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Biomedical subjects

C Mohr

Publications and source records attributed to C Mohr.

At least 55 records · Page 3Linked to original sources

[Early detection of threatened implant loss in tumor patients].

After resection of an oropharyngeal tumor, 157 dental implants were placed in 17 irradiated (44 Gy on average) and 20 non-irradiated patients. Within a control period of 37 months, 15 implants had failed. The reason for implant failure was analyzed, whereby indicative parameters were revealed. Eleven implants in four irradiated and one non-irradiated oral cancer patients showed no primary osseointegration during the healing period because of mandible fracture, overloading or for unknown reasons. Four implants in one irradiated and three non-irradiated oral-cancer patients were lost subsequently on average 39 months after second-stage surgery due to biomechanical overloading or bacterial infection. No osteoradionecrosis development due to implant failure was observed in irradiated patients. In all cases, peri-implant pocket depth, implant stability and peri-implant bone resorption increased before definitive implant failure. Therefore, these findings seem to be useful as indicative parameters in the prediction of implant failure.

Adult↗

[Suppurative abscess-forming mediastinitis after tooth extraction. Consequences for therapeutic approach].

Purulent mediastinitis is a rare but serious complication of a descending odontogenic infection with a high mortality. Diagnosis is difficult and frequently delayed. Physical examination is often nondiagnostic, but may include pronounced edema of the neck and chest. CT scan is the single most important tool for early diagnosis. The treatment is always is surgical, in combination with an extremely high dose of combined antibiotics. Ultimately, we only could save our patient with this therapy.

Abscess↗

Evaluation of oro-coecal transit time: a comparison of the lactose-[13C, 15N]ureide 13CO2- and the lactulose H2-breath test in humans.

OBJECTIVE: The lactulose H2-breath test is the most widely used non-invasive approach for evaluation of orocoecal transit time (OCTT). In the present study, doubly-labelled lactose-[13C, 15N]ureide (DLLU) was synthesized to investigate the OCTT in comparison to the conventional lactulose H2-breath test. Additionally the bacterial breakdown rate (BBR) and rate of elimination and the metabolic pathways of the cleavage products of DLLU (13CO2, [15N]urea, and 15NH3) were investigated. DESIGN AND SUBJECTS: In a first study, DLLU was administered as a single oral-pulse-labelling (dosage: one gram) either without and after pretreatment of five grams of unlabelled lactoseureide (LU) on the day prior to the study to twelve healthy adult volunteers after breakfast. Breath and urine were collected in one and two hour-intervals, respectively, over a one-day period. 13C-enrichment in breath as well as 15N-enrichment in urine fractions were measured by continuous flow-isotope ratio mass spectrometry (CF-IRMS). In a second study, lactulose was administered to the same subjects (dosage: ten grams). Breath was collected in quarter, half and one hour-intervals over a ten hour-period. Hydrogen concentration in breath was analysed using an electrochemical detector. RESULTS: The comparison of the lactose-[13C]ureide 13CO2-breath test and the lactulose H2-breath test showed that the mean increase of the 13C-enrichment in CO2 occurred 1.18 h later than the mean increase of H2 in breath. The resulting OCTTs derived from the two methods were 3.02 +/- 1.4 and 1.84 +/- 0.5 h (P < 0.05) and the corresponding BRs were 9.63 +/- 3.4 and 6.07 +/- 1.7 h (P < 0.01), respectively. The 15N-enrichment of urinary urea and ammonia without and after pretreatment with LU started between two and three hours after DLLU-administration. The cumulative percentage urinary excretion of the 15N- and 13C-tracer was 29.9% and 13.6% respectively, and was slightly increased after LU-pretreatment to 32.1% and 14.6% of the dose administered. A total of 35.2% of the 13C was found to be exhaled and remained approximately constant after LU-pretreatment (36.2%). CONCLUSIONS: The use of the lactulose H2-breath test for evaluation of the OCTT showed a statistically significant shortening of 1.18 h in comparison to the lactose-[13C]ureide 13CO2-breath test in healthy adults. The most important limitations of the lactulose H2-breath test are its low specificity and sensitivity due to dose-dependent accelerations of OCTT, interfering H2-rise from malabsorbed dietary fibre and H2-non-producers. In contrast, our lactose-[13C]ureide 13CO2-breath test was confirmed to avoid these disadvantages and to yield reliable results. This test is recommended especially if higher sensitivity and specificity is required, if IRMS-technique is available and if lactulose H2-tests lead to insufficient results.

Breath Tests↗

"Latex-fruit syndrome": frequency of cross-reacting IgE antibodies.

An association between allergies to latex proteins and to various foods has been reported and confirmed by RAST and immunoblotting inhibition. However, no significant data had been collected on the frequency of specific IgE antibodies to fruits in these patients and the frequency of a history of fruit intolerance. Serum samples of 136 patients with well-documented, clinically relevant, immediate-type hypersensitivity against latex proteins were analyzed for IgE antibodies against a panel of different fruits. Patient history of food intolerance was documented by a standardized questionnaire. Fruit-specific IgE antibodies were detected in 69.1% of serum samples. Cross-reacting IgE antibodies recognizing latex and fruit allergens (papaya, avocado, banana, chestnut, passion fruit, fig, melon, mango, kiwi, pineapple, peach, and tomato) were demonstrated by RAST-inhibition tests. Of our patients, 42.5% reported allergic symptoms after ingestion of these fruits and a total of 112 intolerance reactions were recorded. However, fruit-specific IgE antibodies were detected only in serum samples from 32.1% of the patients who perceived symptoms due to these fruits. Thus, serologic tests seem to be of low significance for prediction o food allergy in latex-allergic patients.

Adolescent↗

Identification of the fliI and fliJ components of the Caulobacter flagellar type III protein secretion system.

Caulobacter crescentus is motile by virtue of a polar flagellum assembled during the predivisional stage of the cell cycle. Three mutant strains in which flagellar assembly was blocked at an early stage were isolated. The mutations in these strains mapped to an operon of two genes, fliI and fliJ, both of which are necessary for motility. fliI encodes a 50-kDa polypeptide whose sequence is closely related to that of the Salmonella typhimurium FliI protein, an ATPase thought to energize the export of flagellar subunits across the cytoplasmic membrane through a type III protein secretion system. fliJ encodes a 16-kDa hydrophilic protein of unknown function. Epistasis experiments demonstrated that the fliIJ operon is located in class II of the C. crescentus flagellar regulatory hierarchy, suggesting that the gene products act at an early stage in flagellar assembly. The expression of fliIJ is induced midway through the cell cycle, coincident with other class II operons, but the FliI protein remains present throughout the cell cycle. Subcellular fractionation showed that FliI is present both in the cytoplasm and in association with the membrane. Mutational analysis of FliI showed that two highly conserved amino acid residues in a bipartite ATP binding motif are necessary for flagellar assembly.

Amino Acid Sequence↗

[Molluscum contagiosum-like papules within the scope of disseminated infection with Mycobacterium avium complex in an AIDS patient].

A 38-year-old HIV-positive man had several attacks of high fever associated with extensive perspiration over a 10-week period. Simultaneously, he developed molluscum contagiosum-like papules and an erythematous plaque on the face, ulcerated papules on both shoulders and buttocks and subcutaneous nodules on the arms. Histological examination of biopsy specimens revealed a diffuse, histiocytic infiltrate with abundant rod-shaped bacteria. Mycobacterium avium complex was cultured from the tissue and Mycobacterium avium complex DNA was detected by the polymerase chain reaction. The diagnosis of disseminated disease was additionally confirmed by culturing Mycobacterium avium complex from blood, sputum and stool. The skin lesions healed completely within 10 weeks by a multiagent as the patient was treated with a drug therapy. We describe the differential diagnosis, diagnostic procedures and therapy of disseminated infection with Mycobacterium avium complex.

AIDS-Related Opportunistic Infections↗

Inhibition of LPS-induced tumor necrosis factor-alpha production by colchicine and other microtubule disrupting drugs.

Colchicine has been shown to act as an antiinflammatory agent. In this study, we examined whether colchicine and other microtubule-depolymerizing drugs affected the production of TNF-alpha. When rat peritoneal macrophages were stimulated by LPS, addition of colchicine, vincristine, vinblastine or nocodazole was found to inhibit TNF-alpha release in a concentration-dependent manner. Suppression of TNF-alpha release was not due to interference with secretion as the cytokine did not accumulate intracellularly following colchicine treatment. Colchicine markedly enhanced PGE2 release from LPS-stimulated macrophages. However, addition of the cyclooxygenase inhibitor indomethacin only partially reversed the suppressive effect of colchicine on TNF-alpha production. Colchicine caused a strong reduction of LPS-induced TNF-alpha mRNA accumulation, suggesting that a pretranslational effect may represent the primary mechanism by which colchicine reduced TNF-alpha production. These observations could have clinical relevance in ameliorating undesirable effects due to excessive TNF-alpha production, for example following LPS stimulation of monocytes/macrophages in gram-negative sepsis. Furthermore, these drugs may provide useful tools to study the apparent involvement of the microtubular system in cytokine gene expression and cytokine production.

Animals↗

Suppression of LPS-induced tumor necrosis factor-alpha gene expression by microtubule disrupting agents.

Microtubule disrupting agents such as colchicine have been shown to reduce TNF-alpha production in macrophages. To examine molecular mechanisms underlying the action of colchicine, TNF-alpha gene expression was studied in the murine macrophage cell line PU5-1.8. An LPS stimulation caused an intense up-regulation of TNF-alpha gene expression which was followed by a high TNF-alpha protein production. Simultaneous addition of colchicine (10 microM) suppressed LPS-induced TNF-alpha mRNA accumulation by one-third and TNF-alpha protein release by two-thirds. This effect was shared by vinblastine and vincristine, chemically different agents that also disrupt microtubule polymerization. For full suppressive activity on TNF-alpha gene expression, colchicine had to be present for 3 h in LPS-stimulated macrophage cultures. With nuclear run-on transcription experiments we could demonstrate that colchicine primarily inhibited de novo gene transcription and did not accelerate degradation of TNF-alpha mRNA in actinomycin D-treated macrophages. Thus, the well-known antiinflammatory action of microtubule depolymerizing agents may be largely due to a reduced TNF-alpha gene expression.

Animals↗

Innervation patterns of the lateral line stitches of the clawed frog, Xenopus laevis, and their reorganization during metamorphosis.

We quantitatively examined the afferent innervation pattern of the lateral line stitches of both larval and postmetamorphotic clawed frogs, Xenopus laevis, using a silver staining technique. We also studied the relevance of the number of neuromasts in a stitch to physiological properties, recording afferent activity with an electrode inserted directly into the neuromast. The innervation pattern changed during early metamorphosis, the fiber thickness increasing after the reorganization. We found three different innervation patterns: in type A stitches, the same two afferent fibers innervate all neuromasts; in type B stitches, one or two fibers innervate more than one stitch; in type C stitches, three to six fibers innervate a stitch. The distribution of the different types of stitches varied in different parts of the body. The frequency of type A stitches differed between larval trunk and larval head. For both larvae and juveniles, type B stitches were more frequent on ventral than dorsal areas, while type C stitches were more frequent on the head than on the trunk. Electrophysiological experiments indicated that the sensitivity of an afferent fiber increases with the number of neuromasts it innervates. This increase and the variation in innervation patterns shows that the single afferent fiber, not the stitch, is the functional unit of the lateral line periphery.

Afferent Pathways↗

[Long-term outcome after intraoral miniplate osteosynthesis in mandibular angle fractures].

The success or failure of intraoral miniplate osteosynthesis is mainly influenced by right indication. More than 90% of the fractures of the mandible were treated successfully by intraoral noncompressive miniplate osteosynthesis. Hence a postoperative intermaxillar fixation seems not to be necessary. Considering the range of indication this is an effective method of no complications. Nevertheless an immobilisation for one week is accepted by our patients without any problems and is recommended according to normal healing. The collective of our patients in Essen is selected as unilateral multiple fractures, comminuted fractures and infected fractures of the mandible were not treated by miniplate osteosynthesis.

Adolescent↗

Enhancement of lysozyme trypsin-mediated decay of intestinal bifidobacteria and lactobacilli.

Lysozyme-mediated lysis of Bifidobacteria and Lactobacilli was studied in in vitro tests using the agar gel plate and turbidometric Micrococcus luteus (lysodeikticus) procedure as a standard. Suspensions of the strains Bifidobacterium infantis, B. infantis liberorum, B. breve, B. longum, B. ssp, and Lactobacillus acidophilus proved to be resistant to egg white lysozyme and human milk lysozyme when incubated at 37 degrees C in concentrations of 5, 50, and 500 mg lysozyme/L, respectively, through 30 and 60 min. Heat treatment at 100 degrees C for 1 h and pretreatment with ether, acetone, ascorbic acid, and hydrogen peroxide failed to incline the bacteria to the lytic effects of lysozyme. Consecutive incubation of the lysozyme-pretreated bacteria with trypsin resulted in a significantly enhanced bacteriolysis in all strains of bacteria, with the exception of B. longum. The mode of action of lysozyme and proteolytic enzymes on Bifidobacteria and Lactobacilli offers an explanation for the release of microbial building blocks and their colonic absorption and retention in the breast-fed baby.

Acetone↗

Successful treatment of epidermolysis bullosa acquisita using intravenous immunoglobulins.

We report a 55-year-old man with severe inflammatory epidermolysis bullosa acquisita. The skin lesions did not respond to various immunosuppressive treatments. The combined administration of prednisone, azathioprine, dapsone and colchicine resulted only in a transient and incomplete resolution of the lesions. The bullae and increased skin fragility were successfully controlled by the addition of high-dose intravenous immunoglobulin therapy.

Azathioprine↗

Eosinophilic pustular folliculitis: successful treatment with interferon-alpha.

Eosinophilic pustular folliculitis (Ofuji's disease) is a rare skin disease of unknown etiology characterized by infiltrated circinate plaques with sterile follicular pustules in primarily seborrheic areas. Several therapeutic regimens have been reported to control the disease with inconsistent results. We here report on a patient with Ofuji's disease, who was successfully treated with interferon-alpha 2b.

Adolescent↗

[Dental treatment before radiotherapy of carcinoma of the mouth floor].

Two collectives of patients who required radiation therapy were built. In order to determine the adequate occasion and extension of surgical teeth restoration in dependence on radiation therapy, both collectives were compared. The first group implicated 21 manifest ORN. The triggers of these ORN were evaluated. In the second collective the ORN occurrence after 225 generous surgical teeth restorations before radiation therapy were prospectively fixed and analysed. In comparison of both collectives the concept of generous removing of all potential dentogene inflammations before radiation therapy was successful in prevention of the septic ORN.

Humans↗

Preoperative radiochemotherapy and radical surgery in comparison with radical surgery alone. A prospective, multicentric, randomized DOSAK study of advanced squamous cell carcinoma of the oral cavity and the oropharynx (a 3-year follow-up).

A multicentric, randomized study of squamous cell carcinoma (SCC) of the oral cavity and the oropharynx has been undertaken by DOSAK. The results after radical surgery alone have been compared with the results of combined preoperative radiochemotherapy followed by radical surgery. Patients with primary (biopsy proven) SCC of the oral cavity or the oropharynx with tumor nodes metastasis (TNM) stages T2-4, N0-3, M0 were included in the study. A total of 141 patients were treated by radical surgery alone, whereas 127 patients were treated by radical surgery preceded by preoperative radiochemotherapy. The preoperative treatment consisted of conventionally fractioned irradiation on the primary and the regional lymph nodes with a total dose of 36 Gy (5 x 2 Gy per week) and low-dose cisplatin chemotherapy with 5 x 12.5 mg cisplatin per m2 of body surface during the first week of treatment. Radical surgery according to the DOSAK definitions (DOSAK, 1982) was performed after a delay of 10-14 days. During the follow-up period, 28.2% of all patients suffered from locoregional recurrence, and 27.2% of the patients died. The percentages were higher after radical surgery alone for locoregional recurrence (31% and 15.6%) and for death (28% and 18.6%). The life-table analysis showed improved survival rates of 4.5% after 1 year and 8.3% after 2 years in the group of patients treated with combined therapy. The demonstrated improvement appeared to be significant with the Gehan-Wilcoxon test as well as with the log rank test below a P value of 5%.

Carcinoma, Squamous Cell↗