Femoral expansion in total hip arthroplasty

With increasing age, the femoral medullary canal expands and cortical thickness decreases. Examination of the radiographs of 22 hips that had undergone total hip arthroplasty revealed that at a mean interval of 11.5 years the medullary canal had expanded at an average rate of +0.328 mm/year (P less than .0001). There was a concomitant mean cortical atrophy of -0.155 mm/year (P = .0006). These rates of expansion are similar to those observed in natural aging. The presence of a femoral prosthesis is associated with temporal changes in femoral geometry similar in magnitude to those occurring in the natural femur. Because of the fundamental changes in load transmission caused by the presence of a femoral prosthesis, these geometric changes may be in part secondary to the bone's adaptation to altered load transmission, as well as to natural aging phenomena. Recognition of the pattern of natural femoral expansion suggests certain strategies for design criteria that seek to maximize fit.

Carbonic anhydrase inhibition and cell volume regulation in Necturus gallbladder

Gallbladder epithelial cells transport salt and water isotonically as the renal proximal tubule. The cells also have the property of regulating their cell volume in response to osmotic stress (Fisher et al. 1981, Persson & Spring 1982, Fisher & Spring 1984, Foskett & Spring 1985). The volume-regulating phenomenon is the result of a balance between cell uptake of salt and water at the luminal membrane and exit at the basolateral membrane. Different properties regarding volume regulatory increase and decrease have been found (Eriksson & Spring 1982 and Larson & Spring 1983). The present study links fluid transport and volume regulatory increase of the cell. First we concluded from histological techniques that carbonic anhydrase is present in the cell membrane or in the vicinity of the epithelial cells. Then we measured a decreased net fluid transport in the presence of increasing concentrations of the carbonic anhydrase inhibitor acetazolamide. We showed that the volume regulatory increase is substantially slowed down and that the steady-state volume of the cells changed when carbonic anhydrase was inhibited. Our conclusion is that the rate of CO2 hydration was a limiting step, at carbonic anhydrase inhibition, in both the net transfer of salt and water and also in the ability of the cells to efficiently regulate their volume.

Auranofin therapy and quality of life in patients with rheumatoid arthritis. Results of a multicenter trial

In a six-month, randomized, double-blind study at 14 centers, auranofin (3 mg twice daily) was compared with placebo in the treatment of patients with classic or definite rheumatoid arthritis. All patients had unremitting disease for at least the previous six months and at least three months of therapy with nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs, oral steroids, and analgesics were allowed throughout the trial. Efficacy was analyzed in 154 patients who received auranofin and 149 who received placebo. To reflect an expanded view of outcome assessment, the measures used included some 20 nontraditional measures of functional performance, pain, global impression, and utility (worth or value) in addition to five standard clinical measures of rheumatoid synovitis (e.g., number of tender joints). The nontraditional measures were mainly in the form of structured questionnaires administered by trained interviewers. To minimize the statistical problem of multiple comparisons, most of the measures were grouped into four composites--clinical (standard measures), functional, global, and pain--and the treatment effect for each composite was tested at the 0.0125 level of significance. Auranofin was superior to placebo in the clinical (p = 0.003), functional (p = 0.001), and global (p = 0.007) composites and trended similarly in the pain composite (p = 0.021). Individual measures within the composites consistently favored auranofin. Other measures, not part of the composites, also favored auranofin, including a patient utility measure designed for this study, the PUMS (p = 0.002). Results confirm the hypothesis that the favorable effect of auranofin on clinical synovitis is accompanied by improvements across a range of outcomes relevant to the patient's quality of life.

Sex ratio and sibship size in juvenile rheumatoid arthritis kindreds

In a study of sibship size and sex ratio in juvenile rheumatoid arthritis, the anticipated sex ratios, including a marked female predominance in early onset pauciarticular disease and in polyarticular disease, were found. The size of the sibship showed a progressive increase with increasing age of the proband at onset of disease. In addition, the sex ratios of the sibs deviated from expected, among families where the proband's disease was characterized as either early onset pauciarticular or polyarticular in its presentation.

HLA gene frequencies in children and adults with systemic onset juvenile rheumatoid arthritis

The HLA genetic region was studied in 51 patients with systemic onset juvenile rheumatoid arthritis: 35 with childhood onset and 16 with adult onset (adult Still's disease). HLA genotypes were established by including family members, 261 of whom were also typed in the study. The most marked difference between patients and controls involved the HLA-DR4 gene, which occurred with a frequency of 0.348 in the childhood onset patients and 0.170 in the controls (chi 2 = 8.97, P = 0.0028, adjusted P = 0.017). In contrast, the adult onset patients showed a marginal increase in HLA-DR7, but were similar to controls with respect to HLA-DR4. HLA-Bw35 was increased in children with systemic onset disease, in accordance with earlier findings. The results suggest that patients with systemic onset juvenile rheumatoid arthritis have complex HLA associations which are different in childhood onset and adult onset disease.

Volume regulation by Necturus gallbladder: basolateral KCl exit

Swelling of the epithelial cells of Necturus gallbladder caused by an 18% reduction in the osmolality of the mucosal bath is followed by rapid volume readjustment. This volume regulatory decrease requires Cl and is sensitive to the K and Cl gradients across the basolateral cell membrane. Volume regulatory decrease is not inhibited by amiloride, SITS, ouabain or bicarbonate removal. The process is blocked by bumetanide in the serosal bath. Measurement of the intracellular activities of K and Cl and the rate of volume regulation under five different experimental conditions showed that KCl exited from the cell across the basolateral membrane with a stoichiometry of 3 K to 2 Cl. This KCl exit process appears to be transiently activated following the reduction in osmolality of the mucosal perfusate.

Respiratory muscle training with the incentive spirometer resistive breathing device

Utilizing the conceptual scheme of Kim, this study focused on the effect of inspiratory muscle training on the strength of the respiratory muscles, exercise performance, clinical manifestations, and activities of daily living. Unlike previous studies, inspiratory muscle training was performed by the use of an ISRBD that gave alinear inspiratory resistance of 50 cm H2O/L/sec at 1 L/sec flow. Subjects used an ISRBD twice a day for 15 minutes each day for 4 weeks. Strength of respiratory muscles as measured by PImax and sputum expectoration improved significantly (P less than 0.05) but there was no significant change in exercise performance (12-minute walk distance), other clinical signs and symptoms, or activities of daily living. Visual feedback given by the bellows of the ISRBD that inflated and deflated with inspiration and expiration apparently served as a positive reinforcer and motivator for most subjects. Daily logs of clinical signs and symptoms and activities of daily living, along with weekly telephone conferences with each subject, provided comprehensive data and may have contributed to the high compliance rate (98%) in this study.

Costs and outcomes in rheumatoid arthritis and osteoarthritis

A prospective descriptive study was done on the direct and indirect costs to ambulatory patients with rheumatoid arthritis and osteoarthritis, stratified at study entry by level of function. Measures of health status over a 1-year period were taken. On a yearly basis, in 1979 dollars, patients spent an average of $147 for arthritis medications, aids, and devices, and $207 for outpatient visits. A small number were hospitalized and incurred an average charge of $245, and an additional $84 for physician fees. In addition to direct monetary costs, patients averaged 6.8 days of restricted activity costs, patients averaged 6.8 days of restricted activity per month, in some cases so severe as to confine patients to bed for an average of 1.3 days per month. Among students and working patients, 2.5 work-days per month were lost due to arthritis, and 30% reported that they were unemployed or retired because of impaired health. Functional capacity and specific diagnosis on entry to the study were the most important determinants of arthritis-related expenditures. Both direct and indirect costs varied considerably from the observed average. Twenty percent of patients incurred no costs for arthritis-related purchases, 42+ had no costs for outpatient visits, and 93% had no inpatient costs. Yet for some patients, the financial burden was very high.

Renal interstitial volume of the rat kidney

The intravascular plasma volume and the interstitial volume of the rat kidney were determined by an indicator dilution method with a bolus injection of 125-I-labelled human serum albumin and 51-Cr-EDTA into the renal artery and subsequent recording of the indicator-dilution curves in the venous effluent, sampled at intervals of 0.33 s. The curves allowed determination of both the mean transit time of the two indicators and total renal plasma flow. The volumes of distribution were obtained by multiplying these two factors. Under control conditions the plasma volume was 93.0 +/- 11.2 microliters/100 g rat (mean +/- SE), which is 17.9% of the total kidney volume. The interstitial volume was 68.3 +/- 8.6 microliters/100 g, corresponding to 13.1% of the total kidney volume. During expansion with 0.15 M NaCl, 10% of body weight, the plasma and interstitial volumes were not significantly increased. The values for the two volumes were 101.6 +/- 9.7 and 72.8 +/- 6.8 microliters/100 g, respectively. The kidney weight showed, in contrast a clear increase from 539 to 670 mg/100 g, reflecting the expansion of the proximal and distal tubules due to the increased glomerular filtration rate. It is concluded that although the saline load produced a rise in the renal interstitial pressure, the expected expansion of the interstitium became small, due to the parallel expansion of both the vascular and tubular systems which compress the renal interstitium.

The psychosocial impact of systemic lupus erythematosus and rheumatoid arthritis

Seventy-six ambulatory patients with systemic lupus erythematosus and a comparison group of 23 ambulatory patients with rheumatoid arthritis were given a structured interview and standard psychological tests, including the Minnesota Multiphasic Personality Inventory, to determine the psychosocial impact of the illness. Both groups had significantly elevated scores on 3 Minnesota Multiphasic Personality Inventory scales: Hypochondriasis, Depression, and Hysteria. Psychological difficulties are an integral part of systemic lupus erythematosus and are as common as most other manifestations. The implications for clinical practice are discussed.

Bumetanide inhibition of NaCl transport by Necturus gallbladder

Salt transport by the Necturus gallbladder epithelium is the result of the coupled entry of NaCl into the cells across the apical membrane and the active transport of Na out of the cells across the basolateral membrane. The NaCl entry step was studied by measuring the rate of cell volume increase accompanying ouabain inhibition of the Na--K-ATPase in the basolateral membrane. When bumetanide, a diuretic analog of furosemide, was added to the mucosal bathing solution it reversibly blocked the entry of NaCl into the cells and abolished fluid transport. A dose-response relationship showed half-maximal inhibition of NaCl entry at a bumetanide concentration of 10(-9) M; complete inhibition of coupled NaCl movement occurred with as little as 10(-7) M bumetanide. Partial substitution of Na or Cl in the mucosal solution failed to demonstrate competition between bumetanide and either of the ions. The drug was also effective in blocking NaCl entry in the absence of ouabain; addition of the diuretic to the mucosal bathing solution resulted in prompt cell shrinkage and a decrease in intracellular NaCl. Cell volume decrease followed bumetanide addition to the mucosal bath because NaCl entry was blocked but active Na transport continued for several minutes until the intracellular Na transport pool was depleted.

The influence of surgery and radiation therapy on patients with brain metastases

The place for operation and for radiation therapy in the management of brain metastases is reviewed from the experience of 1895 patients treated in two studies of the Radiation Therapy Oncology Group. Operative removal may be of benefit to patients with solitary peripheral lesions in non-critical brain locations. Operation is also appropriate when the diagnosis is in doubt. Radiation therapy with appropriate steroid management is of benefit to patients with multiple metastases or where operative intervention is not reasonable. Short course low-dose treatment has been as beneficial as more aggressive prolonged radiation therapy.

Hydraulic permeability of the peritubular and glomerular capillary membranes in the rat kidney

The hydraulic conductivity of the peritubular capillary membrane was calculated from 1) single nephron fluid reabsorption and 2) net driving force, i.e. from hydrostatic and colloid osmotic pressures in renal interstitium and peritubular capillary blood, as determined by a micropuncture technique and with use of a computer-based model. Under control conditions the net driving force was estimated to be 15.4 mmHg and the hydraulic conductivity 1.04 nl/(min . mmHg) per 100 g rat. During extracellular volume expansion with 0.15 M saline, 4% and 10% of body weight, the net driving force decreased to 12.5 mmHg and 6.4 mmHg, respectively, whereas the conductivity increased to 1.85 and 3.14 nl/(min . mmHg) per 100 g rat. The reduction in net driving force was compensated by an increased hydraulic conductivity. In the glomeruli the net driving force for filtration increased from 14.2 mmHg under control conditions to 21.2 mmHg and 25.3 mmHg during saline expansion 4% and 10%, whereas the corresponding hydraulic conductivity de increased from 1.13 nl/(min . mmHg) per 100 g rat to 1.03 and 0.80 nl/(min . mmHg) per 100 g rat during the two expansions. During saline expansion the water permeability of the glomerular capillaries is decreased while that of the peritubular capillaries is increased. These changes in the water permeability will lead to retarded excretion of the excess fluid.

A study of the use of the probability-of-being-in-response function as a summary of tumor response data

The probability-of-being-in-response function (PBRF), proposed by Temkin (1978, Biometrics 34, 571-588) as a vehicle for analyzing transient response data, is examined using the simplified parametric model in which each of the failure processes is assumed to be exponential. Properties of the PBRF under these assumptions are discussed. It is demonstrated that the PBRF is a very complete summary of the data and has attractive properties for its intended use as a visual display. The model is extended to incorporate covariates, and it is demonstrated that the desired properties can be generalized under specific conditions for the covariates.

Equivalence of radiation schedules for the palliative treatment of brain metastases in patients with favorable prognosis

Five whole-brain irradiation schedules ranging from 2000 rad in one week to 4000 rad in four weeks were evaluated in 1830 patients with cerebral metastases treated in two randomized studies by the Radiation Therapy Oncology Group. The duration of palliative effectiveness among those patients with favorable survival prognosis was investigated. Favorable subgroups were identified consisting of 123 ambulatory breast cancer patients with no soft tissue metastases, 373 ambulatory lung cancer patients with primary absent or no extracerebral metastases, and 65 ambulatory patients with other primaries and no extracerebral metastases. This group of 561 patients had a median survival of 28 weeks compared with 11 weeks for the remaining patients. Analyses of neurologic function control rates failed to show a significant benefit of higher doses. No advantage was demonstrated for treating brain metastases patients with favorable prognoses with more than one week of whole-brain irradiation.

Functional characteristics of the renal interstitium

The renal interstitial space analyzed as "inulin space" comprises about 13% in the rat. The Starling forces of this compartment are governed by the balance between tubular and capillary fluid transport and also by the leakage of plasma proteins from the blood side. Protein transport will occur in a large-pore system in the peritubular capillary membrane. During control antidiuresis, the interstitial hydrostatic pressure is 2-4 mmHg. The colloid osmotic pressure shows a larger variability but is generally about 5 mmHg. During conditions of depressed capillary reabsorption but unchanged tubular reabsorption, as in saline expansion, the interstitial hydrostatic pressure rises 3-4 times, whereas the colloid osmotic pressure will show a steep fall resulting from the increased fluid entry and unchanged protein transport. The interstitial volume increases only slightly, since it is compressed by the expanding tubules. The influence of interstitial physical forces on tubular transport remains unclear, mainly due to the inaccessibility of the lateral interspaces to direct measurement of relevant parameters.

Ovarian failure in long-term survivors of childhood malignancy

The frequency and causes of ovarian failure among 182 long-term survivors of childhood cancer were examined. Twenty-two patients (12%) had ovarian failure. Ovarian failure was found in 17 of 25 patients (68%) who had both ovaries within abdominal radiotherapy fields, in five of 35 patients (14%) whose ovaries were at the edge of the treatment field, and in none of 122 patients with one or both ovaries outside of an abdominal treatment field (p < 10(-4)). The odds for ovarian failure in patients with both ovaries in the field are 19.7 higher than those for other irradiated patients (95% confidence interval, 5.3 to 72.8). Covariate and multivariate analyses of tumor type, age at diagnosis, duration of follow-up, abdominal tumor surgery, abdominal radiotherapy, number of chemotherapeutic agents administered, and cumulative doses of several drugs revealed that the location of the ovaries relative to radiation treatment fields was the only risk factor for subsequent ovarian failure.

Influence of renal nerve activity on arteriolar resistance, ultrafiltration dynamics and fluid reabsorption

In anaesthetized 300 g rats, the influence of sympathetic nerve activity on the renal hemodynamics, glomerular filtration and fluid reabsorption was studied with direct stimulation at frequencies of 2 Hz and 5 Hz. The single nephron plasma flow at control conditions was 164 nl/min decreasing to 138 nl/min during 2 Hz and 68 nl/min during 5 Hz, reaching complete glomerular ischemia at about 10 Hz. At 2 Hz, the pressure drop over the two arterioles remained essentially unchanged, indicating an equal response to sympathetic discharge. At higher frequencies the afferent tone showed a more marked increase. The glomerular ultrafiltration decreased in parallel to the blood flow. The filtration fraction remained thereby constant at about 0.33. The fractional proximal fluid reabsorption up to the puncture site in early distal tubules showed a clear increase; the Tf/P-Inulin increasing from 6.0 to 7.1 and 7.2 for 2 Hz and 5 Hz, respectively. The absolute reabsorption decreased, however, and indeed not far from the decrement in glomerular filtration. It is concluded that sympathetic nerve activity acts in the direction of fluid conservation, by reducing the glomerular filtration and increasing the fractional reabsorption. The hemodynamic effects will play the dominant role even at 2 Hz stimulation.