A prospective randomised study on narrow-band imaging versus conventional colonoscopy for adenoma detection: does narrow-band imaging induce a learning effect?

BACKGROUND AND AIMS: Colonoscopy is an established method of colorectal cancer screening, but has an adenoma miss rate of 10-20%. Detection rates are expected to improve with optimised visualisation methods. This prospective randomised study evaluated narrow-band imaging (NBI), a new technique that may enhance image contrast in colon adenoma detection. METHODS: Eligible patients presenting for diagnostic colonoscopy were randomly assigned to undergo wide-angle colonoscopy using either conventional high-resolution imaging or NBI during instrument withdrawal. The primary outcome parameter was the difference in the adenoma detection rate between the two techniques. RESULTS: A total of 401 patients were included (mean age 59.4 years, 52.6% men). Adenomas were detected more frequently in the NBI group (23%) than in the control group (17%) with a number of 17 colonoscopies needed to find one additional adenoma patient; however, the difference was not statistically significant (p = 0.129). When the two techniques were compared in consecutive subgroups of 100 study patients, adenoma rates in the NBI group remained fairly stable, whereas these rates steadily increased in the control group (8%, 15%, 17%, and 26.5%, respectively). Significant differences in the first 100 cases (26.5% versus 8%; p = 0.02) could not be maintained in the last 100 cases (25.5% versus 26.5%, p = 0.91). CONCLUSIONS: The increased adenoma detection rate means of NBI colonoscopy were statistically not significant. It remains speculative as to whether the increasing adenoma rate in the conventional group may have been caused by a training effect of better polyp recognition on NBI.

Long-term failure of endoscopic suturing in the treatment of gastroesophageal reflux: a prospective follow-up study.

BACKGROUND AND STUDY AIMS: Several endoscopic antireflux therapies have been marketed, but long-term data on their objective and clinical efficacy are sparse. This report presents prospective 1-year follow-up results, including technical, clinical, and functional success rates, for the first of these treatments to be developed, endoscopic gastroplication (EGP). PATIENTS AND METHODS: A total of 43 EGP procedures were carried out in 38 patients with gastroesophageal reflux disease (GERD). Two or three EndoCinch gastroplications were constructed at the level of the gastric cardia in each patient; five patients were treated twice within 6 - 12 months. Each endoscopic suture joined two gastric folds to each other as a double fold, known as a "gastroplication", in order to narrow the esophagogastric junction. Postprocedure data after 2 months and after 1 year were compared with preoperative data, focusing on symptoms, medication requirements, endoscopic findings, and pH-metry results. RESULTS: In contrast to the findings at 2 months (which showed that 72 % of the sutures were present and that there was a reduction in the percentage of time when the esophageal pH was < 4 from 15.4 % to 8.7 %), the results 1 year after EGP were considered to indicate failure of the treatment in all 38 patients because none of them still had all of the initially placed gastroplications in situ (90 % of gastroplications were lost). The percentage of patients who did not require proton pump inhibitor medication decreased from 52 % at 2 months to only 20 % at 1 year and even more patients had evidence of reflux esophagitis at 1 year (56 %) than had initially demonstrated signs of this (41 %). CONCLUSIONS: EGP has some short-term beneficial effects on clinical symptoms and pH-metry. However, mainly due to the loss of the endoscopically placed sutures, these effects were not maintained at the 1-year follow-up. EGP cannot therefore be recommended for routine clinical use. Better endoscopic methods need to be developed, and they should be adequately tested before being marketed.

[Endoscopic therapy of acute and chronic pancreatitis]. / Endoskopische Therapie bei akuter und chronischer Pankreatitis.

Endoscopic therapy is valuable for both acute and chronic pancreatitis. Early endoscopic papillotomy appears, in the case of a severe course of acute biliary pancreatitis, to be advantageous. Endoscopic drainage can be considered in cases of acute fluid retention and necrosis as well as subacute, non-healing pancreatitis or cyst development. By acute chronic pancreatitis with strictures or bile duct stones, papillotomy, dilation and stent insertion can lead to an improvement in pain symptoms. An improvement in endo- or exocrine function, however, is not expected. Studies on the endoscopic therapy of pancreatitis are still very limited, and recommendations can usually only be made based on retrospective case series.

[Verrucous carcinoma of the esophagus - a rare entity]. / Das verruköse Osophaguskarzinom - eine seltene Entität.

Verrucous carcinoma of the esophagus is a very rare entity. It has a high mortality. Treatment is different. 14 cases are reported. With this 15th case we report on a 66-year-old female with a verrucous carcinoma of the esophagus and surgical treatment after 4 times of recurrence and unsuccessful endoscopic resection of the tumor. The patient received transthoracic removal of the distal esophagus and interposition of the stomach. The patient recovered completely and was discharged from hospital after 18 days. Considering this case therapeutic options will be discussed.

Complete bile duct sequestration after liver transplantation, caused by ischemic-type biliary lesions.

Ischemic-type biliary lesions (ITBLs) are the most frequent cause of nonanastomotic biliary strictures in liver grafts, affecting about 2-19 % of patients after liver transplantation. ITBL is characterized by bile duct destruction, subsequent stricture formation, and sequestration. We report here the case of a patient affected by extremely severe ITBL, with sequestration and disintegration of the entire bile duct system, in which it was possible to extract the complete biliary tree endoscopically in a single piece. Histological examination revealed that all cells of the bile duct wall had been destroyed within 3 months after liver transplantation and replaced by connective tissue. Subsequently, biliary stricture formation occurred at the hepatic hilum, as well as the adjacent large bile ducts. It may be hypothesized that cellular rejection of small bile ducts leads to the vanishing bile duct syndrome, whereas cellular rejection of large bile ducts results in ITBL. The strictures were repeatedly dilated by endoscopic means, allowing successful control of stricture formation, as well as maintenance of liver function. At the time of writing, the grafted organ and the patient had survived for more than 3 years in good health. This is the first detailed report on a sequestration of the entire bile duct system caused by ITBL, successfully treated for several years by endoscopic means.

DNA ploidy is a valuable predictor for prognosis of patients with resected renal cell carcinoma.

BACKGROUND: Renal cell carcinomas (RCCs) are heterogeneous and include several distinct entities with a range of biologic and clinical behaviors from relatively favorable to extremely aggressive. The heterogeneity leads to unpredictable outcome and survival. DNA ploidy is a relatively new predictor differentiating diploid from aneuploid tumor cells according to regular or irregular DNA content. The authors evaluated the predictive value of DNA ploidy in patients who underwent resection because of RCC. METHODS: In a prospective study, 180 patients who underwent resection because of RCC were investigated. DNA cytometry was conducted on each resected tumor to determine DNA ploidy. Patients were completely followed up until death or up to 12 years. RESULTS: Survival analysis showed that patients who underwent resection because of RCC in tumor classifications pT1, pT2, and pT3 survived 10 years in 85%, 53%, and 8% of cases, respectively. Patients suffering from small tumors (pT1 and pT2, n = 44) with diploid nuclei survived 10 years in 94% but only in 8% if the tumor was aneuploid (n = 55). In addition, 91% of patients who underwent resection of large tumors (pT3, n = 12) with diploid nuclei survived 10 years, but no patient with large and aneuploid tumor (n = 51) survived more than 3 years. Furthermore, 92% of all patients afflicted from diploid RCC survived 10 years. This finding was independent of tumor stage. CONCLUSIONS: The results of this study suggest that DNA ploidy is a significant and independent predictor for survival of patients afflicted from RCC and superior to tumor classification and grade. DNA ploidy is a reliable prognostic factor for RCC and yields considerable information for patient management and predicting clinical outcome.

Magnetic resonance cholangiopancreatography-guided unilateral endoscopic stent placement for Klatskin tumors.

BACKGROUND: Advanced and incurable Klatskin tumors of Bismuth-type III and IV cause obstructive jaundice. Palliation of patients with Klatskin tumors is usually carried out by bilateral endoscopic stent placement. Endoscopic retrograde cholangiography (ERC) in such patients is associated with a comparatively high morbidity and mortality mainly due to postprocedure bacterial cholangitis. To reduce ERC-related complications the outcome of replacing ERC with magnetic resonance cholangiopancreatography (MRCP) was investigated. Subsequently, unilateral contrast injection and stent placement were performed, thus avoiding bilateral contrast injection and stent insertion. METHODS: Patients thought to have a Klatskin tumor underwent clinical evaluation, laboratory, and noninvasive imaging studies before ERC. Patients were enrolled in this feasibility study if investigators agreed with the clinical diagnosis of an advanced and incurable Klatskin tumor. MRCP images were used to determine the predominate ductal drainage for the liver segments thus directing stent placement. Based on these findings, unilateral ERC and subsequent unilateral stent placement were performed. Antibiotics were not given before ERC. Amsterdam-type stents (10F) were placed and replaced routinely at 2 months. In cases of earlier occlusion, the stents were replaced immediately. RESULTS: Thirty-five patients underwent MRCP, ERC, and unilateral stent deployment. Two further patients enrolled after MRCP were withdrawn because ERC could not be carried out. In 35 patients with unilateral stents bilirubin levels decreased (18.9 +/- 6.3 mg/dL to 3.2 +/- 2.3 mg/dL) and jaundice resolved in 86%. After first stent deployment, post-ERC bacterial cholangitis occurred in 6% (2 of 35) of patients. CONCLUSIONS: This new method of MRCP-guided endoscopic unilateral stent placement could reduce ERC-related complications caused by initial stent deployment. The results of this study justify a randomized prospective comparative trial.

[Endoscopic therapy of ischemia-type biliary lesions in patients following orthotopic liver transplantation]. / Endoskopische Therapie ischämietypischer biliärer Läsionen (ITBL) bei Patienten nach orthotoper Lebertransplantation.

Ischemic-type biliary lesions (ITBL) mainly induce stenoses in liver transplants causing cholestasis thus endangering the allograft. ERC enables distinction of ITBL from other differential diagnosis. From 1988 to 1998, 1,026 liver transplantations had been carried out at our clinic. 2.4% (25 out of 1,026) of liver transplanted patients were afflicted from ITBL. 60% (15 out of 25) of patients were endoscopically treated by means of sphincterotomy and balloon dilation. Furthermore, some patients needed extraction of calculi (n = 3), bile duct sequester (n = 6) or stenting (n = 4), respectively. Three patients suffered from ITBL type 1 (= only extrahepatic lesions) and five other patients were afflicted from ITBL type 2 (= circumscript intrahepatic lesions). 90% of those patients revealed long-term benefit from endoscopic therapy (follow-up to seven years). Another 15 patients elicited ITBL type 3 (= multiple intra- and extrahepatic lesions). Therefrom, nine patients had to be retransplanted directly while eight others were assigned to endoscopic treatment. Follow-up investigations revealed that retransplantation could be avoided in 50% of ITBL patients by means of endoscopic therapy for at least three years. In contrast, only 27% of ITBL patients could survive for more than three years without endoscopic therapy. Endoscopic success depends on localization and severity of ITBL complications in the biliary tract of the liver allograft. Therefore, benefit of endoscopic therapy depends on proper diagnosis as early as possible guiding further therapeutic strategy. Conclusively, endoscopic success enables maintenance of liver function in ITBL afflicted liver grafts and avoids or at least, delays retransplantation.

Clinical significance of magnetic resonance cholangiopancreatography (MRCP) compared to endoscopic retrograde cholangiopancreatography (ERCP).

BACKGROUND AND STUDY AIMS: The clinical importance of magnetic resonance cholangiopancreatography (MRCP) as a noninvasive diagnostic modality for investigation of the biliary tree and pancreatic duct system is under debate. Using endoscopic retrograde cholangiopancreatography (ERCP) as the gold standard, this study determined in a prospective, blinded fashion the sensitivity and further statistic values of MRCP findings for evaluation of the biliary and pancreatic tract. PATIENTS AND METHODS: Seventy-eight patients referred for ERCP were studied prospectively with MRCP and ERCP during a 12-month period. All images were interpreted on a blinded basis by two radiologists. Any dilations, strictures, and intraductal abnormalities were recorded and correlated with the clinical diagnoses. RESULTS: MRCP images of diagnostic quality were obtained in 76 of the 78 patients (97%). Magnetic resonance cholangiography (MRC) showed sensitivities (and positive predictive values) of 71% (62%) for recognition of normal bile ducts, 83% (91%) for recognition of dilation, 85% (100%) for recognition of strictures, 77% (91%) for correct stricture location, and 80% (100%) for diagnosing bile duct calculi. In addition, the sensitivity of MRC in classifying benign and malignant strictures was 50% and 80%, respectively. The statistical values (sensitivity and positive predictive value) for magnetic resonance pancreatography findings were determined for the recognition of normal pancreatic ducts (33% and 50%), recognition of dilation (62% and 100%), recognition of strictures (76% and 87%) and correct location (66% and 100%), diagnosis of benign strictures (87% and 87%) and malignant strictures (60% and 75%), and for diagnosing pancreatic duct stones (60% and 100%). CONCLUSIONS: MRCP is capable of providing diagnostic information equivalent to ERCP in many patients, and should be applied whenever established techniques provide no results, or inadequate results.

Endoscopic access to the papilla of Vater for endoscopic retrograde cholangiopancreatography in patients with billroth II or Roux-en-Y gastrojejunostomy.

BACKGROUND AND STUDY AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) is an established modality for the diagnosis and treatment of pancreaticobiliary disorders. In contrast to ERCP in patients who have not undergone gastrectomy, ERCP in patients with a Billroth II gastrojejunostomy or a Roux-en-Y anastomosis is considerably more difficult. It was nevertheless considered that ERCP might be possible in most patients with gastrectomies, and this hypothesis was tested. PATIENTS AND METHODS: A total of 2256 patients were admitted to our hospital for ERCP from 1990 to 1994. Of these, 65 (3%) had gastrojejunostomies, either with Billroth II reconstructions or with the Roux-en-Y procedure. ERCP was always performed with a conventional side-viewing endoscope. RESULTS: We examined the 65 patients with gastrojejunostomies. Of these, 91% had Billroth II anastomoses and 9% had received Roux-en-Y reconstructions. We successfully reached the papilla of Vater with the endoscope in 92% of the patients with Billroth II gastrojejunostomies (54 of 59), but in only 33% of the patients with Roux-en-Y reconstructions (two of six). In 8% of the cases of Billroth II anastomosis, it was not possible to advance the endoscope into the duodenal stump, due to intestinal stenoses (5%) or excessive intestinal length (3%). Failure in case of regular Billroth II anatomy occurred only in patients who had not received Braun enteroenterostomies. Failure also occurred in 67% of the Roux-en-Y gastrojejunostomy cases due to excessive intestinal length. CONCLUSIONS: Most patients with Billroth II gastrojejunostomy (92% of those in the present study) and some patients with Roux-en-Y anastomosis (33% of those in the present study) can be investigated by ERCP and endoscopically treated in cases of pancreaticobiliary disorder. Braun enteroenterostomy has no negative impact on the endoscopic access to the papilla of Vater in patients with Billroth II gastrojejunostomy. Surgical reconstruction of the gastrointestinal tract to perform gastrojejunostomy should also take endoscopic requirements into account. In view of both the potential postoperative complications and endoscopic requirements, the jejunojejunostomy should be placed nearer to the gastrojejunostomy than 60 cm, and the afferent loop should be as short as possible.

Endoscopic sphincterotomy using an S-shaped sphincterotome in patients with a Billroth II or Roux-en-Y gastrojejunostomy.

BACKGROUND AND STUDY AIMS: Some patients admitted for endoscopy present a gastrojejunostomy with a Billroth II anastomosis or Roux-en-Y reconstruction. The gastrointestinal reconstruction hampers endoscopic diagnosis and treatment of the biliary and pancreatic tract. The present paper describes a new procedure facilitating endoscopic retrograde cholangiopancreatography (ERCP) in patients who have undergone gastrojejunostomy. PATIENTS AND METHODS: ERCP was attempted in 65 patients with gastrojejunostomy. A conventional side-viewing endoscope was advanced into the duodenal stump, and a modified catheter was pushed through the endoscope. The cutting wire of the modified catheter winds round the catheter at a pivotal point between the catheter's proximal and distal holes. This allows the catheter tip to be forced into an S-shape when the wire is pulled. Since the cutting wire can easily be adjusted to the papillary roof, safe and successful endoscopic sphincterotomy can be carried out. RESULTS: We were able to advance the conventional side-viewing endoscope into the duodenal stump in 92% of the patients (n = 59) with Billroth II gastrojejunostomies, and in 33% of the patients (n = 6) with Roux-en-Y anastomoses. Whenever it was possible to reach the duodenal stump, cannulation and sphincterotomy of the papilla of Vater was successful. Ninety-six percent of the patients who underwent sphincterotomy (n = 54) immediately benefited from biliary decompression. One major complication occurred, with a patient suffering a retroperitoneal perforation during endoscopic sphincterotomy; the patient later died, despite three subsequent surgical operations. CONCLUSIONS: In spite of previous gastrojejunostomy, most patients with Billroth II anastomoses (92%) and many patients with Roux-en-Y reconstructions (33%) can be treated endoscopically for biliary diseases. The use of a conventional side-viewing endoscope in conjunction with an S-shaped sphincterotome can be recommended. This allows safe and successful endoscopic treatment of all patients in whom endoscopic access to the papilla of Vater is possible.

Endoscopic management of biliary complications after orthotopic liver transplantation.

BACKGROUND/AIMS: Biliary complications after orthotopic liver transplantation are still a severe problem and often require a second surgical operation. MATERIAL AND METHODS: In our center we studied 500 patients after liver transplantation. RESULTS: In this patient population, we found 44 patients suffering from diseases of the bile duct system after liver transplantation. Biliary complications were caused by stenoses which were localized most often in the common bile duct of the recipient (65%) but also in the common bile duct of the donor liver (26%) as well as in the anastomosis of common bile duct (9%). In all cases ERC was able to identify location, entity and dimension of the biliary complication thus leading to therapeutic strategy. 66% (27 out of 41) of the patients with biliary complication could be cured definitely by endoscopic methods alone while 29% (12 out of 41) of these patients needed surgical operation and 5% (2 out of 41) received both, endoscopic and surgical therapy. Patients suffering from multiple complications could be cured partially by endoscopic methods improving patient condition for subsequent surgery. Ischemic type biliary lesions of the extrahepatic ducts (ITBL type I) as well as of the intrahepatic ducts (ITBL type II) could be successfully treated by endoscopy. Only rare cases of multiple lesions intra- and extrahepatically due to ITBL type III gave no chance to endoscopy and demanded directly surgical operation. CONCLUSIONS: Our results show that most of the biliary complications after liver transplantation can be resolved by endoscopic treatment.

Management of traction wire fracture complicating mechanical basket lithotripsy.

BACKGROUND AND STUDY AIMS: The application of basket catheters has become the main method of removing calculi from the biliary and pancreatic duct. However, larger or impacted stones have to be crushed and fragmented by mechanical lithotriptors before removal is possible. Sometimes, fracture of the traction wire occurs as a severe and fraught complication. We describe a precautionary measure which helps to manage this complication. PATIENTS AND METHODS: In a series of 569 consecutive patients suffering from bile or pancreatic duct stones we found 60 (10.5%) who required mechanical lithotripsy for oversized or impacted calculi. Mechanical lithotripsy was always performed initially with a long metal sheath (80 cm) in combination with a standard traction wire. If the traction wire fractured we replaced the long metal sheath stepwise by shorter ones (70cm, 60cm and 50 cm, respectively), allowing immediate continuation of the lithotriptic procedure using the same traction wire. RESULTS: During the lithotriptic procedure three of our patients (5%) were afflicted by traction wire fracture. Two patients could be relieved directly by changing the initial metal sheath to shorter ones. Because of the exceptional hardness of a pancreatic duct stone the third patient needed stone fragmentation by extracorporeal shock wave lithrotripsy (ESWL) before complete mechanical clearance of the duct could be accomplished. CONCLUSION: We advocate the initial use of a long metal sheath (80cm) to perform mechanical lithotripsy. In case of traction wire fracture the use of a shorter metal sheath allows immediate successful continuation of the procedure, thereby frequently avoiding procedures such as ESWL or surgery.

Expression of the erb B oncogene in the Morris hepatoma 7777.

Altered expression of protooncogenes/oncogenes is believed to be involved in hepatocarcinogenesis of the chemically induced, transplantable Morris hepatoma 7777. We compared the mRNA expression of c-N-ras and v-erb B mRNA of normal rat liver with that of Morris hepatoma 7777 using Northern blot analysis and in situ hybridization. Northern blot analysis revealed a strong overexpression of the v-erb B related mRNA, while the c-N-ras mRNA was only slightly increased. In situ hybridization using a c-N-ras mRNA probe also showed only a slightly increased number of silver grains in the hepatoma cells compared with normal rat liver. On the other hand, the v-erb B related mRNA was strongly overexpressed in the hepatoma cells, while the connective-tissue capsule, the blood vessels, blood cells and the necrotic foci did not show an elevated v-erb B related gene mRNA expression. Similar results were obtained in liver metastases. The detectable v-erb B hybridization signal was lost by pretreatment with RNase A. We conclude that the c-N-ras gene is of minor importance in the chemically induced, transplantable Morris hepatoma 7777, while the increased expression of the v-erb B related mRNA is due to a selection of ligand-independent tyrosine kinase activity.

Integrins in ageing cartilage tissue in vitro.

Matrix-cell interactions are of great importance for numerous cell functions whereby integrins play an essential role as transmitters of extracellular signals. In cultures of ageing cartilage tissue (organoid or high density cultures) cartilage cells occur on the surface of which thick fibrils of collagen type I are deposited. Since integrins, in their role as receptors, cause an interaction between matrix components and cell membrane, we tried to demonstrate immunomorphologically (light and electron microscopically) the corresponding integrin receptors for collagen type I (beta 1 alpha 1 and beta 1 alpha 2) on the surface of these ageing cartilage cells. Cultures of normal, i.e. young cartilage tissue exhibit only beta 1 alpha 3- and beta 1 alpha 5-receptors; labelling against the integrins beta 1 alpha 1 and beta 1 alpha 2 is not possible in this case. Our results show that after the occurrence of thick fibrils cartilage cells express new receptors (beta 1 alpha 1 and beta 1 alpha 2) on the cell membrane. Thus, in ageing or dedifferentiating cartilage tissue it is not only the synthesis programme of matrix components (e.g. instead of collagen type II >> collagen type I) which changes but also the integrins (instead of alpha 3/beta 1, alpha 5/beta 1 >> alpha 1/beta 1, alpha 2/beta 1) so that new collagen types can be bound. These findings may also serve for a better understanding and interpretation of cartilage changes in vivo during ageing and under pathological conditions.

Expression of vasopressin receptors (V2-subtype) on LLC-PK1 cells during cell culture.

Vasopressin receptor expression on LLC-PK1-cells (a porcine renal tubular cell line) during cell culture is still not fully understood. We studied receptor expression using a novel vasopressin analogue with high specific radioactivity ([125I][8-p-hydroxy-phenylpropionyl]-lys8-vasopressin, 74EBq/mol (2000 Ci/mmol)). LLC-PK1 cells were grown in monolayers for 1 to 6 days. Scatchard analysis performed with membranes of LLC-PK1 cells revealed a single binding site with a binding constant (Kd) of 0.46 +/- 0.04 nmol/l. During cell culture, the binding constant (Kd) was not altered, but receptor density increased significantly (21,115 +/- 645 receptors per cell, day 2; 42,315 +/- 1512 receptors per cell, day 6). A receptor occupancy of about 30% was found to be associated with a cAMP stimulation of 50%. The receptor reserve might be even higher because, by using a highly specific oxytocin antagonist, we found that 20% of the occupied [125I][8-p-hydroxy-phenylpropionyl]-lys8-vasopressin-binding sites are oxytocin receptors. For lys8-vasopressin receptor studies, great care has to be taken to examine cells in identical culture phases.

Delayed type hypersensitivity (DTH): studies on necrotising DTH-reactions against listerial antigen in the skin of guinea pigs.

Delayed type hypersensitivity (DTH) to facultative intracellular bacteria which leads to destructive skin reactions was so far only investigated against mycobacterial antigens in guinea pigs whereas this work investigates destructive DTH-reactions in the skin of guinea pigs which are directed against listerial antigens. Toxic factors of viable listerias induced an enhancement of destructive skin reactions in non-immunised guinea pigs as compared to immunised ones. In contrast, heat killed listerias (HKL) induced necrotising skin reactions in immunised and non-immunised guinea pigs which were significantly enhanced by DTH in immunised guinea pigs. 5 days after immunisation, necrotising reactivity was maximal and increased in a dose-dependent mode with higher amounts of HKL. Listeria-specific T-cells were able to interact specifically with allogeneic macrophages in vitro. By means of adoptive transfer of listeria-specific T-cells it was possible to transfer successfully Listeria-specific DTH-reactivity from immunised donors to non-immunised recipients.

Delayed type hypersensitivity (DTH): quantitative studies of mycobacteria-induced destructive and non-destructive DTH-reactions in the skin of guinea pigs.

Research on delayed type hypersensitivity (DTH) to facultative intracellular bacteria in guinea pigs focused especially on intracutaneous DTH reactions. However, phenomena of erythematous and necrotic skin reactions were only evaluated qualitatively, dose-response relationships not investigated, differences between early and late reactions overlooked and the development of unspecific skin necrosis ignored. In this work, these aspects were investigated by characterisation of DTH-mediated reactions against mycobacterial antigens in the skin of guinea pigs. Intracutaneous injection of mycobacterial antigen into the skin of immunised and non-immunised guinea pigs induced an erythematous reaction which reached its peak after 24 h. On days two and three after challenge, the centre of the erythema blanched and necrotised. During the next days, skin necrosis increased and reached a peak on days six and seven. In immunised guinea pigs, DTH led to a specific enhancement of erythematous and necrotising skin reactions which also appeared in non-immunised guinea pigs. Thus, an early erythematous and a late necrotising DTH-reaction were identified by their morphology and time course. Both types of DTH-mediated allergy revealed dose-dependency from the intracutaneously injected antigen doses. Erythematous and necrotising DTH reactions against viable and killed mycobacteria showed a similar time course and morphology. DTH reactivity which was induced by immunisation with Mycobacterium tuberculosis showed cross-reactivity with antigens of Mycobacterium bovis.

Carrier membrane as a stationary phase for affinity chromatography and kinetic studies of membrane-bound enzymes.

The use of membrane supports as stationary phase, coupled with ligands of choice, allows all kinds of chromatography [Dj. Josic, K. Zeilinger, Y. Lim, M. Raps, W. Hofmann and W. Reutter, J. Chromatogr., 484 (1989) 327] and offers a powerful alternative to both soft gel chromatography and high-performance liquid chromatography. In this work we present affinity membrane chromatography for purification of the enzyme carbonic anhydrase from haemolysates of human erythrocytes. Furthermore, the coupling of the enzymes to the membrane support allows kinetic investigations. As an example, kinetic experiments were carried out by means of carbonic anhydrase coupled to the membrane support using 4-nitrophenyl acetate and 2-chloro-4-nitrophenyl acetate as substrates.

Purification of carbonic anhydrase isoenzymes by high-performance affinity chromatography and hydrophobic interaction chromatography.

Isoenzymes of carbonic anhydrase were purified by a combination of affinity chromatography and hydrophobic interaction chromatography. Immobilization of sulfonamides on an epoxy-activated support provided a stationary phase for affinity chromatography which was stable to hydrolysis by carbonic anhydrase. A first purification step allowed the isolation of enzymes directly from homogenates of human erythrocytes and rat stomach. Without any further preparation, except the addition of ammonium sulfate to the eluate from affinity chromatography, the isoenzymes could be separated by hydrophobic interaction chromatography with very high recovery of protein and retention of enzymatic activity.