Biocompatibility of zirconia dispersed hydroxyapatite ceramics

Because of the lack of adequate strength and toughness, hydroxyapatite (HA) ceramic can not be used for a substitute for a bone and joint despite its excellent affinity for the bone. The present authors have succeeded in producing a new type of HA ceramic containing zirconia. This new ceramic material is superior to ordinary HA ceramic in quality and exceeds compact bone in bending strength and fracture toughness. The Young's modulus was about 3-4 times greater than that of compact bone. The new ceramic material contained either 1.6 or 50% of zirconia by volume and was produced using a special technique to disperse the metal dioxide. In order to assess their affinity for the bone, the new ceramic materials were implanted into rabbit femurs. Sections of the bones removed at different times after operation were prepared without decalcification and subjected to optical microscopy, scanning electronmicroscopy (SEM), and electron-probe X-ray microanalyser (EPMA). The formation of direct chemical bonds with the bone was seen without intervening membrane. Thus, the new ceramic material was shown to have an excellent affinity for the bone, comparable to that of ordinary HA ceramic.     

REOPERATION FOR RECURRENT CORONARY ARTERY DISEASE: RESULTS OF 200 CONSECUTIVE CASES

Background : It is well known that reoperation for recurrent coronary artery disease is more difficult than primary coronary artery bypass grafting. However, it is possible to reduce the morbidity and mortality of reoperation to the same level as the initial procedure with careful surgical technique. Methods : A retrospective study of the first 200 patients who underwent redo coronary bypass grafting was undertaken. Results : In the first 200 cases of redo coronary bypass grafting at St George Hospital, Sydney (August 1986–January 1995), there were five in-hospital deaths (2.5%). There was one case of sternal infection (0.5%), which required surgical debridement, three cases of stroke (1.5%), one case of postoperative bleeding (0.5%), which required a return to theatre and six cases (3%) required mechanical ventilation for more than 24h. The need for major postoperative support (such as intra-aortic balloon pumping/adrenaline infusion) was significantly affected by the degree of urgency and the degree of pre-operative ventricular impairment. Conclusions : The mortality rate of redo coronary artery bypass grafting in this series is similar to that of primary surgery described in other reports.     

Two cases of subcortical hemorrhage with asymptomatic occlusion of the main trunk of cerebral artery

We report two cases of asymptomatic occlusion of the main trunk of the cerebral artery associated with subcortical hemorrhage in the area fed by collateral circulation. The first patient, a 51-year-old female who had suffered from untreated hypertension for 20 years, was hospitalized in a state of coma. Computed tomography (CT) revealed a subcortical hemorrhage in the right parietal lobe as well as subdural and subarachnoid hemorrhages. Cerebral angiography disclosed occlusion of the right internal carotid artery at its origin. The region normally supplied by the right anterior (ACA) and middle cerebral (MCA) arteries was supplied instead by the posterior cerebral artery via leptomeningeal anastomosis. The hematoma was removed and the patient was discharged 1 month later. The second patient was a 54-year-old female who had suffered from uncontrollable hypertension for 27 years and was hospitalized after sudden development of stupor, right hemiparesis and motor aphasia. CT demonstrated a subcortical hemorrhage in the left parietal lobe. Cerebral angiography disclosed occlusion of the left MCA at its origin. The area normally fed by the left MCA was supplied instead by the ACA by way of leptomeningeal anastomosis. One month after operation the patient was transferred to another hospital for rehabilitation of right hemiparesis. Both of these middle-aged women had long-standing hypertension. The hemorrhages were thought to result from rupture of the leptomeningeal anastomosis, which had developed as collateral vessels. It is probable that the relatively weak leptomeningeal anastomosis could no longer withstand the increased blood flow brought on by the hypertension.     

Changes in polyamine metabolism in rat liver after oral administration of alpha-naphthylisothiocyanate

Changes in the levels of urea cycle enzymes and polyamine metabolism in the liver of rats treated with alpha-naphthylisothiocyanate (ANIT), an inducer of experimental cholestasis, were studied. Activities of arginase increased approximately two-fold compared to the control values during the period of 24-72 hours after oral administration of ANIT (100 mg/kg), while activities of ornithine carbamyltransferase and ornithine aminotransferase decreased. The activity of ornithine decarboxylase was elevated by approximately 20- and 10-fold at 12 and 60 hours, respectively, after ANIT administration. Putrescine concentration doubled 24-48 hours after the ANIT administration, but spermidine level rose more slowly and reached the level of 1.5-fold of the control level in 36-72 hours. Spermine concentration decreased initially but increased in 96 hours. These results suggest that the increased activity of urea cycle accounts for the increase in the ornithine content and that the putrescine and spermidine acts as the initiator of recovery of the liver damaged by ANIT treatment.     

Clinical report: cylindrical cell papilloma of the paranasal sinus

We report a case of cylindrical cell papilloma of the paranasal sinuses. This tumor originated in the medial wall of the left maxillary sinus of a 69-year-old man and extended to the surrounding tissues. Pathological study of tissue sections from the tumor showed typical findings of cylindrical cell papilloma with no evidence of associated malignancy. Histochemical and electron microscopic examinations revealed a large number of mitochondria in the cytoplasm of the tumor cells. The tumor was removed through a Denker's approach. The patient did well following surgery and there has been no sign of recurrence in a 2-year follow-up study.     

Effects of renin-angiotensin system blockade on macrophage infiltration in patients with hypertensive nephrosclerosis.

The mechanisms of hypertensive nephrosclerosis are not fully understood. In experimental models of the disease, inflammatory reactions such as macrophage infiltration play an important role. In human hypertensive nephrosclerosis, however, there have been few studies examining the role of inflammation histologically. We investigated whether the number of infiltrating macrophages was increased in human hypertensive nephrosclerosis, and evaluated the effects of a blockade of the renin-angiotensin system on clinical and histological findings. We examined macrophage infiltration using immunohistochemistry in renal biopsy specimens obtained from 16 patients with hypertensive nephrosclerosis, 5 patients with IgA nephropathy, 5 patients with membranous nephropathy, and 5 patients with minimal change nephrotic syndrome. The number of infiltrating macrophages in glomeruli was significantly larger in the patients with hypertensive nephrosclerosis than in those with minimal change nephrotic syndrome. The patients with hypertensive nephrosclerosis were divided into groups based on their use of antihypertensive agents at the time of renal biopsy. We investigated the effects of antihypertensive agents on clinical findings, macrophage infiltration, and monocyte chemoattractant protein-1 expression. There was no difference in clinical findings between the hypertensive groups. The numbers of infiltrating macrophages and monocyte chemoattractant protein-1-positive cells in glomeruli were significantly smaller in patients treated with an angiotensin-converting enzyme inhibitor or angiotensin II type 1 receptor blocker, whereas calcium channel blockers had no influence on histological findings. In conclusion, inflammation is involved in the progression of human hypertensive nephrosclerosis and the inflammatory process is inhibited by blocking the renin-angiotensin system.     

Retroperitoneal primary mucinous adenocarcinoma with a mural nodule of anaplastic tumor: a case report and literature review.

A 38-year-old female presented with a lower abdominal mass. During the operation the mass was found to be retroperitoneal and was excised. Gross examination revealed a mucin-containing cystic lesion with a mural nodule. On microscopic examination, the cystic areas were lined by an invasive mucinous adenocarcinoma and the nodule was composed of an anaplastic sarcomatoid tumor that was immunoreactive for cytokeratin. This present case is the 21st example of a retroperitoneal primary mucinous cystadenocarcinoma and the fourth with a mural nodule. Three of four cases with a mural nodule, including our case, had a rapidly fatal outcome.     

Aging gracefully: a retrospective analysis of functional status in Okinawan centenarians.

OBJECTIVE: This study retrospectively explored the late-life functional status of Okinawan centenarians. METHODS: Activities of daily living were measured retrospectively at five time points (10, 5, 3, and 1 year prior and present) for 22 centenarians in relation to seven physical, two sensory, and two cognitive functions using the Inoue Index. RESULTS: In all, 82% of individuals were still functioning independently at a mean age of 92 years and almost two-thirds were still functioning independently at a mean age of 97 years. CONCLUSION: Preliminary analyses suggest high functional status in Okinawan centenarians throughout their 90 s. The genetic and environmental factors contributing to this successful aging phenomenon deserve further investigation.