Development of a bio-inspired optical system that mimics accommodation and lighting regulation like the human eye.

Bio-inspired optical systems have recently been developed using polarizers and liquid or rigid lenses. In this work, we propose a bio-inspired opto-mechatronic system that imitates the accommodation and regulation of light intensity as the human eye does. The system uses a polymeric lens as a cornea, an adjustable diaphragm as an iris, a tunable solid elastic lens as a crystalline lens, and a commercial sensor as a retina. We also present the development of the electronic control system to accommodate and regulate the amount of light that enters the system, for which two stepper motors, an Arduino control system, and light and movement sensors are used. The characterization of the system is presented together with the results obtained, where it can be seen that the system works in an acceptable range as the human eye does.

Right ventricular dysfunction and right ventricular-arterial uncoupling at admission increase the in-hospital mortality in patients with COVID-19 disease.

BACKGROUND: Coronavirus disease 2019 (COVID-19) frequently involves cardiovascular manifestations such as right ventricular (RV) dysfunction and alterations in pulmonary hemodynamics. We evaluated the application of the critical care ultrasonography ORACLE protocol to identify the most frequent alterations and their influence on adverse outcomes, especially those involving the RV (dilatation and dysfunction). METHODS: This cross-sectional study included 204 adult patients with confirmed COVID-19 admitted at three centers. Echocardiography and lung ultrasound images were acquired on admission using the ORACLE ultrasonography algorithm. RESULTS: Two-hundred and four consecutive patients were evaluated: 22 (11.9%) demonstrated a fractional shortening of < 35%; 33 (17.1%) a tricuspid annular plane systolic excursion (TAPSE) of < 17 mm; 26 (13.5%) a tricuspid peak systolic S wave tissue Doppler velocity of < 9.5 cm/sec; 69 (37.5%) a RV basal diameter of > 41 mm; 119 (58.3%) a pulmonary artery systolic pressure (PASP) of > 35 mm Hg; and 14 (11%) a TAPSE/PASP ratio of < .31. The in-hospital mortality rate was 37.6% (n = 71). Multiple logistic regression modeling showed that PASP > 35 mm Hg, RV FS of < 35%, TAPSE < 17 mm, RV S wave < 9.5, and TAPSE/PASP ratio < .31 mm/mm Hg were associated with this outcome. PASP and the TAPSE/PASP ratio had the lowest feasibility of being obtained among the investigators (62.2%). CONCLUSION: The presence of RV dysfunction, pulmonary hypertension, and alteration of the RV-arterial coupling conveys an increased risk of in-hospital mortality in patients presenting with COVID-19 upon admission; therefore, searching for these alterations should be routine. These parameters can be obtained quickly and safely with the ORACLE protocol.

Critical care ultrasonography during COVID-19 pandemic: The ORACLE protocol.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is characterized by severe lung involvement and hemodynamic alterations. Critical care ultrasonography is vital because it provides real time information for diagnosis and treatment. Suggested protocols for image acquisition and measurements have not yet been evaluated. METHODS: This cross-sectional study was conducted at two centers from 1 April 2020 to 30 May 2020 in adult patients with confirmed COVID-19 infection admitted to the critical care unit. Cardiac and pulmonary evaluations were performed using the ORACLE protocol, specifically designed for this study, to ensure a structured process of image acquisition and limit staff exposure to the infection. RESULTS: Eighty-two consecutively admitted patients were evaluated. Most of the patients were males, with a median age of 56 years, and the most frequent comorbidities were hypertension and type 2 diabetes, and 25% of the patients had severe acute respiratory distress syndrome. The most frequent ultrasonographic findings were elevated pulmonary artery systolic pressure (69.5%), E/e' ratio > 14 (29.3%), and right ventricular dilatation (28%) and dysfunction (26.8%). A high rate of fluid responsiveness (82.9%) was observed. The median score (19 points) on pulmonary ultrasound did not reveal any variation between the groups. Elevated pulmonary artery systolic pressure was associated with higher in-hospital mortality. CONCLUSION: The ORACLE protocol was a feasible, rapid, and safe bedside tool for hemodynamic and respiratory evaluation of patients with COVID-19. Further studies should be performed on the alteration in pulmonary hemodynamics and right ventricular function and its relationship with outcomes.

Persistent organic contaminants and steroid hormones levels in Morelet's crocodiles from the Southern Gulf of Mexico.

Effects of endocrine disruptors on reproductive variables of top predators, such as alligators and crocodiles, have long been cited. Due to their long life span, these predators provide us with historic contaminant annals. In this study we tried to test whether lifestyle (free-ranging vs. farm animals) and reproductive age of Morelet's crocodiles in Campeche, Mexico, affect the bioaccumulation of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Subsequently, we tested to see whether their concentration was related to steroid hormones (testosterone and estradiol-17ß) levels once normal cyclic hormone variation and reproductive age had been taken into account. From the group of contaminants considered (analyzed as families), only frequency of hexachlorocyclohexanes (∑HCH) and ∑PCB permitted analyses. Whereas there was a greater concentration of ∑HCH bioaccumulated by free-ranging crocodiles, ∑PCB was found in equal quantities in free-ranging and farm animals. No difference was observed in relation to reproductive age for any of the contaminants. However, ∑PCB concentrations were related to testosterone levels among female crocodiles. This androgenic effect of ∑PCB has not been reported previously. Because testosterone promotes aggressive behavior in vertebrates, excessive aggression during the estrous season, or when female crocodiles should be caring for their young, could result in reproductive failure in Morelet's crocodiles and potential long-term decline of the population.

VARSE: Android app for real-time acquisition and analysis of heart rate signals.

BACKGROUND AND OBJECTIVE: nowadays, numerous mobile applications capable of measuring the Heart Rate (HR) are continuously being launched. However, these tools do not allow to record and label the acquired HR signals while users are doing activities such as practising sports or viewing images. They do not allow to perform simultaneous HR acquisition and real-time HRV analysis, either. VARSE is an app for Android mobile devices capable of acquiring and labelling HR signals and of performing real-time HRV analysis. METHODS: VARSE was developed for Android devices. It includes functionalities to acquire HR signals from any Bluetooth device that implements the Heart Rate Profile specification (such as a chest strap), while labelling segments of the HR data in different situations. Not only can these signals be stored, but also time and frequency HRV analyses can be carried out over them. The application is distributed under the MIT license [1], and it is also available to be installed via Google Play [2]. Functionality, ease-of-use and friendliness of VARSE were evaluated employing an User Experience Questionnaire (UEQ). Its reliability was proven by comparative studies against other existing acquisition (gVARVI) or HRV analysis (RHRV) software. RESULTS: high values were obtained for all the dimensions evaluated in the UEQ, proving the quality of the application, as well as its ease-of-use and efficiency. Both HR signal acquisition and HRV analysis yielded results similar to the ones obtained using other applications. CONCLUSIONS: VARSE is a tool with complete functionality, that can be easily downloaded or installed on Android mobile devices. It can be used by anyone who wishes to record HR signals while performing different activities, and also by the medical scientific community to perform real-time HRV analyses easily. Future versions will improve its capabilities and allow its integration with other open source applications.

Focused Transesophageal Echocardiography in Critical Care: The COVID-19 Pandemic.

Background: The use of transesophageal echocardiography (TEE) is controversial in patients with COVID-19. The aim of this case series was to demonstrate the usefulness of transesophageal echocardiography in acute cardiovascular care settings in patients with COVID-19 infection. Materials and Methods: We enrolled 13 patients with confirmed SARS-CoV-2 infection admitted to the critical care unit of our center from April 1, 2020, to July 30, 2020, in which transesophageal echocardiography was performed. TOE was performed by three cardiologists with training in echocardiography. Results: The main indication was suspected infective endocarditis in four cases, venovenous extracorporeal membrane oxygenation cannulation in four cases, suspected prosthetic mitral valve dysfunction in two patients, suspected pulmonary embolism in two patients, and acute right ventricular dysfunction and prone position ventilation in one patient. The final diagnosis was confirmed in 11 patients and discarded in 2 patients. None of the operators result infected. Conclusions: TOE is safe in the context of COVID-19 infection; it must be performed in well-selected cases and in a targeted manner.

Sperm Dysfunction in the Testes and Epididymides due to Overweight and Obesity Is Not Caused by Oxidative Stress.

Obesity is a condition that has been linked to male infertility. The current hypothesis regarding the cause of infertility is that sperm are highly sensitive to reactive oxygen species (ROS) during spermatogenesis in the testes and transit through the epididymides, so the increase in ROS brought on by obesity could cause oxidative stress. The aim of this study was to evaluate whether the activity of the enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) is capable of counteracting oxidative stress in sperm. The male Wistar rat was used as an overweight and obesity model, and analysis of fertility in these groups was carried out including the control group. Serum testosterone levels were determined, and the scrotal fat, testes, and epididymides were extracted. The epididymides were separated ini0 3 principal parts (caput, corpus, and cauda) before evaluating sperm viability, sperm morphology, damage to desoxyribonucleic acid of the sperm, and ROS production. The protein content and specific activity of the three enzymes mentioned above were evaluated. Results showed a gain in body weight and scrotal fat in the overweight and obese groups with decreased parameters for serum testosterone levels and sperm viability and morphology. Fertility was not greatly affected and no DNA integrity damage was found, although ROS in the epididymal sperm increased markedly and Raman spectroscopy showed a disulfide bridge collapse associated with DNA. The specific activities of CAT and GPX increased in the overweight and obesity groups, but those of SOD did not change. The amounts of proteins in the testes and epididymides decreased. These findings confirm that overweight and obesity decrease concentrations of free testosterone and seem to decrease protein content, causing poor sperm quality. Implications. An increase in scrotal fat in these conditions fosters an increase of ROS, but the increase of GPX and CAT activity seems to avoid oxidative stress increase in the sperm without damaging your DNA.

Acute right ventricular failure in COVID-19 infection: A case series.

Severe forms of COVID-19 infection are associated with the need for invasive mechanical ventilation and thromboembolic complications; those can affect the cardiac function especially the right ventricle performance. Critical care echocardiography has rapidly evolved as the election technique in the evaluation of the critically ill patients. This technique has the advantage that it can be done at patient´s bedside and helps to provide the appropriate treatment and to monitoring maneuver's response. We present 4 patients with a confirmed COVID-19 infection who presented with sudden hemodynamic and / or respiratory deterioration, in which transthoracic echocardiogram showed acute right ventricular failure as the trigger for the event and helped to guide an early therapeutic intervention. .

[Hypertension and pregnancy]. / Hipertensión arterial sistémica en el embarazo.

Increasing evidence indicates that hypertension in pregnancy is an under recognized risk factor for cardiovascular disease (CVD). Compared with women who have had normotensive pregnancies, those who are hypertensive during pregnancy are at greater risk of cardiovascular and cerebrovascular events and have a less favorable overall risk profile for CVD years after the affected pregnancies. One factor that might underlie this relationship is that hypertensive disorders of pregnancy (pre-eclampsia, in particular) and CVD share several common risk factors (e.g. obesity, diabetes mellitus and renal disease). Alternatively, hypertension in pregnancy could induce long-term metabolic and vascular abnormalities that might increase the overall risk of CVD later in life. In both cases, evidence regarding risk-reduction interventions specific to women who have had hypertensive pregnancies is lacking. While awaiting results of large-scale studies, hypertensive disorders of pregnancy should be screened for during assessment of a woman's overall risk profile for CVD. Women at high risk must be monitored closely for conventional risk factors that are common to both CVD and hypertensive disorders of pregnancy and treated according to current evidence-based national guidelines.

[Hypertension in women]. / Hipertensión arterial sistémica en la mujer.

The cardiovascular disease is a crucial cause of morbidity and mortality in the woman mainly when they arrive at menopause. The pathophysiology and neurohormonal mechanisms widely vary with respect to the man. This finding has given the support to think that the estrogens may be playing a protector role in cardiovascular disease. However, the associated risk factors like obesity, diabetes, dislipidemia, smoking and sedentary life are increasing in an exponential form. In Mexico the population age distribution establishes that 60% of the women with hypertension are aged < 54 years old. This is reason why as factor of independent cardiovascular risk is commonest. Nevertheless, after the menopause cardiovascular mortality is greater in the woman than in the man. In this review, the importance of the new pathophysiological mechanisms and the clinical-therapeutic approach are analyzed, making emphasis in the importance of the change in the life style and also in the nutritional aspects. In Mexico the woman still have a unique role in the nutritional culture.

[Therapeutic clinical approach for the elderly patient with hypertension: recommendations for clinical practice]. / Abordaje clínico terapéutico del paciente adulto mayor con hipertensión arterial sistémica: recomendaciones para la práctica clínica.

The incidence of hypertension in the geriatric population is very high and is a significant determinant of cardiovascular risk in this group. The tendency for blood pressure to increase with age in westernized societies such as the United States may depend on environmental factors such as diet, stress, and inactivity. Our population tends to become more obese; to consume relatively greater amounts of sodium and lesser amounts of potassium, calcium, and magnesium; and to decrease exercising with increasing age. Senescent changes in the cardiovascular system leading to decreased vascular compliance and decreased baroreceptor sensitivity contribute not only to rising blood pressure but also to an impairment of postural reflexes and orthostatic hypotension. The hallmark of hypertension in the elderly is increased vascular resistance. Greater vascular reactivity in the elderly hypertensive patients may reflect decreased membrane sodium pump activity and decreased beta-adrenergic receptor activity as well as age-related structural changes. Treatment of diastolic hypertension in the elderly is associated with decreased cardiovascular morbidity and mortality. Although treatment of systolic hypertension may not decrease immediate cardiovascular mortality, it appears to decrease the incidence of stroke. The initial therapeutic approach to the elderly hypertensive patient should generally consist of a reduction in salt and caloric intake and an increase in aerobic exercise, i.e., walking. Drug therapy should be initiated with lower doses of medication with a special concern about orthostatic hypotension.

[Hypertension in children and adolescence]. / Hipertensión arterial sistémica en el niño y adolescente.

The epidemic of childhood obesity, the risk of developing left ventricular hypertrophy, and evidence of the early development of atherosclerosis in children would make the detection of and intervention in childhood hypertension important to reduce long-term health risks; however, supporting data are lacking. Secondary hypertension is more common in preadolescent children, with most cases caused by renal disease. Primary or essential hypertension is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension. Evaluation involves a through history and physical examination, laboratory tests, and specialized studies. Management is multifaceted. Nonpharmacologic treatments include weight reduction, exercise, and dietary modifications. Although the evidence of first line therapy for hypertension is still controversial, the recommendations for pharmacologic treatment are based on symptomatic hypertension, evidence of end-organ damage, stage 2 of hypertension, or stage 1 of hypertension unresponsive to lifestyle modifications, and hypertension with diabetes mellitus.

[Prevention and treatment of hypertension and coronary heart disease]. / Prevención y tratamiento de la hipertensión arterial sistémica en el paciente con enfermedad arterial coronaria.

The association between arterial systemic hypertension arterial coronary disease has been demonstrated by cumulated evidence of several epidemiological studies. Hypertension is an important independent risk factor for the development of coronary artery disease, vascular cerebral disease and nephropathy. Important advances exist in the knowledge of neurohumoral and hemodynamic factors that come together in the pathophysiology of the hypertension and in the development of coronary disease that allow to establish better strategies not only of treatment, but also of prevention, with the purpose of diminishing the cardiovascular mortality. The spectrum of the coronary artery disease secondary to atherosclerosis is wide and the strategies of treatment of hypertension must be adapted to each particular case. The treatment of both conditions needs of specific limits of agreement to the conditions of the patient and the form of presentation of each one of these disease.

[Extreme elevation of the blood pressure (hypertensive crisis): recommendations for its clinical-therapeutic approach]. / Elevación extrema de la presión arterial (crisis hipertensiva): recomendaciones para su abordaje clínico-terapéutico.

From beginnings of last century the hypertensive emergency was defined as the association of acutely elevation from the arterial pressure and the appearance of damage to end organ. At present is recognized the effects of the hypertensive emergency, the aspects of its patophysiology in which are included phenomenon of vasomotricity and the participation of different substances with vasoactives properties. The clinical presentation includes not only the manifestations of the increase of the arterial pressure, the end organ damage too; for this reason the hypertensive emergency needs the immediate reduction of the arterial tension to prevent the damage to specific organs. The treatment in every case will have to be individualized, with a wide knowledge of the characteristics of every medicament to obtain the best results. The diagnosis and treatment of the hypertensive emergencies needs often of the attention of its complications if they have appeared and later, of a treatment of support for the arterial hypertension.

[Clinical guidelines for detection, prevention, diagnosis and treatment of systemic arterial hypertension in Mexico (2008)]. / Guías clínicas para la detección, prevención, diagnóstico y tratamiento de hipertensión arterial sistémica en México (2008).

The multidisciplinary Institutional Committee of experts in Systemic Arterial Hypertension from the National Institute of Cardiology "Ignacio Chávez" presents its update (2008) of "Guidelines and Recommendations" for the early detection, control, treatment and prevention of Hypertension. The boarding tries to be simple and realistic for all that physicians whom have to face the hypertensive population in their clinical practice. The information is based in the most recent scientific evidence. These guides are principally directed to hypertensive population of emergent countries like Mexico. It is emphasized preventive health measures, the importance of the no pharmacological actions, such as good nutrition, exercise and changes in life style, (which ideally it must begin from very early ages). "We suggest that the changes in the style of life must be vigorous, continuous and systematized, with a real reinforcing by part of all the organisms related to the health education for all population (federal and private social organisms). It is the most important way to confront and prevent this pandemic of chronic diseases". In this new edition the authors amplifies the information and importance on the matter. The preventive cardiology must contribute in multidisciplinary entailment. Based mainly on national data and the international scientific publications, we developed our own system of classification and risk stratification for the carrying people with hypertension, Called HTM (Arterial Hypertension in Mexico) index. Its principal of purpose this index is to keep in mind that the current approach of hypertension must be always multidisciplinary. The institutional committee of experts reviewed with rigorous methodology under the principles of the evidence-based medicine, both, national and international medical literature, with the purpose of adapting the concepts and guidelines for a better control and treatment of hypertension in Mexico. This work group recognizes that hypertension is not an isolated disease; therefore its approach must be in the context of the prevalence and interaction with other cardiovascular risk factors such as obesity, diabetes, dislipidemia and smoking among others. The urgent necessity is emphasized to approach in a concatenated form the diverse cardiovascular risk factors, since independently of which they share common pathophysiological mechanisms, its suitable identification and control will affect without any doubt the natural history of the other concatenated risk factor. By all means that to greater participation of factors, greater it will be the global cardiovascular risk but never, however, the specific weight is due to avoid that each one has on the global cardiovascular risk. In this Second edition we try to amplify and give systematic forms for the clinical approach for the suspicion of secondary hypertension and we emphasizes that hypertension in the woman with or without menopause should be careful analyzed, and special recommendations are given for the hypertension in pregnancy. Also we have approached some aspects related to the hypertensive emergencies and other special situations. In this second version some recommendations are presented for boarding hypertension in children and adolescents.

A Background Modeling and Foreground Detection Algorithm Using Scaling Coefficients Defined With a Color Model Called Lightness-Red-Green-Blue.

This paper presents an algorithm for background modeling and foreground detection that uses scaling coefficients, which are defined with a new color model called lightness-red-green-blue (LRGB). They are employed to compare two images by finding pixels with scaled lightness. Three backgrounds are used: 1) verified background with pixels that are considered as background; 2) testing background with pixels that are tested several times to check if they belong to the background; and 3) final background that is a combination of the testing and verified background (the testing background is used in places, where the verified background is not defined). If a testing background pixel matches pixels from previous frames (the match is tested using scaling coefficients), it is copied to the verified background, otherwise the pixel is set as the weighted average of the corresponding pixels of the last input images. After the background is computed, foreground objects are detected by using the scaling coefficients and additional criteria. The algorithm was evaluated using the SABS data set, Wallflower data set and a subset of the CDnet 2014 data set. The average F measure and sensitivity with the SABS Data set were 0.7109 and 0.8725, respectively. In the Wallflower data set, the total number of errors was 5280 and the total F-measure was 0.9089. In the CDnet 2014 data set, the F-measure for the baseline test case was 0.8887 and for the shadow test case was 0.8300.

In-Vivo relation between CT attenuation value and shockwave fragmentation.

PURPOSE: To use CT attenuation numbers as a means of determining the susceptibility of an artificial stone to in-vivo fragmentation with extracorporeal shockwave lithotripsy (SWL). MATERIALS AND METHODS: Four types of artificial kidney stones having different CT attenuation values were used. One randomly selected stone was implanted in the renal pelvis of a kidney of 12 young pigs and exposed in vivo to 2500 shockwaves (21 kV) using an electrohydraulic lithotripter. Bilateral nephrectomy was performed after SWL. Fragments were strained through a mesh with a 3.1-mm grid, and the debris left on the mesh was dried and weighed. Fragmentation coefficients (FCs) were associated with CT attenuation values using a statistical model. RESULTS: The relation between FC and CT number was significant, indicating that as CT attenuation increases, FC is reduced. Larger stone fragments were obtained from stones with higher CT numbers. Initial stone weight was not a significant explanation for variations in FC. CONCLUSION: The CT values could be helpful in selecting patients for SWL in the future. However, other parameters such as stone porosity, shape, and roughness also will have to be considered.

Computerized detection of breast masses in digitized mammograms.

We propose a system to detect malignant masses on mammograms. We investigated the behavior of an iris filter at different scales. After iris filter was applied, suspicious regions were segmented by means of an adaptive threshold. Suspected regions were characterized with features based on the iris filter output and, gray level, texture, contour-related, and morphological features extracted from the image. A backpropagation neural network classifier was trained to reduce the number of false positives. The system was developed and evaluated with two completely independent data sets. Results for a test set of 66 malignant and 49 normal cases, evaluated with free-response receiver operating characteristic analysis, yielded a sensitivity of 88% and 94% at 1.02 false positives per image for lesion-based and case-based evaluation, respectively. Results suggest that the proposed method could help radiologists as a second reader in mammographic screening.

Prevalance of proteinuria in Mexico: a conjunctive consolidation approach with other cardiovascular risk factors: the Mexican Health Survey 2000.

BACKGROUND: A number of cross-sectional or serial studies have demonstrated the clinical impact of microproteinuria and macroproteinuria by identifying individuals at risk of both end-stage renal disease and major cardiovascular events. This study focused on the prevalence of proteinuria in Mexico and its relationship with other cardiovascular risk factors such as hypertension, type 2 diabetes mellitus, body mass index, smoking, age, and gender. METHODS: The prevalence of proteinuria in Mexico was obtained from the probabilistic cross-sectional national health survey performed in the year 2000. The proportion of urine dipstick samples that tested positive for protein (defined as > or =1+) in adults from 20 to 69 years of age was determined. The analysis was performed using both algebraic and multicategorical models. Potential interactions between proteinuria and other major cardiovascular risk factors were investigated. RESULTS: A total of 46,523 adult survey participants were included in the analysis. In the general population, 9.2% had proteinuria. By univariate, multivariate, and multicategorical analysis, hypertension, diabetes, obesity, and age were strongly associated with the prevalence of proteinuria (P < 0.001). However, in Mexico, the specific distribution of age groups demonstrated that the absolute number of patients without hypertension that had proteinuria is not irrelevant. To identify 1 case of proteinuria, one would need to screen 3 persons with diabetes mellitus, 5 patients with hypertension without diabetes, or 6 persons over the age of 55 years. When proteinuria is present, the probability of having a noncommunicable chronic disease or other major cardiovascular risk factor is more than 85%. CONCLUSION: Proteinuria is prevalent. When considered together, dipstick-positive proteinuria, blood pressure level, body mass index > or =30 m(2)/kg, and abnormal fasting blood glucose measured on a single occasion identifies different segments of the population. Studies such as this may be a suitable initial clinical approach to general population screening for renal and cardiovascular risk stratification.

Conversion of an HM3 lithotripter into a research device.

PURPOSE: To describe the conversion of a Dornier HM3 lithotripter into a research device and evaluate its performance. MATERIALS AND METHODS: A used HM3 lithotripter was donated to our university by the St. Thomas' Hospital in London. It was disassembled, shipped to our laboratory, partially assembled, and modified as a research lithotripter. Pressure measurements at several positions and kidney stone model fragmentation tests were performed to evaluate the modified system. Results were compared with information published by other authors and data obtained in our laboratory using another electrohydraulic research lithotripter. RESULTS: Pressure records showed typical lithotripter waveforms with a rapid rise to about 50 MPa, followed by decay to a negative peak of approximately 9 MPa. Maximum compressional peaks were obtained at F2 and 25 mm below F2. Kidney stone model fragmentation was typical for electrohydraulic shockwave lithotripters. CONCLUSIONS: Comparison of pressure measurements with data obtained by other authors on the same lithotripter several years ago indicate that the pressure waveform has not changed significantly. A much smaller water tank, a small X-Y-Z positioner, and no X-ray imaging system facilitate the use of this shockwave generator for in vitro experiments with small samples such as vials containing cell suspensions, having the advantage of a reliable, well-known, and well-characterized commercial shockwave generator.