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Biomedical subjects

R Gundersen

Publications and source records attributed to R Gundersen.

15 recordsLinked to original sources
PubMed1999

[Pharmacists' and general practitioners' views on parallel import of drugs].

Since 1995, parallel import of drugs to Norway has been allowed under the European Economic Area Agreement. The health authorities have stated that there are no concerns connected with the use of parallel-imported drugs. This study is an interview survey among general practitioners, pharmacy staff and pharmacists working in pharmacies. The findings show that 91% of the pharmacies dispense parallel-imported drugs and that there is a certain amount of scepticism regarding the use of parallel-imported drugs. Most respondents feel that parallel-imported pharmaceuticals may have financial advantages for the individual patient and economic advantages for society at large, but 50% of the pharmacists and 54% of the physicians were of the opinion that parallel-imported pharmaceuticals represented an increased medical risk for the patients. Approximately 15% of doctors and pharmacy staff had knowledge of either incorrect treatment or adverse drug reactions due to the use of parallel-imported drugs. The time used for prescribing and dispensing parallel-imported drugs is longer than for directly imported preparations. The survey shows that approximately every fifth doctor will use the right of reservation in connection with the dispensing of parallel-imported drugs, whereas approximately every fourth pharmacist will disregard the right of reservation.

Drug Costs↗
PubMed1997

A cell-density sensing factor regulates the lifetime of a chemoattractant-induced G alpha-GTP conformation.

Starving Dictyostelium discoideum cells monitor the local density of other starving cells by simultaneously secreting and sensing CMF. CMF regulates signal transduction through the chemoattractant cAMP receptor, cAR1. cAR1 activates a heterotrimeric G protein by stimulating G alpha 2 to release GDP and bind GTP. We show here that the rate of cAMP-stimulated GTP hydrolysis in membranes from cells exposed to CMF is roughly 4 times slower than in membranes from untreated cells, even though the rate of GTP binding is the same. This hydrolysis is abolished in cells lacking G alpha 2. Our data thus suggest that CMF regulates cAMP signal transduction in part by prolonging the lifetime of the G alpha 2-GTP complex.

Animals↗
PubMed1989

Regulation and function of G alpha protein subunits in Dictyostelium.

We have examined the developmental regulation and function of two G alpha protein subunits, G alpha 1 and G alpha 2, from Dictyostelium. G alpha 1 is expressed in vegetative cells through aggregate stages while G alpha 2 is inducible by cAMP pulses and preferentially expressed in aggregation. Our results suggest that G alpha 2 encodes the G alpha protein subunit associated with the cAMP receptor and mediates all known receptor-activated intracellular signal transduction processes, including chemotaxis and gene regulation. G alpha 1 appears to function in both the cell cycle and development. Overexpression of G alpha 1 results in large, multinucleated cells that develop abnormally. The central role that these G alpha proteins play in signal transduction processes and in controlling Dictyostelium development is discussed.

Chromosome Deletion↗
PubMed1989

G-protein-linked signal transduction systems control development in Dictyostelium.

G-protein-linked cAMP receptors play an essential role in Dictyostelium development. The cAMP receptors are proposed to have seven transmembrane domains and a cytoplasmic C-terminal region. Overexpression of the receptor in cells, when the endogenous receptor is not present, results in a 10- to 50-fold increase in cAMP-binding sites. Antisense cell lines, which lack cAMP receptors, do not enter the developmental program. Ligand-induced phosphorylation is proposed to occur on serine and threonine residues in the receptor C-terminus. The kinetics of receptor phosphorylation and dephosphorylation correlate closely with the shift of receptor mobility and the adaptation of several cAMP-induced responses. Two alpha-subunits, G-alpha-1 and G-alpha-2, have been cloned and specific antisera developed against each. Both subunits are expressed as multiple RNAs with different developmental time courses. The mutant Frigid A has a functional defect in G-alpha-2 which prevents it from entering development. We propose that G-protein-linked receptor systems will be a major component in the development of many organisms.

Amino Acid Sequence↗
PubMed1986

Intracellular recording during magnetic field application to monitor neurotransmitter release events: methods and preliminary results.

A method for simultaneous magnetic field application and intracellular recording is presented. A little used method for magnetic field application was exploited; the field generator consisted of a flat copper sheet through which current was passed to generate a magnetic field. The resultant magnetic field was relatively homogeneous, exhibiting a variation of +/- 5%. This compact, current-sheet field generator was mounted on the condensor of a microscope. The current induced in the intracellular electrode was reduced by injecting current equal and opposite to the induced current into the microelectrode. This step reduces the possibility of cellular effects and voltage artifacts due to the induced electrode current. The technique was used to conduct preliminary studies on the effects of extremely low frequency (ELF) linearly and circularly polarized magnetic fields (1.0 Gauss, 60 and 70 Hz) on miniature end plate potential (mepp) frequency (frequency of neurotransmitter release events) of rat flexor digitorum brevis muscle. The same synapse was utilized for both the sham-exposed control and the exposed experimental halves of an experiment. After 10 min of exposure to a 60-Hz linear field, mepp frequency was significantly increased by 12%, but exposure to a 60-Hz circular field did not significantly alter mepp frequency. Exposure to a 70-Hz linear field did not significantly change mepp frequency, but application of a 70-Hz circular field appears to decrease mepp frequency by 4%. These results indicate that both types of magnetic fields can alter mepp frequency, depending upon the frequency and configuration of the field.

Animals↗
PubMed1985

Low-voltage ELF electric field measurements in ionic media.

Low-voltage electric fields were measured in conductive tissue culture media using three techniques: voltage slope, current density-conductivity, and dipole methods. All three methods tested yielded comparable results. However, all three techniques have associated errors. These errors fall into three major categories: those associated with the measurement equipment, those associated with electrodes, and errors in cross-sectional area measurements. Each source of error is discussed so that all can be taken into account during construction and/or testing of exposure equipment.

Culture Media↗
PubMed1983

Submucous lymphatic cysts of the small intestine. An autopsy study.

In 150 consecutive autopsies, submucous lymphatic cysts of the small intestine were demonstrated histologically in 35 cases (23%). The mean age of these 35 cases was 74 years. Lymphatic cysts were found in none younger than 55 years. A solitary lesion was observed in 9 cases, whereas more than 10 cysts were encountered in 14 autopsies. The diameter of the lesions never exceeded ca. 1 cm, and histological examination disclosed cystically dilated lymph spaces only in the submucosa. Studies of the clinical records and the autopsy reports revealed no case with symptoms from the lymphatic cysts, and no case with other diseases of the lymphatic system.

Adolescent↗
PubMedDate not supplied

Physical and mental problems attributed to dental amalgam fillings: a descriptive study of 99 self-referred patients compared with 272 controls.

OBJECTIVE: The physical and mental symptomatology of 99 self-referred patients complaining of multiple somatic and mental symptoms attributed to dental amalgam fillings were compared with patients with known chronic medical disorders seen in alternative (N = 93) and ordinary (N = 99) medical family practices and patients with dental amalgam fillings (N = 80) seen in an ordinary dental practice. METHOD: The assessments included written self-reports, a 131-item somatic symptom checklist; Eysenck Personality Questionnaire, the General Health Questionnaire, and Toronto Alexithymia Scale. RESULTS: The dental amalgam sample reported significantly more physical symptoms from all body regions. Self-reports suggested that 62% suffered from a chronic anxiety disorder (generalized anxiety disorder or panic). Forty-seven percent suffered from a major depression compared with 14% in the two clinical-comparison samples and none in the dental control sample. Symptoms suggesting somatization disorder were found in 29% of the dental amalgam sample compared with only one subject in the 272 comparison subjects. One third of the dental amalgam patients reported symptoms of chronic fatigue syndrome compared with none in the dental control sample and only 2 and 6%, respectively, in the two clinical comparison samples. The dental amalgam group reported higher mean neuroticism and lower lie scores than the comparison groups. CONCLUSION: Self-referred patients with health complaints attributed to dental amalgam are a heterogeneous group of patients who suffer multiple symptoms and frequently have mental disorders. There is a striking similarity with the multiple chemical sensitivity syndrome.

Adult↗