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Biomedical subjects

M Bergman

Publications and source records attributed to M Bergman.

At least 37 records · Page 2Linked to original sources
PubMed1999

The effect of drug cost on hypertension treatment decision.

The cost of medical care is constantly increasing. Therefore, ways of saving expenses should be considered. The aim of the present study is to evaluate the possibility than an awareness of the cost of drugs for treatment of hypertension may affect physicians' prescription decisions. A questionnaire containing the clinical data of a young and an elderly imaginary patient with moderate hypertension was given to 30 family physicians and 30 hospital physicians together with a list of appropriate drugs (phase I). This was repeated as phase II except that for this stage the cost of the drugs was brought to the participants' attention. Knowing the cost of the drugs caused a decrease in prescription of the more expensive drugs for the younger patients; of 60% (family physicians) and 87% (hospital physicians). For their elderly patients family physicians preferred the less expensive drugs at both phases. 25% of the hospital doctors changed their preference towards less expensive drugs at phase II. For the younger patient, no correlation was found between the number of years of physicians' practice and the cost of the drugs chosen. For the elderly patient, physicians from both groups preferred less expensive drugs at phase II without any relation to their years of practice. The results of this study indicate that a knowledge of the price of the drugs may affect physicians' prescription decisions, a fact that may result in considerable saving by health providing organizations.

Adult↗
PubMed1999

Adenosine stimulates ANP expression in cultured ventricular cardiomyocytes.

Adenosine protects the ischemic myocardium by coronary vasodilation and the depression of heart rate and contractility, improving myocardial energy balance. Adenosine effects on the myocardium are mediated predominantly by the type A1 receptors. Atrial natriuretic peptide (ANP), a vasodilator and regulator of blood volume, is secreted from either atrial or ventricular myocytes in response to cellular distention. In vivo, adenosine infusion has been shown to induce a rapid increase in plasma ANP, independent of blood pressure. We examined the possibility that adenosine enhances ANP-gene expression in cardiac myocytes. Administration of adenosine (10 microM) to cultured neonatal rat cardiomyocytes led to a 1.7-fold increase (p = 0.014, n = 9) in the abundance of ANP messenger RNA (mRNA) within 30 min, as measured by Northern blot hybridization. No such increase was obtained when adenosine was coadministered with 8-cyclopentyl-1,3dipropylxanthine (CPX, 10 microM), an adenosine A1-receptor antagonist. Our results point at adenosine as regulator of ANP mRNA level in cardiac myocytes.

Adenosine↗
PubMed1999

Lipopolysaccharide-induced oxidative stress in the liver: comparison between rat and rabbit.

In the present study the effect of LPS on biochemical systems involved in radical formation and scavenging processes in tissues from rabbit (LPS-sensitive) and rat (LPS-resistant) was investigated. The results obtained show a significant enhancement in the endogenous antioxidative enzyme system in rats as a result of LPS injection. In rats, 24 h after LPS injection, glutathione peroxidase (G-POX) and superoxide dismutase (SOD) activities were increased by 60% and 120%, respectively, compared to the control. However, in rabbits the increase in these activities was relatively mild. Moreover, NADPH-oxidase activity, which produces superoxide radical, was increased about twofold in rabbit, 15 h following LPS injection. In rats, injection of LPS did not result in any significant changes in the activity of this enzyme. In rats, a decrease in malonaldehyde (MDA) levels appeared after injection of LPS, while in contradistinction, the peroxidative levels of lipids in the rabbit's liver were increased about 3-fold. Injection of D-galactosamine (Gal-N) in combination with LPS significantly increased the sensitivity of rats to LPS characterized by a significant increase in NADPH-oxidase activity. This study indicates that one possible mechanism (among others) that may explain the relative sensitivity of rabbits compared to rat, may be related to the increase in the production of reactive oxygen substances (ROS) which is not accompanied by a concomitant increase of the protective antioxidative enzymes. Furthermore, the relative resistance of the rat was found to be related to an increase in the activity of the protective antioxidative systems following administration of LPS.

Animals↗
PubMed1999

Effect of training on the phagocytic capacity of peritoneal macrophages from rats exposed to swim stress.

Since strenuous effort may affect the immune system, a study was designed to examine the impact of the progressive training of rats exposed to swim stress. Rats (trained swimmers) were forced to swim daily in a water bath for progressively longer periods. At the end of the study, which continued for a total of 6 weeks, the superoxide anion generation and phagocytic capacity of peritoneal macrophages, the mitogen response of splenic cells (splenocytes) and the serum corticosterone level were examined. The results, compared to those of animals taken in and out of their cages (nonswimmers), showed an increase in superoxide anion generation, as well as a decrease in both the percentage of phagocytosing cells and the number of particles internalized by each individual cell. In trained swimmers, the mitogen response to phytohemagglutinin and concanavalin A (Con A), as well as the corticosterone level, did not change significantly from those of nonswimmers. A third group of animals were forced to swim once only for 30 min, until the appearance of signs of marked fatigue (acute swimmers). Their peritoneal macrophages showed an increased superoxide anion generation and a significantly decreased response to Con A compared to those of the nonswimmers. The serum corticosterone level in acute swimmers was found to be increased compared to that of an additional group of animals kept at complete rest. The findings indicate that the progressive training of rats exposed to swim stress does not prevent alterations in certain immune responses, a fact that should be considered by intensive exercisers.

Animals↗
PubMed1999

Docetaxel: standard recommended dose of 100 mg/m(2) is effective but not feasible for some metastatic breast cancer patients heavily pretreated with chemotherapy-A phase II single-center study.

PURPOSE: Patients with metastatic breast cancer, especially those with progression after several prior chemotherapy treatments, need efficient chemotherapy. This study investigates the efficacy and toxicity of docetaxel in metastatic breast cancer patients with previous chemotherapy for metastatic disease. PATIENTS AND METHODS: Thirty-one women (median age, 52 years; range, 40 to 65 years) treated for metastatic breast cancer with docetaxel were included. Eleven patients had one metastatic site, 10 patients had two, and 10 patients had three or more. The planned dose of docetaxel per course was the standard treatment of 100 mg/m(2) (or 75 mg/m(2) if liver enzyme levels were abnormal) every 3 weeks, given for six or eight cycles. RESULTS: The overall response rate was 48% (three complete responses [CR] and 11 partial responses [PR] ), and the median duration of response was 7 months (range, 2 to 16 months). Twenty patients (65%) experienced fatigue, and 27 patients (87%) had alopecia. Fifteen cases (48%) of grade 4 leukopenia were observed. Edema with a weight gain of 2 to 15 kg was seen in 12 patients (39%), and mucositis occurred in 20 patients (65%). Twenty-three patients (74%) interrupted treatment before reaching the planned number of courses, nine patients owing to progression of cancer and 14 owing to toxicity. Dose reduction was required in 18 (61%) of the patients. Only two patients were able to receive the planned eight courses without dose reduction. CONCLUSION: Docetaxel is highly active in metastatic breast cancer, even as a third-line treatment, and can be considered as an efficient standard option in second-line treatment. The standard recommended dose level of 100 mg/m(2) is not feasible in heavily pretreated patients; therefore, for such patients, an initial dose level not exceeding 75 mg/m(2) is recommended.

Adult↗
PubMed1999

The Decim system for the production of dental restorations.

The general background to the development of CAD/CAM is presented in short. Specific problems when using this technique for the manufacturing of dental restorations are emphasized, and then the reverse engineering and CAD/CAM process that have been implemented in the Decim (Dentronic AB, Skellefteå, Sweden) system are presented. The system is organized in the following way: 1. The measurement process is encapsulated in a product called Decim Reader. 2. The design functionality is provided by software running on a conventional personal computer. This unit is called Decim Designer. 3. The CAM calculation is done by a dedicated personal computer, the Decim Calculator, that does not require any user interaction. 4. The actual manufacturing of the restorations is performed in the Decim Producer that works with a grinding technique. These components communicate via a local computer network or, when a distributed solution is desired, via internet. The Decim System is presently used for the production of dental ceramic restorations, and it is the only system which can be used for manufacturing inlays of yttria-stabilized zirconia. This ceramic material is CE-approved under the brand name Denzir (Dentronic AB, Skellefteå, Sweden). Due to its favorable mechanical properties, it may be an alternative to dental amalgam, and is therefore of topical interest in dentistry. The use of computer-based techniques for manufacturing dental restorations is briefly outlined and commented on.

Ceramics↗
PubMed1998

Effect of sodium thiopentone anesthesia on the phagocytic activity of rat peritoneal macrophages.

To elucidate the effect of sodium thiopentone anesthesia on the function of phagocytic cells, albino rats were anesthetized with 60 mg/kg. of sodium thiopentone. After 90 min., peritoneal macrophages were harvested and their capacity for superoxide anion generation was detected. Following anesthesia for 90 min. latex particles were injected intraperitoneally, and after additional 30 min. the macrophages were derived, embedded in agar and the number of cells engaged in phagocytosis, as well as the number of latex particles engulfed by each individual cell were counted in semi-thick sections. Macrophages of anesthetized animals showed a statistically significant decrease of both superoxide anion generation and mean number of phagocytic cells, and engulfed fewer particles than those of the controls. Similar results were obtained following incubation of the cells with sodium thiopentone in vitro. The serum corticosterone level in anesthetized rats was significantly higher than that of the control animals. The results indicate that impaired phagocytosis following anesthesia induced by sodium thiopentone, in addition to alterations of the immune system caused by surgical trauma, may be one of the reasons for increased susceptibility to infections of surgical patients during the postoperative period.

Anesthesia↗
PubMed1998

Effect of three days starvation on the phagocytic activity of rat peritoneal macrophages.

To examine the effect of starvation on the phagocytic activity of rat peritoneal macrophages, 8 animals were kept for 3 days on water supply only. The cells showed an increased capacity for superoxide anion production and a marked decrease in their ability to engulf latex particles. The corticosterone level of the fasting animals was markedly increased, an observation suggesting that the alteration of macrophage function could be hormonally mediated. The findings in the present study indicate that the decreased phagocytic capacity of peritoneal macrophages following starvation may be one of the factors responsible for the increased susceptibility to infections in malnourished individuals.

Animals↗
PubMed1997

Identification of csk tyrosine phosphorylation sites and a tyrosine residue important for kinase domain structure.

The lack of a conserved tyrosine autophosphorylation site is a unique feature of the C-terminal Src-kinase, Csk, although this protein tyrosine kinase can be autophosphorylated on tyrosine residues in vitro and in bacteria. Here we show that human Csk is tyrosine phosphorylated in HeLa cells treated with sodium pervanadate. Phosphorylation in vivo occurs mainly at Tyr-184 and in vitro mainly at Tyr-304. A Y304F mutation strongly decreased Csk phosphorylation in vitro, and a Y184F mutation abolished tyrosine phosphorylation in vivo. A catalytically inactive form of Csk was also phosphorylated on Tyr-184 in vivo, suggesting that this is not a site of autophosphorylation. The kinase activity of the Y184F protein was not changed, while the Y304F protein showed one-third of wild-type activity. Three-dimensional modelling of the Csk kinase domain indicated that the Y304F mutation abolishes one of two conserved hydrogen bonds between the upper and the lower lobes in the open conformation of the kinase domain. Phosphopeptide binding studies suggested that phosphorylation of Tyr-184 creates a binding site for low-molecular-mass proteins. Cellular Csk was associated with several phosphoproteins, some of which were interacting with the Csk SH2 domain. Taken together these results indicate that Csk can be phosphorylated in vivo at Tyr-184 by an as yet unknown tyrosine kinase, and that autophosphorylation of Tyr-304 occurs only at abnormally high Csk concentrations in vitro. Furthermore, Tyr-304 is required for the maintenance of the structure of the Csk kinase domain.

CSK Tyrosine-Protein Kinase↗
PubMed1997

Multisensory speech perception of young children with profound hearing loss.

The contribution of a two-channel vibrotactile aid (Trill VTA 2/3, AVR Communications LTD) to the audiovisual perception of speech was evaluated in four young children with profound hearing loss using words and speech pattern contrasts. An intensive, hierarchical, and systematic training program was provided. The results show that the addition of the tactile (T) modality to the auditory and visual (A+V) modalities enhanced speech perception performance significantly on all tests. Specifically, at the end of the training sessions, the tactile supplementation increased word recognition scores in a 44-word, closed-set task by 12 percentage points; detection of consonant in final position by 50 percentage points; detection of sibilant in final position by 30 percentage points; and detection of voicing in final position by 25 percentage points. Significant learning over time was evident for all test materials, in all modalities. As expected, fastest learning (i.e., smallest time constants) was found for the AVT condition. The results of this study provide further evidence that sensory information provided by the tactile modality can enhance speech perception in young children.

Child, Preschool↗
PubMed1997

Do drug costs affect physicians' prescription decisions?

OBJECTIVE: To study the impact of the cost of pharmaceuticals on physicians' decisions about drug prescription. DESIGN: A simulation protocol for the treatment of two patients, one with mild and the other with a severe form of urinary tract infection (UTI), was designed. Thirty family physicians in outpatient clinics and 30 physicians in the internal medicine wards of a Community Hospital participated in the project. They had to prescribe treatment for the patients twice: at phase I, when the drug cost was unknown, and at phase II, after 2 months, when the price of the drugs was brought to their attention. The physicians selected the medication from a list of drugs commonly used for the treatment of UTIs. RESULTS: Analysis of the findings indicates that an awareness of drug costs affects prescription decisions among physicians in hospital wards, whereas family physicians showed a preference for less expensive drugs even before they were informed about drug costs. An extrapolation of the results shows that knowledge about the cost of the drugs usually administered for treatment of UTI, could save at least IS 112,883 ($34,207) a month to Kupat Holim Klalit (KHK) the health insurance institution to which the outpatient clinics and the hospital belong. CONCLUSIONS: When economic aspects of healthcare are considered, information on drug costs may be an important factor in physicians' decision-making processes and for saving pharmaceutical expenses.

Anti-Bacterial Agents↗
PubMed1997

Comparison of induced and independent major depressive disorders in 2,945 alcoholics.

OBJECTIVE: Depressive episodes among alcohol-dependent men and women are heterogeneous in causation and clinical course. This study tested three hypotheses regarding the rates and clinical characteristics of two potential subtypes of these affective states: those that appear to be substance-induced mood disorders and those that are independent major depressive episodes. METHOD: Semistructured, detailed interviews were administered to 2,945 alcohol-dependent subjects as part of the Collaborative Study on the Genetics of Alcoholism. With the use of a time line method for determining the type of mood disorder among probands, relatives, and comparison subjects, individuals with histories of the two types of mood disorders were compared. RESULTS: Major depressive episodes with an onset before the development of alcohol dependence or during a subsequent long abstinence period (i.e., independent depressions) were observed in 15.2% of the alcoholics, while 26.4% reported at least one substance-induced depressive episode. According to a logistic regression analysis, the subjects with independent (as compared to substance-induced) major depressive episodes were more likely to be married, Caucasian, and female, to have had experience with fewer drugs and less treatment for alcoholism, to have attempted suicide, and, on the basis of personal interviews with family members, to have a close relative with a major mood disorder. CONCLUSIONS: These results support the contention that it is possible to differentiate between what appear to be substance-induced and independent depressive episodes in alcoholics. Such differentiation might be important for establishing prognosis and optimal treatment.

Adult↗
PubMed1997

Connections between polarization curves and log(a[i]/a[ref])-pe diagram.

When reading papers concerning studies of corrosion of dental amalgam and its phases by means of polarization curves, one often finds it difficult to understand the reasons for the chemical reactions proposed from the form of the polarization curve. Thermodynamic data represented in the form of log(a[i]/a[ref])-pe diagrams, i.e., the logarithm of the activity of a metal or an alloy with reference to the activity of the corresponding metal ion, as a function of pe (a recalculated form of the potential), make it possible for one to determine which chemical reactions can occur on the specimen surface or in the solution within the potential difference used in the polarization experiment and to decide which of these reactions is the most probable. The hypothesis examined in this study is that a log(a[i]/a[ref])-pe diagram can be used in the interpretation of polarization curves. Potentiodynamic polarization curves and log(a[i]/a[ref])-pe diagrams were compared for the corrosion of Ag, Hg, and gamma 1 with and without Sn. It was found that there was a connection between the polarization curves and the log(a[i]/a[ref])-pe diagrams. From the composition of the specimens and the solution and by means of thermodynamic data, pe values for solid corrosion products and relative concentrations of soluble complexes at these pe values were obtained independently of the polarization curves. A much more reliable value for the nobility of metals and alloys was attained by use of the log(a[i]/a[ref])-pe diagrams than by use of the potential of the starting point of the polarization curves. It was found that pe corresponding to the potential of the starting point of the polarization curves in de-aerated synthetic saliva was obtained about two pe units before pe of the most insoluble solid compound formed on the specimen surface or in the solution.

Corrosion↗