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Biomedical subjects

K Ludwig

Publications and source records attributed to K Ludwig.

At least 145 records · Page 8Linked to original sources
PubMed1991

High incidence of serum antibodies to Escherichia coli O157 lipopolysaccharide in children with hemolytic-uremic syndrome.

Because the classic hemolytic-uremic syndrome has been etiologically linked to intestinal infections by Escherichia coli O157 and other verotoxin-producing E. coli (VTEC), we examined 22 consecutive children with acute hemolytic-uremic syndrome for the presence of VTEC, using microbiologic methods, and for a specific immune response to O157 lipopolysaccharide in acute-phase and follow-up sera, using the indirect hemagglutination assay and the immunoblot procedure. Of 22 children with enteropathic hemolytic-uremic syndrome, 15 (68%) had evidence of VTEC infection by culture of the pathogen or detection of free verotoxin in the feces, or both. Significantly elevated titers of short-lived agglutinins and IgM class antibodies against the O157 lipopolysaccharide were found in 20 (91%) of 22 patients, but not in two of three patients with non-O157 E. coli isolates or in healthy children or children with diarrhea caused by other enteric pathogens (p less than 0.01). The combined microbiologic and serologic procedures provided evidence for VTEC infection in all 22 patients. The high incidence of anti-O157 lipopolysaccharide antibodies in these patients indicates the predominance and the pathogenic potential of this serogroup. Both serologic techniques proved to be valuable tools to further characterize this form of hemolytic-uremic syndrome. Future studies on the induction of protective immunity seem warranted.

Antibodies, Anti-Idiotypic↗
PubMed1991

[Consequences of different ablation rates in Bowman's membrane and corneal stroma for photorefractive keratectomy].

If photorefractive keratectomy (PRK) is performed with an ArF-excimer-laser, the existence of different ablation rates in Bowman's membrane and corneal stroma is of crucial importance, as ablation rates are considered to be constant in PRK. Consequently, if photoablation cannot be confined to Bowman's layer alone, at least two new surfaces with different refractive powers would result. For the correction of myopia with PRK, different ablation rates would mean that: (1) the central corneal surface with the desired refractive power is smaller than the total ablation zone. The lower the ablation rate in Bowman's layer compared to that of stroma, the smaller the area of desired refraction. (2) the maximum attainable refractive change will also be smaller, the lower ablation rate in Bowman's layer is compared to that of stroma. (3) Enlargement of the central zone of desired refraction is limited by the maximum acceptable ablation depth.

Cornea↗
PubMed1991

[Changes in the visual field in diabetic retinopathy after grid laser coagulation of the posterior pole of the eye].

The influence of grid laser photocoagulation on the central visual field of 15 eyes with diffuse diabetic maculopathy was studied in a prospective clinical trial. Throughout the 3 month follow-up period, visual fields were monitored by static perimetry using a combination of 30-1 and 30-2 programs of the Humphrey Field Analyzer. Statistical analysis of all clinical parameters shows that visual acuity correlates very well with foveal light difference sensitivity. The overall sensitivity of the 30 degrees field, however, does not correlate significantly with either of them. During the follow-up period, patients' subjective vision improved significantly (p = 0.0234); for the overall sensitivity of the 30 degrees visual field there was a trend towards improvement (p = 0.0692). The sensitivities of the central 10 degrees and 3 degrees of the visual fields, of the fovea and visual acuity did not change. The results of the present study suggest that during the first 3 months after grid photocoagulation of diffuse diabetic macular edema, the treatment affects mainly the retina outside the macula. The improvement in patient vision may be due to these changes in the visual field.

Aged↗
PubMed1991

[Study of the suitability casting patterns for secondary crowns].

A new method of sculpting casting patterns for secondary conical or parallel telescopic crowns was tested in a comparative study. After deep drawing of a carrier foil together with a spacer foil the space maintainer was removed out of the carrier cap. The space between the cap and the primary crown was filled with a light-curing resin liquid. After plymerisation the occlusal gap between this cap and the primary crown was measured in comparison to deep drawn Adapta carrier foils. The result is that the new method gives most accurate casting patterns.

Crowns↗
PubMed1990

Addition of clonidine enhances postoperative analgesia from epidural morphine: a double-blind study.

This study was undertaken to evaluate the analgesic effect of the combination of epidural morphine and clonidine versus epidural morphine alone in patients with postoperative pain. A randomized double-blind design was used, and 91 patients scheduled for post-operative pain relief by epidural morphine were studied. Patients received either a continuous epidural infusion of morphine and clonidine (group 1; n = 45) or morphine alone (group 2; n = 46) over the 72 h after major abdominal surgery. In the first 24 h, the dose of morphine was 6 mg per 24 h; during the second 24 h, it was decreased to 4 mg per 24 h; and in the final 24 h, it was decreased to 2 mg per 24 h in both groups. Group 1 patients received clonidine (450 micrograms) during each 24-h period. Additional epidural bolus injections of 2 mg morphine and intravenous meperidine were given on demand. The pain score, blood pressure, heart rate, respiratory rate, and relative forced vital capacity were measured at fixed times during the first 72 h after operation. Total consumption of analgesics and side effects were recorded. Although the total consumption of analgesics was significantly higher in group 2 (P less than 0.05), pain scores were lower in group 1 than group 2 during the entire observation period (P less than 0.05). Epidural clonidine produced a significant decrease (P less than 0.05) in heart rate and blood pressure, whereas the respiratory rate was not affected. Due to the better pain relief in group 1, the forced vital capacity was increased (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Hot air coagulator for the treatment of bleeding of parenchymal organs].

Experiences are described about the hemostasis in parenchymatous organs by means of a self-constructed hot air coagulator. Bleedings in liver, spleen, and kidney were caused experimentally in 15 dogs. A certain control of hemorrhage were carried out by hot air. The own hot air coagulator was superior to other coagulators by the little weight and the fast and noiseless working.

Air↗
PubMed1989

[Breaking susceptibility of Ultralite-foil crowns for molars].

Proceeding on the assumption that the use of massive cast gold constructions is an important factor in the question of economical dentistry a new technique of crownwork construction is presented. Ultralight construction is a method used in engineering for the production of load-bearing elements from embossed metal foils. Based on the new Ultralite-foil-crown the mechanical strength of the Ultralite-molar-crown is tested. Following the principles in construction with this new technique the results of breaking load tests of the ceramometallic Ultralite-molar-crown are discussed.

Crowns↗
PubMed1989

[Homogeneity and corrosion resistance of cast dental precious metal alloys compared with uncast alloys].

60 cast crowns were manufactured in 6 different dental laboratories using 3 different alloys. The relative areas of cavities at the crown margins and the palatal crown surfaces were measured. Subsequently the crowns and uncast alloy plates were stored in artificial saliva and 1nHCl. After 30 days the dissolved amounts of Cu or, respectively, Ag were measured. All crowns exhibited cavities and porosities. The area of cavities at the crown margins was twice as high as that at the palatal surfaces. The copper ion concentrations measured for cast crowns of the PdCuGaIn-type Pd base alloy were increased by a factor of 20 (maximum) when compared to the uncast alloy. The solubility of the cast PdAgSnIn alloys was characterized by an only slight increase in the amount of dissolved silver. The results suggest that, in view of the inadequacies of dental casting, the use of alloys that may release toxic metal ions should be abandoned.

Copper↗
PubMed1989

[The effect of Co-60 irradiation on the monomer fraction of intraocular PMMA lenses].

Sterile inflammatory reactions of varying degree are a rare, but not uncommon complication after intraocular lens implantation. At present we still do not know the cause of these processes, but we consider two chemical substances at least as risk factors for them: the lens content of monomeric methyl methacrylate, which is present in any lens made from polymethyl methacrylate (Perspex), and the lens content of ethylene oxide, an extremely toxic agent, which is absorbed by the lens during sterilization with this gas. Gaschromatographic investigations show that under sterilization of intraocular lenses by Co60-radiation the lens content of monomeric methylmethacrylate can be reduced drastically. Also, any contamination of the lens by ethylene oxide is avoided. Therefore at least two important arguments speak in favour of this alternative sterilization technique.

Chromatography, Gas↗
PubMed1989

[Primary accuracy limits of Isosit 10 composite after laboratory preparation].

A modern technique of restoring the anatomical shape of teeth by composite-onlays (Isosit-IO) has been investigated by electronic equipments and the results has been described. The border crevice produced by shrinkage due to polymerisation was found to be extremely small. Significant differences were found in the occlusal and vertical plane with 30 microns as average measuring value. Consequently the high clinically importance of this technique results of the material quality.

Acrylic Resins↗
PubMed1988

Reducing the amount of monomers in intraocular lenses through sterilization by gamma radiation.

Sterile inflammatory reactions of varying degrees are a rare, but not uncommon, complication after intraocular lens implantation. At present we still do not know the cause of these processes, but we consider two chemical substances contained in the lens at least as risk factors for them: monomeric methyl methacrylate, which is present in any lens made from polymethyl methacrylate (Perspex), and ethylene oxide, an extremely toxic agent, which is absorbed by the lens during sterilization with this gas. Gas chromatographic investigations show that under sterilization of intraocular lenses by 60Co radiation the amount of monomeric methyl methacrylate in the lens can be reduced drastically. Also, any contamination of the lens by ethylene oxide is avoided. Therefore, at least two important arguments speak in favor of this alternative sterilization technique.

Chromatography, Gas↗