In Vivo Effects of Dexmedetomidine on Laser-Doppler Flow and Pial Arteriolar Diameter

Background: The alpha2 -adrenergic agonist dexmedetomidine alters global cerebral blood flow (CBF). However, few studies have investigated the action of dexmedetomidine on the cerebral microcirculation. This investigation examined the effects of dexmedetomidine on (1) regional CBF in the rat cerebral cortex using laser-Doppler flowmetry and (2) on pial arteriolar diameter.

Methods: Halothane-anesthetized rats were fitted with instruments to measure CBF as determined by laser-Doppler flow (CBFldf) or to measure pial arteriolar diameter by preparing a cranial hollow deepened until a translucent plate of skull remained, thereby maintaining the integrity of the cranial vault. In both groups, 20 micro gram/kg dexmedetomidine was infused intravenously. Thirty minutes later, the mean arterial pressure was restored to control values with an infusion of phenylephrine (0.5 to 5 micro gram/kg/min).

Results: Administration of dexmedetomidine was associated with decreases in end-tidal and arterial carbon dioxide. The CBFldf and pial arteriolar diameter were measured during normocapnia (controlled carbon dioxide) and during dexmedetomidine-induced hypocapnia. Intravenous administration of dexmedetomidine significantly decreased systemic arterial pressure concurrent with a decrease in CBFldf (22% in normocapnic animals, 36% in hypocapnic animals). Restoration of mean arterial pressure increased CBFldf in normocapnic but not in hypocapnic animals. Similarly, dexmedetomidine significantly reduced pial vessel diameter in both normocapnic (9%) and hypocapnic animals (17%). However, vessel diameters remained decreased in the normocapnic and hypocapnic animals after the mean arterial pressure was restored.     

A New Case of Hairy Elbows Syndrome (Hypertrichosis Cubiti)

Abstract: Hypertrichosis cubiti, also named hairy elbows syndrome (HES), is an uncommon variety of congenital, circumscribed hypertrichosis in which a remarkable amount of long vellus hair is localized on the extensor surfaces of the upper extremities. Usually, this condition appears in infancy, increases during early childhood, and regresses spontaneously at puberty. The mode of inheritance is not elucidated, and the condition presents in a sporadic or familial form. In most patients HES is not associated with any other physical abnormalities, although short stature and other developmental disorders have been described in some. An 8-year-old girl affected with HES is reported. The literature on this subject is reviewed, and some clinical and etiopathogenic aspects are discussed.     

Tripe Palms: A Cutaneous Marker of Internal Malignancy

Tripe palms is a distinctive paraneoplastic cutaneous sign which is frequently associated with internal malignancy, specially carcinomas of the lung and stomach. We describe a patient with ovary carcinoma who showed a curious rugose thickening of the palms with accentuation of the normal dermatoglyphic ridges. The lesions were a specially prominent on the fingertips. The patient also showed classical acanthosis nigricans in the axillae and groin. The soles were spared. Histopathologic findings in palmar lesions consisted of an undulant epidermis, with hyperkeratosis, acanthosis, and papillomatosis. Excision of the ovary carcinoma was followed by complete regression of the cutaneous lesions. We review the literature about tripe palms and discuss the relationship between this striking cutaneous manifestation and internal malignancy.     

Abnormal internal carotid artery in the middle ear and severe otorrhagia after myringotomy

We present a clinical-surgical case of a 72-year-old woman referred from another Hospital due to presentation of otorrhagia following myringotomy. We later determined by means of imaging studies that it was a case of an aberrant internal carotid artery. All masses in the middle ear, especially pulsing masses, must be studied by imaging methods such as computerized tomography and, preferably, magnetic resonance angiography.     

Prophylaxis of venous thromboembolism

The recommendations on venous thromboprophylaxis have been updated on the basis of current evidence reviewed by a multidisciplinary team. The problem has been approached with regard to its relevance in both surgical and nonsurgical patients. It should be noted that these recommendations were drawn up for use in Spain and, therefore, should be implemented with the drugs and therapeutic practices authorized and generally accepted in this country.     

Health care professionals: what do they know about organ donation?

BACKGROUND: Although donor detection is influenced by the legal system and family refusal, underreporting due to erroneous knowledge of donation criteria and a lack of familiarity with the procedure among medical professionals is also a contributing factor. OBJECTIVE: To investigate the outlook of critical health professionals participating in our postgraduate courses (2001 to 2006) about organ donation. METHODS: We administered an in-depth survey, evaluating attitudes, knowledge, roles, and experiences related to organ and tissue donation and transplantation, to 350 participants before and after the postgraduate courses. RESULTS: We collected 690 surveys from 350 attendees. In the first survey, 280 (80%) of them showed a positive attitude toward organ donation, 210 (60%) toward tissue donation, and 24 (7%) declared lack of knowledge about the subject. Only 175 (50%) had relatives who had donated organs. Sixty-three participants (18%) believed brain death is not equivalent to death, 176 (50%) claimed a lack of adequate training in this area, and 211 (60%) felt uncomfortable approaching families for donation. Only 88 (25%) were able to state the percentage of people receiving an organ in Spain, and 36 (10%) reported the correct number. After the course, the participants declared progress in attitudes toward and comfort levels with donation. Furthermore, family refusal in our hospital decreased from 33% to 8% to 11%. CONCLUSION: Continuous training of health care professionals about transplant, the legal system, and communication skills are crucial for successful organ and tissue donation.     

Novel pharmacological targets based on receptor heteromers

Studies performed in the last 10 years have provided solid evidence indicating that G-protein-coupled receptors are expressed on the plasma membrane as homo and heterodimers. The first consequence of this fact is that homo and heterodimers are the true targets of natural (hormones, neurotransmitters) and synthetic drugs. Furthermore a given receptor in a heteromer may display a different functional and/or pharmacological profile than the same receptor characterized as monomer or as homodimer. Recent evidence indicates that receptor heteromers are sensors that lead to a fine-tuning in neurotransmission or hormone regulation; mainly this is achieved by a modification of the signaling pathways activated via a given receptor when it is forming a given heteromer. Quite often antagonists display variable affinities when a given receptor is expressed with different heteromeric partners. This fact should be taken into account in the development of new drugs. Finally it should be pointed out that radioligand binding data has to be analyzed by a model that considers receptors as dimers and not as monomers. This model provides a novel approach to characterize drugs interacting with the orthosteric center (agonists/antagonists) or with allosteric centers (allosteric regulators).