Amniotic fluid embolism: A comparison of two classification systems in a retrospective 8-year analysis from two tertiary hospitals.

OBJECTIVE: Amniotic fluid embolism (AFE) is a rare life-threatening complication in obstetrics, but the diagnosis lacks a consensual definition. The objective of this study was to compare two different AFE classification systems by analysing the AFE cases from two university hospitals. MATERIAL AND METHODS: In this retrospective study, all patients with a strong suspicion of AFE between 2014 and 2021 at two university hospitals, LMU Women's University Hospital Munich, and Women's University Hospital Basel, were included. Patient records were checked for the ICD-10 code O88.1 (AFE). Diagnoses were confirmed through clinical findings and/or autopsy. The presence of the diagnostic criteria of the Society of Maternal foetal Medicine (SMFM) and the AFE Foundation (AFEF) and of a new framework by Ponzio-Klijanienko et al. from Paris, France, were checked and compared using Chi-square-test. RESULTS: Within our study period, 38,934 women delivered in the two hospitals. Six patients had a strong suspicion of AFE (0.015%). Only three of six patients (50%) presented with all the four diagnostic criteria of the SMFM/AFEF framework. All six patients met the criteria of the modified "Paris AFE framework". CONCLUSION: Using the "Paris AFE framework" based exclusively on clinical criteria can help clinicians to diagnose AFE, anticipate the life-threatening condition of the patient and prepare immediately for best clinical care.

Delivery room desaturations and bradycardia in the early postnatal period of healthy term neonates - a prospective observational study.

OBJECTIVE: It has been suggested that desaturations and bradycardia precede acute life-threatening events (ALTE) and that ALTE is more common in the delivery room than later in life. However, frequency, duration and severity of desaturations in the first hours of life and additional risk factors have not readily been studied. METHODS: Term neonates (n = 100) were monitored for the first two hours after birth by pulse oximetry. The impact of maternal and perinatal factors on the frequency and severity of desaturations (<85%) and bradycardia (<80/min) was evaluated. RESULTS: Desaturations were detected in 30%, prolonged desaturations in 25% of infants. Desaturations were observed significantly more often in infants born by planned Cesarean section (pCs) compared to other modes of delivery (pCs 20/49; others 10/51; p = .029). Desaturations were also more frequent in infants diagnosed with neonatal infection (NI) or infants born to a mother with gestational diabetes (GDM), although not significantly. No bradycardia <80/min was detected. CONCLUSIONS: In our collective 4% of healthy term neonates had prolonged, clinically relevant desaturations in the first hours after birth. The mode of delivery and maternal risk factors may increase the risk for these events. However, our cohort was too small to detect any ALTE or SIDS and determine potential risk factors for these events. Our data lay ground for a large-scale prospective trial to investigate whether the mode of delivery could be an indication for general pulse oximetry monitoring of newborn in the delivery room.

Two different prenatal imaging cerebral patterns of tubulinopathy.

To illustrate the prenatal cerebral imaging features associated with tubulinopathy, we report on five affected fetuses from unrelated families, with a de-novo heterozygous variant in a tubulin gene (TUBA1A, TUBB2B or TUBB3). We identified two distinct prenatal imaging patterns related to tubulinopathy: a severe form, characterized by enlarged germinal matrices, microlissencephaly and a kinked brainstem; and a mild form which has not been reported previously in the prenatal literature. The latter form is associated with non-specific features, including an asymmetric brainstem, corpus callosal dysgenesis, a lack of Sylvian fissure operculization and distortion of the anterior part of the interhemispheric fissure with subsequent impacted medial borders of the frontal lobes, the combination of which, in the absence of additional extracerebral anomalies, is highly suggestive of tubulinopathy. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The mechanically stable steam sterilization of bone grafts.

Bone allografts are the standard material used in augmentative bone surgery. However, steam-sterilized bone has a low mechanical stability and limited ossification based on low strain-adapted bone remodelling. Here we describe a new technique which allows the bone to be autoclaved without losing its mechanical stability and osteoconductivity. The compression strength of the new material was compared with steam-sterilized and fresh bone based on mechanical testing using bone cylinders (n=30/group). Allogeneic new material and fresh bone were press-fit implanted into rabbit patellar grooves and examined under fluorescent light and conventional microscopy. Initial healing was assessed after 30 d (n=5/group). Osseous integration and remodelling was studied after 100 d (n=12/group). Steam-sterilized bone showed no mechanical stability, whereas the new material was stiff and had compression curves similar to fresh bone; both groups showed equal degrees of direct ossification after 30 d, advanced bony ingrowth and remodelling after 100 d, and similar ingrowth depths on histomorphometric analysis. The new method preserved the stiffness and osteoconductivity of bone after steam sterilization, and microstructure, mineralization, and composition were conserved. This technique could be useful for bone banking in Third World countries.

Shock waves: a novel method for cytoplasmic delivery of antisense oligonucleotides.

Intracytoplasmic delivery of oligonucleotides (ODN) can improve ODN-based strategies such as the antisense approach and the use of immunostimulatory CpG dinucleotide containing ODN. Shock waves are established for the treatment of nephrolithiasis and other diseases. Here we describe the use of shock waves as a new physical method for the direct transport of antisense ODN into the cytoplasm and the nucleus of cells. Human peripheral blood mononuclear cells together with antisense ODN were exposed to shock waves generated by an electrohydraulic lithotripter. ODN uptake was examined by flow cytometry and fluorescence microscopy. By optimization of physical parameters we achieved the transfer of high amounts of ODN which were detected within less than 5 min after shock wave exposure, with viability of cells higher than 95%. Transfection of human peripheral blood mononuclear cells with an antisense ODN directed against tumor necrosis factor (TNF) alpha resulted in a reduction in lipopolysaccharide-induced TNF production by 62% (n=5, P=0.006). Specificity of TNF suppression was confirmed with a four-mismatch oligonucleotide. Positive atmospheric pressure abolished antisense-mediated inhibition of TNF synthesis by blocking shock wave-induced cavitation and formation of oscillating air bubbles. Electroporation was less effective. The use of shock waves is thus an efficient physical tool for ODN delivery to cells. Shock waves may allow the evaluation of target proteins in cell types difficult to transfect with other methods and thus may improve the antisense technique for the analysis of unknown genes.

Impaired tensile strength after shock-wave application in an animal model of tendon calcification.

Extracorporeal shock-wave application facilitates dissolution of rotator cuff calcifications. Therefore, disappearance or disintegration of tendon calcifications by shock waves might be appropriate for any kind of tendon calcification. Here, shock waves with various energy flux densities were applied to the mineralized medial gastrocnemius tendon of turkeys as an animal model. After application of shock waves in vivo, with energy flux density of 0.6 mJ/mm(2), histologic examination and microradiography did not show dissolution or disintegration of tendon calcifications. After shock-wave application in vitro, even for energy flux density of 1.2 mJ/mm(2) neither dissolution nor disintegration of tendon calcifications were observed. Biomechanical testing revealed significant impairment of tensile strength following shock-wave application in vitro, with energy flux density of 1.2 mJ/mm(2), but not with 0.6 mJ/mm(2). These results are important for considerations of clinical extracorporeal shock-wave application on tendon calcifications, as well as on tendon ossifications.

Shock wave permeabilization with ribosome inactivating proteins: a new approach to tumor therapy.

Extracorporeal shock waves are high-pressure pulses of microsecond duration clinically used for lithotripsy. Recently, shock waves been shown to cause a transient increase of the permeability of the cell membrane. We therefore hypothesized that shock waves might be able to transfer tumoricidal agents into tumor cells and examined this in vitro and in vivo. In vitro, the ribosome inactivating proteins gelonin and saporin were transferred into L1210, SSK2, and HeLa cells, and dose-response curves were established. The drug concentration that reduced the cell proliferation by 50% (IC50) was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the enhancement factors from shock wave application were calculated. It was found that shock waves enhanced the action of gelonin from 900-fold in L1210 cells to 40,000-fold in HeLa cells and the action of saporin from 300-fold in L1210 cells to 15,000-fold in HeLa cells. In vivo, the effect of gelonin and saporin was assessed in a murine tumor model. SSK2 fibrosarcoma tumors locally grown in C3H mice were treated with shock waves after i.p. administration of gelonin or saporin. Shock wave application delayed the tumor growth, and long-term remissions lasting >180 days were induced in 40% of the animals. In conclusion, shock waves enhanced the action of ribosome inactivating proteins and led to complete tumor remissions. The local transfer of toxic substances by shock waves into tumors constitutes a new approach to a local tumor therapy.

Extracorporeal shock waves act by shock wave-gas bubble interaction.

The effect of extracorporeal shock waves on hemoglobin release from red blood cells was recently found to be minimized under minute static excess pressure. It was proposed that this can be explained by shock wave-gas bubble interaction. We substantiated this further by two experiments by applying shock waves to suspended human RBC in a lithotripter at a lower frequency (1 pulse every 5 s) and by administering just a single or 2 strong shock waves at 30 kV. Compared to the usual application rate of 1 discharge per s, the lower frequency reduced the hemoglobin release under minimal static excess pressure in the range from 0-100 kPa. A single strong shock wave released a small amount of hemoglobin at ambient pressure and a similar amount at 200 kPa excess pressure. Two strong shock waves increased the hemoglobin release considerably at ambient pressure when there was a 1- or a 10-s pause between them. Under 200 kPa excess pressure, the hemoglobin release was minimal. A similar low hemoglobin release was also found with 1 shock at ambient and the other at excess pressure. The results are interpreted as clear evidence of shock wave-gas bubble interaction as a dominant mechanism of shock wave action.

Shock wave permeabilization as a new gene transfer method.

Uptake of naked functional DNA into mammalian cells can be achieved by a number of physical methods. However, for most of these techniques possibilities for therapeutic in vivo applications--especially to solid organs--are often limited. In this report, we describe shock wave permeabilization as a new physical gene transfer method, which can be easily applied, provides great flexibility in the size and sequence of the DNA molecules to be delivered, and which should exhibit an advantageous security profile in vivo. Upon exposure to lithotripter-generated shock waves eukaryotic cells display a temporary increase in membrane permeability. This effect was shown to be caused by cavitation resulting in the transient generation of cell pores which allows the direct transfer of naked plasmid DNA. Shockwave transfection of a variety of cell lines was demonstrated. Since shock waves can be well focused within particular body regions, future applications of extracorporally generated shock waves to tissues simultaneously perfused with DNA solutions might open up the possibility of achieving a regionally enhanced in vivo gene transfer.

Minimal static excess pressure minimises the effect of extracorporeal shock waves on cells and reduces it on gallstones.

The effects of extracorporeal shock waves on haemoglobin release, membrane permeabilisation and stone fragmentation were examined at minimal static excess pressures. Shock waves from an electrohydraulic lithotripter were applied at 15, 20 and 25 kV to red blood cells in plastic pipettes pressurised with 0, 30, 50, 75, 100, 200, 300 and 400 kPa of static excess pressure; the freed haemoglobin was determined as a marker of cell destruction. Using 15-kV discharges, 30-kPa excess pressure reduced the freed haemoglobin from 1.21 g/L at ambient pressure to 0.39 g/L, 20-kV discharges reduced it from 2.01 g/L to 0.92 g/ L and 25-kV discharges from 2.56 g/L to 1.61 g/L. Haemoglobin values at 400-kPa excess pressure were reduced to 0.03 g/L (15-kV discharges), 0.07 g/L (20-kV discharges) and 0.09 g/L (25-kV discharges), which is a 95%-97% reduction of the values obtained at ambient pressure. There was a steep initial drop from 30-100 kPa excess pressure followed by a plateau at low level. Propidium iodide uptake by L1210 tumour cells, a marker for transient membrane permeabilisation by shock waves, was reduced by 90% at these slight excess pressures. Stone fragmentation was also suppressed by excess pressure yet not as markedly as at cells; 100 kPa reduced the amount of gallstone fragments by 20%, and 400 kPa reduced it by 65%. A further reduction, by 93%, was obtained when 1-MPa excess pressure was applied to gallstones in a Plexiglas cylinder. Shock wave-gas bubble interaction has been previously proposed to mediate the shock wave action. It is suggested that the excess pressure reduced the size or number of the bubbles, thus reducing this interaction, at least in the case of the cellular effects. The reduced effect of shock waves on cells, in contrast to the effect on stones, might open up a new approach to the design of lithotripters that would reduce tissue damage yet keep fragmentation up at a similar level.

Acoustic energy determines haemoglobin release from erythrocytes by extracorporeal shock waves in vitro.

Haemoglobin release from erythrocytes by extracorporeal shock waves from an electrohydraulic lithotripter was quantified and correlated with the acoustic energy administered to the cell container. Cells were exposed in 2-, 5.9-, and 10.5-mL vials to 100 shock waves delivered at a low, medium and high lithotripter output setting, both with and without covering of the central ellipsoidal axis by a metal cage. Using the identical set-up, previous experiments had shown that the fragmentation efficiency was linearly correlated with the delivered acoustic energy. As a result, shock waves generated from 0.83 microgram mJ-1 (in 2-mL vials) to 1.53 micrograms mJ-1 (in 10.5-mL vials) haemoglobin. At all vial types, the amount of haemoglobin correlated linearly with the delivered acoustic energy (r = 0.96 in 2-mL, r = 0.97 in 5.9-mL and r = 0.98 in 10.5-mL vials). It was independent of the presence of the cage.

[Biological effect of shock waves--more than "just" lithotripsy?]. / Biologische Wirkung von Stosswellen--mehr als "nur" Steinzertrümmerung?

After their introduction into medicine for kidney stone lithotripsy, extracorporeal shock waves have gained an established or promising role in the treatment of bileduct, pancreatic and salivary stones during the last years. Treatment of gallbladder stones is possible in a large proportion of patients, yet is cumbersome. Beyond lithotripsy, treatment of pseudarthrosis by shock waves reveals positive results. The role of shock waves in the treatment of soft tissue pain is at present unknown. There is a potential for further therapeutic applications of shock waves since shock waves exert a strong biological effect on tissue which is mediated by cavitation. Experiments using shock waves for tumor therapy have shown some promising results, yet devices which generate other waveforms than lithotripters are probably better suited. Shock waves cause a transient increase in the permeability of the cell membrane, and this might lead to further applications of shock waves.

Biological effects of shock waves: in vivo effect of high energy pulses on rabbit bone.

Extracorporeal shock waves have recently been introduced to treat pseudarthrosis and aseptic bone necrosis. Only little information exists up to now about the morphological effects of shock waves on normal bone. To study both their acute effect on bone and their long-term effect on its remodelling, 1500 shock waves generated with a Dornier XL1 experimental electrohydraulic lithotripter were applied at 27.5 kV to 19 rabbits divided into five groups. Changes were evaluated after 6, 11, 41, 59 and 85 days. The discharges were focused to the right femur 1 cm above the knee joint. Bone remodelling was assessed in four groups by four-colour fluorescent labelling with labels administered sequentially over 8-day periods during the first month after shock-wave application. Radiographs were taken at dissection to detect fractures. As a result, shock waves were found to induce periosteal detachment with subperiosteal haemorrhages and to press marrow contents out of the medullary cavity. In the medullary cavity, diffuse haemorrhages, haematomas and foci of fractured and displaced bony trabeculae were found. The bone cortex and the knee joint were normal. Radiographs showed lucencies in the marrow but no fractures. During the weeks following shock-wave application, there was intense apposition of new cortical bone resulting in considerable cortical thickening while trabecular remodelling in the medullary cavity was only minor. The displacement of bony trabeculae and marrow contents point to the action of cavitation as the major mechanism of shockwave damage to bone.

Effect of shock waves and cisplatin on cisplatin-sensitive and -resistant rodent tumors in vivo.

The effect of a combination of shock waves with cisplatin was examined in vivo with subcutaneously implanted amelanotic melanomas (A-Mel 3) in Syrian golden hamsters and cisplatin-sensitive or cisplatin-resistant fibrosarcoma (SSK2/0 and SSK2/R2) in C3H mice. In all 3 tumor models, 4 treatment modalities were compared: control, cisplatin treatment, shock waves and the combination of shock waves and cisplatin. Shock waves significantly delayed tumor growth in all 3 tumor models when compared to the respective control group. Cisplatin alone delayed the growth of A-Mel 3 and SSK2/0, whereas SSK2/R2 remained uninfluenced by the drug. In all 3 tumor models the combined treatment with shock waves and cisplatin additively and significantly delayed tumor growth. In A-Mel-3-bearing animals the combined treatment significantly increased survival time. The growth of SSK2/0 and SSK2/R2 tumors was delayed to a similar extent by the combined treatment modality as compared to shock-wave treatment alone. This indicates that the cisplatin resistance of SSK2/R2 tumors has been overcome by the simultaneous shock wave treatment. An increased intracellular cisplatin accumulation in the tumors due to shock wave exposure is suggested as the mechanism of interaction between shock waves and cisplatin.

Permeabilization of the plasma membrane of L1210 mouse leukemia cells using lithotripter shock waves.

Permeabilization of L1210 cells by lithotripter shock waves in vitro was monitored by evaluating the accumulation of fluorescein-labeled dextrans with a relative molecular mass ranging from 3,900-2,000,000. Incubation with labeled dextran alone caused a dose- and time-dependent increase in cellular fluorescence as determined by flow cytometry, with a vesicular distribution pattern in the cells consistent with endocytotic uptake. Shock wave exposure prior to incubation with labeled dextran revealed similar fluorescence intensities compared to incubation with labeled dextran alone. When cells were exposed to shock waves in the presence of labeled dextran, mean cellular fluorescence was further increased, indicating additional internalization of the probe. Confocal laser scanning microscopy confirmed intracellular fluorescence of labeled dextran with a diffuse distribution pattern. Fluorescence-activated cell sorting with subsequent determination of proliferation revealed that permeabilized cells were viable and able to proliferate. Permeabilization of the membrane of L1210 cells by shock waves in vitro allowed loading of dextrans with a relative molecular mass up to 2,000,000. Permeabilization of tumor cells by shock waves provides a useful tool for introducing molecules into cells which might be of interest for drug targeting in tumor therapy in vivo.

Destruction of gallstones and model stones by extracorporeal shock waves.

The disintegration effectivity of an electrohydraulic lithotripter was evaluated by determining the acoustic energy that had to be applied, until all fragments of three artificial materials and human gallstones were cleared from a basket of 2.8 mm mesh size. The lithotripter had either an open ellipsoid, or the ellipsoidal axis was covered with a metal cage as used in clinical lithotripters to house the ultrasound scanner. Fragmentation was assessed at a low, medium and high voltage setting using 9 and 16 mm breeze block marbles, considered to be primarily fragmented by a cavitation-mediated mechanism; 16 mm glass marbles, considered to be primarily fragmented by a direct shock wave effect; 12 and 15 mm plaster balls as commonly used to monitor lithotripter output; and gallstones with a mean diameter of 16 mm. As a result, the acoustic energy for the disintegration of 9 and 16 mm breeze block marbles was 620 and 670 mJ cm-3, of glass marbles 3369 mJ cm-3, of 12 and 15 mm plaster balls 1599 and 1764 mJ cm-3 and of gallstones 8050 mJ cm-3. It was largely independent of pulse energy, specimen size and configuration of the shock wave source. It is concluded that acoustic energy is a major determinant of disintegration, independent of the presumed mechanism of destruction.

Biological effects of shock waves: induction of arrhythmia in piglet hearts.

During lithotripsy by electrohydraulic or electromagnetic lithotripters, the application of extracorporeal shock waves has to be synchronized with the electrocardiogram to reduce the induction of arrhythmias. The relation between the refractory period of the cardiac cycle and arrhythmia induction by shock waves, and the underlying mechanism have so far not been examined. In this experiment, the cardiac response to shock waves administered at 20 kV by an electrohydraulic lithotripter was assessed in nine piglets. The focus was positioned 5, 10 and 15 cm caudal to the apex of the left ventricle, and in some piglets also at the apex. The interval following the R-wave was determined during which the heart was refractory to shock wave stimulation by either single discharges or shock-wave bursts, i.e., groups of discharges separated by 10 ms intervals. This mechanical refractory period was compared to its electrical counterpart, which was determined by transvenous intracardiac atrial stimulation. As a result, mechanical refractory periods following the R-wave were at 5 cm distance 60 ms for single discharges and 70 ms for bursts (medians; range 10-180 ms); both stimulation modes were highly correlated (r = 0.88). While a similar result was obtained with the focus positioned directly at the cardiac apex, at 10 cm distance from it, bursts elicited a cardiac response significantly more often (in nine vs. two piglets). At 15 cm distance, no response was obtained at all. Both mechanical and electrical atrial refractory periods were in a similar range.(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal shock waves stimulate frog sciatic nerves indirectly via a cavitation-mediated mechanism.

Shock waves (SWs) are single pressure pulses with amplitudes up to over 100 MPa, a rise time of only a few nanoseconds, and a short duration of approximately 2 microseconds. Their clinical application for stone destruction causes pain, indicating nerve stimulation by SWs. To examine this phenomenon, sciatic nerves of frogs were exposed to SWs in an organ bath. The SWs were generated with an experimental Dornier lithotripter model XL1 at an operating voltage of 15 kV. The nerves were mounted in a chamber which allowed electrical nerve stimulation and the registration of electrically and SW-induced compound action potentials (SWCAPs). The chamber was filled with frog Ringer's solution. In a standardized protocol. The first experiment established that 95.0 +/- 4.7% of administered SWs induced action potentials which were lower in amplitude (1.45 +/- 1.14 versus 1.95 +/- 0.95 mV, p = 0.004) but similar in shape to electrically induced compound action potentials. In a second experiment, it was shown that the site of origin of the SWCAPs could be correctly determined by simultaneous recording of action potentials at both ends of the nerve. The mechanism of shock wave stimulation was examined by experiments 3 and 4. In experiment 3, in contrast to the previous experiments, SW exposure of the nerves was performed 6 cm outside the shock wave focus. This resulted in a mean probability of inducing a SWCAP of only 4%. After gas bubble administration, this probability increased to 86% for the first SW released immediately after bubble application and declined to 56% for the second, 21% for the third, to 0 for the 10th SW after fluid injection. This indicates that cavitation, the interaction between shock waves and gas bubbles in fluid or tissues, was involved in SWCAP generation. In experiment 4, nerves were again exposed in the focus, however, the Ringer's solution surrounding the nerve was replaced by polyvinyl alcohol (PVA). PVA is a solution with low cavitation activity.In PVA, the excitability was markedly diminished to 11.0 +/- 5.1% compared with 96.0 +/- 4.4% in control nerves exposed in Ringer's solution. In conclusion, bioeffects of SWs on nervous tissue appear to result from cavitation. It is suggested that cavitation is also the underlying mechanism of SW-related pain during extracorporeal SW lithotripsy in clinical medicine.