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Impregnation of phosphine-decorated styrene-based polymer immobilized ionic liquid (PPh2-PIIL) with ruthenium(iii) trichloride resulted in facile reduction of the ruthenium to afford Ru(ii)-impregnated phosphine oxide-decorated PIIL (OPPh2PIIL). The derived phosphine oxide-decorated polymer immobilized ionic liquid-stabilized RuNPs (RuNP@OPPh2-PIILS) catalyse the highly efficient and selective aqueous phase reduction of the carbonyl group in aryl and heteroaryl ketones and aldehydes, including furfural, as well as the hydrogenation of levulinic acid and its ethyl ester to afford γ-valerolactone (GVL). While this is the first report of RuNPs stabilized by a phosphine oxide-modified support, there appear to be several recent examples of similar serendipitous oxidations during the synthesis of RuNPs by impregnation of a phosphine-decorated polymer with ruthenium trichloride; as these were either misinterpreted or not recognised as such we have carried out a detailed characterization and evaluation of this system. Reassuringly, RuNP@OPPh2-PIILS generated from phosphine oxide-decorated polymer immobilized ionic liquid (OPPh2-PIIL) impregnated with ruthenium trichloride is as efficient as that prepared directly from RuCl3and PPh2-PIIL. Incorporation of PEG into the polymer support improved catalyst performance and the initial TOF of 2350 h−1obtained for the aqueous phase hydrogenation of acetophenone is among the highest to be reported for a ruthenium nanoparticle-based catalyst. Under optimum conditions, RuNP@OPPh2-PEGPIILS recycled ten times with only a minor reduction in activity and no detectable change in selectivity. High yields and excellent selectivities were also obtained for hydrogenation of the CO across a range of substituted aryl and heteroaryl ketones. Complete hydrogenation of the aromatic ring and CO could also be achieved by increasing the pressure and temperature accordingly. The same system also catalyzes the aqueous phase hydrogenation of furfural under mild conditions with an initial TOF of 3160 h−1as well as the selective hydrogenation of levulinic acid and its ethyl ester to γ-valerolactone (GVL); reaction times for the latter could be reduced quite significantly by addition of either butyric acid or Amberlyst H-15.

With Careful Attention To Materials And Construction, Resistors Can Achieve Continuous Power Ratings Of 250 W/in [2]. In Hybrid Designs. The electronics industry is continuously searching for ways to reduce […]

(JAMA. 2021;326:2478–2487)Continuous positive airway pressure (CPAP) is recommended for newly born preterm infants. A previous meta-analysis of clinical trials compared CPAP to intubation and ventilation in terms of death or bronchopulmonary dysplasia and found CPAP had a relative risk of 0.91 [95% confidence interval (CI), 0.84-0.99]. In the studies used in meta-analysis, exogenous surfactant was administered only to infants with relatively high levels of inspired oxygen. This study, the OPTIMIST-A trial aimed to determine whether minimally invasive surfactant therapy, using a thin catheter, would lower the incidence of death and/or bronchopulmonary dysplasia.

The Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial compared the use of eptifibatide with placebo in 2064 coronary intervention patients. It was previously reported that Canadian patients had reduced rates of 30-day and one-year death, myocardial infarction (MI) or targetvessel revascularization (TVR) compared with patients in the United States (US).

Loss of CD4+T cells in the gut is necessary but not sufficient to cause AIDS in animal models, raising the possibility that a differential loss of CD4+T-cell subtypes may be important. We found that CD4+T cells that produce interleukin (IL)-17, a recently identified lineage of effector CD4+T-helper cells, are infected by SIVmac251in vitro and in vivo, and are found at lower frequency at mucosal and systemic sites within a few weeks from infection. In highly viremic animals, Th1 cells predominates over Th17 T cells and the frequency of Th17 cells at mucosal sites is negatively correlated with plasma virus level. Because Th17 cells play a central role in innate and adaptive immune response to extracellular bacteria, our finding may explain the chronic enteropathy in human immunodeficiency virus (HIV) infection. Thus, therapeutic approaches that reconstitute an adequate balance between Th1 and Th17 may be beneficial in the treatment of HIV infection.Mucosal Immunology (2008) 1, 279–288; doi:10.1038/mi.2008.14; published online 7 May 2008

The platelet glycoprotein (GP) IIb/IIIa integrin plays a key role in mediating platelet aggregation. Blockade of the platelet GP IIb/IIIa receptor prevents arterial thrombosis in animal models much better than does aspirin. Among the most specific inhibitors in this class of drugs is eptifibatide (IntegrilinTMMillennium Pharmaceuticals, Inc.), a cyclic heptapeptide based on a peptide recognition sequence found in snake venom. Peptide inhibitors, such as eptifibatide, bind competitively to GP IIb/IIIa and have a short half-life, allowing the effect to be rapidly reversible and providing a favourable overall safety profile. Eptifibatide has been studied in a broad range of ischaemic coronary conditions including percutaneous coronary intervention (PCI), ST-segment and non-ST-segment acute myocardial infarction (MI) and unstable angina. In PCI and non-ST-segment MI, therapy with eptifibatide has been shown to reduce acute ischaemic complications without any increased risk of life-threatening adverse events. In the recently reported Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial, two 180 μg/kg boluses of eptifibatide, 10 min apart, followed by an 18 – 24 h infusion at 2 μg/kg/min given as adjunctive therapy in non-urgent PCI reduced the 30-day composite of death, MI and need for urgent target vessel revascularisation from 10.4 to 6.8% compared with placebo. These results were achieved under conditions of typical contemporary PCI, namely the implantation of second- and third-generation stents deployed at high balloon pressures along with modern adjunctive pharmacological treatment, particularly the universal use of thienopyridines and lower-dose heparin. Few significant pharmacological effects other than inhibition of platelet aggregation and the effect on bleeding time have been reported. Future research will focus on alternative clinical applications and combinations with other therapies to further improve cardiovascular outcomes.

While treatment guidelines have been developed to guide the management of Staphylococcus aureus bacteraemia, there is a need to validate these guidelines in different clinical settings and to relate the effect of compliance to clinical outcome. To assess the impact of adherence to treatment guidelines on clinical outcome and to explore the role of transoesophageal echocardiography (TOE) in risk stratification.We undertook a 2-year mixed retrospective and prospective study of all cases of S. aureus bacteraemia at Fremantle Hospital, documenting the clinical and microbiological features of each case, the results of echocardiography, adherence with published clinical guidelines and clinical outcome. Failure to comply with guidelines was observed in 41% (38 of 93) of cases, the majority receiving abbreviated treatment. An increased rate of relapse was observed among patients who received inadequate therapy (5/38 vs 1/55; P = 0.04). Ten of 28 eligible patients underwent TOE and the test led to significant changes in management in two of those cases. While non-adherence with clinical guidelines was associated with an increased risk of relapse, the role of TOE in risk stratification was limited by factors including cost, limited acceptance of the test and the need for prolonged therapy for other indications. (Intern Med J 2002; 32: 224−232)

Jak3 is responsible for growth signals by various cytokines such as interleukin (IL)-2, IL-4, and IL-7 through association with the common gamma chain (gammac) in lymphocytes. We found that T cells from Jak3-deficient mice exhibit impairment of not only cytokine signaling but also early activation signals and that Jak3 is phosphorylated upon T cell receptor (TCR) stimulation. TCR-mediated phosphorylation of Jak3 is independent of IL-2 receptor/gammac but is dependent on Lck and ZAP-70. Jak3 was found to be assembled with the TCR complex, particularly through direct association with CD3zeta via its JH4 region, which is a different region from that for gammac association. These results suggest that Jak3 plays a role not only in cell growth but also in T cell activation and represents cross-talk of a signaling molecule between TCR and growth signals.

One assumption of the immunocompetence handicap hypothesis is that androgens increase the expression of secondary sex characters while concomitantly suppressing immune function. Primary sex function, such as spermatogenesis, may also benefit from immune down-regulation since spermatozoa are not recognised as self by the immune system. Males with greater parasite resistance should therefore be able to experience higher androgens levels with a resultant increase in spermatogenic investment and ejaculate quality, plus greater suppression of the immune system. We investigate this possibility in two species of Australian bat. Testis size was used as a measure of ejaculate investment and quality, and spleen size was used as an indicator of immune function. Significant negative relationships were found between spleen and testis mass in one species and a negative trend was noted in a second. When the overall effect size was calculated, the negative association across both species was statistically significant. Our results are consistent with the immunocompetence handicap hypothesis since males able to withstand greater immune system down-regulation had larger testes.

Intermolecular hydrogen-bonding in thick films of isonicotinic acid evaporated onto rutile TiO2(110) has been investigated with X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The rate of deposition is found to be a key factor in overcoming the kinetic barriers to extensive hydrogen-bond formation, which, when present, gives rise to large energy shifts between bulk and surface in both the N1s XPS and XAS. The origin of the surface core-level shift is attributed to the presence of non-hydrogen-bonded nitrogen atoms in the surface layer.

The interaction of lithium, sodium and potassium with an oxidised Ni(110) single crystal surface has been investigated using X-ray photoelectron spectroscopy (XPS). Incorporation of the alkali metal into the oxide layer at room temperature results in the suppression of the intrinsic Ni(2p) satellite structure of stoichiometric NiO, confirming its origin in an inter-site screening process in accordance with a recent theoretical model. In addition, the reaction of the alkali metal with NiO at higher temperatures gives rise to a divalent or trivalent nickelate species. The effect of water vapour on nickelate formation and the reactivity of the nickelate to carbon monoxide is also investigated.

Interleukin (IL)-2, a critical cytokine with indispensable functions in regulating lymphoid homeostasis, induces the activation of several biochemical pathways. Precisely how these pathways are linked and how they relate to the biological action of IL-2 is incompletely understood. We previously identified SHP-2 (Src homology 2 domain containing phosphatase 2) as an important intermediate in IL-2-dependent MAPK activation and showed its association with a 98-kDa phosphoprotein in response to IL-2. Here, we demonstrate that Gab2, a recently identified adapter molecule, is the major SHP-2 and phosphatidylinositol 3'-kinase-associated 98-kDa protein in normal, IL-2-activated lymphocytes. We further demonstrate that phosphorylation of both Gab2 and SHP-2 is largely dependent upon tyrosine 338 of the IL-2 receptor beta chain. Gab2 can be a substrate of all the three major classes of non-receptor tyrosine kinases associated with the IL-2R, but in terms of IL-2 signaling, JAK3 but not Lck or Syk is essential for Gab2 phosphorylation. We also demonstrate that only IL-2 and IL-15, but not other gammac cytokines induce Gab2 phosphorylation; the ability to phosphorylate Gab2 correlates with Shc phosphorylation and ERK1/ERK2 activation. Finally, we also show that Gab2 levels are regulated by T cell activation, and resting T cells express little Gab2. Therefore, up-regulation and activation of Gab2 may be important in linking the IL-2 receptor to activation of MAPK and may be an important means of achieving specificity in cytokine signaling.

Platelet aggregation is intimately involved in the pathophysiology of acute coronary syndromes. Blockade of the platelet glycoprotein IIb/IIIa receptor, the mediator of platelet aggregation induced by all physiologic agonists, prevents arterial thrombosis in animal models far more effectively than aspirin. Eptifibatide (Integrilin ™) is a rapidly reversible competitive inhibitor of glycoprotein IIb/IIIa studied in a broad range of ischaemic coronary conditions, including percutaneous coronary intervention, ST-segment and non-ST-segment acute myocardial infarction and unstable angina. In each case, therapy with eptifibatide has reduced acute ischaemic complications without any increased risk of life-threatening bleeding or adverse events. Based on data from the Integrelin to Minimize Platelet Aggregation and Coronary Thrombosis (IMPACT) II study, a salutary benefit in the range of a 20 - 25% reduction in adverse clinical events can be expected in patients undergoing coronary intervention. Few significant pharmacological effects other than inhibition of platelet aggregation and the effect on bleeding time have been reported. Future research will focus on alternative doses, infusion regimens and combinations with other therapies to improve further cardiovascular outcomes.

Summary The ultrastructural changes in a feline embryo continuous cell line infected with feline calicivirus at a multiplicity of infection of approximately 1 were studied. Virus was found only in the cytoplasm and was observed as single particles, as extensive, non-regular accumulations, as paracrystalline arrays, and as single or multiple linear arrays associated with microfibrils. Mature virus particles were readily distinguished from ribosomes in that they were larger (35 nm diameter) and consisted of a central, electron-dense core 20 nm diameter surrounded by a less electron-dense coat.

Summary Feline embryo (FEmb) cell cultures, in which 90 percent of cells were dividing (cycling), were synchronized, by serum deprivation, to the degree that 88 per cent of the cells divided within a 12 hour period. When such cultures were infected with feline panleukopenia virus (FPV) at a multiplicity of infection of 5.7, a maximum level of cell associated virus was attained 28 hours post-infection (p.i.). There was a tendency for virus to remain cell associated in that cell lysis did not begin until 40 hours p.i.

1. Intracellular recordings were made from pacemaker cells lying in the sino‐atrial node of guinea‐pigs. 2. Low‐frequency vagal stimulation slowed the rate of generation of pacemaker action potentials; high‐frequency stimulation stopped the generation of action potentials. 3. During vagal stimulation the rate of diastolic depolarization was reduced with the action potential otherwise unchanged: when the heart stopped the membrane potential of pacemaker cells settled to a value positive of the maximum diastolic potential. 4. In contrast, added acetylcholine caused membrane hyperpolarization and shortened the duration of action potentials. 5. The effects of both added acetylcholine and vagally released acetylcholine were abolished by hyoscine. 6. It is suggested that neurally released acetylcholine acts to change the balance between inward and outward current flow during diastole by modifying the properties of existing voltage‐dependent channels. In contrast added acetylcholine appears to activate a different set of receptors which increase the potassium conductance of pacemaker cells.

1. The effects of vagal stimulation and applied acetylcholine were compared on the isolated sinus venosus preparation of the toad, Bufo marinus. 2. The effects of applied acetylcholine and of low‐frequency, or short bursts of high‐frequency vagal stimulation were abolished by hyoscine. 3. When intracellular recordings were made from muscle cells of the sinus venosus, it was found that applied acetylcholine caused bradycardia and a cessation of the heart beat which was associated with membrane hyperpolarization and a reduction in the duration of the action potentials. Much of the effect of acetylcholine can be attributed to it causing an increase in potassium conductance, gK. 4. When slowing was produced by low‐frequency vagal stimulation, only a small increase in maximum diastolic potential was detected. During vagal arrest the membrane potential settled to a potential positive of the control maximum diastolic potential. 5. In the presence of barium, much of the bradycardia associated with vagal stimulation persisted. Although the bradycardia produced by added acetylcholine also persisted in the presence of barium, the effects of acetylcholine that could be attributed to an increase in gK were abolished. 6. Addition of caesium ions produced bradycardia with membrane potential changes similar to those seen during vagal stimulation. 7. The results are discussed in relation to the idea that neuronally released acetylcholine reduces inward current flow during diastole. In contrast applied acetylcholine as well as reducing inward current flow during diastole also increases outward current flow by increasing gK.

1. The effects of sympathetic nerve stimulation on the generation of pacemaker action potentials, recorded from the sino‐atrial node of the guinea‐pig, were determined by using intracellular recording techniques. 2. Trains of stimuli applied to the right stellate ganglion led to an increase in heart rate after a delay of a few seconds. During the initial phase of the tachycardia the rate of discharge of pacemaker action potentials increased and the rate of diastolic depolarization increased, but both the peak diastolic potential and the maximum rate of rise of the action potentials were reduced. During the later phase of the tachycardia the peak diastolic potential, the amplitude of the action potentials, the maximum rate of rise and the rate of repolarization of the action potentials were increased. 3. When membrane potential recordings were made from sino‐atrial node cells, in which beating had been abolished by adding the organic calcium antagonist nifedipine, sympathetic nerve stimulation initiated excitatory junction potentials (EJPs) which had time courses similar to those of the tachycardias recorded from beating preparations. 4. Although both the tachycardias produced by either sympathetic nerve stimulation or added noradrenaline were largely abolished by beta‐adrenoceptor antagonists, the membrane potential changes recorded during the responses to sympathetic nerve stimulation or added noradrenaline were different. Bath‐applied noradrenaline caused a tachycardia which was associated with an increase in the amplitudes of pacemaker action potentials, an increase in the peak diastolic potential and a shortening in the duration of pacemaker action potentials. 5. The addition of agents which cause the accumulation of cyclic AMP in the cytoplasm of the cells produced a tachycardia which was associated with a similar sequence of changes in the membrane potentials to those produced by added noradrenaline; again the membrane potential changes produced by these agents differed from those produced by sympathetic nerve stimulation. 6. The results are discussed in relation to the idea that neurally released noradrenaline activates a set of receptors which cause tachycardia by increasing inward current flow during diastole, whereas added noradrenaline activates a set of receptors that are linked to a cyclic AMP‐dependent pathway which modifies the properties of some of the voltage‐dependent channels involved in pacemaking activity.

Plasma fibronectin (Fn) induces phagocytosis of C3b-opsonized sheep erythrocytes (EC3b) by human peripheral blood monocytes. However, Fn does not induce erythrophagocytosis of EC3b by human polymorphonuclear leukocytes (PMN), unless the PMN have been exposed to C5a or N-formyl- methionyl-leucyl-phenylalanine. Because of this difference, it is of great interest to examine Fn binding to cells that possess the capacity to differentiate into either granulocytes or monocytes. Hence, we have examined the consequences of Fn binding to the human myelomonocytic cell line, HL-60, both before and after in vitro differentiation of the HL-60, along a monocytoid or a granulocytoid pathway. Fn receptors were not found on undifferentiated HL-60, but several differentiating agents promoted the HL-60 binding of Fn-coated microspheres (Fn-ms). The peak of Fn-ms binding occurred four to five days after the induction of differentiation with dimethylsulfoxide (DMSO), and two days after induction by PMA. In addition, cells that differentiated along either the monocytoid or the granulocytoid pathway showed a marked increase in the phagocytosis of both IgG-coated erythrocytes (EA) and EC3b when they were exposed to Fn. Comparison of the effects of anti-Fn monoclonals on the binding of Fn-ms to the monocytes, PMN, and HL-60 showed that the same monoclonals block Fn-ms-binding and Fn-induced EC3b phagocytosis by all three cell types. Two monoclonal antibodies, M1/70 and A6F10, directed against membrane antigens on PMN and monocytes, inhibited Fn-ms binding. Both also blocked Fn-induced EC3b ingestion by these cells. However, neither antibody blocked Fn-ms binding or EC3b ingestion by differentiated HL-60. We conclude that differentiated HL-60 cells express functionally active Fn receptors, similar to monocytes and activated PMN, which, nonetheless, differ from normal cells in their association with the antigens recognized by M1/70 and A6F10.

Changes in small blood vessels of corpora lutea (CL) undergoing cyclical regression were studied by light and electron microscopy, and the progesterone content of some CL was assayed. Vascular changes were first identified at Day 14 of the estrous cycle, were consistently present by Day 16, and were observed in all CL in which progesterone content was <10 µg/g luteal tissue. Vascular changes involved both the luminal contents and walls of capillaries and small venules. Many capillaries contained degenerating cellular fragments, incorporating nuclear and cytoplasmic remnants, together with blood cells. The walls of many vessels containing cellular fragments appeared normal. In others, abnormalities observed included folding of the basal lamina, increase in the size and number of gaps in the endothelium, increased endothelial cell projection into the lumen, the inclusion of hetero- and/or autophagic vacuoles in the cytoplasm of many endothelial cells and pericytes, and endothelial cell degeneration leading to ultimate disintegration of affected vessels. By Day 1 of the following cycle the number of capillaries was much reduced. It was concluded that, at a relatively early stage of luteolysis, many luteal capillaries show changes involving obstruction of their lumina by large amounts of cellular debris, at least a part of which is of endothelial origin. The relationship of these changes to other phenomena associated with luteolysis is discussed.

Reduced trichostrongylid infection on herbage and in calves was obtained when first-season calves, grazing a common area of pasture, received low-dosage phenothiazine (ptz) in two successive years. The average daily dose of ptzwas 7·0 or 10–3 mg kg−1in the first year and, in the second, between 5·0 and 7·0 mg kg−1. The effect on herbage infection was attributed mainly to ovicidal action. Treatment increased weight gain by 22 and 50 to 60 per cent in the respective seasons. The results suggested a cumulative effect produced by treating calves of successive years. Two calves developed ptz-induced photosensitivity (corneal opacity) in the first season, and two calves in the second season but in the latter, severe bronchopneumonia was believed to be a predisposing factor. To avoid photosensitivity and still maintain adequate drug activity, the daily intake of ptzshould probably be restricted to around 6 mg kg−1.

Positioning control systems for robot arms are presented within a general framework in view of unification and classification. Treating coupling torques from other links as an external disturbance reduces the design of the control system to that of SISO servomechanisms driving each of the robot axes individually. A short survey of many control strategies proposed in the literature presents them as different methods aiming at attenuation of this disturbance. The use of disturbance observers is shown to provide a nice and simple way for that purpose. This could be applied to the improvement of actual industrial robots at the cost of slight software modifications.

Interleukin 12 (IL-12) is an important immunoregulatory cytokine whose receptor is a member of the hematopoietin receptor superfamily. We have recently demonstrated that stimulation of human T and natural killer cells with IL-12 induces tyrosine phosphorylation of the Janus family tyrosine kinase JAK2 and Tyk2, implicating these kinases in the immediate biochemical response to IL-12. Recently, transcription factors known as STATs (signal transducers and activators of transcription) have been shown to be tyrosine phosphorylated and activated in response to a number of cytokines that bind hematopoietin receptors and activate JAK kinases. In this report we demonstrate that IL-12 induces tyrosine phosphorylation of a recently identified STAT family member, STAT4, and show that STAT4 expression is regulated by T-cell activation. Furthermore, we show that IL-12 stimulates formation of a DNA-binding complex that recognizes a DNA sequence previously shown to bind STAT proteins and that this complex contains STAT4. These data, and the recent demonstration of JAK phosphorylation by IL-12, identify a rapid signal-transduction pathway likely to mediate IL-12-induced gene expression.

The Janus family of kinases (JAKs) has been shown to be involved in the signal transduction of a number of cytokine receptors. Recently, we have cloned a novel JAK family member, JAK3, that is expressed in natural killer and activated T cells and is coupled functionally and physically to the interleukin 2 (IL-2) receptor in these cells. Here we report that JAK3 was expressed at low but detectable levels in human monocytes. In contrast, JAK3 expression was strongly induced during activation by interferon gamma (IFN-gamma) or lipopolysaccharide. Moreover, JAK3 became tyrosine phosphorylated in response to IL-2, IL-4, and IL-7 but not response to IFN-gamma or granulocyte/macrophage colony-stimulating factor. Together, these findings suggest that JAK3 is functionally important in activated monocytes and cells of the myeloid lineage and is involved in signaling responses of cytokines that use the common gamma-chain of the IL-2 receptor.

A method has been developed for preparation of purified desmin from mature mammalian (porcine) skeletal muscle. A crude desmin-containing fraction was prepared by modification of procedures used for isolation of smooth-muscle intermediate-filament protein [Small & Sobieszek (1977) J. Cell Sci. 23, 243-268]. The desmin was extracted in 1 M-acetic acid/20 mM-NaCl at 4 degrees C for 15h from the residue remaining after actomyosin extraction from washed myofibrils. Successive chromatography on hydroxyapatite and DEAE-Sepharose CL-6B in 6M-urea yielded desmin that was routinely more than 97% 55 000-dalton protein and that had no detectable actin contamination. Removal of urea by dialysis against 10mM-Tris/acetate (pH 8.5)/1 mM dithioerythritol and subsequent clarification at 134 000 g (rav. 5.9 cm) for 1 h results in a clear desmin solution. Dialysis of purified desmin against 100 mM-NaCl/1 mM-MgCl2/10 mM-imidazole/HCl, pH 7.0, at 2 degrees C resulted in the formation of synthetic desmin filaments have an average diameter of 9-11.5 nm. The present studies demonstrate that the relatively small amount of desmin in mature skeletal muscle can be isolated in sufficient quantity and purity to permit detailed studies of its properties and function. Although 10nm filaments have not been unequivocally demonstrated in mature muscle in vivo, that the purified skeletal-muscle desmin will form 10 nm filaments in vitro lends support to their possible existence and cytoskeletal function in mature skeletal-muscle cells.

Prostaglandin F2α(PGF2α) or saline was infused into sheep on Day 7 or 8 after estrus. Infusions were made into the uterine vein, ipsilateral to the ovary bearing a corpus luteum (CL), or into a jugular vein at dose rates of 1000–20 μg/h for 3–9 h. Plasma progesterone levels were suppressed to low levels in those ewes which received PGF2αinto the uterine vein but not in ewes which received saline into the uterine vein. In three ewes which received PGF2αby the systemic route (200 μg/h or 500 μg/h for 3 h), some reduction in plasma progesterone concentration occurred in the one animal infused at the higher dose.These findings give support to the hypothesis that a countercurrent mechanism, by means of which a uterine luteolysin could be transferred from the uterine vein into the ovarian artery, may exist in the sheep. Histological studies in one animal suggest that PGF2αmay cause luteolysis as a result of interference with the arteriolar blood supply of the CL.

Contractility in vitrowas studied in strips of tissue from the walls of 35 ovarian follicles from sheep. Thirty-two of these follicles showed contractions either spontaneously or after the administration of drugs.Spontaneous rhythmic contractions were observed in 14 follicles after the application of small amounts of tension. Contractions, involving marked increases in tone, sometimes associated with onset or increase of rhythmic contractility, were elicited by epinephrine, norepinephrine, acetyl choline, carbachol, and prostaglandin F2α. Relaxation was induced by isoproterenol, histamine, 5-hydroxytryptamine, and prostaglandin E2. Responses to oxytocin were variable. The effects of α-adrenergic drugs were blocked by tolazoline and phentolamine, those of isoproterenol by propranolol, and those of cholinergic drugs by atropine.Contractile responses were demonstrated at all stages of the estrous cycle as recognized by histological examination of corpora lutea, and appeared stronger at late than at early or midstages of the cycle. The strongest contractions recorded were in large luteinized follicles.These results demonstrate that contractility is a property of the walls of ovarian follicles in sheep, and indicate a range of responses to pharmacological agents.

Four laboratory sessions bearing on direct digital control are presented. The basic considerations for the laboratory arrangement are exposed and the equipment is briefly reviewed. The main topics of these sessions deal with the quantization effects, the sampling phenomena, the performances of a DDC loop for controling a first-order plant and for controling a second-order plant. The pedagogical objectives are then discussed. After the conclusions are summarized.

1. The role of nitric oxide (NO) in the regulation of coronary flow and mechanical function was studied in isolated working rat hearts. 2. The inhibition of basal release of NO by L‐Ng‐monomethylarginine (L‐NMMA; 500 microM), a specific inhibitor of its synthesis, induced a reduction of coronary flow to 39.1% (+/‐ 3.4) of its basal level. 3. Associated with this was a drop of cardiac output to 58.10% (+/‐ 5.42) of control values. 4. This mechanical dysfunction, which was more pronounced in hypertrophied hearts, appears to be related to ischaemia, as it was prevented by simultaneously administered glyceryl trinitrate. Furthermore, L‐NMMA did not alter the contractile activity of isolated cardiac myocytes, thereby excluding a direct toxic effect. 5. These findings provide evidence that NO plays a crucial role in the maintenance of basal coronary flow and appears to be essential for sustaining mechanical activity.

The function of the metrial gland of the rat, and particularly of its characteristic population of granulated cells, remains unknown. However, several lines of evidence suggest that the granulated cells may derive from lymphocytes, and play a role in the immunology of pregnancy. In this study, antigen expression by granulated and other cell populations from the metrial glands of rats at Days 13 and 14 of pregnancy was studied by an indirect immunoperoxidase method. Acetone-fixed frozen sections, and cytocentrifuge preparations of collagenase-dispersed metrial gland tissue in which numbers of granulated cells had been increased by density-gradient centrifugation, were used. The primary antibodies used recognised, inter alia, B lymphocytes (MRC OX-3, MRC OX-6, MRC OX-12), T lymphocytes (MRC OX-8, W3/25, MRC OX-19), neutrophils (MRC OX-42) and cells of the monocyte/macrophage series (MRC OX-3, MRC OX-6, MRC OX-42, MRC OX43). The majority of the granulated cells, including smaller, “immature” forms, were unlabelled by any of these antibodies. Some lymphocytes, and varying numbers of larger, non-granulated cells, were labelled by OX-6, OX-12, W3/ 25, OX-42 and OX-43. In addition to lymphocytes, labelled cells included neutrophils (OX-42), endothelial cells (OX-43), and probably some macrophages (OX-6, OX-43). OX-12, which recognises the kappa chain of rat IgG, labelled some large cells which may have been stromal cells. These findings do not support the concept that the granulated cells are derived from lymphocytes.

Summary.The cellular composition of CL from 6 cows on ∼Day 12 of the oestrous cycle, after synchronization with cloprostenol, was studied by ultrastructural morphometry. Point-count measurements of volume density (mean ± s.d.) showed that large luteal cells occupied 40·2 ± 7·0% of the luteal tissue, and small luteal cells 27·7 ± 6·3%. Of the total of 393·4 ± 52·0 × 103cells per mm3of luteal tissue, large luteal cells made up only 3·5% and small luteal cells 26·7%, a ratio of 1:7·6. Endothelial cells/pericytes, at 52·3%, were the most numerous cell type. The mean volume per large luteal cell was 29·6 ± 6·3 × 103μm3, while that of small luteal cells was 2·7 ± 0·4 × 103μm3. In spherical form, these volumes would represent mean diameters of 38·4 μm and 17·2 μm respectively, and are consistent with published measurements on dispersed luteal cells. However, the values for cell numbers are much higher than published values based on luteal tissue dispersion, suggesting that dispersion may result in substantial and possibly selective losses of luteal cells.Keywords:corpus luteum; oestrous cycle; cow; morphometry; luteal cells

Normal oestrous cycles occurred in five ewes in which the left uterine horn was congenitally absent. In all of these ewes, the blood vessels supplying the left ovary were essentially normal, and large uterine veins drained into the left utero-ovarian vein. Normal cyclical activity in these circumstances is consistent with a mechanism of luteolysis involving local countercurrent transfer of prostaglandin F2αin the uterine and ovarian vessels.

Summary.Corpora lutea from cyclic ewes were dissociated by collagenase digestion and trypsin/EGTA treatment. Enriched fractions of endothelial cells, small luteal cells and large luteal cells were prepared on a stepped gradient of Ficoll 400. Progesterone was measured by radioimmunoassay and the results corrected so that progesterone production by each cell type could be determined. Endothelial cells did not produce significant amounts of progesterone, with or without LH stimulation, and endothelial cell contamination of small and large luteal cell fractions did not influence progesterone production by these fractions. Mean ± s.e.m. basal progesterone production (n= 10) by large luteal cells was greater (P< 0·001) on a per cell basis than that by small luteal cells (1·16 ± 0·16 compared with 0·25 ± 0·06 pg/h/cell). However LH, which stimulated a maximal 3–4-fold increase in progesterone production by small luteal cells (LH ED50= 0·14 ng/ml), had no significant effect on production by large luteal cells, when contamination by small luteal cells was taken into account. The response of small luteal cells was specific to LH, other hormones having had no significant effect.Basal progesterone production by small luteal cells (0·12 ± 0·03 fg/h/μm3) calculated per unit volume of cell was not significantly different from that of large luteal cells (0·17 ± 0·02 fg/h/μm3). After LH stimulation, small luteal cells produced more progesterone than did large luteal cells (0·40 ± 0·09 compared with 0·18 ± 0·03 fg/h/μm3) (P< 0·05). When the amounts of progesterone produced per cell were multiplied by the absolute numbers of large luteal (1 × 107) and small luteal (5 x 107) cells in the intact corpus luteum, basal progesterone production by large luteal cells (11·6 ± 1·6 μg/h) was similar to that by small luteal cells (12·3 ± 3·0 μg/h). However, under LH stimulation, progesterone production by the small luteal cell type (39·9 ± 9·5 μg/h) was ∼ 3 times greater than that by the large luteal cell type (12·3 ± 1·6 μg/h) (P< 0·05).We therefore conclude that small luteal cells may be the principal source of luteal progesterone production in the sheep.

Summary.Ovarian and luteal blood flow rates were studied using radioactive microspheres in guinea-pigs between Day 6 of the oestrous cycle and Day 1 of the following cycle. Peripheral plasma progesterone levels were measured by radioimmunoassay on the same days of the oestrous cycle.Ovarian blood flow was greatest between Days 9 and 12 and had fallen by Day 16 both in absolute (ml·min−1) and relative (ml·min−1·g−1) terms. Luteal weight and blood flow were also greatest between Days 9 and 12 and had fallen sharply by Day 16. The highest mean (±s.d.) luteal flows measured were 0·10 ± 0·04 ml · min−1per corpus luteum, and 24·26 ± 9·3 ml · min−1· g−1luteal tissue on Day 10 of the cycle. Mean peripheral plasma progesterone levels reached a maximum of 3·66 ± 1·1 ng/ml at Day 12 of the cycle and fell thereafter, reaching 0·74 ± 0·5 ng/ml by Day 1 of the following cycle. Plasma progesterone levels declined significantly between Days 12 and 14 of the cycle, whereas no significant drop in luteal blood flow was demonstrable until after Day 14. These data do not support the idea that declining luteal blood flow is an initiating mechanism in luteal regression in the guinea-pig.

The interleukin (IL)-2 receptor system has previously been shown to signal through the association and tyrosine phosphorylation of Shc. This study demonstrates that the IL-2 receptor beta (IL-2R beta) chain is the critical receptor component required to mediate this effect. The use of IL-2R beta chain deletion mutants transfected into a Ba/F3 murine cell model describes a requirement for the IL-2R beta "acid-rich" domain between amino acids 315 and 384 for Shc tyrosine phosphorylation and receptor association. COS cell co-transfection studies of IL-2R beta chain constructs containing point mutations of tyrosine to phenylalanine along with the tyrosine kinase Jak-1 and a hemagglutinin-tagged Shc revealed that the motif surrounding phosphorylated tyrosine 338 within the acid-rich domain of the IL-2R beta is a binding site for Shc. Deletion of this domain has previously been shown to abrogate the ability of IL-2 to activate Ras but does not affect IL-2-dependent mitogenesis in the presence of serum. Proliferation assays of Ba/F3 cells containing IL-2R beta chain deletion mutants in serum-free medium with or without insulin shows that deletion of the acid-rich domain does not affect IL-2-driven mitogenesis regardless of the culture conditions. This study thus defines the critical domain within the IL-2R beta chain required to mediate Shc binding and Shc tyrosine phosphorylation and further shows that Shc binding and phosphorylation are not required for IL-2-dependent mitogenesis. Neither serum nor insulin is required to supplement the loss of induction of the Shc adapter or Ras pathways, which therefore suggests a novel mechanism for mitogenic signal transduction mediated by this hematopoietin receptor.

The signaling molecules insulin receptor substrate (IRS)-1 and the newly described IRS-2 (4PS) molecule are major insulin and interleukin 4 (IL-4)-dependent phosphoproteins. We report here that IL-2, IL-7, and IL-15, as well as IL-4, rapidly stimulate the tyrosine phosphorylation of IRS-1 and IRS-2 in human peripheral blood T cells, NK cells, and in lymphoid cell lines. In addition, we show that the Janus kinases, JAK1 and JAK3, associate with IRS-1 and IRS-2 in T cells. Coexpression studies demonstrate that these kinases can tyrosine-phosphorylate IRS-2, suggesting a possible mechanism by which cytokine receptors may induce the tyrosine phosphorylation of IRS-1 and IRS-2. We further demonstrate that the p85 subunit of phosphoinositol 3-kinase associates with IRS-1 in response to IL-2 and IL-4 in T cells. Therefore, these data indicate that IRS-1 and IRS-2 may have important roles in T lymphocyte activation not only in response to IL-4, but also in response to IL-2, IL-7, and IL-15.

Protein-tyrosine kinase and protein-tyrosine phosphatase (PTPase) activities are essential for T-cell antigen receptor-mediated signaling. To assess the functional consequences of alteration of the levels of tyrosine phosphorylation in normal human T cells, the effects of vanadate and hydrogen peroxide were studied. In combination, these agents induced tyrosine phosphorylation of cellular substrates, elevated cytosolic free calcium, and induced interleukin 2 receptor (IL-2R) alpha chain expression but not IL-2 secretion. However, anti-CD28 antibody in combination with vanadate and hydrogen peroxide induced IL-2 secretion, consistent with the requirement for a costimulatory signal in the induction of this gene. The effects of vanadate and hydrogen peroxide were enhanced in the absence of the T-cell PTPase, CD45. Thus, acute pharmacologic manipulation of the level of tyrosine phosphorylation in normal T cells correlates with partial, but not full, activation of these cells; in concert with a costimulatory signal provided by perturbation of the CD28 molecule, the complete program of activation is initiated. These agents should prove useful in dissecting signaling pathways involved in the regulation of genes critical to the immune response.

The fate of the theca interna after ovulation was studied in ewes, using light and electron microscopic histology and histochemistry. At the time of ovulation the theca interna was incorporated, apparently completely, into the margin of the developing corpus luteum and into the centres of many infoldings of the follicular wall. There was no evidence of degeneration of the more highly differentiated theca interna cells at or following the time of ovulation. Within 24 h of ovulation, cells derived from the theca interna began migrating from their original sites into the deeper, granulosa-derived areas of the luteal tissue. At later stages cells derived from the theca interna remained concentrated in septa derived from the follicular infoldings, but were also widely distributed throughout the luteal tissue. Structural evidence supported the view that the small luteal cells and fibroblasts of the corpus luteum were derived from the theca interna, and the large luteal cells from the membrana granulosa.

Mutations affecting the expression of the Janus family kinase JAK3 were recently shown to be responsible for autosomal recessive severe combined immunodeficiency (SCID). JAK3-deficient patients present with a clinical phenotype virtually indistinguishable from boys affected by X-linked SCID, a disease caused by genetic defects of the common gamma chain (gamma c) that is a shared component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15. The specific interaction of JAK3 and gamma c represents the biochemical basis for the similarities between these two immunodeficiencies. Both forms of SCID are characterized by recurrent, severe infections leading to death in infancy unless successfully treated by allogeneic bone marrow transplantation. Because of the potentially lethal complications associated with allogeneic bone marrow transplantation and the frequent lack of suitable marrow donors, the development of alternative forms of therapy is highly desirable. To this end, we investigated a retroviral-mediated gene correction approach for JAK3-deficiency. A vector carrying a copy of JAK3 cDNA was constructed and used to transduce B cell lines derived from patients with JAK3-deficient SCID. We demonstrate restoration of JAK3 expression and phosphorylation upon IL-2 and IL-4 stimulation. Furthermore, patients' cells transduced with JAK3 acquired the ability to proliferate normally in response to IL-2. These data indicate that the biological defects of JAK3-deficient cells can be efficiently corrected in vitro by retroviral-mediated gene transfer, thus providing the basis for future investigation of gene therapy as treatment for JAK3-deficient SCID.