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Biomedical subjects

S Ruacan

Publications and source records attributed to S Ruacan.

At least 19 recordsLinked to original sources
PubMed2002

Research ethics and scientific misconduct in biomedical research.

Scientists have the responsibility of judging what is best for the patient and the optimal conditions for the conduct of the study. All physicians should ensure that research they participate in is ethically conducted. Every clinician should learn and receive training in the responsible conduct of research and publication, and each project must be reviewed by an institutional review committee. Scientific misconduct is defined as any practice that deviates from those accepted by the scientific community and ultimately damages the integrity of the research process. "Sloppy Research" and "Scientific Fraud" include activities which can violate science, records and publication. Sloppy research is due to absence of appropriate training in research discipline and methodologies. In contrast, scientific fraud is defined as deliberate action during application, performance of research, and publication. It includes piracy, plagiarism and fraud. Research institutions should adopt rules and regulations to respond to allegations, start investigational operations and perform appropriate sanctions.

Clinical Trials as Topic↗
PubMed2002

Detection of inflammatory lymph nodes in rabbits by 99mTc-HIG lymphoscintigraphy.

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and evaluation of inflammatory lymph nodes.

Animals↗
PubMed2002

Experimental trigeminal glycerol injection in dogs: histopathological evaluation by light and electron microscopy.

We investigated the effects of percutaneous gasserian glycerol injection in dogs and reviewed the histopathological changes. Experiments were performed in 16 adult healthy mongrel dogs. In group 1 (8 dogs) normal saline and in group 2 (8 dogs) pure glycerol was injected in the right trigeminal ganglion. After these procedures, dogs in each group were sacrificed after 24 h (3 dogs), 7 days (3 dogs), 21 days (2 dogs). The trigeminal ganglion and nerve of both sides were removed by using microsurgical techniques and examined by light and electron microscopy. Group 1: in all sections, nerve cells, myelinated and nonmyelinated fibers revealed normal patterns with slight fibrosis. Group 2: in all sections, myelinated fibers showed disintegration and swelling of the myelin sheath, rupture of axon continuity, destruction of basal lamina, deformation of the myelin-axon relationship by both light microscopy and electron microscopy. The sections examined by electron microscopy also showed axonolysis in nonmyelinated fibers. The changes after 7 and 21 days were less prominent than after 24 h. In the left sides, there are no pathological changes. Glycerol has a neurolytic effect on the dog's trigeminal ganglion. These effects were not specific and selective for myelinated and nonmyelinated nerve fibers.

Animals↗
PubMed2002

Poly(D, L-lactide/epsilon-caprolactone)/hydroxyapatite composites as bone filler: an in vivo study in rats.

In this study, a novel composite bone substitute was implanted in animal models (rats) and their in vivo characteristics were examined. A D,L-lactide and E-caprolactone copolymer (Mw: 80,000; Mn:40,000, and PI:2.00) was synthesized by ring-opening polymerization of the respective dimers using stannous octoate as the catalyst. The final ratio of D,L-lactide to epsilon-caprolactone obtained by 1NMR was 60/40. Hydroxyapatite (HA) powder was loaded in the copolymer. The HA/copolymer ratio was 60/40 (w/w). These composites were easily shaped by hand. Animal tests were performed on mature wistar rats (n=30). Defects were created on the proximal, the thickest part of the femur. The bone defects of the first group were filled with polymer/HA composite, the second group filled with only HA and the third group was left empty. Histologic examination of bone tissues showed new bone formation around the yellow-green polymer/HA composite material in the first group of animals whereas no evidence of new bone growth was observed in other groups.

Animals↗
PubMed2001

Fibrocartilaginous mesenchymoma of the distal femur: case report and literature review.

A case of a 9-year-old boy with fibrocartilaginous mesenchymoma located in the distal femur is presented. Fibrocartilaginous mesenchymoma is a rare tumor. There have been 17 cases reported since 1984. The presenting complaint was pain and local discomfort. Radiological examination showed lytic and sclerotic lesions located in the distal femur. Magnetic resonance imaging showed that there was no soft tissue expansion. Differential diagnosis included fibrocartilaginous dysplasia, dedifferentiated chondrosarcoma, desmoplastic fibroma, fibrosarcoma and low-grade osteosarcoma. The diagnosis of the tumor in a state hospital would not have been possible. Wide resection of the tumor and resection arthrodesis with an intramedullary nail has yielded good results. The patient has been disease free for 4 years. Pathological diagnosis of this very rare tumor may be challenging; the treatment should be wide resection of the tumor.

Adolescent↗
PubMed2001

Hypereosinophilia and metastatic anaplastic carcinoma of unknown primary.

The differential diagnosis of eosinophilia may sometimes be difficult. Eosinophilia may occur in a diverse array of conditions from parasitic infestations to malignacies. Idiopathic hypereosinophilic syndrome has also been described. A 65-year-old male patient presenting with eosinophilia of obscure etiology is described in the present report. Three years after the diagnosis of eosinophilia, metastatic anaplastic carcinoma of unknown primary was detected. Differential diagnosis is disscussed briefly. It is stressed that patients with hypereosinophilia of unknown etiology must be screened for malignancy regularly during follow up.

Abdominal Neoplasms↗
PubMed2001

Epidermolysis bullosa acquisita: clinical manifestations, microscopic findings, and surgical periodontal therapy. A case report.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is an uncommon, acquired, chronic subepidermal bullous disease. This report describes a case of EBA with gingival involvement. A 43-year-old woman with EBA was referred to our clinic for periodontal therapy because of gingival tenderness and bleeding. She has been on cyclosporin A therapy for the last 2 years. METHODS: Clinical findings were analyzed. Anterior gingivectomy operations were performed in 2 stages. The samples obtained during the surgery were examined using histopathologic, immunohistologic, and electronmicroscopic methods. Long-term effects of the surgical periodontal treatment on gingiva were evaluated both clinically and microscopically. RESULTS: The dentition displayed minimal enamel hypoplasia. Decayed, missing, and filled surfaces score was found to be elevated. Periodontal examination showed generalized diffuse gingival inflammation and gingival enlargement localized mainly to the anterior region. Nikolsky's sign was positive. However, wound healing was uneventful after the operations. Microscopic findings were similar to those obtained from the skin. Twenty-one months after the operations, Nikolsky's sign was negative and no remarkable gingival inflammation was noted. Microscopic examination revealed that the blisters were fewer in number and smaller in size. CONCLUSIONS: These results indicate that gingival tissues may also be involved in EBA. Uneventful wound healing after periodontal surgery in this case suggests that periodontal surgery can be performed in patients with EBA. Moreover, both our clinical and histopathologic findings imply that gingivectomy proves useful in maintaining gingival integrity in these patients. Our data may also suggest that the patients with EBA are highly likely to develop dental caries.

Adult↗
PubMed2001

An adenomatoid odontogenic tumor with unusual clinical features.

Adenomatoid odontogenic tumors are uncommon odontogenic lesions characterized by duct-like structures that form from the epithelial component of the lesion. Most of these masses develop in the second or third decade of life, and there is a strong female bias in occurrence. Typically, these lesions arise in the lateral incisor/canine region of the maxilla, where they produce a swelling. Only in very rare cases is the lesion found distal to the premolar area. Nearly all of these growths are associated with an embedded anterior maxillary tooth (usually a canine), and most resemble a 1-3 cm diameter dentigerous cyst. Radiopacity is reported in two-thirds of cases. This article describes the case of a 9-year-old Caucasian male who presented with a painless swelling in the left premolar-molar region of his maxilla. This case is of particular interest because the features (patient age, gender, lesion location, size, and radiographic findings) were not typical of adenomatoid odontogenic tumor.

Bicuspid↗
PubMed2001

Myasthenia gravis and lymphoblastic lymphoma involving the thymus: a rare association.

Myasthenia gravis (MG) is an autoimmune neuromuscular junction disease. An association between thymic epithelial neoplasms and MG is well known. However, it is rarely associated with hematologic malignancies. In particular, very few cases of lymphoblastic lymphoma involving the thymus and MG have been reported. Here we report a case T-cell lymphoblastic lymphoma involving the thymus who developed MG after the initial diagnosis. The patient initially presented with a mediastinal mass which was diagnosed as lymphoblastic lymphoma. MG was diagnosed during leukemic relapse in this patient and was based on clinical presentation and neurophysiologic studies including single fiber electromyography (EMG) and repetitive nerve stimulation tests. In contrast to the other cases with such an association, the myasthenic symptoms presented nine months after the diagnosis of lymphoma by thymectomy. The patient had a highly aggressive clinical course and was resistant to various chemotherapy regimens.

Adult↗
PubMed2000

Ossifying fasciitis.

A case of ossifying fasciitis occurring in the left femoral region of a 57-year-old male is reported. The patient complained of pain in his left lower extremity which was the site of previous catheterization. During a left femoropopliteal by-pass, a firm and cylindric mass measuring 5 x 3 x 2.5 cm in size was found and extracted from the left groin. Histologically, a reactional lymph node and an irregularly shaped lesion extended into the perinodal fat tissue which is composed of proliferating fibroblasts with occasional mitotic activity. Within this fibroblastic proliferation, immature woven bone composed of osteoid with calcification and chondroid differentiation were seen. Metaplastic bone is an uncommon finding in cases of nodular fasciitis, parosteal fasciitis, cranial fasciitis and florid reactive periostitis. Ossifying fasciitis is known as an uncommon variant of nodular fasciitis. It is an uncommon post-traumatic benign lesion of subcutaneous tissue with an unclear etiology of ossification which is neither related with a bony structure nor contains any muscle tissue. This lesion has been reported only once previously, in the femoral region after a trauma history of catheterization.

Fasciitis↗
PubMed2000

Primary breast lymphomas--a retrospective analysis of twelve cases.

This study was undertaken to define the natural history and treatment results of patients with primary breast non-Hodgkin's lymphoma (NHL). Twelve female patients who had been followed at Hacettepe University Hospital between 1973 and 1997 were retrospectively evaluated. All patients presented with breast masses (6 in the right breast and 6 in the left) that had recently enlarged. The most common histologic subtype was diffuse, small cleaved-cell lymphoma. Chemotherapy regimens were employed in 9 patients. Radiotherapy was delivered to the breast and its lymphatics in 8 patients. Lumpectomy, simple or modified radical mastectomy was performed in 5 cases. An objective response was attained with surgery, chemotherapy, or radiotherapy alone in 2, 1, and 1 cases, respectively. Combined modality treatment including either two or three modalities was successful in 7 cases. The median progression-free and overall survival times were 49 and 56 months, respectively. Although primary NHL of the breast is a rare disease compared to carcinoma, it should be considered in the differential diagnosis of breast masses.

Adolescent↗
PubMed2000

Primary pleural lymphoma: an unusual presentation of childhood non-Hodgkin lymphoma.

A case of primary pleural non-Hodgkin lymphoma in a 2.5-year-old girl is reported. The patient had pleural involvement as the initial and only manifestation of the disease. Histopathologic examination showed lymphoblastic lymphoma of T-cell origin. The child received the modified LSA2-L2 protocol. During the maintenance treatment, she had an isolated central nervous system relapse and died of neutropenic sepsis. To the authors' knowledge this represents the first case report of primary pleural lymphoma in the childhood period.

Child, Preschool↗
PubMed2000

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) associated with prostatic carcinoma.

Inappropriate antidiuretic hormone secretion (SIADH) may occur in a variety of diseases, including malignancies, and can be induced by drugs. We report a case of SIADH associated with prostatic carcinoma. A 50-year-old man was admitted to hospital with severe flank pain and weight loss. The diagnosis of SIADH syndrome and prostatic carcinoma was established, and hormonal therapy was instituted. However, the patient died in a month without any response to therapy. We conclude that prostatic carcinoma may cause SIADH and should therefore be considered in the differential diagnosis.

Abdominal Pain↗
PubMed2000

Correlation of flow cytometric parameters and transferrin receptors with gallium-67 scintigraphic images in lymphoma patients.

The purpose of this study was to determine the correlation of flow cytometric parameters and transferrin receptors with gallium-67 scintigraphic imaging results in Hodgkin's and non-Hodgkin's lymphoma patients. DNA content and cell cycle analyses were performed using flow cytometry and transferrin receptor analysis was carried out by the immunohistochemistry technique in 24 patients aged between 16 and 62 years. All patients underwent gallium-67 scintigraphy, and tumour to background ratios were calculated. The findings were correlated with computed tomography and/or magnetic resonance imaging. A strong relationship was observed between flow cytometry and transferrin receptor expression with gallium-67 tumour scintigraphy [P = 0.005, r = 0.054 and P = 0.038, r = 0.54 (Spearman test), respectively]. The results of this study show that there is a close correlation between each of these modalities and, as they reflect the biological activity of the tumour, together they have a major role in treatment and follow-up.

Adolescent↗
PubMed2000

The effect of age on proliferating cell nuclear antigen expression in oral gingival epithelium of healthy and inflamed human gingiva.

BACKGROUND: Age-related changes in proliferative activity in human gingival epithelium are uncertain. Proliferating cell nuclear antigen (PCNA) is a nuclear protein associated with the cell cycle. Nuclear PCNA immunoreactivity is found in the proliferative compartment of normal tissues. The aims of this study were to investigate the localization of PCNA expression in oral gingival epithelium (OGE) and to define the age-related changes as to PCNA-proliferative index (PI) in inflamed as well as healthy gingiva. Mitotic index (MI) was also used as a conventional marker of cell proliferation. Additionally, the effect of aging upon the maximum epithelial thickness (MET) was determined. METHODS: Twenty older (65 to 85 years) (study) and 20 middle-aged (35 to 45 years) (controls) subjects were included in the study. Biopsies were obtained both from healthy and inflamed gingiva. The expression of PCNA was evaluated in formalin-fixed, paraffin-embedded gingival samples using an immunoperoxidase technique and PC 10 monoclonal antibody to PCNA. Hematoxylin and eosin stained sections were used for the quantitative measurement of MI and MET. RESULTS: All the tissue sections contained positive staining cells for PCNA in the gingival epithelium. Although PCNA expression was observed both in the basal and suprabasal layers, it was more prominent in the suprabasal layers. PI in inflamed gingiva was significantly higher in the older group. However, no significant difference was observed between the study and control groups with respect to PI in healthy gingiva. When all the subjects taken into the study were analyzed as a single group, PI in the inflamed gingival samples were found to be increased with aging. Nevertheless, no age-related change was noted in MI and MET. In both the study and the control groups, PI, MI, and MET were found to be increased due to inflammation. CONCLUSIONS: Our data indicate that PCNA expression in inflamed gingiva is higher in older subjects. Furthermore, a significant correlation was noted between aging and PCNA expression in inflamed gingiva. As there is no increase in mucosal epithelial thickness despite increased proliferation, we speculate that the duration of the PCNA+ phase in cell cycle may be longer in older subjects. This study also implies that PCNA immunolocalization can be used as an index of the state of cell proliferation in both biological and pathological events of the gingiva and/or other mucosal tissues.

Adult↗