Quantitative gait analysis after bilateral total knee arthroplasty with two different systems within each subject

The functional behavior of two kinematically different knee arthroplasty systems within each subject was studied by gait analysis (three-dimensional kinematics, kinetics, dynamic electromyography) in five elderly patients, 2 to 5 years after bilateral surgery. Clinical results were good, yet gait velocity was reduced (range, 0.57-1.1 m/s), with a shortened stride length and a decreased duration of single-limb stance in all subjects. Force plate recordings revealed an undynamic gait with slow loading, reduced modulation of the vertical forces, and poor fore/aft shears. Sagittal plane knee motion during gait was reduced in all subjects, with trunk and pelvic compensation patterns for foot clearance. Muscle activity around the knee was prolonged bilaterally, with activity modulation related to the motion pattern. Although the stride parameters were quite symmetric, there was a marked asymmetry of the motion pattern, with a side-to-side difference of peak knee flexion during stance and swing phase of up to 15 degrees. This finding, however, was not clearly related to the type of prosthesis. Even within one subject, significant side-to-side variability may persist, which leads to asymmetry of the motion pattern, unrelated to the kinematic design of the implant. Other factors, such as the patella-extensor mechanism, ligament balancing, leg-length discrepancy, proprioception, continuation of a preoperative habit, or a contralateral influence, may explain part of the asymmetry seen in these subjects.     

Ultrastructural criteria that prove the similarities between amphibian and human tumors

The relationship between selected foods and nutrients and breast cancer risk was investigated in strata of age and menopausal status using data from a case-control study on breast cancer conducted between June 1991 and April 1994 in six Italian areas. Cases were 2,569 women with histologically confirmed incident breast cancer admitted to the major teaching and general hospitals of the study areas; controls were 2,588 women with no history of cancer admitted to hospitals in the same catchment area as cases for acute, nonneoplastic, nongynecological conditions unrelated to hormonal or digestive tract diseases or to long-term modifications of diet. Dietary habits were investigated using a validated food frequency questionnaire, including 78 foods or food groups. Among food groups, bread was directly and significantly related to breast cancer risk in older women and, consequently, in postmenopause, whereas the protection conferred by fish consumption was stronger in postmenopause and that exerted by raw vegetables was stronger in premenopause. Among nutrients, unsaturated fatty acids were inversely related to breast cancer risk, the association being stronger in postmenopausal and elderly women. The pattern was similar for total fats. For starch, available carbohydrates, and total proteins, no heterogeneity emerged across strata of age and menopausal status. Among micronutrients, protection diminished with increasing age for beta-carotene and calcium, whereas no heterogeneity emerged for vitamin E. Thus this age-specific analysis of the largest investigation to date on diet and breast cancer did not show any consistent pattern of breast cancer risk in relation to selected dietary factors across strata of age and menopausal status.     

Long-term outcome of a prospective randomized trial of conversion from cyclosporine to azathioprine treatment one year after renal transplantation

BACKGROUND: Since the introduction of cyclosporine (CsA), 1-year renal allograft survival has improved, but concern persists about the long-term adverse effects of CsA, especially with respect to renal function and blood pressure. This randomized controlled trial was set up to establish whether withdrawal of CsA would alter long-term outcome. METHODS: Adult patients who, at 1 year after renal transplantation, had a stable serum creatinine of less than 300 micromol/L and who had not had acute rejection within the last 6 months were eligible for entry. Patients were randomized either to continue on CsA (n=114) or to stop CsA and start azathioprine (Aza, n=102). All patients remained on prednisolone. Median follow-up was 93 months after transplantation (range: 52-133 months). RESULTS: There was no significant difference in actuarial 10-year patient or graft survival (Kaplan-Meier), despite an increased incidence of acute rejection within the first few months after conversion. Median serum creatinine was lower in the Aza group (Aza: 119 micromol/L; CsA. 153 micromol/L at 5 years after randomization, P=0.0002). The requirement for antihypertensive treatment was also reduced after conversion to Aza; 75% of patients required antihypertensive treatment at the start of the study, decreasing to 55% from 1 year after randomization in the Aza group and increasing to >80% in the CsA group (55% (Aza) and 84% (CsA) at 5 years after randomization, P<0.005). CONCLUSIONS: Conversion from CsA to Aza at 1 year after renal transplantation results in improvement in both blood pressure control and renal allograft function, and is not associated with significant adverse effects on long-term patient or graft survival.     

Glycopeptide antibiotic resistance genes in glycopeptide-producing organisms

The mechanism of high-level resistance to vancomycin in enterococci consists of the synthesis of peptidoglycan terminating in D-alanyl-D-lactate instead of the usual D-alanyl-D-alanine. This alternate cell wall biosynthesis pathway is ensured by the collective actions of three enzymes: VanH, VanA, and VanX. The origin of this resistance mechanism is unknown. We have cloned three genes encoding homologs of VanH, VanA, and VanX from two organisms which produce glycopeptide antibiotics: the A47934 producer Streptomyces toyocaensis NRRL 15009 and the vancomycin producer Amycolatopsis orientalis C329.2. The predicted amino acid sequences are highly similar to those found in VRE: 54 to 61% identity for VanH, 59 to 63% identity for VanA, and 61 to 64% identity for VanX. Furthermore, the orientations of the genes, vanH, vanA, and vanX, are identical to the orientations found in vancomycin-resistant enterococci. Southern analysis of total DNA from other glycopeptide-producing organisms, A. orientalis 18098 (chloro-eremomycin producer), A. orientalis subsp. lurida (ristocetin producer), and Amycolatopsis coloradensis subsp. labeda (teicoplanin and avoparcin producer), with a probe derived from the vanH, vanA, and vanX cluster from A. orientalis C329.2 revealed cross-hybridizing DNA in all strains. In addition, the vanH, vanA, vanX cluster was amplified from all glycopeptide-producing organisms by PCR with degenerate primers complementary to conserved regions in VanH and VanX. Thus, this gene sequence is common to all glycopeptide producers tested. These results suggest that glycopeptide-producing organisms may have been the source of resistance genes in vancomycin-resistant enterococci.     

Interaction between a murine myeloma cell line and bone marrow stromal cells

Intravenous transplantation of an in vitro maintained murine myeloma cell line, 5T33, results in progressive growth in the bone marrow of C57Bl/KaLwRiJ mice. Concurrent with the growth of the tumor in vivo, the bone marrow stromal cells are inhibited, as assayed by their ability to form stromal cell foci and long-term monolayers in vitro. Inhibition of normal mouse marrow stromal cell growth also occurs when 5T33 cells are added to the marrow cells in vitro, and contact between the marrow and 5T33 cells is not necessary to achieve inhibition, indicating secretion of one or more diffusible inhibitory factors.