Microindentation of cartilage before and after articular loading in a bioreactor: assessment of length-scale dependency using two analysis methods.

Background: Microindentation is a technique with high sensitivity and spatial resolution, allowing for measurements at small-scale indentation depths. Various methods of indentation analysis to determine output properties exist. Objective: Here, the Oliver-Pharr Method and Hertzian Method were compared for stiffness analyses of articular cartilage at varying length-scales before and after bioreactor loading. Methods: Using three different conospherical tips with varying radii (20, 100, 793.75 µm), a bioreactor-indenter workflow was performed on cartilage explants to assess changes in stiffness due to articular loading. For all data, both the Oliver-Pharr Method and Hertzian Method were applied for indentation analysis. Results: The reduced moduli calculated by the Hertzian Method were found to be similar to those of the Oliver-Pharr Method when the 20 µm tip size was used. The reduced moduli calculated using the Hertzian Method were found to be consistent across the varying length-scales, whereas for the Oliver-Pharr Method, adhesion/suction led to the largest tip exhibiting an increased average reduced modulus compared to the two smaller tips. Loading induced stiffening of articular cartilage was observed consistently, regardless of tip size or indentation analysis applied. Conclusions: Overall, geometric linearity is preserved across all tip sizes for the Hertzian Method and may be assumed for the two smaller tip sizes using the Oliver-Pharr Method. These findings further validate the previously described stiffening response of the superficial zone of cartilage after articular loading and demonstrate that the finding is length-scale independent.

Perineal reconstruction of female conjoined twins.

BACKGROUND/PURPOSE: Conjoined twins are some of the most challenging patients faced by surgeons. Pygopagus and ischiopagus twins present particular gastrointestinal and genitourinary reconstructive challenges. This study reviews the authors' experience with the perineal reconstruction of these types of conjoined twins. METHODS: Retrospective analysis was performed for 3 sets of female conjoined twins undergoing separation between 1999 and 2001. Particular attention was given to the separation and reconstruction of the distal gastrointestinal and urogenital structures. RESULTS: Three sets of female conjoined twins underwent successful separation 2 pygopagus, one ischiopagus tripus) with 5 surviving infants. The sixth infant died of congenital anomalies incompatible with life. Four of the 5 surviving infants had diverting enterostomies. Two of these enterostomies have been closed. Perineal reconstruction consisted of anoplasty (5 of 5), vaginoplasty (4 of 5), and urethroplasty (4 of 5). Although fecal and urinary continence are not completely measurable at this age (<3 years), all 5 survivors void spontaneously. Three infants with intestinal continuity have apparently normal defecation without the need of a bowel regimen. CONCLUSIONS: With careful preoperative planning and a multidisciplinary team of pediatric surgeons and urologists, satisfactory reconstruction and functional outcome of the female perineum can be achieved in conjoined twins.

Acute community-acquired pneumonia: current diagnosis and treatment.

1. Diagnosis of acute community acquired pneumonia is based on the history, physical examination, and chest x-ray. With respect to diagnosis, the clinician should ask, (1) Is the problem pneumonia or something else? (2) Is the pneumonia often treated empirically with a macrolide (erythromycin, clarithromycin, or azithromycin), a "respiratory quinolone" (levofloxacin, moxifloxacin, gatifloxacin, or gemifloxacin) or doxycycline. 4. Concern has expressed that use of quinolones as monotherapy for pneumonia may promote the emergence of resistant strains. However, the quinolones are more reliable than the macrolides and doxycycline against pneumococcal strains that exhibit reduced susceptibility to penicillin G. 5. Appropriate diagnostic studies for patients with moderately-severe to severe pneumonis include sputum Gram's stain and culture (for those patients who expectorate purulent sputum), blood cultures, and acute serum sample, and --in some circumstnaces--urinary antigen test for Legionella pneumophila. 6. Appropriate initial therapy for patients requiring hospitalization includes a third-generation cephalosporin (such as ceftriaxone or cefotaxime) plus a macrolide or a quinolone.

Osler usque ad mare: the SS William Osler.

William Osler's connections with the sea included a strong family history of seafaring, his own transatlantic crossings (of which there were at least 32) and the occasional use of nautical imagery in his inspirational writings. An unusual Oslerian connection with the sea emerged after his death in the form of a World War II Liberty ship. Through the SS William Osler and its sister ships, Osler was symbolically reunited with colleagues associated with the early days of the Johns Hopkins Hospital. The William Osler circumnavigated the globe in 1943 without engaging the enemy. She was then converted into an army hospital ship and renamed the USHS Wisteria.

Treatment of pneumococcal pneumonia: the case for penicillin G.

Although widely endorsed for specific treatment of pneumococcal pneumonia, penicillin G is seldom used for this purpose in clinical practice for at least three reasons: (1) concern about penicillin-resistant Streptococcus pneumoniae (PRSP) strains; (2) the difficulty of making an early etiologic diagnosis of pneumonia; and (3) lack of a clear consensus about the optimum dosage. Continuous infusion of 20-24 million units of penicillin per day provides serum levels of 16-20 microg/mL in persons with normal renal function. These levels easily exceed the minimum inhibitory concentrations (MICs) of penicillin G against most PRSP strains (4 microg/mL), which are actually strains with reduced susceptibility to penicillin. High-dose penicillin G therapy has not been shown to be therapeutically ineffective against pneumonia due to PRSP strains. However, the extent of penicillin resistance warrants continued monitoring, because strains exhibiting extremely high-level resistance (MIC > or = 8 microg/mL) would probably respond poorly if at all. Development and use of rapid, sensitive, specific ways to diagnose pneumococcal pneumonia could extend the usefulness of penicillin G, thus postponing the emergence of resistance to other antibiotics.