Pentti Koskela

Seasonal and age variation in the metabolism of the common frog, Rana temporaria L. In Northern Finland

Abstract 1. 1. The weight and the glycogen and lipid contents of the liver and fat body are highest m autumn at the onset of wintering and smallest in spring after spawning, while the water and protein contents of the liver show the opposite trend. 2. 2. Liver glycogen content is lower in mature females than in males. 3. 3. Phosphorylase activity in liver and lipase-esterase activities in liver and fat body vary depending mainly upon environmental temperature being lowest during wintering. 4. 4. Phosphorylase activity correlates positively and lipase-esterase activity and lipid content in the liver correlate negatively with the size and age of the frog. 5. 5. Liver glycogen content increases towards northern latitudes with the longer wintering period.

Seasonal changes in calcium, magnesium, copper and zinc content in the liver of the common frog, Rana temporaria L

Abstract 1. 1. The values for calcium, magnesium, copper and zinc content calculated per unit weight are lowest during wintering and highest during the spring and summer, partly as a result of seasonal changes in the weight and water content of the liver. 2. 2. The total calcium, magnesium and zinc figures are highest during the summer and autumn due to feeding and rapid metabolism. 3. 3. Total copper remains practically constant throughout the year in the liver of the male, but in the female there is a clear spring maximum connected with egg-laying. 4. 4. Sex differences are found in the dry weight liver calcium and magnesium content during the summer, apparently due to the development of the ovaries.

Effect of thermal acclimation on seasonal liver and muscle glycogen content in the common frog, Rana temporaria L.

1. 1. Normal, prolonged and early wintering in the laboratory (+3°C in the dark until 6 months) and thermal acclimation (+3°C in the dark and +15°C in daylight until 1 month) in summer and winter showed that the seasonal rhythm in liver and muscle glycogen content in the common frog, Rana temporaria L., is similar in nature and in the laboratory, the glycogen being accumulated in late summer and autumn, and consumed in winter and spring. 2. 2. The glycogen consumption is faster, however, and the increase in glycogen values in autumn is smaller in the laboratory than in nature, due to a greater amount of movement and starvation even in summer in the laboratory. 3. 3. The increase in glycogen stores in the laboratory at the same time as in nature suggests some kind of endogenous rhythm, and this increase in autumn takes place obviously at the expense of lipid storage. 4. 4. The differences in glycogen values between two temperature regimes during acclimation were mostly non-significant, while the transportation from field to the laboratory caused a significant decline in liver and muscle glycogen values in summer frogs, but only in muscle glycogen values in winter frogs.

Contrast sensitivity after resolution of central serous retinopathy

The contrast sensitivity of 21 patients was measured using TV equipment (Wavetek 143 function generator and Sony PVM90CE video monitor) and the Vistech test 6–15 years after the acute stage of central serous retinopathy. In the majority of cases contrast sensitivity was lower in the affected eye. The difference between the affected and the fellow eye was statistically significant at 1 and 6 cycles/degree (c/d) but not at 19 c/d. In 13/21 cases (62%) the results of the Vistech test were consistent with those of the TV test. Contrast sensitivity did not correlate with the duration of the disease or with the ultimate clinical picture of the macula. At 6 c/d there was a statistically significant correlation between visual acuity and contrast sensitivity. If the visual acuity was less than 1.0, contrast sensitivity was decreased, but decreased contrast sensitivity was also observed in four eyes with normal visual acuity, indicating that the level of visual deficit may not be established by measurement of visual acuity alone.

The effect of jogging on visual field indices.

Abstract. The Humphrey 30–2 visual field was examined 9 times before and after an 8–km jog in one subject, whose contrast sensitivity had been found to improve after jogging. The mean deviation improved statistically significantly suggesting better sensitivity of the visual system after jogging. Our results suggest that in some individuals physical exercise influences the factors which lie behind the visual field long‐term fluctuation.

Jogging and contrast sensitivity.

Abstract. Threshold contrast sensitivity was measured using sinusoidal gratings with the method of increasing contrast both before and after jogging in fresh air. The mean contrast sensitivity of 11 subjects was higher after jogging at all three spatial frequencies studied (1, 6 and 19 c/deg). The differences were statistically significant. The effect of jogging was subject to individual variation, some ‘unstable’ subjects responding strongly and some ‘stable’ subjects showing no change at all. Two ‘unstable’ subjects were tested several times, and their strong response proved to be repeatable.

Permanent results of pleoptic treatment

Abstract The value of pleoptic treatment was assessed by a long‐term follow‐up of patients treated 15–22 years ago, employing a questionnaire sent to 232 patients and a clinical examination of a sample of 44 of these. Answers were received from 157 persons with different occupations and educational levels who were fairly representative of the population of Northern Finland as a whole. The treatment was considered beneficial by 62% of these. The primary improvement in the mean visual acuity (VA) from 0.33 to 0.86 among the 44 persons examined proved to be partly transitory, the final mean value being 0.61. The poorest results were found in the combined stabismic and anisometropic amblyopia group. The final VA correlated positively with the initial VA and negatively with age at the time of treatment. Binocular single vision improved the prognosis. Altogether 1/4 of the patients achieved a VA of 1.0 or better, about one half experienced no permanent increase in VA and the remainder were distributed evenly between these two extremes.

Correlations between visual acuity, grating acuity and contrast sensitivity in amblyopia

Abstract In order to obtain a large set of data to analyse correlations between different measures of vision in amblyopia, we pooled the information on all 114 amblyopic patients contained in our earlier series (49 strabismic, 28 anisometropic and 37 combined strabismic/anisometropic children).

EFFECT OF VEHICLE ON PILOCARPINE‐INDUCED OCULAR HYPOTENSION

The effect of 1.4% polyvinyl alcohol and castor oil vehicles on pilocarpine‐induced hypotension was studied in 50 patients with open‐angle glaucoma. Diurnal tension curves showed that the mean intraocular pressure was lower and the maximum diurnal variation smaller during the treatment with oily drops of 2% and 4% pilocarpine instilled 2–3 times daily than when 2% and 4% pilocarpine in polyvinyl alcohol was instilled 3–4 times daily. The differences were statistically significant. In long‐term treatment no marked pilocarpine tolerance developed in cases treated with oily drops of pilocarpine. It is concluded that in the treatment of patients with open‐angle glaucoma, the hypotensive effect of pilocarpine in an oily vehicle instilled 2–3 times daily is greater and more even than that of pilocarpine of corresponding strength in polyvinyl alcohol administered 3–4 times daily.