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International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:16 No:05 1
160805-3737- IJBAS-IJENS @ October 2016 IJENS I J E N S
Morphological Observations on the Development of
The Mesonephros
of The Dromedary Camel Foetus Sabah. O. Elgozouli and D.I.Osman
Department of Anatomy, Faculty of Veterinary Medicine, University of Khartoum- Khartoum North -13314, Sudan.
sabahomer2@yahoo.com.
Abstract-- This investigation was carried out to reveal and
evaluate the pattern of the mesonephros growth in the
dromedary camel. 30 embryos and foetuses (2 cm CVRL to 24
cm CVRL) were used to study the histology of the mesonephros.
The mesonephros of the dromedary camel foetus, consisted of
small glomeruli (primary) and two types of tubules with a set of
capillaries in between. The large glomeruli (giant glomeruli) were
observed immediately before the time of gonads differentiation to
male or female between 2 and 3 cm CVRL (71 and 74 days of
age) towards the positions where the gonads were developed.
Thus in male fetuses, the giant glomeruli surrounded the hilus at
the cranial part of the mesonephros and in this place the testes
were developed, whereas in the female foetuses the giant
glomeruli surrounded the hilus at the medial border of the
mesonephros and this the position where the developing ovaries
were observed. The large glomeruli were limited in number when
they first appeared (not more than 20) then regressed soon after
the gonads underwent differentiation, while the small
mesonephric glomeruli were observed in different stages of
development till 17 cm CVRL (112 days of age). It was clear from
these observations, that the differentiation of the gonad of the
dromedary camel foetuses could be related to the position of the
gonads in relation to the mesonephros and according to the
position where the giant glomeruli were arranged.
Index Term-- giant glomeruli mesonephros Trimester
INTRODUCTION
Regulation of mesonephric differentiation has been
studied in some mammals, such as mice (Upadhyay, Luciani
and Zamboni, 1979), sheep (Upadhyay and Zamboni, 1982),
rat and mouse (Smith and Mackay, 1991; Merchant-larios,
Moreno-mendoza and Buehr, 1993; Sainio, Hellstedt,
Kreidberg, Saxén and Sariola, 1997) and in goat (Magras,
Alifakiotis and Pampoukidou, 1997). In human (Martino and
Zamboni, 1966) and pig (Tiedemann and Egerer, 1984), the
mesonephros is well developed as excretory organ during
embryonic development. In murine species, however, the
mesonephros is primitive and non-excretory (Zamboni and
Upadhyay, 1981; Smith and MacKay, 1991). The
histogenesis and morphology of the mesonephros of the foetus
of the dromedary camel have only been briefly studied by
Musa (1982), El-Harairy, Gabr and Attia (1998), Imam (2005)
and Aly (2007).
MATERIALAND METHODS
30 embryos and foetuses were collected from Tamboul
slaughter point and from Elsalam slaughter house. The curved
crown rump length (CVRL) equation Y = 0.366X - 23.99
which was described by Elwishy, Hemeida, Omer, Mobarak
and Elsyed (1981) was used to determine the age of the
fetuses. The whole embryos and the mesonephros of the
foetuses were fixed in 10% buffered formalin. General and
special histological stains were used to investigate the
different components of the mesonephros. Small pieces of
1x1x1 mm of tissue from mesonephros were fixed in 2.5%
glutaraldehyde in 1M cacodylate buffer (Ph. 7.3), post fixed in
cold 1M phosphate buffer 2% osmium tetroxide (PH. 7.3),
then semi-thin sections 0.5 micron stained by Toluidine blue.
RESULTS
Before the time of gonads differentiation the
mesonephros presented three surfaces (dorsal, ventral and the
lateral surfaces), three borders (medial, dorso-lateral and
ventro-lateral borders) and two poles (cranial and caudal). It
resembled in outline a lemon fruit. The lateral surface was
smooth and strongly convex. The ventral and the dorsal
surfaces were slightly flattened and were joined at an angle at
the hillus ventrally. These surfaces were related to the gonads
at the hillus, to the metanephros at the dorsal surface and to
the adrenal gland cranially. The mesonephric and the
paramesonephric ducts run along the ventro-lateral border
(Fig.1).
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Fig. 1. Photograph of whole dromedary camel foetus of 5 cm CVRL (79 days of age) after the removal of the viscera, showing the mesonephros (m), ovaries (long arrow),
mesonephric duct and paramesonephric duct (arrow heads).
In 2cm CVRL (71 days of age) camel foetus, the mesonphros was well developed, consisted of mesonephric corpuscles,
mesonephric tubules and mesonephric duct. The mesonephric tubules were long, numerous and coiled, had different diameter and
shapes and arranged in many rows dorsoventrally. These tubules could be differentiated into two types:
(a) Mesonephric tubules lined with single layer of low cuboidal cells with spherical central nuclei and clear lumen (b)
Mesonephric tubules lined by high cuboidal cells with big spherical nuclei and their luminal border was studded
with clearly visible microvilli, and contained material in its lumen. These tubules occupied almost the entire
mesonephros and a network of capillaries was found between these tubules (Fig.2).
Fig. 2. Photomicrograph of foetus during first trimester demonstrating mesonphric tubules lined by high cuboidal cells with pale nuclei and
many vacuoles of different sizes were scattered in the cytoplasm of the two types of mesonephric tubules but more in the tubule lined by high cuboidal cells. Note the presence of blood vessels filled with blood between the tubules. Toludine blue stain. X40.
The small glomeruli occupied the medial portion
between the mesonephric tubules and they were in the form of
masses of cells just like small nodules at the ends of the
tubules and surrounded by flat cells and had a narrow urinary
space. In 3cm CVRL (74 days of age) foetus, large glomeruli
(giant glomeruli) were observed at the ventromedial part of the
m
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mesonephros . The mesonephric duct (Wolffian duct) was a
large duct and lined with cuboidal cell and situated at the
ventrolateral part of the mesonephros. The paramesonephric
duct (Müllerian duct) was small and lined with tall columnar
cells and running together with the mesonephric duct. In 4cm
CVRL (76 days of age) foetus, there was a fissure appeared
ventrally between the giant glomerular zone and the
metanephric tissue compressing the mesonephros toward the
fissure line. At this stage, the mesonephros was partially
divided into two parts, cranial and caudal. In male foetuses, a
group of mesonephric tubules in the cranial part were small in
diameter and their lining cells were changed to columnar. The
interstitial tissue between these tubules was connective tissue
rich in mesenchymal cell, fibroblasts and smooth muscle
fibres, and this cranial part of the mesonephros was the zone
where the testes would develop and suspended. The ovaries
appeared and developed at the medial part of the mesonephros
(Fig.3).
Fig. 3. Photomicrograph of some mesonephric tubules (T) in male dromedary foetus of 4cm (74 days of age) situated at the cranial pole of the mesonephros and ventral surface of the mesonephros close to the testes which grew dorsal to this zone. G: Giant glomeruli.
H&E stain. X10.
In 4.8 cm CVRL (79 days of age) female foetus, the pressure
of both the developed metanephros dorsally and the ovary
ventrally, divided the left mesonephros into small cranial and
large caudal portions. The caudal portion was more active than
the cranial one which showed signs of regression in foemale
fetuses. The right mesonephros was elongated and remained as
one unit. The small mesonephric glomeruli were demonstrated
in different stages of development and with different shapes
(“S” shape and “ɘ” comma shape). Glomeruli with and
without blood entrance were surrounded by glomerular
capsule which was lined by simple squamous cells at the
parietal layer and podocytes and capillary plexus at its visceral
layer with narrow urinary space
T
G
International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:16 No:05 4
160805-3737- IJBAS-IJENS @ October 2016 IJENS I J E N S
Fig.4: Photomicrograph of small mesonephric glomeruli at different stages of development in “S” shape, “ɘ” comma shape, glomeruli with blood vessels entrance (V) and without blood vessels entrance, from foetus during first trimester.
Toludine blue stain X 40.
The large glomeruli (Giant glomeruli) were grouped at
the medial portion of the mesonephros and surrounded the
hilus close to the ovaries in female foetues, while the Giant
glomeruli in male foetus, were concentrated in the cranial part
of the mesonephros close to the testes. The large glomeruli
were lined with two types of cells: squamous cells and high
squamous or dome shape cells in the parietal layer of
glomerular capsule with wide urinary space. The blood
vessels of the giant glomeruli were in the form of tuft of
sinuses (Fig.5).
Fig. 5. Photomicrograph of mesonephroic large (Giant) glomeruli from foetus of 17cm CVRL(112 days of age) lined with squamous cells (s) and
high squamous (dome shape) cells (d) in the parietal layer of glomerular capsule, had a wide urinary space and the blood vessel in the form of tuft
of sinuses. P: Podocytes cells. Toludine blue stain. X100 .
Haemopoitic cells in different stages of development
and numerous primordial germ cells were observed in the
parenchyma of the giant glomeruli and in the small glomruli.
Large podocytes lined the visceral capsular layer of Bowman
of the mesonephric giant glomeruli.
In 6 cm CVRL (82 days of age) male foetus , the
testis was observed as small mass suspended by the
mesogonadal ligament to the cranial pole of the mesonphros
and connected to the zone of the developed efferent ductules.
Almost all the giant glomeruli in male foetuses were
accumulated at the cranial part of the mesonephros toward the
testes. Some mesonphric tubules and some giant glomeruli
situated beneath the testes adhered with the testes and became
regular tubules lined with cuboidal cells (Fig.6).
v
s
ɘ
d
s
P
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Fig. 6.A. Photomicrograph of a male foetus of 6 cm CVRL (82days of age), demonstrating the testes (T) suspended by the mesogonadal ligament to the cranial pole of the mesonphros (m) and connected to the zone of the developed efferent ductules. mt: metanephros . H&E stain. X4.
Fig. 6.B. Photograph of ventral view at the lumber region of dromedary camel male foetus of 14.5cm (105 days of age), demonstrating the testes (t) suspended to the mesonephros (m) at the cranial pole and attached to the metanephros (mt) obliquely.
In 7, 8 and 8.5 cm CVRL (85, 87and 89 days of age)
female foetuses, the caudal portion of the mesonephros was
well developed to become double the size of the metanephros
and it surrounded the metanephros ventrally in a spindle
shape. The cranial portion disappeared in the left
mesonephros of female foetuses, and retained as efferent
ductules in male foetuses. The Müllerian duct changed its
lining epithelium from tall columnar to pseudostraified cells in
female foetuses. Some signs of regression appeared during
these stages gradually in small parts of the mesonephros. The
first signs appeared in the capillaries in between the
mesonephric tubules which were invaded by large pale cells
with big dark nuclei. Then the lumen of the mesonephric
tubules was filled with material and sloughed and damaged
lining epithelial cells and plasma cell were observed scattered
between the lining epithelial cells. These signs of degeneration
were not observed in all tubules in the same time, but they
started in the cranial and lateral tubules of the left
mesonephros earlier than the right one in the female foetuses
and in the giant glomeruli more earlier than in the small
glomeruli. In 11 cm CVRL (96 days of age) foetus, the caudal
portion of the mesonephros regressed to half the size of the
metanephros. The left mesonphros was situated at the ventral
caudal portion of the metanephros, whereas the right one was
still in large size and elongated and it surrounded the caudal
half of the metanephros ventrolaterally. The mesonephric
A
B
t t
m
mt
mt
mt
m
T
A
International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:16 No:05 6
160805-3737- IJBAS-IJENS @ October 2016 IJENS I J E N S
capsule was in the form of dense connective tissue. New
generations of small glomeruli were observed in different
stages of development. The giant glomeruli were accumulated
at the hilus region in the left mesonephros and scattered along
the length of the right mesonephros in female foetuses and
connected to the ovary and the metanephros by a mesogonadal
ligament which was rich in blood supply (Fig. 7).
Fig. 7.a. Photomicrograph from a female foetus of 11 cm CVRL (96 days of age), illustrating giant glomeruli (g) situated at the hilus of the left
mesonephros connected to the ovary (o) and the metanephros by connective tissue rich in blood supply. The ovary at this stage was situated
above and cranial to and in contact to the left mesonephros. Müllerian duct (arrow). H&E stain. X4.
Fig. 7.b. Photograph of a ventral view of a female foetus of 11 cm (96 days of age), showing the ovary (o), mesonephros (m), metanephros (mt)
at different levels (the right metanephros was more cranial),the mesonephric duct (arrow) and the paramesonephric duct (arrow heads).
The ovaries at this stage were situated above and cranial to the
mesoneohros. The left ovary was large in size and in contact
with the left mesonephros, while the right ovary was small and
had no direct contact with the right mesonephros (Fig.7). The
Müllerian duct merged with the caudal pole of the developing
left ovary. Hematopoietic stem cells, blood cells,
macrophages, primordial germ cells, B and T lymphocytes
were seen within the giant glomeruli. Part of the right
mesonephros was in close contact with the right metanephros
and connective tissue with fine reticular fibres connected the
right metanephros with the right mesonephros. There was a
large space between the left metanephros and the left
mesoneohros. In 13 cm CVRL (101days of age) female
fetuses, the mesonphros parenchyma increased in cell
components mainly fibroblasts and smooth muscle fibres. The
giant glomeruli collapsed and the orifices of the mesonephric
ducts decreased in their calipers. At this stage, the cranial part
of the left mesonphros was connected to the ovary by
mesovarin, and this part of the mesoovarian enlarged cranially
and became as rosy funnel above the cranial pole of the left
mesonephros. Many small rounded tubules were lined with
simple cuboidal cells and some mesoneohric tubules were
filled with pink material at the cranial part of the
mesonephros. The mesonephros cell components in the matrix
increased especially at its lateral aspect which included the
paramesonephric duct. The paramesonephric ducts increased
in size in female foetuses. Long microvilli, pale nuclei, many
vacuoles of different sizes were found in the tubules which
were lined with low cuboidal and tubules lined with high
cuboidal epithelium but more in the tubules which were lined
by high cuboidal cells. In 15 cm CVRL (106 days of age), the
cranial part of the mesonephros was separated from the ovary
and became narrow and long, and its end was funnel shaped
and faced the ovary and lined with pseudostratified epithelium
(Fig.8)
a b
m m
mt mt
o o
o mesonephros
metanephro
s
g
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Photomicrograph from 15 cm CVRL (106 days of age) female foetuses, the cranial part of the left mesonphros was separated from the ovary and became narrow
and long, its end was funnel shaped, lined with pseudostratified epithelium and faced the ovary (arrow).
H&E stain. X4.
In 22 cm CVRL (126 days of age) foetus, the
mesonephros was completely collapsed in female foetus and
became as small spherical mass of dense connective tissue. In
male fetuses the mesonephros were regress and collapsed
during the second trimester
DISCUSSION The mesonephros of the dromedary camel foetus was
observed histologically at 0.9 cm CVRL as a narrow strip
along the roof of the thoracolumber region of the vertebral
column Aly (2007). Osman, Farouk, Eidaroos and Ahmed
(2008) observed it in the same region at 0.5 cm CVRL in the
dromedary camel. Several authors described the mammalian
mesonephrosi as mesonephric nephrons consisted of a
glomerulus-like body, a proximal tubule and a distal tubule
(Martino and Zamboni, 1966; Schiller and Tiedemann, 1981;
Tiedemann and Egerer, 1984; Smith and MacKay, 1991). In
the present study, the mesonephros of the dromedary camel
foetuses consisted of primary small glomeruli, secondary large
glomeruli (Giant glomeruli) and two types of tubules: 1-
Tubules lined with single layer of low cuboidal cells with
spherical central nuclei and clear lumen. 2-Tubules lined by
highly cuboidal cells with big spherical nuclei and their
luminal surface was studded with microvilli. In the dromedary
camel, these two types of mesonephric tubules were described
by Bareedy, Anis, Abbas, Ewais, and Amar (1982), Emara
(1989) and Aly (2007). Such morphology of mesonephric
tubules was also demonstrated in buffalo foetuses (Moustafa,
Enany, Osman and Amin,1986) and in human foetuses
(Sadler, 1995). In the present observations, the mesonephric
tubules of the dromedary camel foetus were oriented
dorsoventrally, similar to the observations of Upadhyay,
Luciani and Zamboni (1979) in the mouse foetuses. Upadhyay
and Zamboni (1982) described very large glomeruli occupied
the proximal third of sheep mesonephros and, according to its
size, was referred to as “giant glomeruli” as described by
Bremer (1916) and Davies and Davies (1950). Smith and
Mackay (1991) stated that, glomerulus-like structures were
found at some stages of development and consisted of
capillaries opposed to the ventral aspects of the tubules in
mouse foetuses. The S-shaped glomeruli in either degenerated
or remained as tubules were observed in mouse foetuses. In
the present findings in the dromedary camel fetuses, the large
glomeruli were limited in number (not more than 20) and
regressed when the gonads were differentiated, but new
generations of small mesonephric glomeruli in different stages
of development (“S” shape, “ɘ” comma shape and other
stages) remained till 17 cm CVRL (112 days of of age). This
observation may suggest a relation between the giant
glomeruli and the gonad differentiation or between the small
glomeruli and the developing metanephros.
The present observation may support the
suggestion of Ward, Cornillie, Erkens, Loo, Casteleyn,
Poucke, Burvenich, Hoorebeke, Ginneken, Peelman, and
Broeck (2010) who believe that the mesonephric glomeruli
continue to grow in porcine foetuses, even when the cranial
part of the mesonephros started to regress. These authors did
not mention whether these glomeruli were giant or small
glomeruli. This phenomenon may be explained by the fact that
the growing foetus requires a sufficiently large glomerular
filtration surface provided by small or large glomeruli. During
the development of the metanephros, the mesonephros of
porcine foetus continued to maintain its excretory function as
reported by Patten (1948). The giant glomerulus, which begins
at the first month of gestation in sheep foetuses, was
characterized by hypercellularity, thickening and obliteration
of the capillaries, and loss of Bowman’s capsule on the ventral
metanephros
mesonephros
ovary
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aspect of the glomerulus (Upadhyay and Zamboni,1982). In
the present study, the giant glomeruli had complete parietal
and visceral layers of Bowman’s capsule and the capillaries
were in the form of sinuses. Magras, Alifakiotis and
Pampoukidou (1997) reported that the existence of giant
glomeruli, a peculiar structure located dorsal to the genital
ridge in the cranial part of the mesonephros of the goat, must
play an important role in the gonadal development because
epithelial cells from mesonephric tubules and from the giant
glomeruli invaded the gonads. Upadhyay and Zamboni (1982)
observed an active mobilization of glomerular cells egress
from the giant glomerulus passing through the interruptions of
the Bowman’s capsule on its ventral aspect to the ovary and
testis in association with the germinal cells in sheep foetuses.
In the present study, the accumaltion of the large glomeruli
were connected to the gonads by dense connective tissue rich
in blood supply (mesogonadal ligament).
In the present investigation, the large
glomeruli (giant glomeruli) were observed near the gonads,
between 2and 3 cm CVRL (74 and 76 days of age) before the
time of gonads differentiation to male or female foetuses. The
giant glomeruli in male fetuses were surrounded the cranial
part of the mesonephros, while in the female foetuses were
near the hilus. It was clear from these observations that the
differentiation of the gonads of the dromedary camel foetuses
could be related according to the position of the gonads in
relation to the mesonephros and according to the position
where the giant glomeruli were arranged. In the present study,
the cranial part of the mesonephros had different way of
development and fate between male and female foetues. In
male fetuses, the cranial part of the mesonephros did not
separate from the mesonephros but it was transformed into
ductuli efferentes first, then other tubules and some giant
glomeruli contributed in the formation of the epididymis later.
The cranial part of the mesonephros in female foetues was
divided, and when the ovaries were developed this part
regressed and disappeared.
Sainio, Hellstedt, Kreidberg, Saxén and
Sariola (1997) reported that, in mice and rat, the cranial part of
the mesonephros was derived from the Wolffian duct and the
caudal tubules were derived from the mesonephric
mesenchyme. Consequently, it's possible to believe that the
hormone-dependence of mesonephros was only functioning in
the cranial part of mesonephric tubules of male foetuses after
the appearance of testes and release of its hormones. On the
other hand, the cranial part of the mesonephros disappeared in
female foetues and its may be due to anti hormones as it was
explained by the above authors and observed in the present
study.
In male foetuses of the dromedary camel
between 3 and 4 cm CVRL (74 and 76 days of age), in the
present investigation, the primitive ductuli efferentes were
observed in the cranial part of the mesonephros, the place
where the testes would develop and suspended by a short
mesogonadal ligament attached to the dorsal surface of the
mesonephros. The attachment between the mesonephros and
the developed testes contributed and required for the next step
of other mesonephric tubules transformation, Merchant-larios,
Moreno-mendoza' and Buehr (1993) explained this relation
between the mesonephros and testes. The differentiation of
Sertoli cells and Leydig cells proceeds in the absence of
mesonephros at early stages of development but endothelial
cells and peritubular myoid-like cells migrated into the
gonads, so they suggested that these cells might be
mesonephric cells required for seminiferous cord formation. In
the present observation, in female foetuses during the age
between 3 and 4 cm CVRL (74 and 76 days of age), the
ovaries were situated in the middle part of the medial border
of the mesonephros and connected to the hilus. Zolain (2011)
stated that in 22 cm CVRL (126 days of age) dromedary camel
foetus, the regressing mesonephros disappeared completely on
the left side, while in the right side it appeared like a small
prominence in the caudal pole of the right metanephros and
the left ovary differentiated earlier than the right one and was
separated from the mesonephros. This finding was in
agreement with the present finding and this result may explain
the increasing incidence of pregnancy in the left horn in adult
camels than the right one and that the left ovary may be more
active than the right ovary. The left mesonephros in female
foetuses was divided into cranial and caudal parts before the
right one and this is in coordination with the advanced ovarian
growth rate.
In dromedary camel foetus, Osman, Farouk,
Eidaroos and Ahmed (2008) reported that the mesonephros
began its regression from 3.7 cm CVRL. The regression
comprised apoptotic changes among the tubular and
glomerular elements of the mesonephros. However, Bareedy
(1982) stated that the mesonephros of dromedary camel
gradually degenerates from 5 cm CVRL, while Emara (1989)
reported that the mesonephric degeneration occurred at 3.8 cm
CVRL and El-Harairy, Gaber and Attia (1998) noticed that the
mesonephros started to degenerate at 15 cm CVRL, while, Aly
(2007) observed the degeneration at 4.7 mm CVRL.
The result of this study demonstrated that,
the signs of regression of the mesonephros were demonstrated
in female foetuses earlier than in male fetuses and the
regression signs began by large pale cells invaded the
capillaries between the mesonphric tubules in 7 cm CVRL(85
days of age). The giant glomeruli showed signs of regression
and degeneration after the gonads were differentiate in male
and female foetuses, whereas new generation of small
glomeruli were developed till the end of the first trimester in
male foetuses. The mesonephros regressed and disappeared
during the first trimester in female foetuses, whereas in male
foetuses it disappeared during the second trimester.
CONCLUSION
Mesonephros could be used as a guide in the gonads
differentiation to ovaries or testes before or at 3 cm CVRL (74
days of age) of dromedary camel foetus, grossly according to
the position of the gonads in relation to the mesonephros and
histological according to the position where the giant
glomeruli of the mesonephros were arranged.
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ACKNOWLEDGMENT
This work was carried out at the Department of
Anatomy Faculty of Veterinary Medicine, University of
Khartoum-Sudan, with financial support from the German
Academic Exchange Serves (DAAD).
REFERENCES [1] Aly, K. H. (2007). Development of the Mesonephros in Camel
(Camelus dromedarius). Anatomia Histologia Embryologia, 36(1): 58-
61
[2] Bareedy, M. H., Anis, H., Abbas, A. A., Ewais, M. S. S. and Ammar, S. M. S. (1982). Development of the mesonephros of the dromedary camel,
Research. Bull. 498, 1 – 22. Faculty of Agriculture, Zagazig University.
[3] Bremer, J. L. (1916). The interrelations of the mesonephros, kidney and placenta in different classes of animals. American Journal of Anatomy
19, 179-210.
[4] Davies, J. and Davies, D. V. (1950). The development of the mesonephros of the sheep. Proceedings of the Zoological Society 120,
73-93.
[5] El- Harairy, M. A., Gaber, A.A. and Attia, K. A. (1998). Prenatal
development of the camel (Camelus dromedarius) Kidney:
Morphogenesis of mesonephros. Journal of Camel Practice and
Research, 5 (1): 115-117. [6] Elwishy, A. B., Hemeida, N.A., Mobarak, O.A. M. and Elsayed, M.A.I.
(1981). Functional Changes in the Pregnant Camel with special
reference to Foetal Growth. Journal of Anatomy 137. [7] Emara, S. A. M. (1989). Prenatal development of the kidney of camel
(Camelus dromedarius). M.V.Sc. Thesis. Faculty of Veterinary
Medicine. Zagazig University. [8] Imam, H. M. A. (2005). Early Embryonic Development of the Camel
Metanephros. Assiut Veterinary Medical Journal; 51(106): 12-20.
[9] Magras, I.N., Alifakiotis,T. and Pampoukidou, A. (1997). The developmental relation among mesonephros, gonad and external
genitalia in the fetus of goat (Capra prisca). Anatomia. Histologia.
Embryolgia. 26, 195-197. [10] Martino, C. and Zamboni, L. (1966). A morphologic study of the
mesonephros of the human embryo. Journal of Ultrastructural Research.
16, 399-427.
[11] Merchant-larios, H., Moreno-mendoza, N. and Buehr, M. (1993). The
role of the mesonephros in cell differentiation and morphogenesis of the
mouse fetal testis. International Journal of Developmental Biology. 37: 407-4] 5
[12] Moustafa, I. A., Enany, E. E., Osman, A. K. and, Amin, M.E. (1986).
Development of the mesonephros of the Egyptian water buffalo. Alexandria Journal of Veterinary Science, 2 (1), 1 – 9.
[13] Musa, B.E. (1982). Studies on Kidney, Allantoic Fluid and Urine of
Camel (Camelus dromedarius). Sudan Journal of Veterinary Science and Animal Husbandry. 23(1): 118-121.
[14] Osman, A. H. K., Farouk, S. M., Eidaroos, H. and Ahmed, A. A. M.
(2008). Histogenesis of camel mesonephros (camelus dromedarius). Suez Canal Veterinary Medical Journal. Egypt, 13(2):377-386.
[15] Patten, B.M. (1948). Embryology of the Pig. 3rd Ed. New York. Toronto. London. McGraw-Hill
[16] Sadler, T. W. (1995). Urogenital system. In: Langman`s Medical
Embryology. 7th Edition, Baltimore. Philadelphia. Hong Kong. London. Munich.Sydney.Tokyo.Williams and Wilkins.
[17] Sainio, K., Hellstedt, P., Kreidberg, J.A., Saxén,L. and Sariola, H.
(1997). Differential regulation of two sets of mesonephric tubules by WT-1. Development 124, 1293-1299.
[18] Schiller, A. and Tiedemann, K. (1981). The mature mesonephric
nephron of the rabbit embryo. Cell and Tissue Review. 221, 431-442. [19] Smith, C. and MacKay, S. (1991). Morphological development and fate
of the mouse mesonephros. Journal of Anatomy. 174, 171 – 184.
[20] Tiedemann, K. and Egerer, G. (1984). Vascularization and glomerular ultrastructure in the pig mesonephros. Cell and Tissue Research. 238,
165-175
[21] Upadhyay, S., Luciani, J. M. and Zamboni, L. (1979). The role of the mesonephros in the development of indifferent gonads and ovaries of the
mouse. Ann. Biol. Anim. Bioch. Biophys.
[22] .Upadhyay, S. and Zamboni, L. (1982). Preliminary observations on the
role of the mesonephros in the development of the adrenal cortex. Anatomical Record 202, 105-111.
[23] Ward, D., Cornillie, P., Erkens, T., Loo, D. V., Casteleyn, C., Poucke,
M.V., Burvenich, C., Hoorebeke, L.V., Ginneken, C.V., Peelman, L. and Broeck,W.V.D. (2010). Expression and localization of angiogenic
growth factors in developing porcine mesonephric glomeruli. Journal of
Histochemistry and Cytochemistry. Volume 58(12): 1045–1056. [24] Zamboni, L. and Upadhyay, S. (1981). Ephemeral, rudimentary
glomerular structures in the mesonephros of the mouse. Anatomical
Record. 201, 641-644. [25] Zolain, Hidaia, B. (2011). Topography, Histogenesis and Histochemistry
of the Prenatal Ovary of the Camel (Camelus dromedarius). MVSc.
Thesis, Department of Anatomy, Faculty of Veterinary Medicine University of Khartoum, Sudan.
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