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Biomedical subjects

L Eriksson

Publications and source records attributed to L Eriksson.

At least 271 records · Page 15Linked to original sources
PubMed1983

Distinctive biochemical pattern associated with resistance of hepatocytes in hepatocyte nodules during liver carcinogenesis.

Hepatocyte ("hyperplastic") nodules induced in the liver by initiation with diethylnitrosamine and selected by dietary 2-acetylaminofluorene plus partial hepatectomy ("resistant hepatocyte model") have a special pattern of biochemical behavior and metabolic activity different than that seen acutely with many xenobiotics including many promoting agents and carcinogens. The nodule cells show a very low uptake of 2-acetylaminofluorene, relative to surrounding and normal liver, low levels of activity in the cytochromes P-450 and aryl hydrocarbon hydroxylase, high levels of activity in gamma-glutamyltransferase, microsomal epoxide hydrolase, soluble glutathione-S-transferase and soluble UDP-glucuronyltransferase (UDP-GT(1)) and elevated levels of glutathione. This metabolic pattern appears to maximize the resistance of the nodules to xenobiotics generally, such as 2-acetylaminofluorene, and thereby may account for the resistant behavior of nodule hepatocytes to the inhibition of cell proliferation and the cytotoxicity by 2-acetylaminofluorene and other carcinogens. The possible importance of this seemingly new metabolic program in carcinogenesis is discussed briefly.

2-Acetylaminofluorene↗
PubMed1983

Clinical and radiological study of patients with anterior disc displacement of the temporomandibular joint.

Patients displaying temporomandibular joint clicking or with a history of clicking followed by limitation of opening were subjected to clinical and radiological examinations including arthrography. Arthrotomographically the patients were found to have anterior displacement of the disc. In patients with clicking the disc was repositioned in association with clicking during opening. In patients with limitation of opening the disc was constantly displaced anterior to the condyle, blocking anterior condylar translation. The patients with limitation of opening had more pain, more signs of mandibular dysfunction, more hard tissue changes and more frequent perforation and deformation of the disc, compared to patients with clicking only. These findings may justify two different diagnoses, displacement with and without repositioning of the disc on opening. Displacement without repositioning seems to be the more advanced condition and may in some cases be a precursor of osteoarthrosis.

Adolescent↗
PubMed1983

C-11-labeled glucose and its utilization in positron-emission tomography.

Carbon-11-labeled glucose was prepared photosynthetically using the green alga Scenedesmus obtusiusculus Chod. The carbohydrates were extracted from the cells with dilute HCI and the glucose was isolated and purified using high-performance liquid chromatography. The manipulations in the hot cell are described. Analysis of the material (gas liquid chromatography and HPLC) showed that the glucose obtained was radiochemically pure. The total incorporation of the 11CO2 added to the algae was 60-80%. The radiochemical yield of pure carrier-added glucose was approximately 25%, at 40 min after E.O.B. including the HPLC purification and sterile filtration. The C-11 glucose uptake in rat brain was compared with that of commercial D[U-14C]glucose, and preliminary PET studies with D-[11C]glucose in a patient with a brain infarct are presented.

Animals↗
PubMed1982

5-hydroxytryptophol in the cerebrospinal fluid and urine of alcoholics and healthy subjects.

The serotonin metabolite 5-hydroxytryptophol was determined in cerebrospinal fluid and urine of alcoholics and healthy subjects, by a glass capillary gas chromatographic-mass spectrometric method. The urinary excretion rate (14.6 +/- 2.9 pmoles/mumoles creatinine) and urine (109 +/- 20 pmoles/ml) and cerebrospinal fluid (4.12 +/- 0.21 pmoles/ml) concentrations in healthy subjects were established. Only 1% of the 5-hydroxytryptophol in urine occurred in free form. Ethanol ingestion (80, 120 g) by healthy subjects lead to a 20--100-fold increase in the urinary excretion rate of 5-hydroxytryptophol. In cerebrospinal fluid the increase was about 60%. Alcoholics had increased urinary excretion rates and cerebrospinal fluid levels during intoxication, which were in the same range as in intoxicated healthy subjects. During recovery from intoxication, the 5-hydroxytryptophol level in alcoholics decreased, but the CSF levels were still higher than in healthy subjects.

Adult↗
PubMed1982

Histamine and histamine-N-methyltransferase in the goat brain.

Histamine concentrations and histamine-N-methyltransferase (HMT) (EC 2.1.1.8) activities were assayed in the goat brain, since this animal has been used for the purpose of assessing the physiological role of histamine in the central nervous system. The highest histamine concentrations were found in the hypothalamus (616 +/- 88 ng/g), 'thalamus' (244 +/- 41), preoptic area (242 +/- 95) and 'area postrema' (170 +/- 52), and are three to tenfold higher than the average concentration in the whole brain (76 +/- 9). The pineal body and choroid plexus contained very high concentrations of histamine (5800 and 5400 ng/g, respectively) and the pituitary gland had about the same as the hypothalamus (564 +/- 248 ng/g). There was little variation in the HMT activity in various parts of the brain and in the glands. In the cerebrospinal fluid both histamine concentration and HMT activity were very low, some increase occurred post mortem, but not within 20 minutes of death. The results indicate that the distribution of histamine and that of HMT in the goat brain are fairly similar to those in other mammalian brains, supporting the assumption that histamine might have a physiological function in the brain, especially in the hypothalamus.

Animals↗
PubMed1982

Positron emission tomography with 68Ga-EDTA in the diagnosis and localization of csf fistulas.

Five patients with cerebrospinal fluid (CSF) rhinorrhea were investigated with computed tomography (CT) and positron emission tomography (PET) to localize the site of a CSF fistula. After intrathecal injection of 10 MBq of 68Ga-EDTA, radioactivity was demonstrated in the basal cisterns. In three cases, the site of the fistula was visualized with PET. It is not always possible to demonstrate a CSF leakage with CT cisternography (CTC) using metrizamide, particularly in cases with minute fistulas or intermittent CSF rhinorrhea. With further experience and improved PET techniques, it may be possible to detect even very small fistulas.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1982

Determination of object contour from projections for attenuation correction in cranial positron emission tomography.

A contour-finding algorithm is described by which the object periphery is outlined in positron emission tomography (PET) scans. The positions of maximum slopes are determined in the projections. These positions are shown to correspond well to the borders of the activity region. By backprojecting these points in the projections into the image plane, the size and shape of the region of activity must be outlined. Cord lengths across this region are then determined for attenuation correction. The accuracy of the algorithm has been tested on 10 patients with both PET and computed tomography (CT) examinations. Points on the periphery of the skull, as determined with the contour-finding algorithm in PET, coincided with those determined by CT, with a standard deviation of 1.5 mm and a maximum deviation of 3.5 mm. In testing the influence of the skull bone on the PET values, it was found that ignoring the higher attenuation coefficient of bone, 5 mm thick, in the attenuation correction caused an error in the determination of activity of 11% peripherally and 6% centrally in the object. These errors could be reduced to less than 1% by increasing the assumed attenuating region by 4.5 mm.

Brain↗
PubMed1982

Renal urea handling in goats fed high and low protein diets.

Four female goats first were fed a high protein diet and later a low protein diet. Renal urea handling was studied during feeding of both diets. Glomerular filtration rate was measured with [hydroxymethyl-carbon-14] inulin. Glomerular filtration rate dropped about 60% when nitrogen intake was restricted. Urea concentration of plasma fell from 6 mM on high protein diet to .6mM on low protein diet. On low protein diet the rate of urea filtration at the glomeruli was only 4% of that on high protein diet, 22 versus 519 mumol/min. In addition, tubular urea reabsorption in percentage of filtered urea rose up to 92% on low protein diet. As a result of all these renal changes following dietary nitrogen restriction, urinary urea excretion was only .6% of urinary urea excretion on high protein diet. In goats as in other ruminants, renal mechanisms effectively contribute to urea conservation during protein deprivation.

Animals↗
PubMed1982

Hepatic cholesterol metabolism in obesity: activity of microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase.

Obesity is often associated with an elevated total body cholesterol synthesis. In order to evaluate the role of hepatic cholesterogenesis in this phenomenon, we assayed the rate-limiting step in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase in the microsomal fraction of liver biopsies obtained operatively from ten morbidly obese (relative body weight greater than 155%) subjects. Eighteen normal-weight patients (relative body weight less than 120%) with cholesterol gallstones served as controls. Hepatic HMG CoA reductase activity, expressed as pmol X min-1 X mg protein-1, was 60% higher in the obese subjects compared to the gallstone patients (P less than 0.05). Microsomal protein concentration was lower in the obese patients, so that enzyme activity calculated per gram liver was not significantly different between the two groups. However, mevalonate formation, expressed in terms of total organ activity, was higher in the obese than in the nonobese group. The results suggest that the liver is a major contributor to the increased cholesterol production seen in obesity.

Adult↗
PubMed1982

The effect of protein deprivation on the validity of creatinine and urea in evaluation of renal function. An experimental study in the goat.

Reliability of plasma creatinine and urea concentrations and clearances in evaluation of renal function was studied in four goats on two diets of equal energy content but differing in protein (14% and 2% of dry matter). Glomerular filtration rate (GFR) was measured with [hydroxymethyl-14C] inulin. GFR was 88.6 +/- 8.4 ml/min on the high protein diet and 36.9 +/- 2.9 ml/min on the low protein diet. The endogenous creatinine clearance values agreed with the inulin clearances on both diets. Reduction of protein intake was followed by significant increase in plasma creatinine concentration (from 83.8 +/- 3.6 mumol/l during high protein diet to 124.6 +/- 3.5 mumol/l during low protein diet). Plasma urea concentration, urea clearance and urea excretion fell to a very low level during low protein intake. Endogenous creatinine clearance seems to be suitable for measurement of GFR even during protein deprivation when GFR is decreased.

Animals↗
PubMed1981

Spinal, trigeminal, and cortical climbing fibre paths to the lateral vermis of the cerebellar anterior lobe in the cat.

The spinal, trigeminal and cortical climbing fibre projection to the lateral vermis of the cerebellar anterior lobe in the cat has been investigated. The b zone, which occupies a one mm wide band in the lateral vermis, receives a somatotopically arranged input. Successively more rostral segments (tail, hindlimb, thorax, forelimb and trigeminal nerves) project to successively more medial microzones. The b zone receives an input through each of three spino-olivocerebellar paths (SOCPs) ascending in the ventral, dorsal and dorsolateral funiculi (VF, DF and DLF). In the b zone, the hindlimb input is bilateral through the VF-SOCP and ipsilateral through he DF- and DLF-SOCPs. The forelimb input is bilateral through the VF-SOCP, ipsilateral through the DLF-SOCP and lacking from the DF-SOCP. The trigeminal input is bilateral. Medial to the b zone in lobule V is the x zone, which receives an input from the ipsilateral forelimb through the DF- and DLF-SOCPs. The climbing fibres to the x zone are collaterals of the climbing fibres projecting to the c1 zone in the pars intermedia and paramedian lobule. The climbing fibre input from the cerebral sensorimotor cortex to the lateral vermis matches the spinal input. The lateral and medial parts of the b zone receive a bilateral input from hind- and forelimb cortical areas, respectively. The x zone receives an input from the contralateral forelimb area. The functional significance of the converging paths is discussed.

Afferent Pathways↗
PubMed1981

Cardiovascular and behavior changes after ICV infusion of TRH in the conscious goat.

Thyrotropin releasing hormone was infused during 5 min into the lateral brain ventricle (ICV) of conscious goats in doses ranging from 125 to 4000 ng. Changes in blood pressure, heart rate and behavior were studied. TRH in doses of 500--4000 ng raised the mean blood pressure and both the magnitude and the duration of the response was related to the dose. The onset of the rise occurred in average 8 min after the start of the infusion. The heart rate fell somewhat with all doses. No consistent changes were observed in the respiration rate. TRH caused several behavioral changes beginning about 6 min after the start of infusion. The goats often decreased their locomotor activity. They were frequently bleating except after the lowest dose. These results support the view that TRH affects several vital functions in the central nervous system.

Animals↗
PubMed1981

Acetaldehyde penetrates the blood-liquor barrier of goats.

Goats received ethanol or acetaldehyde via carotid arterial infusions. Cerebrospinal fluid (CSF) was sampled for a lateral cerebral ventricle and blood from a jugular vein. Ethanol infusions produced only negligible levels of acetaldehyde in blood and CSF, but acetaldehyde infusions resulted in high levels. In contrast to ethanol, acetaldehyde was rapidly eliminated from both blood and CSF after discontinuing the infusion. The results indicate that even small amounts of acetaldehyde easily penetrate the blood-liquor barrier of goats.

Acetaldehyde↗
PubMed1981

Head fixation device for reproducible position alignment in transmission CT and positron emission tomography.

A head-positioning device allowing accurate position transference between computed tomography and positron emission tomography is described. A base plate is fixed to the patient's head through either an individual mold or screws into the calvarium. This base plate fits onto the headholders of the two devices, thus ensuring that scans are taken at the same level. Using the regular software, the coordinates of an anatomic structure may be determined and transferred between the two images.

Humans↗
PubMed1981

Lack of conformity in the behaviour of platelets during normal storage conditions at 22 degrees C.

Platelets prepared from citrate-phosphate-dextrose blood under normal routine conditions and concentrated to 1,000-1,600 x 10(9) x 1(-1) varied considerably in their capacity to acidify the medium. Serotonin uptake was well maintained for 5 days provided that adenosine 5'-triphosphate was within 50% of normal and pH was above 6.0. A strong release of platelet factor 4 was occasionally seen in relation to preparation. In some preparations the platelet factor 4 was well maintained for 5 days, in others a sudden or gradual release was seen during storage. The investigation indicates that differences in the quality of routinely prepared platelets occur during preparation and storage which are insufficiently well explained and controlled.

Adenosine Triphosphate↗
PubMed1981

Positron emission tomography with 68Ga-EDTA compared with transmission computed tomography in the evaluation of brain infarcts.

The diagnostic value of positron emission tomography (PET) was evaluated in 41 examinations of 40 patients. 68Ga-EDTA was used as a positron source. The findings were correlated with those of conventional of CT scanning. A clearly pathologic accumulation of 68Ga-EDTA was detected in 29 of 41 PET scans. The precontrast CT scans were negative in 11 and non-conclusive in one patient. CT after administration of contrast medium was performed in 29 patients. Of these, 21 had a clearly pathologic PET scan and 14 had visible contrast enhancement on CT examination. The injury of the blood-brain barrier thus was better demonstrated with PET than with CT. The topologic diagnosis was, however, better demonstrated at CT. It seems that CT and PET are supplementary examinations and that PET is superior to CT in the detection of injury of or absence of the blood-brain barrier.

Adult↗
PubMed1980

Vasopressin release by histamine in the conscious goat.

The vasopressin releasing activity of histamine was studied in conscious goats. Histamine was infused into the brain ventricles or intravenously and serial blood samples were taken from the jugular vein. Plasma vasopressin was assayed by a radioimmunoassay for arginine vasopressin (AVP). After i.v. infusions of 300 micrograms and 1 mg of histamine, a pronounced increase in plasma AVP up to greater than 100 pg/ml occurred. This was considered secondary to hypotension, since it only occurred with doses that markedly decreased arterial blood pressure. When given i.c.v. even smaller doses of histamine increased plasma AVP without any concomitant decrease in blood pressure. There was a simultaneous decrease in renal free water clearance in hydrated animals. Up to the dose of 300 microgramshistamine, the increase in AVP was modest. Histamine 1 mg i.c.v., given to either hydrated or non-hydrated animals, increased plasma AVP about tenfold, up to 38.3 +/- 23.3 pg/ml and 56.7 +/- 19.0 pg/ml, respectively. In individual experiments the correlation between the AVP level and the degree of antidiuresis was less apparent, since the kidney seemed to be very sensitive even to small changes in plasma AVP. It is concluded that histamine releases vasopressin through a central mechanism and it is reasonable to suppose that histamine may act as a neurotransmitter in the vasopressin releasing system.

Animals↗