Biomedical subjects

M Höckel

Publications and source records attributed to M Höckel.

81 records · Page 5Linked to original sources

PubMed1977

F1-ATPase from Micrococcus sp. ATCC 398. Purification by ion-exchange chromatography and further characterization. (Auto)proteolysis and dissociative effects.

The preparation of highly purified F1-ATPase from Micrococcus sp. ATCC 398 by application of DEAE-Sepharose CL-6B chromatography as final step is described. This enzyme consists of five subunits of different molecular weight: alpha (65000), beta (55000),gamma (35000), delta (20000), and epsilon (17000). Disc electrophoresis on 5% polyacrylamide gels removes the epsilon-polypeptide yielding an active ATPase complex with four different subunits: alpha, beta, gamma, delta. Additionally, by variation of the ionic strength delta can (partly) removed allowing the isolation by disc electrophoresis of an active ATPase complex which consists only of three different subunits alpha, beta, and gamma. If the DEAE-Sepharose chromatography is carried out in the absence of diisopropyl phosphofluoridate (auto)proteolysis yields both an active ATPase with the subunits alpha+ (mol. wt 61000), beta, gamma, and delta and an inactive protein complex with the subunits alpha+, beta, gamma, delta, and two additional polypeptides a (mol. wt 38000) and b (mol. wt 23000). The latter two polypeptides are supposedly fragments of alpha+-chains which have become partially cleaved by (auto)proteolysis.

Adenosine Triphosphatases↗

PubMed1976

Membrane-bound F1 ATPase from Micrococcus Sp. ATCC 398E. Purificationa and characterization ny affinity chromatography.

A chemically reactive ATP analogue, 6-[(3-carboxy-4-nitrophenyl)thio]-9-beta-D-ribofuranosylpurine 5'-triphosphate (Nbs6ITP) has been synthesized. It has the ability to form stable thioether bonds between the 6-position of the purine ring and aliphatic mercapto groups. The nucleotide moiety of the reagent has been covalently bound to agarose, via iminobispropylamine and N-acetyl-homocysteine as space with the purpose of producing an affinity chromatography material. The affinity matrix binds solubilized F1 ATPase from a crude extract of Micrococcus sp. membranes. Afterwards the enzyme can be selectively eluted from the column at a defined ATP concentration. This method is superior to the conventional purification with respect to speed and convenince of the preparation. The affinity chromatography leads in a one-step process to the same purity to enzyme, substituting several steps of the conventional method. In addition, the affinity matrix was used for binding studies. Although the presence of Mg2+ ions is a prerequisite for the hydrolysis of nucleoside 5'-triphosphates, evidence is presented indicating that the binding of the nucleoside triphosphates to highly purified F1 ATPase from Micrococcus sp. appears not to be influenced by Mg2+ ion concentrations so far examined.

Adenosine Triphosphatases↗

PubMed1976

Me2+-(13 S) ATPase from Micrococcus sp. ATCC 398E. The effect of trypsin on the purified enzyme.

By trypsin treatment of highly purified ATPase (EC 3.6.1.3) from Micrococcus sp. ATCC 398E, two enzyme modifications have been obtained. (i) ATPase Ta, which has about the same activity as untreated ATPase. (ii) A protein complex Ti, which lacks ATPase activity, but nevertheless binds ATP as shown by affinity chromatography. Trypsin primarily shortens the alpha-chains of the "native" enzyme to alpha-chains and removes the gamma-subunit, thus yielding ATPase Ta. The formation of the protein complex Ti appears to be due to additional cleavage of one alpha-chain into at least two more fractions.

Adenosine Triphosphatases↗

PubMedDate not supplied

The presence of HPV DNA in cervical cancer: correlation with clinico-pathologic parameters and prognostic significance: 10 years experience at the Department of Obstetrics and Gynecology of the Mainz University.

The objective of this study was to assess whether the presence of human papillomavirus (HPV) DNA and/or several genotypes of HPV DNA in cervical cancer are correlated with several clinicopathologic parameters of well-defined prognostic significance and whether virologic parameters are predictors of long-term survival in cancer patients. Two hundred twenty three cases of cervical cancer patients included in this retrospective study underwent follow-up evaluation. Survival and cause of death were examined for 204 (91.4%) patients, with a mean follow-up time of 4.4 years. HPV DNA was detected using the highly sensitive polymerase chain reaction (PCR) method followed by HPV DNA sequencing for HPV genotyping. These results were correlated with well-defined clinicopathologic parameters and survival data. HPV DNA was detected by PCR in 150 of 193 (73.4%) tissue specimens of cervical cancer patients. DNA sequence analysis revealed the presence of HPV 16 (n = 68, 45.3%), HPV 18 (n = 49, 32.6%) and rare HPV types (n = 33, 22.1%). HPV genotypes correlated significantly with histologic tumor types, node status, tumor oxygenation, blood vessel invasion, and lymph space involvement. The presence of HPV DNA in cervical cancer as well as the genotype of HPV 16 could also be confirmed as significant prognostic factors in the univariate Cox regression analysis (RR 2.856, P < 0.003 resp. RR 3.444, P < 0.0001). In the multivariate analysis, however, HPV DNA status failed to be of prognostic relevance. Exclusively HPV 16 appears to have an independent impact on the overall survival in cervical patients (RR 3.653, P < 0.002). We conclude that the detection of HPV 16 genotype may play an important adjunct role in assessing prognosis of cervical cancer patients. The clinical impact of the presence of HPV DNA in primary tumors of uterine cervix remains to be investigated in further studies, and the exact mechanisms by which HPV influences the prognosis of cervical cancer patients have to be defined.

Adenocarcinoma↗

PubMedDate not supplied

Occult tumor cells in surgical specimens from cases of early cervical cancer treated by liposuction-assisted nerve-sparing radical hysterectomy.

Tumor recurrence in patients with cervical cancer after primary radical surgery with complete tumor resection (R0) may be caused by occult tumor cell deposits (OTCD) in potentially tumor-bearing pelvic tissue. New surgical techniques, like liposuction-assisted nerve-sparing radical abdominal hysterectomy (LANS-RH) might be performed to remove this tissue. In a preliminary study of 30 cases, treated with LANS-RH, the liposuction specimens were examined on hematoxylin & eosin (H&E)-stained step sections and at immunohistochemical levels, using the antibody cocktails MNF 116 and AE1/AE3 for cytokeratins to detect occult tumor cells. In nine cases microscopically tumor-free lymph nodes were detected in the liposuction material. One case presented lymphovascular space involvement in the capsular region of a node on H&E stained slides. Two additional cases showed tumor cell deposits in pelvic perinodal fatty tissue on immunohistochemical examination. We conclude that the LANS-RH technique is capable of resecting potentially tumor-bearing pelvic tissue. Careful histologic handling and immunohistochemical techniques may improve the detection of OTCD.

Abdomen↗

PubMedDate not supplied

Total mesometrial resection: high resolution nerve-sparing radical hysterectomy based on developmentally defined surgical anatomy.

Total mesometrial resection (TMMR) is characterized by: i). the en bloc resection of the uterus, proximal vagina, and mesometrium as a developmentally defined entity; ii). transection of the rectouterine dense subperitoneal connective tissue above the level of the exposed inferior hypogastric plexus; and iii). extended pelvic/periaortic lymph node dissection preserving the superior hypogastric plexus. Since July 1998 we have studied prospectively the outcome in patients treated with TMMR for cervical carcinoma FIGO stages IB, IIA, and selected IIB. By July 2002, 71 patients with cervical cancer stages pT1b1 (n = 48), pT1b2 (n = 8), pT2a (n = 3), pT2b (n = 12) had undergone TMMR without adjuvant radiation. Fifty-four percent of the patients exhibited histopathologic high risk factors. At a median observation period of 30 months (9-57 months) two patients relapsed locally, two patients developed pelvic and distant recurrences and two patients only distant recurrences. Three patients died from their disease. Grade 1 and 2 complications occurred in 20 patients, no patient had grade 3 or 4 complications. No severe long-term impairment of pelvic visceral functions related to autonomic nerve damage was detected. Based on these preliminary results, we believe TMMR achieves a promising therapeutic index by providing a high probability of locoregional control at minimal short and long-term morbidity.

Adult↗

PubMedDate not supplied

Hypoxia and expression of the proapoptotic regulator BNIP3 in cervical cancer.

Hypoxia plays a major role in the malignant progression of tumors. Here, we investigate the expression of Bcl-2/adenovirus E1B 19 kd-interacting protein 3 (BNIP3), a proapoptotic Bcl-2 family member, and its relationship to hypoxia in cervical cancer cell lines and clinical samples of cervical cancer. Cervical cancer cell lines were grown under hypoxia or normoxia, and BNIP3 mRNA expression was examined by Northern blot analysis. In 50 patients with cervical cancer, intratumoral oxygen measurement with the Eppendorf electrode and needle biopsies of the tumor were performed. The obtained tissue was subsequently analyzed by immunohistochemistry with an anti-BNIP3 antibody. Cervical cancer tissue collected upon surgery was used for Northern blot analysis of in vivo BNIP3 mRNA expression. BNIP3 mRNA is strongly induced under hypoxic conditions in all cervical cancer cell lines investigated. Furthermore, Northern blot analysis revealed that BNIP3 mRNA is expressed in cervical cancer tissue. Using immunohistochemistry, we demonstrated that BNIP3 protein is expressed in 82% of the investigated cervical cancers and that more advanced tumor stages showed significantly stronger BNIP3 expression. However, we observed no correlation between BNIP3 expression and intratumoral hypoxia. In conclusion, BNIP3 is expressed in different cervical cancer cell lines as well as in clinical samples of cervical cancer. Although BNIP3 is clearly hypoxia-inducible in vitro, our results suggest additional mechanisms of BNIP3 regulation in vivo. Our findings therefore highlight a discrepancy between in vitro models of tumor hypoxia and the complexity of human cancer.

Carcinoma↗

PubMedDate not supplied

[Degree of placental maturity and histopathologic finding: clinical prospective studies of a sample of term births and premature births].

By analogy with Grannum et al.'s sonographic classification of the placenta (1979), macroscopic observation of the cut surfaces of the afterbirth enables the extent of placental segmentation to be determined and macroscopic maturity to be established in accordance with sonographic findings. Out of a total of 767 clinically-prospectively documented obstetrical cases, 674 were identified as term births and 93 as premature. For the purposes of comparison they were subdivided into two groups: term births with stage 0 to II and stage III maturity; and premature births with stage 0 to II and stage III maturity. Proceeding from this morphological classification and grouping, the clinical data, such as age of the mother, parity, gravidity, diseases during pregnancy, premature labour, type of delivery, fetal outcome, and biometric data of the newborn, as well as histologic findings regarding villous maturity, were recorded and statistically analyzed. The findings revealed no significant differences between term births with stage III maturity and those in the control group of placentas with stage 0 to II maturity and the same gestation time. Therefore, stage III maturity at term corresponds chronopathologically to a normal temporal development of fetomaternal flow units of the mature human placenta at term and does not imply any perinatological risk. Histopathologically, placentas with stage III maturity manifest a significantly advanced degree of villous maturity, with lower mean placental weight as the morphological correlate to threshold placental function, which is reflected in the clinical data of perinatological complications. Therefore, premature detection of a stage III placenta before term indicates a risk that should be kept in mind in the overall concept of prenatal monitoring parameters.

Chorionic Villi↗

PubMedDate not supplied

[Premature cervical ripening--surgical or conservative therapy?].

We studied the effect of the cerclage operation as treatment of premature ripening of the cervix in the 15.-35. week of gestation with a retrospective matched pair analysis (n = 142). For each patient in the group treated operatively (n = 71) a patient was selected, who was clinically comparable in parity, gestational age and cervix score at the time of diagnosis but was managed conservatively (n = 71). The study showed that the cerclage operation is not generally advantageous as treatment of premature cervical ripening. Because of the higher perinatal morbidity in the group treated by an operation, the unselected indication for a therapeutical cerclage is questioned. To define indications for cervical cerclage as operative treatment for premature cervical ripening we selected subgroups by history and clinical data treated either operatively or conservatively and evaluated their parameters of gestation, delivery and puerperium as well as the perinatal outcome. We found that the operative treatment was superior to the conservative therapy only in patients with premature cervical ripening before the 25th week of gestation and in patients with an "open cervix" and a history of miscarriage, abortion or premature delivery. The results of this study led to a proposal for the treatment of patients with premature ripening of the cervix, which has to be confirmed by prospective controlled studies.

Adult↗