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Biomedical subjects

S Blika

Publications and source records attributed to S Blika.

At least 19 recordsLinked to original sources

The frequency distribution of the glaucoma tolerance limit.

The probability of having glaucoma may be expressed by the quotient p = (number of eyes with glaucomatous damage)/(total number of eyes). p has been calculated for different IOP levels, within a total population and also within groups with and without pseudo-exfoliation (PE). The resulting quotients were plotted versus IOP. Random irregularities were reduced by regression analysis, using the equation for the logistic distribution. The resulting sigmoid curves demonstrated that the probability p of having glaucomatous damage at a certain IOP is highest in the PE group. In the total material, the glaucoma probability p was 0.5 at IOP = 27.1 mmHg, and at IOP = 25.3 and 28.0 mmHg in the groups with and without PE, respectively. The frequency distributions of the glaucoma tolerance limit have been computed from the glaucoma probability curves.

Aged

The middle-Norway eye-screening study. II. Prevalence of simple and capsular glaucoma.

In this population-based screening study, dealing with 1941 persons above 64 years of age from three different municipalities, the overall open-angle glaucoma prevalence was found to be 8.3%. The prevalence in the separate areas (7.0%, 8.6%, and 9.5%) were not statistically different. Roughly 30% of the population with pseudo-exfoliation syndrome had glaucoma, and 4.2% had ocular hypertension, whereas the corresponding figures for those without pseudo-exfoliation were 4% and 0.8%, respectively. The high glaucoma rates are partly due to the high pseudo-exfoliation prevalence in the area. The prevalence of the capsular glaucoma increased towards a maximum between 75 and 79 years of age, whereafter the curve declined. This may indicate reduced survival time of glaucomatous patients.

Aged

Frequency distribution of IOP. Analysis of a material using the gamma distribution.

The results of a population-based (age greater than or equal to 65 years) examination of the frequency distribution of IOP are reported. 3726 eyes in 1887 individuals were included in the examination. By consistent use of conventional, well-defined criteria, glaucoma was diagnosed in 6.4% of the individual eyes. In the total material, the average IOP was 18.0 mmHg. Average IOP was 28.7 mmHg in eyes with glaucomatous damage, vs 17.2 mmHg in the normal eyes. Variance of IOP was much higher in the glaucoma group as compared with the normal group. The IOP frequency distribution curve did not fit with a Gaussian curve; it was asymmetric, skewed to the right. The distribution curve obtained by plotting the recorded frequencies was disturbed by irrelevant irregularities, both random and systematic. The irregularities could be evened out by the application of regression analysis, using the equation for the gamma distribution. The IOP frequency distribution is well represented by a gamma distribution curve. The fit is improved by excluding eyes with extremely high and low IOP.

Aged

The probability of having glaucoma at different IOP levels.

The probability of having glaucoma is indicated by the quotient (number of eyes with glaucoma)/(number of eyes in the total population). This quotient was calculated for each value of IOP. The number of eyes at each IOP value was taken from IOP frequency distribution curves for glaucomatous and normal eyes, calculated from values obtained by a population survey. By plotting the probability of having glaucoma vs IOP, a sigmoid curve was obtained. The curve indicates that while the glaucoma probability is near zero at IOP = 18 mmHg, it is 0.5 at 27-28 mmHg, and the probability approaches 1, i.e. certainty, at an IOP around 35 mmHg. The frequency distribution of the tolerance limit of IOP was calculated by derivation of this curve. The distribution of IOP tolerance limit was close to a normal distribution with average = 27.9 mmHg and standard deviation = 3.2 mmHg.

Aged

Pseudo-exfoliation, IOP and glaucoma.

On the basis of a glaucoma survey in a total population greater than or equal to 65 years of age, the IOP in eyes with and without pseudo-exfoliation (PE) has been compared. The average IOP was 22.2 mmHg in eyes with PE versus 17.4 in eyes without. The corresponding averages in eyes without glaucomatous damage were 18.6 and 17.1 mmHg, and in eyes with glaucoma 31.5 and 25.5 mmHg. The IOP elevation connected with the PE process was 4.8, 1.5, and 6.0 mmHg in the total, normal and glaucomatous population, respectively. The IOP frequency distribution curves of these 3 groups were compared. The right shift of the distribution curves of the PE groups was more pronounced at high pressure levels. The PE process seems to elevate the IOP particularly in eyes with a high IOP, which is in correspondence with hydrodynamical laws. At a certain IOP, the probability of having glaucomatous damage was higher in eyes with PE than in those without, indicating an increased vulnerability of PE eyes to an elevated IOP. PE may be a glaucoma risk factor also on its own, i.e. independent of the pressure elevation connected with this syndrome.

Aged

Outpatient anterior chamber lens implantation.

100 outpatient and 143 inpatient intracapsular cataract extractions with anterior chamber lens implantation were examined 6 months post-operatively. 74 (74%) in the former and 107 (75%) in the latter achieved visual acuity greater than or equal to 0.5. Excluding non-surgical pathology, 93% in the outpatient group and 98% in the inpatient group had a visual acuity greater than or equal to 0.5 (P = 0.12). There were no significant differences in post-operative complications except for the incidence of cystoid macular edema. Six (6%) of the outpatient and 1 (0.7%) of the inpatient procedures had cystoid macular edema that resulted in a visual acuity below 0.5 (P = 0.02).

Ambulatory Surgical Procedures

The Middle-Norway eye-screening study. I. Epidemiology of the pseudo-exfoliation syndrome.

This is the first population-based PE prevalence study allowing comparison of observations from different geographical areas. The prevalence of the PE syndrome for persons above 64 years of age was found to be 10.2, 21.0 and 19.6% in three municipalities lying distinctly apart. Of 343 married couples the man was PE-positive in 36, the woman in 34, and both in 12 cases. One of the 12 couples was excluded because the spouses were cousins. The observed number of 11 couples is significantly higher (P = 0.022) than expected assuming independent occurrence of PE syndrome. Two homozygote pairs of twins were found in this material, both of them discordant for the presence of PE syndrome. This fact along with the discrepancy between observed and expected numbers of PE positivity in both spouses may indicate environmental influence on the distribution of the syndrome.

Aged

The occurrence of simple and capsular glaucoma in Middle-Norway.

The records of all patients with simple and capsular glaucoma who visited our clinic in the period from 1.1.1972 to 31.12.1982, and who were alive at the 31.12.82, have been evaluated. In the population older than 49 years 0.54% had simple and 0.74% had capsular glaucoma, equally distributed on men and women. In average near 60% had capsular glaucoma, with great variation in different municipalities. Highest figures were found in a belt reaching from the coast into the inland. Both simple and capsular glaucoma showed increasing occurrence till 75-80 years, thereafter the curves decline.

Demography

The penetration of ceftazidime into the inflamed rabbit eye.

Acute endophthalmitis was unilaterally induced in 8 rabbits by intravitreal injection of 5 micrograms Escherichia coli endotoxin. A reproducible increase in aqueous humour polymorphonuclear neutrophils and total protein content was observed after 24 h (mean +/- SD: 2400 +/- 274 X 10(6)/l and 3.7 +/- 0.4 g/l, respectively). In the opposite eye only minor changes occurred, making it suitable as a paired control. The intraocular penetration of ceftazidime was then studied in 30 rabbits after i.v. injection of 50 mg/kg body weight. The mean penetration into aqueous humour of the eyes with and without endophthalmitis was 64 and 10%, respectively. In the vitreous body the corresponding penetration was 5 and 1%. The concentration of ceftazidime achieved in the intraocular structures was sufficient to inhibit the growth of pathogens, i.e. Enterobacteriaceae, commonly responsible for intraocular infections.

Animals

Ascorbic acid determination in serum and aqueous humour by high-performance liquid chromatography.

High-performance liquid chromatography on a Supelcosil LC-HN2 analytical column in weak anion exchange mode has allowed separation of ascorbic acid, in less than 5 min, from other interfering substances in serum and aqueous humour. UV monitoring at 254 nm enables ascorbic acid to be detected at 20 pmol level. A method for determination of ascorbic acid concentration in serum and aqueous humour is described, and values from 10 cataract patients are reported.

Aged

Senile cataract and ascorbic acid loading.

Serum, aqueous humour, and lens ascorbic acid levels were determined by high-performance liquid chromatography in cataract-, closed-angle glaucoma-, and aphakic patients. The total number of 108 patients were subdivided into different groups. In several groups the pre-operative serum and aqueous amounts were tested, whereafter patients in some groups were loaded with ascorbic acid orally. Finally, a second test was performed on samples taken during operation. It turned out that the ascorbic acid concentration mechanism in cataractous eyes needed more than 12 h for maximum reaction on the loading stimulus. The slow reaction is surprising compared to other species, and it may reflect an affection of the secretory process itself in this disease.

Aged

Penetration of ceftazidime into the normal rabbit and human eye.

The penetration of ceftazidime into the aqueous humour and the vitreous body of the rabbit eye, after intravenous (i.v.) bolus or subconjunctival injection, was investigated. A dose of 50 mg/kg body weight was administered. After i.v. administration the mean penetration into the aqueous humour was 13% of the plasma values. After subconjunctival injection into the left eye, mean levels of 14% and 25% of the plasma concentrations were found in the right and left eye, respectively. The concentrations in the vitreous body were in all cases below the ceftazidime detection limit (1 mg/l), i.e. less than 1% of the plasma levels. The mean penetration of ceftazidime into human aqueous humour (measured during cataract extraction) was 19% after 2 g i.v. bolus injection. Ceftazidime levels sufficient to inhibit the growth of most pathogens commonly responsible for intraocular infections, including Pseudomonas spp., were consistently found in the aqueous humour. However, inadequate concentrations were achieved in the vitreous body.

Aged

ABO-blood groups and D-antigen in simple and capsular glaucoma.

ABO-blood groups and Rh-factor (D-antigen) were determined in 236 patients with POAG, 104 simple and 132 capsular glaucoma. There was a statistical significant difference in the ABO-distribution between the two glaucoma subgroups, and also between the capsular-group and our control material. The simplex-group did not differ from the control material in this respect. For the Rh-group (D-antigen) no differences were found, neither between the two glaucoma subgroups nor between each of them and a reference material.

ABO Blood-Group System

Pharmacokinetics and tissue penetration of ceftazidime: studies on lymph, aqueous humour, skin blister, cerebrospinal and pleural fluid.

The elimination kinetics and penetration of ceftazidime into skin blister and lymphatic fluid were studied in nine healthy volunteers following a 1 g iv bolus injection. From the concentration time curve in plasma the following pharmacokinetic parameters (mean +/- S.D.) were calculated: elimination half-life 1.85 +/- 0.33 h; area under the curves 127 +/- 12 mg . h/l; apparent volume of distribution: 21.1 +/- 2.61; total plasma clearance: 133 +/- 13 ml/min and renal clearance: 109 +/- 7 ml/min. Urine recovery after 8 h was 82% of the administered dose. Nearly the same elimination rate constant, half-life and area under the curve were demonstrated for blister fluid and lymph. The penetration of ceftazidime into cerebrospinal fluid (n = 19), aqueous humour (n = 21) and pleural effusions (n = 5) were studied in patients after a 2 g iv bolus injection. In patients with normal meninges (n = 14) the penetration was poor: the concentrations were less than 1 mg/l. In patients with meningitis (n = 5) levels of 18, 17, 16, 1 and 0.8 mg/l were found. Aqueous humour penetration was satisfactory, and a mean concentration of 11 +/- 4 mg/l corresponding to a penetration ratio of 19% was found. The penetration of ceftazidime into large pleural effusions was also good with concentrations from 17 +/- 3 to 28 +/- 2 mg/l, corresponding to a mean penetration ratio of 38%.

Adult