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Evolution of optic disc oedema in raised intracranial pressure. Experimental study
The Influence of Epinephrine, Tolazoline (Priscoline) and Corticosteroids through Capillaries at the Cornea1 Limbus in Man B. JIEISSNER
11. brEDBURG.
AXD
li.
MIE,
on the Blood Flovv
~ii~.wkt~llf
The influence of various locally applied drugs was studied by means of fluorescein angiography of capillaries at the cornea1 limbus. Epinephrine caused a definite reduction of blood flow and t,olazoline produced hyperaemia. Dexamethasone had a slight inhibitory effect on the blood flow. In ocular inflammat,ion due to cornea1 grafting (rejection reactions) the influence of local and systemic corticosteroid treatment on limbal capillaries was also demonstrated. In these cases the question arises as to whether the reduction of hyperaemia is a primary effect on the vessel3 or nlerely secondary to the reduction of the innnunologirnl reaction.
Photocoagulation
and the Electroretinogram
Retinal function can objectively be assessed by means of the electroretinogram (EM:). Such assessment is difficult in disturbances of the retinal circulation, when photocoagulat,ion has been carried out, since the influence of the coagulation itself on the ERG is not exactly known. \Ve approached this problem by examining the ER,(+ in a group of rabbits before and after coagulation. comparing the decrease in height of the electrical responses with the extent anti localization of the coagulated area. The decrease in height of the responses after phot,ocoagulation applied in a checkerboard pattern is more than one would expect considering the ophthalmoscopic aspect Histologically, it, appeared that this discrepancy may be ascribed to a degeneration of the retina between the coagulations. After serried coagulations eliminating less than 30°, of the retinal surface, the ERG is reduced proportionally to the destroyed area. When more t.hsn 3W,, of the retinal surface is eliminatcti. the decrease in response becomes greater than t,he enlargement of t,hc coagulated area. C’ongulation of the retinal periphery will be performed in order to investigate whether these findings are to be attributed to a relatively high contribrrtion of the retinal prriphery to the ER( I.
Retinal Blood Flow after Experimental 11. \\'.
HILL
.\XD
S. POUYG.
Photocoagulation
London
Photocoagulation has been applied by xenon arc, to close the capillary bed in the lower temporal quadrant of one eye in four cats, after preliminary tine-angiography. Three weeks later the flo\\ rate has been reassessed and the animal sacrificed to allow post mortem examinat’ion of the injrctctl flattened retina. Flow in the major arteriole supplying the coagulated area was reduced in proportion to the extent of the coagulated area. Flow in the branches supplying t.he coagulated area was greatly reduced, but that into branches supplying untreated retina depended upon the flow rate of t.bc parent major arteriole. Reduction to 75O ;1 pretreatment vallle was accompanied b,v an increase. &Au&ion to 5Oo,, by a decrease in branch vessel flolv. The exnlanation of this behaviour is likelv to lie with the rhcologv U” of the blood. The results roaltl be if importance in clinical phot,ocoagnlat’ion and in the pathogcnesis of occlusive PRSWI:II rctinopathp. Y
Evolution of Optic Disc Oedema in Raised Intracranial S. S. HAYREH
AND
31. S. HAYREH,
Ioun
City,
Pressure. Experimental
Study
U.S.A.
Progressively growing intracranial space-taking lesions \vero simulated in 33 monkeys by balloons introduced into the subarachnoid space. The fundi were examined ophthalmoscopically, bv stereoscopic colour fundus photography and by fluoresccin angiography serially to’ study the evolut.ion and resolution of optic oedema (ODO) and the patt.erns revealed by each technique at different stages of ODO. These studies revealed that ODO first appears at the lower pole, then the upper pole. then the nasal part and lastly the temporal part of the disc, and that the severity of the swelling generally follows suit: most marked at t,he lower pole, etc. (I’ < 0~005). Except in very early ODO, striation of the nerve fibres (best seen in the peripapillary retina) was a constant ophthalmoscopic finding and seems to represent axoplasmic flow stasis.
axoplasmic flow studies in these eyes. The early swclliag of’ t!w (list, in OLN) is tl~lcb IO a~onill swellinn in the ootic: disc. That is whv the atrot)hic r>art, ofthc optic clisl, tlow not, tlcvc.lor) ()I)(). I II this sturdy stereoicopic colour photoiraphy was fo&l to IJP thv &A nlcthot! ot’tletwtitlg (:arIy ( )!)( ). Twenty-four hours or even less of raised intracranial prwsuw (‘an ca~lsc 0110 (thollph tlwrca is very wdc variation). R~esolut~ion of ODO oc,l,ruwd in a pattcru rewrw to t Il;tt 01’ tsrolllt iorb.
Glycosaminoglycans
in the Conjunctiva
in Hereditary
Diabetic Mice
There are parallel alterat,ions to the ult,rastruoturc of the capillary ba.scment mcmbranc~ and of the metabolism of the ext,racellular matrix in the conjunctira of hereditary diabetic mice (l
Exchange of Technetium
across the Conjunctiva
T. SEYRXNSEN AND F. TAAGEH~J
JENSEN.
IIelsi,llci
Using a gamma camera coupled with a comput,er and a tape unit t.he exchange of pcrtrchnrtatc (Tc99m) across the conjunctiva was determined by the “region of interest” technique on human subiects. The method was applied so that the “fraciional turnover rate“ of technetium represented t,hetransport to the general circulation. In Datients with their lacrimal sacs removed a fractional turnover rate of 0.022 min.-l was found. In paiients with inflamed and hyperaemic conjunctiva due to chronic dacryocystit,is the transport to the blood was found to be twice as big. In some normal humans bhe technetium did not enter the nasolacrimal duct in the 15 min measuring time. Under these circumstances a fractional turnover rate of only 0.014 min-’ was found representing the transport of technetium across the conjunctivn and the lacrimal sac. Blood samples mere taken from several of these patients and a correlation could be found bet\\ een the radioactivity in the blood and the fractional turnover rate. By taking blood samples serinlly at t,hree minute intervals the fractional turnover rate WIS found bo tally with t.he rat.e of acfi\.ify increase in the blood.
Problems of Quantitative H. VALENZUELA-HAAG,
Correlation H. G. TRIER,K.
of Echographic DETZER,
and Histologic
R. REUTER,
Bonn
Findings ANP D. DECKER,S~U~~~~~~
Many authors have tried to correlate echographical and histological findings of defined eye tissues. In order to describe the echogram they have utilized the reduced information which can be extracted from a conveutional A-mode echogram by visual means. For a more complete echogram evaluation, the ratio frequency echo signal and signal processing by machine are necessary. It is known also that it is difficult to describe histologic findings in terms of quantitative parameters. So far comparative reports contain only sporadic quantitative data about the histological elements in relation to the area of the preparation studied. A representative analogous to the three-dimensional histologic description of the structures examined, as can be obtained from twodimensional histological preparations by means of stereologic studies, i.e. through the application
11. brEDBURG.
AXD
li.
MIE,
on the Blood Flovv
~ii~.wkt~llf
The influence of various locally applied drugs was studied by means of fluorescein angiography of capillaries at the cornea1 limbus. Epinephrine caused a definite reduction of blood flow and t,olazoline produced hyperaemia. Dexamethasone had a slight inhibitory effect on the blood flow. In ocular inflammat,ion due to cornea1 grafting (rejection reactions) the influence of local and systemic corticosteroid treatment on limbal capillaries was also demonstrated. In these cases the question arises as to whether the reduction of hyperaemia is a primary effect on the vessel3 or nlerely secondary to the reduction of the innnunologirnl reaction.
Photocoagulation
and the Electroretinogram
Retinal function can objectively be assessed by means of the electroretinogram (EM:). Such assessment is difficult in disturbances of the retinal circulation, when photocoagulat,ion has been carried out, since the influence of the coagulation itself on the ERG is not exactly known. \Ve approached this problem by examining the ER,(+ in a group of rabbits before and after coagulation. comparing the decrease in height of the electrical responses with the extent anti localization of the coagulated area. The decrease in height of the responses after phot,ocoagulation applied in a checkerboard pattern is more than one would expect considering the ophthalmoscopic aspect Histologically, it, appeared that this discrepancy may be ascribed to a degeneration of the retina between the coagulations. After serried coagulations eliminating less than 30°, of the retinal surface, the ERG is reduced proportionally to the destroyed area. When more t.hsn 3W,, of the retinal surface is eliminatcti. the decrease in response becomes greater than t,he enlargement of t,hc coagulated area. C’ongulation of the retinal periphery will be performed in order to investigate whether these findings are to be attributed to a relatively high contribrrtion of the retinal prriphery to the ER( I.
Retinal Blood Flow after Experimental 11. \\'.
HILL
.\XD
S. POUYG.
Photocoagulation
London
Photocoagulation has been applied by xenon arc, to close the capillary bed in the lower temporal quadrant of one eye in four cats, after preliminary tine-angiography. Three weeks later the flo\\ rate has been reassessed and the animal sacrificed to allow post mortem examinat’ion of the injrctctl flattened retina. Flow in the major arteriole supplying the coagulated area was reduced in proportion to the extent of the coagulated area. Flow in the branches supplying t.he coagulated area was greatly reduced, but that into branches supplying untreated retina depended upon the flow rate of t.bc parent major arteriole. Reduction to 75O ;1 pretreatment vallle was accompanied b,v an increase. &Au&ion to 5Oo,, by a decrease in branch vessel flolv. The exnlanation of this behaviour is likelv to lie with the rhcologv U” of the blood. The results roaltl be if importance in clinical phot,ocoagnlat’ion and in the pathogcnesis of occlusive PRSWI:II rctinopathp. Y
Evolution of Optic Disc Oedema in Raised Intracranial S. S. HAYREH
AND
31. S. HAYREH,
Ioun
City,
Pressure. Experimental
Study
U.S.A.
Progressively growing intracranial space-taking lesions \vero simulated in 33 monkeys by balloons introduced into the subarachnoid space. The fundi were examined ophthalmoscopically, bv stereoscopic colour fundus photography and by fluoresccin angiography serially to’ study the evolut.ion and resolution of optic oedema (ODO) and the patt.erns revealed by each technique at different stages of ODO. These studies revealed that ODO first appears at the lower pole, then the upper pole. then the nasal part and lastly the temporal part of the disc, and that the severity of the swelling generally follows suit: most marked at t,he lower pole, etc. (I’ < 0~005). Except in very early ODO, striation of the nerve fibres (best seen in the peripapillary retina) was a constant ophthalmoscopic finding and seems to represent axoplasmic flow stasis.
axoplasmic flow studies in these eyes. The early swclliag of’ t!w (list, in OLN) is tl~lcb IO a~onill swellinn in the ootic: disc. That is whv the atrot)hic r>art, ofthc optic clisl, tlow not, tlcvc.lor) ()I)(). I II this sturdy stereoicopic colour photoiraphy was fo&l to IJP thv &A nlcthot! ot’tletwtitlg (:arIy ( )!)( ). Twenty-four hours or even less of raised intracranial prwsuw (‘an ca~lsc 0110 (thollph tlwrca is very wdc variation). R~esolut~ion of ODO oc,l,ruwd in a pattcru rewrw to t Il;tt 01’ tsrolllt iorb.
Glycosaminoglycans
in the Conjunctiva
in Hereditary
Diabetic Mice
There are parallel alterat,ions to the ult,rastruoturc of the capillary ba.scment mcmbranc~ and of the metabolism of the ext,racellular matrix in the conjunctira of hereditary diabetic mice (l
Exchange of Technetium
across the Conjunctiva
T. SEYRXNSEN AND F. TAAGEH~J
JENSEN.
IIelsi,llci
Using a gamma camera coupled with a comput,er and a tape unit t.he exchange of pcrtrchnrtatc (Tc99m) across the conjunctiva was determined by the “region of interest” technique on human subiects. The method was applied so that the “fraciional turnover rate“ of technetium represented t,hetransport to the general circulation. In Datients with their lacrimal sacs removed a fractional turnover rate of 0.022 min.-l was found. In paiients with inflamed and hyperaemic conjunctiva due to chronic dacryocystit,is the transport to the blood was found to be twice as big. In some normal humans bhe technetium did not enter the nasolacrimal duct in the 15 min measuring time. Under these circumstances a fractional turnover rate of only 0.014 min-’ was found representing the transport of technetium across the conjunctivn and the lacrimal sac. Blood samples mere taken from several of these patients and a correlation could be found bet\\ een the radioactivity in the blood and the fractional turnover rate. By taking blood samples serinlly at t,hree minute intervals the fractional turnover rate WIS found bo tally with t.he rat.e of acfi\.ify increase in the blood.
Problems of Quantitative H. VALENZUELA-HAAG,
Correlation H. G. TRIER,K.
of Echographic DETZER,
and Histologic
R. REUTER,
Bonn
Findings ANP D. DECKER,S~U~~~~~~
Many authors have tried to correlate echographical and histological findings of defined eye tissues. In order to describe the echogram they have utilized the reduced information which can be extracted from a conveutional A-mode echogram by visual means. For a more complete echogram evaluation, the ratio frequency echo signal and signal processing by machine are necessary. It is known also that it is difficult to describe histologic findings in terms of quantitative parameters. So far comparative reports contain only sporadic quantitative data about the histological elements in relation to the area of the preparation studied. A representative analogous to the three-dimensional histologic description of the structures examined, as can be obtained from twodimensional histological preparations by means of stereologic studies, i.e. through the application