Jørg Mørland

Inhibition of fracture healing by indomethacin in rats

Abstract. The effect of indomethacin (2 mg/kg/day) on the healing of closed unimmobilized femoral fractures was examined in rats. A standard femoral fracture was produced in 205 male adolescent rats, and three different experiments were done. In a long‐term experiment, the rats were treated with either indomethacin or placebo for 29 days and fracture healing followed for a maximum of 91 days. In two short‐term experiments, the rats were treated with either indomethacin or placebo for a week and followed for a maximum of 122 days. The effect of age was studied in one experiment. Indomethacin plasma levels were about 1 μg/ml in the indomethacin‐treated animals. In the long‐term experiment, indomethacin inhibited fracture healing (P< 0·006) and increased the angulation between the femur fragments. In the short‐term experiments indo‐methacin inhibited fracture healing (P< 0·033) and increased the interfragmentary angle as well as fracture instability. All untreated fractures healed within 10 weeks in younger rats (210 g), whereas only 44% healed in older rats (295 g).

Inhibition of protein synthesis by ethanol in isolated rat liver parenchymal cells.

Abstract Hepatocytes were isolated from perfused rat livers. 0.8 · 106–5.0 · 106 cells/ml were incubated at 37°C in the absence and presence of ethanol (50 mM). 1. (1.) The incorporation of l -[U-14C]valine and l -[3,5-3H2]tyrosine into both stationary cell protein and proteins released to the medium was reduced by ethanol. 2. (2.) This effect was neither mediated by reduced uptake of labelled valine nor diminished specific radioactivity of the precursors. 3. (3.) The effect was present in amino acid-free media, making possible effects of ethanol on uptake of other amino acids an unlikely explanation of the reduced incorporation. More probably, ethanol primarily affects the protein-synthesizing machinery of the liver cells. 4. (4.) No effects of ethanol were found when liver cell proteins were prelabelled with l -[U-14C]valine and the radioactivity remaining in the protein after inhibition of further protein synthesis with cycloheximide (5 μg/ml) was measured. In other prelabelling experiments performed without cycloheximide, ethanol did not affect the amount of radioactive valine remaining within and released from liver protein. It was concluded that ethanol reduced hepatocyte protein synthesis without affecting protein degradation. Hepatocytes appear more sensitive to this effect of ethanol than intact liver preparations, when the present observations are compared with previous results.

Rearrest rates among Norwegian drugged drivers compared with drunken drivers

The rearrest rates among Norwegian drugged (n=1102) and a group of drunken drivers (n=850) (BAC: 0.16-0.19%) apprehended during 1992, were 57% (n=629) and 28% (n=238), respectively, when followed prospectively for 7 years. The most important risk factors for recidivism among drugged drivers were previous arrests for drugged or drunken driving (rearrest rate among previous arrests: 73%, no previous arrest: 42%), multi-drug detection at selection (multi-drug: 62%, single drug: 41%), sex (male: 61%, female: 35%) and age (below 36 years: 60%, 36 years and older: 44%). Most of the recidivist drugged drivers were rearrested during the year of selection (21%), followed by 13, 7 and 6%, retrospectively, during the following years. When followed both retrospectively and prospectively for a period extending from 1984 to 1998, 71% (n=779) and 40% (n=344) of the selected drugged and drunken drivers, respectively, were arrested two or more times.

Activity of alcohol dehydrogenase and acetaldehyde dehydrogenases in the liver and placenta during the development of the rat.

The ontogenetic development of the enzymes alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenases (ALDH I and II) was followed in rats. ADH could be detected just before birth and increased gradually to reach 82% of adult values at 47 days. ALDH I and II were present from day 15 of gestation, increased rapidly at birth, and reached 80-90% adult values at 47 days. The ratio between ALDH and ADH activities decreased gradually during ontogenesis. The relative subcellular distribution of all enzymes was identical before birth, 7 days after birth and in adults. The placental activities of ADH and ALDH I and II were studied at 15 and 20 days of pregnancy. ADH could not be detected in placentas. Low activities of ALDH I and II were present in placentas studied at 15 days of gestation, and still lower activities were found in placenta at 20 days.

Isolated rat hepatocytes in suspension: Potential hepatotoxic effects of six different drugs

Isolated rat hepatocytes in suspension were studied with regard to various measures of hepatic toxicity. We compared enzyme leakage (ASAT, ALAT, LDH), cell viability (trypan blue exclusion), intracellular ATP content, and incorporation of 14C-valine into stationary and export proteins while the cells were exposed to six different drugs at two different concentrations. The drugs were oxytetracycline, paracetamol, carbon tetrachloride, ethanol, methotrexate and fentanyl. The results were compared to known in vivo responses, in particular to see whether concentrations resulting in dose-related in vivo effects would similarly affect the functions tested in vitro. Leakage of enzymes exhibited a graded increase with a corresponding rise in the concentration of oxytetracycline and carbon tetrachloride. Reduction in incorporation of 14C-valine into cell and medium proteins showed a similar graded effect with rising concentrations of parcetamol, carbon tetrachloride, and ethanol. Intracellular levels of ATP gradually decreased with increasing concentrations of carbon tetrachloride and ethanol. An obvious reduction in viability was only registered with increasing concentrations of carbon tetrachloride, while paracetamol tended to give a similar response. We found no major discrepancies between already known in vivo effects and our in vitro results when testing paracetamol, carbon tetrachloride, ethanol, methotrexate, and fentanyl. We could not, however, demonstrate inhibition of protein synthesis by oxytracycline at the concentrations tested. No single measurement was adequate for testing all drugs. The test of 14C-valine incorporation into hepatocyte export proteins plus LDH leakage seemed to constitute a useful combination in detecting drug toxicity in hepatocyte suspensions.

Incorporation of labelled amino acids into proteins of isolated parenchymal and nonparenchymal rat liver cells in the absence and presence of ethanol

Parenchymal and nonparenchymal cells were isolated from perfused rat livers and incubated at 37 degrees C in the absence and presence of ethanol (50 mM). 1. Nonparenchymal cells prepared by means of centrifugation showed a higher rate of incorporation of L-[U-14C]valine into protein than nonparenchymal cells prepared by means of pronase. Cells prepared by the former method were used for further studies. 2. Protein degradation was present in suspensions of both parenchymal and nonparenchymal cells evidenced by increasing levels of branched amino acids in the intracellular and extracellular compartment during cell incubation. 3. The rate of cellular protein synthesis (corrected for precursor pool specific radioactivity) was of the same order of magnitude in nonparenchymal and parenchymal cells when expressed as nmol valine incorporated per mg protein. This rate was also close to the value found in intact liver by other workers. 4. Approximately 25% of the total radioactivity incorporated during incubation for 2 h was found in proteins released to the medium from parenchymal cells, while the corresponding figure for nonparenchymal cells was 3.5%. 5. Ethanol inhibited incorporation of labelled valine into stationary and medium proteins of parenchymal cells. No such effects were found in nonparenchymal cells. 6. Nonparenchymal cells did not metabolize ethanol while parenchymal cells did, shown by changes in lactate/pyruvate ratio and medium pH. It was concluded that nonparenchymal cells are capable of synthesizing proteins at a rate comparable to that found in parenchymal cells. Protein synthesis in parenchymal cells was inhibited by ethanol, but nonparenchymal protein synthesis was unaffected. This difference may be linked to the ability of the former cell type to metabolize ethanol.

Does chronic alcohol consumption really induce hepatic microsomal gamma-glutamyltransferase activity?

Summary Ethanol feeding of rats for 6–7 weeks was accompanied by elevated plasma and liver γ-glutamyltransferase (GT) activities compared to enzyme activities in control animals fed carbohydrates isocalorically. Similar differences in hepatic GT activity were present after feeding these diets for 1 or 4 weeks. In all instances the difference between ethanol-fed and control rats was due to a reduction of GT activity in the animals fed the control diet, while ethanol-fed rats had GT activities close to pre-experimental values. Since neither treatment influenced the subcellular distribution of hepatic GT activity, no evidence for induction of microsomal GT activity from a pretreatment level due to ethanol was present.

Road traffic accident risk in patients with diabetes mellitus receiving blood glucose-lowering drugs. Prospective follow-up study

Aim  To investigate, at a national level, whether patients using insulin or oral glucose‐lowering agents had an increased risk of road traffic accidents compared with non‐users.

Hepatic amino acid levels in rats after long-term ethanol feeding

Abstract Male Wistar rats were given ethanol to provide 25–33 per cent of the total calories consumed. Control rats were pair-fed either sucrose or lipid. The experiments lasted for 5–9 weeks. In experiment A protein constituted about 15 per cent of the calories and all diets were given until the moment of sacrifice. In experiment B the same diets were fed to similar groups of animals, but a control diet was given to all three groups as the only food the last day before death. Protein provided 10 per cent only of the total calories in this experiment due to a higher intake of ethanol. In experiment C the protein content of the basic diet was enhanced and both ethanol and control rats covered about 25 per cent of their caloric demands by protein. In this experiment, too, a control diet was given to both groups the last day before sacrifice. Long-term ethanol feeding reduced the incorporation of intraperitoneally injected 14 C-labelled valine into hepatic protein in all three feeding models. There were, however, no consistent changes in the concentrations of the individual hepatic amino acids when ethanol treated and control rats were compared. It is concluded that reduced hepatic protein synthesis accompanying long-term ethanol consumption is not a direct consequence of lack of a single or several amino acids, and that moderate to severe consumption of ethanol does not disturb the normal pattern of free amino acids in the rat liver.

Metabolism of ethanol and acetaldehyde in parenchymal and non-parenchymal rat liver cells

Abstract Suspensions of isolated parenchymal (P) and non-parenchymal (NP) cells were prepared by collagenase perfusion followed by centrifugation of the primary cell suspension. Suspensions of P cells were able to metabolize ethanol (8–16 nmoles/min/10 6 viable cells) while NP cells did not metabolize ethanol at all. Acetaldehyde was metabolized in P-cell suspensions at rates ranging from 14 to 20 nmoles/min/10 6 viable cells. Some acetaldehyde metabolism also occurred in NP-cell suspensions (0.18–0.33 nmoles/min/10 6 viable cells). In accordance with these studies on ethanol and acetaldehyde metabolism we found alcohol dehydrogenase activity only in homogenates of P cells, and aldehyde dehydrogenase activity in homogenates of P cells was 20 times higher per cell than in homogenates of NP cells. It was concluded that the P cells of rat liver are responsible for ethanol metabolism and probably also responsible for most, if not all metabolism of acetaldehyde arising from ethanol oxidation. Biochemical effects which are consequences of ethanol metabolism are probably not found in NP cells.