Is being a doctor still fun?

Over the past two decades, a decline in physician job and career satisfaction has been reported. This study was developed to determine the current state of physician satisfaction and to define factors correlated with overall satisfaction. We mailed a survey to 406 physicians in Solano County, California. Responses were anonymous, and data were analyzed by several methods. Of the 406 physicians, 251 (62%) responded. Most respondents were satisfied with their jobs (80%). The vast majority felt good about their ability to help their patients (92%), enjoyed the relationships they had with patients (93%) and colleagues (86%), and found their work intellectually satisfying (89%). Nearly two thirds (63%) of respondents thought their job was "fun." This ability to derive great pleasure from work showed the strongest correlation with overall satisfaction. Overall satisfaction did not differ between primary care and non-primary care physicians or between physicians in a large health maintenance organization and those in mostly solo and small-group fee-for-service practices. Despite substantial challenges to physician morale and autonomy, most responding physicians in our study continued to enjoy overall job satisfaction, and a solid majority thought that their work was fun.     

Chromosomal mapping of murine c-fes and c-src genes.

The murine homologs of two viral oncogenes associated with tyrosine-specific kinase activity have been assigned to different loci in the mouse genome. The segregation of restriction site polymorphisms, as detected by probes that are specific for endogenous c-fes and c-src sequences, was followed in the DNA of recombinant inbred strains. The c-fes gene was mapped to the proximal portion of chromosome 7, very close to the Gpi-1 locus, whereas c-src was linked to the Psp locus on the distal half of chromosome 2.     

The decomposition of branch-wood in the canopy and floor of a mixed deciduous woodland

Summary The pattern of decomposition of branch-wood greater than 2 cm diameter is described for a one hectare site at Meathop Wood, Cumbria, based on studies carried out as part of the IBP between 1967 and 1972. Three phases of decomposition are recognised. Following the death of branches in the canopy and their colonisation by fungi, decomposition proceeded at an average annual loss rate of about 8.4%. Wood at branch-fall had on average lost about 40% of its original dry weight. On the forest floor the average annual rate of weight lost to decomposition was 17.1%. This could be divided into two phases; fungi were predominant initially but shortly after branch-fall invasion by wood-boring animals occurred. The average annual branch-fall between 1967 and 1971 was 31.5 g·m^-2. The standing crop of dead branch-wood on the forest floor was estimated in 1971 to be 203.3 g·m^-2. Assuming steady state this implies an annual turnover of 15.5% of the standing crop which is in good agreement with the observed decomposition rate.Considerable differences in the rates of decay were observed between individual branches. No significant differences were found between branches of the four main species of tree investigated (Quercus robur pluspetraea, Fraxinus excelsior, Betula pendula pluspubescens, Corylus avellana).     

A strain difference in the daily rhythm of glyceraldehyde-3-phosphate dehydrogenase activity in the mouse

Summary A/J mice differ from C57BL/6J mice in the time of the daily peak of activity of glyceraldehyde-3-phosphate dehydrogenase (GAPD) in thymus and in thyroid. Diurnal rhythms in several other enzymes, and indeed of GAPD in tissues other than thymus and thyroid, were identical in the two strains. The A/J characteristic is dominant, and the trait shows neither X-linked nor Y-linked inheritance.     

The Emerging Role of Copeptin

Direct measurement of the nonapeptide vasopressin has been limited by analyte instability ex vivo and in vivo rapid degradation, low serum concentrations requiring a sensitive assay and inherent secretory pulsatility. Copeptin is a 39 amino acid glycopeptide cleavage product of vasopressin synthesis with high stability, providing a marker of vasopressin secretion. Copeptin measurement has applications in diagnosis of diabetes insipidus and other diseases with altered vasopressin secretion. This review summarises our current understanding of serum copeptin measurement in diabetes insipidus and possible future applications of copeptin assays. As vasopressin is a stress hormone, there is emerging evidence on the use of copeptin for diagnosis and prognostication of disorders such as syndrome of inappropriate anti-diuretic hormone secretion, diabetes mellitus, critical illness, stroke, cardiovascular disease, respiratory disease, renal disease and thermal stress. Copeptin concentration measurement is likely to improve the diagnostic reliability of diabetes insipidus and, as a marker of stress, may have diagnostic or prognostic utility in specific clinical circumstances. Further studies are needed to determine if goal-directed therapy using plasma copeptin concentrations may improve patient outcomes.     

Effect of gestational stage on uterine artery blood flow during exercise in rabbits.

We tested the hypothesis that the uterine artery vasoconstrictor response to graded exercise during early gestation would be similar to the nonpregnant (NP) state and would be attenuated at mid and term gestation. Responses to graded treadmill exercise were measured in six female New Zealand White rabbits in the NP state and at day 10, day 20, and day 28 (term) of gestation. Uterine artery blood flow (UtBF) was measured continuously with a Transonic flow probe. Rabbits performed a graded exercise test to voluntary exhaustion (maximal exercise) starting at 7 m/min, 7% grade. UtBF and uterine artery conductance (UtC) decreased similarly during graded exercise (P < 0.01) in the NP state [at maximal exercise: -40% (SD 20) for UtBF and -45% (SD 14) for UtC] and at day 10 of gestation [at maximal exercise: -48% (SD 17) for UtBF; -56% (SD 14) for UtC]. In contrast, there was little change in UtBF or UtC during graded exercise at day 20 [at maximal exercise: -4% (SD 17) for UtBF, P < 0.05 vs. NP; -16% (SD 12) for UtC, P < 0.01 vs. NP] and at day 28 [At maximal exercise: +7% (SD 15) for UtBF, P < 0.01 vs. NP; -2% (SD 24) for UtC, P < 0.01 vs. NP], indicating substantial attenuation of the uterine artery vasoconstrictor response to exercise. At rest, UtC responses to graded doses of intravenous phenylephrine were unaffected by the stage of gestation, which suggests that uterine artery responsiveness to alpha(1)-adrenoreceptor stimulation is preserved through gestation. Normal pregnancy in the rabbit is associated with attenuation of the uterine artery vasoconstrictor response to graded exercise that develops by mid gestation.     

Expression, purification, and physical characterization of Escherichia coli lipoyl(octanoyl)transferase

Lipoic acid is a sulfur-containing 8-carbon fatty acid that functions as a central cofactor in multienzyme complexes that are involved in the oxidative decarboxylation of glycine and several alpha-keto acids. In its functional form, it is bound covalently in an amide linkage to the epsilon-amino group of a conserved lysine residue of the "lipoyl bearing subunit," resulting in a long "swinging arm" that shuttles intermediates among the requisite active sites. In Escherichia coli and many other organisms, the lipoyl cofactor can be synthesized endogenously. The 8-carbon fatty-acyl chain is constructed via the type II fatty acid biosynthetic pathway as an appendage to the acyl carrier protein (ACP). Lipoyl(octanoyl)transferase (LipB) transfers the octanoyl chain from ACP to the target lysine acceptor, generating the substrate for lipoyl synthase (LS), which subsequently catalyzes insertion of both sulfur atoms into the C-6 and C-8 positions of the octanoyl chain. In this study, we present a three-step isolation procedure that results in a 14-fold purification of LipB to >95% homogeneity in an overall yield of 25%. We also show that the protein catalyzes the transfer of the octanoyl group from octanoyl-ACP to apo-H protein, which is the lipoyl bearing subunit of the glycine cleavage system. The specific activity of the purified protein is 0.541 U mg(-1), indicating a turnover number of approximately 0.2 s(-1), and the apparent Km values for octanoyl-ACP and apo-H protein are 10.2+/-4.4 and 13.2+/-2.9 microM, respectively.