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Biomedical subjects

I Florin

Publications and source records attributed to I Florin.

At least 19 recordsLinked to original sources
PubMed1992

Childhood asthma: paternal critical attitude and father-child interaction.

The study investigated paternal critical attitude (CA) and negative father-child communication in families with an asthmatic child and in controls. Twenty-seven children with bronchial asthma (6-13 yr) and 23 healthy children with their fathers participated in the project. Fathers were asked to describe their child (Five Minute Speech Sample; FMSS). Additionally, father and child discussed a mutual problem (Problem Discussion; PD). Tape recordings were taken. Critical attitude (CA) was assessed from the fathers' responses during the FMSS. Negative verbal behavior during PD was coded for father and child. During the FMSS, significantly more fathers of the asthmatic children than of the controls showed CA. During the PD, fathers of the asthmatic children made significantly more critical remarks than their controls. Significantly more long sequences of negative verbal communication occurred in father-child dyads with an asthmatic child than in the control dyads. No significant relationship was found between either the fathers' attitudes or amount of negative verbal communication and the children's severity of asthma, compliance, or IgE status.

Adolescent↗
PubMed1992

Production of enterotoxin and cytotoxin in Campylobacter jejuni strains isolated in Costa Rica.

The production of toxins by 79 strains of Campylobacter jejuni isolated in Costa Rica from children with campylobacter-induced diarrhoea (44 strains) and from chickens (35 strains) was studied. An enterotoxic effect giving a rounding of mouse adrenocortical tumour (Y1) cells, which could be neutralised with antitoxin against Escherichia coli heat-labile enterotoxin, was detected in supernates from 16 (62%) of 26 strains from children with watery diarrhoea, in 5 (28%) of 18 strains from children with bloody or inflammatory diarrhoea, and in 12 (34%) of the 35 strains from chickens. Cytotoxic effects in human lung fibroblasts (MRC-5), African Green monkey kidney (Vero) cells and human cervical carcinoma (HeLa) cells were observed in none of the 26 strains from children with watery diarrhoea, in 2 (11%) of the 18 strains from children with bloody or inflammatory diarrhoea, and in 6 (17%) of the 35 strains from chickens. The simultaneous production of enterotoxin and cytotoxin was detected in four strains. The cytotoxic effect, which was most prominent in cells freshly seeded at a low density, appeared as a lethal rounding of the cells. Fibroblasts were more sensitive than epithelial cells. The effects of the supernates were inactivated by heating at 100 degrees C for 10 min and decreased after 1 week at 4 degrees C. The production of toxins was lost after storage of the strains for one year at -70 degrees C.

Animals↗
PubMed1992

Expressed emotion in depressed patients and their partners.

This study was designed to assess the expressed emotion (EE) status in the spouses of depressed patients and the patients themselves, to relate the EE status to the severity of depression as measured by the Beck Depression Inventory (BDI), and to compare the prevalence of high EE between the target and control group. Seventeen depressed patients and their spouses, and 20 control couples participated in the study. The Five-Minute Speech Sample was used to assess the EE status. High EE was significantly more common in spouses of depressed patients and the patients themselves than in controls. There was a significant relationship between the EE status of the patients and their spouses. High EE in the patient and in the spouse corresponded significantly with a high BDI score of the patient. These findings underline the importance that in EE research the patients' EE status as well as their present mental health state must also be taken into account.

Adult↗
PubMed1992

[Hospital care versus home nursing: on the quality of life of terminal tumor patients].

The present study investigated quality of life in 41 terminally ill cancer patients. Twenty-one of them received hospital care, 20 home-bound hospice care. These groups were comparable with respect to the patients' physical condition. The following variables were chosen as indicators of quality of life: perceived social support and social distress, coping with illness, perceived positive environmental factors, perceived control over daily activities and caring routines, contentedness with medical care and nursing, physical well-being. Assessment was made by means of a semi-structured interview. The data indicate that the home-bound care was superior with respect to the following variables: perceived positive environmental factors, perceived control over daily activities and caring routines, and contentedness with nursing. No differences between groups were found for any of the other variables.

Adult↗
PubMed1991

ADP-ribosylation in Clostridium difficile toxin-treated cells is not related to cytopathogenicity of toxin B.

ADP-ribosylation of a protein in human fibroblasts treated with partially purified Clostridium difficile toxin B was previously reported. Here we show that the same protein was ADP-ribosylated also in human fibroblasts exposed to supernatant from a C. difficile strain producing neither toxin A nor toxin B. Furthermore, in Chinese hamster ovary and in Vero cells, showing toxin B-induced cytopathogenic effect, the protein was not significantly ADP-ribosylated. The results indicate that the ADP-ribosylation is unrelated to the cytopathogenic effect of toxin B. It appears to be caused by another unidentified factor from C. difficile, and the substrate may correspond to a protein modified endogenously in cells exposed to stressful situations. Cellular actin was not ADP-ribosylated by toxin B.

Adenosine Diphosphate Ribose↗
PubMed1991

Isolation of a fibroblast mutant resistant to Clostridium difficile toxins A and B.

A mutant of Chinese hamster lung fibroblasts (Don cells), resistant against Clostridium difficile toxins A and B, was isolated after mutagenization with ethylmethanesulphonate and a two-step selection with toxin B. The mutant, termed CdtR-Q, was 10(4) times more resistant to toxin B than wild-type cells and cross-resistant to toxin A (10(3) times more resistant). The resistance was overcome by increasing the dose of toxin. The resistance has been stable after cultivation for 40 generations in the absence of toxin. The morphology of the mutant was more epithelial-like than that of the fibroblast parental cells. The plating efficiency was about half that of the wild-type, whereas the growth rate was the same. The mutant was significantly less sensitive than the wild-type to the microfilament-interacting cytochalasins B and D. It was as sensitive as the wild-type to endocytosed toxins (diphtheria, pertussis, ricin), to microtubule-interacting agents (colchicine, gossypol, nocodazole, taxol, vinblastine), and to membrane-damaging toxins with different mechanisms of action, with one exception; the mutant was more highly sensitive to the action of phospholipase C (with broad substrate-specificity) than the wild-type. The results suggest that the mutant has a normal endocytosis, and that the mutation does not affect the microtubuli. The results are consistent with a mutation affecting the microfilaments in the cytoskeleton.

Animals↗
PubMed1990

Microfilament-disrupting Clostridium difficile toxin B causes multinucleation of transformed cells but does not block capping of membrane Ig.

The effects of Clostridium difficile toxin B on some actin-dependent cellular functions were studied. A three-day incubation of intoxicated B-lymphocytes and transformed 3T3 fibroblasts resulted in dose-dependent multinucleation. Using vimentin-negative Daudi cells we showed that this effect of toxin B does not involve vimentin. As DNA and protein syntheses are not impaired in the cells used, the results suggest that toxin B has an effect on the actin-containing contractile ring during mitosis, in a manner similar to that of the microfilament-disrupting agent cytochalasin B. Toxin B is the first bacterial toxin shown to have this effect. It was also found that the capping of surface IgM on B-lymphocytes was not inhibited by toxin B, whereas cytochalasin B did inhibit capping. These results suggest that capping is dependent on a specific membrane-associated actin structure, which is not affected by toxin B.

Actin Cytoskeleton↗
PubMed1989

Maternal criticism, mother-child interaction, and bronchial asthma.

The study investigated maternal critical attitude (CA) and negative mother-child communication in families with an asthmatic child and in controls. Twenty-five children with bronchial asthma (7-13 yr) and 25 healthy children with their mothers participated in the project. Mothers were asked to describe their child (Five Minute Speech Sample; FMSS). Additionally mother and child discussed a mutual problem (Problem Discussion; PD). Videorecordings were taken. CA was assessed from the mothers' responses during FMSS. Negative verbal behavior during PD was coded for mother and child. During FMSS significantly more mothers of the asthmatic children than of the controls showed CA. During PD mothers of the asthmatic children made significantly more critical remarks than their controls. Within the asthmatic group, CA mothers showed significantly more criticisms than those with non-CA. Significantly more long sequences of negative verbal interaction occurred in mother-child-dyads with a CA mother than in those with a non-CA mother.

Adolescent↗
PubMed1989

Dysfunctional cognitions, attributional style, and depression in bulimia.

A group of 44 bulimic women (DSM-III) as well as 38 women with no indication of an eating disorder, comparable with respect to age, weight and height, were studied by means of the Beck Depression Inventory (BDI), the Dysfunctional Attitude Scale (DAS), the Attributional Style Questionnaire (ASQ), and an Eating Disorder Questionnaire (EDQ). Bulimics showed significantly higher BDI, DAS and ASQ (bad events) scores, respectively. In both groups BDI scores were significantly correlated with DAS and ASQ (bad events) results. BDI was highly predictive of severity of bulimia while no significant prediction was obtained from either DAS or ASQ (bad events) scores. The findings provide first evidence that dysfunctional attitudes and depressive attributional style are predominant in bulimic women but at the same time are not necessarily predictive of the severity of the disorder.

Adult↗
PubMed1988

Pressure sensitivity in bulimic women: a contribution to research in body image distortion.

The present study is a first step towards specifying perceptual peculiarities rather than visual ones that may contribute to a distorted body boundary experience in women meeting DSM III criteria for a diagnosis of bulimia. Fourteen bulimic women and 14 women without bulimia but closely matched in age, height and weight participated in the study. Pressure sensitivity was measured by means of the von Frey method under three conditions: (1) at the tip of the right index finger, (2) at the lower abdomen, (3) at the lower abdomen again, but with financial reward promised for high performance. Data confirmed the hypothesis that at both sites pressure sensitivity thresholds would be significantly higher for the bulimic group than for the comparison group. It is possible that deficits in pressure sensitivity are related to overestimation of the width of the respective body parts.

Adult↗
PubMed1988

Distorted body image in bulimic women.

Fifteen bulimic women (DSM III) and 15 women with no indication of an eating disorder, matched pairwise with respect to age, weight and height, were assessed via a distorting video image technique under four conditions. They were asked to: (1) estimate the width of a water bottle, (2) estimate the width of their own body, (3) repeat those estimates under a condition of reward for high accuracy, (4) focus attention on their bodily sensations and indicate how wide their body felt. While groups did not differ in their estimates under condition 1 (water bottle), significant differences were found between groups under conditions 2, 3 and 4 (own body), the percentage of overestimating being highest when subjects were to indicate how wide their body felt. Results suggest that modalities of perception other than visual are strongly involved in the body image distortion of bulimics.

Adult↗
PubMed1987

Calcium and calmodulin in cellular intoxication with Clostridium difficile toxin B.

In cultured human lung fibroblasts treated with Clostridium difficile toxin B, the development of the cytopathogenic effect was inhibited by the proton ionophore monensin but was not affected by some other ionophores. The calcium channel blockers verapamil and LaCl3 protected the cells against intoxication, as did the calmodulin antagonists trifluoperazine, amitriptyline, R 24571, and dansylcadaverine. Since these agents could not prevent intoxication when added after the toxin internalization was completed, we suggest that calmodulin and uptake of extracellular calcium are needed for the internalization but not for the cytosolic action of the toxin.

Bacterial Proteins↗
PubMed1987

Cellular internalisation of Clostridium difficile toxin A.

The cytopathogenic effect of toxin A from Clostridium difficile was studied in cultured human lung fibroblasts. The final effect was dependent on toxin concentration and exposure time. Binding of the toxin to cells occurred at 0 degrees C as well as at 37 degrees C. The latency before appearance of the cytopathogenic effect was dose-dependent with a minimum of 45 min. The appearance of a cytopathogenic effect in toxin-treated cells was prevented by the addition of trypsin, antitoxin, lysosomotropic agents, inhibitors of the energy metabolism, 200 mM KCl, 20 mM benzyl alcohol and by incubation at 18 degrees C. Several inhibitors of lysosomal proteases did not prevent the appearance of the cytopathogenic effect. When the extracellular pH was lowered to 4.5 for 5 min immediately after toxin binding the period of latency was significantly shortened. Likewise, the protective effects of lysosomotropic agents were abolished by lowering the extracellular pH. Chinese hamster ovary cell mutants, defective in acidification of their endosomes, were less sensitive to toxin A than wildtype cells. The results indicate that cellular internalisation of toxin A is necessary for intoxication. Moreover, we postulate that the toxin needs some sort of enzymatic activation which can take place only after exposure of the toxin to a low pH.

Animals↗
PubMed1986

ADP-ribosylation in cultured cells treated with Clostridium difficile toxin B.

In cultured fibroblasts intoxicated with Clostridium difficile toxin B, a radioactive moiety was transferred from [14C-adenosine]NAD, but not from [14C-nicotinamide] NAD, into a cellular protein (MW 90,000). No labeling was detected in toxin-treated cultures not yet showing any toxin-induced cytopathogenic effect, whereas maximal labeling was obtained in cultures with about half of the cells showing a cytopathogenic effect. The radioactivity was removed from the substrate by treatment with snake venom phosphodiesterase. The results suggest that ADP-ribosylation of a cellular protein occurs in toxin B-treated cells and that this reaction may be responsible for development of the cytopathogenic effect.

Adenosine Diphosphate Ribose↗
PubMed1986

Expression of emotion in asthmatic children and their mothers.

The present study assessed how general asthmatic children's deficit in the facial expression of emotion is that we found in previous studies. Furthermore, the emotional behavior of the patients' mothers was explored. Eighteen children with bronchial asthma (ages 7.6 to 12.6), and eighteen control children were subjected to two frustrating achievement situations. They had to solve a difficult puzzle under time pressure by themselves, and with the verbal assistance of their healthy mothers. Facial expressions of emotion and heart rate were recorded from children and mothers. No deficit in emotion expression was observed in the asthmatic group. To the contrary, asthmatic children showed more expressions of anger/aggression and emotion expressions in total during the last phase of the 'child alone' condition. Moreover, in both experimental conditions they showed more unspecified facial movements than control children. Mothers of asthmatic children expressed more happiness than their controls. Heart rate data did not differentiate between target and control groups during any phase of the experiment. These findings counter psychodynamically based assumptions on emotional behavior of asthmatics and their mothers.

Achievement↗
PubMed1986

Lysosomal involvement in cellular intoxication with Clostridium difficile toxin B.

The process of internalisation of Clostridium difficile toxin B into human lung fibroblasts was further studied, with the aim of elucidating the fate of endocytosed toxin. Development of the toxin-induced cytopathogenic effect was reversibly inhibited at 18 degrees C and in the presence of 200 mM KCl or 1-20 mM benzyl alcohol, i.e. at conditions when the fusion between endosomes and lysosomes is prevented. Fibroblasts treated with toxin at 37 degrees C but transferred to 18 degrees C within 10 min were also completely protected, whereas transfer to 18 degrees C later during the latency resulted in only partial protection. KCl was also protective upon addition after the toxin binding step. Inhibitors of lysosomal proteases, such as chymostatin, leupeptin and antipain, prevented the appearance of the cytopathogenic effect, when present during toxin exposure or added after the toxin binding step. Chinese hamster ovary cell mutants, defective in acidification of their endosomes, were resistant to toxin B, whereas wildtype cells were sensitive. The resistance was not overcome by applying a low extracellular pH. The results suggest that exposure to a low pH compartment is necessary but not sufficient for entry of active toxin B to the cytosol. In addition to a low pH, a fusion of toxin-containing endosomes with lysosomes and a further processing of the toxin by lysosomal proteases is required for cellular intoxication.

Animals↗
PubMed1984

Polyphosphate-mediated protection from cellular intoxication with Clostridium difficile toxin B.

The influence of polyphosphorylated compounds on intoxication of human lung fibroblasts with Clostridium difficile toxin B was studied. ATP, as well as other nucleoside di-, tri-, and tetraphosphates, inorganic polyphosphates and polyphosphorylated sugars, caused a dose-dependent (1-5 mM range) delay in the appearance of the cytopathogenic effect. With a longer phosphate chain, the delay was more pronounced, although the cytopathogenic effect always developed finally, reaching the level of the control within 20 h. Toxin preparations contained one fraction of molecules able to bind ATP, besides one non-binding fraction. The protective effect of ATP did not depend on its energy producing ability. Neither was the protective effect due to an inactivation of the toxin per se, or to an interference with binding of the toxin to the cells. ATP was protective even upon addition 10 min after the toxin binding step. In the presence of ATP, the toxin remained accessible to neutralization with antitoxin. In analogy with the P-site on diphtheria toxin, we postulate that C. difficile toxin B contains a polyphosphate-binding site. This site is separate from the receptor-binding site, but involved in the interaction of toxin B with the cell surface shortly after the binding step.

Adenosine Triphosphate↗