Opposing responses of the rat pulmonary artery and vein to phenylephrine and other agents in vitro.

BACKGROUND: Different from current cognition, our study demonstrated that adrenergic receptors agonist phenylephrine significantly relaxed isolated pulmonary artery but constricted pulmonary veins. Through comparing differences in the effects of commonly used vasoactive drugs on pulmonary artery and veins, the study aimed to improve efficiency and accuracy of isolated pulmonary vascular experiments, and to provide experimental basis for clinical drug use. METHODS: The contractile responses of pulmonary arteries and veins from twelve-week-old Male Sprague-Dawley rats to phenylephrine, arginine vasopressin (AVP), U46619, endothelin-1, and potassium chloride (KCl) were recorded, as well as the relaxation in response to phenylephrine, AVP, acetylcholine. To further explore the mechanism, some vessels was also pre-incubated with adrenergic receptors antagonists propranolol, prazosin and nitric oxide synthesis inhibitor N[gamma]-nitro-L-arginine methyl ester (L-NAME) before addition of the experimental drugs. RESULTS: Phenylephrine constricted pulmonary veins directly, but constricted pulmonary artery only after incubation with propranolol or/and L-NAME. The pulmonary artery exhibited significant relaxation to AVP with or without L-NAME incubation. AVP more clearly constricted the veins after incubation with L-NAME. Changes in vascular tension also varied from pulmonary artery to veins for KCl stimulation. Different from phenomena presented in veins, acetylcholine did not relax pulmonary artery preconstricted by KCl, U46619, and endothelin-1. CONCLUSIONS: According to the results, phenylephrine, KCl, AVP, and acetylcholine could be used to distinguish pulmonary arteries and pulmonary veins in vitro. This also suggested that the pulmonary arteries and pulmonary veins have great differences in physiology and drug reactivity.

Influence of different menstrual phases on the Bispectral Index during dexmedetomidine sedation.

To investigate the influence of different menstrual phases on the Bispectral Index (BIS) during dexmedetomidine (Dex) sedation, 40 patients with regular menstrual cycle, American Society of Anesthesiologists I-II, aged 18-40 years, undergoing selective gynecologic laparoscopic surgery, were enrolled. According to different menstrual phases and the serum progesterone concentration, they were divided into two groups: the follicular phase group (Group F) and the luteal phase group (Group L), and each group had 20 patients. Before anesthesia induction, patients were infused with an initial loading dose of Dex (1 µg/kg) for 10 minutes and then 0.5 µg/kg/h for 20 minutes. BIS and the changes in hemodynamic and respiratory parameters were recorded within those 30 minutes. Time to lower BIS to 70 and 60 in Group L was shorter than that in Group F (9.4 ± 1.3 minutes vs. 11.3 ± 2.1 minutes, p = 0.005; 11.3 ± 2.4 minutes vs. 14.0 ± 3.6 minutes, p = 0.021). The number of patients whose BIS reached 50 in Group L was greater than that in Group F (15 vs. 8, p < 0.05). The lowest BIS value in the Group L was lower than that in Group F (46.8 ± 6.3 vs. 55.3 ± 5.5, p = 0.006), and the heart rate of patients in both groups showed a decrease (p < 0.05). The sedative effect of Dex was more significant in patients during the luteal phase than during the follicular phase.

Immunofluorescence laser confocal expression and localization study of rat nerve growth guidance cues Netrin-1 and Slit2 after spinal cord injury.

OBJECTIVE: To observe the expression and distribution of adult rat axon guidance cues Netrin-1 and Slit2 at different time points after spinal cord injury and to investigate the guidance mechanism of regenerated axons. METHODS: Twenty adult Sprague Dawley (SD) rats were divided randomly into five groups with 4 in each. Four groups of them were used to make Allen's spinal cord punch models and we took materials randomly from one of them on the 2nd, 4th, 7th and 14th day respectively after operation. The left one group was taken as the control group. Immunofluorescence laser confocal scan was used to examine the co-expression and localization of Netrin-1 and Slit2 proteins in the injured site of the spinal cord. RESULTS: Within two weeks after SCI, the expression of Netrin-1 and Slit2 proteins increased temporarily and there was co-expression of them on the neuron plasma membrane. CONCLUSIONS: Synchronous high expression and co-expression of axon attractant Netrin-1 and repellent Slit2 are found in the adult rat injured spinal cord in the damaged local and vicinity parts, and probably, they act as the key regulators of axon guidance regeneration.

Reconstruction of finger pulp defect with reversed fasciocutaneous island flap from same finger.

OBJECTIVE: To investigate the clinical curative effect of reconstruction of finger pulp defect by anastomosis of reversed fasciocutaneous island flap with dorsal branch of the digital nerve of the same finger. METHODS: The restoration of finger pulp defect with fasciocutaneous island flap from the same finger was conducted in 25 cases (30 fingers) from January 2002 to June 2003. Nine patients (11 fingers) whose flaps with dorsal branch of the digital nerve anastomosed with the digital inherent nerve around the surface of the wound were Group A and the others were Group B. The follow-up was carried out at 3 and 9 months after the operation to observe the shape of finger pulp and the sense restoration between two groups. RESULTS: All flaps of 25 cases (30 fingers) survived. Three months after operation, the patients had fully grown finger pulps and recovered the superficial sensation and tactile sense of finger pulps. The two point discrimination on average was 5.00 mm+/-0.23 mm in Group A and 6.00 mm+/-0.30 mm in Group B. The difference between two groups was highly significant. Nine months later, their senses of finger pulps between two groups were recovered basically. CONCLUSIONS: The reversed fasciocutaneous island flap from the same finger is the first choice to reconstruct the finger pulp defect, and the anastomosis of dorsal branch of the digital nerve shall be determined according to the specific condition.