Cartilage mechanics in the guinea pig model of osteoarthritis studied with an osmotic loading method

OBJECTIVE: To determine the material properties of articular cartilage in the Hartley guinea pig model of spontaneous osteoarthritis. METHODS: Cartilage-bone samples from the medial femoral condyle and tibial plateau of 12 month-old guinea pig knees were subjected to osmotic loading. Site-matched swelling strains and fixed charge density values were used in a triphasic theoretical model for cartilage swelling to determine the modulus of the cartilage solid matrix. The degree of cartilage degeneration was assessed in adjacent tissue sections using a semi-quantitative histological grading scheme. RESULTS: Decreased values for both moduli and surface zone fixed charge density were associated with increasing grades of cartilage degeneration. Decreases in moduli reflect damage to the collagen matrix, which give rise to greater swelling strains. CONCLUSION: Histological evidence of cartilage degeneration was associated with impaired cartilage mechanics in the aging Hartley guinea pig.     

Guaifenesin as a treatment for primary dysmenorrhea

BACKGROUND: Dysmenorrhea is highly prevalent and causes much work loss and discomfort. A treatment with a new mechanism of action could benefit women of menstruating age. A study was undertaken to assess the efficacy of guaifenesin as a treatment for primary dysmenorrhea because of its effects of cervical dilation and cervical mucous thinning. METHODS: Thirty-four subjects with primary dysmenorrhea were enrolled in a double-blind, placebo-controlled study. Three treatment surveys measured 10 symptoms (lower abdominal pain, general abdominal pain, back pain, headache, nausea, diarrhea, constipation, menstrual flow, weakness, and activities of daily living) on a 100-mm visual analog scale. Nonstudy analgesic use was also measured. RESULTS: Twenty-five subjects returned the first treatment survey, and 17 returned all 3 surveys. Results were nonsignificant, but guaifenesin trended toward being better than placebo for dysmenorrhea pain and associated constitutional symptoms and caused no worsening of symptoms. Lower abdominal mean pain scores from the first survey decreased 38 mm for guaifenesin versus 7 mm for placebo. By the third survey, only 2 of 8 guaifenesin participants took nonstudy analgesics compared with all 9 placebo subjects. CONCLUSIONS: Guaifenesin may be useful in the treatment of primary dysmenorrhea. A larger study is needed to validate these initial findings.     

Identifying potentially ineffective care in a community hospital

OBJECTIVES: To develop a formula to predict mortality for intensive care unit patients between day 5 in an intensive care unit and 100 days after hospital discharge from a community hospital. DESIGN: Retrospective 1-yr derivation study with validation on a subsequent year's intensive care unit population. SETTING: An 850-bed, not-for-profit community hospital with three adult intensive care units, including medical-surgical, cardiac-medical, and cardiac-surgical units. PATIENTS: The development patient set included 4045 consecutive adult admissions to the intensive care unit between July 1995 and June 1996. The validation sample consisted of 4084 admissions between July 1996 and June 1997. RESULTS: During the first year, 100-day posthospital discharge mortality was predicted by the combination Acute Physiology and Chronic Health Evaluation (APACHE) III predicted mortality on day 5 of >0.92 or the product of day 1 and day 5 APACHE predicted mortality of >0.40, with an increase in the APACHE predicted mortality from day 1 to day 5 of >0.10. Specificity in the development cohort was 0.99, sensitivity was 0.30, and positive predictive value was 0.95. The second-year validation study demonstrated a specificity, sensitivity, and positive predictive value of 0.98, 0.29, and 0.91, respectively, when applying the model to the validation sample. CONCLUSIONS: By using readily available APACHE III data, we were able to identify patients at high risk of dying between intensive care unit day 5 and 100 days after discharge. Although the low sensitivity limits the number of patients for whom death at 100 days is predicted, the high specificity and positive predictive value suggests this information may provide useful information for families and physicians. If these formulas can be validated in diverse institutional settings, decisions regarding short- and long-term outcomes may be improved by using objective survival predictions from two time points.