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Biomedical subjects

K Meissner

Publications and source records attributed to K Meissner.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of HIV-1 infection in vitro by murine monoclonal anti-p24 antibodies.

Murine monoclonal antibodies (Mabs) to the major core protein p24 of the human immunodeficiency virus type 1 (HIV-1) were tested for their ability to inhibit the replication and spread of the virus in permanent cell cultures (Molt4/8, K37, H9) and in the culture of II-2 stimulated T cells of healthy donors. After addition of ascitic fluid containing monoclonal anti-p24 antibodies or purified anti-p24 antibodies or the respective control to co-cultures of infected and non-infected cells, HIV-1 replication was evaluated by determining the percentage of infected cells and the activity of reverse transcriptase (RT) in cell-free supernatant. In addition, the supernatant's infectivity was determined. FACS analysis demonstrated p24 antigen in about 40% of unfixed HIV-1 infected cells at the cell membrane. Monoclonal anti-p24 antibodies of different epitope specificity added to the cells but not to the virus delayed the spread of HIV-1 infection in permanent cell culture. Furthermore, anti-p24 Mabs inhibited the release of RT-active virus particles by HIV-1 infected cell lines or II-2 stimulated T-lymphocytes, respectively, up to 60%. The mode of action of anti-p24 antibodies after HIV-1 infection is discussed on the basis of the data obtained.

Animals↗
PubMed1992

Topoisomerase activity in mitochondrial lysates of a higher plant (Chenopodium album L.).

We describe an in vitro system for detection of topoisomerase activity from lysed mitochondria. Mitochondria were isolated from a suspension of cultured Chenopodium album cells. We observed a high activity in relaxation of negatively supercoiled DNA (pBR322). Addition of ATP had no effect on the activity. Topoisomers obtained from negatively supercoiled DNA were identical with topoisomers produced by the topoisomerase I of E. coli. The mitochondrial activity was dependent on the presence of Mg2+ ions and could be inhibited by novobiocin and N-ethylmaleimide. Nalidixic acid and berenil had no influence on the mitochondrial topoisomerase activity. These features characterize the enzyme as a type I topoisomerase.

Cells, Cultured↗
PubMed1990

Study of neu-protein expression in mammary Paget's disease with and without underlying breast carcinoma and in extramammary Paget's disease.

Correlation between neu/c-erbB-2/Her-2 gene amplification and overexpression of the neu gene product has been reported in tumors of glandular origin, especially ductal breast carcinomas. Formalin-fixed and dewaxed sections from 23 cases of mammary (MPD) and 9 cases of extramammary (EPD) Paget's disease were immunohistochemically stained by means of the monoclonal antibody 3B5 directed against an intracellular domain of the neu gene protein. All MPDs exhibited a distinct membrane staining of tumor cells independent of the presence of ductal breast carcinomas found in 18 cases. All these breast carcinomas also were positive for neu staining. In contrast to MPD, all EPDs were negative. Normal epidermis was always negative. Northern blot analysis sustained the immunohistologic findings in that the presence of neu mRNA could be demonstrated in two of three cases with MPD. Negativity in one case was due to dilution effects by nontumor cells. Our results suggest that Paget cells of mammary and extramammary localization, although very similar phenotypically, derive from different genetic accidents. Furthermore neu positivity in all MPDs and all underlying ductal carcinomas suggests common genetic alterations for both tumors. However the finding of five neu protein-positive MPDs without associated ductal breast carcinomas may suggest a somewhat different transformation process.

Breast Neoplasms↗
PubMed1978

[Conservative treatment of intestinal obstruction: prospects and limits. Experiences with 27 cases treated by Miller-Abbott-tubes inserted endoscopically (author's transl)].

27 cases of intestinal obstruction primarily treated conservatively by means of Miller-Abbott-tubes are presented, technical details, clinical results, indications and risks of the procedure discussed. The controlled placement of the tube using a gastroscope rules out technical failures. Fifteen patients were cured, 2 patients removed the tube; in 8 cases the procedure turned out to be ineffective; they were cured by laparotomy. The separate monitoring of gastric and intestinal secretion permits early prognosis in respect to efficacy. Two patients died. Strict limitation of indication is of decisive importance. The method is highly effective in early postoperative intestinal obstruction--apparently of mechanical as well as of paralytic origin. In our experience, the possible mistaking of anastomotic leakage for postoperative ileus is practically negligible. For acute admissions with intestinal obstruction of unclear origin, however, the procedure should only be aimed at the resotration of general condition before surgery. In spite of the fact, that some cases of late postoperative intestinal obstruction could be cured conservatively, the risk of delaying operations of utmost necessity in cases of strangulation, incarceration and perforation is too high.

Adolescent↗
PubMed1978

[Closed intestinal decompression in postoperative paralysis: intestinal intubation (author's transl)].

Paralytic distension is a causative or important factor in the pathogenesis of early postoperative intestinal obstruction. The elimination of intestinal distension initiates a decisive change in the course of this disease. The long intestinal tube--comparable to an "intraluminary stoma"--renders the necessary intestinal decompression. The controlled placement of the tube using a gastroscope rules out technical problems. The procedure is highly effective, contributes to the reduction of relaparotomies, and avoids enterotomies with all their inherent risks in the state of ileus.

Gastroscopy↗
PubMed1978

The effective placement of Miller-Abbott-tubes under endoscopic guidance. Technical improvements.

In an earlier publication, the intestinal placement of Miller-Abbott-tubes using routine gastroscopic equipment was proposed for the conservative treatment of intestinal obstruction. In addition to the technical advices presented at this early stage of personal experience, we now recommend to 1. insert the tube primarily through the nostrils, 2. extract the tip through the mouth, 3. grasp the leading ligature of the tube tip extracorporally by means of the biopsy instrument and 4. guide the tube tip to the target area by orogastric approach. This technical improvement excludes difficulties in respect to patient cooperation or other special disadvantages and made 26 intestinal intubations in an uninterrupted series an easy and worthwhile procedure.

Endoscopy↗
PubMed1978

[Secondary acute cholecystitis (author's transl)].

A case of acute postoperative cholecystitis following subtotal gastrectomy for carcinoma has been observed. The combination of temporary intraoperative shock and probably vagal denervation of the gallbladder initiated secondary acute cholecystitis. After an emergency type cholecystectomy the patient recovered.

Aged↗
PubMed1977

[Closure of instrumental perforation of the stenotic esophagus by means of endo-esophageal tube. On the way from solitary success to clinical principle? (author's transl)].

Instrumental perforation, consequential to esophagoscopic diagnostic or therapeutic procedures, ranges among the inherent and life threatening complications of such manoeuvres. Emergency operations in this situation are dangerous and bedeviled with a prohibitive percentage of mortality. Further spillage into the mediastinum was successfully prevented by introducing an endoesophageal tube of the Celestin-type. Antibiotic protection proved to be the only necessary additional measure.

Aged↗
PubMed1977

[Absorbable suture material in the surgery of the biliary tract (author's transl)].

Conventional unabsorbable suture material can lead to gall salt precipitation and thus to gall stone formation. Catgut segments may cause identical sequelae if they are displaced into the lumen of the biliary tract under certain conditions. The reaction of polyglycolic acid (PGA) as well as of polyglactin material was tested under in-vitro conditions. PGA material disintegrated within 9 weeks; precipitation of gall salts was not observed. Polyglactin samples showed stable durability up to 22 weeks under the same conditions; firmly adherent small concrements could be demonstrated. In accordance with these observations, PGA material seems to be the most appropriate suture material for the surgery of the biliary tract at the time being.

Biliary Tract Surgical Procedures↗
PubMed1976

[Investigations of polycyclic aromatic hydrocarbons in cigarette smoke (author's transl)].

Polycyclic aromatic hydrobarbons (PAH), which are responsible for most of the carcinogenic activity of cigarette smoke were isolated from smoke condensate by distribution steps and chromatographic methods. The fractions containing substances in the range fluorence to chrysen were investigated by gaschromatography and mass-spectrometry. 150 substances were characterized. Unsubstituted PAH, alkyl-substituted PAH and O-heterocyclic compounds were identified.

Carcinogens↗
PubMed1976

[Massive hemorrhage caused by acute solitary gastric erosion Dieulafoy. Change of prognosis due to preoperative endoscopy (author's transl)].

In this report of three successfully operated cases of acute solitary gastric erosion--Ulcus Dieulafoy (U.D.), the anatomical and clinical characteristics of this rare gastric lesion are discussed. Due credit is given to reports of the literature. As born out by experience, conservative treatment of bleeding U.D. is usually lethal. Judged from statistical evaluation, surgical intervention has proven to be unsuccessful in many cases. This is directly related to the problem of intraoperative localisation, which, in turn, may lead to illadvised procedures. With acurate localisation of the lesion, surgical management yields good to excellent results. Acute endoscopy as a routine procedure in gastrointestinal hemorrhage in our experience is the key to success, leading to a possibly decisive change in the prognosis of U.D.

Acute Disease↗
PubMed1976

[Intestinal placement of Miller-Abbott-tubes under endoscopic guidance (author's transl)].

Based on experiences with 9 treatments in 7 cases of intestinal obstruction, the technique of endoscopic transgastric guidance of Miller-Abbott-tubes is reported. On our service, the above mentioned method was applied in the treatment of intestinal obstruction observed in cases of advanced malignant lesions as well as in patients with intestinal obstruction in the early postoperative period. Apparative aids and technical guidelines are accentuated. The method requires a team consisting of at least one physician and three assistents with clearly defined competence. Success also depends on the selection of material used. Special problems arise in the treatment of patients following partial gastrectomy. Routine X-rays are important in order to control the course of treatment and to documentate the result. The inclusion of endoscopic aids resulted in successful intestinal intubation in all cases treated. The utilization of recommended guidelines seemingly rules out technical failure in the attempt of placing the tube in the desired anatomic position.

Adult↗
PubMed1976

[New formation of gallbladder calculi due to suture material--avoidable problem?].

Catgut material has proved to be perfectly stable in gall, thus facilitating precipitation and calculus formation. Therefore, polyglycolic acid suture material was tested under laboratory conditions. This material disintegrates completely within 9 weeks, and for this reason is recommended in operations on the biliary tract.

Cholelithiasis↗