Low mortality rate in adult respiratory distress syndrome using low-volume, pressure-limited ventilation with permissive hypercapnia: a prospective study

OBJECTIVES

To evaluate the outcome in patients with severe adult respiratory distress syndrome (ARDS) managed with limitation of peak inspiratory pressure to 30 to 40 cm H2O, low tidal volumes (4 to 7 mL/kg), spontaneous breathing using synchronized intermittent mandatory ventilation from the start of ventilation, and permissive hypercapnia without the use of bicarbonate to buffer acidosis. Also, to compare hospital mortality rate with that predicted by the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system and the "ventilator score."

SETTING

A ten-bed general intensive care unit in a university hospital.

DESIGN

Prospective, descriptive study.

PATIENTS

Fifty-three patients with severe ARDS having a lung injury score of > or = 2.5.

INTERVENTIONS

Data recording.

RESULTS

The hospital mortality rate was significantly lower than that predicted by the APACHE II scores (26.4% vs. 53.3%, p = .004), even after correcting the latter for the effect of hypercapnic acidosis (26.4% vs. 51.1%, p = .008). The mortality rate increased with increasing number of organ failures, but was only 43% in patients with > or = 4 organ failures, 20.5% with < or = 3 organ failures, and 6.6% with only respiratory failure. The mean maximum PaCO2 was 66.5 torr (range 38 to 158 torr [8.87 kPa, range 5.07 to 21.07]), and the mean arterial pH at the same time was 7.23 (range 6.79 to 7.45). There was no correlation between the maximum PaCO2 or the corresponding pH and the total respiratory rate at the same time. No pneumothoraces developed during mechanical ventilation.

CONCLUSIONS

These results lend further support to the hypothesis that limitation of peak inspiratory pressure and reduction of regional lung overdistention by the use of low tidal volumes with permissive hypercapnia may reduce ventilator-induced lung injury and improve outcome in severe ARDS. This hypothesis is supported by a large body of experimental evidence, which also suggests that ventilator-induced lung injury may result in the release of inflammatory mediators, and thus may have the potential to augment the development of multiple organ dysfunction. However, the hypothesis requires testing in a randomized trial as acute hypercapnia could potentially have some adverse as well as beneficial effects.

Platelet bacterial contamination and the use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe

BACKGROUND

Currently, the maximum outdate for platelets is 5 days, because of the increasing chance of bacterial growth over time. Various methods for rapid detection of bacterial contamination of blood components have been described, with mixed results and no general acceptance. A recently described, molecular biologic approach for the detection of bacterial contamination involves a chemiluminescence-linked universal DNA bacterial probe to a highly conserved bacterial region of ribosomal RNA (rRNA).

STUDY DESIGN AND METHODS

A multicenter trial of a chemiluminescence-linked universal bacterial rRNA probe for the detection of bacterial contamination in platelet concentrates is described. At each of five sites, platelet concentrates (no older than 1 day from date of phlebotomy) were inoculated in triplicate with isolates of four bacterial species (Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus epidermidis, and Staphylococcus aureus) to a final concentration of 10 to 50 colony-forming units (CFUs) per mL and in triplicate to a final concentration of 1000 CFUs per mL. At one site, an additional 6 platelet concentrates were inoculated with sterile saline to serve as controls. Inoculated units were then subjected periodically to quantitative cultures and probe analyses. A total of 126 platelet concentrates were studied over a period of 7 days (120 inoculated with bacteria and 6 with sterile saline).

RESULTS

This assay was, in some cases, able to detect S. aureus bacterial contamination in the range of 100 to 1000 CFUs per mL; the majority of samples (B. cereus, P. aeruginosa, S. aureus, and S. epidermidis) with contamination exceeding 10(4) CFUs per mL; and all samples with contamination of 2.1 x 10(5) CFUs per mL or greater. Increasing the sample size from the recommended 0.4 mL to 1.0 mL resulted in an unacceptable loss of specificity (83.3%).

CONCLUSION

The routine use of this assay would be expected to result in a decreased risk of septic platelet transfusion reactions and could lead to a lengthening of the current 5 day storage period for platelets. Further, the pooling of random-donor platelet concentrates before storage instead of immediately before transfusion may be possible if this rRNA probe is employed to detect bacteria in the pool.

A small angle X-ray scattering study of the binding of cyclosporin-A to calmodulin

Small angle X-ray scattering (SAXS) was applied to the binding of the immunosuppressant drug cyclosporin-A to the protein calmodulin. Guinier analysis of the SAXS profiles yielded a radius of gyration, Rg, of 19.7 +/- 0.3 A for the native protein and 16.9 +/- 0.3 A for the drug/protein complex. Maximum entropy (maxent) methods of data analysis were used to calculate the distance distribution function, p(r). From this analysis, the Rg for the native protein is 20.9 +/- 0.1 A and that for the complex 16.7 +/- 0.1 A. The measured SAXS profiles and the derived p(r) for calmodulin agree with profiles calculated from the crystallographic structure of calmodulin. Major structural changes are induced in calmodulin on binding cyclosporin-A. A model consistent with the observed scattering profiles is an ellipsoid with major axes 55 and 36 A. Molecular modeling of the calmodulin molecule suggests that bond rotation in the flexible alpha-helix linker region produces models consistent with the above observations.

Epstein-Barr virus-coded BHRF1 protein, a viral homologue of Bcl-2, protects human B cells from programmed cell death

Epstein-Barr virus, a human herpesvirus that persists within the B-lymphoid system, can enhance the survival potential of latently infected B cells in vitro through up-regulation of the cellular survival protein Bcl-2. The possibility that an analogous effect is operative in lytically infected cells was suggested by the observation of distant sequence homology between an Epstein-Barr virus-coded early lytic cycle protein, BHRF1, and Bcl-2. Here we show by gene transfer that BHRF1 resembles Bcl-2 both in its subcellular localization and in its capacity to enhance B-cell survival. Thus confocal microscopic analysis of cells acutely cotransfected with BHRF1 and Bcl-2 expression vectors revealed substantial colocalization of the two proteins in the cytoplasm. In subsequent experiments, stable BHRF1 gene transfectants of Burkitt lymphoma cells paralleled Bcl-2 transfectants in their enhanced survival under conditions that induce cell death by apoptosis. Despite their limited sequence conservation, therefore, the two proteins appear to be functionally homologous. We suggest that BHRF1 provides an alternative, Bcl-2-independent, means of enhancing B-cell survival that may operate during the virus lytic cycle.

Heating patterns of the Helios ultrasound hyperthermia system

Thermal dosimetry studies of the Helios ultrasound system were performed in a tissue-equivalent phantom and in porcine tissues in vivo. SAR distributions in the phantom demonstrate the adjustability of the power deposition pattern from the 50 cm diameter annular array of 30 transducers. Examples are given of well-localized SAR patterns (< 3 cm diameter) in the phantom, and of peripherally enhanced (doughnut-shaped) SAR patterns up to 10 cm in diameter at the focal plane. In vivo trials in porcine thigh muscle demonstrate the ability of the Helios system to produce regions of therapeutic heating (42-45 degrees C) as small as 20 cm3 and as large as 200 cm3 at depths of greater than 10 cm at a frequency of 0.5 MHz.

Physiological and psychological responses to a university fitness session

The purpose of this study was to examine the physiological and psychological responses to a university fitness session entitled 'popmobility'. A popmobility session consists of 20 min of aerobic activities, 5 min of local muscular endurance exercises and 5 min of flexibility exercises. Ten regular participants of these sessions, women of mean(s.d.) age 21.2(1.5) years, took part in the study. A maximal oxygen uptake (VO2max) treadmill test was performed by each subject to obtain VO2max and maximum heart rate values. In a laboratory, heart rate and VO2 were measured throughout a popmobility session for each subject. Rate of perceived exertion (RPE) was measured every 5 min throughout the session. The mean intensity of the aerobic part of the session ranged from 67.7-82.6% of the subject's VO2max (mean of 76.4% VO2max). The mean heart rate reserve for the aerobic section was 75.6%. While the relative oxygen consumption remained fairly static during the aerobic section, the RPE score rose. The mean(s.d.) total energy expenditure was 236.6(28.4) kcal (range 203-288). The popmobility session is of adequate intensity to improve the aerobic fitness of its participants. Heart rate, as used as a measure of intensity during a popmobility session, would appear to be a fairly accurate indicator of intensity. However, the use of RPE for exercise prescription in popmobility sessions is inappropriate. Popmobility could also be useful in a weight-reduction programme.

Duration of periventricular densities in preterm infants and neurological outcome at 6 years of age

Parenchymal echogenicities that break down into extensive cystic lesions are generally followed by severe motor deficit. However, the effect of echodensities in the periventricular white matter, so called 'flares', on later development is less well documented. The aim of the present study was to investigate the impact of neonatal flares in preterm infants on neurological status and motor competence at 6 years of age and to see to what extent outcome was related to duration of flares. Forty four children with flares, subdivided into three groups according to the duration of flares, and 62 children with normal scans were assessed on Touwen's neurological examination, the Movement ABC, and the British Ability Scales. No differences in cognitive abilities were found between the groups. The results of the motor assessments showed that performance decreased significantly with increasing duration of flares. In addition, there was a suggestion that this trend was stronger in measures assessing lower limb function than those of upper limb. Teachers were also able to identify differences between the groups of children on the basis of their motor performance in school.

The disabled elderly living in the community: care received from family and formal services

OBJECTIVES

Based on a community sample, to assess the reasons disabled elderly people need care, the type of formal services they receive, the characteristics of their carers and the degree of psychological morbidity in these carers.

DESIGN AND SETTING

A community survey of people aged 70 or more years living in Canberra or Queanbeyan. Survey participants were asked to nominate informants, who were interviewed about the subjects' state of health. The informants provided information on need for care, services received and the role of carers. Informants also reported on their own health, including symptoms of anxiety and depression.

RESULTS

Elderly people needed care because of physical disability more often than behavioural disability. Those with physical disability received more formal services and more help from health professionals than those with behavioural disability. Contact with general practitioners was high for both disabled and non-disabled subjects. Carers of the physically disabled had raised levels of anxiety and symptoms of depression, and poorer self-rated health, but carers of the behaviourally disabled did not. Wives, daughters and husbands made up the biggest categories of carers and around two-thirds of carers were women.

CONCLUSION

Family carers play an important role in maintaining disabled elderly people in the community and this role is often stressful. Formal services have to be aimed as much at the needs of the carers as at the disabled people themselves.

New modalities under development for adhesion prevention: immunomodulatory agents and poloxamer barrier materials

Obviously, no single modality will prove to be universally applicable or completely effective at preventing postoperative adhesion formation. Increasing understanding of the pathophysiology of peritoneal healing provides the intellectual basis for the development of specific interventions at critical points along the adhesion formation cascade. We believe that multimodality therapy, including the use of pharmacologic adjuvants such as immunomodulatory drugs and fibrinolytic/anticoagulant agents in conjunction with a barrier material tailored to the specific operative procedure may provide optimal results. Hopefully, developments in the 1990's will provide reproductive surgeons with the means to help patients derive maximal benefit from their reconstructive procedures.

The Epstein-Barr virus (EBV) nuclear antigen 1 BamHI F promoter is activated on entry of EBV-transformed B cells into the lytic cycle

In Epstein-Barr virus (EBV)-positive Burkitt's lymphoma cell lines exhibiting the latency I form of infection (i.e., EBV nuclear antigen 1 [EBNA1] positive in the absence of other latent proteins), the EBNA1 mRNA has a unique BamHI Q/U/K splice structure and is expressed from a novel promoter, Fp, located near the BamHI FQ boundary. This contrasts with the situation in EBV-transformed lymphoblastoid cell lines (LCLs) exhibiting the latency III form of infection (i.e., positive for all latent proteins), in which transcription from the upstream Cp or Wp promoters is the principal source of EBNA mRNAs. We carried out cDNA amplifications with oligonucleotide primer-probe combinations to determine whether Fp is ever active in an LCL environment. The results clearly showed that some LCLs express a Q/U/K-spliced EBNA1 mRNA in addition to the expected Cp/Wp-initiated transcripts; this seemed inconsistent with the concept of Cp/Wp and Fp as mutually exclusive promoters. Here we show that Fp is indeed silent in latency III cells but is activated at an early stage following the switch from latency III into the virus lytic cycle. Four pieces of evidence support this conclusion: (i) examples of coincident Cp/Wp and Fp usage in LCLs are restricted to those lines in which a small subpopulation of cells have spontaneously entered the lytic cycle; (ii) transcripts initiating from Fp can readily be demonstrated in spontaneously productive lines by S1 nuclease protection; (iii) the presence of Fp-initiated transcripts is not affected by acyclovir blockade of the late lytic cycle; and (iv) infection of latently infected LCLs with a recombinant vaccinia virus encoding the EBV immediate-early protein BZLF1, a transcriptional transactivator which normally initiates the lytic cycle, results in the appearance of the diagnostic Q/U/K-spliced transcripts.

Reaction time and movement time in children with a Developmental Coordination Disorder

The Test of Motor Impairment (TOMI) was used to select 12 children with a Developmental Coordination Disorder (DCD) and 12 age-matched controls. In an aiming task, movement latency, movement duration and its variability were significantly prolonged in the DCD group. In a coincidence timing version of the task, absolute timing error was significantly greater in the DCD group. The most robust chronometric effect for differentiating the two groups seemed to be the duration of movement when the target was small. Multiple regression showed that TOMI was a powerful indicator of movement duration.

General practitioners' reported knowledge about depression and dementia in elderly patients

Previous studies have shown that general practitioners often fail to detect dementia and depression in their elderly patients. The present study aimed to find out how much knowledge general practitioners have of these disorders. The knowledge of 36 general practitioners was assessed and it was found that they had a limited knowledge of the symptoms and signs of dementia and depression. Furthermore, almost 60% of the general practitioners did not know that Alzheimer's disease is the most common dementing disorder.

A strategy for development of computerized critical care decision support systems

It is not enough to merely manage medical information. It is difficult to justify the cost of hospital information systems (HIS) or intensive care unit (ICU) patient data management systems (PDMS) on this basis alone. The real benefit of an integrated HIS or PDMS is in decision support. Although there are a variety of HIS and ICU PDMS systems available there are few that provide ICU decision support. The HELP system at the LDS Hospital is an example of a HIS which provides decision support on many different levels. In the ICU there are decision support tools for antibiotic therapy, nutritional management, and management of mechanical ventilation. Computer protocols for the management of mechanical ventilation (respiratory evaluation, ventilation, oxygenation, weaning and extubation) in patients with adult respiratory distress syndrome ((ARDS) have already been developed and clinically validated at the LDS Hospital. These protocols utilize the bedside intensive care unit (ICU) computer terminal to prompt the clinical care team with therapeutic and diagnostic suggestions. The protocols (in paper flow diagram and computerized form) have been used for over 40,000 hours in more than 125 adult respiratory distress syndrome (ARDS) patients. The protocols controlled care for 94% of the time. The remainder of the time patient care was not protocol controlled was a result of the patient being in states not covered by current protocol logic (e.g. hemodynamic instability, or transport for X-Ray studies). 52 of these ARDS patients met extra corporal membrane oxygenation (ECMO) criteria. The survival of the ECMO criteria ARDS patients was 41%, four times that expected (9%) from historical data (p less than 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of computerized protocols for the management of arterial oxygenation in an intensive care unit

Computerized protocols were created to direct the management of arterial oxygenation in critically ill ICU patients and have now been applied routinely, 24 hours a day, in the care of 80 such patients. The protocols used routine clinical information to generate specific instructions for therapy. We evaluated 21,347 instructions by measuring how many were correct and how often they were followed by the clinical staff. Instructions were followed 63.9% of the time in the first 8 patients and 92.3% in the subsequent 72 patients. Instruction accuracy improved after the initial 8 patients, increasing from 71.5% of total instructions to 92.8%. Instruction inaccuracy was primarily caused by software errors and inaccurate and untimely entry of clinical data into the computer. Software errors decreased from 7.2% in the first 8 patients to 0.8% in subsequent patients, while data entry problems decreased from 7.5% to 4.2%. We also assessed compliance with the protocols in a subset of 12 patients (2637 instructions) as a function of 1) the mode of ventilatory support, 2) whether the instruction was to increase or decrease the intensity of therapy or to wait for an interval of time and 3) whether the instruction was 'correct' or 'incorrect'. The mode of ventilatory support did not affect compliance with protocol instructions. Instructions to wait were more likely to be followed than instructions to change therapy. Ninety-seven percent of the correct instructions were followed and 27% of the incorrect instructions were followed.(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge engineering using retrospective review of data: a useful technique or merely data dredging?

The process of extracting the knowledge or rules for medical decision making is not an easy task. One approach to knowledge engineering is to carefully review how decisions were made in the past with the goal of extracting the rules. The purpose of this project was to use previously collected data from ICU patients to derive the rules for the definition of hemodynamic stability. 97 ICU patients between 9/9/86 and 7/29/90 were included in the analysis. All of these patients had adult respiratory distress syndrome. Their mechanical ventilation was managed by a set of computerized protocols. We retrospectively searched the HELP system database for instructions that were not followed due to hemodynamic reasons. For each patient, we also chose one randomly selected therapy instruction which was followed to act as a control. For each instruction we then selected the corresponding hemodynamic data set. The data was then used in a stepwise logistic regression to determine the rules used for defining hemodynamic instability. We found that several of the hemodynamic parameters we had anticipated to be important were not even measured most of the time. The blood pressures and heart rate were almost identical between the hemodynamicly stable and unstable data sets. We conclude that the decision making process used by physicians has great variation, both between and within physicians. This makes knowledge engineering using retrospective techniques such as this prone to error and probably not very fruitful.

Surgical emphysema of the mediastinum as a consequence of attempted extraction of a third molar tooth using an air turbine drill

The use of air turbines for the removal of bone or the division of teeth is to be deprecated. Surgical emphysema of the neck and mediastinum as a direct result of the inappropriate use of an air turbine drill to remove an impacted third molar tooth may result in potentially life threatening complications.

The effects of ingesting polylactate or glucose polymer drinks during prolonged exercise

Five trained, fasted male cyclists rode a cycle ergometer three times at 50% of VO2max for 180 min. Using a balanced order, double-blind procedure, subjects were given either a solution containing polylactate (PL: 80% polylactate, 20% sodium lactate, in 7% solution with water), glucose polymer (GP: multidextrin in 7% solution with water), or control (C: water sweetened with aspartame) 5 min before exercise and at 20-min intervals during exercise. Venous blood samples were taken at rest and at 20-min intervals during exercise. In general, PL and GP rendered similar results except that pH and bicarbonate (HCO3-) were higher in PL. There were no differences between treatments in perceived exertion, sodium, potassium, chloride, lactate, heart rate, oxygen consumption, rectal temperature, or selected skin temperatures. These data show that polylactate may help maintain blood glucose and enhance blood buffering capacity during prolonged exercise and could be a useful component in an athletic fluid replacement beverage.

Induction of bcl-2 expression by Epstein-Barr virus latent membrane protein 1 protects infected B cells from programmed cell death

Epstein-Barr virus (EBV) not only induces growth transformation in human B lymphocytes, but has more recently been shown to enhance B cell survival under suboptimal conditions where growth is inhibited; both effects are mediated through the coordinate action of eight virus-coded latent proteins. The effect upon cell survival is best recognized in EBV-positive Burkitt's lymphoma cell lines where activation of full virus latent gene expression protects the cells from programmed cell death (apoptosis). Here we show by DNA transfection into human B cells that protection from apoptosis is conferred through expression of a single EBV latent protein, the latent membrane protein LMP 1. Furthermore, we demonstrate that LMP 1 mediates this effect by up-regulating expression of the cellular oncogene bcl-2. The interplay between EBV infection and expression of this cellular oncogene has important implications for virus persistence and for the pathogenesis of virus-associated malignant disease.

Activation of Epstein-Barr virus latent genes protects human B cells from death by apoptosis

Epstein-Barr virus (EBV), a human herpesvirus, establishes a persistent asymptomatic infection of the circulating B-lymphocyte pool. The mechanism of virus persistence is not understood but, given the limited lifespan of most B cells in vivo, it seems most likely that EBV-infected cells must gain access to the long-lived memory B-cell pool. Here we show in an in vitro system that EBV, through expression of the full set of eight virus-coded 'latent' proteins, can protect human B cells from programmed cell death (apoptosis), the deletion mechanism which normally restricts entry into memory. We have found that EBV-positive Burkitt's lymphoma (BL) cell clones retaining the original tumour cell phenotype and expressing only one of the virus latent proteins, the nuclear antigen EBNA 1, are extremely sensitive to apoptosis; in this respect they resemble the tumour's normal cell of origin found in the germinal centres of lymphoid tissue. By contrast, isogenic BL cell clones which have activated expression of all eight EBV latent proteins are resistant to the induction of apoptosis. The EBV latent proteins should therefore be seen not just as activators of B-cell proliferation but, perhaps more importantly, as mediators of enhanced B-cell survival.

Epstein-Barr virus (EBV)-associated lymphoproliferative disease in the SCID mouse model: implications for the pathogenesis of EBV-positive lymphomas in man

When human peripheral blood lymphocytes (PBLs) from Epstein-Barr virus (EBV)-seropositive donors are injected intraperitoneally into SCID mice, EBV+ B cell tumors develop within weeks. A preliminary report (Mosier, D. E., R. J. Gulizia, S. M. Baird, D. D. Richman, D. B. Wilson, R. I. Fox, and T. J. Kipps, 1989. Blood. 74(Suppl. 1):52a) has suggested that such tumors resemble the EBV-positive malignancy, Burkitt's lymphoma. The present work shows that generally the human (hu) PBL-SCID tumors are distinct from Burkitt's lymphoma and instead resemble lymphoblastoid cell lines (LCLs) generated by EBV-infection of normal B cells in vitro in terms of: (a) their cell surface phenotype, with expression of B cell activation antigens and adhesion molecules, (b) normal karyotype, and (c) viral phenotype, with expression of all the transformation-associated EBV latent proteins and, in a minority of cells, productive cycle antigens. Indeed, in vitro-transformed LCLs also grow when inoculated into SCID mice, the frequency of tumor outgrowth correlating with the in vitro growth phenotype of the LCL which is itself determined by the identity of the transforming virus (i.e., type 1 or type 2 EBV). Histologically the PBL-derived hu-SCID tumors resemble the EBV+ large cell lymphomas that develop in immuno-suppressed patients and, like the human tumors, often present at multiple sites as individual monoclonal or oligoclonal foci. The remarkable efficiency of tumor development in the hu-SCID model suggests that lymphomagenesis involves direct outgrowth of EBV-transformed B cells without requirement for secondary genetic changes, and that selection on the basis of cell growth rate alone is sufficient to explain the monoclonal/oligoclonal nature of tumor foci. EBV+ large cell lymphoma of the immunosuppressed may arise in a similar way.

The effects of shear stress on endothelial cell retention and function on expanded polytetrafluoroethylene

We evaluated the adherence of indium 111-radiolabeled endothelial cells to fibronectin-treated expanded polytetrafluoroethylene surfaces exposed to high (437 s-1) vs low (218 s-1) shear and the influence of shear on prostacyclin production. Canine jugular vein factor VIII-positive endothelial cells in passages 3 through 6 were incubated with 111Indium-oxine, and labeled cells were seeded onto fibronectin-treated expanded polytetrafluoroethylene patches. Patches with confluent cells were exposed to shear in a Weissenberg rheogoniometer for intervals ranging up to 60 minutes. Percent endothelial cell retention was determined by gamma counting of patches and media and by histologic evaluation. Prostacyclin production (tritiated radioimmunoassay of 6-keto-prostaglandin F1 alpha) was assayed on perfusing media. Results showed no differences in 6-keto-prostaglandin F1 alpha production between shear rates or time periods. Endothelial cell retention did not differ between the shear rates. Rotational shear caused persistent cell loss over time in either high- or low-shear conditions. This persistent cell loss in response to steady rotational shear differs from that in response to identical rates of pulsatile linear shear in our laboratory where cell loss approached zero after 15 minutes.

General practitioners' detection of depression and dementia in elderly patients

In a study of 11 general practitioners' detection of dementia and depression in 101 elderly patients it was found that general practitioners were more accurate in their detection of dementia than depression. The general practitioners did not identify 12 of the 15 patients assessed as depressed by a Diagnostic Interview for Depression, but their assessments of dementia corresponded quite well with the results of dementia tests. The general practitioners' knowledge of the symptoms and signs of dementia and depression was limited. If the patient talked to the general practitioner about feeling depressed, sad or irritable, the depression recognition rate increased.

Evidence for a general neurotic syndrome

Neurotic syndromes are defined by characteristic patterns of symptoms, but the validity of the distinction between one syndrome and another depends on associations between the syndromes and clinical history, or treatment response factors that are independent of the defining phenomena. In both a group of twin volunteers and a group of patients with panic disorder/agoraphobia, the lifetime experience of more than one diagnosis of a neurotic syndrome was common but there was no evidence of patterns of co-occurrence of diagnoses being associated with particular syndromes. Receiving a diagnosis was associated with abnormal scores on measures of neuroticism and locus of control, the extent of the abnormality increasing with the number of different diagnoses satisfied. It is argued that the concept of a general neurotic syndrome depends in part on the presence of such predisposing personality factors, and that reduction in this predisposition to neurosis should be the focus of treatment.

Twins: a test of the equal environments assumption

We asked a sample of 343 adult same-sex twin pairs a number of questions about the similarity of their social environment during childhood and early adolescence. A factor analysis of their responses indicated that their common environment was derived from two sources, one being similar treatment "imposed" upon them by their parents, the other being "elicited" by the twins' similar interests and behavior. Monozygotic (MZ) twins reported experiencing more similar "imposed" and "elicited" environments than dizygotic (DZ) twins. The extent of imposed similar treatment received during childhood and early adolescence was unrelated to either MZ or DZ twins' current behavioral similarity, as indicated by absolute intrapair differences in their Neuroticism, Anxiety, and Depression scores. Similar treatment imposed upon MZ twins on the basis of their zygosity alone is therefore not a threat to the validity of the twin method.

Diltiazem prevents hypertrophy progression, preserves systolic function, and normalises myocardial oxygen utilisation in the spontaneously hypertensive rat

The effects of diltiazem, a calcium channel blocker, and methyldopa, an adrenergic blocker, on left ventricular hypertrophy and left ventricular function were assessed in spontaneously hypertensive rats and Wistar-Kyoto controls. Diltiazem (30 mg.kg-1/day), methyldopa (400 mg.kg-1/day), or placebo were given with water for six months. Left ventricular function was studied in 12 month old animals using an isovolumetrically contracting heart preparation by measuring maximum developed pressure and myocardial oxygen consumption. Systolic blood pressure was reduced by both drugs but more so by methyldopa. Despite its lesser antihypertensive effect, diltiazem reduced heart to body weight ratios in the spontaneously hypertensive rat to a similar degree as methyldopa (3.4(0.2) and 3.4(0.1) compared with placebo 3.7(0.2), p less than 0.05). Maximum developed pressure increased with methyldopa and diltiazem compared with placebo (188(11) and 200(11) vs 166(11) mmHg, p less than 0.05). Myocardial oxygen consumption was lower in the spontaneously hypertensive rat receiving placebo than in the controls (22.8(3.2) vs 28.3(3.8) ml.min-1.100 g-1, p less than 0.05) and was significantly increased by diltiazem but not by methyldopa (27.9(0.4) vs 24.5(0.6) ml.min-1.100 g-1, p less than 0.05 and NS respectively vs the spontaneously hypertensive rat receiving placebo). Diltiazem and methyldopa normalised the isomyosin composition in the spontaneously hypertensive rat. Myocardial concentrations of energy related metabolites obtained at maximum developed pressure were not different between spontaneously hypertensive rats receiving placebo and controls. However, both diltiazem and methyldopa treated spontaneously hypertensive rats showed a significant reduction in adenosine triphosphate and phosphocreatine and a rise in inorganic phosphate.(ABSTRACT TRUNCATED AT 250 WORDS)

Diltiazem versus propranolol in essential hypertension: responses of rest and exercise blood pressure and effects on exercise capacity

Both beta-blocking and calcium channel-blocking drugs are being used with increasing frequency as initial therapy for essential hypertension. The present study was designed to compare the antihypertensive effects of a beta-blocking drug, propranolol, with a calcium channel-blocking drug, diltiazem, at rest and during upright bicycle exercise and to determine whether exercise capacity is altered by these therapies. Twenty-one patients with uncomplicated systemic hypertension and a diastolic blood pressure (BP) of 95 to 110 mm Hg without medication were randomly assigned to propranolol or diltiazem therapy in a double-blind manner. The total daily dosages were titrated as needed, from 160 to 480 mg of propranolol (mean 371 mg) and 120 to 360 mg of diltiazem (mean 307 mg) over 12 weeks, and the titrated dose was maintained for 4 additional weeks. Both drugs significantly reduced supine BP (from 149 +/- 14/101 +/- 4 to 136 +/- 17/89 +/- 10 mm Hg with propranolol and from 157 +/- 14/103 +/- 4 to 144 +/- 13/93 +/- 8 with diltiazem. Only diltiazem reduced BP during submaximal exercise, but both agents produced significant responses during maximal exercise. Diltiazem had no effect on maximal heart rate, exercise duration or O2 uptake, whereas propranolol reduced maximal VO2 from 27 +/- 6 to 22 +/- 6 ml/min/kg (p less than 0.01) and also shortened duration of exercise. Propranolol, despite its effects on heart rate, maintained the workload VO2 relation at submaximal loads, suggesting an increased oxygen delivery. However, these adaptive mechanisms appear to be insufficient during maximal effort.

LTB4 production and lysosomal enzyme release by rat alveolar macrophages: effects of phagocytosis, receptor binding, and ionophore stimulation

We have previously shown that the predominant lipoxygenase product of arachidonic acid metabolism in rabbit alveolar macrophages is leukotriene (LT) B4. LTB4 was not detectable in normal unstimulated rabbit macrophages, but its production was increased following calcium ionophore A23187 stimulation, especially after in vivo activation of the immune system. In the present study, we describe that (a) rat alveolar macrophages produced LTB4 in response to natural, biological stimuli such as binding of Fc receptors and complement receptors, as well as zymosan phagocytosis and ionophore stimulation. In contrast, binding of lectin receptors such as concanavalin A and phytohemagglutinin failed to elicit significant increase of LTB4. (b) The predominant LT that was produced was LTB4 regardless of the type of stimulus. This pattern is similar to that of rabbit lung macrophages, but rat alveolar macrophages released higher quantities of LTB4, which can be easily quantitated by high-performance liquid chromatography (HPLC). (c) Phorbol myristate acetate by itself was a weak agonist for LTB4 release. Yet, in combination with a low dose of calcium ionophore A23187 it resulted in LTB4 production. (d) There was a general correlation between release of LTB4 and lysosomal enzymes. In other words, the stimulus that is effective for eliciting enzyme release was usually also effective in causing LTB4 production. (e) A considerable proportion of the LTB4 produced was retained intracellularly. This phenomenon was especially pronounced when zymosan was used as stimulus. (f) Despite the parallelism between LTB4 production and lysosomal enzyme release, the former probably does not regulate the latter. The time courses of their release are dissimilar, and nordihydroguaiaretic acid fails to inhibit lysosomal enzyme release by a dose markedly inhibiting LTB release. (g) Contrary to rabbit lung macrophages rat lung macrophages showed a predominance of lipoxygenase pathway over cyclooxygenase pathway following zymosan ingestion. However, macrophages from both species produced mainly cyclooxygenase products in response to exogenous arachidonic acid.

A transcriptional terminator is a novel element of the promoter of the mouse ribosomal RNA gene

Sequences flanking residue-168 of the mouse rRNA gene are essential to direct efficient transcription in transfected cells and are stimulatory in vitro on closed circular templates. This promoter domain evidently functions by the unprecedented mechanism of terminating polymerase I-directed transcripts. It inhibits transcripts from reading into the initiation region, acting cotranscriptionally to end these RNAs at residue--182 and release them from the template. Most likely, polymerases on tandem genomic rRNA genes are not released upon completing each 40-47S transcript, but traverse the entire spacer to the next promoter-terminator, where they are made available and positioned to favor reinitiation. Through such polymerase recycling, plus the binding of free polymerase, the rDNA promoters could achieve their characteristically high level of transcription.

Heavy charged particle therapy of bone and soft tissue sarcoma. A phase I-II trial of the University of California Lawrence Berkeley Laboratory and the Northern California Oncology Group

At the University of California Lawrence Berkeley Laboratory and the Northern California Oncology Group, a preliminary study of heavy charged particle radiotherapy in soft tissue and bone sarcoma has been carried out. Fifty-two patients with bone or soft tissue tumors were treated wholly or in part with heavy charged particles from 1978 to 1985. Eleven patients, considered inevaluable for purposes of this analysis, received less than 50 Gray-equivalents (GyE) because of the following: progressive disease (three patients); palliative treatment due to recurrent disease after previous radiation therapy (three patients); or since they were part of preliminary studies of relative biological effectiveness (RBE) (five patients). Forty-one patients received from 50 to 78.5 GyE, with a mean of 65 GyE. They had an average of 23 months follow-up, ranging from 4 to 78 months. In patients with paraspinal chondrosarcoma 9 of 11 had local control, with a mean follow-up time of 32 months. In the remaining patients with other histologies, 19 of 30 were controlled within the irradiated area, with a mean follow-up time of 20 months. Serious complications were encountered in the CNS (four patients), in the bowel (one patient), and in bone (one patient). Heavy charged particle radiotherapy appears to be of value in treating bone or soft tissue sarcoma; further trials are planned.