DEPARTMENTS OF OPHTHALMOLOGY AND PATHOLOGY AND DIABETIC UNIT, HADASSAtt UNIVERSITY HOSPITAL AND THE HEBREW UNIVERSYI~f, HADASSAH MEDICAL SCHOOL, JERUSALEM A CORRELATIVE STUDY ON T H E OCCURRENCE OF R E T I N O P A T H Y AND N E P H R O P A T H Y IN SUCROSE-FED DIABETIC RATS LUTZA YANKO
ELIEZER ]~OSENMANN
AHARON M. Cotton
The correlation between the occurrence of glomerulosclerosis and diabetic retinopathy is not yet well defined. Clinical studies and histopathologic correlations have shown that diabetic retinal changes are often present in diabetics with no renal involvement, whereas intercapillary glomerulosderosis is found but rarely in the absence of diabetic retinopathy 1. ~, 29. Likewise, many investigators have pointed out that the frequency of glomerulosclerosis is directly related to the increasing severity of retinopathy 20.2s. There are, however, reports on the occurrence of diabetic glomerulosclerosis in cases in which both ophthalmoscopic and histopathologic examination of the retina failed to reveal characteristic diabetic vascular changes ~. During the past several years, we have been able to develop a diabetic rat by genetic selection and a high sucrose diet ~3. The diabetic syndrome in this animal has many common characteristics with the adult onset of human diabetes mellitus: a) genetic predisposition la; b) interaction between genetic and dietary factors for the expression of the diabetic syndrome x3; c) characteristic patterns of diabetic enzymatic activity 1.,; d) retinal ~0 and renal a~ diabetic microangiopathy. In view of this close resemblance we studied the correlation between the occurrence of diabetic retinopathy and diabetic nephropathy in our model, with the aim of clarifying this problem by inference in man. MATERIAL AND METHODS One hundred thirty nine rats were used. Their siblings, which were fed starch,
did not develop diabetes ,a, and were used as controls.
At various times foliowing the beginning of sucrose feeding, the animals were anaesthetized with ether and bled through the aorta. Both eyes and kidneys were removed immediately after death and fLxedin 4% neutral formalin. Following fixation, one eye of each animal was opened coronally and the posterior pole of the globe divided into t~ee portions around the optic disc. The retina was removed from each portion v.dth a thin spatula under normal saline and was digested. After rinsing in distilled water, the retina was transferred immediately to 3% pepsin in 1% hydrochloric acid, incubated at 37 °C for 30 rain, then washed in distilled water and thereafter subjected to 3% Key-words: Diabetic nephrop~thy; Diabetic retinopa:by: Genetic selection; Ra~.: 5zzcrosc.
Received: October 2t, 1974. Acra diabet lar. 72, 52, 1975. 52
L, YANK0, E. ROSENx%iAI~, A. lk'I. COHEN
trypsin digestion at 37 °C for 6%90 rain 3. The treated retina was mounted on a slide, dried and stained with periodic-acid Schi.ff(PAS) and hemamxylin. Each preparation was examined under the light microscope with special reference to capillary microaneurysms, capillary diameter and its regularity, endothelial- and mural-call nuclei and the relationship of the two cell types to one another. For histological examination specimens of the kidneys were embedded in parafEn and sections 3 to 4 D thick were stained with hematoxylin and eosin, PAS, Ritter-Olsen method (PAS-colloidaliron), Masson's trichrome and the silver methenamine method. Frozen sections were stained with Sudan iII for neutral lipids. RESULTS The &aracterisfics and the incidence of retinal and renal vascular lesions in 139 sucrose-fed diabetic rats in which both kidney and retina were examined are shown in tab. 1. Compared to the retinae of the control animals (fig. 1), in the retinae of 44 (31%) of 139 sucrose-fed diabetic rats, a marked diffuse diminution of either mural or endothelial ceils or of both types was observed. In the latter, the vessels were recognizable only by basement membrane sheaths (fig. 2). Alongside the diminution of mural and/or endothelial cells, capiIlary strands of approximately one-third the size of normal capillaries (~g. 3) were fomq_d in 37 (26,%) of 139 sucrose-fed diabetic rats. Microaneurysms (fig. 4) were present in 12 (9%) sucrose-fed rats. When compared with the control animals (fig. 5) the kidneys of 32 (23%) of the 139 sucrose-fed diabetic rats exhibited a diffuse intercapillary glomerulosderosis (fig. 6). In several instances, exudative or lipohyaline glomerutar lesions were present (fig. 7). In the controls neither renal nor retinal changes were observed but for a slight diminution of capillary ceils in the periphery of the retina in a number of animals. The correlation between the inddence of retinal and renal vascular lesions in the sucrose-fed diabetic rats is shown in tab. 2. Both retinal and renal microangiopathy were present in 13,% of the diabetic animals. Retinal
duration of diabetes (months) 2-6 (22)
(72)
13-18 (45)
tot~ (I39)
25 23 9
15 13 3
44 (31%) 37 (26%) 12 ( 9 % )
t6
8
32 (23~)
7-12
retinal capillary changes diminution of cells strand formation microaneurysm renal changes diffuse glomerulosclerosis
8
I - Characteristics and distribution of reti~.aI and renal vascular lesions in 139 sucrose-fed diabetics rats.
Table
53
DIABETIC A N G I O P A T H Y
IN PATS
duration of diabetes (months) pathologicaI changes 3-6 (22)
7-12 (72)
13-18 (45)
total (i39)
17 24
11 24
28 2O
4 9
14 10
4 9
18 13
retina aIone no. of animals % kidney alone no. of animals 9b
4 18
both retina and Mdney no. of animals %
4 18
10 14
Table 2 - Correlation of occurrence of retinN and renal vascular lesions in 139 sucrose-fed diabetic rats.
microangiopathy with normal glomeruli was present in 20%, while glomerular disease with normal retina was observed in 10% of these animals. No correlation was found between blood glucose levels and occurrence of pathological findings in the retina and/or kidney (tab. 3). DISCUSSION Renal changes characterized by diffuse intercapillary glomerulosclerosis have been described in experimental diabetic rats a2, an, dogs ~ and monkeys 21, and in spontaneously diabetic Chinese hamsters a0, KK mice 9, oh~oh mice 2~ and in the Geneva colony of spiny mice .~2.Numerous laboratories have studied the retinae in experimental diabetes in the rat sv, a~, rabbit ~' 16, spontaneously diabetic Chinese hamster 28. as, and sand rat ( P s a m m o m y s obesus) 2a. However, none of these animals exhibited significant microvascular retinal lesions and, therefore, none of them is satisfactory as an experimental model for the study of diabetic retinopathy. Retina1 microangiopathy, comparable to that of human diabetes, has been described o~Jy in a few spontaneously diabetic dogs a4, a6 ~nd in a limited number of dogs, 5-7 years after induction of diabetes by bovine growth hormone or by alloxan is. 24 The earliest, and apparently the mildest, capillary lesions which occur in the retina of diabetics include the loss o~ intramural cells (pericytes), loss o~ endothdial cells, or loss of both. In the latter case, empty basement membrane sheaths and often capillary strands of approximately one-third the size of normal capillaries are found in the digested flat retina 7. Alongside these degenerative changes, a variable number of microaneurysms are found in the a~ected retinae. 54
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F.,g. I - Digested fiat retina of starch-fed rat (control) showing normai celtuIarity of capillaries. PAS and hematoxylin, X 420.
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>,Milano, 1971; Acta diabet. Sat. g (Suppl. 1), 263, 1971. 8) BLooDwol~ J. M. B. Jr., ENC~aAN R. L., ANDEItSONP. J.: blicroangiopathy in the Experimentally Diabetic Animal - In: CAMEaIN>DLvaLOSR. A., COLE H. S. (Eds): Vascular and Neurological Changes in Early Diabetes. Academic Press, New York, 1973; p. 245. 9) CAME~V..INI-D~.vaLOSR. A., OPPER~IANNW., MITTL R., EttRENREICHT.: Studies of Vascular and Other Lesions in KK Mice - Diabemlogia 6, 324, !970. 10) COHEN A. M., MmH.~J.SO.~ I. C., YAN~:OL.: Retinopathy in Rats with Disturbed Carbohydrate Metabolism Following a High Sucrose Diet. I. Vascular Changes Amer. }. Ophthal. 73, 863, 1972. 11) COHENA. M., ROSENMANNE.: Diffuse Intercapillary Glomeru!osclerosis in SucroseFed Rats - Diabetologia 7, 25, 1971. 64
L. YANKO) E. ROSENNIANN~ A. M. COHEN
12) COHENA. M., TEITELBAUMA., BRIJ,I,EI~ S., ROSENMANNE., YA~'~o L., Su~xilt E.: Role of Diet and Genetics in the Development of Angiopatby in Diabetes - In: Gr,ETEN H., LEVlNE R., PF~I~'EERE. F., RENOLDA. E. (Eds): Lipid Metabolism, Obesity and Diabetes Mellims: Impact upon Atherosclerosis. Georg Thieme Verlag, Stuttgart, 1974; p. 117. 13) COHEN A. M., TEtTELBAUM A., SALI~EI~IK R.: Genetics and Diet as Factors ha Development of Diabetes Mellims - MetaboLism 21, 235, 1972. 14) DAY R.: Problem of Diabetic Retinopathy - Sth. med. J. (Bgham, Ata.) 44, 549, 1951. 15) ENGEm',nANR. L., BI,ooI~WOI~rl4J. M. B. Jr.: Experimental Diabetic Retinopathy in Dogs - Arch. Ophthai. 73, 205, 1965. 16) ENGEI~MaNR. L., MEYER R. K., BU~SSELEa J. A.: Effect of Alloxan Diabetes and Steroid Hypertension on Retinal Vasculature - Amer. J. Ophtbal. 58, 965, 1964. 17) E~GLESONG.: Studies in Diabetes Mellitus - Acta Paediat. (Uppsala) 43 (Suppl. 97), t16, 1954. 18) FEDERMANJ. L., GERRITSENG. C.: The Retinal Vasculature of the Chinese Hamster: a Preliminary Study - Diabetologia 6, 186, 1970. 19) FoGI,Ia V. G., MANClNI R. E., Ct~r,.DEZaA. F.: Glomerular Lesions in the Diabetic Rat - A,M,A. Arch. Path. 50, 75, 1950. 20) GELLMaN D. D., PIRANI C. L., SOOTHIL~ J. F., MI:E~eC~E R. C., KAr,x R. M.: Diabetic Nephropathy: a Clinical and Pathologic Study Based on Renal Biopsies Medicine (Baltimore) 38, 321, 1959, 21) GIBBS G, E., WILSON R. B., GII~Fom~H. Jr.: Glomeru]osclerosis in the Long-Term Alloxan Diabetic Monkey - Diabetes 15, 258, 1966. 22) GONET A. E., S:rAUrFaCHZRW., PICTET R., R~NOLI) A. E.: Obesiv] and Diabetes Mellitus with Stricldng Congenital Hyperptasia of the Islets of Langerhans in Spiny Mice (Acomys cahirinus). I. Histological Findings and Preliminary Metabolic Observations - DiabetoloNa t, 162, 1965. 23) Iq_~CKeLD. B., SCHMIDT-NIELSENK., HainES H. B., MIKAT E.: Diabetes Mellitus in the Sand rat (Psammomys obesus). Pa~hologic Studies - Lab. Invest. I4, 200, 1965. 24) HAUSLERH. R., SI~AYT. M,, CAMPBEI,L J.: Retinopathy in a Dog Following Diabetes Induced by Growth Hormone - Diabetes 13, 122, 1964. 25) H_ELLMa~ZB.: Studies in Obese-Hyperglycemic Mice - Arm. N, Y. Acad. Sci. I3t, 541, 1965. 26) HotqeY G. E., P~rsE-DaWES J., Ro~exTs D. M.: A Survey o{ Nephropathy in Young Diabetics - Quart. J. Med. 31,473, 1962. 27) K.t~:scm,r~t R., LEO~'0LD I. H.: Retinal Changes in the Alloxan Diabetic Rat Maintained on a High Fat Diet - Arch. Ophthal. 64, 681, 1960. 28) KoeN~lJv T.: Studies in Diabetic Rednopathy. An Investigation of 1,000 Cases of Diabetes - Acta reed. scand. 153, 81, 1955. 29) K~l~t.~'~ H., M~I4NEI~ H., L.~NC,Ee E.: Retinopathie und GIomerutosklerose bei Diabetikern - Med. Klin. 64, 747, 1969. 30) LaWE J. E.: Renal Changes in Hamsters with Hereditary Diabetes Mellitus - Arch. Path. 73, 86, 1962. 31) L~V~E R., LAZZAI~I~I-Ro~ER~SO~A. J., FOGLt~ V. G., SI~6E~ J.: The Retina in Experimental Diabetic Rats - Arch. Ophtha!. 70, 253, 1963. 32) M.~'~" G. U., G o ~ a ~ J. W., A~aMs L.: The Renal Lesions Associated with Experimental Diabetes in the Rat - Amer. J. Pathot. 27, 857, 1951. 33) Ol~s~covH., S~EEN OLSEN T., NIELSEN K., RAFAELSENO. J., LUNDB,~KK.: Kidney Lesions in the Rats wire Severe Long-Term Alloxan Diabetes. I. Influence of Age, Altoxan Damage and Insulin Administration - Diabetologia I, 172, 1965. 34) PATZA., B~m~ow J. W., MAUMENEZA. E., Cox J.: Studies on Diabetic Retinopathy and Nephropathy in Spontataeous Canine Diabetes - Diabetes 14, 700, t965. 35) POMETT,~D., TA:roN J., P,~ES S. B., KUWA~ARAT.: Retinal Vascular Change in the Chinese Hamster - Diabetologia 2, 215, 1966. 36) SrBAY T. M., HAUSLE:~H. R.: Eye Findings {n Two Spontaaeously Diabetic Related Dogs - Amer. J, Ophthal. 63, 289, 1967.
Re~iaests /or t'eprints shoalld be Mdressed to: LUTZA YANKO
Department o/ Ophthalmology Hadassah University Hospital ]erusMem o lsrae! 65
ELIEZER ]~OSENMANN
AHARON M. Cotton
The correlation between the occurrence of glomerulosclerosis and diabetic retinopathy is not yet well defined. Clinical studies and histopathologic correlations have shown that diabetic retinal changes are often present in diabetics with no renal involvement, whereas intercapillary glomerulosderosis is found but rarely in the absence of diabetic retinopathy 1. ~, 29. Likewise, many investigators have pointed out that the frequency of glomerulosclerosis is directly related to the increasing severity of retinopathy 20.2s. There are, however, reports on the occurrence of diabetic glomerulosclerosis in cases in which both ophthalmoscopic and histopathologic examination of the retina failed to reveal characteristic diabetic vascular changes ~. During the past several years, we have been able to develop a diabetic rat by genetic selection and a high sucrose diet ~3. The diabetic syndrome in this animal has many common characteristics with the adult onset of human diabetes mellitus: a) genetic predisposition la; b) interaction between genetic and dietary factors for the expression of the diabetic syndrome x3; c) characteristic patterns of diabetic enzymatic activity 1.,; d) retinal ~0 and renal a~ diabetic microangiopathy. In view of this close resemblance we studied the correlation between the occurrence of diabetic retinopathy and diabetic nephropathy in our model, with the aim of clarifying this problem by inference in man. MATERIAL AND METHODS One hundred thirty nine rats were used. Their siblings, which were fed starch,
did not develop diabetes ,a, and were used as controls.
At various times foliowing the beginning of sucrose feeding, the animals were anaesthetized with ether and bled through the aorta. Both eyes and kidneys were removed immediately after death and fLxedin 4% neutral formalin. Following fixation, one eye of each animal was opened coronally and the posterior pole of the globe divided into t~ee portions around the optic disc. The retina was removed from each portion v.dth a thin spatula under normal saline and was digested. After rinsing in distilled water, the retina was transferred immediately to 3% pepsin in 1% hydrochloric acid, incubated at 37 °C for 30 rain, then washed in distilled water and thereafter subjected to 3% Key-words: Diabetic nephrop~thy; Diabetic retinopa:by: Genetic selection; Ra~.: 5zzcrosc.
Received: October 2t, 1974. Acra diabet lar. 72, 52, 1975. 52
L, YANK0, E. ROSENx%iAI~, A. lk'I. COHEN
trypsin digestion at 37 °C for 6%90 rain 3. The treated retina was mounted on a slide, dried and stained with periodic-acid Schi.ff(PAS) and hemamxylin. Each preparation was examined under the light microscope with special reference to capillary microaneurysms, capillary diameter and its regularity, endothelial- and mural-call nuclei and the relationship of the two cell types to one another. For histological examination specimens of the kidneys were embedded in parafEn and sections 3 to 4 D thick were stained with hematoxylin and eosin, PAS, Ritter-Olsen method (PAS-colloidaliron), Masson's trichrome and the silver methenamine method. Frozen sections were stained with Sudan iII for neutral lipids. RESULTS The &aracterisfics and the incidence of retinal and renal vascular lesions in 139 sucrose-fed diabetic rats in which both kidney and retina were examined are shown in tab. 1. Compared to the retinae of the control animals (fig. 1), in the retinae of 44 (31%) of 139 sucrose-fed diabetic rats, a marked diffuse diminution of either mural or endothelial ceils or of both types was observed. In the latter, the vessels were recognizable only by basement membrane sheaths (fig. 2). Alongside the diminution of mural and/or endothelial cells, capiIlary strands of approximately one-third the size of normal capillaries (~g. 3) were fomq_d in 37 (26,%) of 139 sucrose-fed diabetic rats. Microaneurysms (fig. 4) were present in 12 (9%) sucrose-fed rats. When compared with the control animals (fig. 5) the kidneys of 32 (23%) of the 139 sucrose-fed diabetic rats exhibited a diffuse intercapillary glomerulosderosis (fig. 6). In several instances, exudative or lipohyaline glomerutar lesions were present (fig. 7). In the controls neither renal nor retinal changes were observed but for a slight diminution of capillary ceils in the periphery of the retina in a number of animals. The correlation between the inddence of retinal and renal vascular lesions in the sucrose-fed diabetic rats is shown in tab. 2. Both retinal and renal microangiopathy were present in 13,% of the diabetic animals. Retinal
duration of diabetes (months) 2-6 (22)
(72)
13-18 (45)
tot~ (I39)
25 23 9
15 13 3
44 (31%) 37 (26%) 12 ( 9 % )
t6
8
32 (23~)
7-12
retinal capillary changes diminution of cells strand formation microaneurysm renal changes diffuse glomerulosclerosis
8
I - Characteristics and distribution of reti~.aI and renal vascular lesions in 139 sucrose-fed diabetics rats.
Table
53
DIABETIC A N G I O P A T H Y
IN PATS
duration of diabetes (months) pathologicaI changes 3-6 (22)
7-12 (72)
13-18 (45)
total (i39)
17 24
11 24
28 2O
4 9
14 10
4 9
18 13
retina aIone no. of animals % kidney alone no. of animals 9b
4 18
both retina and Mdney no. of animals %
4 18
10 14
Table 2 - Correlation of occurrence of retinN and renal vascular lesions in 139 sucrose-fed diabetic rats.
microangiopathy with normal glomeruli was present in 20%, while glomerular disease with normal retina was observed in 10% of these animals. No correlation was found between blood glucose levels and occurrence of pathological findings in the retina and/or kidney (tab. 3). DISCUSSION Renal changes characterized by diffuse intercapillary glomerulosclerosis have been described in experimental diabetic rats a2, an, dogs ~ and monkeys 21, and in spontaneously diabetic Chinese hamsters a0, KK mice 9, oh~oh mice 2~ and in the Geneva colony of spiny mice .~2.Numerous laboratories have studied the retinae in experimental diabetes in the rat sv, a~, rabbit ~' 16, spontaneously diabetic Chinese hamster 28. as, and sand rat ( P s a m m o m y s obesus) 2a. However, none of these animals exhibited significant microvascular retinal lesions and, therefore, none of them is satisfactory as an experimental model for the study of diabetic retinopathy. Retina1 microangiopathy, comparable to that of human diabetes, has been described o~Jy in a few spontaneously diabetic dogs a4, a6 ~nd in a limited number of dogs, 5-7 years after induction of diabetes by bovine growth hormone or by alloxan is. 24 The earliest, and apparently the mildest, capillary lesions which occur in the retina of diabetics include the loss o~ intramural cells (pericytes), loss o~ endothdial cells, or loss of both. In the latter case, empty basement membrane sheaths and often capillary strands of approximately one-third the size of normal capillaries are found in the digested flat retina 7. Alongside these degenerative changes, a variable number of microaneurysms are found in the a~ected retinae. 54
i •
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r
- 5£.
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(
_,.; X .X
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F.,g. I - Digested fiat retina of starch-fed rat (control) showing normai celtuIarity of capillaries. PAS and hematoxylin, X 420.
. .:
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~
~:~..r,.. ' =. • .~ ~:>~..
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>,Milano, 1971; Acta diabet. Sat. g (Suppl. 1), 263, 1971. 8) BLooDwol~ J. M. B. Jr., ENC~aAN R. L., ANDEItSONP. J.: blicroangiopathy in the Experimentally Diabetic Animal - In: CAMEaIN>DLvaLOSR. A., COLE H. S. (Eds): Vascular and Neurological Changes in Early Diabetes. Academic Press, New York, 1973; p. 245. 9) CAME~V..INI-D~.vaLOSR. A., OPPER~IANNW., MITTL R., EttRENREICHT.: Studies of Vascular and Other Lesions in KK Mice - Diabemlogia 6, 324, !970. 10) COHEN A. M., MmH.~J.SO.~ I. C., YAN~:OL.: Retinopathy in Rats with Disturbed Carbohydrate Metabolism Following a High Sucrose Diet. I. Vascular Changes Amer. }. Ophthal. 73, 863, 1972. 11) COHENA. M., ROSENMANNE.: Diffuse Intercapillary Glomeru!osclerosis in SucroseFed Rats - Diabetologia 7, 25, 1971. 64
L. YANKO) E. ROSENNIANN~ A. M. COHEN
12) COHENA. M., TEITELBAUMA., BRIJ,I,EI~ S., ROSENMANNE., YA~'~o L., Su~xilt E.: Role of Diet and Genetics in the Development of Angiopatby in Diabetes - In: Gr,ETEN H., LEVlNE R., PF~I~'EERE. F., RENOLDA. E. (Eds): Lipid Metabolism, Obesity and Diabetes Mellims: Impact upon Atherosclerosis. Georg Thieme Verlag, Stuttgart, 1974; p. 117. 13) COHEN A. M., TEtTELBAUM A., SALI~EI~IK R.: Genetics and Diet as Factors ha Development of Diabetes Mellims - MetaboLism 21, 235, 1972. 14) DAY R.: Problem of Diabetic Retinopathy - Sth. med. J. (Bgham, Ata.) 44, 549, 1951. 15) ENGEm',nANR. L., BI,ooI~WOI~rl4J. M. B. Jr.: Experimental Diabetic Retinopathy in Dogs - Arch. Ophthai. 73, 205, 1965. 16) ENGEI~MaNR. L., MEYER R. K., BU~SSELEa J. A.: Effect of Alloxan Diabetes and Steroid Hypertension on Retinal Vasculature - Amer. J. Ophtbal. 58, 965, 1964. 17) E~GLESONG.: Studies in Diabetes Mellitus - Acta Paediat. (Uppsala) 43 (Suppl. 97), t16, 1954. 18) FEDERMANJ. L., GERRITSENG. C.: The Retinal Vasculature of the Chinese Hamster: a Preliminary Study - Diabetologia 6, 186, 1970. 19) FoGI,Ia V. G., MANClNI R. E., Ct~r,.DEZaA. F.: Glomerular Lesions in the Diabetic Rat - A,M,A. Arch. Path. 50, 75, 1950. 20) GELLMaN D. D., PIRANI C. L., SOOTHIL~ J. F., MI:E~eC~E R. C., KAr,x R. M.: Diabetic Nephropathy: a Clinical and Pathologic Study Based on Renal Biopsies Medicine (Baltimore) 38, 321, 1959, 21) GIBBS G, E., WILSON R. B., GII~Fom~H. Jr.: Glomeru]osclerosis in the Long-Term Alloxan Diabetic Monkey - Diabetes 15, 258, 1966. 22) GONET A. E., S:rAUrFaCHZRW., PICTET R., R~NOLI) A. E.: Obesiv] and Diabetes Mellitus with Stricldng Congenital Hyperptasia of the Islets of Langerhans in Spiny Mice (Acomys cahirinus). I. Histological Findings and Preliminary Metabolic Observations - DiabetoloNa t, 162, 1965. 23) Iq_~CKeLD. B., SCHMIDT-NIELSENK., HainES H. B., MIKAT E.: Diabetes Mellitus in the Sand rat (Psammomys obesus). Pa~hologic Studies - Lab. Invest. I4, 200, 1965. 24) HAUSLERH. R., SI~AYT. M,, CAMPBEI,L J.: Retinopathy in a Dog Following Diabetes Induced by Growth Hormone - Diabetes 13, 122, 1964. 25) H_ELLMa~ZB.: Studies in Obese-Hyperglycemic Mice - Arm. N, Y. Acad. Sci. I3t, 541, 1965. 26) HotqeY G. E., P~rsE-DaWES J., Ro~exTs D. M.: A Survey o{ Nephropathy in Young Diabetics - Quart. J. Med. 31,473, 1962. 27) K.t~:scm,r~t R., LEO~'0LD I. H.: Retinal Changes in the Alloxan Diabetic Rat Maintained on a High Fat Diet - Arch. Ophthal. 64, 681, 1960. 28) KoeN~lJv T.: Studies in Diabetic Rednopathy. An Investigation of 1,000 Cases of Diabetes - Acta reed. scand. 153, 81, 1955. 29) K~l~t.~'~ H., M~I4NEI~ H., L.~NC,Ee E.: Retinopathie und GIomerutosklerose bei Diabetikern - Med. Klin. 64, 747, 1969. 30) LaWE J. E.: Renal Changes in Hamsters with Hereditary Diabetes Mellitus - Arch. Path. 73, 86, 1962. 31) L~V~E R., LAZZAI~I~I-Ro~ER~SO~A. J., FOGLt~ V. G., SI~6E~ J.: The Retina in Experimental Diabetic Rats - Arch. Ophtha!. 70, 253, 1963. 32) M.~'~" G. U., G o ~ a ~ J. W., A~aMs L.: The Renal Lesions Associated with Experimental Diabetes in the Rat - Amer. J. Pathot. 27, 857, 1951. 33) Ol~s~covH., S~EEN OLSEN T., NIELSEN K., RAFAELSENO. J., LUNDB,~KK.: Kidney Lesions in the Rats wire Severe Long-Term Alloxan Diabetes. I. Influence of Age, Altoxan Damage and Insulin Administration - Diabetologia I, 172, 1965. 34) PATZA., B~m~ow J. W., MAUMENEZA. E., Cox J.: Studies on Diabetic Retinopathy and Nephropathy in Spontataeous Canine Diabetes - Diabetes 14, 700, t965. 35) POMETT,~D., TA:roN J., P,~ES S. B., KUWA~ARAT.: Retinal Vascular Change in the Chinese Hamster - Diabetologia 2, 215, 1966. 36) SrBAY T. M., HAUSLE:~H. R.: Eye Findings {n Two Spontaaeously Diabetic Related Dogs - Amer. J, Ophthal. 63, 289, 1967.
Re~iaests /or t'eprints shoalld be Mdressed to: LUTZA YANKO
Department o/ Ophthalmology Hadassah University Hospital ]erusMem o lsrae! 65
