Search results for "Flow"

Cell Line and Growth Site as Relevant Parameters Governing Tumor Tissue Oxygenation

1986

Experimental rodent tumors commonly used in radiobiology exhibit a large inter-individual variability in the oxygenation status [1,2] and in the hypoxic cell fraction [3,4]. Paramount factors contributing to this variability may be tumor growth stage or tumor size [5], the cell line used, the growth site, the use of anaesthesia and certain tumor-host interactions (e.g. tumor-induced anemia). Concerning the basic pathogenetic mechanisms through which the above mentioned parameters can modulate tumor tissue oxygenation, variations of nutritive blood flow, inherent characteristics of the cell line (e.g. respiration rate or tumor growth rate), and finally changes in the O2 transport capacity of…

Coronary artery and bypass flow measurement—basic methodology and current status

1998

Evaluation of the efficacy of the ‘nasal airflow-inducing manoeuvre’ for smell rehabilitation in laryngectomees by means of the Sniffin′ Sticks test

2011

Clin. Otolaryngol. 2011, 36, 17–23 Objective:  To determine the efficacy of the nasal airflow-inducing manoeuvre (NAIM) as a method for olfactory rehabilitation in laryngectomees by the means of the Sniffin′ Sticks test. Study design:  Prospective open interventional trial. Setting:  Tertiary academic hospital. Participants:  Thirty-seven patients after laryngectomy have been screened and 25 patients have been included into the study. The participant’s sense of smell was tested with the Sniffin′ Sticks test before and after learning the nasal airflow inducing manoeuvre. The individual level of threshold, discrimination and identification (TDI) was determined and the individual threshold, di…

Computerized estimation of quality standards for the X-ray densitometric assessment of myocardial perfusion

2003

The densitometric evaluation of heart-phase-gated digital subtraction coronary angiograms derives different parameters which provide information about coronary blood flow, myocardial perfusion, and coronary flow reserve: appearance time, rise time, mean ascending time, and maximum intensity. The reliability and reproducibility of these measurements and of the derived parameters were investigated. Four digital subtraction coronary angiograms were obtained in ten patients, including two baseline measurements and two measurements under hyperemia induced by papaverine ic. Different reproducibility results were found for the parameters, depending on the heart phase of the densogram (diastolic be…

Anteil des frühen systolischen Flussanstiegs am antegrad fließenden Gesamtvolumen bei Phasenkontrast-Flussmessungen in Atemanhaltetechnik

2005

Purpose To evaluate the contribution of early systole for the assessment of antegrade aortic flow volume by breath-hold velocity-encoded magnetic resonance (MR) flow measurements. Materials and methods Expiratory breath-hold fast low-angle shot (FLASH) phase-contrast flow measurements (temporal resolution tRes 61 msec, shared phases) perpendicular to the proximal ascending aorta and short axis true fast imaging with steady-state precession (TrueFISP) cine MR ventriculometry (tRes 34.5 msec) were performed in ten healthy male volunteers on a 1.5 T MR system (Sonata, Siemens Medical Solutions). Antegrade aortic flow volume (AFV) and left ventricular stroke volume (LV-SV) were evaluated using …

Neural conservation in skull base surgery

2002

Surgical treatment of lesions of the skull base carries significant risk to the functioning of the cerebral hemispheres, brainstem, and cranial nerves. This risk is due to both (1) problems associated with maintaining an adequate blood flow while exposing and removing the tumor and (2) direct or indirect trauma to the brain, perineural tissues, and cranial nerves. These risks may be reduced if information about possible implications of surgical maneuvers on the cerebral blood flow and on the function of the patient’s CNS and cranial nerves is available and can be monitored during surgery of the skull base. The use of EMG neuromonitoring for the facial nerve and of brainstem evoked response …

Reliability of EMA Binding Test in Diagnosis of Hereditary Spherocytosis in Italian Patients

2010

Impaired Fractional and Coronary Flow Reserve

2016

A FFR <0.80/0.75 witnesses the existence of a high-grade epicardial stenosis. In this setting, the CFR is usually also impaired since even a maximal dilation of the peripheral resistances cannot compensate for the increased epicardial resistances.

Changes in the adrenergic mechanisms of cerebral arteries after subarachnoid hemorrhage in goats.

1994

We have examined the effects of experimental subarachnoid hemorrhage (SAH), induced by delivering autologous blood into the subarachnoid space, on the adrenergic mechanisms of the goat cerebrovascular bed. To achieve this, the response to noradrenaline was recorded both in vivo, by measuring cerebral blood flow in unanesthetized animals, and in vitro, by recording isometric tension in isolated cerebral arteries. In addition, we checked the function of adrenergic innervation by measuring the tritium efflux evoked by electrical stimulation in cerebral arteries preloaded with [3H]-noradrenaline, and we examined this innervation by using both fluorescent and electron transmission microscopy. Al…

Analysis of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage with High Frequency Transcranial Duplex Ultrasound

2021

Cerebral vasospasm that occurs in the weeks after subarachnoid hemorrhage, a type of hemorrhagic stroke, contributes to delayed cerebral ischemia. A problem encountered in experimental studies using murine models of SAH is that methods for in vivo monitoring of cerebral vasospasm in mice are lacking. Here, we demonstrate the application of high frequency ultrasound to perform transcranial Duplex sonography examinations on mice. Using the method, the internal carotid arteries (ICA) could be identified. The blood flow velocities in the intracranial ICAs were accelerated significantly after induction of SAH, while blood flow velocities in the extracranial ICAs remained low, indicating cerebral…