Protective effects of intermedin/adrenomedullin-2 in a cellular model of human pulmonary arterial hypertension

Proliferation of pulmonary fibroblasts (PF) and distal migration of smooth muscle cells (PSM) are hallmarks of pulmonary arterial hypertension (PAH). Intermedin/adrenomedullin-2 (IMD/AM2) belongs to the Calcitonin Gene-Related Peptide (CGRP)/Adrenomedullin (AM) superfamily. These peptides act via Calcitonin-Like Receptors (CLR) combined with one of three Receptor activity-modifying proteins (RAMPs). IMD/AM2 is a potent pulmonary vasodilator in animal studies. The aim was to describe expression of IMD/AM2, AM and receptor components in human pulmonary vascular cells and to elucidate effects of IMD/AM2 on human PSM migration and PF proliferation. Gene expression was detected by immunofluorescence, immunoblotting and qRT-PCR. Normotension and hypertension were simulated by applying pulsatile mechanical stretch (Flexcell® apparatus). Viable cell numbers were determined by dye exclusion. PSM chemotaxis was measured via Dunn chamber. IMD/AM2 protein was co-expressed with AM and their receptor components in pulmonary artery and microvascular endothelial (PAEC, PMVEC) and non-endothelial cells (PF, PSM), and localised to vesicles. IMD/AM2 was secreted under basal conditions, most abundantly from PF and PMVEC. Secretion from PF and PSM was enhanced by stretch. IMD/AM2 mRNA expression increased in response to hypertensive stretch of PSM. IMD/AM2 inhibited PDGF (10^-7 M)-mediated PSM migration maximally at 3 × 10^-10 M and PF proliferation maximally at 3 × 10^-9 M. Angiotensin II (5 × 10^-8 M), normotensive and hypertensive stretch augmented PF proliferation. IMD/AM2 (10^-9 M) abolished the proliferative effects of Angiotensin II and normotensive stretch and attenuated the proliferative effect of hypertensive stretch alone and combined with angiotensin II. These findings indicate an important counter-regulatory role for IMD/AM2 in PAH.

Extensive perinephric abscess complicated by herpes simplex virus 1 reactivation

A 43-year-old man, admitted with a swollen right thigh, was diagnosed with a deep vein thrombosis. On day 6 he became septic. A CT scan demonstrated a right-sided hydronephrosis and a large retroperitoneal collection. Blood cultures and perinephric pus grew Escherichia coli resistant to amoxicillin only. On day 12 a vesicular rash appeared on the neck and herpes simplex virus 1 (HSV-1) grew on culture. On day 15 an upper leg collection was seen on CT scan. Thigh tissue specimens grew extended-spectrum beta-lactamase (ESBL) producing E coli and HSV-1 was also detected by polymerase chain reaction in the tissue. On day 18 the patient died. This case illustrates an unusual presentation and complication of a perinephric abscess. In critically ill patients herpes simplex reactivation and emergence of multiresistant organisms may occur resulting in treatment failure.

Reduction of catheter-related colonisation by the use of a silver zeolite-impregnated central vascular catheter in adult critical care

Central vascular catheters (CVC) are used extensively in critical care for monitoring and therapy. They can become colonised with viable micro-organisms within 24 h of insertion, which can rapidly form biofilm. This colonisation is a precursor of catheter-related bloodstream infections (CR-BSI), which are associated with substantial morbidity, mortality, prolonged hospital stay and increased cost. Antimicrobials have been incorporated into the bulk material of CVC or applied to their surfaces as a coating in an attempt to reduce the incidence of CVC colonisation and infection. This study examines the effect of a silver zeolite-impregnated catheter on catheter-related colonisation and infection in adult critical care patients. The study was conducted in adult Intensive Care Units (ICU) at three acute hospitals over 14 months and involved 246 CVC insertions (122 silver-impregnated and 124 non-impregnated). CVC tip colonisation was detected by the Maki Roll culture and CR-BSI by differential time-to-positivity of blood cultures. Overall colonisation rate was significantly lower in the silver zeolite-impregnated CVC tips (58%) as compared with the control CVC tips (73%) (p<0.025). In addition, there was a lower rate (34%) of tip colonisation by coagulase negative staphylococci in the silver zeolite-impregnated CVC tips as compared with the control CVC tips (47%) (p<0.05). Four episodes of CR-BSI were detected in each arm by differential time-to-positivity in a subset of patients. This study indicates that the silver zeolite-impregnated catheter is superior to non-impregnated catheter in reducing the rate of CVC colonisation but it showed no difference in the rates of CR-BSI in the two arms. Larger prospective randomised control studies are required to evaluate its role in the prevention of CR-BSI.

Collagen type-I degradation is related to arterial stiffness in hypertensive and normotensive subjects

Although arterial stiffness is an independent cardiovascular risk factor associated with both aging and hypertension, relatively little is known regarding the structural changes in the vessel wall that occur with vessel stiffening. We determined if collagen type-I metabolism is related to arterial stiffening in both hypertensive and normotensive subjects. Arterial stiffness was assessed by aortic pulse wave velocity (PWV) and augmentation index (AIx) in 46 subjects (48.7 +/- 2 years, 32 hypertensives) and related to circulating markers of collagen type-I turnover. Collagen synthesis was assessed by the measurement of carboxy-terminal peptide of procollagen type-I (PIP) and collagen degradation by the measurement of carboxy-terminal telopeptide of collagen type-I (ICTP), by quantitative immunoassay. Matrix metalloproteinase-1 (MMP-1) and the tissue inhibitor of metalloproteinase-1 (TIMP-1) were also quantified by immunoassay. The ratio of collagen type-I synthesis to degradation was negatively correlated with both PWV (P<0.05) and AIx (P<0.05), whereas plasma MMP-1 levels displayed a positive correlation with both PWV (P<0.01) and AIx (P<0.01), after adjustment for age and mean arterial pressure. The relationship between collagen type-I turnover and arterial stiffness was similar in both the normotensive and hypertensive subjects. Although circulating markers of collagen synthesis were increased in the hypertensive subjects, this was not related to arterial stiffness. Collagen type-I degradation is increased in relation to collagen type-I synthesis in subjects with stiffer arteries. Matrix metalloproteinase-1, the enzyme responsible for collagen type-I degradation, is positively related to both large elastic and muscular artery stiffness in normotensive and hypertensive subjects.

Aging is associated with increased matrix metalloproteinase-2 activity in the human aorta

BACKGROUND

Aging is a major risk factor for the development of arterial stiffness and vascular disease, and it is related to the upregulation of matrix metalloproteinase-2 (MMP-2) in the aorta of rats and nonhuman primates. This study aimed to determine whether MMP activity in the human vasculature changes with aging. We also assessed regional differences in MMP activity at two locations in the arterial tree, the aorta and the internal mammary artery (IMA).

METHODS

Both MMP-2 and MMP-9 activity in the human aorta and IMA were determined by gelatin zymography and were localized within the tissue using in situ zymography. Tissue inhibitor of metalloproteinase-2 (TIMP-2) levels was determined by Western blot.

RESULTS

Active MMP-2 (but not pro-MMP-2, pro-MMP-9, or active MMP-9) was positively correlated with age in the human aorta (r = 0.65; P < .001) but not in the IMA. Active MMP-2 and TIMP-2 (but not pro-MMP-2 or pro- or active MMP-9) levels are higher in the aorta than in the IMA (P < .001; P < .05). In the aorta, MMP activity is highest in the intima and is also detectable in the media and adventitia. To a lesser extent, MMP activity is present in all layers of the IMA.

CONCLUSIONS

This study demonstrates that age-related MMP-2 upregulation occurs in the human aorta but not in the IMA.

Evaluation of the role of a specialist tracheostomy service. From critical care to outreach and beyond

The impact that a new specialist tracheostomy service, designed specifically for the care of patients with tracheostomies, was assessed in terms of type of tracheostomy tube used, time to first tube change, time to decannulation, and incidence of tracheostomy related complications in a teaching hospital with no on-site ear, nose, and throat facility. A total of 170 patients were studied. After service implementation, fewer patients (17.6%, n = 21) were discharged from the intensive treatment unit to the wards with tracheostomy tubes compared with the first group (39%, n = 20) (p = 0.006), and the number of tracheostomy related complications on the wards were significantly reduced (p = 0.031).

Evaluation of level 1 care facilities for vascular patients

BACKGROUND

A surgical acute care unit (SACU) was established within our hospital to specifically provide level 1 care to surgical patients. We assess the impact that this has had on outcome in vascular patients.

METHODS

All patients undergoing carotid endarterectomy (CEA) and elective abdominal aortic aneurysm repair (AAA) during the first year of SACU were included in the present study. A control group was compiled from patients undergoing the same two procedures in the year preceding the opening of the SACU. Data were collected on admission time, time spent in critical care, outcome and operative cancellations.

RESULTS

During the first year of the SACU there were 28 CEA and 42 AAA repairs performed. In the control group there were 18 CEA and 34 AAA repairs performed. There were no significant differences in death rate or length of hospital stay between the two groups for either AAA repair or CEA. CEA patients in the study group had a significantly reduced level 2 stay (P < 0.001 Mann-Whitney U-test), with 71% of patients being admitted directly to the level 1 facility from theatre. There were less CEA cancelled because of critical care bed shortages among the cases (n = 0) compared to the control group (n = 2), although this did not reach statistical significance (P = 0.15 Fisher's exact test).

CONCLUSIONS

Designated level 1 care has reduced the need for the postoperative admission of CEA patients to level 2 care facilities. It has had no discernible impact on admission time or mortality, but might reduce the number of cancelled operations caused by a lack of level 2 beds.

Positive effect of bumetanide on contractile activity of ventricular cardiomyocytes

Although the beneficial effects of loop-diuretics in relieving congestive heart failure and essential hypertension are well established, there has been limited investigation into the direct cardiac effect of these drugs. The aim of the present study was to investigate mechanical and electrophysiological effects of three loop-diuretics, namely, frusemide, bumetanide and torasemide, in ventricular cardiomyocytes isolated from rabbit myocardium. Contractile performance was assessed using a video edge detection method and effects on L-type Ca(2+) currents were determined using a 'perforated' patch-clamp technique. Unlike frusemide and torasemide, bumetanide produced concentration-dependent (3x10(-8) to 10(-5) M) increases in cell shortening and velocity of cell shortening. Neither frusemide, bumetanide nor torasemide exerted any action on peak Ca(2+) current amplitudes. In summary, the present investigation provides evidence for a direct contractile effect of the loop diuretic, bumetanide, in contrast to absence of effects by frusemide and torasemide, in ventricular cardiomyocytes isolated from rabbit myocardium.

The immediate impact of opening an adult high dependency unit on intensive care unit occupancy

We assessed the hourly occupancy of our intensive care and high dependency units over an 8-week period commencing on the day our high dependency unit opened. Using criteria established by the working group on 'Guidelines on Admission to and Discharge from Intensive Care and High Dependency Units' published by the National Health Service Executive, we defined each patient daily as intensive care or high dependency status. Compared with hourly occupancy figures obtained before the high dependency unit opened, occupancy of the intensive care unit by high dependency patients has been shown to decrease significantly from 21.6% to 11.2%. Use of intensive care beds became more appropriate, their occupancy increasing significantly from 63.7% to 73.4%. A significant decrease in readmissions occurred, supporting the hypothesis that having high dependency beds reduces the number of patients discharged prematurely to the wards.

Occupancy of a teaching hospital adult intensive care unit by high dependency patients

We assessed the hourly occupancy of our intensive care unit by high dependency patients over an 8-week period using the criteria established by the Working Group on Guidelines on Admission to and Discharge from Intensive Care and High Dependency Units published by the National Health Service Executive. High dependency patients accounted for 1914 bed hours (21.6%) out of a potential available total of 8880 hours. Measurement of Therapeutic Intervention Scoring System points and Acute Physiology and Chronic Health Evaluation II scores confirmed that categorising patients according to the new guidelines produced significantly different populations of patients. Mean (standard deviation) Therapeutic Intervention Scoring System points for intensive care status patients were 38.57 (10.40) compared to 21.65 (5.98) points for high dependency status patients (p < 0.001). Median (range) Acute Physiology and Chronic Health Evaluation II score for intensive care status patients was 16 (1-45) compared to 11 (1-27) for high dependency status patients (p < 0.0001). Calculating bed occupancy with different definitions for the whole of our intensive care unit population during the 8 weeks revealed a range of occupancies between 85.3% and 107.3%. We recommend the intensive care unit bed occupancy should be calculated in a standard manner nationally to allow comparison between units. We suggest that hourly occupancy be adopted as the universal method.

Accuracy of pulse oximetry in patients with low systemic vascular resistance

In order to assess the accuracy of pulse oximeters in patients with septic shock, we compared 80 paired readings of oxygen saturations taken from pulse oximeters and oxygen saturations obtained from co-oximetry in patients receiving intensive therapy with indwelling pulmonary artery flotation catheters. Comparison between groups with low or normal systemic vascular resistance indices showed a small (1.4%) but significant (p < 0.001) underreading of the saturation from the pulse oximeter in the presence of a low systemic vascular resistance. With normal or high systemic vascular resistance pulse oximeter readings correlated well with co-oximetry. We hypothesise that the main cause of this underreading is because the pulse oximeter is sensing pulsatile venous flow due to the opening of arteriovenous channels in the skin in septic states.

Hemodynamic effects of intravenous elgodipine in coronary artery disease during rest and exercise, and basic pharmacokinetic parameters

Using an echo-Doppler method (Quantascope), the hemodynamic profile of the calcium channel antagonist elgodipine (64 micrograms/kg, i.v.) was investigated in 22 patients with angina pectoris at rest and during exercise. A placebo control was used. At rest, elgodipine significantly decreased systemic vascular resistance as well as systolic and diastolic blood pressure, while increasing cardiac output and stroke volume. During supine bicycle exercise the constant workload, elgodipine significantly increased cardiac output and stroke volume, and decrease the rate-pressure-product (double product); the exercise systolic blood pressure was decreased without change in the diastolic component. Elgodipine significantly reduced the incidence and severity (self-rated pain score) of exercise-induced anginal systems. Heart rate was not affected by elgodipine, either at rest or during exercise. In particular, no negative inotropy could be inferred from the echo-Doppler data. In the elgodipine plasma concentration profile (HPLC), three phases of elimination with half-life times of less than 1 hour, between 3 and 7 hours, and between 10 and 24 hours may be distinguished, indicating a "shallow" and a "deep" compartment. The hemodynamic data indicate an intermediate pharmacodynamic profile of elgodipine, lying between that of other dihydropyridines and that od compounds such as verapamil or diltiazem.

Dual effects of endothelin-1 on the L-type Ca2+ current in ventricular cardiomyocytes

The effects of endothelin-1 on the L-type Ca2+ current were studied in rabbit ventricular cardiomyocytes, using both the 'perforated' and the conventional 'ruptured' whole-cell patch-clamp techniques. Endothelin-1 exerts a dual effect on ventricular cardiomyocytes using experimental conditions which minimize intracellular dialysis; endothelin-1 produced both an increase (10(-9) M) and a decrease (10(-8) M) in the L-type Ca2+ current using the perforated patch-clamp technique. However, using the ruptured patch-clamp technique, endothelin-1 produced a similar decrease in L-type Ca2+ current at 10(-8) M, but no effect was observed at a concentration of 10(-9) M. These effects suggest multiplicity in the receptor-effector coupling mechanism.

The effect of a carbohydrate-rich beverage on mood, appetite, and cognitive function in women with premenstrual syndrome

OBJECTIVE

To test the efficacy of a specially-formulated, carbohydrate-rich beverage (one known to increase the serum ratio of tryptophan to other large neutral amino acids) on the mood, cognitive, and appetitive disturbances of premenstrual syndrome (PMS).

METHODS

Twenty-four women with confirmed PMS were enrolled in a double-blind, crossover study to test the efficacy of the specially-formulated beverage compared with two other isocaloric products on PMS symptoms. The study was conducted over three menstrual cycles preceded by a 1-month placebo run-in. Patients were tested at home or work using an interactive computer-telephone system. Standardized measurements of mood, cognitive performance, and food cravings were made before and 30, 90, and 180 minutes after consumption of active and placebo beverages during the late luteal phase of the menstrual cycle.

RESULTS

The experimental carbohydrate intervention significantly decreased self-reported depression, anger, confusion, and carbohydrate craving 90-180 minutes after intake. Memory word recognition was also improved significantly compared with scores obtained during the placebo run-in month (P < .05). The isocaloric placebo interventions had no significant effect on any of these measures.

CONCLUSION

The results suggest that the psychological and appetitive symptoms of PMS can be relieved after consuming a specially-formulated, carbohydrate-rich beverage known to increase serum tryptophan levels.

An evaluation of the effect of vasodilatation on oxygen saturations measured by pulse oximetry and venous blood gas analysis

Measurements of arterial oxygen saturation were estimated using a pulse oximeter under conditions of reactive hyperaemia in the arms of 10 volunteers. Oxygen saturation measured by pulse oximetry was significantly lower, and venous oxygen saturation measured by co-oximetry was significantly higher, in the hyperaemic arm than in the other arm. Pulse oximeters analyse the pulsatile component of blood flow and exclude nonpulsatile causes of absorption in estimating arterial oxygen saturation. The pulsatile component is assumed to be purely of arterial origin. However, other vessels may pulsate when vasodilatation occurs and pulse oximeter saturation readings taken under these conditions may not give a true reflection of arterial saturation.

The disruption of marijuana intoxication

Ninety-six males Ss were divided into four drug conditions; coltsfoot, placebo, marijuana low dose, and marijuana high dose. Half of the Ss smoked marijuana while listening to music in a relaxing environment, and half smoked marijuana in the same environment but had two 10-min periods of aversive-noise superimposed over the music. A subjective measure of intoxication demonstrated significant drug and environmental group effects with suppression of self-report of intoxication being especially strong for the marijuana low dose noise group. The usual positive correlation between subjective measures and pulse rate measures of marijuana intoxication was interfered with by the noise effect. Although subjective ratings were suppressed, the noise group demonstrated significantly higher pulse rates than the music group. The results are discussed in terms of the effect of extraneous factors on marijuana intoxication, the significance of dosage in this type of research, and the nature of marijuana intoxication.

Some personality differences among the multidisciplinary team

Professional and student psychologists, social workers, physiotherapists and occupational therapists were administered a demographic questionnaire, the Dogmatism Scale and the Personality Research Form. Significant and trend differences on each of these measures were obtained between the four professional groups, the professional and student groups and the professional groups and the norms for the measures. The possible role of these differences in the operation of the multidisciplinary team is discussed.

Nationwide cerebrovascular disease morbidity study

Previous studies have noted that the geographic differences in stroke mortality among areas of the United States were not due to artifacts of certification practices or accuracy of the diagnosis. A study of hospitalized stroke patients was completed in order to determine whether the mortality differences were due to a higher incidence or case fatality following a stroke in areas with high stroke death rates. Eight of the nine areas that participated in the Nationwide Mortality Study were included in this study. A total of 2,619 stroke cases were ascertained including 1,631 (62.3%) who were alive at the time of hospital discharge, 937 (35.8%) dead at discharge, 46 (1.7%) who were discharged alive but died outside of the hospital, and five (0.2%) who were dead at discharge and certified by the medical examiner.

The incidence of stroke was higher in the high stroke death rate areas especially for men. The ratio of the incidence of stroke in men as compared to women was higher in the younger age groups (45–54, 55–64) and in the high-incidence as compared to low-incidence areas.

The case-fatality percentage was lowest in Denver and highest in South Carolina. Presence of coma on admission was the principal determinant of subsequent mortality in all areas.

Finally, there was no consistent difference in the distribution of symptoms of stroke among the areas, and diagnostic procedures were performed more often in urban than rural areas. Approximately 80% of the stroke cases could be substantiated by either an autopsy verifying diagnosis, arteriography, hemorrhagic spinal fluid, hemiplegia or coma on admission. Several hypotheses to explain the differences have been suggested as well as the need for new information.