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Biomedical subjects

A Mayer

Publications and source records attributed to A Mayer.

287 records · Page 16Linked to original sources
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[Possibilities and limits of automatic detection of pathologic intracranial pressure waves with FFT].

Owing to the existence of "reserve spaces" varying individually in extent and expressed by the term compliance, space-consumption intracranial processes do not raise the intracranial pressure (ICP) primarily. Only when this compliance has been exhausted may ICP rise dramatically and may rapidly reach dangerously high levels. It has been shown in the past that "anticipatory" initiation of ICP-reducing measures--i.e. very early in the development of increasing mean ICP--may greatly benefit patient outcome. To recognize an imminent ICP crisis, the available compliance needs to be known. The classical method for determining this latter is the bolus test, which, however, has the disadvantage of being discontinuous and associated with the risk of infection. Another, less invasive and continuous, option is the recognition of pathological intracranial pressure waves. However, recognition of such patterns requires specialized knowledge, that is not widely available. Since, however, knowledge of the compliance is of general importance for intensive care, the idea of developing a PC-based automated system for the identification of pathological waves was followed up. During the course of our basic research effort, we investigated the suitability of the fast Fourier transformation (FFT) algorithm for this purpose. We were able to show that while the FFT is theoretically useful for the detection of pathological intracranial waves, its shortcomings in terms of its sensitivity to extraneous signals (noise) (of considerable importance for biological data handling) and errors in correctly estimating the amplitudes of pathological waves (of great importance for clinical evaluation) make FFT appear less than optimally suitable for this purpose.

Fourier Analysis↗
PubMedDate not supplied

Changes in leptin, insulin and body composition in obese children during a weight reduction program.

BACKGROUND: Girls have higher leptin concentrations than boys at all stages of biological development and this is also seen in the state of obesity. Little is known about whether gender and biological development of obese children influence changes in leptin associated with a short-term weight reduction program. OBJECTIVE: To study whether leptin concentration, body composition and insulin levels in obese children were influenced by a 3-week intervention program including diet and sports. STUDY DESIGN: Sixty-two obese children (32 boys and 30 girls) were examined before and after the intervention program. Body composition was measured by bioelectrical impedance and BMI-SDS was calculated. Serum leptin and serum insulin were determined by RIA. RESULTS: Girls had higher leptin levels than boys, before and after the weight reduction program. Body mass, fat mass (FM), leptin and insulin were decreased after the intervention in both sexes. We found a greater change in serum leptin in girls but the change in FM was of greater magnitude in boys. However, percentage changes in leptin were not significantly different between the sexes. Before the intervention, leptin concentrations were correlated with %FM, FM and moderately with BMI-SDS in all children. Only in pubertal boys did correlation of leptin with %FM increase after the intervention (from r=0.57 to r=0.75, p<0.01). Changes in leptin were found to be associated with initial leptin values in boys (r=0.95, p<0.01) and in girls (r=0.93, p<0.01), independent of Tanner stages. CONCLUSION: Serum leptin levels were positively correlated with adiposity in obese children and a diet and sports intervention program decreased serum leptin, insulin and body fat in all children. Changes in leptin were best described by the initial leptin concentration. The increase in correlation of leptin with %FM in obese pubertal boys after the intervention could have its underlying mechanism in an increased sensitivity to leptin and anabolic hormones.

Adolescent↗
PubMedDate not supplied

Targeting head and neck cancer by GM-CSF-mediated gene therapy in vitro.

BACKGROUND: The prognosis for patients with squamous cell carcinoma of the head and neck (SCCHN) has remained poor during the last decades, emphasizing the need for new treatment modalities. Consequently, the objective of our study was to evaluate the feasibility and efficacy of cytokine-mediated gene therapy in SCCHN in vitro. MATERIALS AND METHODS/RESULTS: The SCCHN cell line PCI-1 was transduced by lipofection with a plasmid encoding the human granulocytemacrophage colony-stimulating factor (GM-CSF). Transfection of PCI-1 resulted in the production of significant amounts of GM-CSF as tested by ELISA. Enhanced proliferation of a GM-CSF sensitive cell line, TF-1, after incubation with supernatants of GM-CSF-transduced tumor cells demonstrated the release of biological active GM-CSF from these PCI-1 cells. In addition, GM-CSF-secreting PCI-1 cells enhanced antitumor cytotoxicity of allogeneic peripheral blood mononuclear cells, as tested in 24h-MTT-cytotoxicity assays. CONCLUSIONS: Our data demonstrate the feasibility and efficacy of GM-CSF-mediated stimulation of the antitumor immune response against SCCHN in vitro and may help to define new strategies in the treatment of this malignancy.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

First clinical data of a natural immunomodulator in colorectal cancer.

BACKGROUND/AIMS: MSC (trade-name AVEMAR) is a per os applicable complex of multiple, biologically active molecules obtained from fermented wheat-germ extract. Preclinical studies suggest potent anti-metastatic activity and it has a favorable toxicity profile. It has been aimed in a pilot-scale, phase II clinical study to document whether or not MSC as a support to surgery or plus chemotherapy adds any therapeutic benefit compared to the same combination without MSC in colorectal cancer. METHODOLOGY: From 1998 to June 1999, 18 control patients and 12 consecutive colorectal cancer patients respectively, were enrolled into this study. All patients underwent curative surgery. The control group (18 patients) received no other therapy or adjuvant chemotherapy alone. The MSC group (12 patients) received MSC alone or plus adjuvant chemotherapy. Until now, the median follow-up has been 9 months. RESULTS: Interim data of the study document that in the MSC group no new metastases, neither hepatic nor other, have occurred, so far. On the contrary, several new metastases have developed in the control group. CONCLUSIONS: Orally administered MSC is a potent candidate to be regarded as a supportive therapy to surgery or plus chemotherapy for colorectal cancer patients.

Adjuvants, Immunologic↗
PubMedDate not supplied

TNFalpha contributes to the antitumor activity of a bispecific, trifunctional antibody.

Immunological cancer therapies focus on the activation of immune effector cells yielding a specific antitumor activity. Disseminated tumor cells are regarded as the origin of metastases and consequently their elimination is the central objective of adjuvant immune therapies. The use of bispecific antibodies is an approach that is regarded as promising in order to fight those disseminated tumor cells. Unfortunately, the efficiency of these antibodies is limited by the fact that they usually activate a single class of effector cell, thus not yielding optimal immune response. In addition, tumor cells may down-regulate the antibody's target molecule and escape recognition. We have recently described results with an intact bispecific molecule, BiUII, that represents a new class of intact antibodies. These antibodies, termed "triomab", provide an excellent antitumor activity in vitro, a fact that most probably is attributable to the simultaneous activation of different classes of immune effector cells. We have now investigated this antitumor activity in more detail and demonstrate here that at least a dual mechanism accounts for triomab-mediated killing of tumor cells: besides direct cell-mediated killing, triomab induces the production of TNFalpha in PBMCs at concentrations that induce apoptosis in target cells. This bystander effect may be of special interest for the clinical application of triomab in terms of killing of target antigen-negative tumor cells.

Antibodies, Bispecific↗
PubMedDate not supplied

Myocardial echinococcosis with perforation into the pericardium.

Though rare, cardiac echinococcosis should be included in the differential diagnosis of cardiac tumors, particularly in patients originating from endemic areas or with manifestation of hydatid disease in other organs. Diagnosis and localisation of the cysts is best accomplished with non-invasive methods such as 2-D transthoracic and transesophageal echocardiography, computed tomography and NMR. Excision of the cardiac cyst from the interventricular septum in a 21 year old patient with polyvisceral echinococcosis was performed with cardiopulmonary bypass. Adjunctive medical therapy with mebendazol is being continued for 24 months postoperatively. Twelve months after surgery the patient is asymptomatic without echocardiographic signs of recurrence.

Adult↗
PubMedDate not supplied

[Analysis of hospital mortality in the Croatian Republic using selected indicators].

Mortality trends and distribution in a system of 32 general and teaching hospitals in the Republic of Croatia for the years 1966 through 1989, separately for 1986/1987, were evaluated as a possible informational support to the national policies regarding developing of health care system. By means of 13 elaborated and/or selected indicators, using hospital health statistics as a data base, we measured the changes in the dynamics, structure and level of death at institutions, individual medical departments and among patients. Hospitals mortality statistics was found to offer a good informational orientation for monitoring realization of the hospital's restructuring activities envisaged under the Aim 29 of the Croatian strategy Health for All by the Year 2000 as well as for planning technical surveillance and streamlining the special statistical studies on inpatient health care. It can also provide a solid base for the evaluation of the quality of inpatient medical care, if the diagnosis of causes of death is improved, methodology for sentinel-health-events adopted, commissions for the evaluation of inpatient health care organized, medical registration units established and the National Register of Autopsy begun.

Adult↗