RESUMEN
Damage to the hand caused by vibration has been observed with a range of trades and professions and in connection with various types of sport. Osseous, neurogenic and vascular lesions can lead to chronic ailments and permanent functional impairment. Hand-arm vibration syndrome (HAVS) and hypothenar/thenar hammer syndrome (HHS, THS) are interesting for vascular medicine. From a surgical perspective, there is a special significance in the fact that both syndromes are recognised occupational diseases (BK 2104 and BK 2114) which have to be acknowledged by an accident insurance doctor and in the medical report. Hypothenar/thenar hammer syndrome is caused by repeated force exerted in the region of the small finger or the ball of the thumb and is characterised by a trauma-induced lesion of the ulnar artery or radial artery that can lead to pain due to ischaemia in the acral area supplying blood to the arteries of the affected hand, usually the dominant hand. It is considered to be hand-arm vibration syndrome when there is a heightened sensitivity to coldness with vasospastic circulatory disturbance. The paper presents various clinical and functional diagnostic tests to enable a diagnosis. Doppler and duplex ultrasound exploration play an important role. Various radiological methods can augment diagnostic testing. The symptoms can be treated using medication or physiotherapy to improve perfusion by stimulating vasodilatation. An effective causal therapy is currently not available. Thus, when drawing up the medical report, particular attention should be paid to gathering information about the patient's medical history so that an unequivocal link can be made between the cause of the damage and the physical damage, as this could have sociomedical and pension-relevant consequences for the patient.
Asunto(s)
Arteriopatías Oclusivas , Mano , Humanos , Enfermedades Profesionales , Arteria Cubital , VibraciónRESUMEN
The neurohormone melatonin is synthesized by the pineal gland under the stimulation of norepinephrine (NE). Its synthesis is inhibited by acetylcholine (ACh) and by insulin. Type 2 diabetic Goto Kakizaki (GK) rats have higher insulin and lower melatonin plasma levels than healthy Wistar rats. We investigate membrane potentials and currents of isolated pinealocytes in both rat strains and the influence of NE, ACh and insulin by using the perforated patch whole cell clamp technique. Pinealocyte membranes displayed a high resting Na(+) conductance. Stimulation with NE further increased this Na(+) conductance, which led to a slight depolarization in unclamped cells. The amplitude of the NE-evoked current was similar in both rat strains but the current fraction carried by Na(+) was stronger in GK rats. Stimulation with ACh induced a transient inward current and depolarization. These effects were much more pronounced in the pinealocytes of GK rats. The NE-induced current, the ACh-induced current and the membrane depolarization were reduced by pre-administration of insulin in Wistar pinealocytes. Our results provide the first electrophysiological evidence for the modulation, by insulin, of the effects of NE and ACh in pinealocytes of normal rats. The pinealocytes of type 2 diabetic rats were not responsive to insulin. This might explain the reported correlation between the decreased insulin receptor mRNA transcript levels in GK rat pinealocytes and the lack of effect of insulin on ion channels in their cell membranes.
Asunto(s)
Acetilcolina/farmacología , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/fisiopatología , Insulina/farmacología , Potenciales de la Membrana/efectos de los fármacos , Norepinefrina/farmacología , Glándula Pineal/patología , Animales , Espacio Extracelular/efectos de los fármacos , Espacio Extracelular/metabolismo , Masculino , Meglumina/farmacología , Ratas , Ratas Wistar , Sodio/farmacologíaRESUMEN
High-frequency scanning acoustic microscopy (SAM) was used for investigation of acoustic impedance and 3D-surface topography of full alginate microspheres that act as model of artificial biological cells. Elasto-mechanical properties of the investigated specimens have been characterized by acoustic impedance. Mean surface impedance of microspheres (diameter: 300 microm) was measured with SAM at 900 MHz with a spatial resolution of 1.5 microm. The sensitivity and reproducibility of SAM had to be increased considerable to receive and quantify signals in the very low impedance region. The multilayer analysis method was used to get quantitative data of acoustic impedance with SAM at a microscopic level. 3D images show details of structure and surface topography. As a reference, bulk measurements were performed on full alginate cylinders. The acoustical impedance and the mechanical stiffness c(11) were obtained from mass density and longitudinal ultrasound velocity at 6 MHz. The impedances received with both methods are in close agreement. The results demonstrate the SAM as a powerful tool for characterizing mechano-elastical parameters as well as surface structure and topography of microspheres with high spatial resolution.