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Biomedical subjects

H Maier

Publications and source records attributed to H Maier.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Syndrome of the anterior spinal artery as the primary manifestation of aspergillosis.

Aspergillosis of the central nervous system (CNS) is an uncommon infection, mainly occurring in immunocompromised patients. Beside cerebral involvement spinal cord lesions are extremely rare. To our knowledge, aspergillosis initially presenting with acute paraplegia due to mycotic thrombosis of the anterior spinal artery in a formerly healthy patient has, so far, not been reported. Neither a primary focus nor an underlying disease had been detected.

Acute Disease↗
PubMedDate not supplied

Effect of alcohol on gastrointestinal cell regeneration as a possible mechanism in alcohol-associated carcinogenesis.

Chronic ethanol consumption is a major risk factor for oropharyngeal, esophageal, and rectal cancer. Because hyperregenerative gastrointestinal mucosa has an increased susceptibility towards chemical carcinogens and thus influences carcinogenesis, various studies have been performed to evaluate the effect of chronic ethanol consumption on mucosal cell turnover. In the rat, morphometric analysis showed that in chronically ethanol-fed rats the size of the basal cell nuclei of the oral mucosa from the floor of the mouth, the edge of the tongue, and the base of the tongue were significantly enlarged. The size of the basal cell layer was increased and the stratification of the cells was altered. The percentage of cells in S-phase of the cell cycle was significantly higher in ethanol-fed rats compared to controls. In addition, mucosal atrophy was found. Similar to the oropharynx, in the esophagus chronic ethanol consumption increased cell proliferation depending on salivary gland function, because only in the presence of the salivary glands was this stimulative effect of alcohol on cell turnover found. Subsequently, chronic ethanol ingestion significantly stimulated crypt cell production rate in the rectum, in an age-dependent manner. This hyperregeneration, which was only observed in the rectum but not in the remaining colon, was associated with an expansion of the proliferative compartment of the crypt. Such an expansion is correlated with increased risk for rectal cancer. In addition, crypt cell production rates in the rectal crypts can be correlated with mucosal acetaldehyde concentrations, underlining a toxic effect of acetaldehyde on the rectal mucosa that is answered by compansatory hyperregeneration. These data from the rat model could be confirmed in humans. In conclusion, chronic ethanol consumption leads to mucosal hyperregeneration in gastrointestinal mucosa associated with a high risk for cancer and may therefore be at least one mechanism by which alcohol exerts its cocarcinogenic effect.

Alcohol Drinking↗
PubMedDate not supplied

[Analysis of strength values of the wrist muscles and its clinical relevance].

A lot of injuries in profession and sports concern the hand. Therefore first principles should be elaborated which make it possible to assess such an injury and to define the therapy progress. Concerning this 50 probationers underwent an isokinetic test of the wrist extensors and of the wrist flexors. A close correlation could be determined between torque and work. The highest torque were achieved with the lowest velocity. Dependences could be found out concerning, age and dominant hand, so that these factors have to be considered with an assessment of an injury.

Adolescent↗
PubMedDate not supplied

Induction of renal cell apoptosis by antibodies and complement.

Renal diseases are in many cases associated with the presence of increased numbers of apoptotic cells in the kidney. Apoptosis has been proposed as an important mechanism involved in the resolution of a proliferative response. Furthermore, recent studies indicate its possible involvement in progression of renal disease, leading to sclerosis. Moreover, in an experimental model of acute mesangioproliferative glomerulonephritis in the rat, induced via antibodies directed to Thy-1, evidence was obtained for the occurrence of apoptosis coinciding with the very early induction of mesangial injury. The present review is focused on apoptosis in relation to this model, and discusses recent findings concerning direct involvement of triggering of Thy-1 as well as deposition of terminal complement complexes in the induction of mesangial cell apoptosis.

Animals↗
PubMedDate not supplied

S-phase fractions and DNA-ploidy of oropharyngeal squamous epithelium carcinomas compared with histologic grade, stage, response to chemotherapy and survival.

DNA-ploidy and the percentage of S-phase fractions in 55 primary oropharyngeal squamous epithelium carcinomas were measured by DNA-Flow Cytometry (FCM). The data were compared with the histologic grade, the stage and the response of the tumours to cytostatic chemotherapy. A significant correlation was found between the histologic grade and the mean percentage of S-phase fractions (p less than 0.01). No correlation could be found between the FCM measurement data and the tumour stage. Carcinomas with an amount from 4.0 to 10.4% S-phase fractions responded to chemotherapy by complete remission, and those with 10.0 to 13.3% S-phase fractions by partial remission. The group of non-responders could be subdivided into two subgroups: non-responders with low amounts of S-phase fractions (1.1-3.9%), and non-responders with very high amounts of S-phase fractions (11.6-16.6%). FCM data, histologic and clinical prognostic factors were summed up to a prognostic score. The number of score points showed a significant correlation to the length of survival in months after diagnosis of the tumour (p less than 0.00001). FCM may be used as an additional diagnostic tool for a better biological characterization of the neoplastic tissue, especially as an aid for grading, prediction of the response to chemotherapy and the length of survival.

Adult↗
PubMedDate not supplied

Differentiation-related p53 protein expression in nondysplastic sinonasal inverted papillomas.

To clarify p53 protein expression in nondysplastic sinonasal inverted papillomas, archived surgical specimens from 19 patients were studied using immunohistochemistry. Staining results were compared between inverted papillomas and adjacent, nonpapillomatous nasal mucosa. Further, immunoreactivity was compared between columnar (respiratory), transitional (cuboidal), and squamous epithelium in inverted papillomas. Positive staining was found in 17 of 19 inverted papillomas (89%). Immunoreactivity involved predominantly basal and parabasal cells and was either comparable or higher in inverted papillomas compared with adjacent mucosa. In 65% of immunoreactive inverted papillomas comparable staining results were seen between columnar (respiratory), transitional (cuboidal), and squamous epithelium. In 35% of p53 protein-positive inverted papillomas, enhanced immunoreactivity was observed in transitional (cuboidal) and squamous epithelium compared with columnar (respiratory) epithelium. Within these cases, immunoreactivity was either comparable or higher in squamous compared with transitional (cuboidal) epithelium. Conclusively, the expression of p53 protein is present in 89% of nondysplastic sinonasal inverted papillomas and also involves the adjacent, nonpapillomatous nasal mucosa. A tendency toward increasing p53 protein expression from nonpapillomatous nasal mucosa to inverted papilloma as well as along the metaplastic process from columnar (respiratory) to transitional (cuboidal) and finally squamous epithelium within inverted papillomas can be postulated.

Adult↗
PubMedDate not supplied

A simple fluorescent technique for the location of tumour cells in frozen sections of the head and neck region.

Tumour cells possess cell surface proteases referred to as guanidinobenzoatase (GB) which are closely similar to plasminogen activator. Previous studies have demonstrated different isoenzymic forms of GB on tumour cells and normal cells which can be recognised by cytoplasmic protein inhibitors extracted from frozen sections of appropriate tissues. We now show that normal human serum possesses inhibitors which selectively recognise the isoenzymic forms of GB associated with normal cell surfaces but do not recognise the GB on tumour cell surfaces in frozen sections of tissue obtained from the head and neck regions.

Aminacrine↗
PubMedDate not supplied

Studies on the interaction and exchange of inhibitors and proteases on the surface of tumour cells in frozen sections.

We have used frozen sections of squamous cell carcinoma as a convenient source of a cell surface protease associated with tumour cells. This protease has been referred to as guanidinobenzoatase (GB) and is now known to be functionally identical to tissue plasminogen activator (t-PA). The use of a fluorescent competitive inhibitor of GB enabled the enzymic status of GB to be determined, i.e. was the enzyme active, latent or removed from our test system. The cell surface GB was then demonstrated to interact with extractable cytoplasmic inhibitors obtained from these sections. We then used a protected form of the GB in the absence of these internal inhibitors; such sections were used to transfer the GB to fibrin fibrils, thus exposing the presumptive receptor on the tumour cell surfaces. Texas red labelled t-PA was then shown to bind to the tumour cells in these pretreated sections from which the GB had previously been removed. We believe that the surface of tumour cells can be used to study the interaction of the naturally occurring inhibitors with GB and also that the cell surface receptors for GB can be used to study the binding of t-PA to cell surfaces.

Aminacrine↗
PubMedDate not supplied

[Combined masseter and buccal mucosa transposition flap. Primary reconstruction of posterior oral cavity].

A method for the primary reconstruction of the posterior oral cavity following T2 and small T3 tumor surgery is described. The combination of a masseter flap with a cranially pedicled intraoral buccal transposition flap results in a double layer for the repair of defects. Because of its simplicity and hence a shorter operation time, this functionally satisfactory reconstructive procedure should be used particularly for high-risk patients.

Aged↗
PubMedDate not supplied

Evidence for the functional similarity between tumour cell surface guanidinobenzoatase and tissue type plasminogen activator.

Tumour cells possess a cell surface protease referred to as guanidinobenzoatase (GB). The active centre of GB binds the fluorescent probe 9-amino acridine (9-AA) and this binding enables cells possessing active GB to be located by fluorescent microscopy. GB binding of 9-AA was inhibited by prior treatment of sections of tumour tissue with a specific polyclonal antibody recognising the tumour associated protease tissue plasminogen activator (t-PA). GB binding of 9-AA was also inhibited by prior treatment of sections of tumour tissues with PAI-I, a protein inhibitor of plasminogen activatory. We conclude from these studies and kinetic analyses that GB and t-PA are very similar both in structure and function.

Aminacrine↗
PubMedDate not supplied

[Use of low-molecular fluorescent dyes for localizing tumor cells].

A novel fluorescence microscopic technique, based on the application of low-molecular fluorescent dyes, was used to study the expression of the enzyme guanidinobenzoatase in malignant tumors of the head and neck area. Frozen sections have shown that moderately and highly differentiated squamous cell carcinomas express this enzyme, particularly in the area of tumor invasion. The protease is capable of breaking down fibronectin, an important component of the extracellular matrix. In less differentiated squamous cell carcinomas as well as malignant melanomas almost all tumor cells exhibited guanidinobenzoatase activity. The fluorescence microscopic technique presented here provides a fast and easy method for the localization of tumor cells. At the same time it provides a better understanding of the biological control of a tumor-associated protease, thus furnishing important new information on the invasion behavior of malignant tumors.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Evidence for cells possessing t-PA like activity in smears obtained from patients with oral squamous cell carcinoma.

Squamous cell carcinoma cells possess a cell surface protease referred to as guanidinobenzoatase (GB) which is very similar to the single chain form of tissue type plasminogen activator. This enzyme binds fluorescent probes at its active center and cells possessing GB can be distinguished from those that lack this enzyme by fluorescent microscopic techniques. Normal squamous epithelial cells shed from the surface of the oral cavity lack GB and do not exhibit cell surface fluorescence when pretreated with such fluorescent probes. We have used this knowledge to design a simple technique for the rapid location of squamous cell carcinoma cells in oral smears; our results are presented in the form of colour prints in which the tumour cells can be easily distinguished from other cells by their fluorescence.

Carboxylic Ester Hydrolases↗
PubMedDate not supplied

A rapid technique for the fluorescent location of pleomorphic adenoma cells in frozen sections of human salivary glands.

Both acinar cells and pleomorphic adenoma cells possess a cell surface protease, guanidinobenzoatase (GB) which can be located with a fluorescent probe for the active centre of this enzyme. We have developed a rapid, cheap, fluorescent technique for the differential location of pleomorphic adenoma cells and acinar cells in frozen sections of salivary glands. The fluorescence of other cells (which also possess GB) is selectively quenched, such that only the acinar and pleomorphic adenoma cells are visualised by fluorescent microscopy.

Adenoma, Pleomorphic↗
PubMedDate not supplied

Density-dependent growth inhibiting interactions between 3T3 and SV40-3T3 cells in mixed cultures.

3T3 cells are shown to reduce SV40-3T3 cell population growth in a denisty-dependent manner in co-cultures of 3T3 and SV40-3T3 cells. The development of this inhibitory activity roughly parallels the development of density-dependent inhibition of growth in homogeneous 3T3 control cultures. The extent of reduction of SV40-3T3 growth can be manipulated by pretreatment of 3T3 cells with a high serum concentration. SV40-3T3 growth rates are reduced by factors between 10 and 20 under optimum inhibitory conditions as compared to SV40-3T3 growth in control cultures.

Animals↗
PubMedDate not supplied

Density-dependent growth adaptation kinetics in 3T3 cell populations following sudden [Ca2+] and temperature changes. A comparison with SV40-3T3 cells.

Lowered extracellular [Ca2+] cause low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2%]. Under otherwise constant conditions the extracellular [Ca2+] determines a stable stationary cell density, which can be reached by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 degrees C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell populations at 35 degrees C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 degrees C than at 35 degrees C, leading to lower stationary cell densities at 39 degrees C than at 35 degrees C. A temperature change from 39 degrees C to 35 degrees C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place.

Animals↗
PubMedDate not supplied

Targeting adriamycin to tumour cells by means of an affinity ligand; a model system for drug delivery.

Actively migrating tumour cells possess the proteolytic enzyme guanidinobenzoatase (GB) in an uninhibited form. This enzyme has been used as a target for the delivery of adriamycin to invasive tumour cells in frozen sections. An adriamycin-agmatine complex has been prepared which act as a competitive inhibitor of GB. Competition experiments have demonstrated that the adriamycin-agmatine complex competes with 9-aminoacridine for the active centre of GB associated with invasive tumour cells, located in the lymph nodes and in squamous cell carcinoma of the oral cavity. The technique described should be generally applicable to the targeting of drugs to cells.

Agmatine↗