The harderian gland in the Wistar rat consists of tubules with wide lumina lined by a single laye... more The harderian gland in the Wistar rat consists of tubules with wide lumina lined by a single layer of columnar epithelial cells possessing myoepithelial cells within their basal laminae. The gland contains porphyrin pigment which is stored as solid intraluminal deposits. The glandular epithelium possesses 2 cell types, termed A and B. These are characterised by an extraordinarily well-developed tubular smooth endoplasmic reticulum and numerous lipid vacuoles. Type A cells can be distinguished from type B by the number, size and content of the lipid vacuoles. Type A cells are more numerous. They contain large lipid vacuoles with dense ribbon-like material identical in form to the material in the luminal masses of porphyrin pigment, whereas those of type B cells are small with crescentic dense lamellar material. The content of the vacuoles is essentially released by exocytosis, but holocrine secretion also occurs. The lipids and the ribbon-like material represent the bulk of the intra...
This study describes the structure of the harderian gland in desert rodents: 3 Gerbillidae specie... more This study describes the structure of the harderian gland in desert rodents: 3 Gerbillidae species (Gerbillus gerbillus, Meriones crassus, Psammomys obesus) and 1 Ctenodactylidae species (Ctenodactylus vali). In all these species the gland consists of tubules lined by a single layer of epithelial cells and possesses myoepithelial cells within their basal laminae. The gland contains porphyrin which is stored as solid intraluminal deposits. The glandular epithelium presents a single cell type (type I) in Psammomys obesus, 2 cell types (I and II) in Ctenodactylus vali and 3 (I, II and III) in Gerbillus gerbillus and Meriones crassus. The type I and II cells are columnar. They are characterised by many lipid vacuoles and a well developed vesicle-like structure of smooth endoplasmic reticulum. In Gerbillus gerbillus and Meriones crassus the type I cells can be distinguished from type II cells by cytoplasmic clefts approximately 1 micron in length. In Ctenodactylus vali type I cells are c...
Journal of physiology and pharmacology : an official journal of the Polish Physiological Society, 2010
The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic ra... more The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic rates. We have previously shown that continuous light exposure abolished the day/night variations of the delta-aminolevulinate synthase (ALA-S; the rate-limiting enzyme for porphyrin biosynthesis) gene expression observed under standard light: dark cycles (LD 12:12) in the rat HGs. This study was designed to examine whether the ALA-S changes were actually associated directly with light. The response of ferrochelatase (enzyme that converts protoporphyrin IX into heme) to light was also examined. Male Wistar rats were acclimatized to light: dark cycles regimen of 12:12 for 2 weeks. At the end of the 2 weeks, a 1 h-light pulse was applied in the middle of the dark phase. Animals were sacrificed immediately after the end of the light pulse. HGs were collected and stored at -80 degrees C until processed for quantitative RT-PCR. A 1 h-light pulse applied during mid-dark caused a significant incr...
The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic ra... more The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic rates. We have previously shown that continuous light exposure abolished the day/night variations of the delta-aminolevulinate synthase (ALA-S; the rate-limiting enzyme for porphyrin biosynthesis) gene expression observed under standard light: dark cycles (LD 12:12) in the rat HGs. This study was designed to examine whether the ALA-S changes were actually associated directly with light. The response of ferrochelatase (enzyme that converts protoporphyrin IX into heme) to light was also examined. Male Wistar rats were acclimatized to light: dark cycles regimen of 12:12 for 2 weeks. At the end of the 2 weeks, a 1 h-light pulse was applied in the middle of the dark phase. Animals were sacrificed immediately after the end of the light pulse. HGs were collected and stored at -80 degrees C until processed for quantitative RT-PCR. A 1 h-light pulse applied during mid-dark caused a significant increase of ALA-S gene expression (3-fold higher than in controls), whereas it was without effect on ferrochelatase gene expression. Our results suggest that light per se may regulate ALA-S gene expression in the rat HGs, and reveal that the ALA-S gene expression, and so heme biosynthesis, is under a photodynamic control.
This study investigates the release characteristics of atrial natriuretic peptide (ANP) from youn... more This study investigates the release characteristics of atrial natriuretic peptide (ANP) from young (10 weeks) and old (22 months) rat atrium. Levels of ANP release from samples of atrium were studied by organ perifusion. Rats were exposed to light:dark (LD) cycles of 12:12 or 18:6 and sacrificed at different zeitgeber time (ZT) points: ZT0, ZT6, ZT8, ZT12, ZT16, and ZT19 for LD 12:12 or ZT0, ZT9, ZT16, ZT18, ZT20, and ZT 21.5 for LD 18:6. The heart was collected, and the right atrium was removed, weighed, and perifused with Krebs-bicarbonate buffer for 100 min, including a period of 50 min for stabilization of secretion rate. ANP concentrations released by atrium did not differ between the two age groups either under LD 12:12 or under LD 18:6, except at the light:dark transition under LD 12:12 conditions where ANP levels were significantly (P<0.05) lower in young compared to old rats. ANP exhibited daily variations in concentrations under LD 12:12, with a peak during the beginning of photophase (ZT0) in young rats and a peak at the beginning of scotophase (ZT12) in old animals. These variations were strongly modified under LD 18:6, where the pattern of the release exhibited a peak during the light phase at ZT16 in both young and old rats. This strongly suggests that the atrial ANP rhythm is dependent on the environmental light:dark cycle. Moreover, the total ANP levels released by atria in old rats were significantly increased under LD 18:6 compared to standard LD 12:12. This observation strongly suggests that old animals are more sensitive to a photoperiodic change. In conclusion, our results show that ANP concentrations in the rat atrium exhibit daily variations which are significantly affected by the daylength (photoperiod) change in aged rats.
The Harderian glands of six rodents (the Wistar rat, the gerbils Psammomys obesus, Gerbillus gerb... more The Harderian glands of six rodents (the Wistar rat, the gerbils Psammomys obesus, Gerbillus gerbillus, Meriones crassus, and Meriones lybicus, and the gundi, Ctenodactylus vali) were investigated by means of light and transmission electron microscopy. In rodents, the Harderian gland consists of branching tubules, lined by a single layer of epithelial cells and possessing myoepithelial cells within their basal lamina. The Harderian gland contains porphyrins, stored as intraluminal masses. The glandular epithelium presents a single cell type (I) in Psammomys obesus, two cell types (I, II) in Ctenodactylus vali and the Wistar rat, and three cells types (I, II, III) in Gerbillus gerbillus, M. crassus, and M. lybicus. The type I and II cells are columnar, characterized by lipid vacuoles and well-developed profiles of the smooth endoplasmic reticulum. In Meriones and Gerbillus, the type I cell can be distinguished from the type II cell by cytoplasmic clefts. In Ctenodactylus vali, the type I cell is characterized by cytoplasmic rod-shaped crystalloid structures. These structures are also present in the sole cell type of Psammomys obesus. In the Wistar rat, the two cell types are distinguished by the number and the size of the lipid vacuoles. The content of the vacuole is released primarily by exocytosis, but holocrine and apocrine secretion was also noted. The type III cell is pyramidal, characterized by numerous mitochondria, and has an extraordinarily well-developed granular endoplasmic reticulum organized in concentric lamellae in Gerbillus gerbillus. The single excretory duct begins at the hilus. Mast cells, plasma cells, macrophages, fenestrated capillaries, and unmyelinated nerve endings with clear or dense-cored vesicles are present in the connective tissue. Melanocytes are predominant in the gland interstices of Psammomys obesus. The gland is surrounded by a thin connective tissue capsule, covered with the endothelium of the orbital venous sinus.
The pineal gland contains many peptides known to be implicated in melatonin production. We examin... more The pineal gland contains many peptides known to be implicated in melatonin production. We examined the effects of a synthetic pineal tetrapeptide Ala-Glu-Asp-Gly on melatonin secretion by the pineal gland. The tetrapeptide effects on pineal gland melatonin secretion were studied in young (9 weeks) and old (27 months) male Wistar rats using a perifusion device. Pineal tetrapeptide at the concentrations used (10(-4) to 10(-6) M) had no significant effect upon melatonin secretion whatever the age of the animals, young or old. We also looked at the effect of the tetrapeptide on pineal melatonin stimulated by a beta-adrenergic agonist, isoproterenol. We found that isoproterenol-induced melatonin increase was not modified by the tetrapeptide. Our results suggest that the pineal tetrapeptide Ala-Glu-Asp-Gly, does not seem to play a role, at least in vitro, in the control of melatonin secretion by the rat pineal gland.
There have been few studies on fungal infection of the foot in military personnel. The aim of thi... more There have been few studies on fungal infection of the foot in military personnel. The aim of this study was to determine the prevalence and aetiological factors of superficial mycoses of the foot in military personnel attending the Department of Dermatology of the Army Central Hospital in Algiers, Algeria. A complete dermatological examination was performed in 650 male military personnel. Cultures of skin and nail specimens of the feet were performed for each participant. Fungal infection of the foot (including tinea pedis and Candida interdigital infection) was clinically diagnosed in 147, and confirmed in 119 by positive cultures, resulting in a total prevalence of 18.3%. When subjects were grouped according to military rank, fungal infection of the foot was prevalent in troop soldiers; when grouped according to years of service to the army, the infection was frequent in military recruits. The dermatophyte species Trichophyton rubrum (20.9%) and the yeast species Candida parapsilosis (18.7%) were shown to be the major causal agents isolated. Tinea pedis and Candida interdigital infection are the most prevalent (68%) superficial fungal infections among Algerian military personnel.
The aims of the current investigation were (1) to establish an efficient procedure for the isolat... more The aims of the current investigation were (1) to establish an efficient procedure for the isolation of rodent harderian gland cells and to define conditions for maintenance of viable differentiated cells; (2) to compare the in vitro growth pattern of cultured epithelial cells; and (3) to ...
The harderian gland in the Wistar rat consists of tubules with wide lumina lined by a single laye... more The harderian gland in the Wistar rat consists of tubules with wide lumina lined by a single layer of columnar epithelial cells possessing myoepithelial cells within their basal laminae. The gland contains porphyrin pigment which is stored as solid intraluminal deposits. The glandular epithelium possesses 2 cell types, termed A and B. These are characterised by an extraordinarily well-developed tubular smooth endoplasmic reticulum and numerous lipid vacuoles. Type A cells can be distinguished from type B by the number, size and content of the lipid vacuoles. Type A cells are more numerous. They contain large lipid vacuoles with dense ribbon-like material identical in form to the material in the luminal masses of porphyrin pigment, whereas those of type B cells are small with crescentic dense lamellar material. The content of the vacuoles is essentially released by exocytosis, but holocrine secretion also occurs. The lipids and the ribbon-like material represent the bulk of the intra...
This study describes the structure of the harderian gland in desert rodents: 3 Gerbillidae specie... more This study describes the structure of the harderian gland in desert rodents: 3 Gerbillidae species (Gerbillus gerbillus, Meriones crassus, Psammomys obesus) and 1 Ctenodactylidae species (Ctenodactylus vali). In all these species the gland consists of tubules lined by a single layer of epithelial cells and possesses myoepithelial cells within their basal laminae. The gland contains porphyrin which is stored as solid intraluminal deposits. The glandular epithelium presents a single cell type (type I) in Psammomys obesus, 2 cell types (I and II) in Ctenodactylus vali and 3 (I, II and III) in Gerbillus gerbillus and Meriones crassus. The type I and II cells are columnar. They are characterised by many lipid vacuoles and a well developed vesicle-like structure of smooth endoplasmic reticulum. In Gerbillus gerbillus and Meriones crassus the type I cells can be distinguished from type II cells by cytoplasmic clefts approximately 1 micron in length. In Ctenodactylus vali type I cells are c...
Journal of physiology and pharmacology : an official journal of the Polish Physiological Society, 2010
The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic ra... more The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic rates. We have previously shown that continuous light exposure abolished the day/night variations of the delta-aminolevulinate synthase (ALA-S; the rate-limiting enzyme for porphyrin biosynthesis) gene expression observed under standard light: dark cycles (LD 12:12) in the rat HGs. This study was designed to examine whether the ALA-S changes were actually associated directly with light. The response of ferrochelatase (enzyme that converts protoporphyrin IX into heme) to light was also examined. Male Wistar rats were acclimatized to light: dark cycles regimen of 12:12 for 2 weeks. At the end of the 2 weeks, a 1 h-light pulse was applied in the middle of the dark phase. Animals were sacrificed immediately after the end of the light pulse. HGs were collected and stored at -80 degrees C until processed for quantitative RT-PCR. A 1 h-light pulse applied during mid-dark caused a significant incr...
The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic ra... more The rodent Harderian glands (HGs) are large paired orbital organs with highest porphyrinogenic rates. We have previously shown that continuous light exposure abolished the day/night variations of the delta-aminolevulinate synthase (ALA-S; the rate-limiting enzyme for porphyrin biosynthesis) gene expression observed under standard light: dark cycles (LD 12:12) in the rat HGs. This study was designed to examine whether the ALA-S changes were actually associated directly with light. The response of ferrochelatase (enzyme that converts protoporphyrin IX into heme) to light was also examined. Male Wistar rats were acclimatized to light: dark cycles regimen of 12:12 for 2 weeks. At the end of the 2 weeks, a 1 h-light pulse was applied in the middle of the dark phase. Animals were sacrificed immediately after the end of the light pulse. HGs were collected and stored at -80 degrees C until processed for quantitative RT-PCR. A 1 h-light pulse applied during mid-dark caused a significant increase of ALA-S gene expression (3-fold higher than in controls), whereas it was without effect on ferrochelatase gene expression. Our results suggest that light per se may regulate ALA-S gene expression in the rat HGs, and reveal that the ALA-S gene expression, and so heme biosynthesis, is under a photodynamic control.
This study investigates the release characteristics of atrial natriuretic peptide (ANP) from youn... more This study investigates the release characteristics of atrial natriuretic peptide (ANP) from young (10 weeks) and old (22 months) rat atrium. Levels of ANP release from samples of atrium were studied by organ perifusion. Rats were exposed to light:dark (LD) cycles of 12:12 or 18:6 and sacrificed at different zeitgeber time (ZT) points: ZT0, ZT6, ZT8, ZT12, ZT16, and ZT19 for LD 12:12 or ZT0, ZT9, ZT16, ZT18, ZT20, and ZT 21.5 for LD 18:6. The heart was collected, and the right atrium was removed, weighed, and perifused with Krebs-bicarbonate buffer for 100 min, including a period of 50 min for stabilization of secretion rate. ANP concentrations released by atrium did not differ between the two age groups either under LD 12:12 or under LD 18:6, except at the light:dark transition under LD 12:12 conditions where ANP levels were significantly (P<0.05) lower in young compared to old rats. ANP exhibited daily variations in concentrations under LD 12:12, with a peak during the beginning of photophase (ZT0) in young rats and a peak at the beginning of scotophase (ZT12) in old animals. These variations were strongly modified under LD 18:6, where the pattern of the release exhibited a peak during the light phase at ZT16 in both young and old rats. This strongly suggests that the atrial ANP rhythm is dependent on the environmental light:dark cycle. Moreover, the total ANP levels released by atria in old rats were significantly increased under LD 18:6 compared to standard LD 12:12. This observation strongly suggests that old animals are more sensitive to a photoperiodic change. In conclusion, our results show that ANP concentrations in the rat atrium exhibit daily variations which are significantly affected by the daylength (photoperiod) change in aged rats.
The Harderian glands of six rodents (the Wistar rat, the gerbils Psammomys obesus, Gerbillus gerb... more The Harderian glands of six rodents (the Wistar rat, the gerbils Psammomys obesus, Gerbillus gerbillus, Meriones crassus, and Meriones lybicus, and the gundi, Ctenodactylus vali) were investigated by means of light and transmission electron microscopy. In rodents, the Harderian gland consists of branching tubules, lined by a single layer of epithelial cells and possessing myoepithelial cells within their basal lamina. The Harderian gland contains porphyrins, stored as intraluminal masses. The glandular epithelium presents a single cell type (I) in Psammomys obesus, two cell types (I, II) in Ctenodactylus vali and the Wistar rat, and three cells types (I, II, III) in Gerbillus gerbillus, M. crassus, and M. lybicus. The type I and II cells are columnar, characterized by lipid vacuoles and well-developed profiles of the smooth endoplasmic reticulum. In Meriones and Gerbillus, the type I cell can be distinguished from the type II cell by cytoplasmic clefts. In Ctenodactylus vali, the type I cell is characterized by cytoplasmic rod-shaped crystalloid structures. These structures are also present in the sole cell type of Psammomys obesus. In the Wistar rat, the two cell types are distinguished by the number and the size of the lipid vacuoles. The content of the vacuole is released primarily by exocytosis, but holocrine and apocrine secretion was also noted. The type III cell is pyramidal, characterized by numerous mitochondria, and has an extraordinarily well-developed granular endoplasmic reticulum organized in concentric lamellae in Gerbillus gerbillus. The single excretory duct begins at the hilus. Mast cells, plasma cells, macrophages, fenestrated capillaries, and unmyelinated nerve endings with clear or dense-cored vesicles are present in the connective tissue. Melanocytes are predominant in the gland interstices of Psammomys obesus. The gland is surrounded by a thin connective tissue capsule, covered with the endothelium of the orbital venous sinus.
The pineal gland contains many peptides known to be implicated in melatonin production. We examin... more The pineal gland contains many peptides known to be implicated in melatonin production. We examined the effects of a synthetic pineal tetrapeptide Ala-Glu-Asp-Gly on melatonin secretion by the pineal gland. The tetrapeptide effects on pineal gland melatonin secretion were studied in young (9 weeks) and old (27 months) male Wistar rats using a perifusion device. Pineal tetrapeptide at the concentrations used (10(-4) to 10(-6) M) had no significant effect upon melatonin secretion whatever the age of the animals, young or old. We also looked at the effect of the tetrapeptide on pineal melatonin stimulated by a beta-adrenergic agonist, isoproterenol. We found that isoproterenol-induced melatonin increase was not modified by the tetrapeptide. Our results suggest that the pineal tetrapeptide Ala-Glu-Asp-Gly, does not seem to play a role, at least in vitro, in the control of melatonin secretion by the rat pineal gland.
There have been few studies on fungal infection of the foot in military personnel. The aim of thi... more There have been few studies on fungal infection of the foot in military personnel. The aim of this study was to determine the prevalence and aetiological factors of superficial mycoses of the foot in military personnel attending the Department of Dermatology of the Army Central Hospital in Algiers, Algeria. A complete dermatological examination was performed in 650 male military personnel. Cultures of skin and nail specimens of the feet were performed for each participant. Fungal infection of the foot (including tinea pedis and Candida interdigital infection) was clinically diagnosed in 147, and confirmed in 119 by positive cultures, resulting in a total prevalence of 18.3%. When subjects were grouped according to military rank, fungal infection of the foot was prevalent in troop soldiers; when grouped according to years of service to the army, the infection was frequent in military recruits. The dermatophyte species Trichophyton rubrum (20.9%) and the yeast species Candida parapsilosis (18.7%) were shown to be the major causal agents isolated. Tinea pedis and Candida interdigital infection are the most prevalent (68%) superficial fungal infections among Algerian military personnel.
The aims of the current investigation were (1) to establish an efficient procedure for the isolat... more The aims of the current investigation were (1) to establish an efficient procedure for the isolation of rodent harderian gland cells and to define conditions for maintenance of viable differentiated cells; (2) to compare the in vitro growth pattern of cultured epithelial cells; and (3) to ...
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Papers by Y. Djeridane