Jt Steen

Human resource strategies and organisational structures for managing gold‐collar workers

States that the rapid expansion of the information technology (IT) industry has brought about skill shortages in many advanced western economies. Examines human resource (HR) policies and organisational structures for developing and retaining IT staff through two case studies of organisations in the IT and telecommunications sector in Australia. Concludes that developing HR policies in order to recruit and retain staff, and linking these to appropriate organisational structure, is becoming of increased importance in order to encourage employees to remain with a company.

Relationship of MTT reduction to stimulants of muscle metabolism.

MTT, a positively charged tetrazolium salt, is widely used as an indicator of cell viability and metabolism and has potential for histochemical identification of tissue regions of hypermetabolism. In the present study, MTT was infused in the constant-flow perfused rat hindlimb to assess the effect of various agents and particularly vasoconstrictors that increase muscle metabolism. Reduction of MTT to the insoluble formazan in muscles assessed at the end of experiments was linear over a 30 min period and production rates were greater in red fibre types than white fibre types. The vasoconstrictors, norepinephrine (100 nM) and angiotensin (10 nM) decreased MTT formazan production in all muscles but increased hindlimb oxygen uptake and lactate efflux. Veratridine, a Na(+) channel opener that increases hindlimb oxygen uptake and lactate efflux without increases in perfusion pressure, also decreased MTT formazan production. Membrane stabilizing doses (100 microM) of (+/-)-propranolol reversed the inhibitory effects of angiotensin and veratridine on MTT formazan production. Muscle contractions elicited by stimulation of the sciatic nerve, reversed the norepinephrine-mediated inhibitory effects on MTT formazan production, even though oxygen consumption and lactate efflux were further stimulated. Stimulation of hindlimb muscle oxygen uptake by pentachlorophenol, a mitochondrial uncoupler, was not associated with alterations in MTT formazan production. It is concluded that apart from muscle contractions MTT formazan production does not increase with increased muscle metabolism. Since the vasoconstrictors angiotensin and norepinephrine as well as veratridine activate Na(+) channels and the Na(+)/K(+) pump, energy required for Na(+) pumping may be required for MTT reduction. It is unlikely that vasoconstrictors that stimulate oxygen uptake do so by uncoupling respiration.

Purine and pyrimidine nucleotide metabolism of vascular smooth muscle cells in culture

1. Cultures of vascular smooth muscle cells accumulate extracellular breakdown products of purine and pyrimidine nucleotides that, over 9 hr, represent 60 +/- 7 and 78 +/- 17%, respectively, of the intracellular nucleotide content. 2. The accumulation is stimulated during contracture with 20 mM KCl or 70 microM carbachol, consistent with the notion that both pyrimidine and purine nucleotides are involved in the energetics of smooth muscle contracture. 3. Because the intracellular levels of pyrimidine and purine nucleotides remain constant, it appears likely that rates of synthesis match the rates of release. 4. Ectonucleotidases are present that can degrade ATP, UTP, and CTP. High-energy nucleotides may be the primary products released.

Vasoconstrictor-mediated release of purines and pyrimidines from perfused rat hindlimb, perfused mesenteric arcade and incubated de-endothelialized aorta

1. Reperfusion of hindlimbs that had previously been exposed to either 10 or 60 min global ischaemia resulted in transient washouts of uracil and uric acid in approximate proportion to the interval of ischaemia. However, changing the interval of sequential angiotensin II infusions from 10 to 60 min did not affect the magnitude of sustained uracil and uric acid release. 2. Perfused rat mesenteric artery arcade released uracil and uric acid and each was further increased approximately 2-fold by exposure to the vasoconstrictor, serotonin (6.7 microM). 3. Incubated de-endothelialized rat aorta also released purines and pyrimidines and this was increased further when subjected to increased work loads. 4. The increased rates of release of purines and pyrimidines from hindlimb, and the simpler vascular preparations of mesenteric arcade and aorta, were in proportion to the relative rates of increase in oxygen consumption under maximum vascular load. 5. It is concluded that the release of purine and pyrimidine nucleosides and their catabolites from perfused rat hindlimb occurring as a consequence of vasoconstriction is not the result of release from previously ischaemic tissue. In addition, release of purines and pyrimidines appears to be a general feature of vascular smooth muscle subjected to high workloads.