Biomechanical dysregulation of SGK-1 dependent aortic pathologic markers in hypertension.

Introduction: In hypertension (HTN), biomechanical stress may drive matrix remodeling through dysfunctional VSMC activity. Prior evidence has indicated VSMC tension-induced signaling through the serum and glucocorticoid inducible kinase-1 (SGK-1) can impact cytokine abundance. Here, we hypothesize that SGK-1 impacts production of additional aortic pathologic markers (APMs) representing VSMC dysfunction in HTN. Methods: Aortic VSMC expression of APMs was quantified by QPCR in cyclic biaxial stretch (Stretch) +/- AngiotensinII (AngII). APMs were selected to represent VSMC dedifferentiated transcriptional activity, specifically Interleukin-6 (IL-6), Cathepsin S (CtsS), Cystatin C (CysC), Osteoprotegerin (OPG), and Tenascin C (TNC). To further assess the effect of tension alone, abdominal aortic rings from C57Bl/6 WT mice were held in a myograph at experimentally derived optimal tension (OT) or OT + 30% +/-AngII. Dependence on SGK-1 was assessed by treating with EMD638683 (SGK-1 inhibitor) and APMs were measured by QPCR. Then, WT and smooth muscle cell specific SGK-1 heterozygous knockout (SMC-SGK-1KO+/-) mice had AngII-induced HTN. Systolic blood pressure and mechanical stress parameters were assessed on Day 0 and Day 21. Plasma was analyzed by ELISA to quantify APMs. Statistical analysis was performed by ANOVA. Results: In cultured aortic VSMCs, expression of all APMs was increased in response to biomechanical stimuli (Stretch +/-AngII,). Integrating the matrix contribution to signal transduction in the aortic rings led to IL-6 and CysC demonstrating SGK-1 dependence in response to elevated tension and interactive effect with concurrent AngII stimulation. CtsS and TNC, on the other hand, primarily responded to AngII, and OPG expression was unaffected in aortic ring experimentation. Both mouse strains had >30% increase in blood pressure with AngII infusion, reduced aortic distensibility and increased PPV, indicating increased aortic stiffness. In WT + AngII mice, IL-6, CtsS, CysC, and TNC plasma levels were significantly elevated, but these APMs were unaffected by HTN in the SMC-SGK-1KO+/- +AngII mice, suggesting SGK-1 plays a major role in VSMC biomechanical signaling to promote dysfunctional production of selected APMs. Conclusion: In HTN, changes in the plasma levels of markers associated with aortic matrix homeostasis can reflect remodeling driven by mechanobiologic signaling in dysfunctional VSMCs, potentially through the activity of SGK-1. Further defining these pathways may identify therapeutic targets to reduce cardiovascular morbidity and mortality.

Integrating Ultrasound-Derived Carotid Artery Stiffness in the Assessment of Cardiovascular Risk.

Historically, pulse wave velocity (PWV) has been used to measure vascular stiffness, but is limited in its utility when certain vascular disease states are present, such as aneurysm or iliac stenosis. PWV can therefore only provide reliable assessment of global vascular stiffness in limited vascular pathology. Speckle tracking is a method of post-hoc ultrasound image analysis that can measure vascular stiffness in a more comprehensive manner. Evidence from in vitro as well as in vivo studies has validated these techniques in the assessment of strain, distensibility, modulus, and stiffness index (ß) in the carotid arterial system. Unfortunately, despite the well-established correlation between vascular stiffness and cardiovascular morbidity and mortality, standard vascular laboratory ultrasound protocols do not include stiffness assessment. Herein, we present evidence in favor of integrating speckle tracking into carotid artery duplex protocols to measure vascular stiffness that can be utilized in medical management to modulate cardiovascular risk.

Nipple differentiation in fetal male rats treated with an inhibitor of the enzyme 5 alpha-reductase: definition of a selective role for dihydrotestosterone.

In the rat, androgens are responsible for sexually dimorphic nipple differentiation. Nipples are expressed in the female, while in the male, the nipple anlage regress prenatally. Mammary gland development is present in both sexes. Treatment of pregnant Sprague-Dawley rats from days 12-21 of gestation with the aza-steroid 17 beta-N,N-diisopropylcarbamoyl-4-aza-5 alpha-androstan-3-one, a competitive inhibitor of the enzyme 5 alpha-reductase, resulted in nipple development in male offspring. Additionally, there was feminization of the external genitalia, with urethral displacement to the base of the phallus. The role of androgens in suppression of nipple anlage in the male rat fetus is known. This study, however, suggests for the first time a selective role for 5 alpha-dihydrotestosterone in regression of the nipple anlage in utero. Thus, 5 alpha-dihydrotestosterone may be critical not only for masculinization of the external genitalia, but also for inhibition of nipple development in the male rat fetus.

Evaluation of a direct immunofluorescence test for diagnosing gonorrhoea.

A new direct immunofluorescence reagent (Syva and Genetic Systems Inc) was evaluated for its ability to detect Neisseria gonorrhoeae in specimens from populations with a high prevalence of the infection. Gonorrhoea was diagnosed by culture in 45 of 105 (43%) urethral specimens from men and 17 of 90 (28%) urethral and 25 of 60 (42%) cervical specimens from women. In men the immunofluorescence test had a sensitivity of 84.4% and a specificity of 100%; Gram staining gave values of 94% and 100%, respectively. The sensitivity of the immunofluorescence test could be increased to 89% by testing duplicate smears. In women the immunofluorescence test had a sensitivity of 65% and a specificity of 98% for urethral samples and values of 72% and 94%, respectively for cervical samples. At both sites the sensitivity of the Gram stain was 40% and the specificity 100%. The testing of duplicate immunofluorescence smears increased the sensitivity to 76% for urethral and 88% for cervical samples.

Side-effects of epidural infusions of opioid bupivacaine mixtures.

The incidence of side-effects occurring with epidural diamorphine (0.05 mg.ml-1), fentanyl (2.0 micrograms.ml-1), methadone (0.1 mg.ml-1), morphine (0.05 mg.ml-1) and pethidine (1.0 mg.ml-1) used by infusion in combination with bupivacaine has been compared. One hundred and sixty patients were studied, 32 receiving each opioid. The incidence of nausea and vomiting was significantly greater with morphine than fentanyl (p = 0.0097) and pethidine (p = 0.0021). The incidence of pruritus was significantly greater with morphine and diamorphine than with methadone (p = 0.012) and pethidine (p = 0.027). Morphine was also associated with a significantly greater incidence of urinary retention than pethidine (p = 0.012) and methadone (p = 0.025).

Pharmacokinetics of analgesics, sedatives and anaesthetic agents during cardiopulmonary bypass.

CPB produces changes in the blood-gas partition coefficient dependent on the prime used and temperature. Fortunately, the overall effect for hypothermic CPB and a crystalloid prime is only +2%. A volatile agent started during hypothermic CPB takes longer to equilibrate and agents already in use need to re-equilibrate, potentially changing the depth of anaesthesia, until equilibration is complete. As these agents are metabolized to a small degree and washout is fast, the duration of action is not prolonged after CPB.

Properties of methicillin-resistant staphylococci now endemic in Australia.

Seventy-eight cultures of multiresistant Staphylococcus aureus (MRSA), obtained from Australian hospitals in 1981, were studied to see whether they possessed novel properties responsible for their epidemic spread. In general, these strains resembled MRSA from other countries and were probably derived from them; in particular, they did not survive desiccation better than other staphylococci. The majority of MRSA produced lipases, which might be responsible for their invasiveness, and all produced high amounts of beta-lactamase which hydrolysed each of the isoxazolyl penicillins. This may account for therapeutic failure with cloxacillin of flucloxacillin. Control of this epidemic should rely principally on general measures against the hospital staphylococcus.

Chromosomal resistance of gonococci to antibiotics.

Three hundred and twenty nine strains of non-penicillinase-producing Neisseria gonorrhoeae (non-PPNG) isolated from men and women were tested for their susceptibility to a range of antibiotics, and were also auxotyped and serogrouped. Nearly 6% (18) of 312 strains tested were resistant to 1 mg/l or more penicillin (compared with 4.4% of PPNG strains isolated in 1981). Many (198, 64%) strains showed intermediate resistance to penicillin (0.12-0.5 mg/l). Nearly 5% (15) of 312 strains tested were resistant to 0.5 mg/l or more cefuroxime, and there was a high degree of cross resistance between these two antibiotics. High levels of resistance to erythromycin and tetracycline were also found, and there was also appreciable cross resistance between these antibiotics and the beta lactam drugs. Resistance to spectinomycin was rare, and there was no cross resistance between spectinomycin and other agents tested. Levels of resistance between strains isolated from different anatomical sites did not differ, except that resistance to erythromycin was greater in rectal isolates. Four main auxotypes were detected. Strains requiring arginine, hypoxanthine, and uracil (AHU-) were more prevalent from the cervix. We have shown that there is an association between auxotype, serogroup, and level of sensitivity to penicillin, cefuroxime, and tetracycline.

Penicillinase producing gonococci: a spent force?

Though the incidence of gonorrhoea caused by penicillinase producing Neisseria gonorrhoeae (PPNG) strains at St Mary's Hospital rose rapidly from 1980 to reach 6.2% in 1982, it declined in 1983 (8.6%) and in 1984 (6.5%), a trend that has continued in 1985. The use of penicillinase stable antibiotics or more effective contact tracing are unlikely to be responsible for this recent decline. We have always isolated very few PPNG strains from homosexual men, and the possible effects of the acquired immune deficiency syndrome (AIDS) on sexual behaviour in this group is therefore unlikely to be relevant. We have seen a steady increase in the proportion of PPNG strains carrying the 4.4 megadalton penicillinase plasmid (67% of PPNG strains in 1984). Strains carrying both the 4.4 megadalton plasmid and the 24.5 megadalton conjugal plasmid were very common in 1982, but since then have declined in importance. PPNG strains carrying the 3.2 megadalton plasmid have become less common, and the presence of the 24.5 megadalton plasmid in these strains has not apparently led to their wider dissemination in the community. Whereas the basic pattern of PPNG auxotypes has changed little, since 1982 we have isolated an increasing number of mixed auxotypes with nutritional requirements other than just proline. PPNG strains carrying the 4.4 megadalton plasmid seem to be more resistant to erythromycin, tetracycline, and streptomycin than those carrying the 3.2 megadalton plasmid. Spectinomycin resistance has only occurred in strains carrying the 4.4 megadalton plasmid.

Extravascular lung water and acute respiratory distress syndrome--oxygenation and outcome.

We studied eleven consecutive patients to assess the influence of extravascular lung water on clinical outcome. All patients were mechanically ventilated using a standardized protocol. Inspired oxygen concentration was adjusted to an initial target PaO2 of greater than 8.0 kPa (60.8 mmHg). All patients received inhaled nitric oxide (NO) at a concentration of 20 ppm. Extravascular lung water index (EVLWI) was measured by a dual indicator technique (COLD Z-021 monitoring system, Pulsion, Munich, Germany). Patients were managed with fluids and inotropes according to a standard protocol. Median age was 45 (range 27-60) years, mean APACHE II score on admission 31 (range 17-36), duration of mechanical ventilation 15 (range 6-28) days, mean admission Murray lung injury score 2.5 (range 2-3) and admission EVLWI 20.8 (range 8.7 to 54.7) ml.kg-1. The only variables independently predictive of PaO2/FiO2 ratio were serum albumin (B = 1.7 +/- 1.61) and EVLWI (B = -2.1 +/- 0.47), r2 = 0.33, P < 0.0001. In severe ARDS, (PaO2/FiO2 < 150 mmHg), mean EVLWI was 24.4 (22.4 to 26.4, 95% confidence intervals) ml.kg-1 compared with 15.1 (12.2 to 18.0) ml.kg-1 during moderate ARDS (P < 0.001). Serum albumin likewise differed, 29.4 (27.6 to 31.2) vs 35.1 (31.8 to 38.4) g.l-1, P < 0.005. PAOP was higher during periods of poor oxygenation, 12.7 (11.9 to 13.5) vs 9.3 (7.9 to 10.7) mmHg, P < 0.001. The four survivors had greater initial EVLWI than non-survivors, 31 (24.1 to 37.9) vs 20.7 (16.0 to 25.4) ml.kg-1, P = 0.034 and showed a greater reduction in lung water, 15.2 (9.3 to 21.1) vs 5.4 (2.1 to 8.7) ml.kg-1, P = 0.013.

Functional iron deficiency, infection and systemic inflammatory response syndrome in critical illness.

To investigate the prevalence and clinical relevance of functional iron deficiency in the critically ill, we performed a prospective observational study in a university hospital general intensive care unit. We collected patient demographics, severity of illness data, haematological and biochemical variables in 51 consecutive admissions. We recorded episodes of culture-positive infection. Functional iron deficiency (FID), measured by red cell hypochromasia on flow cytometry, was present in 35% of patients at admission to intensive care. FID patients were of similar age, diagnosis, APACHE score, sequential organ failure assessment (SOFA) score, haemoglobin, serum B12, folate and ferritin to patients without FID. However, patients with FID had a prolonged intensive care stay compared with non-FID patients (P<0.001) and increased time to hospital discharge (P=0.09). Duration of intensive care stay correlated with severity of FID (r=0.33, P<0.02). Systemic inflammatory response syndrome (SIRS) was present for longer in those with FID (P<0.02). Overall mortality did not differ between groups. No difference was seen in the incidence of positive cultures between those with FID (9/18 patients) and those without FID (15/33 patients). FID was independently associated only with abnormal white blood cell count (WBC < 4 or > 11 x 10(9) x l(-1)) at admission to ICU, P=0.007, but not with positive cultures. There is a high prevalence of FID in intensive care, associated with an increased duration of stay and duration of SIRS. We have been unable to demonstrate a link with infection, either as a predisposing factor or as an acute response.