The puzzling pathophysiology of frozen shoulders - a scoping review.

PURPOSE: The pathophysiology of frozen shoulders is a complex and multifactorial process. The purpose of this review is to scope the currently available knowledge of the pathophysiology of frozen shoulders. METHODS: A systematic search was conducted in Medline, Embase and the Cochrane library. Original articles published between 1994 and October 2020 with a substantial focus on the pathophysiology of frozen shoulders were included. RESULTS: Out of 827 records, 48 original articles were included for the qualitative synthesis of this review. Glenohumeral capsular biopsies were reported in 30 studies. Fifteen studies investigated were classified as association studies. Three studies investigated the pathophysiology in an animal studies. A state of low grade inflammation, as is associated with diabetes, cardiovascular disease and thyroid disorders, predisposes for the development of frozen shoulder. An early immune response with elevated levels of alarmins and binding to the receptor of advance glycation end products is present at the start of the cascade. Inflammatory cytokines, of which transforming growth factor-ß1 has a prominent role, together with mechanical stress stimulates Fibroblast proliferation and differentiation into myofibroblasts. This leads to an imbalance of extracellular matrix turnover resulting in a stiff and thickened glenohumeral capsule with abundance of type III collagen. CONCLUSION: This scoping review outlines the complexity of the pathophysiology of frozen shoulder. A comprehensive overview with background information on pathophysiologic mechanisms is given. Leads are provided to progress with research for clinically important prognostic markers and in search for future interventions. LEVEL OF EVIDENCE: Level V.

Development of a semi-permanent mascara technology.

Many women would like their mascara beauty benefits to be available all day, every day. One way to address this desire is through a semi-permanent mascara technology that provides full mascara benefits of long, dark beautiful lashes for multiple days. To date, products promising multi-day benefits have acted more as either 'lash dyes', providing a lash darkening benefit but failing to provide fullness and length, or waterproof mascaras that do not maintain the initial beauty look over multiple days. Here, a formulation approach is described for a mascara product that is designed to be abrasion resistant, flexible and insoluble in soap and water so that the initial beauty look is maintained for multiple days. The new semi-permanent formula technology uses rosinate polymers that have a superior combination of flexibility, abrasion resistance and water and surfactant resistance. Based on principles used by the paint industry for creating durable films, the levels of the polymers and other non-volatile ingredients are balanced such that the product forms a continuous polymer film on the eyelash. Cryo-SEM is used to demonstrate that the new semi-permanent formula technology forms a film different from those formed by current mascara products. A stretch test and rub test are used to demonstrate that the new semi-permanent formula technology has superior flexibility and abrasion resistance to current mascara products. Finally, a multi-day consumer study with daily imaging of the eyes is used to demonstrate the superior wear performance of the new semi-permanent formula technology in actual usage.

Distribution of ten antibiotic resistance genes in E. coli isolates from swine manure, lagoon effluent and soil collected from a lagoon waste application field.

The prevalence of ten antibiotic resistance genes (ARGs) was evaluated in a total of 616 Escherichia coli isolates from swine manure, swine lagoon effluent, and from soils that received lagoon effluent on a commercial swine farm site in Sampson County, North Carolina (USA). Isolates with ARGs coding for streptomycin/spectinomycin (aadA/strA and strB), tetracycline (tetA and tetB), and sulfonamide (sul1) occurred most frequently (60.6-91.3%). The occurrence of E. coli isolates that carried aadA, tetA, tetB, and tetC genes was significantly more frequent in soil samples (34.0-97.2%) than in isolates from lagoon samples (20.9-90.6%). Furthermore, the frequency of isolates that contain genes coding for aadA and tetB was significantly greater in soil samples (82.6-97.2%) when compared to swine manure (16.8-86.1%). Isolates from the lagoon that carried tetA, tetC, and sul3 genes were significantly more prevalent during spring (63.3-96.7%) than during winter (13.1-67.8%). The prevalence of isolates from the lagoon that possessed the strA, strB, and sul1 resistance genes was significantly more frequent during the summer (90.0-100%) than during spring (66.6-80.0%). The data suggest that conditions in the lagoon, soil, and manure may have an impact on the occurrence of E. coli isolates with specific ARGs. Seasonal variables seem to impact the recovery isolates with ARGs; however, ARG distribution may be associated with mobile genetic elements or a reflection of the initial numbers of resistant isolates shed by the animals.

Influence of a downstream narrowing on the flow profile in a tube.

The distance over which the upstream flow conditions in a tube are disturbed by a stenosis downstream, i.e. the outlet length, was investigated for Reynolds numbers in the range 210-2900. Two methods were used, the Navier-Stokes equations were solved with a computer and a physical model was constructed and maximal velocities were measured with an ultrasound Doppler system. The computer model showed that Re number does not influence the outlet length, varying the stenosis area from 25% to 90% has an effect. However, the outlet length remained small, below 70% of the diameter of the tube. The physical model confirmed for a 75% stenosis that the outlet length is small, this method set the limit at not more than 1.2 times the tube diameter.

Numerical simulation of the pulsating catheter pump: A left ventricular assist device.

The pulsating catheter (PUCA) pump, a left ventricular assist device, consists of a hydraulically or pneumatically driven membrane pump, extracorporeally placed and mounted to a valved catheter. The catheter is introduced into an easily accessible artery and positioned with its distal tip in the left ventricle. Blood is aspirated from the left ventricle during systole and ejected into the ascending aorta during diastole. A numerical model of the PUCA pump has been developed to determine the internal diameter of the PUCA pump catheter that allows a certain blood flow. The model considers a limitation of mechanical blood damage and determines the accompanying pressure and flow profile for driving the pump. For a flow of 5 L/min, a catheter with an internal diameter of at least 6. 95 mm is required. For 3 L/min, the minimal diameter is 5.50 mm. The latter catheter can be introduced in the axillary artery, the former via the aorta during an open thorax surgical procedure. To validate the numerical model, 2 different PUCA pump configurations were tested in vitro. Results showed a good resemblance between model and in vitro behavior of the PUCA pump.

Application of a new blood-mimicking fluid in a flow Doppler test object.

OBJECTIVE: To construct and apply a flow Doppler test object and its flow rig. METHODS: In this flow rig, particular attention was given to use of a long inlet length and to ensure the absence of disturbing particles. The latter was obtained by proper degassing, use of a filter and application of a fungicide. Two blood-mimicking fluids were used, with a viscosity of 4 and 8 mPa s respectively. RESULTS: Predictable Poiseuille flow profiles were obtained. The velocity range could be extended by increasing the viscosity of the blood-mimicking fluid. Predictable axial velocities up to 2.5 m/s were obtained in an 8-mm tube and 5 m/s in a 4-mm tube. CONCLUSION: Well-defined flow conditions that can be applied to investigate clinical ultrasound Doppler systems in a number of situations have been obtained.

A simple and accurate formula for the sound velocity in water.

The sound velocity in test objects and phantoms is often measured by performing a differential measurement with pure water. To promote standardization, a simple formula for the sound velocity in water is derived that renders true values within 0.20 m s(-1) over the temperature range 15-35 C. The formula is given by c = 1404.3 + 4.7 T - 0.04 T2, with sound velocity c in m s(-1) and temperature T in C.

Skeletal muscle perfusion measured by positron emission tomography during exercise.

The applicability of H215O-positron emission tomographic (PET) imaging for the assessment of skeletal muscle perfusion during exercise was investigated in five healthy subjects performing intermittent isometric contractions on a calf ergometer. The workload of the left calf muscles was kept constant in all exercises, while that of the right calf muscles was varied. During exercise H215O distribution in the calf muscles was measured by PET. Radioactivity measured in the left calf muscles was used as a reference for the radioactivity measured in the right calf muscles. In all studies, muscles were delineated by uptake of radioactivity. Four subjects demonstrated high radioactivity in the gastrocnemius medialis muscle, in one subject high radioactivity was distributed over the triceps surae muscles. The observed muscles demonstrated also local foci of radioactivity indicating regionally enhanced tissue perfusion. The right-left ratio of radioactivity in the active muscles increased as a function of the load. We conclude that inter- and intramuscle perfusion differences can be measured during exercise by H215O-PET imaging.

Development of an example flow test object and comparison of five of these test objects, constructed in various laboratories.

Doppler test objects are used to characterise Doppler systems, both stand-alone systems and the Doppler part of so-called duplex scanners. The aim of the project partially presented here is the development and validation of an example of a Doppler test object fulfilling the requirements of the IEC 1685. The project has been carried out by nine partners of five European countries and has been funded by the European Commission. The flow Doppler test object is composed of: tissue mimicking material (TMM), blood mimicking fluid (BMF), tube (embedded in the TMM and carrying the BMF), tank flow system, including a pump and a flow meter. In the normative part of the IEC 1685, requirements are given for the values of acoustical parameters of TMM and BMF such as sound velocity, attenuation and backscattering. For BMF, requirements are given also for values of density and viscosity. In an informative (but not compulsory) annex, a description is given of a flow test object meeting these requirements as an example. 'example test object' developed during the project is composed of TMM based on agar and including SiC- and Al2O3-powders, BMF based on nylon particles suspended in water and glycerine, and a tube of c-flex, a silicon copolymer. Two tube sizes are used: 4.0 mm ID and 8.0 mm ID. During the project, very precise recipes have been developed for the composition and preparation of both TMM and BMF. Based on these recipes and a description of the construction in a design five flow test objects have been constructed in the laboratories of five participants. The test objects have been compared by measurements of the physical parameters and by Doppler measurements of the five test objects with the Doppler system. The measurements have been carried out by five observers. Inter-test object and inter-observer variabilities are determined, yielding information about usefulness of the parameters.

In vitro measurements of aerodynamic characteristics of an improved tracheostoma valve for laryngectomees.

Tracheostoma valves are often required in the rehabilitation process of speech after total laryngectomy. Patients are thus able to speak without using their hands to close the tracheostoma. The improved Groningen tracheostoma valve consists of a "cough" valve with an integrated ("speech") valve, which closes for phonation. The cough valve opens as the result of pressure produced by the lungs during a cough. The speech valve closes by the airflow produced by the lungs, thus directing air from the lungs into the esophagus at a deliberately chosen moment. An experimental setup with a computer-based acquisition program was developed to measure the pressure at which the cough valve opened and the flow at which the speech valve closed. In addition, the airflow resistance coefficient of the tracheostoma valve was defined and measured with an open speech valve. Both dry air from a cylinder and humid expired air were used. Results showed a pressure range of 1-7 kPa to open the cough valve and a flow range of 1.2-2.7 l/s to close the speech valve. These values were readily attained during speech, while the flow range occurred above values reached in quiet breathing. The device appeared to function well in physiological ranges and was optimally adjustable to an individual setting. No significant differences were measured between air from a cylinder and humid expired air. Findings showed that methods used to obtain results could be employed as a reference method for comparing aerodynamic characteristics of tracheostoma valves.

Validation of a new blood-mimicking fluid for use in Doppler flow test objects.

A blood-mimicking fluid (BMF) suitable for use in Doppler flow test objects is described and characterised. The BMF consists of 5 microns diameter nylon scattering particles suspended in a fluid base of water, glycerol, dextran and surfactant. The acoustical properties of various BMF preparations were measured under uniform flow to study the effects of particle size, particle concentration, surfactant concentration, flow rate and stability. The physical properties, (density, viscosity and particle size), and acoustical properties (velocity, backscatter and attenuation) of the BMF are within draft International Electrotechnical Commission requirements.

Calf blood flow and posture: Doppler ultrasound measurements during and after exercise.

To investigate the joint effects of body posture and calf muscle pump, the calf blood flow of eight healthy volunteers was measured with pulsed Doppler equipment during and after 3 min of rhythmic exercise on a calf ergometer in the supine, sitting, and standing postures. Muscle contractions seriously impeded calf blood flow. Consequently, blood flow occurred mainly between contractions and reached a plateau that lasted at least the final 100 s of each exercise series. After exercise the blood flow decreased much faster in the sitting and standing postures than in the supine posture. There was no difference in blood flow between various postures during the same submaximal exercise. However, subjects in the standing posture were able to perform exercise with a higher load than in the supine posture, and blood flow in the standing posture could become twice as high as in the supine posture. We conclude that calf blood flow is regulated according to needs; available perfusion pressure determined maximal blood flow and exercise; and compared with the supine posture, the standing posture and calf muscle pump increase the perfusion pressure.

Calf blood flow and posture: Doppler ultrasound calibrated by plethysmography.

A procedure was developed that enables measurement of rapid variations in calf blood flow during voluntary rhythmic contraction of the calf muscles in supine, sitting, and standing positions. During the exercise, maximum blood velocity is measured by Doppler ultrasound equipment in the popliteal artery. The Doppler signals are calibrated by plethysmography to enable calculation of blood flow during exercise in ml.100 ml-1.min-1. Knowledge of the cross-sectional area of the vessel and the angle of insonation is not required in this procedure. Evaluation of the calibration method with 10 healthy volunteers showed that for each subject a new calibration was necessary after a change in posture; the relationship between the blood flow and the maximum Doppler frequency averaged over one heart cycle was linear for each calibration.

Multipurpose ergometer for static and dynamic exercise of the calf muscles.

A calf ergometer is presented that can be used for both static and dynamic exercise in supine, sitting or standing position. During exercise each foot is fixed firmly to a pedal. During dynamic exercise the foot pedal can rotate through an angle which can be varied from 5 to 30 degrees. External work is performed only during plantar flexion. The amount of work is determined by the moment imposed to the pedal by a constant force spring and can be calculated from electrical signals that represent the angle of rotation and the moment exerted to the pedal. During static exercise the foot pedal is secured so that it cannot move.

Maximal blood flow after exercise in patients with intermittent claudication and in normal controls.

In some patients with intermittent claudication blood flow to the calf muscles after exercise was in the same range as in normals. The blood pressure was lower in all patients. The hypothesis is formulated that for these high flow patients the claudication is a result of non-uniform perfusion of the calf muscles.

Brucellosis contracted during foreign travel.

Brucellosis, a bacterial infection, is rarely seen in the United States. It occurs mostly in people who work with domestic animals and animal products. However, this patient became infected while in Yugoslavia, and diagnosis was delayed by the gap between appearance of symptoms and positive results of serologic tests. Brucellosis should be suspected in a patient with unexplained fever, especially if he or she has traveled to a country where unpasteurized dairy products are common.

The difference in blood pressure between upper arm and finger during physical exercise.

A new apparatus which measures the blood pressure in the finger continuously and yet not invasively was tested for its usefulness during exercise. It was compared with upper arm measurements in 23 volunteers during prolonged bicycle ergometry. Simultaneously, a pulse plethysmogram was recorded from another finger of the same arm, whereas in six additional volunteers Doppler measurements were carried out on the radial artery. The results show that finger systolic pressure ceased to rise at about 40% of maximal exercise; the difference with the continuously rising systolic pressure in the upper arm becoming significant at 140 W. At the same time the amplitude of the finger plethysmogram became significantly higher than its initial value, indicating distinct cutaneous vasodilation, whereas the volunteers also became hot and started to perspire. However, the radial artery 'flow', deduced from the Doppler measurements, did not change significantly during exercise. It increased sharply and markedly in the cooling down period. Simultaneously with this increase in flow, HR and both systolic blood pressures fell drastically whereas the plethysmographic amplitude remained about stable at its raised level. The results fit in with the idea that a compromise is achieved between the need for muscle activity and the need for temperature regulation. It is concluded that the Finapres functions well during exercise, but that the systolic pressure in the finger is not representative for its more central counterpart during cutaneous vasodilation. It is argued that opening up of AVAs may contribute to this pressure effect.