E x p e r i m e n t a l Production of Varicocele and its Effect o n T e s t e s DANDIA, S.D.,* BAGREE, M.M.,* VYas, C.P.,* SINGH, H.,* PEZ~DSE, A.K.* and JosHI, K . R . * * A B S T R A C T : Parital obstruction of left renal vein leads to producution of varicocele in a fairly short period, i.e. ; even within a month. Collateral venous channels play an important role in the formation a n d degree of varicocele. Varicocele has got a depressive effect on the spermatogenesis on the side of varicocele as well as on opposite testes. Leydig cells and interstitial tissue flourish at the expense of gonadal elements. T h e factors affecting the spermatogenesis are different from those of other tissues of the testes. KEY WORDS: spermatogenesis.
varicocele, partial obstruction; testes, testicular biopsy;
V a r i c o c e l e has lately assumed a significant position amongst the causes of male sterility but its etiology is still uncertain. I n the present study an attempt has been m a d e to confirm the clinical data, whether partial obstruction of the left renal vein does lead to varicocele and if so, w h a t are the progressive changes in the testes of the varicocele side as well as on the testis of the normal side. MATERIALS AND METHODS T w e n t y five healthy adult mongrel dogs weighing between 15-18 kilograms of either sex were subjected to partial ligation of left renal vein at a point beyond the junction of spermatic vein to it but prior to its drainage into the inferior vena cava. U n d e r intravenous sodium pentothal anesthesia (25 mg/kg body wt.), the a b d o m a n was opened by a midline incision m a d e from the xiphisternum to about five centimenters above pubic symphysis. Anterior rectus sheath was cut, muscle was retracted laterally a n d peritoneum was incised. T h e intestines were packed a w a y and the spleen was retracted upwards. Left renal vein was exposed up to its termination into the inferior vena cava. For the partial obliteration o f the vein, it was ligated with 00 silk thread tied over the tip of an artery forceps (Crile's m e d i u m sized curved artery forceps 51/2" long with nickel plate) which was kept along the renal vein at the site ofligation and which was removed after the thread had been tied, so that only a partial occlusion resulted (Fig. 1). Thus using the same artery forceps in all the dogs and tying the thread at fixed point on it (five millimeters from the tip) almost an equal degree of constriction was achieved. T h e factor of individual variation of the original size of vein in different animals was minimized by selecting the animals of almost equal b o d y weights (15 to 18 kg). T h e a b d o m e n was sutured in layers.
*Department of Surgery and **Department of Pathology; Sardar Pate Medical College, Bikaner-334001 (India) JAPANESEJOURNALOF SURGERY,VOL. 9, No. 4, pp 372-378, 1979
Volume 9 Number 4
373
Experimental Production of Varicocele
T h e s p e r m a t i c cords were observed every m o n t h , for three m o n t h s b y e x p l o r i n g the i n g u i n a l regions a n d at the time of t h i r d e x p l o r a t i o n the incision was e x t e n d e d u p t o the r e n a l vein on b o t h the sides a n d finally the cords along w i t h the testes were r e m o v e d from b o t h sides. A t the e n d of second m o n t h d u r i n g e x p l o r a t i o n of i n g u i n a l regions testicular biopsies from b o t h testes were taken (first testicular biopsy) a n d finally at the end o f t h i r d m o n t h a g a i n b o t h t e s t e s - w e r e subjected to biopsies (second testicular biposy). R o u t i n e h e m a t o x y l e n e a n d eosin stained paraffin sections were p r e p a r e d to study the s t r u c t u r a l changes in testes. F o r control, five similar dogs were subjected to r e n a l vein e x p l o r a t i o n on the left side as in cases of a n i m a l s u n d e r test b u t w i t h o u t tying a t h r e a d r o u n d the r e n a l vein. R e p e a t e d explorations of s p e r m a t i c cords a n d testicular biopsies were taken in the same m a n n e r as t h a t of e x p e r i m e n t a l animals. RESULTS D i l a t a t i o n a n d tortuosity of p a m p i n i f o r m plexuses were n o t i c e d only on the test side. This resulted in an overall increase in d i a m e t e r of s p e r m a t i c cords. D e p e n d i n g u p o n ratio of thickness of s p e r m a t i c c o r d o f test side a n d control side a n a r b i t r a r y g r a d a t i o n of varicoceles was done. Thus, m a r k e d varicoceles m e a n t t h a t calibre of left s p e r m a t i c cord was a p p r o x i m a t e l y two times t h a t of right side, m o d e r a t e m e a n t t h a t increase in the size of c o r d was 1.5 times a n d m i l d varicoceles were h a v i n g the i n c r e m e n t in the c o r d size of a b o u t 1.25 times t h a t of right side or less t h a n that. T h e w i d t h of the s p e r m a t i c c o r d was m e a s u r e d at a fixed p o i n t of t h r e e centimeters a b o v e the u p p e r pole of t h e testis. Varicocele d i d not develop in a n y of the control g r o u p of animals ( T a b l e 1). T w e n t y - t h r e e o u t of 25 a n i m a l s e x h i b i t e d : v a r i c o c e l e at the first observation. V a r i cocele was absent in two a n d very m i l d in two animals. Thickness of the varicocele was observed to d i m i n i s h in m o r e t h a n 50 p e r c e n t of the a n i m a l s at subsequent observations. Thus, out of eight a n i m a l s h a v i n g m a r k e d varicocele only four r e t a i n e d the same degree after two m o n t h s a n d only three after three months. S i m i l a r l y out of 13 a n i m a l s w i t h m o d e r a t e varicocele 11 a n d 6 m a i n t a i n e d the same degree of varicocele after second a n d
T a b l e 1.
Experimental production of varicocele
Degree of varicocele
Number of dogs First Second Third month month month
Test group (25) Marked Moderate
8
4
--
4
-
Mild
1
-
4
13
11
6
--
--
--
No varicocele Control group (5) No varicocele
3
5
2
2
2 2
2 2
2 2
5
5
5
374
Dandia et al.
Jpn. J. Surg. Dec. 1979
Fig. 1.
Fig. 2. third month respectively (Table 1). Extensive collateral venous channels were observed, particularly involving the ureteric veins, in animals showing regression of varicocele as well as in animals who failed to develop varicocele at the first instance. None of the control animals showed these anastomosing channels. The histopathological changes in both testes were as shown in Table 2. In two dogs in which varicocele did not develop and in control animals, testicular biopsies did not
Volume 9 Number 4
375
Experimental Production of Varicocele
T a b l e 2.
Various changes in testicular biopsies of dogs, subjected to partial ligation of the left renal vein after second and third months (only test group) First biopsy
Pathology 1. Congestion 2. Arrest of spermatogenesis 3. Increase in interstitial tissue 4. Leydig cell hyperplasia
T a b l e 3.
Varicocele
Second biopsy
Left
right
Left
right
19(76%)
--
10(40%)
--
23(92%)
21(84%)
23(92%)
23(92%)
19(76%)
11 ( 4 4 % )
23(92%)
20(80%)
1(4%)
1(4%)
17(68%)
6(24%)
Degree of arrest of spermatogenesis in relation to the degree of varicocele, numbers representing the animals so affected Complete arrest
Primary spermatocyte
Secondary spermatocyte
right
left
left
right
3 3
1 3
.
-.
.
-9
-4
5 2
2 7
left
right
Spermatids only left
right
--
--
1
6
Marked I biopsy II biopsy Moderate I biopsy II biopsy Mild I biopsy II biopsy
-2
1
1 6
-4
2 1
-4
1 --
2 --
Total
17
9
15
14
12
15
2
8
T a b l e 4.
1
1 .
.
2
9 .
. 7
.
.
.
Degree of Leydig cell hyperplasia in various animals
Degree of hyperplasia
First biopsy
Second biopsy
left
right
left
Mild Moderate
1(4%) --
1(4%) --
14(56%) 3(12%)
6(24%) --
right
Total
1(4%)
1(4%)
17(68%)
6(24%)
show a n y change. T h e degree of arrest of the spermatogenesis was generally parallel to the severity of varicocele (Table 3). T h e left testis was affected earlier a n d right ones followed (Table 2). Arrest of spermatogenesis was seen i n 21 out of the 23 dogs which developed varicocele, on the right side a n d i n all the 23 dogs on the left side at the e n d of second m o n t h , whereas all the 23 a n i m a l s h a d a n arrest ofspermatogenesis o n b o t h sides at the e n d of third m o n t h . Leydig cell hyperplasia, interstitial edema, fibrosis a n d infiltration with chronic
376
Dandia et al.
Jpn. J. Surg. Dec. 1979
Fig. 3. inflammatory cells also occurred first on the left side and later on the right side. Congestion was, however, observed only in the left testis and that too in only nineteen animals at first biopsy and in ten at second biopsy i.e. after second and third month after constriction of renal vein (Table 4). Discussion The present study demonstrates that partial occlusion of left renal vein results in varicocele formation in 92% of experimental animals. Cox et al.Z and Siderey & Killman 9 also observed dilatation and tortuousity of gonadal veins in the retroperitoneal area after partial or complete obstruction of left renal vein. Collateral venous channels have very important role in prevention of varicocele after partial occlusion of the renal vein. It was observed that rich plexus of collateral venous channels was present in animals which did not develop varicocele as well as in animals showing regression of varicocele. The present study has dealt with only one aspect of the etiopathogenesis of varicocele and it does not exclude the existence of other factors. But, in the light of this experimental evidence the possibility of some occlusive lesion of left testicular vein or renal vein beyond the opening of left resticular vein into it should always be considered in all cause of left sided varicocele. The structural changes in the testes of the dogs of the present study are by and large
Volume 9 Number 4
Experimental Production of Varicocele
377"
Fig. 4.
in agreement with the previous reports by other workers.l,4,6, 7 It is of interest to note that the histological involvement of contralateral testes rapidly approximated to that of ipsilateral one after partial occlusion of a testicular or renal vein. Bilateral arrest of spermatogenesis has also been reported earlier in cases of unilateral varicoceles.5, 6 The earliest and most profound affected component due to varicocele was the spermatogonial tissue which showed a remarkable degree of involvement on both testes. O n the other hand, the unequal histological changes between both testes due to unilateral varicocele included congestion, increase in interstitial tissue and Leydig cell hyperplasia. This indicates that (1) factor which determines normal spermatogenesis is more delicately poised as compared to other factors having influence over the other histological features of the testes and (2) factors which determine reaction on the interstitial tissue and Leydig cells are different from those which are capable of influencing the process of spermatogenesis. So far the temperature of testicular tissue has been predominantly incriminated in this regard.3, 7 With the increase in the volume of the blood followed by relative stagnancy in the peripheral area of the occlusive vessel, consequent diminution in the concentration of oxygen and exsudation of the protein-rich fluid in the interstitial tissue may occur and is conceivable that more differentiated and sophisticated elements such as spermatogenesis would succumb and the relatively hard structures which comprise the connective tissue may flourish. Since these probabilities gather potential gradually, the consequent increase in the interstitial tissue is relatively late, but a progressive feature. Leydig cell hyperplasia may have a comparable genesis to that of increased interstitial
378
Dandia et al.
Jpn. J. Surg. Dec. 1979
tissue b y h e m o d y n a m i c u p s e t t i n g , t h e a t r o p h y o f s p e r m a t o g e n i c tissue w o u l d c a u s e a n i n c r e a s i n g a v a i l a b l e v a s c u l a r s u p p l y to o t h e r e l e m e n t w h i c h c o m p r i s e t h e L e y d i g cells. T h e h y p e r p l a s i a o f L e y d i g cells o b s e r v e d in a n i m a l s o f t h e p r e s e n t s t u d y ( T a b l e 4) w e r e also o b s e r v e d p r e v i o u s l y 6 in 5 % of t h e testicular biopsies in p a t i e n t s o f v a r i c o c e l e . (Received for publication on N o v e m b e r 1, 1974) References 1. Charney, C.W. : Effects of varicocele on fertility. Results of varicocelectomy, Fertility and Sterility 13: 47, 1962. 2. Cox, J.S.T., John, H.T., Benkole, M.A. and Warren, R. : Collateral circulation after renal vein occlusion, Surgery 52: 875-882, 1962. 3. Dahl and Itarrick: Vascular mechanism for maintaining testieular temperature, Surg. @nee. Obstet. 108: 6, 1967. 4. Davis., J.E. : Varicocele as a contributing factor to male infertility, Int..]our. Fertility 10: 359-372, 1965. 5. Dubln L. and Hotchkiss, R.S.: Testis biopsy in
6.
7. 8. 9.
subfertile mert with varicocele, Fertility and Sterility 20: 50-57, 1969. Etriby, A., Grigis, S., Hefnawy, H. and Ibrahim, A.A. : Testicular changes in subfertile males with varieocele, Fertility and Sterility 18" 666-671, 1967. Hanley, tt.G. : Surgical correction of errors of temperature regulation Proc. Congr. Fert. Ster. 1956. Scott. L.S. and Young, D.: Varicocele and study of its effects on human spermatogenesis, Fertility and Sterility 13: 325-334, 1962. Sidrey, t-I. and Killmen, J,W. : The effect of acute occlusion of the renal vein in dogs, Surgery 59: 282-285, 1966.
varicocele, partial obstruction; testes, testicular biopsy;
V a r i c o c e l e has lately assumed a significant position amongst the causes of male sterility but its etiology is still uncertain. I n the present study an attempt has been m a d e to confirm the clinical data, whether partial obstruction of the left renal vein does lead to varicocele and if so, w h a t are the progressive changes in the testes of the varicocele side as well as on the testis of the normal side. MATERIALS AND METHODS T w e n t y five healthy adult mongrel dogs weighing between 15-18 kilograms of either sex were subjected to partial ligation of left renal vein at a point beyond the junction of spermatic vein to it but prior to its drainage into the inferior vena cava. U n d e r intravenous sodium pentothal anesthesia (25 mg/kg body wt.), the a b d o m a n was opened by a midline incision m a d e from the xiphisternum to about five centimenters above pubic symphysis. Anterior rectus sheath was cut, muscle was retracted laterally a n d peritoneum was incised. T h e intestines were packed a w a y and the spleen was retracted upwards. Left renal vein was exposed up to its termination into the inferior vena cava. For the partial obliteration o f the vein, it was ligated with 00 silk thread tied over the tip of an artery forceps (Crile's m e d i u m sized curved artery forceps 51/2" long with nickel plate) which was kept along the renal vein at the site ofligation and which was removed after the thread had been tied, so that only a partial occlusion resulted (Fig. 1). Thus using the same artery forceps in all the dogs and tying the thread at fixed point on it (five millimeters from the tip) almost an equal degree of constriction was achieved. T h e factor of individual variation of the original size of vein in different animals was minimized by selecting the animals of almost equal b o d y weights (15 to 18 kg). T h e a b d o m e n was sutured in layers.
*Department of Surgery and **Department of Pathology; Sardar Pate Medical College, Bikaner-334001 (India) JAPANESEJOURNALOF SURGERY,VOL. 9, No. 4, pp 372-378, 1979
Volume 9 Number 4
373
Experimental Production of Varicocele
T h e s p e r m a t i c cords were observed every m o n t h , for three m o n t h s b y e x p l o r i n g the i n g u i n a l regions a n d at the time of t h i r d e x p l o r a t i o n the incision was e x t e n d e d u p t o the r e n a l vein on b o t h the sides a n d finally the cords along w i t h the testes were r e m o v e d from b o t h sides. A t the e n d of second m o n t h d u r i n g e x p l o r a t i o n of i n g u i n a l regions testicular biopsies from b o t h testes were taken (first testicular biopsy) a n d finally at the end o f t h i r d m o n t h a g a i n b o t h t e s t e s - w e r e subjected to biopsies (second testicular biposy). R o u t i n e h e m a t o x y l e n e a n d eosin stained paraffin sections were p r e p a r e d to study the s t r u c t u r a l changes in testes. F o r control, five similar dogs were subjected to r e n a l vein e x p l o r a t i o n on the left side as in cases of a n i m a l s u n d e r test b u t w i t h o u t tying a t h r e a d r o u n d the r e n a l vein. R e p e a t e d explorations of s p e r m a t i c cords a n d testicular biopsies were taken in the same m a n n e r as t h a t of e x p e r i m e n t a l animals. RESULTS D i l a t a t i o n a n d tortuosity of p a m p i n i f o r m plexuses were n o t i c e d only on the test side. This resulted in an overall increase in d i a m e t e r of s p e r m a t i c cords. D e p e n d i n g u p o n ratio of thickness of s p e r m a t i c c o r d o f test side a n d control side a n a r b i t r a r y g r a d a t i o n of varicoceles was done. Thus, m a r k e d varicoceles m e a n t t h a t calibre of left s p e r m a t i c cord was a p p r o x i m a t e l y two times t h a t of right side, m o d e r a t e m e a n t t h a t increase in the size of c o r d was 1.5 times a n d m i l d varicoceles were h a v i n g the i n c r e m e n t in the c o r d size of a b o u t 1.25 times t h a t of right side or less t h a n that. T h e w i d t h of the s p e r m a t i c c o r d was m e a s u r e d at a fixed p o i n t of t h r e e centimeters a b o v e the u p p e r pole of t h e testis. Varicocele d i d not develop in a n y of the control g r o u p of animals ( T a b l e 1). T w e n t y - t h r e e o u t of 25 a n i m a l s e x h i b i t e d : v a r i c o c e l e at the first observation. V a r i cocele was absent in two a n d very m i l d in two animals. Thickness of the varicocele was observed to d i m i n i s h in m o r e t h a n 50 p e r c e n t of the a n i m a l s at subsequent observations. Thus, out of eight a n i m a l s h a v i n g m a r k e d varicocele only four r e t a i n e d the same degree after two m o n t h s a n d only three after three months. S i m i l a r l y out of 13 a n i m a l s w i t h m o d e r a t e varicocele 11 a n d 6 m a i n t a i n e d the same degree of varicocele after second a n d
T a b l e 1.
Experimental production of varicocele
Degree of varicocele
Number of dogs First Second Third month month month
Test group (25) Marked Moderate
8
4
--
4
-
Mild
1
-
4
13
11
6
--
--
--
No varicocele Control group (5) No varicocele
3
5
2
2
2 2
2 2
2 2
5
5
5
374
Dandia et al.
Jpn. J. Surg. Dec. 1979
Fig. 1.
Fig. 2. third month respectively (Table 1). Extensive collateral venous channels were observed, particularly involving the ureteric veins, in animals showing regression of varicocele as well as in animals who failed to develop varicocele at the first instance. None of the control animals showed these anastomosing channels. The histopathological changes in both testes were as shown in Table 2. In two dogs in which varicocele did not develop and in control animals, testicular biopsies did not
Volume 9 Number 4
375
Experimental Production of Varicocele
T a b l e 2.
Various changes in testicular biopsies of dogs, subjected to partial ligation of the left renal vein after second and third months (only test group) First biopsy
Pathology 1. Congestion 2. Arrest of spermatogenesis 3. Increase in interstitial tissue 4. Leydig cell hyperplasia
T a b l e 3.
Varicocele
Second biopsy
Left
right
Left
right
19(76%)
--
10(40%)
--
23(92%)
21(84%)
23(92%)
23(92%)
19(76%)
11 ( 4 4 % )
23(92%)
20(80%)
1(4%)
1(4%)
17(68%)
6(24%)
Degree of arrest of spermatogenesis in relation to the degree of varicocele, numbers representing the animals so affected Complete arrest
Primary spermatocyte
Secondary spermatocyte
right
left
left
right
3 3
1 3
.
-.
.
-9
-4
5 2
2 7
left
right
Spermatids only left
right
--
--
1
6
Marked I biopsy II biopsy Moderate I biopsy II biopsy Mild I biopsy II biopsy
-2
1
1 6
-4
2 1
-4
1 --
2 --
Total
17
9
15
14
12
15
2
8
T a b l e 4.
1
1 .
.
2
9 .
. 7
.
.
.
Degree of Leydig cell hyperplasia in various animals
Degree of hyperplasia
First biopsy
Second biopsy
left
right
left
Mild Moderate
1(4%) --
1(4%) --
14(56%) 3(12%)
6(24%) --
right
Total
1(4%)
1(4%)
17(68%)
6(24%)
show a n y change. T h e degree of arrest of the spermatogenesis was generally parallel to the severity of varicocele (Table 3). T h e left testis was affected earlier a n d right ones followed (Table 2). Arrest of spermatogenesis was seen i n 21 out of the 23 dogs which developed varicocele, on the right side a n d i n all the 23 dogs on the left side at the e n d of second m o n t h , whereas all the 23 a n i m a l s h a d a n arrest ofspermatogenesis o n b o t h sides at the e n d of third m o n t h . Leydig cell hyperplasia, interstitial edema, fibrosis a n d infiltration with chronic
376
Dandia et al.
Jpn. J. Surg. Dec. 1979
Fig. 3. inflammatory cells also occurred first on the left side and later on the right side. Congestion was, however, observed only in the left testis and that too in only nineteen animals at first biopsy and in ten at second biopsy i.e. after second and third month after constriction of renal vein (Table 4). Discussion The present study demonstrates that partial occlusion of left renal vein results in varicocele formation in 92% of experimental animals. Cox et al.Z and Siderey & Killman 9 also observed dilatation and tortuousity of gonadal veins in the retroperitoneal area after partial or complete obstruction of left renal vein. Collateral venous channels have very important role in prevention of varicocele after partial occlusion of the renal vein. It was observed that rich plexus of collateral venous channels was present in animals which did not develop varicocele as well as in animals showing regression of varicocele. The present study has dealt with only one aspect of the etiopathogenesis of varicocele and it does not exclude the existence of other factors. But, in the light of this experimental evidence the possibility of some occlusive lesion of left testicular vein or renal vein beyond the opening of left resticular vein into it should always be considered in all cause of left sided varicocele. The structural changes in the testes of the dogs of the present study are by and large
Volume 9 Number 4
Experimental Production of Varicocele
377"
Fig. 4.
in agreement with the previous reports by other workers.l,4,6, 7 It is of interest to note that the histological involvement of contralateral testes rapidly approximated to that of ipsilateral one after partial occlusion of a testicular or renal vein. Bilateral arrest of spermatogenesis has also been reported earlier in cases of unilateral varicoceles.5, 6 The earliest and most profound affected component due to varicocele was the spermatogonial tissue which showed a remarkable degree of involvement on both testes. O n the other hand, the unequal histological changes between both testes due to unilateral varicocele included congestion, increase in interstitial tissue and Leydig cell hyperplasia. This indicates that (1) factor which determines normal spermatogenesis is more delicately poised as compared to other factors having influence over the other histological features of the testes and (2) factors which determine reaction on the interstitial tissue and Leydig cells are different from those which are capable of influencing the process of spermatogenesis. So far the temperature of testicular tissue has been predominantly incriminated in this regard.3, 7 With the increase in the volume of the blood followed by relative stagnancy in the peripheral area of the occlusive vessel, consequent diminution in the concentration of oxygen and exsudation of the protein-rich fluid in the interstitial tissue may occur and is conceivable that more differentiated and sophisticated elements such as spermatogenesis would succumb and the relatively hard structures which comprise the connective tissue may flourish. Since these probabilities gather potential gradually, the consequent increase in the interstitial tissue is relatively late, but a progressive feature. Leydig cell hyperplasia may have a comparable genesis to that of increased interstitial
378
Dandia et al.
Jpn. J. Surg. Dec. 1979
tissue b y h e m o d y n a m i c u p s e t t i n g , t h e a t r o p h y o f s p e r m a t o g e n i c tissue w o u l d c a u s e a n i n c r e a s i n g a v a i l a b l e v a s c u l a r s u p p l y to o t h e r e l e m e n t w h i c h c o m p r i s e t h e L e y d i g cells. T h e h y p e r p l a s i a o f L e y d i g cells o b s e r v e d in a n i m a l s o f t h e p r e s e n t s t u d y ( T a b l e 4) w e r e also o b s e r v e d p r e v i o u s l y 6 in 5 % of t h e testicular biopsies in p a t i e n t s o f v a r i c o c e l e . (Received for publication on N o v e m b e r 1, 1974) References 1. Charney, C.W. : Effects of varicocele on fertility. Results of varicocelectomy, Fertility and Sterility 13: 47, 1962. 2. Cox, J.S.T., John, H.T., Benkole, M.A. and Warren, R. : Collateral circulation after renal vein occlusion, Surgery 52: 875-882, 1962. 3. Dahl and Itarrick: Vascular mechanism for maintaining testieular temperature, Surg. @nee. Obstet. 108: 6, 1967. 4. Davis., J.E. : Varicocele as a contributing factor to male infertility, Int..]our. Fertility 10: 359-372, 1965. 5. Dubln L. and Hotchkiss, R.S.: Testis biopsy in
6.
7. 8. 9.
subfertile mert with varicocele, Fertility and Sterility 20: 50-57, 1969. Etriby, A., Grigis, S., Hefnawy, H. and Ibrahim, A.A. : Testicular changes in subfertile males with varieocele, Fertility and Sterility 18" 666-671, 1967. Hanley, tt.G. : Surgical correction of errors of temperature regulation Proc. Congr. Fert. Ster. 1956. Scott. L.S. and Young, D.: Varicocele and study of its effects on human spermatogenesis, Fertility and Sterility 13: 325-334, 1962. Sidrey, t-I. and Killmen, J,W. : The effect of acute occlusion of the renal vein in dogs, Surgery 59: 282-285, 1966.
