esophagus]

Spontaneous rupture of esophagus is a rare affection resulting from barotrauma to lower esophagus during the effort of vomiting. The diagnosis is suggested by the presence of violent retrosternal pain after a bout of vomiting following the partaking of a copious meal by an alcoholic patient. Prognosis is dependent on the rapidity of treatment, always surgical and completed by long-term antibiotic therapy. Complementary examinations should be limited to a standard chest x ray and esophageal imaging with water-soluble contrast. Recovery is now the rule for patients treated within 24 hours. Mortality is high in patients diagnosed at a late stage, but this could be reduced by improved recognition of the syndrome.

Distribution of pheophorbide A in normal tissues and in an experimental pancreatic cancer in rats

The in vivo administration and distribution of a potent new photosensitizer, pheophorbide A (PH-A), was investigated in rats. The spectral characteristics were determined. This hydrophobic compound was solubilized by an ethanol/phosphate-buffered saline (PBS) mixture (v/v) and sonicated immediately before i.v. administration. Tissue distribution and the affinity of PH-A for an acinar pancreatic tumor were determined in Lewis rats for up to 48 h after a single i.v. administration of 3 mg kg-1 body wt. Methanol-extracted PH-A was quantitatively determined by fluorescence spectrophotometry at 665.6 nm. The PH-A uptake pattern showed that the reticulo-endothelial system is the major target of PH-A, followed by the gut and then the lung and pancreas. PH-A concentrations in skin were very low. The presence of an enterohepatic cycle was suggested by the PH-A biliary output, intestinal uptake and blood concentrations. Tumor PH-A retention was longer than pancreatic retention. The ratio of tumoral to peri-tumoral pancreas PH-A was 6.7:1, 24 h after i.v. administration. With its similar tissue pattern, better absorption spectrum and lower skin toxicity, PH-A could be a more potent photosensitizer than hematoporphyrin derivatives.

Occupational risk to surgeons of unrecognized HIV infection in a low-prevalence area

Data are available on the occupational risk to surgeons of the human immunodeficiency virus (HIV) for areas of high HIV prevalence but not for low-risk areas and particularly for unrecognized HIV infection. The 40-year cumulative occupational risk to surgeons caring for patients with unknown HIV serologies in a low-prevalence area was estimated. From May 1989 to May 1991, 4119 consecutive patients with unknown HIV status, hospitalized in our department, were proposed for testing; 100% complied. Acquired immunodeficiency syndrome (AIDS) patients and known seropositive patients operated on during this period were excluded from the study. The prevalence of unknown HIV infection was 0.07%. Taking into account the rate of parenteral injuries, the rate of contamination after an infected parenteral injury, and the total number of operations performed during a 40-year career, we estimated the cumulative risk of unknown HIV infection in our area to be 1%. This risk must be added to those of caring for known infected patients. In high-risk areas (cumulative risk 10%), a high standard of infection control is required for every surgical procedure, even if it is expensive or of doubtful efficacy. It is unrealistic to apply this standard in a low-risk area. HIV testing with informed consent of the patient is an imperfect guard against infection but has the advantage of alerting the surgeon to the risk of contamination on a case-by-case basis; it also offers the seropositive patient the best possibility for a longer life expectancy.