ABSTRACT
Holas and March [Phys. Rev. A. 51, 2040 (1995)] gave a formally exact theory for the exchange-correlation (xc) force F(xc)(r)= -inverted Deltaupsilon(xc)(r) associated with the xc potential upsilon(xc)(r) of the density-functional theory in terms of low-order density matrices. This is shown in the present study to lead, rather directly, to the determination of a sum rule nF(xc)=0 relating the xc force with the ground-state density n(r). Some connection is also made with an earlier result relating to the external potential by Levy and Perdew [Phys. Rev. A. 32, 2010 (1985)] and with the quite recent study of Joubert [J. Chem. Phys. 119, 1916 (2003)] relating to the separation of the exchange and correlation contributions.
Subject(s)
Chemistry, Physical/methods , Proteins/chemistry , Absorption , Electrons , Kinetics , Models, Statistical , Models, Theoretical , Research Design , Static Electricity , Stress, MechanicalABSTRACT
We performed a prospective, randomized study comparing the efficacy and safety of remifentanil, propofol or both for conscious sedation during eye surgery under retrobulbar blockade. Forty-five unpremedicated patients were assigned to receive remifentanil (group R) (n = 15, mean dosage: 0.05 +/- 0.03 microgram kg-1 min-1), propofol (group P) (n = 15, 1.5 +/- 0.5 mg kg-1 h-1) or a combination (group RP) (n = 15, R: 0.03 +/- 0.01 microgram kg-1 min-1; P: 0.7 +/- 0.2 mg kg-1 h-1). Haemodynamic responses were comparable among all groups. Minimum values for respiratory rate were lower in R patients (R: 7 vs. P and RP: 10 breaths min-1). Perioperative blood gas analysis showed differences in maximum carbon dioxide tensions (R: 51.5 vs. P: 48.3 vs. RP: 45.5 mmHg) and decrease in minimum pH values (R: -0.06 vs. P: -0.0 vs. RP: -0.01). All group P patients reported mild to intense pain during retrobulbar block, while 53% of the group R patients were free from pain. In group RP, 60% of patients experienced no pain and the remaining 40% reported mild pain only. Remifentanil, applied as the sole agent, provided superior pain relief and patient comfort when compared with propofol, but produced greater respiratory depression and postoperative nausea. The combination of remifentanil and propofol provided haemodynamic stability, adequate spontaneous respiration and pain relief, with a low risk of untoward side effects.
Subject(s)
Anesthesia, Conduction , Anesthetics, Intravenous , Conscious Sedation , Ophthalmologic Surgical Procedures , Piperidines , Propofol , Adult , Aged , Anesthesia, Conduction/adverse effects , Anesthetics, Intravenous/adverse effects , Conscious Sedation/adverse effects , Female , Hemodynamics/drug effects , Humans , Male , Middle Aged , Oxygen/blood , Pain/prevention & control , Pain Measurement/drug effects , Piperidines/adverse effects , Propofol/adverse effects , Prospective Studies , Remifentanil , Respiratory Mechanics/drug effectsABSTRACT
Among 460 children who had an orchiopexy (ORP), we identified 72 children who had attended our institution 1-12 years earlier and in whom the testicular position had been specified. Of the 72 boys 19 were had ascended testes (26%). The age at ORP of the children with ascent of the testes was 7.0 years (1.8-14.0 years). Light and electron microscopy of 13 testicular biopsies taken at ORP, showed alterations of germ cells and Sertoli cells, similar but less pronounced than alterations seen in congenital undescended testes. Conclusion. A normally positioned testis may ascend into the inguinal region or upper scrotum and remain there fixed. This secondary cryptorchidism does not usually respond to human chorionic gonadotropin treatment and must be corrected by orchiopexy.
Subject(s)
Cryptorchidism/physiopathology , Testis/physiopathology , Adolescent , Child , Child, Preschool , Cryptorchidism/pathology , Cryptorchidism/surgery , Humans , Infant , MaleABSTRACT
This prospective study was designed to evaluate the sedative effect of two different anaesthetic drugs in patients undergoing ophthalmic surgery. Propofol is an intravenous hypnotic agent with a short half-life of about 30 min. A constant high oxygen saturation in continuous pulse oximetry was achieved in previous studies using propofol for sedation. Furthermore, an IOP-lowering effect was proved. Propofol was compared to diazepam, a well-established sedative, which has been used for many years for sedation of patients in local anaesthesia. METHOD. One hundred patients of comparable anaesthesiologic risk (ASA classes 2-4) undergoing identical surgical procedures received either propofol (n = 50), or diazepam (n = 50). Propofol was infused at a rate of 0.8-3.0 mg/kg/h, while diazepam was given as a slow intravenous bolus of 5 mg before surgery. All patients were monitored by continuous pulse oximetry. RESULTS. Oxygen saturation of patients receiving propofol was never less than 96%. In contrast, oxygen saturation of patients sedated by diazepam dropped to 85%, especially for the first 5 min following administration, before improving to 95% during the next 10 min. None of the patients who received propofol showed signs of motor unrest, a great handicap in ophthalmic surgery, while four patients who received diazepam were restless enough to hamper the procedure. None of the patients who received propofol developed respiratory depression. In contrast, marked respiratory depression, motor agitation, and postoperative fatigue slowing mobilization were common in patients who received diazepam.