Hikmet Altunay

Nasal administration of metoclopramide from different dosage forms: in vitro, ex vivo, and in vivo evaluation

Nasal drug delivery is an interesting route of administration for metoclopramide hydrochloride (MTC) in preventing different kind of emesis. Currently, the routes of administration of antiemetics are oral or intravenous, although patient compliance is often impaired by the difficulties associated with acute emesis or invasiveness of parenteral administration. In this perspective, nasal dosage forms (solution, gel, and lyophilized powder) of MTC were prepared by using a mucoadhesive polymer sodium carboxymethylcellulose (NaCMC). In vitro and ex vivo drug release studies were performed in a modified horizontal diffusion chamber with cellulose membrane and excised cattle nasal mucosa as diffusion barriers. The tolerance of nasal mucosa to the formulation and its components were investigated using light microscopy. In vivo studies were carried out for the optimized formulations in sheep and the pharmacokinetics parameters were compared with oral solution and IV dosage form. The release of MTC from solution and powder formulations was found to be higher than gel formulation (p < 0.05). Histopathological examination did not detect any severe damage. Hydroxypropyl-β-cyclodextrin (HPβCD) used in powder formulations was found to be effective for enhancing the release and absorption of MTC. In contrast to in vitro and ex vivo experiments nasal bioavailability of gel is higher than those of solution and powder (p < 0.05). In conclusion, the NaCMC gel formulation of MTC with mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.

The fine structure of the Harderian gland in the ostrich (Struthio camelus).

The Harderian gland of the ostrich (Struthio camelus) is a tubuloalveolar gland containing holocrine secreting epithelial cells. The gland epithelium is composed of two different cell types, which can be classified as type I and type II. These cells contain dense secretory vesicles in their cytoplasm and they are connected laterally with desmosomes. At the basal site of these cells, myoepithelial cells are present. Plasma cells are observed in the subepithelial region of the gland. In the interlobular trabeculae, forming the gland stroma, fibroblasts, blood vessels and nerve fibres are included. Another important finding in the ostrich Harderian gland is the presence of homogeneous material.

Fine structure of the retinal pigment epithelium, Bruch's membrane and choriocapillaris in the horse.

The morphology of the retinal pigment epithelium (RPE) and closely associated Bruchs membrane and choriocapillaris was investigated by light and transmission electron microscopy in the camel (Camelus dromedarius). The study showed that RPE is composed of a single layer of hexanocuboidal cells that were joined laterally by a series of apically located tight junctions. In addition, adjacent from internal side of cell membrane at the level of tight junctions, an undefined structure which resembled the myofibrillar organization of skeletal muscles in appearance was located. These cells displayed numerous short basal infoldings and abundant thin apical processes which enclosed the rod outer segments. The epithelial cell nuclei were large, vesicular and eccentrically located. Within the epithelial cells, smooth endoplasmic reticulum was very abundant, while rough endoplasmic reticulum was present only in small amounts. Polysomes were also numerous and the mitochondria often displayed a ring‐shaped structure. Lipofuscin granules were plentiful in all locations. Bruchs membrane (complexus basalis) was typically pentalaminate throughout the retina. The endothelium of the choriocapillaris facing Bruchs membrane was extremely thin and heavily fenestrated. These fenestrations displayed typical single‐layered diaphragm as noted in most species.

Distribution and morphometry of fiber types in cremaster muscles of boys with inguinal hernia or undescended testis

In the present study, we determined and compared the distribution and mean diameters of fiber in the cremaster muscles (CM) of boys with either inguinal hernia (IH) or undescended testis (UT). Samples of CM were obtained from 20 patients (10 boys with IH, and 10 boys with UT) of similar age. The CM muscles of two boys each, without inguinal pathology, were sampled during autopsy. Sections were stained for oxidative and glycolytic enzymes, as well as for ATP-ase reactions after acid (pH: 4.6) and alkaline (pH: 10.6) preincubations. Specimens were also analyzed morphometrically using a KONTRON 400 computerized image analysis system. The Mann- Whitney U test was applied to compare the percentages of fiber types and mean diameters of fibers according to the types of the CM of boys with IH or UT. In boys, the CM is mainly composed of type 1 fibers. The CMs of patients with UT reveal alterations of neurogenic origin. Although both type 1 and type 2 fibers reveal alterations, type 2 fibers appear to be affected more profoundly and characterized by significantly decreased mean diameters. Significantly decreased mean diameters of type 2 fibers in CM may support disuse, lack of sensitivity to the hormonal influences, or an alteration in the corticospinal tracts of boys with UT.

Biomechanical and histological outcome of combined raloxifene–estrogen therapy on skeletal and reproductive tissues

Estrogen replacement is a potent therapy for postmenopausal osteoporosis. However, its carcinogenic effects on breasts and the uterus limit its utilization. Raloxifene has estrogen-like effects on bones without the carcinogenic symptoms on breast or uterine tissue. Their individual effects are well characterized, but the results of their interaction remains elusive. In this work, we investigate the consequences of a combined raloxifene/estrogen therapy on bone and uterus with experimental osteoporosis. 40 Wistar rats began treatment 3 months post-ovariectomy. Estrogen and raloxifene were administered 0.03 mg/kg/day and 1.5mg/kg/day separately and together for 5 times per week for 12 weeks. Biomechanical tests and bone mineral density measurements, histology of uterus, and blood markers were analyzed. The co-administration group had higher toughness and ultimate strength than the ovariectomized controls (P<0.01). E+R had better biomechanical properties than the single treatments; yet the differences were not significant. Uterus histology signified high degeneration in the estrogen group. The raloxifene group had less degeneration but higher vascularization. Less immune reaction and vascularization were observed in the group with combined dosage than in those with individual treatments. Hence, the uterus of the combined treatment had fewer side effects than the ones that were individually treated. Mutual antagonization might be possible between raloxifene and estrogen, and that might have caused a decrease in the adverse effects. Overall, combined therapy might be useful to minimize the individual side effects of raloxifene and estrogen on the uterus and still provide bone strength and toughness.

Prospective evaluation of Vitamin K2, Raloxifene and their co-administration in osteoporotic rats

In this study, therapeutic effects of Vitamin K2, Raloxifene and their co-administration on bone, uterus, blood and weight profiles were investigated with an ovariectomized rat model. Forty Wistar rats were divided into five groups (n=8): Raloxifene (R), Vitamin K2 (K), Raloxifene+Vitamin K2 (R+K), ovariectomized controls (OVX) and Sham-operated controls (Sham). Treatment began 3 months after ovariectomy. Vitamin K2 and Raloxifene were administered 30 and 1.5 mg/kg/day separately and in combination five times per week for 12 weeks. All treatment groups had significantly higher ultimate strength and energy absorption capacity (P<0.05) than ovariectomized controls in both femur and tibia. Histological results showed that treatment groups had healthy lumen structure, whereas OVX had degeneration. Adverse effects which were seen in individual treatments (myometrium weakening in K, endometrium weakening in R, and ALP increase in group R) were not observed in the R+K group implying a synergistic effect of these two agents when they are co-administered. According to blood analysis, ALP values were significantly high in Raloxifene-only group (P<0.0001). This effect is suppressed in the co-administered group. In summary, the groups R, K and R+K had significantly higher ultimate strength and less susceptibility to fracture than ovariectomized controls. In summation, Vitamin K2 treated groups (either in single or combined with Raloxifene) had considerable biomechanical performance and reproductive tissue profile indicating that this agent is prospectively effective in osteoporosis management.

Determination of acid alpha-naphthyl acetate esterase enzyme activity in peripheral blood leukocytes of gazelles (Gazella subgutturosa).

We examined gazelle peripheral blood leucocytes using the α-Naphthyl acetate esterase (ANAE) staining technique (pH 5.8). Our purpose was to determine the percentage of ANAE positive lymphocytes. The proportion of ANAE positive T-lymphocytes was 72%. T-lymphocytes showed an ANAE positive reaction, but eosinophilic granulocytes and monocytes also showed a positive reaction. By contrast, no reaction was detected in B-lymphocytes, neutrophil granulocytes or platelets. The reaction observed in T-lymphocytes was a red-brown coloration, usually 1–2 granules, but enough granules to fill the cytoplasm were detected rarely. As a result of ANAE enzyme staining, we concluded that the staining technique can be used as a cytochemical marker for gazelle T-lymphocytes.

Fine Structure of the Retinal Pigment Epithelium, Bruch's Membrane and Choriocapillaris in the Ostrich (Struthio camelus)

The fine structure of the retinal pigment epithelium (RPE), Bruchs membrane and choriocapillaris in the ostrich (Struthio camelus) was investigated by using light microscopy and transmission electron microscopy. In this species, the RPE consisted of a single layer of low columnar cells. The epithelial cells were joined laterally by two type junctions, zonulae occludentes and zonulae adherentes located in the midregion of the cells. These cells displayed numerous deep basal infoldings and thick extensive apical processes, which enclosed the outer segments of the rods. The epithelial cell nuclei were large, vesicular and located basally within the epithelial cells. Smooth endoplasmic reticulum was very abundant, while rough endoplasmic reticulum was scarce. Mitochondria of various shapes were abundant basally while polysomes were plentiful and widespread. In the light‐adapted state melanosomes were located in the apical region and in apical processes of the epithelial cells. Myeloid bodies were large, numerous and often showed ribosomes on their outer surface. Bruchs membrane (complexus basalis) was typical pentalaminate throughout the retina, as noted in the majority of other vertebrates. The endothelium of the choriocapillaris facing Bruchs membrane was extremely thin but only moderately fenestrated. Some of the fenestrations displayed a double‐layered diaphragm while the majority showed the more typical single‐layered diaphragm noted in most species.

Expression pattern of galectin-1 and galectin-3 in rat testes and epididymis during postnatal development

Galectins are a family of lectins-binding beta-galactosides involved in a variety of extracellular and intracellular processes, thereby contributing to homeostasis, cell adhesion, cellular turnover, and immunity. This study aimed to determine the localization and expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) in the testis and epididymis of rats at postnatal [(prepubertal (day 5), pubertal (day 20), postpubertal (day 50) and mature (day 70)] periods by using immunohistochemistry and Western blotting. Gal-1 and Gal-3 were differentially expressed in different types of cells in the testis and epididymis during postnatal development. While we detected Gal-1 expression in some spermatogenic cells and Leydig cells in the testis, not in the epididymal epithelium, Gal-3 was expressed in Sertoli cells, peritubular myoid cells, Leydig cells, smooth muscles and interstitial CD68-positive macrophages. Epithelial cells of the corpus and cauda epididymis showed an intense Gal-3 expression. Gal-1 expression was higher in the testis than in the epididymis on days 50 and 70. The expression of Gal-3 in the testis increased from the prepubertal to mature period. While the expression difference of Gal-3 was not statistically significant in the testis and epididymis until puberty, Gal-3 expression in the postpubertal and mature periods was higher in the epididymis. The expression of Gal-3 in the corpus and cauda epididymis was higher than that in the caput epididymis. In conclusion, our findings suggest that puberty has potential regulatory effect on the expression of galectins in testis and epididymis of rats. Gal-1 and 3 may play a role in the development of the reproductive system and the preservation of the immune-privileged environment in the testis, due to their pro-apoptotic and anti-apoptotic functions. The presence of intense expression of Gal-3 in the corpus and cauda epididymis may contribute to the maturation and storage of spermatozoa.

The structure of bursa of Fabricius in the long-legged buzzard (Buteo rufinus): histological and histochemical study.

Abstract The bursa of Fabricius (BF) is a lymphoepithelial organ found only in birds. Differences in morphology of BF could play an important role in immune response. The objective of this study was to investigate the histological and histochemical characteristics of the bursa of Fabricius in the long-legged buzzard (Buteo rufinus). The material for the study comprised bursa samples obtained from three long-legged buzzards with permission of the General Directorate of Nature Protection and National Parks (Ankara, Turkey). Briefly, interfollicular epithelium (IFE) was shown to be columnar in shape and not to contain goblet cells. Reticular fibers were located in interfollicular septae. Each lymphoid follicle in the bursa of Fabricius in the long-legged buzzard was remarkably linked to the follicle associated epithelium (FAE). Namely, FAE has been reported to stimulate antibody production by transferring antigens to the medulla and have a leading role in developing of local immune response. Among the others, the species-specific differences in bursa of Fabricius morphology of long-legged buzzard (Buteo rufinus) also might support the continuity of this species in nature.