The interaction of the zone of calcified cartilage and subchondral bone in osteoarthritis.

The zone of calcified cartilage (ZCC) forms an important interface between cartilage and bone for transmitting force, attaching cartilage to bone, and limiting diffusion from bone to the deeper layers of cartilage. The height of the ZCC is a relatively constant percent of articular cartilage and the height is maintained by a balance between progression of the tidemark into the unmineralized cartilage and changing into bone by vascular invasion and bony remodeling. During its formation, the cells that form the ZCC have properties similar to the cells of the growth plate. In the adult, the ZCC becomes quiescent but not inactive. The ZCC may be reactivated in osteoarthritis and may progressively calcify the unmineralized cartilage. This might contribute to cartilage thinning which would increase the concentration of forces across the uncalcified cartilage leading to more damage. Although the subchondral bony plate remodels extensively in osteoarthritis, there is little evidence that a change in the biomechanics of the plate directly initiates the osteoarthritic process in cartilage. However, increased repair by endochondral ossification of vertical cracks in the ZCC that penetrate into the marrow space could contribute to progression via changes in the ZCC.

In vitro evaluation of iris chafe protection afforded by hydrophilic surface modification of polymethylmethacrylate intraocular lenses.

An in vitro iris chafe test was developed to evaluate possible differences in abrasive interaction of various intraocular lens (IOL) materials with the posterior surface of the iris. The materials that were compared in initial tests with rabbit irides were high molecular weight polymethylmethacrylate (PMMA), the primary IOL material in current use, and surface-modified PMMA, which had a permanent, chemically bound, hydrophilic, polymer surface. Scanning electron microscopy, light microscopy, and examination of histological sections were used to assess tissue damage. A "window defect" type of abrasive damage was observed by light microscopy for PMMA lenses and is very similar in appearance to that seen for iris abrasion by human implants when viewed in vivo in slitlamp examinations. Results for both pigmented and albino rabbit irides indicate a reduction in abrasive insult to the external iris basement membrane and underlying pigment epithelium by the hydrophilic surface modification of PMMA. These results are consistent with our observation of a major reduction in corneal endothelium damage on contact with the hydrophilic surface-modified PMMA as compared with PMMA itself. This in vitro iris abrasion test, therefore, appears to be a useful technique for future evaluation of IOL surface properties.

[Morbidity of the donor site of the dorsalis pedis flap]. / Morbidität des Spenderbezirkes von Dorsalis pedis-Lappen.

Detailed information on the dorsalis pedis flap donor-site morbidity is still lacking. In a retrospective analysis, wound-healing, cosmesis, mobility, stability, and thermographic studies of the feet were investigated. The results show a high donor-site morbidity of the dorsalis pedis flap. Indications and alternative methods are discussed.

Mothers are still mortal.

The origin, background, and mechanism of operation of the Maternal Mortality Study Committee in Wisconsin is outlined. Its value as a teaching vehicle is emphasized. Trends in maternal mortality in Wisconsin and the continued decline are presented, with 45 per 100,000 live births in 1953 to 9.2 per 100,000 live births in 1975. An appeal for standardization of terms and definitions and a continuation of these studies in each state is made. Study committees in many states are inactive. It is suggested that chairmen of maternal mortality committees in many states are inactive. It is suggested that chairmen of maternal mortality committees and representatives meet in geographic areas comparable to Districts of The American College of Obstetricians and Gynecologists to compare trends and statistics. Hemorrhage, once considered the important cause, has decreased from 56.4% of maternal loss to a low of 12.1% in 1975. Presently, a category listed as "other causes"--that is, other than hemorrhage, sepsis, and toxemia--account for approximately 60% of deaths. This group includes anesthesia, emboli and coincidental disease involving kidneys, heart, malignancy, and diabetes. An appeal is made to continue these studies.

Culdotomy: a method of evaluating the pelvis.

PIP: This report is based on 502 culdotomies performed by the author and his associates. The method is commonly but erroneously called colpotomy . Of the 502 culdotomies, 293 were performed for tubal interruption, 209 were done for diagnosis and other surgical procedures. There were 9 complications, 3 requiring abdominal intervention. The operation is an incision into the cul-de-sac and is a practical means of investigating the pelvis to determine the status of the uterus, tubes, and ovaries. It has been the first step in vaginal hysterectomy technique. In the uncomplicated cases patients for tubal interruption were discharged from the hospital 42 hours after admission. No pregnancies have followed. W hen the operations were done for other purposes the hospital stay averag ed 72-96 hours. Preliminary evaluation includes a Papanicolaou smear. Chronic or recent pelvic inflammatory disease must be eliminated. Preoperative vaginal preparation with Gantrisin cream has been used. The operation may be done with a general or local anesthetic, preferably with an analgesic such as Demerol or morphine. Iv lactated Ringer's solution is also given and Valium at intervals. A transverse incision is made through the cul-de-sac. Unclotted blood encountered may indicate the existence of an ectopic pregnancy. Details of the technique are described. Approximately 30 minutes are required for the operation. Postoperatively the patient uses the Gantrisin cream 3 times weekly. Culdotomy is considered an efficent and practical approach to the pelvis for diagnosis and therapy. Discussion of the paper by others follows.^ieng

Cefotaxime desensitization.

We report the successful desensitization to cefotaxime in a patient with severe lumbar osteomyelitis of unknown bacteriology and hypersensitivity to the drug. Desensitization was carried out because of the unknown bacteriology, the favorable response to cefotaxime at that time, and hypersensitivity to other antibiotics. On the first day the patient received 1 mg cefotaxime intravenously. The dose was increased for 13 successive days to 4 g cefotaxime intravenously per day. No allergic reaction occurred during desensitization or within 4 weeks of observation under this therapy. Patients with severe infections of unknown bacteriology might benefit from desensitization if therapy with a second-choice antibiotic is impossible.

Reproducible erythroid aplasia caused by mycophenolate mofetil.

Anemia secondary to mycophenolate mofetil (MMF) was recently described in experimental animals. A clinical association between MMF and anemia has been observed, but there are no proven reports. We describe a girl with chronic graft failure who developed erythroid aplasia under immunosuppression with MMF. She showed prompt resolution when MMF was discontinued and a recurrence of this clinical course when MMF was restarted. As re-challenge with a medication is the most definitive approach for showing a direct relationship between the drug and the side effect, this case clearly demonstrates that MMF can cause erythroid aplasia.