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J Olsson

Publications and source records attributed to J Olsson.

At least 55 records · Page 3Linked to original sources
PubMed1997

A new generation of algorithms for computerized threshold perimetry, SITA.

PURPOSE: The purpose of this work was to develop a new family of test algorithms for computerized static threshold perimetry which significantly reduces test time without any reduction of data quality. METHODS: A comprehensive visual field model constructed from available knowledge of normal and glaucomatous visual fields is continuously updated during testing. The model produces threshold estimates and also estimates of the certainty to which the threshold is known at each point. Testing is interrupted at each test location at predetermined levels of threshold certainty. New time-saving methods are employed for estimation of false answers, and test pacing is optimized. After completion of the test, all threshold estimates are re-computed, taking into account the complete body of patient responses. Computer simulations were used to optimize the different parameters of the new algorithms, to evaluate the relative importance of those parameters, and to evaluate the performance of the algorithm as a whole in comparison with a standard algorithm. RESULTS: Simulated test results obtained with this algorithm were slightly more accurate than those of the Humphrey Full Threshold test algorithm. The number of simulated stimuli presented was reduced by an average of 29% in normal fields and 26% in glaucomatous fields. Actual clinical test time should be further reduced, since the influence of the improved timing algorithm was not included in the simulations. CONCLUSIONS: We applied new methods which take available knowledge of visual field physiology and pathophysiology into account, and employ modern computer-intensive mathematical methods for real time estimates of threshold values and threshold error estimates. In this way it was possible to design a family of testing algorithms which significantly reduced perimetric test time without any loss of quality in results.

Algorithms↗
PubMed1997

A perimetric learner's index.

PURPOSE: Certain individuals need earlier perimetric experience before producing normal fields on automated static threshold perimetry. Mid-peripheral depressions and an unaffected central field are typical findings in such cases. We have devised a learner's index, to detect defect patterns that may be due to such perimetric inexperience. METHODS: The central visual field was partitioned into 5 concentric zones and averages of deviations from the age-corrected normal threshold values were studied in each zone. The third test session in 74 randomly selected normal subjects provided an experienced reference material. Visual field results typical of normal individuals lacking perimetric experience were represented by the first field test obtained from each of 7 subjects ('learners') from the same group, who showed significant learning during three test sessions. A linear discriminant function, learner's index, was constructed that discriminates between typically experienced and typically inexperienced field results in normals. RESULTS: Average deviation from age-corrected normal threshold increased with increasing eccentricity in the learner's initial fields. Clinical examples illustrate the intended use of the new index. CONCLUSIONS: The learner's index highlights those first field tests from eyes with normal visual fields, that deviate significantly from a normal experienced result in the direction of a learner's result. Patients showing significant learner's index are candidates for repeated visual field testing.

Adult↗
PubMed1997

Survival after high-dose intraperitoneal infusion of glycine solution in the mouse.

We used an animal model to study whether glycine prompts death after absorption of irrigating fluid by the extravascular route. Mice were divided into groups of 10 and given an intraperitoneal infusion of 200, 225, 250, 275 or 300 ml/kg of glycine 1.1%, 1.5% or 2.2%. With all infused volumes, the chance of survival was better after infusion of glycine 1.1% and glycine 1.5% than after glycine 2.2%. The overall death rates were 10%, 16% and 46%, respectively. Logistic regression analysis showed that the outcome was significantly and independently affected by both the glycine concentration and the infused volume. We conclude that the glycine concentration of an irrigating fluid deposited in the peritoneal cavity is important to the chance of survival. The poorest chance is obtained with glycine 2.2%.

Animals↗
PubMed1996

Saliva-mediated binding in vitro and prevalence in vivo of Streptococcus mutans.

The contention that the colonization of oral tissues requires the adhesion of bacteria is undisputed, but adherence can only be studied quantitatively in vitro. It has never been seriously challenged whether the adherence phenomena measured in vitro reflect differences in levels of in vivo colonization. The objective of this study was to investigate the adherence-promoting ability of saliva from persons harbouring Strep. mutans in the range from non-detectable levels to more than 106 colony-forming units/ml. Saliva-mediated adherence of Strep. mutans is promoted by high molecular-weight glycoproteins, agglutinins, which also causes aggregation of the bacteria. Adherence and aggregation of Strep. mutans was investigated individually using parotid saliva from 41 persons. Heavily colonized individuals did not promote adherence better than those with relatively few indigenous bacteria. Aggregation was found to be less rapid with parotid saliva from the heavily colonized individuals (p < 0.05). The results indicate that parotid saliva primarily affects the in vivo prevalence of Strep. mutans by clearing the bacteria from the mouth rather than promoting adherence.

Adult↗
PubMed1996

Saliva mediated adherence, aggregation and prevalence in dental plaque of Streptococcus mutans, Streptococcus sanguis and Actinomyces spp, in young and elderly humans.

Salivary components in the pellicle mediate bacterial adherence to the tooth. Such components may also aggregate bacteria in saliva and prevent them becoming established in dental plaque. In the present study, the adherence and aggregation of Streptococcus mutans strain Ingbritt, S. sanguis strain 10556 and Actinomyces viscosus-strain 19246 mediated by parotid and whole saliva from groups of young and elderly people were examined. Significant differences were found between test strains, salivary secretions and age groups. S. sanguis 10556 and A. viscosus 19246 generally adhered more strongly than S. mutans Ingbritt, which adhered better to pellicles from parotid saliva than from whole saliva Strain 19246 bound in higher numbers to parotid saliva pellicles from elderly compared to young individuals. Strain 10556 adhered better to whole saliva than parotid saliva pellicles, and the difference was significant among the young individuals, indicating reduced adherence ability in elderly whole saliva. The streptococci were aggregated by parotid and whole saliva, and S. sanguis aggregation was less with whole saliva from the elderly than from the young participants. Besides a correlation between whole saliva aggregation of S. mutans and proportions of bacteria in plaque, no correlations were found for the individual binding properties of saliva and prevalence of bacteria in vivo. However, the level of saliva-mediated adherence in vitro was in the following order: S. mutans. Actinomyces S sanguis, which corresponded to their isolation frequency in plaque. These findings emphasize the importance of initial adherence to salivary receptors in bacterial colonization on teeth. Further studies are needed to reveal if individual patterns in the in vitro binding characteristics of saliva lead to variation of colonization in vivo.

Actinomyces viscosus↗
PubMed1996

Survival after high-dose intravenous infusion of irrigating fluids in the mouse.

OBJECTIVES: Fluid absorption is still a potentially fatal complication in patients undergoing transurethral resection of the prostate. We induced experimental overhydration in animals to find out which of three widely used irrigating fluids is most strongly associated with survival. METHODS: The survival and incidence of voiding was studied in 120 mice after an intravenous infusion of either 225, 250, 275, or 300 mL/kg of glycine 1.5%, mannitol 5%, or sorbitol 2% plus mannitol 1% over 60 minutes. RESULTS: Only 20% of the animals survived the glycine solution, whereas the overall survival rate after mannitol was 60%. The corresponding figure for sorbitol plus mannitol was 32%. Logistic regression analysis showed that survival was significantly more likely after infusion of mannitol 5% compared with the other irrigating fluids. The likelihood of survival was also higher in the animals in which the infusion induced diuresis and when the smaller volumes of irrigating fluid were given. CONCLUSIONS: Mannitol 5% offered the best chance of survival.

Animals↗
PubMed1996

Ethanol monitoring of the transurethral resection syndrome.

Ethanol monitoring is a fairly new method of assessing fluid absorption during transurethral resection of the prostate (TURP). By using an irrigating fluid containing a trace amount of ethanol, the absorption can be measured by expired-breath tests. We describe a TURP in which large-scale absorption of irrigating fluid occurred despite the use of a pressure-warning device set at 10 cm H2O. The surgeon decided to terminate the operation because 1.0 liters of fluid had been absorbed over 10 minutes, and another 1.0 liter was absorbed during the 10 minutes required to conclude the surgery. The high absorption rate suggests that continued resection would have promoted a severe transurethral resection syndrome. This was prevented by the indication given by the breath test, whereas the pressure-warning device failed to do so.

Absorption↗
PubMed1996

Do low molecular weight heparin and dextran increase the blood loss in transurethral resection of the prostate?

OBJECTIVE: To evaluate whether the use of dextran or the combination of low molecular weight heparin and dextran increases the blood loss in elective transurethral resection for benign prostatic hyperplasia. PATIENTS AND METHODS: This open randomized controlled study included 198 patients operated under spinal anaesthesia who were allocated to four groups differing in the combination of prophylactic treatment used for thrombosis and for the substitution of blood loss. The prophylactic treatment was either dalteparin sodium, continued each day until mobilization, or 3% Ringer dextran-60 just before operation and continued with 6% dextran-70 for 2 days post-operatively, and the volume substitute was Ringer dextran or Ringer's acetate. Thus, the four treatments (by prophylaxis and volume substitute, respectively) were dalteparin and Ringer's acetate, dalteparin and dextran, dextran and Ringer's acetate, and dextran and dextran. The haemoglobin lost to the irrigation fluid was measured and used to calculate blood loss. RESULTS: Patients receiving dextran had a larger post-operative and total blood loss than those who did not. The need for transfusion did not differ between the treatment groups. CONCLUSION: The combination of dalteparin and dextran was not associated with an increased blood loss above that with dextran alone.

Aged↗
PubMed1996

Analysis of ethanol in expired air during low-flow isoflurane anaesthesia.

Monitoring of ethanol concentration in expired air is a method for assessing fluid absorption during transurethral prostatic surgery and endometrial resection, but the validity of this technique has not been studied in low-flow ventilation systems. For this purpose, we have compared the concentration-time profiles of ethanol in expired gas and in venous blood during an i.v. infusion of 0.4 g kg-1 of ethanol over 30 min in 10 women during isoflurane anaesthesia and in the awake state. Anaesthesia increased the ethanol concentration in expired gas by 13% and in venous blood by 34%. The expired gas-blood difference during infusion was abolished, and the central volume of distribution for ethanol was reduced from 20.9 to 8.6 litre, on average. We conclude that breath sampling during low-flow isoflurane anaesthesia reflects an alcohol load well, but that a change in ethanol disposition makes the values slightly higher than in the awake state.

Adult↗
PubMed1996

Endolymphatic sac surgery: why we do not do it. The non-specific effect of sac surgery.

Three of the present authors described a trial in 1981 which showed that cortical mastoidectomy was as effective as an endolymphatic sac shunt in controlling vertigo in patients with Ménière's disease both on a short-term as well as a long-term basis. The hearing was not influenced by the treatment and any change was considered to be the result of time, rather than the effect of the surgery. Upon perusal of the literature only two other studies exist resembling our study, and they both reached the same conclusion, that sac surgery is at best non-specific and at worst of no value. None of the numerous other studies published have convinced the authors that sac decompression is specific in nature. We have also looked at ECoG as a means of proving the specificity of sac operations and come to the same conclusion that the existing information is conflicting and confusing, and cannot be used to prove anything about sac surgery. The present conclusion is therefore that in treating patients with Ménière's disease anything goes, even sac surgery.

Audiometry, Evoked Response↗
PubMed1996

Serum levels of endometrial proteins during transcervical resection of the endometrium.

OBJECTIVE: To study the potential for dissemination of endometrial tissue substances during transcervical resection of the endometrium (TCRE). DESIGN: Prospective study. SETTING: One university and two county hospitals. PARTICIPANTS: Forty-eight women with dysfunctional bleeding. INTERVENTIONS: The serum levels of two endometrial proteins, insulin-like growth factor binding protein-1 (IGFBP-1) and placental protein 14 (PP14), were measured before and every 10 min during the operations. Blood loss was also measured by a photometer together with absorption of the irrigating fluid containing glycine 1.5% and ethanol 1% by expired-breath tests, and serum sodium and volumetric fluid balances. MAIN OUTCOME MEASURES: Linear correlations between changes in IGFBP-1 and PP14 during TCRE and operating parameters such as operating time, blood loss and fluid absorption. RESULTS: The baseline levels of IGFBP-1 were normal but PP14 could only be detected in one third of the patients, which was due, in part, to pre-operative treatment with danazol. The highest levels of IGFBP-1 and PP14 during surgery correlated positively with the baseline concentrations. Fluid absorption (median 405 ml, range 0-2177) was the only surgical factor associated with increasing serum levels of endometrial proteins. CONCLUSION: Absorption of the solution used to irrigate the uterus is associated with dissemination of endometrial products in the bloodstream during TCRE.

Adult↗
PubMed1996

Irrigating fluid absorption from the intact uterus.

OBJECTIVE: Absorption of irrigating fluid may occur through severed blood vessels during endometrial resection. We studied whether irrigating fluid can also be absorbed through the undamaged uterus. PARTICIPANTS: We studied 25 women, aged 28-46 years (mean 38 years), who underwent elective laparoscopic sterilisation under general anaesthesia. INTERVENTIONS: In 15 women blue-stained irrigating fluid containing glycine 1.5% and ethanol 1% was applied to the uterine cavity under increasing pressure. Laparoscopy was employed to see when fluid emerged from the Fallopian tubes. Another 10 women had their Fallopian tubes clamped before the fluid pressure was raised, and systemic absorption was detected by measuring the serum glycine concentration. RESULTS: Passage of fluid through the Fallopian tubes occurred in 14 of the 15 patients at a uteroabdominal pressure gradient of 40 mmHg (n = 4), 80 mmHg (n = 4), 120 mmHg (n = 3), and 160 mmHg (n = 3), respectively. The fluid passage rate ranged between 0.5 and 13 (mean 6.4) ml min-1. Of the women with clamped Fallopian tubes, 8 of 10 showed an increase in the serum glycine level of 60% at a pressure gradient of 160 mmHg, and of 120% at 200 mmHg. CONCLUSIONS: Uterotubal and transendometrial passage of small to moderate amounts of irrigating solution occurred frequently at the intrauterine fluid pressures normally used during endometrial resection.

Absorption↗
PubMed1996

Early detection of 'endometrial resection syndrome'.

We report a patient who developed symptoms of fluid overload after having absorbed 3 litres of irrigating fluid during transcervical resection of the endometrium. Four methods were used to measure the absorption at 10-min intervals throughout the operation. There were strong intercorrelations between the results of these monitoring methods, which consisted in breath ethanol analyses and measurements of the serum sodium and glycine concentrations and of the volumetric fluid balance. However, the ethanol method was easiest to perform and provided immediate results. This monitoring gave the operating team as much as 45 min to prevent further absorption before it became large enough to elicit a transcervical endometrial resection syndrome.

Absorption↗
PubMed1995

Peroxisome proliferation and associated effects caused by perfluorooctanoic acid in vitamin A-deficient mice.

Vitamin A-deficient male mice were treated for 10 days with 0.02% perfluorooctanoic acid (PFOA) in their diet. The effects of this highly potent peroxisome proliferator on peroxisomal palmitoyl-CoA oxidation and lauroyl-CoA oxidase activities were reduced by 3.1-7.5 times in comparison to the values obtained with mice receiving a vitamin A-adequate diet. The activity of peroxisomal catalase was virtually unaffected by vitamin A deficiency and treatment with PFOA had no significant effect on this activity in vitamin A-adequate or vitamin A-deficient mice. However, vitamin A deficiency itself caused a more than 800% increase in cytosolic catalase activity. Thus, the percentage increase caused by PFOA on cytosolic catalase activity was reduced 12.6 times in vitamin A-deficient mice compared to the increase in vitamin A-adequate mice, although the total absolute activities were similar. These findings suggest that the peroxisome proliferation caused by this peroxisome proliferator is highly dependent on the vitamin A status of the mouse.

Acyl-CoA Oxidase↗
PubMed1995

Immune parameters in a longitudinal study of a very old population of Swedish people: a comparison between survivors and nonsurvivors.

As a part of an ongoing longitudinal investigation, this study examined relationships between survival and selected immune system parameters in a sample (n = 102) of very old individuals (86-92 years at the time of initial immune system data collection). Analyses were performed comparing initial time-point measurements from those individuals who were alive (n = 75) and those who were deceased (n = 27) two years after initial data collection. Immune system measurements consisted of determination of peripheral blood lymphocytes and lymphocyte subsets, as well as T-cell responses to activation by Concanavalin A. Cluster analysis identified a subgroup associated with nonsurvival which indicated characteristics that included: poor T-cell proliferative responses, high CD8 percentages, and low CD4 and CD19 percentages. This multivariate analysis suggested that combinations of immune system parameters predict two-year survival otherwise not apparent when single immune system parameters were evaluated in the elderly.

Aged↗
PubMed1995

Ethanol monitoring of irrigating fluid absorption in transcervical resection of the endometrium.

BACKGROUND: We evaluated the precision in using ethanol to indicate and quantify absorption of irrigating fluid during transcervical resection of the endometrium. METHODS: The ethanol concentration in the expired breath, the serum sodium level, the blood loss and the volumetric fluid balance were measured over 10-min periods during 62 operations. A solution containing glycine 1.5% and ethanol 1% was used to irrigate the uterus. RESULTS: Most principles previously outlined for ethanol monitoring in transurethral prostatic surgery could also be applied in endometrial resection. In the 21 patients who showed the intravascular pattern of ethanol changes, the breath alcohol measurement corrected for absorption time predicted the volume of irrigant absorbed (up to 2,531 ml) with a standard error of 230 ml at the end of any 10-min period of absorption. Repeated measurement of serum sodium indicated intravascular fluid absorption with practically the same precision as the breath test. Extravascular absorption was found in 14 patients. In these operations, the volume of irrigant absorbed (up to 1,767 ml) could be predicted with a standard error of 92 ml from the ethanol concentration at the plateau level attained after absorption had occurred. CONCLUSION: Ethanol monitoring is precise enough to allow monitoring of irrigating fluid absorption in endometrial resection.

Abdomen↗
PubMed1995

Physiology of cumulative defect curves; consequences in glaucoma perimetry.

Purely diffuse field loss is a controversial sign of early glaucoma. Cumulative defect curves have been proposed to distinguish between diffuse and localized visual field loss. In such curves, pointwise deviations from the normal reference field are ranked. The deviations are then compared with normative limits for each rank. The ranking leads to a complete loss of spatial information and ignoration of pointwise physiological threshold variability. We believed that this might impair the curves' intended ability to distinguish diffuse and localized types of defects. The lower 5% normative limit was estimated for each rank in the cumulative defect curve using Humphrey 30-2 tests of 88 subjects from the Statpac normal database. For each rank we identified those two test points (among the total of 6512 (74 test points in each of 88 subjects)) from which the 5% limit was calculated. The average eccentricity, eccrank, of those two points was then determined at each rank. For lower to intermediate ranks eccrank was spread out from center to periphery. When instead the 20 highest ranks (most depressed points) were considered eccrank was much concentrated peripherally. Our normative limits were subsequently used to evaluate field results in 101 patients with glaucoma. In this glaucoma evaluation group, the largest deviations were often encountered in central or paracentral scotomas, in sharp contrast to the more peripheral position in the normative group. These deviations often failed to reach the cumulative defect curve limits which originated from points in the mid-periphery where normal variability is large. At present, cumulative defect curves are not optimized to distinguish diffuse and localized field loss.

Adult↗