Biomedical subjects

T Groth

Publications and source records attributed to T Groth.

151 records · Page 9Linked to original sources

PubMedDate not supplied

A knowledge-based system for real-time quality control and fault diagnosis of multitest analyzers.

A PC-based real-time quality control (QC) system for multitest analyzers has been developed as a prototype. The system is built with use of a relational database management system (DBMS). Control values from the various analytical channels are stored and administrated with use of the DBMS. The control values collected during various stages of control are filtered through statistical control procedures and the control status of the instrument is continuously presented in color-coded fields indicating the possible presence of critically sized systematic or random analytical errors. The knowledge about rational trouble-shooting of a specific instrument is represented in a network structure and stored in relational tables of the DBMS. An inference engine performs alternating backward and forward reasoning in the network and guides the operator in trouble-shooting.

Artificial Intelligence↗

PubMedDate not supplied

Synthesis of aldehyde building blocks protected as acid labile N-Boc N,O-acetals: toward combinatorial solid phase synthesis of novel peptide isosteres.

The synthesis of (RS)-3'-tert-butoxycarbonyl-perhydro-1', 3'-oxazine-2'-yl acetic acid and the syntheses of the simple and C-2 substituted 3'-tert-butoxycarbonyl-perhydro-1',3'-oxazine-2'(RS)-yl propionic acids from simple starting materials are presented. The simple compounds were prepared from 1,3-propanediol and 1, 4-butanediol, respectively, via a short series of facile steps, in 70% overall yield in both cases. For the syntheses of the C-2 substituted compounds of the longer homologue, (RS)-3'-tert-butoxycarbonyl-perhydro-1',3'-oxazine-2'-yl propionic acid, a malonic ester route was selected, thus allowing easy incorporation of various side chains. The stability of the novel aldehyde protection group, the N-Boc N,O-acetal moiety, under various acidic conditions was investigated, and it was found to cleanly and rapidly yield the aldehyde under strong acidic conditions or, if desired, slower under less harsh conditions. As a demonstration of the use of the building blocks, one building block was coupled to a solid support and, after unmasking of the aldehyde, submitted to three different types of nucleophilic reactions (Pictet-Spengler condensation, reductive amination, Horner-Wadsworth-Emmons olefination) followed by further chemical modification, and the identity of the structures were verified after cleavage from the resin.

Acetals↗

PubMedDate not supplied

N-Terminal peptide aldehydes as electrophiles in combinatorial solid phase synthesis of novel peptide isosteres.

N-Terminal peptide aldehydes were synthesized on a solid support and utilized as electrophiles in nucleophilic reactions in order to furnish novel and diverse peptide isosteres. The aldehyde moiety of the peptide was synthesized by coupling a protected aldehyde building block to the peptide and deprotecting it quantitatively in less than 3 min. It was found that protection of the two succeeding amide nitrogens was necessary in order to avoid reaction between the aldehyde and backbone amides. The N-terminal peptide aldehydes were successfully reacted in the following way: (a) reductive amination with a large variety of amines, leading to N-alkyl-gamma-aminobutyric peptide isosteres positioned centrally in the peptide; (b) reductive amination with amino esters, leading to N-terminal 2,5-diketopiperazine peptides; (c) Horner-Wadsworth-Emmons olefination, leading to unsaturated peptide isosteres positioned centrally in the peptide; and (d) Pictet-Spengler condensations, leading to tetrahydro-beta-carbolines either positioned centrally in a peptide or fused with a diketopiperazine ring in the N-terminus of the peptide.

Aldehydes↗

PubMedDate not supplied

Diffusion of reagents in macrobeads.

A simple and effective method of measuring diffusion rates of various acylating reagents in macro beads (in this work diameters greater than 570 microm) of amino-functionalized resins is presented. The extent of diffusion at various points of time was determined by treating beads with a staining reagent ("chloranil", 2,3,5,6-tetrachloro-1,4-benzoquinone) that colored the regions of the beads that had not yet been permeated by reagent (the central part of the beads). The volume of unstained resin (permeated part) was compared with the volume of the stained part, and diffusion rate constants were calculated. Factors influencing diffusion such as reagent concentration, solvent, temperature, resin type, and mechanical effects were investigated. The results showed that diffusion was promoted by increased temperature, good swelling of the resin, small reagents, and high concentrations but not by sonication or mechanical agitation.

Journal Article↗

PubMedDate not supplied

Extracorporeal shockwave therapy for peyronie disease.

While surgery is the mainstay of therapy for Peyronie disease requiring correction of angulation, interest has grown in the application of extracorporeal shockwave therapy (ESWT) as a minimally invasive approach. This article reviews the current literature reporting the use of ESWT for Peyronie disease.

Adult↗

PubMedDate not supplied

Computer simulation of fluid resuscitation in trauma. First pragmatic validation in thermal injury.

A comprehensive pathophysiologic model has been designed to describe the fluid shifts and hemodynamics in connection with fluid therapy for patients who have had trauma. The model is used to simulate treatment of a patient with burn injury, and these results are compared with measured physiologic and biochemical variables. Various formulas for resuscitation of patients with thermal injuries are also simulated to illustrate the potential use of the "patient simulator" for designing fluid resuscitation programs.

Burns↗

PubMedDate not supplied

A knowledge-based information system for advice in the crisis management of the patient with burns.

A knowledge-based information system that has been designed to be used as an electronic advisor to guide in fluid resuscitation and in the management of the most frequently occurring complications during the first 48 hours after burn injury is described. The system was also developed for training physicians and nurses and may eventually be used for peer review of the management of patients in the burn unit. Ten data screens are used for entry of the administrative data, the clinical background, and the monitored data. The latter include tables for recording fluid therapy and laboratory results. The knowledge base consists of a series of heuristic decision rules that were formulated by a burn care expert and that express the Uppsala fluid resuscitation program to prevent burn shock. The data recorded for a patient are compared with the data in the knowledge base, and the appropriate conclusions are generated. The system's conclusions, the fluid and ventilation prescription, and other required patient management measures are then displayed as a report. The underlying reasoning for each case may be explored by means of the system's explanation facility. The system has been successfully validated by 125 hypothetic cases that represent typical situations of patients with severe burns.

Adult↗