Search PubMed⌕ Search

Biomedical subjects

S Holm

Publications and source records attributed to S Holm.

At least 217 records · Page 12Linked to original sources
PubMed1986

In vitro method for measuring synthesis rates in the intervertebral disc.

A method for culturing intervertebral disc tissue in vitro under conditions that control changes in hydration and minimize loss of proteoglycans has been developed. Disc slices were enclosed in small-pore dialysis tubing and incubated in medium containing polyethylene glycol (PEG). By varying the PEG concentration, different external swelling pressures could be applied to the tissue. The rate of glycosaminoglycan synthesis in rabbit and dog disc was then measured using [35S]sulphate as a precursor. Synthesis rates varied with final hydration of the tissue, and the highest rates were found at hydrations close to those found in vivo. Under conditions of controlled hydration, rabbit nucleus has a higher rate of glycosaminoglycan synthesis than annulus. However, the rates measured in sagittal slices of dog disc decreased from the outer to the inner regions of the anterior annulus, reaching a minimum value in the nucleus and then increasing again in the posterior part of the annulus. The results show that in the intervertebral disc, measured rates depend on culture conditions.

Animals↗
PubMed1986

Gross anatomy of the mandibular joint and masticatory muscles in the domestic pig (Sus scrofa).

The mandibular joint (MJ) and masticatory muscles in 15 domestic pigs, aged 1 year, were investigated during and after dissection. The joint consisted of a fossa, disc and condyle surrounded by a ligamentous capsule. The fossa was almost flat, slightly convex antero-posteriorly and concave medio-laterally; the disc was biconcave and the condyle oval. The long axis of the condyles formed an anteriorly orientated angle to the frontal plane. The masticatory muscles were similar to human ones except for the pig zygomatico-mandibular muscle. The resemblance between the anatomy of the porcine and human joint and masticatory muscles makes the pig a useful animal for functional studies of the masticatory system.

Animals↗
PubMed1986

Effects of tumor-load and malnutrition on myocardial function in the isolated working rat heart.

Marked differences in cardiac associated morbidity and mortality have been reported between patients with and without malnutrition. Tumor-associated cachexia may impair heart function, which further aggravate host wasting and thereby create a vicious circle. The aim of this study was to evaluate to what extent a malignant tumor may influence heart function under well-defined experimental conditions. The perfused working rat heart was used as a model. Study groups of freely-fed sarcoma-bearing rats, starved and protein-calorie malnourished (PCM) non-tumor rats were compared to freely-fed control animals. All groups of malnourished animals (tumor-bearing, starved and PCM) lost significant amounts of body and heart mass compared to freely-fed controls. Loss of heart contractile mass in tumor-bearing rats and malnourished animals did not lead to impaired heart function in any respect. The rate of oxygen uptake was significantly higher under all experimental conditions in perfused hearts from tumor-bearing rats compared with hearts from starved, PCM and freely-fed control rats. Oxygen uptake per left ventricular work was significantly higher in tumor-bearing rats but significantly lower in starved and PCM rats compared with control animals. Norepinephrine at various concentrations (10(-9)-10(-5) mol/l) in the perfusate stimulated the contractility and the left ventricular peak pressure significantly more in hearts from malnourished animals compared with that of freely-fed controls. The results show that adaptive functional changes can be recorded in the isolated perfused rat heart from sarcoma-bearing rats and after a period of comparatively acute undernutrition in non-tumor rats. A malignant tumor or the associated malnutrition does not induce impaired pumping performance despite a reduction in contractile heart mass. Increased oxygen consumption in hearts from tumor-bearing animals may contribute to elevated energy expenditure in a cancer-bearing host.

Animals↗
PubMed1986

Effect of captopril on the cerebral circulation in chronic heart failure.

Cerebral blood flow (CBF) was investigated in 8 patients with chronic heart failure (CHF) (functional class III) and in twelve controls before and after administration of 6.25 mg and 25 mg captopril, respectively. In four controls, CBF was measured by the intracarotid xenon-133 (133Xe) injection technique using stationary external detectors, while inhalation of 133Xe and single photon emission computer tomography was used in the remaining cases. In the control group, the cerebral metabolic rate for oxygen was calculated from measurements of the arterio-venous oxygen difference as well. Mean CBF was significantly (P less than 0.01) lower in the patients with CHF as compared to our controls. Following captopril administration the mean arterial blood pressure decreased in the CHF patients, ranging from 5 to 40%. Three patients showed decreases of blood pressure to values of 56, 65, and 76 mm Hg, but no symptoms of cerebral hypoperfusion were elicited. CBF was unchanged after captopril administration, even in the patients showing a marked reduction in blood pressure. In the control group, the blood pressure, CBF and the cerebral metabolic rate for oxygen remained essentially constant following captopril administration. It is concluded that the cerebral circulation is well preserved during captopril treatment of chronic heart failure. This might be explained by a shift of the lower limit of CBF autoregulation towards lower blood pressure levels.

Adult↗
PubMed1986

Influence of polysaccaride capsule and ionic strength on buoyant density of group B streptococci.

Density fluctuation during the cell cycle was investigated with group B streptococcus (GBS), type Ia, in isotonic medium. Maximum density occurred at late lag-phase, with a minimum at the middle of logarithmic growth. During the stationary phase the density remained stable. The buoyant density of serotypes Ia, Ib, II, III and a rough variant was determined by means of gradient centrifugation. In an isotonic milieu at the early stationary phase, the density of the strains varied in the range between 1.06 and 1.11 g/ml. Low ionic strength reduced the density of all strains. Neuraminidase-treatment increased the buoyant density of types Ia, Ib and III. The same pattern was seen in isotonic and hypotonic medium, although low ionic strength markedly augmented these differences. The influence of tonicity and neuraminidase-treatment was most prominent with types Ia and III, which may be due to relatively thicker polysaccaride capsules in these types.

Centrifugation, Density Gradient↗
PubMed1986

In vitro aminoglycoside resistance of gram-negative bacilli and staphylococci isolated from blood in Sweden 1980-1984.

The in vitro susceptibility to gentamicin, tobramycin, amikacin and netilmicin in septicaemia isolates was followed during 1980-1984 in 6-8 Swedish laboratories. The bacterial distribution was similar over the years and was dominated by Escherichia coli and staphylococci. Resistance to gentamicin was found in 2.3-3.6%, to tobramycin in 1.4-3.4%, to amikacin and netilmicin in 0.5-0.9%. Production of aminoglycoside modifying enzymes was observed among resistant strains.

Amikacin↗
PubMed1985

Coexposure to toluene and p-xylene in man: uptake and elimination.

Eight male subjects were experimentally exposed to toluene, p-xylene, and a combination of toluene and p-xylene in order to study the influence of coexposure and exposure to different levels of each solvent on their uptake and elimination. The exposures were performed for four hours at exposure levels equivalent to or lower than the Swedish threshold limit value for toluene, 300 mg/m3 (3.2 mmol/m3). During and after the exposure, solvent concentrations were measured in blood and in expired air. In addition, the pulmonary ventilation rate was measured during the exposure. Decreases in the blood/end exhaled air concentration ratio were found for both toluene and p-xylene when given in combination compared with separate exposure. The total solvent uptake relative to the exposure level was decreased after exposure to the higher solvent concentrations, and the apparent clearance was also decreased after exposure to the higher concentrations of solvent. Finally, the blood solvent concentrations were lower at the end of the exposure compared with the maximal concentration during each exposure condition. In the kinetics of toluene and p-xylene the total amount of toluene or p-xylene, or both, seems to be of major importance. The change in blood/end exhaled air concentration ratio may indicate an effect of coexposure.

Adult↗
PubMed1985

Metabolic adaptation to reduced muscle blood flow. II. Mechanisms and beneficial effects.

Increased mitochondrial enzyme activities are induced in rat muscles after common iliac artery ligation, giving a 76-93% blood flow reduction, and 6 days of intermittent muscle stimulation. To elucidate the trigger for this enzyme induction, the acute alterations in the metabolite pattern during contractions were evaluated. More pronounced changes in intramuscular PO2, creatine phosphate, ATP/ADP, lactate/pyruvate, and glycogen were observed in the ligated leg. The benefit of this enzyme alteration was investigated with the hindlimb perfusion technique. Enzymatically adapted and control legs were perfused at reduced flow during contractions. Similar oxygen consumption and glucose uptake but a significantly lower lactate release were observed in the adapted legs. A lower lactate level, lactate/pyruvate, and a better maintained creatine phosphate/creatine were found in the adapted soleus muscle. The results demonstrate that the increase of mitochondrial enzymes is preceded by acute alterations in energy metabolites due to intermittent hypoxia during contractions at reduced flow and that this enzyme adaptation allows the muscle tissue to maintain a lower anaerobic metabolism and a better energy state during exercise.

Adaptation, Physiological↗
PubMed1985

Studies of the lumbar vertebral end-plate region in the pig.

The vertebral end-plates and the epiphyses from the lumbar region of the spine in juvenile pigs were studied. Cell density of the hyaline cartilage of the vertebral bodies was measured as well as cartilage thickness. The relative bone content in the region of the nucleus pulposus was calculated. A certain negative interrelationship between cartilage thickness and cell density of the hyaline cartilage of the vertebral bodies was found. The relative bone content of the cranial epiphysis was higher than that of the caudal epiphysis in the same motion segment at all levels of the lumbar spine. The difference was pronounced down to 2 mm from the cartilage/bone interface.

Animals↗
PubMed1985

Tobramycin therapy--two or three doses per day?

11 patients with moderate infections were treated with bolus injections of tobramycin in a fixed dose of 4.5 mg/kg and day for 8 days. The patients were randomized to injections every 8 h (TID) for 4 days followed by injection every 12 h (BID) or vice versa. Serum concentrations were measured on day 2 of each regimen. The TID regimen gave peak levels less than 4 micrograms/ml in 5/11 patients, mean value 4.2 micrograms/ml. With the BID regimen 2 patients had peaks less than 4 micrograms/ml, mean value 5.9 micrograms/ml. The BID regimen seems preferable when treating patients with normal renal function. The bolus injections were well tolerated.

Adult↗
PubMed1985

Dynamic SPECT of the brain using a lipophilic technetium-99m complex, PnAO.

The lipophilic 99mTc-labeled oxime propylene amine oxime (PnAO) should, according to recent reports behave like 133Xe in the human brain. This study compares SPECT images of the two tracers in six subjects: four stroke cases, one transitory ischemic attack case and one normal subject. Technetium-99m PnAO was injected i.v. as a bolus of 15 to 25 mCi. The distribution was followed over 10-sec intervals using a highly sensitive, rapidly rotating SPECT (Tomomatic 64) and compared to 133Xe flow maps. Upon arrival of the PnAO bolus to the brain, a high uptake was found in brain tissue with high cerebral blood flow followed by rapid washout. In the stroke cases, low flow areas were equally well visualized by both tracers. Two dissimilarities were seen in the initial pictures: PnAO visualized the cerebral veins and showed a lesser contrast of gray:white matter uptake. The results suggest that PnAO has a high yet incomplete brain extraction yielding a flow dominated initial distribution with limitations mentioned.

Adult↗
PubMed1984

A purge-and-trap method for the analysis of acetone in biological tissues.

A method for the detection and quantitation of acetone in biological tissues is described. The solvent was extracted with nitrogen gas from the biological specimen and adsorbed on a porous polymer (Porapak Q). The acetone content of the adsorbent was determined by conventional gas chromatographic analysis (FID) after heat desorption. The reliability of the method was tested both with in vitro- and in vivo-exposed specimens. A complete recovery was obtained after in vitro additions of acetone. The method error was about 9% as calculated from both in vitro and in vivo experiments. Acetone concentrations ranging between 17 nmol/g tissue in nonexposed animals and 1.8 mumol/g tissue in mice exposed to acetone vapor were determined.

Acetone↗
PubMed1984

Non-invasive assessment of the presence and severity of cardiac amyloidosis. A study in familial amyloidosis with polyneuropathy by cross sectional echocardiography and technetium-99m pyrophosphate scintigraphy.

Twelve patients with familial amyloidosis with polyneuropathy were examined both by cross sectional echocardiography and by technetium-99m pyrophosphate scintigraphy to assess involvement of the heart non-invasively. All 12 patients had echocardiographic abnormalities. The most prominent findings were highly refractile myocardial echoes, thickened heart valves, and increased thickness of the heart walls. Four patients had abnormal myocardial uptake of technetium-99m pyrophosphate. The remaining eight had equivocal or no myocardial uptake and were considered to have normal scintigrams. A certain amount of amyloid is probably required to produce an abnormal scintigram, although lesions with less amyloid can evidently be identified by echocardiography. Neither the duration of polyneuropathy nor its severity showed any relation to the echocardiographic or scintigraphic findings. It is concluded that cross sectional echocardiography is superior to technetium-99m pyrophosphate scintigraphy in detecting cardiac involvement in familial amyloidosis with polyneuropathy and that these results may also be applicable to other forms of amyloidosis.

Adult↗
PubMed1984

Muscle respiration during exercise.

The importance of oxygen as a limiting factor for the mitochondrial respiration in contracting skeletal muscle was studied. The oxygen tension was found to decrease in human gastrocnemius muscle during leg exercise, and the magnitude of the decrease was a function of the intensity as well as the frequency of the muscle contractions. Significant relationships were found between the intramuscular oxygen tension and various muscle metabolites such as the [phosphocreatine], the [ATP]/[ADP] ratio, and the [lactate]/[pyruvate] ratio. This suggests that the oxygen tension measured in the extracellular compartment is of importance for the intracellular energy, and redox state, in exercising muscle. These findings were confirmed in an experimental model where the oxygen delivery could be varied in a more predictable way. Thus, perfusing the contracting rat hindlimb at various oxygen partial pressures showed significant relationships between the oxygen delivery and the [phosphocreatine] and the [lactate] in the gastrocnemius muscle, respectively.

Aged↗
PubMed1984

Red Deer Regional Dietetic Services Program.

The Regional Dietetic Services Program coordinated by the Red Deer Regional Hospital Centre is described. The Program became a reality in June 1978, in response to requests for professional dietetic assistance from the rural hospitals located in Central Alberta. The program objectives were defined, standards were determined, duties and responsibilities of Red Deer Regional Hospital Centre (the 'Agency') and the 'User' hospital were clarified, and a yearly contract was established. The dietetic consulting program was then presented to interested rural administrators and board members. When the first commitment was received, the Red Deer Regional Hospital Centre hired a part-time dietitian to implement the program. As a spin-off benefit, this program provided an avenue through which a dietitian could participate part-time in the professional and contribute to the community in a rewarding way.

Alberta↗