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Biomedical subjects

A Franz

Publications and source records attributed to A Franz.

At least 73 records · Page 4Linked to original sources
PubMed1993

Staphylococcal enterotoxin B up-regulates interleukin-2 receptor beta chain expression on tonsillar B cells.

The superantigen staphylococcal enterotoxin B (SEB) selectively up-regulates the interleukin-2 receptor (IL-2R) beta chain (p70) without up-regulating the IL-2R alpha chain (CD25) on a human tonsillar B cell population depleted of T cells. This action of SEB, probably mediated by binding to major histocompatibility complex class II, renders B cells sensitive to T cell-derived IL-2 and is sufficient for induction of vigorous DNA synthesis with low concentrations of IL-2. This explains one of the mechanisms by which bacterial superantigens activate large numbers of B cells and may reflect a similar mechanism operative in cognate helper T cell/B cell interactions.

Adolescent↗
PubMed1993

Influence of medium components and metabolic inhibitors on citric acid production by Penicillium simplicissimum.

Penicillium simplicissimum excreted more than 100 mmol citric acid l-1 [2.9 mmol (g dry wt)-1; 9 d] if an industrial filter dust (> 50% ZnO) providing a high extracellular buffering capacity was present in the medium. A similar specific [2 mmol (g dry wt)-1], but lower absolute (26 mmol l-1), citric acid excretion occurred in the absence of an extracellular buffer and if amino acids or urea were used as nitrogen source. P. simplicissimum excreted no citric acid under conditions where Aspergillus niger produces citric acid (deficiency of trace elements, low pH and reduced biomass formation). Citric acid excretion by P. simplicissimum always paralleled biomass formation and occurred in a pH range between 4 and 7. This indicated that different imbalances of metabolism were responsible for citric acid excretion in A. niger and P. simplicissimum. However, provided a high extracellular buffering capacity was present, the response of the Penicillium system to different carbon and nitrogen sources was similar to the Aspergillus system. In contrast, the metals iron and copper had virtually no effect on citric acid excretion compared with A. niger. Estimation of intracellular citric acid, as well as the effects of the uncoupler 2,4-dinitrophenol, and the H(+)-ATPase inhibitor sodium orthovanadate, led to the conclusion that the buffer-stimulated citric acid efflux was dependent on metabolic energy and an energized plasma membrane, respectively. Despite similarities to the Aspergillus system, a different mechanism for buffer-stimulated citric acid excretion by P. simplicissimum seems probable.

Antimetabolites↗
PubMed1992

Effect of 12,13-phorbol dibutyrate and ionomycin on defective B cells in common variable immunodeficiency.

Secretion of IgM and IgG in vitro by B cells from patients with common variable immunodeficiency (CVI) has been used to classify the disease into three groups. On stimulation with anti-IgM and IL-2, group A patients' cells fail to secrete IgM or IgG, group B patients' cells secrete no IgG and significantly lower levels of IgM than normal cells, and group C patients' cells produce normal levels of both isotypes. Direct activation of protein kinase C using 12,13-phorbol dibutyrate and ionomycin followed by IL-2 or IL-4 has been reported to induce immunoglobulin secretion by normal human B cells. We therefore attempted to induce B cells from group A and group B CVI patients to secrete IgM and IgG after direct activation of protein kinase C together with IL-2 or IL-4. The data show that the failure of secretion of immunoglobulin by B cells from CVI patients could not be reversed using this approach. This finding suggests that the activation channel involving protein kinase C in B cells from CVI patients is not involved in the defect in cell differentiation.

B-Lymphocytes↗
PubMed1991

Barium carbonate intoxication.

A 22-year-old man attempted to commit suicide by swallowing an unknown amount of barium carbonate dissolved in hydrochloric acid. Shortly after ingestion, he developed crampy abdominal pain and generalized muscle weakness. About 2 h later, respiratory failure ensued necessitating orotracheal intubation and mechanical ventilation. Concomitantly, life-threatening arrhythmias including ventricular fibrillation occurred, and he had to be resuscitated for 45 min. After correction of severe hypokalemia (serum potassium 1.5 mmol/l), cardiac rhythm stabilized. In an attempt to accelerate removal of barium from the circulation hemodialysis was begun. During hemodialysis muscle strength returned. Pharmacokinetic analysis of serum barium levels suggest that hemodialysis shortened the serum half-life of barium. Subsequently, the patient made a complete and uneventful recovery. Our case demonstrates that severe barium poisoning can be survived provided that early aggressive therapeutic measures are undertaken. Hemodialysis seems to be efficacious in the therapy of barium intoxication.

Adult↗
PubMed1991

Leaching with Penicillium simplicissimum: Influence of Metals and Buffers on Proton Extrusion and Citric Acid Production.

In the presence of insoluble metal oxides (industrial filter dust, zinc oxide, synthetic mixture of metal oxides), Penicillium simplicissimum developed the ability to excrete considerable amounts of citric acid (>100 mM). Parallel with the increase of citric acid concentration in the culture broth, zinc was solubilized from zinc oxide. The adsorption of filter dust onto the mycelium (the pellets formed were less than 1 mm in diameter) was required for not only the citric acid excretion but also the leaching of zinc. When the filter dust was replaced with a synthetic mixture of metal oxides or with zinc oxide in combination with trace elements, levels of adsorption and citric acid production were observed to be similar to those in experiments where industrial filter dust was used. The two most important properties of the filter dust were its heavy-metal content and its buffering capacity. These properties were simulated by adding heavy metals in soluble form (as chlorides, sulfates, or nitrates) or soluble buffers to the medium. Both heavy metals and buffers were not able to induce a citric acid efflux. As with citric acid production by Aspergillus niger, the addition of manganese lowered citric acid excretion (by 40% with metal oxide-induced citric acid efflux and by 100% with urea-induced citric acid efflux). Copper antagonized the effect of manganese. The mechanism for the bulk of citric acid excretion by P. simplicissimum, however, seemed to be different from that described for citric acid accumulation by A. niger. Because of the inefficiency of metals in solubilized form and of soluble buffers to induce a strong citric acid efflux, adsorption of an insoluble metal compound (zinc oxide) turned out to be essential. Surface phenomena possibly involving the plasma membrane H-ATPase are thought to participate in the induction of citric acid excretion by P. simplicissimum in the presence of industrial filter dust.

Journal Article↗
PubMed1991

Interleukin-2-induced DNA synthesis and immunoglobulin secretion by resting human tonsillar B cells: effects of protein kinase C activation.

Responses to interleukin-2 (IL-2) of high-density human tonsillar B lymphocytes were examined in 20 microliters hanging drop microcultures. DNA synthesis and secretion of IgM and IgG were induced by IL-2 alone. Activation of calcium-dependent protein kinase C (PKC) with phorbol 12,13-dibutyrate and ionomycin increased IL-2 driven DNA synthesis yet reduced IL-2 driven secretion of IgM and IgG. Forskolin, which increases cAMP, had no effect on the responses to IL-2. Intrinsic IL-6 played no role in IL-2-induced DNA synthesis but was partially responsible for the secretion of immunoglobulin. These data show that pre-activation of the high-density human tonsillar B lymphocyte is not a prerequisite for IL-2-driven responses. They also show an asymmetry between the growth and differentiation induced by IL-2. This is reflected by opposite modulation on activation of PKC and by the role of the autocrine factor, IL-6.

B-Lymphocytes↗
PubMed1990

Disseminated tuberculosis after renal transplantation. A report of two cases.

Disseminated mycobacterial infections occurred in two female renal graft recipients late after transplantation. In the first patient, initially presenting with fever, diagnosis was made at autopsy. Temporary defervescence following antibiotic therapy with ofloxacin possibly contributed to the fatal diagnostic delay. In the second case, body temperature was normal throughout the protracted course of the patient's illness. Her presenting symptom was rapidly increasing ascites, attributed initially to chronic liver disease. These cases demonstrate that tuberculosis remains a serious complication after renal transplantation, in particular due to its sometimes atypical clinical manifestations. Response to antibacterial therapy has to be critically evaluated in order to avoid fatal diagnostic delay.

Adult↗
PubMed1990

[Bronchopulmonary diseases in primary immune deficiencies].

Data of 124 patients with primary immunodeficiencies were examined in a retrospective study in respect of incidence and severity of bronchopulmonary immunodeficiencies. Relapsing pneumonias were seen in 40 patients (32.3%) and bronchiectases in 15 cases (12.1%). Children with severe antibody deficiencies or combined immunodeficiencies were involved particularly often. Avoidance of pulmonary complications is of special prognostic importance with these patients.

Bronchitis↗
PubMed1989

The DiGeorge sequence. II. Immunologic findings in partial and complete forms of the disorder.

We present immunological in vitro data on a group of 16 patients with the DiGeorge sequence (DGS). Detailed tests gave evidence that the decrease in number and function of mature T-cells is closely correlated with phenotypic expression and represents a wide immunological spectrum ranging from normal function to severe combined immunodeficiency with B-cells. Careful immunological testing in DGS may help to plan therapeutic procedures (i.e. thymic factor therapy or bone marrow transplantation), may also have prognostic significance and help to gain insight into mechanisms operative in disturbances of T-cell regulation.

Adenosine Deaminase↗
PubMed1989

[Thoracic peridural anesthesia in childhood].

Local and regional anesthesia, especially peridural anesthesia, is a rarely used method in pediatric anesthesia. That cannot be explained by children's physis, since it shows in general neither a different margin of therapeutic safety nor a different effect/side-effect ratio than in adult. Nevertheless, psychologic alteration of children through operation and anesthesia necessitate simultaneous endotracheal narcosis during peridural anesthesia. The following characteristics of regional anesthesia in children should be regarded: The younger the child the higher is the ratio between extracellular water and body weight. Thus higher doses of local anesthetics in relation to body weight can be applied. The smaller diameters of children's nerves support diffusion of local anesthetics and, therefore, allow the use of lower concentrations. Increased perfusion of tissues and high cardiac output lead to rapid resorption and accelerated increase of anesthetic blood levels. This disadvantage can be avoided by use of lower concentrations of anesthetics. Even an extended sympathetic block during peridural anesthesia hardly causes any negative effect on circulatory parameters. We performed thoracic epidural anesthesia during thoracic and upper abdominal surgery in 40 5-15-year-old children. In many of the patients additional risks had already occurred through atelectasis or lung fibrosis. Before introducing the epidural catheter we always carried out endotracheal anesthesia with relaxation to achieve perfect conditions for the puncture. This puncture was made between Th 6 and 10, mostly between Th 7/8, the patient lying on one side. An extension of analgesia between Th 3 and Th 12 was intended, which, however, could not be controlled because of simultaneous endotracheal anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Severe chronic Epstein-Barr virus infection with natural killer cell defect].

Chronic Epstein-Barr virus infection was confirmed serologically in a 27-year-old man with pneumonia, splenomegaly, pancytopenia, arthritis, neuropathy and psychological changes. Immunological tests revealed a defect in the cytotoxic activity of the natural killer cells. Treatment with high doses of acyclovir intravenously and of antimycotic drugs dramatically and lastingly improved the patient's condition.

Acyclovir↗
PubMed1988

Secretory hydrolases of Entamoeba histolytica.

Cells of Entamoeba histolytica grown over a period of four days contained NADP+-dependent alcohol dehydrogenase exclusively inside the cells. No activity of this enzyme could be found in the growth medium after harvesting the cells. Under the same conditions, acid phosphatase, beta-N-acetylglucosaminidase, esterase, alpha-glucosidase, and different amylases of the parasite were found both inside the cells and in the medium. The activities present in the cell homogenate and in the medium before and after growth of the amoebas were partially separated by gel filtration on Sephadex G150 and G75, respectively. The comparison of the elution diagrams revealed that NADP+-dependent alcohol dehydrogenase, acid phosphatase, esterase, and amylases occurred as multiple forms inside the cells. These activities, as well as beta-N-acetylglucosaminidase and alpha-glucosidase, were released into the extracellular environment to a different degree. The enzymes originating from the parasite were identified and distinguished from those of the ingredients of the growth medium according to their molecular mass and pH optimum. Furthermore, the amoebic origin of the secreted enzymes was shown on the basis of their inhibition by antibodies prepared against the supernatant fraction of the homogenate.

Acetylglucosaminidase↗