Electron microscopy of developing calvaria reveals images that suggest that osteoclasts engulf and destroy osteocytes during bone resorption

Summary It is generally accepted that osteoclasts are responsible for the breakdown and removal of bone matrix constituents. However, very little is known about the fate of osteocytes during bone resorption. In the present study we have examined sites of bone destruction in calvaria of young rats aged 4–9 days in the hope of obtaining information on the fate of osteocytes. Decalcified glutaraldehyde-formaldehyde-fixed specimens were prepared for ultrathin section electron microscopy. When sequentially arranged, the images obtained suggest that osteoclasts engulf and destroy osteocytes during bone degradation. We propose that the following sequence of events takes place when a lacuna is opened up by an osteoclast: (1) When the osteoclast comes in contact with an osteocyte, the villi of the ruffled border become flat and broad. (2) Long osteoclastic extensions surround the osteocyte. (3) The osteocyte is subsequently internalized with apparent degradation.     

Postischemic renal dysfunction: the limited role of xanthine oxidase-generated oxygen free radicals

Oxygen free radicals (OFRs) generated during reperfusion are putative mediators of postischemic renal dysfunction. To address this issue, the renal response to ischemia and reperfusion was compared to the response to OFR generation without ischemia. Isolated rat kidneys were perfused at 37 degrees C and 90-100 mm Hg with an asanguinous modified Krebs' buffer. Kidneys were subjected to 30 min of ischemia followed by reperfusion or to OFRs generated by combining 25 mumole hypoxanthine with 1 unit xanthine oxidase. Both insults caused a 50% increase in vascular resistance. This was accompanied by a 30% reduction in perfusate flow rate and an 80% reduction in glomerular filtration and urine flow rates. The OFR scavengers, superoxide dismutase (SOD, 250 units/ml) and catalase (CAT, 500 units/ml), prevented these alterations after OFR generation but not after 30 min of ischemia and reperfusion. SOD and CAT also afforded no protection against the less severe dysfunction observed after 10 or 20 min of ischemia and reperfusion. OFRs do not appear to be prominent mediators of postischemic renal dysfunction; other factors, probably associated with ischemia must be primarily responsible.     

Multiple primary lung cancers. Results of surgical treatment

During a 13-year period, multiple primary lung cancers were diagnosed in 80 consecutive patients. Forty-four patients had metachronous cancers. The initial pulmonary resection was lobectomy in 36 patients, bilobectomy in 3, pneumonectomy in 1, and wedge excision or segmentectomy in 4. The second pulmonary resection was lobectomy in 16 patients, bilobectomy in 2, completion pneumonectomy in 7, and wedge excision or segmentectomy in 19. There were two 30-day operative deaths (mortality rate, 4.5%). Actuarial 5- and 10-year survival rates after the first pulmonary resection for stage I disease were 55.2% and 27.0%, respectively. Five-year and 10-year survival rates for stage I disease after the second pulmonary resection were 41.0% and 31.5%, respectively. The remaining 36 patients had synchronous cancers. The pulmonary resection was lobectomy in 18 patients, bilobectomy in 3, pneumonectomy in 10, and wedge excision or segmentectomy in 8. There were two 30-day operative deaths (mortality rate, 5.6%). Actuarial overall 5- and 10-year survival rates after pulmonary resection were 15.7% and 13.8%, respectively. We conclude that an aggressive surgical approach is safe and warranted in most patients with multiple primary lung cancers and that the presence of synchronous primary cancers is ominous.     

Ductal adenoma of the breast

Ductal adenoma is a recently described benign tumour of the breast that can be mistaken for carcinoma in both frozen and paraffin sections. Such a case is presented. Fortunately a mastectomy was not performed, but the patient did undergo axillary node dissection. Surgeons and pathologists should familiarize themselves with this lesion so that patients do not have to undergo unnecessary mastectomies and axillary node dissections.     

Lyme disease presenting as urinary retention

We report a case of Lyme disease that presented with urinary retention. The individual then experienced lower extremity paralysis. Paralysis and urinary retention resolved with intravenous ceftriaxone antibiotic. To our knowledge this is the first report of a urological manifestation as the initial clinical presentation of Lyme disease. Recognition of clinical symptoms and urological complications of Lyme disease also are discussed.     

Prevention of microbial contamination of surgical wounds

Comparative analysis of 3707 operations on the organs of the abdominal cavity has shown the significant advantage of the suggested by the authors method for intraoperative wound protection with latex rubber in combination with placing the longitudinal removable sutures over the subcutis and skin, and dressing-free management of the wounds in prophylaxis of the postoperative purulent wound complications. After 310 operations of different contamination degree performed with the use of the given method, no suppuration of the operative wounds was noted.