The removal of acetabular bone in hip resurfacing and cementless total hip replacement: a comparison using the ratio of the size of the acetabular component to the diameter of the native femoral head.

The purpose of this study was to compare the amount of acetabular bone removed during hip resurfacing (HR) and cementless total hip replacement (THR), after controlling for the diameter of the patient's native femoral head. Based on a power analysis, 64 consecutive patients (68 hips) undergoing HR or THR were prospectively enrolled in the study. The following data were recorded intra-operatively: the diameter of the native femoral head, the largest reamer used, the final size of the acetabular component, the size of the prosthetic femoral head and whether a decision was made to increase the size of the acetabular component in order to accommodate a larger prosthetic femoral head. Results were compared using two-sided, independent samples Student's t-tests. A statistically significant difference was seen in the mean ratio of the size of the acetabular component to the diameter of the native femoral head (HR: 1.05 (SD 0.04) versus THR: 1.09 (SD 0.05); p < 0.001) and largest acetabular reamer used to the diameter of the native femoral head (HR: 1.03 (SD 0.04) versus THR: 1.09 (SD 0.05); p < 0.001). The ratios varied minimally when the groups were subdivided by gender, age and obesity. The decision to increase the size of the acetabular component to accommodate a larger femoral head occurred more often in the THR group (27% versus 9%). Despite the emphasis on avoiding damage to the femoral neck during HR, the ratio of the size of the acetabular component to the diameter of the native femoral head was larger in cementless THR than in HR.

Delirium on hospital admission in aged hip fracture patients: prediction of mortality and 2-year functional outcomes.

BACKGROUND: Hip fracture patients are at increased risk of confusion or delirium due to the trauma associated with the injury and the rapid progression to hospitalization and surgery, in addition to the pain and loss of function experienced. Hip fracture patients who develop delirium may require longer hospital stays, are more often discharged to long-term care, and have a generally poor prognosis for returning home or regaining function in activities of daily living (ADL). METHODS: The present study examines the impact of delirium present on hospital admission in a sample of 682 non-demented, aged hip fracture patients residing in the community at the time of their fracture. In-hospital assessments designed to assess both prefracture and postfracture functioning, as well as follow-up interviews at 2, 6, 12, 18, and 24 months postfracture, were obtained from participants. RESULTS: Analyses indicate that baseline or admission delirium is an important prognostic predictor of poor long-term outcomes in persons without known cognitive impairment, after controlling for age, gender, race, comorbidity, and functional status. Delirium at admission (i.e., prior to surgery) was associated with poorer functioning in physical, cognitive, and affective domains at 6 months postfracture and slower rates of recovery. Impairment and delays in recovery may be further exacerbated by increased depressive symptoms in confused patients over time. Delirium on hospital admission was not a significant predictor of mortality after adjustment for confounding factors. CONCLUSIONS: The present findings further emphasize the significance of immediate detection and treatment of delirium in hip fracture patients to ameliorate the short and long-term effects of acute confusion on functional outcomes.

The effect of cytokines on the proliferation and migration of bovine meniscal cells.

We determined the effect of cytokines on the proliferation and migration of cells isolated from the inner-third (white-white), middle-third (red-white), and outer-third (red-red) regions of bovine meniscus. Cells from the outer, or peripheral, region of the meniscus exhibited higher DNA synthesis in the presence of 10% serum compared with cells from the inner or central regions. Recombinant human platelet-derived growth factor-AB, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated DNA synthesis of all meniscal cells in a dose-dependent manner, with a two- to threefold maximal stimulation at 10 ng/ml. Cell migration was also stimulated by addition of cytokines. Platelet-derived growth factor and hepatocyte growth factor caused an increase in the migration of cells derived from all three zones, while interleukin-1 selectively stimulated the migration of outer-zone meniscal cells. Epidermal growth factor was much less effective and stimulated the migration of cells in the inner and outer zones by 40% to 50%, while bone morphogenic protein-2 and insulin-like growth factor-1 stimulated the migration of meniscal cells from the middle zone by 40% to 50%. The identification of cytokines that stimulate both the growth and migration of meniscal cells may provide new tools for modulation of meniscal healing.

Everyday problem solving among individuals with Alzheimer's disease.

Loss of functioning on complex tasks of daily living is an early indicator of dementia. The performance of 65 older adults with mild to moderate levels of Alzheimer's disease was examined on the Everyday Problems Test for the Cognitively Challenged Elderly (EPCCE), self-report inventories of functional performance, and a broad battery of clinical and neuropsychological measures. The EPCCE was designed to assess older adults on a set of complex tasks of daily living that involved not only global cognitive processes, but also higher-order executive functions. Participants solved an average of 45% of EPCCE tasks with significant differences in scores by disease severity. Performance was significantly related to global cognitive functioning and disease severity, and in particular to executive functions. Significant additional variance was accounted for by these executive functions beyond the variance accounted for by global cognitive measures.

Modulation of tendon healing by nitric oxide.

Nitric oxide (NO) is a small, diffusible free radical that is generated from L-arginine by a family of enzymes, collectively termed the nitric oxide synthases. We investigated the role of NO in tendon healing. NO synthase activity and immunoreactivity was absent in un-injured rat Achilles tendon. After surgical division there was a five-fold increase in NO synthase activity and immunoreactivity within the healing tendon at day 7, with a return to near baseline levels at day 14. Inhibition of NO synthase activity with oral administration of N omega-nitro-L-arginine methyl ester (L-NAME) resulted in a significant reduction in cross-sectional area (30% at day 7, p < 0.01, 50% at day 15, p < 0.001) and failure load (24% at day 7, p < 0.01) of the healing Achilles tendon constructs. Rats fed the same regimen of the enantiomer of L-NAME, (D-NAME) had normal tendon healing. These results indicate that nitric oxide synthase is induced during tendon healing and inhibition of nitric oxide synthase inhibits this tendon healing.

C31G, a new agent for oral use with potent antimicrobial and antiadherence properties.

C31G, an equimolar mixture of alkyl dimethyl glycine and alkyl dimethyl amine oxide, was evaluated for antimicrobial and antiadherence properties. The efficacy of C31G, its two components, and several commercial mouth rinses was determined in assays measuring inhibition of glycolysis, inhibition of bacterial adherence, and MICs. Inhibition of glycolysis was determined by using a saliva sediment model, with glycolytic activity expressed as the change in pH relative to that of a control. Adherence studies were undertaken with Streptococcus sobrinus 6715 to measure inhibition of adherence to nichrome wires. MICs were determined against selected microorganisms by standard methods. C31G demonstrated broad-spectrum antimicrobial properties, with activity against both gram-positive and gram-negative organisms and Candida albicans, a yeast. C31G inhibited both glycolysis by salivary bacteria and adherence of Streptococcus strains to wire mesh. C31G was more effective in the assays conducted than any commercial formulation tested and was as effective as chlorhexidine. A synergistic effect was demonstrated between the individual components of C31G, and no loss of activity was noted when it was formulated into a mouth rinse vehicle.

Comparison of effects of two dosage regimens of phenylpropanolamine on blood pressure and plasma levels in normal subjects under steady-state conditions.

Plasma levels and blood pressure responses to two dosage regimens of phenylpropanolamine (PPA)-25-mg, immediate-release tablets three times per day and a 75-mg, controlled-release capsule once per day--were compared in 14 normal subjects. To obtain steady-state conditions, subjects were given the test materials for four-day periods, and blood pressure and plasma PPA levels were measured on day 4. The dosage forms were equally bioavailable, based on a 95-percent confidence coefficient, and neither produced hypertensive effects. The highest diastolic pressure was 96 mm Hg three hours after a 25-mg dose. Mean PPA plasma levels showed no correlation with mean blood pressure readings at any point during a 12-hour test period. These data show that, in these subjects, a daily dosage of PPA 75 mg, either in divided doses of 25 mg each or in a dependable controlled-release formula, produces no indication of pressor effects.

In vitro method for evaluation of spermicides by hemolytic potency.

Nonoxynol-9 immobilizes sperm and hemolyzes erythrocytes at analogous concentrations; therefore, erythrocytes may be utilized for predicting in vitro spermicidal potency. Since erythrocytes (human or rabbit) are usually more readily available in larger quantities than are spermatozoa, this method permits extensive in vitro testing of different formulations of vaginal spermicides.

Anticalculus and antiplaque activity of 8-hydroxyquinoline sulfate.

The effect of 8-hydroxyquinoline sulfate on the formation of artificial calculi, rat calculus, and dog plaque plus its ability to remove dog plaque were studied. Several chemically related agents were also evaluated for their anticalculus effects. The most effective anticalculus agent was 8-hydroxyquinoline sulfate. At concentrations of 4 or 5%, swabbed over molar teeth, it was essentially equally effective in retarding the formation of rat calculus. Significant (1% level) reduction occurred with concentration as low as 3% in rats. When used so as to mimic mouthrinse use, 4% 8-hydroxyquinoline sulfate also significantly (5% level) reduced formation of calculus in rats. All rats showed normal behavioral and weight-gain patterns. Visual evaluation of oral tissues in the swabbing tests plus visual and histopathological evaluation of oral tissues in the mouthrinse procedure showed 8-hydroxyquinoline sulfate had no irritating or toxic effects. In dogs, the teeth treated with 4% 8-hydroxyquinoline sulfate nine times during a five-day period had 93.7 to 98.4% less buccal plaque than vehicle-treated teeth. The antiplaque effect was considerable in both canines and fourth premolars. In older dogs, teeth treated with 4% 8-hydroxyquinoline sulfate 15 times during a ten-day period had 33 to 46.1% less plaque than when treated with the vehicle. The effect was considerable on canines but slight on fourth premolars. In older dogs after 24 treatments during a 15-day period, 4% 8-hydroxyquinoline sulfate removed 25 to 57.5% of established plaque whereas the vehicle removed 2.5 to 22.5%. Again, 8-hydroxyquinoline sulfate was more effective on canine buccal plaque. These results show that 8-hydroxyquinoline sulfate is an effective anticalculus and antiplaque agent that is nontoxic to animal oral tissue. The results also indicate that the dog is a suitable animal model for the evaluation of antiplaque agents.