Biomedical subjects

L Eriksson

Publications and source records attributed to L Eriksson.

At least 127 records · Page 7Linked to original sources

PubMed1993

Platelet concentrates in an additive solution prepared from pooled buffy coats. In vivo studies.

Leukocyte-depleted platelet concentrates were prepared from pools of 4 buffy coats on the day after blood collection (BC-PC). The storage medium was composed of citrate phosphate dextrose plasma and a platelet-additive solution. Autologous transfusions of 111In-labelled platelets in 9 healthy volunteers were performed on the day of preparation (day 1) and on day 5. The recovery was 54.6 +/- 8.7 (day 1) and 51.9 +/- 10.4% (day 5), T1/2 was 101 +/- 28 and 61 +/- 9 h, respectively. The survival was 8.3 +/- 1.7 and 5.7 +/- 1.0 days, respectively, using linear plot, and 7.8 +/- 2.0 and 5.8 +/- 0.5 days using the multiple hit method. In a prospective clinical study a comparison of the corrected posttransfusion increments was made between BC-PCs and apheresis-PC, and between fresh (1-2 days) and stored (3-5 days) preparations. No difference was found between BC-PCs and apheresis PCs. However, fresh BC-PCs gave higher increments than stored BC-PCs. A slight numerical difference between fresh and stored apheresis-PCs was not statistically significant. It is concluded that the BC-PC method results in platelets of equal quality to apheresis-PC.

Adult↗

PubMed1993

Regional cerebral blood flow during experimental phobic fear.

Positron emission tomographic measurements of regional cerebral blood flow (rCBF) were used to investigate central nervous system correlates of fear and anxiety. Volunteers with symptomatic snake phobia were studied while exposed to visual phobogenic, aversive, and neutral stimuli. Anxiety ratings and the number of nonspecific electrodermal fluctuations increased as a function of phobic stimulation. Phobic, compared to neutral and aversive, stimulation elevated rCBF in the visual associative cortex. The basal ganglia were not activated more by phobic than aversive or neutral stimulation. However, cortical and thalamic rCBF were always correlated during phobic but not aversive or neutral stimulation. This indicates that the thalamus could be a relay station for phobic stimulus processing and affect.

Adult↗

PubMed1993

Functional capacity of transfused platelets estimated by the Thrombostat 4000/2.

Post-transfusion platelet increment is a useful test for the evaluation of transfusion efficacy. It does not, however, give information about the in vivo platelet function. We have evaluated the in vitro bleeding time (IVBT) using the Thrombostat 4000/2 with ADP as activating agent in 60 platelet transfusions given to 17 chemotherapy-induced severely thrombocytopenic patients. Determinations were performed before and after transfusion of platelet concentrates (PC) prepared from buffy coat. Both fresh and stored platelets resulted in significant reductions of the IVBT already 10 minutes after completed platelet transfusion. In the majority of patients there was a correspondence between IVBT and platelet increment. However, in 30% of the cases there was no improvement of the IVBT despite an increase of the platelet count. Fresh PCs were more effective than stored. The IVBT seems to represent a clear-cut improvement in the possibilities for evaluating and monitoring the effect of platelet transfusion.

Adolescent↗

PubMed1993

Bronchoscopic diagnosis of pulmonary infections in a heterogeneous, nonselected group of patients.

Fiberoptic bronchoscopy with bronchoalveolar lavage and protected specimen brush technique has become an established method for etiologic diagnosis in severe forms of pulmonary infections during recent years. In this study, including 62 bronchoscopies in 53 patients, a standardized program, covering all important pulmonary pathogens, has been evaluated in a heterogeneous group of patients. Results providing therapeutic guidelines were obtained in 53 percent (16/30) of the immunocompromised patients (including 5 bronchoscopies on HIV-positive patients), but only 19 percent (6/32) of the immunocompetent patients (p < 0.001). We conclude that bronchoscopy is of great value for diagnosing pulmonary infections in immunocompromised patients. In immunocompetent patients, the diagnostic yield is lower and the indication for bronchoscopy must be established for each individual patient based on clinical importance, resources, and risk. When bronchoscopy is performed, we believe that a standardized program like ours reduces the risk of missing important pathogens.

AIDS-Related Opportunistic Infections↗

PubMed1993

Renal melatonin excretion in sheep is enhanced by water diuresis.

Diurnal variation in blood melatonin levels and renal melatonin excretion was monitored in five ewes by blood sampling and quantitative urine collection at 2-h intervals. A typical secretory pattern of melatonin was seen both in blood and urine levels and in the renal excretion of melatonin. Serum melatonin levels increased from daytime values of approximately 200 pmol/l to a mean of 800 pmol/l during darkness. Urine flow rate and urine osmolality did not show any clear diurnal rhythm. To examine whether urine flow rate affects renal melatonin excretion at night, urine was collected in three consecutive 30-min fractions, and blood was sampled in the middle of each urine collection period when the sheep were in normal water balance or after hydration. Hydration increased urine flow rate over sixfold and decreased urine osmolality well below plasma osmolality. Glomerular filtration rate, measured as creatinine clearance, did not change. Serum melatonin concentrations did not differ between hydrated and non-hydrated sheep. However, urinary melatonin excretion was 1.1 +/- 0.3 (S.E.M.) pmol/min at midnight in normal water balance, and significantly higher (2.6 +/- 0.4 pmol/min) in the hydrated state. In this study, the validity of urinary melatonin determinations as an indicator of pineal function was confirmed in normal water balance. In addition, our results suggest that a high tubular fluid load during diuresis increases urinary melatonin excretion because of decreased tubular reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Positron emission tomographic studies of central cholinergic nerve terminals.

The aim of this study was to develop a quantitative method for the study of cholinergic nerve terminals in vivo. An 18F-labeled analogue of vesamicol ([18F]FMV) that binds with high affinity to synaptic vesicles from Torpedo electric organ was synthesized and evaluated in vivo in rats and monkeys by positron emission tomography (PET). In rats, the tracer was rapidly cleared from the blood and highly extracted into the brain, where it was specifically and irreversibly bound. In monkeys, a specific binding of the tracer was observed in brain regions known to contain cholinergic nerve terminals. Preinjection of non-labeled vesamicol prevented the cerebral binding of [18F]FMV to a high affinity site in both species. Our results are a major step towards quantitative human in vivo studies of presynaptic cholinergic functions.

Animals↗

PubMed1992

Immunohistochemical evidence of endothelin-1 in human choroid plexus.

An immunohistochemical investigation was carried out on 17 specimens of human choroid plexus obtained post mortem, 1 biopsy of normal choroid plexus including part of the lateral ventricle and 1 papilloma of the choroid plexus removed surgically. The material was fixed in formalin. Paraffin and cryostat sections were used. A polyclonal antiserum to endothelin-1 served as a primary antibody. The avidin-biotin-peroxidase method was applied to demonstrate the immunoreaction. The epithelial cells of the choroid plexuses, the choroid papilloma and most ependymal cells of the lateral ventricle showed a distinct brown reaction product in their cytoplasm indicating antigenic sites to endothelin-1. The reaction was of lesser intensity in the ependymal cells. The connective tissue in choroid plexus was unstained. A positive immunoreaction was present in the walls of some vessels in the choroid plexus in cryostat sections. This is the first report on the presence of antigenic sites to endothelin-1 in the epithelial cells of the human choroid plexus. The role of endothelin in these cells should be investigated to ascertain if the cells synthesize this biologically active peptide or if it is merely bound to receptors in them.

Adult↗

PubMed1992

In vivo distribution of [11C]-busulfan in cynomolgus monkey and in the brain of a human patient.

The in vivo distribution of the antileukemic agent busulfan labeled with the positron-emitting radionuclide carbon 11 was investigated in cynomolgus monkeys and in a human patient using positron emission tomography. After i.v. injection of the radiotracer, its regional uptake was monitored for about 1 h in the monkey's body and, in a separate experiment, in the monkey's brain. The concentration of radioactivity in the liver, which showed the highest levels of all the organs scanned, increased throughout the experiment and was 9-fold that in the brain at the end of the experiment. [11C]-Busulfan rapidly crossed the blood-brain barrier. The radioactivity peaked in both the cortex and the white matter showing a ratio of 1.25, at 3 min but declined quickly to yield a ratio of approximately 1 after 30 min. In the human brain, radioactivity in the cerebellum, cortex, and white matter reached a maximum within 5 min showing a cortex:white matter ratio of 1.6. The activity in the cortex declined to yield a ratio of 1 within 30 min. Of the delivered dose, 20% penetrated into the brain.

Adult↗

PubMed1992

Gamma-aminobutyrate aminotransferase activity in brains of schizophrenic patients.

The activity of gamma-aminobutyrate aminotransferase (GABA-T) was estimated in twelve regions of brains from 22 control subjects and 6 cases with schizophrenia. In the controls, no significant correlation was found between the enzyme activity and age or postmortem interval (PMI) in any of the brain regions studied. In experiments on rat brains, the enzyme activity decreased about 20% during the first 2 hours of storage at room temperature and at 4 degrees C but remained steady thereafter. A similar initial decline in activity in the human brain material cannot be excluded. In the human brains, a slightly lower activity was found in the group below 75 years (n = 8) when compared with the group above 75 years (n = 8). A tendency to higher activities was found in female brains (n = 10) compared with male brains (n = 12). No significant difference in the enzyme activity was found between schizophrenic brains, in any of the regions studied, when compared to controls, matched for age, sex and PMI.

4-Aminobutyrate Transaminase↗

PubMed1992

Temporomandibular joint disk displacement without reduction. Treatment with flat occlusal splint versus no treatment.

A flat occlusal splint has been extensively used in the treatment of patients with temporomandibular joint disk displacement without reduction, but no studies with untreated controls have assessed its effect. We randomly assigned 51 patients with temporomandibular joint pain and arthrographically verified disk displacement without reduction to be treated with a flat occlusal splint or to serve as untreated control subjects in a 12-month clinical trial. Pain symptoms disappeared in about one third of the patients in each group. Another third of the patients in the control group improved. Sixteen percent of the patients in the control group and 40% of the patients treated with a flat occlusal splint were worse at the end than at the beginning of the study. Joint pain and muscle tenderness decreased more frequently in the nontreatment controls than in the treatment group. A statistically significant benefit of a flat occlusal splint over nontreatment control subjects could not be identified in this study of patients with painful disk displacement without reduction. The use of a flat occlusal splint in this patient group should therefore be reconsidered.

Adolescent↗

PubMed1992

Temporomandibular joint diskectomy. No positive effect of temporary silicone implant in a 5-year follow-up.

The purpose of this study was to evaluate the long-term clinical and radiologic effects of a temporary silicone implant after diskectomy of the temporomandibular joint. Forty-three temporomandibular joints in 43 patients with painful disk displacement underwent a diskectomy. A sheet of medical-grade silicone was temporarily placed in 22 patients; 21 patients did not receive an implant. The patients were clinically and radiologically examined 5 years after surgery. On the basis of symptoms and jaw function, they were classified as having good (30 patients), acceptable (8 patients), and bad (5 patients) results. All the patients with bad results and five of the eight patients with acceptable results had received implants. Erosive changes of the condyle or fossa were seen radiographically at follow-up in eight patients, each of whom had received an implant. No positive clinical or radiologic effects of the implants could be identified. The use of a temporary silicone implant after diskectomy of the temporomandibular joint in patients with internal derangement should be seriously questioned.

Adult↗

PubMed1992

Prevalence of osseous changes in the temporomandibular joint of asymptomatic persons without internal derangement.

There is a controversy in the literature regarding the prevalence of osseous changes in the temporomandibular joint (TMJ) of asymptomatic persons. Using cephalometrically corrected tomograms, we assessed one TMJ of each of 34 asymptomatic persons who had no arthrographic or magnetic resonance imaging evidence of internal derangement. Minimal flattening of the condyle or articular eminence was seen in 12 joints (35%). More advanced osseous changes such as erosion, osteophytosis, or sclerosis were not seen in any joint. The findings suggest that generally no osseous changes occur in the TMJ in asymptomatic persons without internal derangement. When osseous changes occur, they are confined to minimal flattenings. Minimal flattening is probably of no clinical significance because the persons were asymptomatic, and arthrography and magnetic resonance imaging showed no evidence of abnormalities in the soft tissues.

Adolescent↗

PubMed1992

Magnetic resonance evaluation after temporomandibular joint diskectomy.

The aim of this study was to investigate the value of magnetic resonance imaging after diskectomy of the temporomandibular joint. Magnetic resonance images were obtained before and 12 months after unilateral diskectomy without disk replacement. Magnetic resonance findings at follow-up were correlated to residual pain. At the follow-up, 20 of 28 patients were free of pain in the joint that had been surgically treated, four patients had mild pain, and four patients had significant residual pain. The magnetic resonance images at follow-up showed that the joint space was filled with soft tissue after diskectomy. In patients without pain at follow-up, this soft tissue had a magnetic resonance signal that was equal or higher than that of the muscles. In the four patients with significant residual pain and in one patient with mild residual pain, the soft tissue in the joint space between the condyle and glenoid fossa had a magnetic resonance signal intensity that was lower than the muscle. On the basis of findings in a previous study, the areas of low signal intensity were interpreted as fibrous adhesions. The study suggests that areas of low signal intensity in the joint space appear to be associated with residual pain and that magnetic resonance imaging could be a valuable tool for assessment of the temporomandibular joint after diskectomy.

Cartilage, Articular↗

PubMed1992

Creation of disc displacement in human temporomandibular joint autopsy specimens.

The purpose of this study was to investigate the possibility of iatrogenically creating disc displacement in the human temporomandibular joint (TMJ). Fourteen fresh TMJ autopsy specimens with superior disc position were selected for the study. The upper and lower joint spaces were exposed via a preauricular incision and two to three superficial mediolateral incisions were made in the inferior surface of the posterior disc attachment (ie, retrodiscal tissue). After these incisions were made it was possible to manually displace the disc anteriorly. To maintain the disc in the anterior position the condyle was positioned against the posterior disc attachment in a manner corresponding to the closed mouth position. The joints were then fixed in this relationship and magnetic resonance imaging (MRI) was repeated using the same scanning plane and scanning parameters as before intervention. After imaging, the joints were cryosectioned to show the degree of disc displacement. Histologic analysis was made of the posterior disc attachment. Postoperative MR images and cryosections showed the disc to be displaced anteriorly in 12 of the 14 joints. Displacement of the disc was complete in eight joints (the entire mediolateral dimension of the joint) and partial (only in the lateral part of the joint) in four joints. The disc remained in a superior position in two joints. Cryosections and histologic analysis showed the incisions in the inferior aspect of the posterior disc attachment to be superficial. The results of this study suggest that the integrity of the inferior aspect of the posterior attachment of the disc to the condyle is essential for keeping the disc in its position superior to the condyle.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

The role of white cells in the transmission of Yersinia enterocolitica in blood components.

The mechanism for the transmission of Yersinia enterocolitica in blood components has been studied experimentally. One hypothesis is that, during a Yersinia infection in the blood donor, bacteria are phagocytosed by white cells (WBCs), but are not killed. After collection of blood from such a donor and component production, the bacteria are present in WBCs for some time, during which the unit appears sterile. Later, when the WBCs disintegrate, the bacteria are released and multiply in the unit. Aliquots of whole blood and buffy coat were inoculated with 100 colony-forming units (CFU) per mL of a Y. enterocolitica strain of type O:3 and left at room temperature for 5 hours. Some aliquots were then WBC-reduced by filtration, while others retained their WBC contents. All aliquots were kept at 4 degrees C for 6 weeks. Meat extract broth culture medium was used as a control. Growth in the range of 2000 CFU per mL was obtained in the broth control by 24 hours, whereas the whole blood and buffy coat units appeared sterile for the first days of storage. After 1 week, a trace of bacteria and, after 4 weeks, massive growth were found in the WBC-containing units but not in the WBC-reduced units. The likely explanation is that the bacteria had been phagocytosed by the WBCs and were thereby hidden and not available for bacterial culture during the first phase of storage. When the WBCs spontaneously disintegrated, bacteria were released and multiplied in the blood units.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Preservation↗

PubMed1992

Atrial natriuretic peptide attenuates pressor but enhances natriuretic responses to angiotensin II in pregnant conscious goats.

This study was designed to examine the actions of ANP in acute, ANGII-mediated hypertension during pregnancy. Effects on blood pressure, blood volume, and renal Na and K excretion were evaluated in conscious goats (n = 6). ANP (2 micrograms min-1), ANGII (0.5 microgram min-1), or ANGII+ANP (doses the same as for each peptide alone) was infused intravenously for 60 min. The pressor response to ANGII was reduced in pregnant goats. This reduction was seen in systolic, but not in diastolic pressure. ANP decreased pressure by 5-10 mmHg both in pregnancy and in non-pregnancy. When ANGII+ANP was infused, blood pressure initially rose as with ANGII but then declined. ANP suppressed only the elevated systolic pressure. Plasma protein concentration and haematocrit was reduced by ANGII but increased by ANP alone or together with ANGII, thereby implying fluid shift into the vasculature by ANGII and opposite movement by ANP. ANGII increased renal Na excretion to 1500 mumol min-1 in non-pregnancy, but only to half of that in pregnancy. ANP alone caused small natriuresis, but enhanced ANGII-induced natriuresis to near 3000 mumol min-1 in both non-pregnant and pregnant goats. In summary, ANP further attenuated the blunted blood-pressure rise due to ANGII in pregnant goats, and reduced plasma volume, but enhanced renal Na excretion as in non-pregnant goats. This implies that with the present combination ANP and ANGII caused a near maximal natriuretic response that was not modified by the systemic cardiovascular changes occurring in pregnant goats.

Angiotensin II↗

PubMed1992

Osteocalcin 24-hour profiles during normal pregnancy.

The interpretation of previous data on osteocalcin during pregnancy has been complicated by the fact that serum levels, at least in nonpregnant women, display a significant circadian variation. In the present study, serum concentrations of osteocalcin were recorded for 24 h in 12 individual women. In 4 nonpregnant women, there were striking diurnal fluctuations during the sampling period, with values ranging from 0.5 to 4.0 ng/ml. One woman who was investigated in the 11th week of pregnancy showed similar fluctuations in osteocalcin concentrations whereas in the 15th and 17th week values were much lower with minor fluctuations. In 4 women investigated during late pregnancy (weeks 34-38), osteocalcin serum levels were extremely low (range 0.2-0.4 ng/ml), often below the detection limit of the assay, and there was no diurnal variation. Also, in 1 lactating woman, osteocalcin serum levels were low (0.3-0.8 ng/ml) and stable. Low osteocalcin values during pregnancy may indicate a reduced bone turnover possibly mediated via an altered estrogen and growth hormone secretion.

Bone Remodeling↗

PubMed1992

Automated blood component preparation with the Opti system: three years' experience.

Removal of buffy coat from the red cell preparations reduces the content of microaggregates and leukocytes and decreases transfusion side effects. However, buffy coat removal is difficult to standardize when performed manually. An automated method using a new type of plastic container system, the Optipac, and a new type of device, the Optipress, greatly improves blood component production. An initial hard centrifugation of the original whole blood provides the best results, leaving approximately 20 ml of plasma and 0.5 x 10(9) leukocytes per unit of red cells suspended in 100 ml of an additive solution (SAG-M). Improved quality and standardization of the products, reduced technician time and better working conditions for the technician are the major advantages as compared to traditional manual technique.

Blood Component Removal↗