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Biomedical subjects

H Noma

Publications and source records attributed to H Noma.

At least 55 records · Page 3Linked to original sources
PubMed1998

Microvascular anastomosis in oral and maxillofacial surgery: a comparative study of recipient artery between Japanese and German patients.

The causes of unsuccessful microsurgery include pre-existing histopathological changes in the recipient vascular wall. Medical history, preoperative therapy, and life background such as aging may have complex effects on the morbid state of recipient vessels. Focusing on these points, specimens of recipient vessels were obtained at the microsurgery of the oral and maxillofacial regions, and the condition of the arterial wall was analyzed pathologically. This study was performed in both Japan and Germany simultaneously, and the results are compared between the two countries. A higher percentage and a more advanced abnormality of the artery seem to exist in the German patients than in the Japanese patients. This difference could be due to the severe preoperative multimodal chemo- and radio-therapy more often applied in Germany and the higher incidences of systemic diseases such as hypertension and diabetes as well as of smoking in German population. The success rate of the surgery is, however, the same in both countries. It could be concluded that the viability of the flaps was not affected directly by preoperative damage to the recipient artery.

Adult↗
PubMed1998

A clinical analysis of the recovery from sensory disturbance after sagittal splitting ramus osteotomy using a Semmes-Weinstein pressure aesthesiometer.

A number of studies of evaluation methods for sensory disturbance after sagittal splitting ramus osteotomy (SSRO) are known. To compare postoperative sensory disturbances among patients in different hospitals, a highly reproducible and standardized sensory test is required. In the present study, we measured the tactile threshold in the region innervated by the mental nerves in 45 patients (90 sides) after SSRO using a Semmes-Weinstein pressure aesthesiometer. The percentage of recovery to the normal level defined by Bell was 72.2% at one week, 82.2% at 4 weeks, and 90.0% at 8 weeks after SSRO. The recovery process was evaluated by classifying the postoperative sensory disturbance into 5 grade levels according to Bell's interpretation scale. The results showed that the SW sensory test is useful for evaluation of the recovery process from sensory disturbance after SSRO. Some improvements of this test were also discussed.

Adult↗
PubMed1998

Central island tongue flap.

Pedicled tongue flaps have proved to be an effective method of repairing defects due to tissue loss in the oral cavity. Their central position, mobility, and excellent blood supply make their use feasible in a variety of sites. This paper describes the use and applications of central island tongue flaps to reconstruct defects of anterior floor of the mouth. This procedure was conducted at the Department of Oral and Maxillofacial Surgery, Medical University Hanover, introducing an improved surgical method and presenting the actual operation performed in our department. This method is considered superior for resurfacing the anterior floor of mouth defects because it is easy to perform and results in recovery of function and cosmetics.

Carcinoma, Squamous Cell↗
PubMed1997

Repair of a cheek defect with the tissue expander method: a case report.

A 28-year-old female had a severe depressed deformity of the left cheek due to false local injection of ZnCl2 into her buccal mucosa instead of an anesthetic. After several attempts at plastic surgery in another hospital with unsatisfactory results, she was treated surgically in our clinic using cheek skin expanded by a tissue expander. The outcome was satisfactory.

Adult↗
PubMed1996

Histological changes in vessels used for microvascular reconstruction in the head and neck.

Recipient vessels from the head and neck region were histologically examined in 30 patients who had undergone extensive tumor resection necessitating microvascular tissue reconstruction. Past illnesses considered to be risk factors included hypertension, myocardial disease, lung disease, cirrhosis, diabetes, nephritis, as well as extensive nicotine and alcohol abuse. Blood vessels chosen for microsurgical anastomosis were exclusively examined histologically in this study. Patients undergoing microvascular surgery demonstrated vessel abnormalities in 93%. The frequency of dysplasia was higher in the arteries than in the veins (73% and 26%, respectively). Marked thickening of the blood vessel wall and severe exfoliation of the endothelial cells were observed in most arteries. Fibrodysplasia and exfoliated endothelial cells were more frequently observed in the recipient arteries than the graft arteries. Only slight thickening of the vessel wall and mild fibrodysplasia were seen in the veins. Two graft failures were correlated to technical errors rather than pre-existing vessel lesions. This study revealed that most patients undergoing microsurgery in the head and neck region demonstrate pre-existing damage in vessels, which generally hinders anastomosis. Although the study tried to identify fully the interrelationships between the extent of dysplasia, past medical history, preoperative therapy, risk factors and factors that cause free-graft failure, pre-existing changes in the recipient and graft vessels may cause technical difficulties and must be regarded as additional factors contributing to graft failure.

Adolescent↗
PubMed1996

Clear cell odontogenic carcinoma in the mandible: histochemical and immunohistochemical observations with a review of the literature.

A rare case of clear cell odontogenic carcinoma was investigated using histochemical and immunohistochemical methods. The tumor occurred in the anterior mandible of a 69-year-old Japanese man. Histologically, the tumor was composed mostly of large clear cells and squamous cells. Columnar-shaped cells with basophilic nuclei polarized away from the basement membrane were observed at the periphery of the tumor foci. The tumor cells had aggressively invaded muscle and perineural tissues. The tumor cells were positive for PAS staining. Immunohistochemically, tumor cells reacted positively to keratin, cytokeratin19, epithelial membrane antigen, and S-100 protein. The tumor was diagnosed as a clear cell odontogenic carcinoma. Its characteristics are discussed in term of its histopathological, histochemical and immunohistochemical features.

Aged↗
PubMed1996

Use of the buccal fat pad as a pedicle graft.

A technique was developed to use the pedicle buccal fat pad as method for closing an oro-antral communication. The buccal fat pad is situated in the posterior part of the maxilla and bounded by the pterygopalatine fossa, buccal muscle, and masseter muscle. It is supplied by blood from small branches of the maxillary artery, the superficial temporal artery, and the facial artery. Generally, the buccal fat pad can be easily reached by a horizontal incision over the periosteum near the maxillary third molar. As much as 60 x 50mm2 can be obtained. For reconstructive surgery, the buccal fat pad is suitable for closing the sinus near the hard and soft palate and naso-oral fistulae. In our case, graft tissues after surgery healed satisfactorily, began to epithelialize at two weeks after operation, and appeared with normal mucous-like changes at about one month. Thus, the pedicle buccal fat pad is a safe, simple, convenient, and effective grafting method, if it is applied to appropriate cases.

Adipose Tissue↗
PubMed1996

Long-term stability following surgical orthodontic treatment of mandibular prognathisms: investigation by means of lateral X-ray cephalogram.

The purpose of this study was to investigate the long-term stability of jaw relations and occlusion following surgical orthodontic treatment of mandibular prognathisms and skeletal openbites. Subjects consisted of fifteen adult patients. Ten patients underwent the sagittal split ramus osteotomy (SSRO) of the mandible and five patients underwent two jaw surgery (Le Fort I osteotomy of the maxilla and SSRO of the mandible). They were observed over five years after the end of active treatment, and lateral X-ray cephalograms were taken at each stage. In the SSRO group, pogonion was retrograded an average of 8.7mm due to the operation and it was further replaced 0.4mm backward after the end of active treatment. Although the vertical distance between nasion and menton decreased 2.9mm between the operative period, it increased 1.8mm after the end of active treatment. On the other hand, in the two jaw surgery group, point A was advanced 4.0mm forward and < SNA increased 3.1 degrees between the operative period. Pogonion was retrograded 11.4mm between the same period, but moved 0.7mm forward after the end of active treatment. A comparison of the osteosynthesis methods revealed that pogonion in the wiring group was retrograded 8.3mm backward between the operative period, but moved 2.1mm forward during the postsurgical orthodontic treatment. Pogonion in the rigid group was retrograded 12.6mm backward between the operative period, but moved 1.6mm forward during the postsurgical orthodontic treatment. However, both groups were stabilized completely after the end of active treatment. A comparison of the differences in the orthodontic treatment method revealed that < Ul-SN in the extraction group inclined 8.3 degrees lingually during presurgical orthodontic treatment, but it tipped 7.0 degrees labially during the postsurgical orthodontic treatment and inclined 3.4 degrees lingually after the end of active treatment. < Ul-SN in the non-extraction group inclined 5.5 degrees lingually during the presurgical orthodontic treatment, but it tipped 2.0 degrees labially during the postsurgical orthodontic treatment and inclined 1.9 degrees lingually after the end of active treatment.

Adult↗
PubMed1996

Transposition of the mental nerve and inferior alveolar nerve trunk.

Transposition of the mental nerve trunk is performed as a preprosthetic procedure. It is effective for patients with hyperesthesia caused by dental prosthesis and resorption of the alveolar ridge caused by aging. It is also performed to protect a location for implant insertion and to preserve the inferior alveolar nerve during mandibular tumor excision surgery. The demand for this surgery is increasing. The disadvantages of the surgery performed with the usual methods include the difficulty of the procedure and the long operation time. In an attempt to solve these problems, this study was conducted at the Department of Oral and Maxillofacial Surgery, Medical University Hanover, introducing an improved surgical method and presenting the actual operation performed in our department. This surgical method is considered superior because it is easy to perform, requires no special equipment and results in recovery of the mental nerve after surgery.

Adult↗
PubMed1996

Establishment and characterization of two human bladder cancer cell lines.

Two cell lines, SNK57 and NKB1, were established from human bladder cancer: SNK57 from a transitional cell carcinoma (TCC) in a 73-year-old female and NKB1 from a residual TCC following MEC (methotrexate, farmorubicin and cisplatin) chemotherapy in a 64-year-old female. Doubling time of SNK57 and NKB1 cells was 24 hours and 45 hours, respectively. The chromosome number of both cell lines was 100 percent anueploid with a mode of 43 chromosomes for SNK57 and 107 for NKK1. Both SNK57 and NKK1 induced tumors at the site of subcutaneous injection of nude mice. Histology of the tumors closely resembled that of the original ones from which they were derived. Although NKB1 was 4 times more resistant to doxorubicin (ADM) as compared to SNK57, overexpression of MDR1 gene product, P-glycoprotein was not evident in NKB1 as well as SNK57. These two new cell lines with different chemosensitivity to ADM may be a useful model for developing new chemotherapeutic strategies for human bladder cancer.

Aged↗
PubMed1996

Establishment of two human renal cell carcinoma cell lines with different chemosensitivity.

Two cell lines, SKR1 and NKK1, were established from renal cell carcinomas (RCC) with different histopathologic characteristics: SKR1 from grade 3, solid type, pleomorphic cell type carcinoma in a 66-year-old male and NKK1 from grade 2, alveolar type, clear cell carcinoma in a 49-year-old female. Electron microscopic study showed the presence of microvilli on cell surface and desmosome-like structures between cells in both lines. Doubling time and plating efficiency of SKR1 were 28 h and 37%, respectively, whereas those of NKK1 were 45 h and 22%, respectively. The chromosome number of both cell lines was 100% aneuploid with a mode of 74 chromosomes for SKR1 and 84 for NKK1. Both SKR1 and NKK1 induced tumors at the site of subcutaneous injection of nude mice. The morphologic characteristics of the tumor were similar to those of each original tumor. NKK1 was about 20 times more resistant to doxorubicin and vinblastine as compared to SKR1. Expression of P-glycoprotein was considered to be one of the factors responsible for such multidrug resistant phenotype of NKK1 cells. These two lines with different chemosensitivity may be a useful model for developing new therapeutic strategies for RCC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

High-resolution and analytical electron microscopic studies of new crystals induced by a bioactive ceramic (diopside).

Diopside has been developed for use in dental root implants and for the filling of bone defects. In previous studies, diopside developed hydroxyapatite (HA) on its surface and achieved a direct bond with bone. The purpose of this study was to investigate the mechanism of crystal formation on the diopside surface. We ultrastructurally evaluated the interface between new diopside-induced crystals and diopside. Specimens were prepared in three experiments: (1) Granular diopside was immersed in simulated body fluid (SBF); (2) granular diopside was implanted into a cavity in rabbit bone; and (3) a diopside dental root implant was implanted into a Japanese monkey. The specimens were examined by contact microradiography, high-resolution transmission electron microscopy, and analytical electron microscopy. In the experiment with SBF, many platelet-like crystals formed in the diopside surface layer. The lattice of diopside and that of the new crystals were very close, but no clear continuation of the lattice was observed. In the experiments which used a rabbit and a monkey, contact microradiography showed close contact between bone and diopside. High-resolution transmission electron microscopy revealed crystal growth from the diopside surface layer, and continuity between the diopside lattice and that of the new crystals. The morphological characteristics of the new crystals and the results of these analyses suggest that these new crystals are HA. With regard to the mechanism by which crystals are formed on the diopside surface layer, it is possible that epitaxial crystal growth could originate as a nucleus on the surface. In this case, epitaxial crystal growth of primarily octacalcium phosphate (OCP) may have occurred, and this may have changed to HA by a phase transition. However, epitaxial growth of OCP on the diopside surface is still highly speculative, since there is no direct supporting evidence.

Animals↗
PubMed1995

Purification and characterization of bone morphogenetic protein derived from bovine bone matrix.

Bone morphogenetic protein (BMP) was extracted from bovine bone matrix and purified. The 6M guanidine-HCL soluble fraction and the final purified substance were bioassayed by implantation of about 3 mg into the thigh muscles of C3H strain mice. These specimens induced new bone in three weeks when implanted into muscle pouches of the C3H mouse. The final fraction purified by liquid chromatography (fraction III) was shown to be homogeneous by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis (SDS-PAGE). The molecular weight of the bovine bone matrix-derived BMP was estimated to be about 14-18 kDa in MW. The main components correspond to a MW of 18 kDa and 14 kDa when they are compared with the mobilities of standard proteins. These were invariably present in fractions with osteoinductive activity.

Animals↗
PubMed1995

An electron microscopic study of the processes of nerve regeneration after lyophilized nerve homografting.

The objective of the present study was to investigate the role of the Schwann cell basal lamina in nerve regeneration. To achieve this goal, we observed the process of axonal regeneration within a lyophilized nerve graft, in which only the basal lamina of the Schwann cell persisted. Sciatic nerves were removed from rats and lyophilized to kill the Schwann cells and other components. These grafts were transplanted to rat sciatic nerve defects. The rats were then killed after lapses of time. We observed the processes of axonal regeneration using a transmission electron microscope. Regeneration of axons along the inner surface of the Schwann cell basal lamina was clearly seen. These results suggest that, if tubular basal laminae persist, Schwann cells are not always necessary, and axonal regeneration can be induced in the direction toward the basal lamina.

Animals↗
PubMed1995

Microvascular free tissue transfer in oral and maxillofacial reconstruction.

Forty-two patients with head and neck cancer were submitted to microvascular reconstructive procedures. We divided patients in three groups; a first group of 30 patients, in whom the oral floor (8 patients), the part of tongue (14 patients), the lower gingiva (6 patients) and the oropharynx (2 patients) were reconstructed using various sizes of forearm flaps; a second group of 7 patients who underwent buccal mucosa reconstructions with the forearm flaps; and a third group of 5 patients who received rectus abdominis flaps for total tongue reconstruction. Three illustrative cases, one from each group, are presented in detail. Good results were obtained in 39 patients (94%), with both functional and morphological rehabilitation. There were three flap losses due to thrombosis of the microvascular anastomoses. There was no surgical mortality. The average operating time was about 10 hours in total. We concluded that there is a place for these complex procedures in the treatment of selected cases of head and neck tumors.

Adult↗
PubMed1995

Transfer to a nitrocellulose membrane allows of the bone forming activity of bone morphogenetic protein.

When we purify bone morphogenetic protein (BMP), its activity diminishes, and the quantity we are able to extract decreases. It is difficult to evaluate the effects of each of the processes involved in BMP purification because it is unstable. In order to resolve the problem, a modified bioassay method using only slight quantities of BMP which do not decrease its bone-forming activity, is needed. We transferred BMP separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) onto nitrocellulose membranes (NC) and cut out the bands. Then we used each band as implanted material. The NC membrane firmly bound the BMP activity fraction and held it in the implantation area of the mouse thigh. No formation of bone-like tissue was detected histologically at 14 days after the implantation, but, by 21 days after implantation, cartilage like tissue had clearly formed and newly formed bone was seen by 28 days. By implanting BMP transferred to individual NC membranes, we could perform a bioassay easily with small amounts of BMP without any reduction in activity.

Animals↗
PubMed1993

Large cyst formation in pleomorphic adenoma.

The aim of this study was to examine about the etiology of large cyst formation in pleomorphic adenoma from the histopathological standpoint by examining four cases of our own as well as previously reported ones. In the first of our cases, a large cyst wall lined with keratinized squamous epithelium was observed. In the second, a large cyst containing mucinous material was lined with a single cell layer of squamous epithelium-like cells. The third case was a carcinoma in pleomorphic adenoma with some large cysts lined with multiple layers of atypical epithelial cells. In the fourth case, a hemorrhagic portion were seen on a large cyst wall without a lining of epithelial cells. From these histopathological observations and the suggestions of previous authors, we surmised that the large cyst formation in pleomorphic adenoma might originate from the squamous metaplasia of tumor cells and the enlargement of duct-like structures by outstanding secretion from tumor cells or salivary gland tissues, hemorrhagic portions, or necrosis in the malignant tumor.

Adenoma, Pleomorphic↗