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Notes: We compared ropivacaine 0.75% and bupivacaine 0.5% for extending low-dose epidural analgesia for emergency Caesarean section, using a prospective double-blind randomised controlled trial design. The trial was halted after 45 patients were studied (23 ropivacaine; 22 bupivacaine) because bupivacaine was replaced by levobupivacaine in our unit. Time to reach T4 for loss of cold sensation was similar in both groups, although analgesic supplementation was required less often in the ropivacaine group than in the bupivacaine group (2/23 vs. 9/21; p = 0.01).

Notes: Twenty-four inexperienced participants were timed inserting the intubating laryngeal mask airway and the laryngeal mask airway in 75 anaesthetised subjects. Adequacy of ventilation was assessed on a three-point scale. The pressure at which a leak first developed around the device's cuff was also measured. There was no significant difference in insertion time or the likelihood of achieving adequate ventilation between devices. However, the intubating laryngeal mask airway was better at providing adequate ventilation without audible leak (58/75 (77%) vs. 42/75 (56%); p = 0.009). The median (range [IQR]) pressure at which an audible leak developed was higher for the intubating laryngeal mask airway, 34.5 (14–40 [29–40]) cmH2O, than for the laryngeal mask airway, 27.5 (14–40 [22–33]) cmH2O (p 〈 0.001). The intubating laryngeal mask airway is worthy of further consideration as a tool for emergency airway management for inexperienced personnel.

Notes: Diffusivities of pseudoplanar molecules at trace concentration in methanol have been measured at 298.2 K using Taylor's dispersion method. The data of the polar and nonpolar aromatic solutes are compared, and the effects due to solute–solvent interactions on diffusion, together with the solvation numbers, are determined. In this study, the effects are combined with the recently developed solute hydrogen-bond scales to unravel hydrogen bonding between solute and solvent. It is found that the degrees of association of the solutes with methanol decrease in the sequence hydroquinone〉aromatic acids〉phenols〉aromatic amines〉aprotic aromatic compounds. Except for o-nitrophenol, which is capable of intramolecular hydrogen bonding, all aromatic acids, phenols, and amines studied behave more as hydrogen-bond donor than acceptor in methanol. The present work also indicates that motions of associated molecules can be understood in terms of the molecular behavior of nonassociated solutes and the hydrogen-bond acidity/basicity of polar solutes. © 1999 American Institute of Physics.

Notes: Limiting mutual diffusion coefficients of aromatic compounds in acetone have been measured at 298.2 K by using the chromatographic peak-broadening method. The data of the polar and nonpolar pseudoplanar solutes are compared, and the effects of molecular association on diffusion as well as the solvation numbers are determined. It is found that the effects of hydrogen bonding are such that –OH〉–NH2〉–SH, and that the solvation numbers are approximately equal for solutes containing the same polar group. Using ab initio molecular orbital theory, molecular solute–acetone interaction energies have been calculated. There exists a nearly linear relationship between the interaction energy and the effect of solute–solvent association on diffusion. The applicability of the rough-hard-sphere theory to the diffusion of associated molecules is discussed. © 1997 American Institute of Physics.

Notes: Summary. About half of the haemophiliacs in Hong Kong have been infected by human immunodeficiency virus (HIV). This study aimed to determine their clinical course of progression. Forty-seven adult patients with congenital coagulation factor deficiency being followed up regularly from January 1992 onward in the Department of Medicine of Queen Mary Hospital, Hong Kong, were included in this study. Twenty were positive for HIV antibody and the remaining 27 were negative. Three other HIV-positive patients who died before 1992 were excluded. From January 1992 to June 1996, the 47 patients included in the study were followed up in the clinic every 3–6 months with regular CD4, CD8 lymphocyte counts and β2 microglobulin levels. At the initiation of the study in January 1992, the HIV-infected patients had already a lower mean CD4 count (360.4 μL−1 versus 658.8 μL−1, P〈0.01), a reversed CD4/CD8 ratio (0.53) and a higher mean serum β2 microglobulin level (1.853 μg mL−1 versus 1.315 μg mL−1, P〉0.05). On regular follow-up, HIV-positive patients had a more significant progressive fall in their mean CD4 count (301.6 μL−1 versus 360.4 μL−1, P〈0.01) and rise in their mean serum β2 microglobulin level (2.60 μg mL−1, versus 1.853 μg mL−1, P〈0.05). The CD4 and CD8 counts of HIV-positive patients were falling at a rate of 1.44 μL−1 month−1 and 4.03 μL−1 month−1 respectively. During the follow-up period, two of the 20 HIV-positive patients developed clinical acquired immunodeficiency syndrome (AIDS) at 15 and 36 months from the initiation of the study. Both patients had typical features of AIDS with a low CD4 count, reversed CD4/CD8 ratio and elevated β2 microglobulin level. The former patient eventually died of fungal brain abscess. The remaining 18 HIV-positive patients so far remained clinically asymptomatic. Eleven patients were put on antiretroviral drug therapy when their CD4 counts fell below 200 μL−1. Only two of the 20 HIV-infected patients developed AIDS during the observation period of 4 years; this figure of 10% is relatively slow. Two of our patients died of AIDS before the study was initiated in 1992. Even if they were included, still only 17.4% had progressed. The figure is in the lowest rate of progression expected from Western experience. Although our study population is small, it remains unclear why our HIV-infected Chinese haemophiliacs have a slow rate of progression to AIDS.

Notes: SUMMARY: We report a case of a 35-year-old man with autosomal dominant polycystic kidney disease (ADPKD) who presented for the first time with end-stage renal failure. He had a long history of blurred vision and on examination had retinitis pigmentosa. to our knowledge, this is the second report on the association of retinitis pigmentosa with polycystic kidney disease.

Notes: This paper studies the effects of load sequence and interaction, and overloading effect on the fatigue damage of bridges on the basis of a non-linear fatigue damage model. The model is derived from the theory of continuum damage mechanics for high-cycle fatigue. Fatigue behaviour at two levels of constant stress range is first discussed in detail. The formulation for the effective fatigue strength of the predamaged members is then derived, and the results predicted by the model are compared with the experimental data for two stress level tests and other results obtained from linear and double linear fatigue damage models. The variation of cycle ratio and fatigue life due to overloading is secondly investigated; the equations for evaluating the effect of overloading on fatigue damage accumulation on bridges at normal traffic loading are then derived. It has been demonstrated that the developed model can well describe the effect of load sequence and interaction and has also been verified by comparing the predicted results obtained by the model with the experimental data based on two levels of stress tests. The effect of accidental overloading on the fatigue damage of existing bridges can also be evaluated using the model. The model is applied to evaluate the fatigue damage and service life of the Tsing Ma Bridge, an essential portion of the transport network for the Hong Kong airport, under normal traffic loading and possible accidental overloading.