Origins of the high 14-helix propensity of cyclohexyl-rigidified residues in beta-peptides.

[structure: see text] beta-Peptides containing residues derived from trans-2-aminocyclohexanecarboxylic acid (ACHC) display high population of 14-helical secondary structure in aqueous solution. We show that hydrophobic interactions between cyclohexyl rings are not responsible for this conformation-promoting effect, and that polar groups may be attached to the cyclohexyl ring without diminishing the effect.

Antimicrobial 14-helical beta-peptides: potent bilayer disrupting agents.

The interactions of two amphiphilic and cationic, nine-residue beta-peptides with liposomal membranes were studied. These beta-peptides are shown to form 14-helices in the presence of bilayers. Membrane binding and membrane permeabilization occur preferentially in the presence of anionic lipids.

Environment-independent 14-helix formation in short beta-peptides: striking a balance between shape control and functional diversity.

We report a significant and unanticipated advance in the study of beta-amino acid-based foldamers: a small proportion of highly preorganized residues can impart high stability to a specific helical secondary structure in water. Most of the residues in these beta-peptides (2 and 3) are intrinsically flexible. Flexible beta-amino acids can be readily and enantiospecifically prepared in functionally diverse forms, but preorganized residues with side chains are rare and challenging to synthesize.

Structure-activity studies of 14-helical antimicrobial beta-peptides: probing the relationship between conformational stability and antimicrobial potency.

Antimicrobial alpha-helical alpha-peptides are part of the host-defense mechanism of multicellular organisms and could find therapeutic use against bacteria that are resistant to conventional antibiotics. Recent work from Hamuro et al. has shown that oligomers of beta-amino acids ("beta-peptides") that can adopt an amphiphilic helix defined by 14-membered ring hydrogen bonds ("14-helix") are active against Escherichia coli [Hamuro, Y.

Toward beta-peptide tertiary structure: self-association of an amphiphilic 14-helix in aqueous solution.

A major frontier in foldamer research is creation of unnatural oligomers that adopt discrete tertiary structures; at present, only biopolymers are known to fold into such compact conformations. We report an initial step toward helix-bundle tertiary structure in the beta-peptide realm by showing that a 10-residue beta-peptide designed to adopt an amphiphilic helical conformation forms small soluble aggregates in water. Sedimentation equilibrium data indicate that the aggregated state falls in the tetramer-hexamer size range.

[Intraoperative ERCP for therapy of common bile duct stones during laparoscopic cholecystectomy].

The data of 166 patients that underwent laparoscopic cholecystectomy between November 1989 and December 1997 are given. In all cases intraoperative ERC and extraction of bile duct stones within the laparoscopic surgery were performed. The results show that by intraoperative simultaneous ERC bile duct stones can be removed with a success rate of 98.

[Value of intraoperative laparoscopic cholangiography].

Discussion about the necessity of intraoperative cholangiography restarted when laparoscopic cholecystectomy was established. The value of cholangiography was examined in a prospectively randomized study of one hundred patients. We could show that the routinely performed intraoperative cholangiography represents a careful, secure and sensitive method for the detection of common bile duct stones.

[Use of preventive intra-operative antibiotic administration in appendectomy. A pharmacokinetic study].

Studies on Cefazedone-kinetics in serum and subcutaneous fat tissue showed an early and lasting tissue concentration high above minimal inhibitation concentrations so that intraoperative single-shot administration of antibiotics are proven to be effective. Due to these pharmacokinetic patterns the results of an earlier prospective trial is confirmed that single-shot antibiotics during surgery are useful to reduce postoperative wound sepsis rate after appendectomy.

[Proctocolectomy with direct ileoanastomosis and superimposed small intestine pouch].

Our experiences with 26 patients show that total proctocolectomy with direct ileoanal pouch anastomosis and without maintenance of the rectal muscle cuff proves to be an excellent method for secure and lasting treatment of UC and ACR as well as of manifest cancer. The advantage of this method is the maintenance of normal continence function at a lower operative risk and few postoperative complications. Contraindication for this operative approach is still Crohn' disease.

[Pathophysiologic role of the internal anal sphincter in chronic anal fissure].

Internal anal sphincter manometric and myoelectrical investigations were performed under basal conditions and in response to rectal distension in 17 patients with chronic anal fissures and 15 controls. Measurement of sphincter pressures were carried out by pull-through technique, using water perfused open-tip-catheters. Electrical signals were obtained employing concentric needle electrodes inserted into the internal anal sphincter.

[Traumatic duodenal rupture].

Traumatic duodenal perforation has an incidence of 1%-17% (blunt injury) or 1.7%-5% (penetrating injury). Its prognosis correlates to the kind of injury, associated injuries, size of perforation and delayed diagnosis.

[An elastic ileostomy sphincter using an autologous small intestine muscle flap].

To achieve continence in ileostomies by free transplantation of small intestinal smooth muscle according to Schmidt failed frequently because of hemorrhagic necrosis of this graft. To safeguard intact vascularisation of the transplant flapped intestinal smooth muscle was used therefore in 15 dogs with ileostomy for sphincter replacements. Contrary to free grafts, histological studies of flapped small intestinal muscle cuffs show generally undisturbed healing.

[Therapy of intestinal bleeding by the intra-arterial injection of a synthetic vasopressin derivative].

The synthetic drug Ornipressin was injected through a 3-French catheter introduced into the superior or inferior mesenteric artery by a coaxial method in nine patients with massive bleeding from the colon. In all patients the bleeding was stopped. In one female patient with a tumour, bleeding recurred, but was stopped by embolisation treatment.

[Pseudo-obstruction of the colon].

Pseudoobstruction of the colon is characterized by clinical and radiological findings suggesting a mechanical obstruction of the large intestine without any organic cause. 11 of our patients and 344 cases reported in the literature have been reviewed. 90% of the patients have an associated major system disorder, most of them (40%) are localized in the pelvis.

[Pathogenesis of colon diverticular disease (author's transl)].

The longitudinal musculature of the taenia of the colon does play an important role in diverticular disease (DD), as can be found by comparing light and electron microscopic pictures of the colon from healthy persons and patients with diverticulitis and ulcerative colitis. Already in the early stages histological changes can be found, which have to be interpreted as being due to maximal contraction of the longitudinal musculature and to increased metabolism. These morphological changes are accompanied by increased electrical and mechanical activity.

[Diverticular disease; investigation on therapeutical tactics (author's transl)].

In the state of beginning complications if diverticular disease a resection of the inflammed section is indicated. This procedure prevents progression to life threatening complications. However, 5 to 30% of these patients treated in this way will have residual complaints.

[Functional and morphological studies on diverticulosis of the large bowel].

In comparison to the normal colon, longitudinal and circular musculature in diverticular disease (DD) was investigated--regarding motility and morphology--and a comparative measurement between musculature and mucosa was also performed with following results: 1. Only the tenia in DD revealed a spastically contracted muscle. 2.