Haemodynamic changes and heart rate variability during midazolam-propofol co-induction.

In a prospective, blind, randomised study, we examined the effects of midazolam-propofol co-induction on haemodynamic (blood pressure, heart rate and stroke volume) and heart rate variability. The latter was measured by spectral analysis using the maximum-entropy method to calculate the following: the low frequency component (LF), which reflects both the cardiac sympathetic and parasympathetic activity, the high frequency component (HF) and entropy, which reflects the cardiac parasympathetic activity, the total power (TP), calculated by the addition of LF and HF, and the LF/HF ratio, which reflects the balance between the cardiac sympathetic and parasympathetic nervous activity. Forty patients were randomly allocated to the propofol group and the midazolam-propofol group, and the parameters described above were calculated at baseline (T1), post induction (T2), after tracheal intubation (T3), and 3 min (T4) and 5 min after intubation (T5). Propofol was administered at 2.5 mg.kg(-1) in the propofol group and midazolam at 0.1 mg.kg(-1) followed by propofol at 1.5 mg.kg(-1) in the midazolam-propofol group for anaesthesia induction. Then, propofol was administered at 4-6 mg.kg(-1)propofol for maintenance in both groups. The midazolam-propofol group showed compensated haemodynamic changes, which were related to significant increases in the LF/HF ratio at T2, T4 and T5 (p = 0.011, 0.038 and 0.034). These results suggest that the midazolam-propofol combination yielded compensated modulatory effects on the cardiovascular system, including preserved baroreflex activity.

Purification and characterization of NADPH-dependent aldo-keto reductase specific for beta-keto esters from Penicillium citrinum, and production of methyl (S)-4-bromo-3-hydroxybutyrate.

A novel beta-keto ester reductase (KER) was purified to homogeneity from recombinant Escherichia coli (pTrcKER) cells, which efficiently expressed the ker gene cloned from Penicillium citrinum IFO4631. The enzyme was monomeric and had a molecular mass of 37 kDa. It catalyzed the reduction of some beta-keto esters, especially alkyl 4-halo-3-oxobutyrates. However, it did not catalyze the reverse reaction, the dehydrogenation of alkyl 4-halo-3-hydroxybutyrates and other alcohols. The enzyme required NADPH as a cofactor and showed no activity with NADH. Therefore, it was defined as a NADPH-dependent aldo-keto reductase (AKR3E1), belonging to the AKR superfamily. The enzyme stereospecifically produced methyl (S)-4-bromo-3-hydroxybutyrate from its keto derivative with high stereospecificity (97.9% enantiomer excess). E. coli cells expressing KER and glucose dehydrogenase in the water/butyl acetate two-phase system achieved a high productivity of (S)-4-bromo-3-hydroxybutyrate (277 mM, 54 mg/ml) in the organic solvent layer.

Growth factor expression in the osteophytes of the human femoral head in osteoarthritis.

Osteoarthritis is characterized by marked osteophyte formation consisting of new cartilage and bone. Because several growth factors are known to be involved in chondrogenesis and osteogenesis, the expression of transforming growth factor-beta 1 and basic fibroblast growth factor in the osteophytes of the human femoral heads in osteoarthritis were examined. Transforming growth factor-beta 1 messenger ribonucleic acid was detected in the osteophytes by reverse transcription-polymerase chain reaction. All of the nine examined osteophytes expressed transforming growth factor-beta 1 messenger ribonucleic acid, whereas one of four osteoarthritic femoral heads and none of four osteonecrotic femoral heads expressed transforming growth factor-beta 1 messenger ribonucleic acid. The extent of transforming growth factor-beta 1 messenger ribonucleic acid expression varied among the osteophytes. Transforming growth factor-beta 1 or basic fibroblast growth factor was analyzed in osteophytes immunohistochemically. Transforming growth factor-beta 1 was localized in the superficial cells in the osteophyte cartilage, but it was scarcely detected in the superficial cells in the degenerative articular cartilage. Basic fibroblast growth factor was detected in the cells in the whole layer of osteophyte cartilage and in the articular cartilage. There was a difference in the localization, which suggests the different roles of transforming growth factor-beta 1 and basic fibroblast growth factor in bone and cartilage metabolism in osteophyte formation.

Neuregulin receptor-mediated gene transfer by human epidermal growth factor receptor 2-targeted antibodies and neuregulin-1.

The human epidermal growth factor receptors 2, 3, and 4 (HER2, HER3, and HER4, respectively) are frequently overexpressed in many human cancers, and therefore may be potential targets for receptor-mediated gene transfer. To evaluate this possibility, we constructed a series of HER-targeted gene transfer vehicles by covalently linking poly-L-lysine polymers (pLYS) to the epidermal growth factor-like domain of the HER ligand neuregulin-1 (NRG1(177-244)), a HER2 antibody (Ab), and the Fab fragment of the HER2 Ab. In vitro, pLYS modification of NRG1(177-244) decreased the affinity of the ligand for HER3 or HER4 homodimer receptors by 6- to 7-fold. DNA loading of the pLYS-modified NRG1(177-244) had a minimal additional affect on the affinity of the complex for its receptor. In cell lines engineered to solely express HER2, HER3, or HER4, each vehicle correctly targeted the receptors; the NRG1(177-244) construct transferred a luciferase gene only into cells expressing HER4, whereas the HER2 Ab and Fab constructs transferred the reporter gene only into cells expressing HER2. The most efficient gene transfer occurred using the intact HER2 Ab as a gene transfer vehicle, whereas the Fab fragment of the HER2 Ab was the least efficient, and NRG1(177-244) was intermediate. These studies suggest that the NRG receptor or HER2, a component of the receptor, can be pursued as targets for gene transfer.

Thyroid hormone-induced chondrocyte terminal differentiation in rat femur organ culture.

Thyroid hormone plays a role in skeletal maturation. The present study was undertaken to investigate the effect of thyroid hormone on growth and maturation of the epiphyseal cartilage in the rat femur organ culture system. The femora increased in both weight and size over time in culture in the absence of serum. The growth rate was suppressed by thyroxine treatment. Thyroxine induced chondrocyte hypertrophy in the area adjacent to the articular surface in the femoral condyle. In this area, the expression of type X collagen, a marker of chondrocyte terminal differentiation, was detected after 21 days in culture by immunohistochemistry and reverse transcription/polymerase chain reaction. These data suggest that thyroxine suppresses cartilage growth by stimulating chondrocyte terminal differentiation.

Do superoxide radicals in blood indicate anastomotic patency after microvascular tissue reperfusion?

Superoxide radicals were measured in the blood of six patients who underwent vascular reconstruction after ischemic injury in an attempt to predict prognosis following surgery. Three free-tissue transfers (two free latissimus dorsi flaps, one free vascularized fibular osteocutaneous graft) were performed on patients with skin or bone defects associated with open tibial fractures. Vascular reconstructions were performed on two patients with popliteal vascular injuries, in one case with an open femoral fracture and in another with an open knee dislocation. A third vascular reconstruction was performed on a patient with a subclavian artery injury associated with a clavicular fracture. Superoxide levels in the blood were quantified by a chemiluminescence method using a derivative of luciferin. Blood was obtained prior to reperfusion and periodically to 72 hr postoperatively. In patients who underwent successful reconstructions, superoxide levels increased after reperfusion. Vascular insufficiency was associated with acute drops in superoxide concentrations. Superoxide levels are a promising clinical marker which can predict insufficiency during reperfusion following tissue ischemia.