Search PubMed⌕ Search

Biomedical subjects

D Dayan

Publications and source records attributed to D Dayan.

At least 19 recordsLinked to original sources
PubMed2000

Sarcomatoid salivary duct carcinoma of the parotid gland.

Salivary duct carcinoma (SDC) is a high-grade neoplasm known to histologically resemble high-grade ductal carcinoma in situ of the breast. We describe 3 cases of sarcomatoid salivary duct carcinoma, a heretofore unreported variant of SDC. Each case was a composite of SDC and sarcomatoid carcinoma and histologically similar to reported cases arising in the breast. The clinicopathologic features, including immunohistochemistry, of 3 cases were investigated. In the 3 men, ages 56, 68, and 70 years, the resected parotid tumors measured 1.5, 3.5, and 1.5 cm, respectively. Only the 3.5-cm tumor extended beyond the parotid gland into soft tissue. This patient died at 3 years with pulmonary metastases. The other patients were free of disease at 6 and 12 months. Histologically, each case was a composite of usual-type SDC and sarcomatoid carcinoma. SDC showed typical cribriform architecture, whereas anaplastic, spindled cells constituted the sarcomatoid areas. Immunohistochemically, epithelial elements stained as follows: cytokeratin (AE1/AE3 & CAM 5.2) positive in 3 of 3 cases, EMA positive in 3 of 3 cases, vimentin negative in 3 of 3 cases, desmin negative in 3 of 3 cases, c-erbB-2 positive in 1 of 2 cases. Sarcomatoid elements stained as follows: AE1/AE3 negative in 3 of 3 cases, CAM 5.2 rare positive cell in 1 of 3 cases, EMA focally positive in 3 of 3 cases, vimentin positive in 3 of 3 cases, desmin negative in 3 of 3 cases, c-erbB-2 negative in 2 of 2 cases. Electron microscopy, performed in one case, showed scattered junctional complexes congruent with epithelial differentiation. Immunohistochemical results, EMA and CAM 5.2 positivity, and ultrastructural findings supported our belief that these unique biphasic tumors represented SDC with sarcomatoid carcinoma. We conclude an element of sarcomatoid carcinoma rarely may arise in association with SDC, and it is erroneous to diagnose such tumors as "carcinosarcoma."

Aged↗
PubMed2000

Aging of human palatal salivary glands: a histomorphometric study.

The aim of the present study was to examine age-related changes in the parenchymal and stromal components of palatal salivary glands of healthy subjects. Palatal salivary gland biopsies were obtained from 120 autopsies and were divided into young, adult, and old age groups. Histomorphometric measurements were performed on hematoxylin and eosin (H&E) stained slides. Parenchymal components included acini and ducts, and stromal components included connective tissue, blood and lymphatic vessels, inflammatory infiltrate, and adipose tissue. The mean volume fraction of each component in each age group was calculated. Statistical analysis was performed by one-way ANOVA and Tamhane tests. The mean volume fraction of the acinar component demonstrated a significant age-related decrease of 48% (P < 0.001). The mean volume fractions of the ducts and of all the stromal components demonstrated a significant age-related increase (P < 0. 001). The inflammatory infiltrate component had the highest increase with aging (1471%), followed by the ducts (177%), blood and lymphatic vessels (138%), adipose tissue (130%), and connective tissue (60%). These age-related changes, the first to be reported in palatal salivary glands from healthy subjects, are different from those described in the labial salivary glands, especially in regard to the significant increase in the parenchymal ductal component, as well as in the stromal inflammatory infiltrate and adipose tissue components. It can be suggested that these changes could have important implications regarding the age-related function of these glands.

Adolescent↗
PubMed2000

Porous bovine bone mineral in healing of human extraction sockets. Part 1: histomorphometric evaluations at 9 months.

BACKGROUND: Extraction socket wound healing is characterized by resorption of the alveolar bone at the extraction site. This produces a decrease in ridge volume, deformations of ridge contours, and, thus, difficulties in delayed placement of root-form implants in an ideal position. Cancellous porous bovine bone mineral (PBBM) applied to fresh extraction sockets has recently been proposed to minimize the reduction in ridge volume. The aim of this study was to investigate the influence of PBBM grafted particles on the histopathologic pattern of the intrasocket regenerated bone and to evaluate histomorphometrically the healed PBBM grafted extraction socket site at 9 months' post-extraction. METHODS: PBBM particles (250 to 1,000 microns in size) were grafted in 15 fresh human extraction sockets in 15 patients. Socket wall bone height was measured from the crestal ridge level before the mineral particles were inserted. Primary soft tissue closure was performed to protect the grafted particles via a pediculated split palatal flap. At 9 months, socket bone walls were remeasured and cylinder bone samples of the previously PBBM-grafted sites were obtained. Decalcified specimens were sectioned at a cross-horizontal plane and stained with hematoxylin and eosin for histopathologic and histomorphologic examination. Tissue area percentage of bone, PBBM, and connective tissue (CT) was calculated for each specimen from the crestal to the apical region and changes in values compared. RESULTS: Average clinical overall bone fill of the augmented socket sites was 82.3%. Histologically, PBBM particles were observed in all specimens. Newly formed bone was characterized by abundance of cellular woven-type bone in the coronal area, while lamellar arrangements could be identified only in the more apical region. New osseous tissue adhered to the PBBM. Histomorphometric measurements showed an increase of mean bone tissue area along the histological sections from 15.9% in the coronal part to 63.9% apically (average 46.3%). CT fraction decreased from 52.4% to 9.5% (average 22.9%) from the crestal to the apical region. PBBM area fraction varied from 26.4% to 35.1% (average 30.8%). Statistical analysis of the comparison between areas of bone, CT, and PBBM was performed in different points along the coronal-apical axis. Differences were significant (P <0.01) at the most crestal, middle, and apical section cut areas, but not at the cervical section cuts. Bone area fraction increased in the apical direction as much as CT correlatively decreased. Unlike CT and bone, PBBM retained constant relative volume (approximately 30%), regardless of the depth of the specimen cores. CONCLUSIONS: PBBM particles are an appropriate biocompatible bone derivative in fresh extraction sockets for ridge preservation. The resorbability of this xenograft could not be recognized in a 9-month period. Further investigation is needed to clarify the resorptive mechanisms of PBBM.

Adult↗
PubMed2000

Spontaneous early exposure of submerged implants: II. Histopathology and histomorphometry of non-perforated mucosa covering submerged implants.

BACKGROUND: Spontaneous early exposure is a complication that could account for significant interference during the early healing phase of dental implants. Spontaneous perforations of the mucosa covering implants have been classified according to the degree of implant exposure from 0 (no perforation) to IV (complete exposure). In this study, the characteristics of the epithelium and connective tissue of clinically non-perforated mucosa over submerged implants are histologically and histomorphometrically evaluated. METHODS: Ten randomly selected tissue disks of intact (Class [Cl]-0) mucosa covering submerged implants were removed using a biopsy punch. Identical mucosal punch specimens were obtained from edentulous sites treated by non-submerged (1-stage) implants for use as controls. Specimens were histopathologically examined. The epithelial width and inflammatory infiltrate adjacent to the epithelium were histomorphometrically measured and the data statistically analyzed. RESULTS: Non-perforated mucosa covering the submerged implants (Cl-0) was characterized by an inflammatory fibro-epithelial hyperplasia. In 70% of Cl-0 hematoxylin and eosin-stained sections, there was mineralized material in the connective tissue, mostly sequestra. The epithelial width was 1.5 times higher (0.553 +/- 0.187 mm) when compared to controls (0.345 +/- 0.129 mm; P <0.0001). Concomitantly, the chronic inflammatory infiltrate was almost double in Cl-0 specimens (1,411 +/- 617 cell/mm2) when compared to controls (833 +/- 275 cells/mm2; P<0.001). A positive correlation between the linear combination of the epithelial width and the linear combination of the inflammatory cell concentration was found in both groups: Cl-0: r = 0.669, P= 0.0001; control: r = 0.541, P= 0.005. CONCLUSIONS: Different factors may result in the formation of spontaneous early perforation, most of which are associated with mechanical trauma to the mucosa or tension in the tissue flaps covering the implants. Bone debris produced during the osteotomy could act as an additional predisposing factor; these are sequestrated and accompanied by chronic inflammatory cell infiltration as well as epithelial-covering reaction. Since this study focused only on specimens from intact mucosa, until further investigation of this phenomenon in spontaneously perforated sites is conducted, no conclusions on the role of these histopathological findings can be made.

Biopsy↗
PubMed2000

Spontaneous early exposure of submerged implants: III. Histopathology of perforated mucosa covering submerged implants.

BACKGROUND: Spontaneous early exposure of dental implants could interfere with the early healing phase of dental implants. These exposures have been clinically classified according to degree of implant exposure from 0 (intact mucosa) to IV (complete exposure). The characteristics of perforated mucosa (Class I and II) covering submerged dental implants were examined histologically in this study. METHODS: Biopsy specimens of 34 Class I and II perforated mucosa covering submerged dental implants were examined histologically. Serial sections were evaluated from the periphery of the specimen to the center of each perforation lesion. RESULTS: Class I specimens presented hyperplastic epithelium characterized by hyperparakeratosis and acanthosis. Chronic inflammatory cells diffusely infiltrated the connective tissue. Sections closer to the perforation revealed gradual epithelial invagination; in the deepest aspect, there was a cyst-like structure in all Class I specimens examined. A thin layer of connective tissue containing necrotic material and debris formed the "cystic" wall proximal to the implant cover screw. Class II specimens presented the same epithelial patterns; however, the cystic structures were replaced by direct contact between the cover screw and the oral cavity via the perforation. CONCLUSIONS: Spontaneous early perforations are the sequela of either traumatic irritation or failure of the tissue flaps to produce primary healing. Most Class I perforations include epithelial invagination and the formation of a cyst-like structure. Necrosis of the base of the "cyst" or enlargement of the perforation results in direct communication between the oral cavity and the covering screw surface (Class II).

Biopsy↗
PubMed1999

Comparative study of splenic wound healing in young and adult rats.

BACKGROUND: Nonoperative management (NOM) of splenic injuries is a common practice in stable trauma patients. Nevertheless, age-related differences in the success rate of NOM have prompted inclusion of age among the criteria of patient selection. Elucidation of the cellular mechanism of splenic wound healing in the young versus that of adults may explain why age can be related to the success of NOM in splenic injuries. METHODS: A laceration was made in the splenic antihilar surface of 40 young and 40 adult male rats. Postoperatively, at specified intervals extending until day 21, spleens were removed, fixed, and examined by routine histopathology. In addition, sections were stained histochemically for collagen fibers and immunohistochemically for myofibroblast histomorphometry. RESULTS: The intense local hemorrhage was resorbed within 48 hours in the young rats, and within 7 days in the adults. Disappearance of germinal centers and other splenic alterations started on the first day in both groups, but regeneration of splenic parenchyma was accomplished after 14 days in the young, whereas in the adults, on day 21 it was still incomplete. Maximal myofibroblast accumulation at the laceration site was seen after two days in the young, whereas in adults only on day 4 (p < 0.0001). Collagen scars were not present in either group. Thickening of the damaged capsule, composed of collagen fibers with yellowish-green polarization colors, was observed only in adult rats. CONCLUSION: Splenic wounds heal by regeneration and not by collagen scarring. In the young, myofibroblasts accumulate in the site of injury faster than in adults. These cells may enhance contraction and increase the rate of wound healing until parenchymatic regeneration is completed. Our results may indirectly explain the higher success rate of NOM of splenic injury in young patients.

Aging↗
PubMed1999

Collagen fibres in the wall of odontogenic keratocysts: a study with picrosirius red and polarizing microscopy.

The collagen in the walls of 15 keratocysts was studied histochemically by staining sections with picrosirius red and examining them with polarizing microscopy. This was compared to 15 cases of dentigerous cyst and 15 cases of radicular cyst. Polarization colours of the collagen fibres were recorded according to their width. No differences were found between the polarization colours of thin fibres (<0.8 microm) in all three lesions; the polarization colours of thick fibres (1.6-2.4 microm) in keratocysts were significantly more greenish-yellow when compared with those of dentigerous cysts and radicular cysts. The staining of the collagen fibres in the keratocysts is similar to that reported in odontogenic neoplasms, which suggests that the stroma of keratocysts could be regarded not just as a structural support of the cyst wall, but as playing a part in the neoplastic behaviour of the cyst.

Analysis of Variance↗
PubMed1998

Bursting pressure in anastomotic healing in experimentally induced colitis in rats.

BACKGROUND: Experimental studies on healing of colonic anastomosis have been thoroughly investigated. However, clinical parameters of the healing process of anastomosis in the inflamed colon has not yet been reported. METHODS: In the present study, healing of anastomosis in trinitrobenzene-sulfonic acid-induced colitis in rats was assessed by measuring the bursting pressure and bursting wall tension. RESULTS: On postoperative day 4, bursting pressure and bursting wall tension were significantly lower (P < 0.001) in rats with colitis with or without anastomosis and normal colon with anastomosis, compared with normal colon without anastomosis. On postoperative day 7, bursting pressure and bursting wall tension of normal colon with anastomosis approached that of normal colon without anastomosis. However, bursting pressure and bursting wall tension of rats with colitis with or without anastomosis remained significantly lower (P < 0.001) than the latter. Furthermore, unlike rats without colitis in which perforation occurred mostly at the anastomotic line, the bursting site in colitic rats was predominantly away from the anastomotic line. CONCLUSIONS: These results suggest that in surgery for inflammatory bowel disease, it is the adjoining inflamed bowel wall that is vulnerable to be perforated in response to increasing intraluminal pressure rather than the anastomosis that is braced by the sutures.

Animals↗
PubMed1998

An immunohistochemical study of p53 and PCNA in inflammatory papillary hyperplasia of the palate: a dilemma of interpretation.

OBJECTIVE: Inflammatory papillary hyperplasia of the palate (IPHP) or the granular type of denture stomatitis, is a non-neoplastic lesion characterized histologically by a significant epithelial hyperplasia and inflammatory infiltrate usually caused by trauma and Candida infection. p53 and proliferative cell nuclear antigen (PCNA) are cell-cycle regulators, that when overexpressed, are considered by many investigators as markers of malignant transformation. The objective of this study was to investigate the immunodetection of p53 and PCNA in IPHP, and to correlate these results with the degree of epithelial hyperplasia and inflammatory infiltrate. MATERIALS AND METHODS: In 12 cases diagnosed clinically as IPHP, Candida was cultured from the denture base and the palatal mucosa. Lesions were biopsied and stained with H&E for histomorphometric analysis of the epithelial width and inflammatory infiltrate. PAS and Gram stains were used for screening of Candida. Sections were immunostained with DO-7 for p53 and PC-10 for PCNA. Fifteen palatal biopsies obtained from autopsies of edentulous subjects with normal palatal mucosa served as controls. RESULTS: All cultures of swabs from both the palatal mucosa and denture base were positive for Candida. Candidal hyphae could not be identified in PAS stained sections. Small foci of Gram-positive organisms were found in two cases of IPHP. Epithelial width and inflammation were significantly higher in IPHP than in controls (P < 0.001). A three-fold increase in positively stained cells for p53 and a two-fold increase in positively stained cells for PCNA were seen in IPHP compared with controls (P < 0.001). CONCLUSIONS: Although a significant increase in the immunodetection of p53 and PCNA may indicate a malignant potential, IPHP has never been reported to undergo malignant transformation nor is it associated with cytologic signs of dysplasia. The increase in the epithelial width and inflammation degree is probably associated with the colonization of the denture bases with Candida organisms. The increased detection of p53 and PCNA can be a secondary effect of cytokines originating from both the inflammatory cells and the keratinocytes. Thus, immunodetection of p53 and PCNA by current immunohistochemical methods on archival tissues is neither specific nor sensitive enough to be used as indicators for malignant potential in the absence of cytological dysplastic changes or genetic proof of mutated cell cycle genes.

Aged↗
PubMed1998

Castration prevents calcium channel blocker-induced gingival hyperplasia in beagle dogs.

1. The purpose of this study was to investigate testosterone's role on the calcium channel antagonist oxodipine-inducing gingival hyperplasia in a dog model. 2. Two experiments were conducted using castrated and intact male dogs. Oxodipine was administered orally for 90 days, at a dose of 24 mg/kg/day. In the first experiment, the occurrence of gingival hyperplasia was evaluated. In the second, the gingival index (GI) and gingival hyperplasia index (GHI) were recorded and correlated with serum levels of testosterone. 3. A significant positive correlation between GI, GHI and plasma testosterone was noted. Castrated dogs were injected with testosterone, 4 months after the start of oxodipine treatment, while in the non-castrated dogs, administration of oxodipine was stopped. Castration correlated with lack of GH, while testosterone injection to the same dogs was associated with an increase of GI and GHI. 4. Since it is known that testosterone receptors are present in the gingiva, it is proposed that oxodipine-induced gingival hyperplasia could be mediated by the calcium channel blocker on plasma testosterone levels.

Animals↗
PubMed1997

The source of NMR-detected motional anisotropy of water in blood vessel walls.

2H Double quantum-filtered (DQF) NMR spectroscopy of deuterated water is sensitive to the presence of order in biological systems. This is because the only nuclei that are detected are those with residual quadrupolar interactions due to their anisotropic motion. In the present study, samples of aorta, coronary and carotid arteries, and vena cava were studied in parallel by 2H DQF NMR and by light microscopy. The average quadrupolar splitting, calculated from the NMR data, varies considerably among the different blood vessels, with high reproducibility for each type of vessel. Polarization microscopy examinations using collagen-specific staining with picrosirius red, have shown a variety of color profiles for the different blood vessels. These reflect different physical modes of aggregation (packing and thickness) of collagen fibers. A correlation was found between the NMR parameters and the color profiles of the picrosirius red-stained sections. Treating the blood vessels with 90% formic acid resulted in the elimination of the 2H DQF NMR signal. Histological analysis demonstrated a complete degradation of collagen and muscle, whereas the elastin filaments were preserved. Evidence is given that the 2H DQF NMR signal is dominated by the contribution of water molecules interacting with the collagen fibers.

Animals↗
PubMed1997

Experimental tongue cancer in desalivated rats.

A group of 39 rats underwent excision of the submandibular and sublingual glands and ligation of the parotid ducts through the midventral incision of the neck, while the control group (41 rats) underwent a sham operation. All rats were administered 4NQO in a final concentration of 0.001% in drinking water. At 7, 14, 22 and 28 weeks after administering 4NQO, both groups of rats were killed and their tongues dissected, inspected and then fixed in 10% buffered formalin for histopathological examination. Clinical examination during the first 14 weeks revealed that rats in both groups looked healthy and no differences in body weight were noticed. Afterwards, the average weight gain of the desalivated rats was lower than in the control group (P < 0.01). The number of macroscopic oral lesions increased with time in both groups. However, in the desalivated rats, the first identifiable lesions were seen as early as week 7, whereas in the control group macroscopic lesions were seen only after 22 weeks. Histological examination revealed more affected rats in the desalivated group in the first 14 weeks after administering the carcinogen; lesions showed more severe pathological changes including two cases with evidence of squamous cell carcinoma. The differences between the desalivated groups and control decreased after 22 weeks with almost no differences at the end of the experiment.

4-Nitroquinoline-1-oxide↗
PubMed1996

Histomorphometric evaluation of experimentally induced colitis with trinitrobenzene-sulphonic acid in rats.

Colitis was induced with trinitrobenzene-sulphonic acid (TNB) in rats and a histomorphometric study was performed as a possible scoring system for disease activity. The affected colon was examined 10, 20, 40 and 60 days after TNB administration. Quantitative microscopic analysis was performed on the following histologic parameters: necrosis, mucosal epithelium, muscularis fibres, inflammation, granulation tissue and fibrosis. Clinically, the rats were sick, especially on days 10 and 20 after TNB injection. Concomitantly, a peak necrosis score involving the full thickness of the colonic wall was recorded on day 10. The inflammatory reaction was most intense 20 days after TNB injection. After 60 days, marked epithelial regeneration was seen and most of the inflammatory reaction had subsided. A good correlation was found between clinical features and quantitative histomorphometric characteristics of colitis. The criteria described allow a precise description and quantification of the inflammatory and healing process of TNB-induced colitis in rats.

Acute Disease↗
PubMed1996

The central odontogenic fibroma and the hyperplastic dental follicle: study with Picrosirius red and polarizing microscopy.

The central odontogenic fibroma (COF) is an uncommon odontogenic tumor in which the microscopic appearance is similar to that of the hyperplastic dental follicle (HDF). Distinction between these lesions is based mainly on their clinical and radiologic features. The collagen of 5 cases of COF and 13 cases of HDF was studied histochemically by staining sections with Picrosirius red and examining them by polarizing microscopy. Polarization colors of the collagen fibers of the lesions were recorded according to their width. While no differences were seen between the polarization colors of thin fibers (<0.8 mm) in both lesions, the polarization colors of thick fibers (1.6-2 mm) of COF were significantly more green and greenish-yellow as compared with those of HDF. These findings suggest that the Picrosirius red polarization method can be used as a diagnostic tool to differentiate between COF and HDF..

Azo Compounds↗
PubMed1996

Lectin histochemistry of the submandibular and sublingual salivary glands in rats.

Tissue sections from rat submandibular and sublingual glands were studied with lectin probes to identify terminal sugars of the glycoconjugates in various cell types of the salivary glands. The lectins used in the study were Canavalia ensiformis (Con A), Triticum vulgaris (WGA), Succinyl WGA (S-WGA) Ricinus communis I (RCA-I), Arachis hypogaea (PNA), and Ulex europeaus (UEA-I). The cytoplasm and cell membrane of both the serous and mucous acinar cells present high similarity in the distribution of some sugar residues, but differ considerably in the expression of specific sugars which appear either in the serous or in the mucous cells. The cytoplasm and cell membrane of the serous and mucous acinar cells express Mannose (Man) and Glucose (Glc), but lack Galactose (Gal), and N-acetylgalactosamine (GalNAc). Fucose (Fuc) is present only in the mucous acinar cytoplasm. The moderate to intense binding of WGA to the acinar and ductal cells and the lack of binding of S-WGA, indicate the presence of sialic acid rather than N-acetylglucosamine (GlcNAc). These sialic acid residues are not associated with PNA-binding sugar sequences as pretreatment with neuraminidase is not associated with exposure of additional PNA receptors.

Acetylglucosamine↗
PubMed1995

Intestinal anastomosis healing in rat: collagen concentration and histochemical characterization by Picrosirius red staining and polarizing microscopy.

The study was designed to characterize collagen fibers in the healing intestinal anastomosis of rat by examining collagen concentration and recording the polarization colors of the collagen fibers in Picrosirius red-stained tissue sections. No significant changes in collagen concentration expressed by hydroxyproline content were noted at the anastomotic site at various postoperative time points. In the normal intestine, the predominant polarization colors were in the yellow to yellow-orange range, signifying tightly packed, matured collagen. During the first postoperative week, collagen fibers at the anastomotic region exhibited mainly polarization colors in the green to green-yellow range, implying less packed intermediate collagen fibers. After 2 weeks, collagen fibers at the anastomotic region gradually reacquired their preoperative polarizing texture. These findings strongly suggest that the "quality" rather than the quantity of collagen fibers plays an important role in maintaining the tensile strength of the healing intestinal anastomosis.

Anastomosis, Surgical↗
PubMed1995

In vitro effect of ciprofloxacin on HT-29 human colon carcinoma cell line: assessment of cell proliferation by thymidine uptake and silver nucleolar organizer regions (AgNOR) histomorphometry.

In an in vitro study, the effect of ciprofloxacin was examined on proliferation of HT-29 human colon carcinoma cell line. Cell proliferation was measured by 3H-thymidine uptake and silver nucleolar organizer region (AgNOR) histomorphometry. A significant increase in [3H]thymidine incorporation (p < 0.05) parallel with a significant increase in the mean AgNOR clusters/cells (p < 0.01) was noted after 5 days of cell exposure to ciprofloxacin. It is suggested that the assessment of AgNOR variables is useful in examination of quinolone effect on HT-29 human colon carcinoma cell proliferation.

Carcinoma↗