Wear of denture teeth by use of metal plates. Part 3: Abrasive wear of posterior teeth and wear of opposing metal plates

An in vitro evaluation of abrasive wear resistance of high-strength denture (HS) teeth and wear of metal plates (Pd alloy) on the opposing side was conducted. A total of 8 types of teeth were used in the experiments including 3 types of HS teeth, 3 types of conventional plastic denture (PL) teeth, porcelain teeth and metal teeth (Pd alloy). Sliding-induced wear tests were conducted by sliding these teeth over the metal plates. Abrasive wear resistance of the teeth was evaluated in terms of wear depth and weight loss. A comparison of wear depth showed that the abrasive wear resistance of HS teeth was 4.7 times that of PL teeth, 0.7 times that of porcelain teeth and 8.3 times that of metal teeth. Weight loss showed that the abrasive wear resistance of HS teeth was 3.3 times that of PL teeth, 0.2 times that of porcelain teeth and 11.4 times that of metal teeth. The weight loss of the metal plates was minimal when they slid over HS teeth, but increased in the order PL teeth, porcelain teeth and metal teeth.

Wear of denture teeth by use of metal plates. Part 2: Abrasive wear of posterior teeth

An in vitro study was conducted to evaluate the abrasive wear resistance of high-strength denture teeth (HS teeth). Eight types of specimen were used in the experiments; 3 types of HS teeth, 3 types of conventional plastic denture teeth (PL teeth), porcelain teeth and metal teeth. Sliding-induced wear tests were conducted by sliding the samples on a metal plate. The abrasive wear resistance of the samples was evaluated in terms of wear depth, weight loss and SEM observation. Comparison of wear depth showed that abrasive wear resistance of HS teeth was 4.7 times that of PL teeth, 0.7 times that of porcelain teeth and 8.3 times that of metal teeth. In terms of weight loss, the corresponding values were 3.3-fold, 0.2-fold and 11.4-fold, respectively.

Carcinoid tumor of the pancreas with obstructive pancreatitis

A case of primary pancreatic enterochromaffin cell (EC cell) carcinoid tumor in a 66-yr-old Japanese man is presented. The markedly dilated main pancreatic duct was noticed at the time of an incidental ultrasonogram during hospitalization for diabetes mellitus. Endoscopic retrograde pancreatography showed stenosis of the main pancreatic duct at the body of the pancreas and dilated pancreatic ducts distal to the obstruction. A distal pancreatectomy was performed, together with splenectomy. Macroscopically, the main pancreatic duct was compressed by a fibrous mass around the duct, and the pancreatic ducts distal to the tumor were markedly dilated. Histologically, the tumor was composed of uniform round cells, proliferating in small nests or trabeculae. The tumor cells were strongly positive with both Grimelius and Fontana-Masson stains. The immunohistochemical study disclosed the tumor cells to be positive for serotonin and chromogranin. This is a rare case of primary pancreatic EC cell carcinoid tumor with obstructive pancreatitis.

Pathology of carcinoma of the gallbladder

A clinicopathologic study of 40 cases of carcinoma of the gallbladder is presented. Twenty-six cases resected were assessed retrospectively with respect to the operative procedures employed and the results based on the pathologic findings from the resected specimens. The relationship between clinical features, macroscopic forms of tumor, histological types, liver invasion, and lymph node metastasis were investigated. Papillary, papillary infiltrative and nodular forms were classified as either papillary adenocarcinoma or well-differentiated tubular adenocarcinoma and invasion of the liver and lymph node metastasis were rare. Frequent lymph node metastasis was encountered in the nodular infiltrative form and invasion of the liver was frequently present in the infiltrative form. Invasion of the liver, lymph node metastasis, and the presence of gallstones were less frequent in papillary adenocarcinoma. In contrast, moderately-differentiated tubular adenocarcinoma frequently had lymph node metastasis. Invasion of the liver and lymph node metastasis were, however, present regardless of the histologic types and were more related to the extent of subserosal involvement present. A female preponderance was noted in poorly-differentiated adenocarcinoma. The main reasons for surgery being limited to exploratory laparotomy only or palliative procedures included carcinoma infiltration into the hepatoduodenal ligament, carcinoma extension to the neighboring structures, multiple liver metastases, peritoneal dissemination, large liver invasion, and multiple metastases to the paraaortic lymph nodes.

Distribution of mouse interferon-beta in normal and brain tumour-bearing mice

The distribution of 125I-labelled recombinant mouse interferon-beta (rMuIFN-beta) in normal and glioma (203 glioma) bearing mice was studied by radioassay and macro-autoradiography at 15 and 30 min after a single intravenous injection. The level of rMuIFN-beta in the spleen was about 20-fold higher than in serum. Concentrations higher than the serum level was detected in the lung, liver and kidney. The concentration of rMuIFN-beta in the brain was 8% of the serum level and the concentration in the glioma 30 min after administration was about 10-fold higher than in normal mouse brain. Macro-autoradiographic study demonstrated a wide distribution range and selective uptake in glioma tissue. Furthermore, we found that mouse gliomas were sensitive to mouse IFN-beta. Our findings demonstrate that in the mouse glioma model, intravenously administered interferon reaches the tumour.

Wear of artificial denture teeth by use of toothbrushes. Part 1: Abrasive wear of anterior teeth

High-strength denture teeth (HS teeth) were developed in order to improve the hardness and wear resistance of conventional plastic denture teeth (PL teeth), while retaining their feature of easy occlusal adjustment. The objective of this study was to evaluate the abrasive wear resistance of HS teeth. We conducted wear tests and measured surface roughness using six types of anterior artificial teeth, i.e., three types of HS teeth and three types of PL teeth, the latter serving as the control. The results of the toothbrush abrasion test revealed that the HS teeth had about 5 times greater wear resistance than the PL teeth. It was also found that the type of artificial teeth and the number of abrasive wear-testing strokes had a significant (P less than 0.05) influence on the surface roughness of artificial teeth.

Gallium scanning and tomography in the preoperative evaluation of lung cancer

Discrepant reports on the utility of gallium scanning in the preoperative evaluation of patients with lung cancer prompted a prospective study of the test. The authors studied 47 patients with lung cancer who underwent preoperative gallium scanning and frontal tomography of the mediastinum. Both tests were found to be most accurate in predicting the presence of mediastinal metastases among patients with squamous cell carcinoma. Both test may help direct surgical planning in patients with known squamous cell carcinoma of the lung.