Holographic interferometry forIn Vitro investigation of bioprosthetic valves

Dysfunction of heart valve prostheses—mechanical as well as biological—is a common problem in cardiac surgery. The reasons for the valve failures are still not well understood. Biological valves especially have an unsatisfactory durability; degeneration and calcification very often lead to the failure of the valves. In our opinion, hidden defects present in the valve material prior to implantation of the valves is a plausible explanation for the dysfunction. Hitherto there has been no technique to detect these defects without destructing the specimen. Holographic interferometry proved to be applicable forin vitro evaluation of mechanical heart valve prostheses. In the present paper we describe application of this method to biological valves. Nine porcine bioprostheses and four fresh porcine aortic valves were investigated by means of holographic interferometry. In eight of nine bioprostheses, the results showed irregularities of the leaflet structure which depend on anomalies of the connective tissue of the leaflets of the valves. To make sure that these findings are not due to normal variations of the morphology, the investigations were carried out with fresh and unfixated porcine aortic valves. In the latter, no such anomalies of the structure were detected. The results obtained confirm the above hypothesis on the origin of the later valve dysfunction. Thus, holographic interferometry tests of bioprostheses prior to their implantation prevent the use of potentially dysfunctional valves.Presented at the 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993     

Echocardiography findings before and following beta-irradiation (106Ru/106Rh) of choroid melanoma

Echographic follow-up examinations were performed in 72 patients in whom a choroidal melanoma was treated with (106Ru/106Rh) applicators. The observation period was between 6 and 15 months. Echographic measurement of tumor prominence and assessment of the degree of reflection proved to be important indicators for judging the success of beta radiation therapy. If the prominence diminishes and the degree of reflection increases after treatment, regression of the tumor may safely be assumed to have occurred. Apart from an increase in the prominence of the tumor, a constantly low or even falling level of reflection are signs of a less favorable prognosis.     

Volar plate osteosynthesis in typical and atypical distal radius fractures]

28 patients with a fracture of the distal end of the radius were treated by a T-plate osteosynthesis through the volar approach. There were 7 unstable distal metaphyseal fractures and 21 dislocated intra-articular fractures. 21 patients were investigated 6 months to 8 years after operation according to the scheme of Sarmiento. 17 patients had a good or excellent result, 4 patients a fair or poor result. 2 patients developed a Sudeck's dystrophy (Algodystrophy), one of them with a radial-ulnar bone bridge. The volar application of the plate is indicated for flexion and extension fractures. In cases with compression of the dorsal cortex a bone graft is indicated to improve a stable osteosynthesis. A conventional tomography on two views helps to diagnose exactly an intra-articular fracture and to decide whether to use a plate or pins and external fixation after open reduction. Remanipulation or an operation 2 weeks after trauma increases the risk of a Sudeck's dystrophy and leads to a poor result.     

Serial Testing of Postural Control After Acute Lateral Ankle Sprain

OBJECTIVE: To identify subjects' changes in postural control during single-leg stance in the 4 weeks after acute lateral ankle sprain. DESIGN AND SETTING: We used a 2 x 2 x 3 (side-by-plane-by-session) within-subjects design with repeated measures on all 3 factors. All tests were performed in a university laboratory. SUBJECTS: Seventeen young adults (9 men, 8 women; age, 21.8 +/- 5.9 years; mass, 74.9 +/- 10.5 kg; height, 176.9 +/- 7.1 cm) who had sustained unilateral acute mild or moderate lateral ankle sprains. MEASUREMENTS: Measures of center-of-pressure excursion length, root mean square velocity of center-of-pressure excursions (VEL), and range of center-of-pressure excursions (RANGE) were calculated separately in the frontal and sagittal planes during 5-second trials of static single-leg stance. RESULTS: We noted significant side-by-plane-by-session interactions for magnitude of center-of-pressure excursions in a given trial (PSL) (P =.004), VEL (P =.011), and RANGE (P =.009). Both PSL and VEL in the frontal plane were greater in the injured limbs compared with the uninjured limbs on day 1 and during week 2 but not during week 4, whereas sagittal-plane differences existed during all 3 testing sessions. Injured-limb, frontal-plane RANGE scores were greater than uninjured values at day 1 but not during weeks 2 or 4. No significant differences in sagittal-plane RANGE scores were seen. CONCLUSIONS: Postural control was significantly impaired in the injured limbs at day 1 and during week 2 after lateral ankle sprain but not during week 4. Consistent improvement in postural control measures on both injured and uninjured limbs was seen throughout the 4 weeks after ankle sprain.     

Increased Contact Time and Strength Deficits in Runners With Exercise-Related Lower Leg Pain

ContextExercise-related lower leg pain (ERLLP) is common in runners.ObjectiveTo compare biomechanical (kinematic, kinetic, and spatiotemporal) measures obtained from wearable sensors as well as lower extremity alignment, range of motion, and strength during running between runners with and those without ERLLP.DesignCase-control study.SettingField and laboratory.Patients or Other ParticipantsOf 32 young adults who had been running regularly (>10 mi [16 km] per week) for ≥3 months, 16 had ERLLP for ≥2 weeks and 16 were healthy control participants.Main Outcome Measure(s)Both field and laboratory measures were collected at the initial visit. The laboratory measures consisted of alignment (arch height index, foot posture index, navicular drop, tibial torsion, Q-angle, and hip anteversion), range of motion (great toe, ankle, knee, and hip), and strength. Participants then completed a 1.67-mi (2.69-km) run along a predetermined route to calibrate the RunScribe devices. The RunScribe wearable sensors collected kinematic (pronation excursion and maximum pronation velocity), kinetic (impact g and braking g), and spatiotemporal (stride length, step length, contact time, stride pace, and flight ratio) measures. Participants then wore the sensors during at least 3 training runs in the next week.ResultsThe ERLLP group had a slower stride pace than the healthy group, which was accounted for as a covariate in subsequent analyses. The ERLLP group had a longer contact time during the stance phase of running (mean difference [MD] = 18.00 ± 8.27 milliseconds) and decreased stride length (MD = −0.11 ± 0.05 m) than the control group. For the clinical measures, the ERLLP group demonstrated increased range of motion for great-toe flexion (MD = 13.9 ± 4.6°) and ankle eversion (MD = 6.3 ± 2.7°) and decreased strength for ankle inversion (MD = −0.49 ± 0.23 N/kg), ankle eversion (MD = −0.57 ± 0.27 N/kg), and hip flexion (MD = −0.99 ± 0.39 N/kg).ConclusionsThe ERLLP group exhibited a longer contact time and decreased stride length during running as well as strength deficits at the ankle and hip. Gait retraining and lower extremity strengthening may be warranted as clinical interventions in runners with ERLLP.     

Hemodynamic modes of ventricular assist with a rotary blood pump: continuous, pulsatile, and failure

Pulsatile operation of rotary blood pumps (RBPs) has received interest due to potential concern with nonphysiological hemodynamics. This study aimed to gain insight to the effects of various RBP modes on the heart-device interaction. A Deltastream diagonal pump (Medos Medizintechnik GmbH) was inserted in a cardiovascular simulator with apical-to-ascending aorta cannulation. The pump was run in continuous mode with incrementally increasing rotating speed (0-5000 rpm). This was repeated for three heart rates (50-100-150 bpm) and three levels of left ventricular (LV) contractility. Subsequently, the Deltastream was run in pulsatile mode to elucidate the effect of (de)synchronization between heart and pump. LV volume and pressure, arterial pressure, flows, and energetic parameters were used to evaluate the interaction. Pump failure (0 rpm) resulted in aortic pressure drops (17-46 mm Hg) from baseline. In continuous mode, pump flow compensated by diminished aortic flow, thus yielding constant total flow. High continuous rotating speed resulted in acute hypertension (mean aortic pressure up to 178 mm Hg). In pulsatile mode, unmatched heart and pulsatile pump rates yielded unphysiologic pressure and flow patterns and LV unloading was found to be highly dependent on synchronization phase. Optimal unloading was achieved when the minimum rotating speed occurred at end-systole. We conclude that, in continuous mode, a perfusion benefit can only be achieved if the continuous pump flow exceeds the preimplant (baseline) cardiac output. Pulsatile mode of support results in complex pressure and volume variations and requires accurate triggering to achieve optimal unloading.     

Placental inflammation and perinatal transmission of HIV-1

The effect of placental membrane inflammation on mother-to-child transmission (MTCT) of HIV-1 is reported. Placentas from HIV-1-infected women were examined as part of a perinatal HIV-1 project in Mombasa, Kenya. Polymerase chain reaction analysis was used to test for HIV-1 in the infants at birth and at 6 weeks. The maternal HIV-1 seroprevalence was 13.3% (298 of 2,235). The overall rate of MTCT of HIV-1 was 25.4%; polymerase chain reaction analysis revealed that of the 201 infants 6.0% (12) were already HIV-1-positive at birth (intrauterine transmission) and 19.4% (39) were infected during the peripartum period or in early neonatal life (perinatal transmission). The prevalence of acute chorioamnionitis was 8.8%, that of deciduitis was 10.8%, and that of villitis was 1.6%. Acute chorioamnionitis was independently associated with peripartum HIV-1 transmission but not with in utero MTCT (17.9% vs. 6.7%, respectively; adjusted odds ratio, 3.9; 95% confidence interval, 1.2-12.5; p =.025). Other correlates of perinatal MTCT were presence of HIV in the genital tract and in the baby's oral cavity and a high maternal viral load in peripheral blood. The adjusted population attributable fraction of 12.8% (95% confidence interval, 1.5%-22.8%) indicated that approximately 3% of MTCT could be prevented if acute chorioamnionitis was eliminated. We suggest that further research on the role of antimicrobial treatment in the prevention of chorioamnionitis and the reduction of peripartum MTCT needs to be performed.