Proven and nonproven facts in knee arthroplasty

Summary The great number of knee-replacement systems makes a comparative study difficult. Even more confusing are the different criteria used for the evaluation of the results. After a critical review of what can be taken as proven facts, our own experience with the semiconstrained GSB-III knee prosthesis is critically analyzed. The survivorship method is used, presenting the cumulative success rate and analyzing the reasons for the failure rates. We feel that all authors presenting results of knee arthroplasty should adopt this method, using the same or at least comparable evaluation sheets (for instance, that of ERASS). Moreover, more attention should be given to bone dynamics in a prospective study using modern technology (CT densitometry). This will help to detect possible factors responsible for the failure of knee arthroplasty and possibly to prevent failure with medication.

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Zusammenfassung Die große Zahl verschiedener Kniegelenks-Systeme im prothetischen Ersatz erschwert vergleichendes Studium. Zusätzliche Schwierigkeiten erwachsen aus der Verwendung verschiedener Kriterien bei der Auswertung der Ergebnisse. Wir selbst haben zur Erfahrung mit der GSB-III Knie-Endoprothese kritisch analysiert, nachdem wir versucht haben nur eindeutige Fakten miteinzubeziehen. Wir verwendeten die sogenannte survivorship Methode (Überlebenskurven) und untersuchten die cumulative Erfolgsrate und die Gründe für die Fehlschläge. Wir vertreten die Auffassung, daß alle Autoren, die Ergebnisse über Knie-Arthroplastiken vorstellen, diese Methode verwenden sollten, wenn immer möglich unter Gebrauch desselben oder mindestens vergleichbarer Erhebungsbogen (z. B.

     

Management of patients supported on the Hemopump cardiac assist system

The Hemopump Cardiac Assist System is a relatively new intraarterial, axial-flow circulatory assist device that offers temporary left ventricular support to patients in refractory cardiogenic shock, without requiring major surgery for insertion. Use of the Hemopump is associated with a low complication rate. Device-related morbidity is extremely rare. Because the Hemopump is safe for use in community hospitals, the number of patients supported by this device is expected to increase. In this report, we present general guidelines for the care of patients supported by the Hemopump. We describe techniques for the management of afterload reduction, supravalvular dislodgement, device malfunction, ventricular ectopy, intracardiac shunting, and inflow cannula obstruction.     

Soman intoxication-induced changes in serum acute phase protein levels,corticosterone concentration and immunosuppressive potency of the serum

We have studied the effect of soman intoxication on serum acute phase reactants (APR) levels, and the relationship of the APR and corticosterone concentrations and the immunosuppressive activity of the serum. One day after the injection of 1.8 LD₅₀ soman the concentrations of ₂-macroglobulin (₂-MG) and ₁-acid glycoprotein (AGP) in the serum of antidote protected rats increased 4- and 7-fold, respectively, whereas those of hemopexin (Hx), haptoglobin (Hp) and cysteine protease inhibitor (CPI) were two to three times higher than in the controls. A similar magnitude of increase of serum acute phase reactants levels was observed when 0.3 LD₅₀ soman was administered at 24-h intervals over the 5-day period. The relationship of changes in the APR concentration, corticosterone level and immunosuppressive activity of the serum was also comparable to that observed in the acute phase response to tissue injury.     

Comparison of genomic damage caused by 5-nitrofurantoin in young and adult mice using the in vivo micronucleus assay

The antibiotic 5-nitrofurantoin (5-NF) has been used widely for the treatment of urosepsis in children during the last 20 years. Recent experimentation suggests the need for reevaluating its genotoxic potential. Because of possible differences in the metabolism and clearance of 5-NF in young and adult animals, we conducted a study to determine whether micronuclei caused by 5-NF were age-related. The in vivo micronucleus (MN) assay was performed on 3- and 8-week-old mice given single intraperitoneal injections of 5, 10, and 50 mg/kg 5-NF. Blood samples from the tail vein were taken before injection (baseline) and at 48, 96, 168, and 336 hr (2 weeks) after the treatment. One thousand reticulocytes were analyzed for micronuclei from each animal. Compared to similar baseline values for young and adult mice, 5-NF caused a significant increase in MN frequency in both age groups. The mean MN frequency in the young animals was higher than in the adult animals for each dose and sampling time. MN frequencies remained significantly elevated in young animals even 2 weeks after exposure to 5-NF. The results of the study confirm the genotoxic potential of 5-NF in young and adult animals, and indicate that young animals are more sensitive to the genotoxic effects of 5-NF than adult mice and that the response in young mice persists for a significantly longer time. These findings may be related to poorly developed mechanisms of xenobiotic detoxification and renal elimination in young animals.     

Identification of GRASP-1 as a novel 97 kDa autoantigen localized to endosomes

We have identified an autoantigen that is recognized by antibodies from an 18-year-old female with a history of recurrent infections who later in her clinical course developed Raynaud's phenomenon and telangiectasias. By indirect immunofluorescence (IIF), the index serum produced a unique cytoplasmic discrete speckled (CDS) staining pattern that partially colocalized with early endosome antigen 1 (EEA1) but not Golgi complex or other cytoplasmic organelles in HEp-2 cells. When HEp-2 cells were treated with 0.1 N HCl, the cytoplasmic speckled staining of the index serum was markedly decreased, suggesting that the reactive antigen was soluble. Western blot analysis showed a reactive approximately 97 kDa protein in a saline soluble protein preparation from HeLa cells. Mass spectrometric analysis of the excised 97 kDa band that was immunoprecipitated from HeLa cell extracts identified GRASP-1 as a possible target. The index serum and anti-GRASP-1 antibodies colocalized to structures in the cytoplasm of HEp-2 cells. Synthetic peptides representing the full-length GRASP-1 protein were used to identify reactive epitopes. Like many other cytoplasmic autoantigens, GRASP-1 has numerous coiled-coil domains throughout the protein with the exception of short segments at the amino and carboxyl terminus.     

Competitive reactions of L-methionine and 5'-GMP towards platinum (II) complexes

The complex-formation reactions of the platinum(II) complexes, [Pt(dien)H2O]2+, [PtCl(dien)]+ and [PtBr(dien)]+ (dien is diethylenetriamine) with some biologically relevant ligands such as inosine (INO), inosine-5'-monophosphate (5'-IMP), guanosine-5'-monophosphate (5'-GMP), glutathione (GSH) and L-methionine (S-meth), were studied by UV-Vis (UV-Visible) spectrophotometry and 1H NMR spectroscopy. Reactions of the [PtCl(dien)]+ with L-methionine were studied in the presence and absence of 5'-GMP. The rate constants clearly showed a kinetic preference toward L-methionine. However, competitive reactions of [PtCl(dien)]+ with L-methionine and 5'-GMP demonstrated initially rapid formation of [Pt(dien)(S-meth)]2+ followed by displacement of L-methionine by 5'-GMP. In the later stages the concentration of [Pt(dien)(N7-GMP )]2+ is predominant. The results are analyzed in reference to the anti-tumour activity of Pt(II) complexes.     

ACTH-producing cells of 21-day-old rat fetuses after maternal dexamethasone exposure

Adrenocorticotrophic hormone (ACTH) is essential for developmental maturation of numerous organ systems during the fetal period and for adaptation to environmental challenges. Immunocytochemical and stereological methods were used in the present study to examine the effects of dexamethasone (Dx) administration during pregnancy on fetal rat pituitary ACTH-producing cells. Doses of 0.5, 0.5 and 1.0 mg Dx/kg body weight/day were given to the dams on 3 consecutive days starting on day 16 of gestation. Morphometric analysis of the ACTH-producing cells of fetuses at 21 days of gestation revealed significant inhibition by 24% and 27%, respectively, of cell volume and cell number after maternal Dx administration, whereas the volume of cell nuclei and volume density of ACTH-stained cells were insignificantly decreased. Immunocytochemical analysis showed reduced numbers, sizes and immunopositivity of ACTH cells of 21-day-old fetuses from Dx-treated dams as compared with the control group. Maternal Dx treatment in the period of intense differentiation of the hypothalamo-hypophyseal-adrenal system had an inhibitory effect on fetal function and proliferative activity of ACTH-producing cells at 21 days of gestation. Thus, inhibition of activity of fetal ACTH-producing cells may lead to adrenal suppression, modified activity of the hypothalamo-pituitary-adrenal axis and reduced body weight possibly causing lasting functional abnormalities.     

The effect of ventilation on spectral analysis of heart rate and blood pressure variability during exercise

Heart rate variability (HRV) and systolic blood pressure variability (BPV) during incremental exercise at 50, 75, and 100% of previously determined ventilatory threshold (VT) were compared to that of resting controlled breathing (CB) in 12 healthy subjects. CB was matched with exercise-associated respiratory rate, tidal volume, and end-tidal CO(2) for all stages of exercise. Power in the low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, >0.15-0.4 Hz) for HRV and BPV were calculated, using time-frequency domain analysis, from beat-to-beat ECG and non-invasive radial artery blood pressure, respectively. During CB absolute and normalized power in the LF and HF of HRV and BPV were not significantly changed from baseline to maximal breathing. Conversely, during exercise HRV, LF and HF power significantly decreased from baseline to 100% VT while BPV, LF and HF power significantly increased for the same period. These findings suggest that the increases in ventilation associated with incremental exercise do not significantly affect spectral analysis of cardiovascular autonomic modulation in healthy subjects.