Effect of continuous pressure on histopathological changes in denture-supporting tissues

summary The histopathological changes in denture-supporting tissues were studied in relation to continuous pressure exerted through an experimental denture base. The experimental dentures were designed to load continuous pressures (1.5, 3.4 or 4.9 kPa) to the palate of molar region of rat. Histopathological changes caused by the continuous pressure were observed, and the intensity of the pressure was also estimated. A high correlation was observed between the histopathological changes under the denture base and the intensity of the continuous pressure. In groups exposed to 4.9 and 34 kPa, the continuous mechanical pressure caused bone resorption; in 1.5 kPa group, no evidence of bone resorption was observed. The epithelium and lamina propria mucosa under the denture base, which were compressed by the continuous pressure, recovered histopathologically depending on the decrease of the pressure caused by bone resorption; no quantitative recovery of the absorbed bone tissue was observed. No inflammatory change was induced by the continuous pressure. From the histopathological results observed in this study, the possibility of the existence of a threshold for bone resorption induced by continuous pressure was suggested.     

Endoscopic Diagnosis of Intestinal Lipomas

A retrospective endoscopic study of 11 patients with intestinal lipomas was conducted. The patients included 2 with duodenal—, 2 with small intestinal—, and 7 with large intestinal lipomas. Endoscopically, in addition to features common to all submucosal tumors, lipomas often present characteristic findings including a yellowish surface color and softness of the tumor. The yellowish color was noticed in the 6 patients whose tumors were 10 mm and more in size. In the 2 patients with lipomas in the small intestine, the yellowish color was diminished by hemorrhages, inflammation and fibromusculosis in the lamina propria mucosa due to mechanical irritations such as peristalsis and intussusception. Thus, the appearance of the yellow color was related to the size of the tumors and the histological changes in the overlying mucosa. Endoscopic palpation with biopsy forceps aids in making a diagnosis of lipomas; and the cushion sign was noticed in 3 of 4 patients who underwent the palpation. The naked fat sign is pathognornonic but was observed in only 1 patient with a duodenal lipoma, in which the fat tissue was exposed by denuding the mucosa with the biopsy forceps. Scopic biopsies revealed lipomas in 3 patients. Careful observation of the color and palpation during the endoscopic examination are important for making a correct diagnosis and avoiding the unnecessary resection of lesions.     

Dipeptide synthesis catalyzed by aminoacyl-tRNA synthetases from Bacillus stearothermophilus

A new approach to enzymatic peptide synthesis by using aminoacyl-tRNA synthetase (ARS) as a catalyst has been investigated. Four ARSs (AspRS, HisRS, LeuRS and TyrRS) have been purified from a thermophilic bacterium, Bacillus stearothermophilus. By using TyrRS as a catalyst, tyrosine and leucinamide were shown to be condensed in the presence of ATP to give tyrosylleucinamide. In this manner, all of the ARSs investigated catalyzed the peptide synthesis reactions. TyrRS did not have strict specificity for the amino acid derivatives used as substrates and even D-amino acids were incorporated into peptides fairly easily in this enzymatic reaction. Preparative scale synthesis of L-Tyr-L-LeuNH₂ was carried out and from this the scope and limitation of this new enzymatic reaction as a tool to the peptide synthesis has been described.     

The Role of Surgical Resection in the Management of Small Cell Carcinoma of the Lung

To assess the role of surgical resection in the management ofsmall cell carcinoma of the lung, experience with 118 patientswho were treated between 1973 and 1985 was reviewed. Twenty-fivepatients underwent surgical resection followed by combinationchemotherapy in all except one. The remaining 93 pa tients weretreated by combined chemotherapy and radiation therapy. The 5-year survival rate for patients with stage I disease undergoingsurgical resection was 50.8%. For all 25 patients operated on,the 5-year survival rate was 30.7%. In the patients not operated on, only those with complete responsehad long-term survival, for whom the 5-year survival rate was11.9% We consider that surgical resection is definitely indicatedin patients with stage I disease. If the response to initialchemotherapy is very good, patients with stage 11 or T3N0M0disease also probably should receive resection. Patients withN2 disease are not candidates for resection, unless distantmetastases are controlled completely by intensive chemotherapy.     

A multiparametric analysis of occlusal and periodontal jaw reflex characteristics in young adults with normal occlusion

summary Periodontal jaw reflex, duration of percussion sounds, tooth mobility, and time-moment analysis of occlusal contacts by the T-scan system was recorded in nine periodontally healthy volunteers. The results showed that (i) reflex responses to the pressure applied to the uppercentageral incisors in the lingolabial direction varied, depending on the background jaw-clenching force (BCF) of the same-sided first molars. The BCF levels to elicit excitatory reflexes were 6–8Kgf, and inhibitory reflexes were clearly elicited with a BCF of l0Kgf and beyond. (ii) Duration of percussion sounds via an occlusal sound analyser (4.73–4.84mS: upper first molars. 4.89–5.00mS: uppercentageral incisors) and tooth mobility using a 'Periotest' (3.3–3.5: upper first molars, 5.5–5.6: uppercentageral incisors) showed a normal value. (iii) The time moments of occlusal contacts were symmetrical toward the midsagittal axis of the occlusal plane. The centre of the anterioposteriol occlusal contacts was located in the first molar regions.     

Extraperitoneal laparoscopic retroperitoneal lymph node dissection in supine position after chemotherapy for advanced testicular carcinoma

AIM: To evaluate the feasibility and usefulness of extraperitoneal laparoscopic retroperitoneal lymph node dissection (RPLND) in the supine position after chemotherapy for advanced testicular carcinoma. METHODS: Three patients with advanced testicular cancer underwent chemotherapy. Although serum markers were decreased compared with the normal range, residual masses requiring surgical resection were recognized by computed tomography scanning. We applied extraperitoneal laparoscopic RPLND. The patients were placed in the supine position and the first trocar was inserted two finger widths medial to the anterior iliac spine. The retroperitoneal space was dilated using a preperitoneal distention balloon. Two more ports were inserted into the retroperitoneal space and surgery proceeded thereafter. RESULTS: The residual tumors were completely resected by laparoscopy. The procedure required 250-310 min and the bleeding volume was below 50 mL. Although the histopathological findings consisted only of necrosis in all of the patients, one patient recurred at the same place. CONCLUSIONS: Extraperitoneal laparoscopic RPLND in the supine position for residual tumors after chemotherapy is technically feasible and useful in terms of postoperative recovery. With regard to cancer control, further evaluation should be necessary.     

Antiviral effect of lymphoblastoid interferon-alpha on hepatitis C virus in patients with chronic hepatitis type C

Abstract To study the antiviral effect of lymphoblastoid alpha interferon (IFN) on hepatitis C virus (HCV) we conducted a randomized, controlled trial on 80 patients with chronic hepatitis C using three different doses. Patients were randomly assigned to treatment with 1, 3 or 6 million units of lymphoblastoid IFN-alpha daily for 2 weeks. To assess the antiviral effect of IFN, the amount of HCV present in the serum was estimated by competitive nested polymerase chain reaction (PCR) before and after 2 weeks of treatment. The multiple logistic analysis was used to evaluate factors associated with virus clearance, adjusting the imbalance in predictive factors among patients. Hepatitis C virus became negative as assessed by nested PCR after therapy in 26, 50 and 63% of patients receiving 1, 3 and 6 mega units, respectively. Hepatitis C virus was cleared more often in patients having initially low (< 10⁵/mL) amounts of virus. No significant decrease in the amount of virus was observed in the untreated, control group. Patients without bridging fibrosis in liver histology and with HCV genotypes other than K1 (type II) tended to respond well. These results indicate that lymphoblastoid IFN-alpha suppresses HCV in a dose dependent manner. Higher initial virus amounts, bridging fibrosis and genotype K1 were factors associated with poor response.     

Protective Effects of Dilazep and its Derivative K-7259 on the Haemolysis Induced by Amphiphiles in Rat Erythrocytes

The effects of dilazep and K-7259, a dilazep derivative, on the haemolysis (as evidenced by release of haemoglobin) induced by palmitoyl-l -carnitine (PAL-CAR) or palmitoyl 1-α-lysophosphatidylcholine (PAL-LPC) have been determined in rat erythrocytes. At concentrations above the critical micelle concentration both PAL-CAR and PAL-LPC induced haemolysis; the concentrations of PAL-CAR and PAL-LPC producing 50% haemolysis were approximately 13 and 14 μm , respectively. The 50% haemolysis induced by PAL-CAR or PAL-LPC was attenuated by dilazep (1, 10 or 100 μm ) but not at the highest concentration used (1 mm ). K-7259 attenuated the 50% haemolysis induced by PAL-CAR or PAL-LPC at concentrations ranging from 1 μm to 1 mm . Similarly, dilazep (1 to 100 μm ) and K-7259 (1 μm to 1 mm ) significantly or insignificantly attenuated the 25% and 75% haemolysis induced by PAL-CAR or PAL-LPC. Neither dilazep nor K-7259 affected micelle formation by PAL-CAR or PAL-LPC, nor, at concentrations of 1 and 10 μm , did they attenuate the haemolysis induced by osmotic imbalance (hypotonic haemolysis). These results suggest that both dilazep and K-7259 protect the erythrocyte membrane from the damage induced by PAL-CAR or PAL-LPC. The protective effects of dilazep and K-7259 are mediated by some mechanism other than prevention of micelle formation or protection of the erythrocyte membrane against osmotic imbalance.