Comparison of Contemporary Risk Scores in All Groups of Pulmonary Hypertension: A Pulmonary Vascular Research Institute GoDeep Meta-Registry Analysis

BACKGROUND

Pulmonary hypertension (PH) is a heterogeneous disease with a poor prognosis. Accurate risk stratification is essential for guiding treatment decisions in pulmonary arterial hypertension (PAH). Although various risk models have been developed for PAH, their comparative prognostic potential requires further exploration. Additionally, the applicability of risk scores in PH groups beyond group 1 remains to be investigated.

RESEARCH QUESTION

Are risk scores originally developed for PAH predictive in PH groups 1 through 4?

STUDY DESIGN AND METHODS

We conducted a comprehensive analysis of outcomes among patients with incident PH enrolled in the multicenter worldwide Pulmonary Vascular Research Institute GoDeep meta-registry. Analyses were performed across PH groups 1 through 4 and further subgroups to evaluate the predictive value of PAH risk scores, including REVEAL Lite 2, REVEAL 2.0, ESC/ERS 2022, COMPERA 3-strata, and COMPERA 4-strata.

RESULTS

Eight thousand five hundred sixty-five patients were included in the study, of whom 3,537 patients were assigned to group 1 PH, whereas 1,807 patients, 1,635 patients, and 1,586 patients were assigned to group 2 PH, group 3 PH, and group 4 PH, respectively. Pulmonary hemodynamics were impaired with median mean pulmonary arterial pressure of 42 mm Hg (33-52 mm Hg) and pulmonary vascular resistance of 7 WU (4-11 WU). All risk scores were prognostic in the entire PH population and in each of the PH groups 1 through 4. The REVEAL scores, when used as continuous prediction models, demonstrated the highest statistical prognostic power and granularity; the COMPERA 4-strata risk score provided subdifferentiation of the intermediate-risk group. Similar results were obtained when separately analyzing various subgroups (PH subgroups 1.1, 1.4.1, and 1.4.4; PH subgroups 3.1 and 3.2; group 2 with isolated postcapillary PH vs combined precapillary and postcapillary PH; patients of all groups with concomitant cardiac comorbidities; and severe [> 5 WU] vs nonsevere PH).

INTERPRETATION

This comprehensive study with real-world data from 15 PH centers showed that PAH-designed risk scores possess predictive power in a large PH cohort, whether considered as common to the group or calculated separately for each PH group (1-4) and various subgroups.

Real-world evidence to advance knowledge in pulmonary hypertension: Status, challenges, and opportunities. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative's Real-world Evidence Working Group

This manuscript on real-world evidence (RWE) in pulmonary hypertension (PH) incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative Real-World Evidence Working Group. We aim to strengthen the research community's understanding of RWE in PH to facilitate clinical research advances and ultimately improve patient care. Herein, we review real-world data (RWD) sources, discuss challenges and opportunities when using RWD sources to study PH populations, and identify resources needed to support the generation of meaningful RWE for the global PH community.

International survey of antibiotic dosing and monitoring in adult intensive care units

BACKGROUND

In recent years, numerous dosing studies have been conducted to optimize therapeutic antibiotic exposures in patients with serious infections. These studies have led to the inclusion of dose optimization recommendations in international clinical practice guidelines. The last international survey describing dosing, administration and monitoring of commonly prescribed antibiotics for critically ill patients was published in 2015 (ADMIN-ICU 2015). This study aimed to describe the evolution of practice since this time.

METHODS

A cross-sectional international survey distributed through professional societies and networks was used to obtain information on practices used in the dosing, administration and monitoring of vancomycin, piperacillin/tazobactam, meropenem and aminoglycosides.

RESULTS

A total of 538 respondents (71% physicians and 29% pharmacists) from 409 hospitals in 45 countries completed the survey. Vancomycin was mostly administered as an intermittent infusion, and loading doses were used by 74% of respondents with 25 mg/kg and 20 mg/kg the most favoured doses for intermittent and continuous infusions, respectively. Piperacillin/tazobactam and meropenem were most frequently administered as an extended infusion (42% and 51%, respectively). Therapeutic drug monitoring was undertaken by 90%, 82%, 43%, and 39% of respondents for vancomycin, aminoglycosides, piperacillin/tazobactam, and meropenem, respectively, and was more frequently performed in high-income countries. Respondents rarely used dosing software to guide therapy in clinical practice and was most frequently used with vancomycin (11%).

CONCLUSIONS

We observed numerous changes in practice since the ADMIN-ICU 2015 survey was conducted. Beta-lactams are more commonly administered as extended infusions, and therapeutic drug monitoring use has increased, which align with emerging evidence.

Recommendations for the diagnosis and management of vaccine-induced immune thrombotic thrombocytopenia

There have recently been safety concerns regarding an increased risk of vaccine-induced immune thrombotic thrombocytopenia (VITT) following administration of SARS-CoV-2 adenoviral vector vaccines. The Southern African Society of Thrombosis and Haemostasis reviewed the emerging literature on this idiosyncratic complication. A draft document was produced and revised by consensus agreement by a panel of professionals from various specialties. The recommendations were adjudicated by independent international experts to avoid local bias. We present concise, practical guidelines for the clinical management of VITT.

Haemodynamic definitions and updated clinical classification of pulmonary hypertension

Since the 1st World Symposium on Pulmonary Hypertension (WSPH) in 1973, pulmonary hypertension (PH) has been arbitrarily defined as mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest, measured by right heart catheterisation. Recent data from normal subjects has shown that normal mPAP was 14.0±3.3 mmHg. Two standard deviations above this mean value would suggest mPAP >20 mmHg as above the upper limit of normal (above the 97.5th percentile). This definition is no longer arbitrary, but based on a scientific approach. However, this abnormal elevation of mPAP is not sufficient to define pulmonary vascular disease as it can be due to an increase in cardiac output or pulmonary arterial wedge pressure. Thus, this 6th WSPH Task Force proposes to include pulmonary vascular resistance ≥3 Wood Units in the definition of all forms of pre-capillary PH associated with mPAP >20 mmHg. Prospective trials are required to determine whether this PH population might benefit from specific management.

Regarding clinical classification, the main Task Force changes were the inclusion in group 1 of a subgroup “pulmonary arterial hypertension (PAH) long-term responders to calcium channel blockers”, due to the specific prognostic and management of these patients, and a subgroup “PAH with overt features of venous/capillaries (pulmonary veno-occlusive disease/pulmonary capillary haemangiomatosis) involvement”, due to evidence suggesting a continuum between arterial, capillary and vein involvement in PAH.

State of the art and research perspectives of haemodynamic definitions and clinical classification of pulmonary hypertensionhttp://ow.ly/TJeR30mgWKj

Haemodynamic definitions and updated clinical classification of pulmonary hypertension

Since the 1st World Symposium on Pulmonary Hypertension (WSPH) in 1973, pulmonary hypertension (PH) has been arbitrarily defined as mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest, measured by right heart catheterisation. Recent data from normal subjects has shown that normal mPAP was 14.0±3.3 mmHg. Two standard deviations above this mean value would suggest mPAP >20 mmHg as above the upper limit of normal (above the 97.5th percentile). This definition is no longer arbitrary, but based on a scientific approach. However, this abnormal elevation of mPAP is not sufficient to define pulmonary vascular disease as it can be due to an increase in cardiac output or pulmonary arterial wedge pressure. Thus, this 6th WSPH Task Force proposes to include pulmonary vascular resistance ≥3 Wood Units in the definition of all forms of pre-capillary PH associated with mPAP >20 mmHg. Prospective trials are required to determine whether this PH population might benefit from specific management.Regarding clinical classification, the main Task Force changes were the inclusion in group 1 of a subgroup "pulmonary arterial hypertension (PAH) long-term responders to calcium channel blockers", due to the specific prognostic and management of these patients, and a subgroup "PAH with overt features of venous/capillaries (pulmonary veno-occlusive disease/pulmonary capillary haemangiomatosis) involvement", due to evidence suggesting a continuum between arterial, capillary and vein involvement in PAH.

20p11 deletion in a female child with panhypopituitarism, cleft lip and palate, dysmorphic facial features, global developmental delay and seizure disorder

Deletions of 20p are rare with the majority of reported cases involving individuals with 20p12 deletions associated with Alagille syndrome. We report on a child with a de novo mosaic 20p11 deletion who presents with panhypopituitarism; hypoplastic pituitary gland and ectopic posterior pituitary gland on MRI of the brain; cleft lip and palate; kyphosis with anterior beaking of L1 and L2 vertebral bodies; pulmonic stenosis; dysmorphic facial features including flat nasal bridge, hypoplastic premaxilla, hypotelorism, preauricular pit, and cupped ears; seizure disorder; variable muscle tone; and global developmental delay. Array comparative genomic hybridization revealed this deletion to be approximately 5.4 Mb in size, containing 35 genes. Previously, an infant with 20p11.22 deletion who had panhypopituitarism, craniofacial, and genital abnormalities was reported, but the precise parameters of that deletion are unavailable. Several other reported cases of 20p11 deletions also have phenotypic overlap with our case. The similarities in clinical features of these patients suggest that the genes at 20p11 have a critical role in development of midline brain structures.

Examining communication and assertiveness as predictors of condom use: implications for HIV prevention

The current study explored the relationship between communication and assertiveness in general and sexual contexts and examined each construct's differential ability to predict reported condom use among college students. The results suggest that the constructs are positively related to each other, but general communication does not predict sexual assertiveness. Although sexual assertiveness is a better predictor of condom use than general assertiveness, general communication, and sexual communication, it needs to be considered within the context of other variables (e.g., normative beliefs regarding condom use). HIV prevention programs and models of health behavior should incorporate individual characteristics such as sexual assertiveness. The results of this study suggest that sexual assertiveness, social norm perceptions of condom use, self-efficacy for HIV prevention, and condom attitudes are among the critical variables that should be examined in an integrated model of sexual health behavior.

Personality correlates of glycemic control in type 2 diabetes

OBJECTIVE

To determine whether traits of normal personality are associated with variations in glycemic control in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A longitudinal cohort study was conducted using data from 105 type 2 diabetic patients in a clinical trial of a stress management intervention. Before treatment assignment, patients completed the NEO Personality Inventory, Revised, which is a questionnaire inventory measuring 5 major domains of normal personality and 30 important traits that define these domains. Glycemic control was assessed by measures of HbA1c and average blood glucose levels based on 7 days of self-monitoring at baseline and at 6 and 12 months. Relationships between personality traits and measures of glycemic control were examined by correlation and linear regression models that were adjusted for age, sex, race, duration of diabetes, medication status, and experimental treatment.

RESULTS

Lower average blood glucose values at baseline were associated with higher scores for the personality domain of neuroticism and several specific traits including anxiety, angry hostility depression, self-consciousness, and vulnerability but were associated with lower scores for the trait of altruism. Results were similar for HbA1c but were not as strong. Follow-up results were similar but were less consistent.

CONCLUSIONS

Personality traits may offer new insights into variations in glycemic control in patients with type 2 diabetes undergoing standard management. The relative tendency to experience fewer negative emotions and to focus on the needs of others instead of oneself could prove to be a risk factor for poor glycemic control.

Recent developments in tritium incorporation for radiotracer studies

The essential nature of rapid radiotracer synthesis very early in drug discovery programs has driven the need for better and more varied tritium incorporation methods. This review presents a summary of recent advances for tritium introduction via tritiated water, tritium gas, complex tritides, and a range of recently improved tritiation reagents. Access to a wider range of tritiated reagents (for tritioacetylation, tritioformylation, methylation, etc.) and commercial manifolds for the transfer and use of tritium gas is also discussed.

Eating habits of children with autism

Autism is a developmental disorder characterized by severe deficits in social interaction and communication, as well as by stereotyped and repetitive behaviors. Children with autism frequently have significant eating difficulties with highly restricted range of food choices. Eating habits and patterns are often unusual and have an impact on family life. The purpose of this article was to review pertinent information regarding this complex developmental disorder and describe a recent study based on a parent survey of feeding patterns in children with autism to give a new perspective for both parents and professionals.

Inhibition of protein synthesis by didemnin B: how EF-1alpha mediates inhibition of translocation

The antineoplastic cyclic depsipeptide didemnin B (DB) inhibits protein synthesis in cells and in vitro. The stage at which DB inhibits protein synthesis in cells is not known, although dehydrodidemnin B arrests translation at the stage of polypeptide elongation. Inhibition of protein synthesis by DB in vitro also occurs at the elongation stage, and it was shown previously that DB prevents EF-2-dependent translocation in partial reaction models of protein synthesis. This inhibition of translocation displays an absolute requirement for EF-1alpha; however, the dependence upon EF-1alpha was previously unexplained. It is shown here that DB binds only weakly to EF-1alpha/GTP in solution, but binds to ribosome. EF-1alpha complexes with a dissociation constant K(d) = 4 microM. Thus, the inhibition of protein synthesis by DB appears to involve an interaction with both EF-1alpha and ribosomes in which all three components are required. Using diphtheria toxin-mediated ADP-ribosylation to assay for EF-2, it is demonstrated that DB blocks EF-2 binding to pre-translocative ribosome.EF-1alpha complexes, thus preventing ribosomal translocation. Based on this model for protein synthesis inhibition by DB, and the proposed mechanism of action of fusidic acid, evidence is presented in support of the Grasmuk model for EF-1alpha function in which this elongation factor does not fully depart the ribosome during polypeptide elongation.

[3H]Azidodantrolene: synthesis and use in identification of a putative skeletal muscle dantrolene binding site in sarcoplasmic reticulum

Dantrolene sodium is a medically important hydantoin derivative that interferes with release of Ca2+ from intracellular stores of skeletal muscle by an unknown mechanism. Identification of the molecular target of dantrolene would greatly aid in understanding both the mechanism of action of the drug and the dynamics of intracellular Ca2+ release in muscle. [3H]Azidodantrolene was designed and synthesized as a photoaffinity analogue in order to identify a putative dantrolene receptor in skeletal muscle. Introduction of 1 mole-atom of tritium into aldehyde 5b was required during radioligand synthesis in order to ensure high enough specific activity for detection of photo-cross-linked proteins by fluorographic methods. This was accomplished by reduction of ester 3 with custom synthesized, 100% tritium-labeled lithium triethylborotritide, followed by oxidation to 5b by manganese(IV) oxide. Compound 6b was demonstrated to be >/=95% tritium-labeled at the imine position by NMR spectroscopy, and the specific radioactivity of [3H]azidodantrolene sodium was empirically determined by HPLC and liquid scintillation counting to be 24.4 Ci/mmol, approximately 85% of theoretical maximum. [3H]Azidodantrolene was found to be pharmacologically active in ligand-receptor binding studies with skeletal muscle sarcoplasmic reticulum membranes. Photo-cross-linking experiments analyzed by SDS-PAGE and tritium fluorography have identified a approximately 160-kDa specifically labeled protein as the putative, intracellular, skeletal muscle dantrolene receptor. This photolabeled protein comigrates with a protein in Western blots immunologically cross-reactive to a polyclonal anti-rabbit skeletal muscle ryanodine receptor antibody. Thus, the putative dantrolene receptor may be related to the skeletal muscle ryanodine receptor.

Case reports in autism: issues in diagnosis and treatment

Autism is a relatively common developmental disorder characterized by pervasive impairments in communication and social interaction as well as restricted interests and repetitive behaviors. Two case reports are presented to illustrate important aspects of diagnosis and treatment. Early clinical diagnosis is essential so that appropriate intervention can be implemented. A multidisciplinary approach to treatment is recommended due to the impact of autism on many aspects of behavior and development.

Personality predictors of mood related to dieting

The clinical utility of a model of normal emotional functioning (vs. psychopathology) and the moderating effects of neuroticism (N) and extraversion (E) on mood were examined during a 6-week weight-loss trial. Participants were 40 obese women who completed measures of negative affect (NA) and positive affect (PA) weekly during the diet and measures of anxiety and depression (Beck Depression Inventory [BDI]) at pre-, mid-, and postdiet. Results indicated that (a) average NA and PA were each uniquely related to postdiet BDI scores, (b) N was significantly related to NA during the diet and postdiet BDI scores, and (c) N and E interacted to predict PA during the diet. The results suggest that assessment of personality and normal mood variation may be useful additions to weight-loss intervention and research.

Greig cephalopolysyndactyly syndrome: altered phenotype of a microdeletion syndrome due to the presence of a cytogenetic abnormality

A male had several features of Greig cephalopolysyndactyly syndrome (GCPS) and significant developmental delay. He was found to have a de novo chromosomal deletion of chromosome no. 7 involving p13; this resulted in loss of the zinc finger gene, GLI3, which is the candidate gene in this syndrome. Modification of the CGPS phenotype in a sporadic case emphasizes the importance of searching for a chromosomal origin of this autosomal dominant disorder. Detection of a chromosomal deletion in these patients may be associated with a poor prognosis from the standpoint of cognitive development, and the potential for other structural abnormalities not normally associated with GCPS.

Tritium NMR studies of the human carbonic anhydrase I-benzenesulfonamide complex

Tritium NMR spectroscopy has been used to examine the complex formed by [4-3H]benzenesulfon-amide and human carbonic anhydrase I. The results show that in solution the inhibitor forms a 1:1 complex with the enzyme. A 100-spin computational model of the system, constructed with reference to crystallographic results, was used to interpret tritium relaxation behavior and 3H{1H} NOEs. The analysis shows that the rate of dissociation of the enzyme-sulfonamide complex is 0.35 s-1 and that the aromatic ring of the inhibitor undergoes rapid rotation while complexed.

A male with fetal valproate syndrome and autism

Fetal valproate syndrome (FVS) is characterized by minor craniofacial anomalies, major organ malformations, and developmental delay. We report on a patient who has a clinical phenotype compatible with both FVS and autism. The presence of an autistic disorder in a previously reported case of FVS and similar findings in our patient suggest that a relation between this known teratogen and autism may exist.

Illicit intravenous drug use in Johannesburg--medical complications and prevalence of HIV infection

OBJECTIVE

To describe the magnitude of the problem of abuse by self-injection of dipianone HCl/cyclizine HCl (Wellconal) and to document the associated morbidity, mortality and prevalence of HIV infection.

DESIGN

We conducted a retrospective analysis of 121 admissions of 86 patients who were current intravenous Wellconal abusers and presented to Johannesburg and J G Strijdom Hospitals over an 18-month period. Case records were analysed in respect of age, sex, median hospital stay, complications, HIV antibody status and eventual outcome.

MAIN OUTCOME MEASURES

Age, sex, median hospital stay, complications, HIV antibody status and eventual outcome.

RESULTS

Complications of Wellconal abuse occurred in young adults (median age 24 years) with an approximately equal gender distribution. Opiate overdose was the most frequent presenting diagnosis (32%), followed by right-sided endocarditis (20%) and deep-vein thrombosis (12%). A wide variety of complications accounted for the remaining 36%. A 2% HIV antibody positivity rate was found, which is substantially lower than that encountered in intravenous drug abusers in other parts of the world. Seventy-eight per cent of patients completed therapy successfully, but 19% left hospital prematurely against medical advice. There was a mortality rate of 3%.

CONCLUSIONS

While the prevalence of Wellconal abuse in the broader South African community is unknown, our study draws attention to the extent of the problem in Johannesburg.

Case study: cross-gender preoccupations with two male children with autism

Persons with autism frequently exhibit circumscribed interests and unusual preoccupations. In this case study, two young males with autism are presented who have preoccupations with feminine gender-stereotyped activities and objects. These types of preoccupations in children with autism have not been reported in the literature, but may be more prevalent than realized due to parental underreporting given the negative stigma associated with feminine interests in young boys. The development of gender identity in young children with autism has rarely been addressed in the literature. It seems unlikely that these two cases can be categorized as gender identity disorders. Understanding these preoccupations in the context of autism rather than focusing on the gender identity issues has important implications for treatment. These cases point to the need for further study of the complex interplay of environmental and neurobiologic factors affecting gender identity roles and preoccupations in autism.

Animal models provide insight into psychosomatic factors in diabetes

OBJECTIVE

To review the literature regarding the use of animal models in research addressing psychosomatic aspects of diabetes.

METHOD

We examine the key findings in animal model vs. human research in the area of stress and diabetes. Previous research has suggested that stress is a potential contributor to chronic hyperglycemia in diabetes. Stress affects metabolic activity via the stimulation of a variety of hormones that can result in elevated blood glucose levels. In patients with diabetes, due to a relative or absolute lack of insulin, stress-induced increases in glucose cannot be properly metabolized. Additionally, regulation of these stress hormones may be abnormal in diabetes.

RESULTS

Human studies on the role of stress in the onset and course of type II diabetes are few and are limited by the constraints and logistics of examining life stress in humans. However, animal research allows for tight experimental control and the manipulation of factors that may contribute to the development and/or course of diabetes, such as stress, eating behavior, the nutrient content of food, and physical activity. Disease processes can be examined at a mechanistic level in animals which is typically limited in human research.

CONCLUSIONS

There is a large body of animal work to support the notion that stress reliably produces hyperglycemia in type II diabetes. Furthermore, there is evidence that the autonomic nervous system plays a role in the pathophysiology of this condition in both animals and humans. Examination of eating behavior and nutrient content of food in animal models of diabetes has shed light on the role of these factors in the development of diabetes, as well as obesity. Finally, genetic research using animal models of diabetes will provide new directions for research in humans to delineate the genetic contribution to the development of diabetes.

Applications of tritium NMR to macromolecules: a study of two nucleic acid molecules

We have tritium labeled two nucleic acid molecules, an 8 kDa DNA oligomer and a 20 kDa 'hammer-head' RNA for tritium NMR investigations. The DNA sequence studied has been previously used in homonuclear studies of DNA-bound water molecules and tritium NMR was expected to facilitate these investigations by eliminating the need to suppress the water resonance in tritium-detected 3H-1H NOESY experiments. We observed the anticipated through-space interactions found in B-form DNA in the NOESY experiments and an unexpected 'antiphase' cross-peak at the water frequency. T1 measurements on the tritiated DNA molecule indicated that relaxation rates were also accelerated for tritium and protons. Tritium NMR spectra of the hammerhead RNA molecule indicated conformational dynamics in the conserved region of the molecule in the absence of Mg2+ and spermine, two components necessary for cleavage. The dynamics were also investigated by 15N-correlated 1H spectroscopy and persisted after the addition of Mg2+ and spermine.

Vitamin retention in cook/chill and cook/hot-hold hospital food-services

The vitamins with the greatest losses during hot-holding of food (> 10% after 2 hours) are vitamin C, folate, and vitamin B-6; retinol, thiamin, riboflavin, and niacin appear to be relatively stable. The 66 studies reviewed in this article give inadequate information on the losses of many other vitamins. In cook/chill food-services, substantial losses of sensitive vitamins occur during each of the chilling, storage, and reheating stages. Different reheating methods have similar effects on the amount of vitamin retention. Losses of vitamin C and folate can be greater than 30% when food is reheated after storage for 24 hours at 3 degrees C. Current research indicates that under normal operating conditions, with hot-holding limited to less than 90 minutes, vitamin retention is better in a conventional food-service than in a cook/chill system.

Structure and dynamics of tosylchymotrypsin at pH 7 examined by tritium NMR spectroscopy

3H-NMR spectroscopy of specifically tritiated and tritiated/deuterated derivatives of tosylchymotrypsin has been used to examine the behavior of the tosyl group in this protein at pH 7. The presence of several tritiated isotopomers complicates analysis of experiments and extensive computer simulations of T1 relaxation, line widths, and various nuclear Overhauser experiments for the collection of tritiated species present in the samples were used to the interpret the observations made. These analyses suggests that the tosyl group of tosylchymotrypsin at pH 7 is largely retained within the substrate specificity pocket observed in the crystal structure. This outcome is in strong contrast to the situation observed at pH 4, where the tosyl group is mobile enough to be found outside the specificity pocket an appreciable fraction of the time, and may be the result of protein association at pH 7.

Use of nuclear magnetic resonance in probing ligand-macromolecule interactions

Nuclear magnetic resonance techniques can be used to study ligand-macromolecule interactions under a wide variety of conditions. There are a number of different approaches, which are generally applicable under different conditions of exchange rate and binding constant. In the tight binding limit direct structural studies using NOE are possible using labeled ligand (13C, 15N) and/or labeled macromolecule. In the intermediate exchange regime, line broadening complicates the analysis of bound conformations of ligands. However, a good deal of information can be obtained about the binding kinetics and about the number and nature of binding modes when several are present. In such cases it is often best to use an NMR active nucleus which can be directly detected, with high sensitivity. Tritium has good characteristics in this respect, and has been effective in a number of cases. In the fast exchange limit it is often best to use the rapid dissociation of the ligand to transfer structural information from the bound form to the free, where it can be sensitively and selectively detected, often by direct observation of 1H values. There are a number of conditions on the binding kinetics which must be met, and systems with multiple binding sites generally cannot be analyzed. The large number of different NMR approaches which can be used, often only under special conditions of exchange, complicates planning of NMR studies of ligand-macromolecule interactions. However, once the characteristics of binding affinity and exchange rate have been determined, it is usually possible to apply NMR spectroscopy to obtain information about the binding. The instrumental demands for carrying out ligand-macromolecule interactions are generally not more than those required for studies of the macromolecules alone.

[2-3H]ATP synthesis and 3H NMR spectroscopy of enzyme-nucleotide complexes: ADP and ADP.Vi bound to myosin subfragment 1

The synthesis of [2-3H]ATP with specific activity high enough to use for 3H NMR spectroscopy at micromolar concentrations was accomplished by tritiodehalogenation of 2-Br-ATP. ATP with greater than 80% substitution at the 2-position and negligible tritium levels at other positions had a single 3H NMR peak at 8.20 ppm in 1D spectra obtained at 533 MHz. This result enables the application of tritium NMR spectroscopy to ATP utilizing enzymes. The proteolytic fragment of skeletal muscle myosin, called S1, consists of a heavy chain (95 kDa) and one alkali light chain (16 or 21 kDa) complex that retains myosin ATPase activity. In the presence of Mg2+, S1 converts [2-3H]ATP to [2-3H]ADP and the complex S1.Mg[2-3H]ADP has ADP bound in the active site. At 0 degrees C, 1D 3H NMR spectra of S1.Mg[2-3H]ADP have two broadened peaks shifted 0.55 and 0.90 ppm upfield from the peak due to free [2-3H]ADP. Spectra with good signal-to-noise for 0.10 mM S1.Mg[2-3H]ADP were obtained in 180 min. The magnitude of the chemical shift caused by binding is consistent with the presence of an aromatic side chain being in the active site. Spectra were the same for S1 with either of the alkali light chains present, suggesting that the alkali light chains do not interact differently with the active site. The two broad peaks appear to be due to the two conformations of S1 that have been observed previously by other techniques. Raising the temperature to 20 degrees C causes small changes in the chemical shifts, narrows the peak widths from 150 to 80 Hz, and increases the relative area under the more upfield peak. Addition of orthovanadate (Vi) to produce S1.Mg[2-2H]ADP.Vi shifts both peaks slightly more upfield without changing their widths or relative areas.

Personality and health: advantages and limitations of the five-factor model

Interest in the association between personality characteristics and physical health has been renewed in recent years. Theory and research in this area has also been complicated by conceptual and methodological limitations. The present article briefly reviews this literature and discusses the advantages and limitations of the five-factor model of personality as an integrating framework for studies of personality and health. The model has already been fruitfully applied in several contexts, and more possibilities exist. Although it has some potential limitations, the application of the five-factor model--as well as other aspects of current personality theory and research--is likely to facilitate progress in the study of how personality influences health.

Coping processes as mediators of the relationship between hardiness and health

Hardiness has been hypothesized to moderate the impact of stress on health by influencing coping responses, but little attention has been focused upon these associations. This study examined the relationship among hardiness, coping, and illness while attending to recent criticisms of the hardiness literature including the potential overlap with neuroticism, whether hardiness is a unitary construct, and the predominant use of male samples. Hardiness was found to be positively related to adaptive coping variables and negatively related to maladaptive coping variables. Problem-focused, support-seeking, and avoidant coping were found to mediate the hardiness-illness relationship. Although these hardiness-coping relationships were partially independent of the influence of neuroticism, the relationship of both coping and hardiness with self-reported illness appeared to result from the common influence of neuroticism. Consistent with previous research, the commitment and control components correlated most consistently with coping variables, and predicted hardiness effects were most consistently demonstrated for males.

Tritium NMR spectroscopy of ligand binding to maltose-binding protein

Tritium-labeled alpha- and beta-maltodextrins have been used to study their complexes with maltose-binding protein (MBP), a 40-kDa bacterial protein. Five substrates, from maltose to maltohexaose, were labeled at their reducing ends and their binding studied. Tritium NMR spectroscopy of the labeled sugars showed large upfield chemical shift changes upon binding and strong anomeric specificity. At 10 degrees C, MBP bound alpha-maltose with 2.7 +/- 0.5-fold higher affinity than beta-maltose, and, for longer maltodextrins, the ratio of affinities (KD beta/KD alpha) was even larger (between 10 and 30). The maximum chemical shift change was 2.2 ppm, suggesting that the reducing end of bound alpha-maltodextrin makes close contact with an aromatic residue in the MBP-binding site. Experiments with maltotriose (and longer maltodextrins) also revealed the presence of two bound beta-maltotriose resonances in rapid exchange. We interpret these two resonances as arising from two distinct sugar-protein complexes. In one complex, the beta-maltodextrin is bound by its reducing end, and, in the other complex, the beta-maltodextrin is bound by the middle glucose residue(s). This interpretation also suggests how MBP is able to bind both linear and circular maltodextrins.

Relationship of the children's form of the Rosenzweig Picture-Frustration Study to children's behavior, gender, and fantasies

To examine the validity of the Children's Form of the Picture-Frustration (P-F) Study, the instrument was administered to 245 children in Grades 1 through 6. Children were also administered the Make A Picture Story (MAPS) and the Response Hierarchy Measure. Teachers rated children's aggression on the Conners Teacher Rating Scale. Hostile responses on the P-F Study were related to self-reported verbal and physical aggression in conflict situations but were unrelated to teachers' ratings of aggressive behavior. Hostile responses were exhibited more often by boys than girls. Responses on the measure were related to children's fantasy patterns. Results supported the validity of the P-F Study as a measure of children's thought content in response to frustration.

3H nuclear magnetic resonance study of anaerobic glycolysis in packed erythrocytes

The utility and power of 3H NMR spectroscopy as a technique for monitoring biological systems in vivo is illustrated with glucose metabolism in erythrocytes. Use of C-1-tritiated glucose allowed us to monitor the disappearance of the alpha and beta tritons, with the production of lactate and 1H3HO (HTO), as well as some intermediates. Spin lattice relaxation times (T1) were measured to avoid T1 distortion of the spectral intensities. Detection of the formation of 1 mM tritiated water in the presence of 110 M H2O protons and deuterons allows the eventual fate of the label in the pentose shunt to be observed in vivo.

Variability of responses within the aggression categories on the Rosenzweig Picture-Frustration Study, Children's Form

This study examined whether the procedure for combining scores to make aggression categories on the Children's Form of the Picture-Frustration Study is psychometrically sound. Subjects were 245 children from Grades 1 through 6. Their responses were rated according to the 11 kinds of responses defined in the manual (Rosenzweig, 1978c). Results indicated that most of the scores did not correlate with their corresponding categories. Thus, the way scores are combined into aggression categories may be invalid, because they seem to be combinations of very dissimilar kinds of responses to frustration. Until psychometrically sound and empirically validated ways of combining the 11 scores are determined, it is recommended that the 11 scores themselves be used for clinical and research purposes.

Ultrastructural evidence for the identity of some multinucleate rhizoctonias

The ultrastructure of the pore cap in ten multinucleate rhizoctonias, endophytes of non-orchids and of Microtis (Orchidaceae), was compared with that in isolates of four Sebacina species. The pore cap in all the rhizoctonias was an imperforate, disc-like structure, Slightly smaller in diameter than the flange forming the septal pore canal. The cap was formed by two Bat lamellae continuous with, but more electron-dense than, the membranes of the endoplasmic reticulum. The lamellae enclosed a lumen containing a deposit of electron-dense material. The pore cap in the rhizoctonias was indistinguishable from that in an isolate of Sebacina vermifera Oberwinkler. In contrast, the pore caps in isolates of S. calcea (Pers.: Fr.) Bres., S. umbrina Rogers and S. grisea (Pets.: Fr.) Bres., which were also imperforate and contained a band of electron dense material, were strongly dome-shaped and extended from one side of the flange to the other.

Vinblastine sensitivity of leukaemic lymphoblasts modulated by serum lipid

The high-resolution proton magnetic resonance spectrum of leukaemic lymphoblasts is characteristic of neutral lipid in an isotropic environment. When such lymphoblasts are selected for resistance to the anticancer drug vinblastine, the intensity of this spectrum increases with increasing drug resistance. A reversal of this trend can be achieved by growing cells in delipidated serum, whereby lipid spectrum and drug resistance are diminished. However, both can be restored by subsequent regrowth in normal medium. Thus, although detectable genetic changes accompany the development of vinblastine resistance, the expression of these changes can be modulated by environmental lipid.

Application of a T2-filtered COSY experiment to identify the origin of slowly relaxing species in normal and malignant tissue

The 1H NMR spectrum of whole cells consists of many overlapping resonances which are difficult to resolve into individual components. We have developed a modification of the COSY pulse sequence which filters out resonances on the basis of their T2 relaxation rate. When applied to malignant cells, this technique has helped to identify fucose as the origin of the slowly relaxing species associated with their metastatic capacity. The technique can also be used to obtain T2 relaxation rates for individual resonances in a broad envelope of lines.

Cross-validation of modal responses on the Children's Form of the Rosenzweig Picture-Frustration Study

This study examined whether the modal responses used to determine the Group Conformity Rating on the Children's Form of the Picture-Frustration Study were valid for another sample of comparable size to the standardization sample. Subjects were 245 children in Grades 1 through 6. The modal responses were cross-validated for 19 of the 24 items. Further examinations of the validity of the Group Conformity Rating may be improved if only those items which were cross-validated are used.

Inhibition of metastatic potential by fucosidase: an NMR study identifies a cell surface metastasis marker

NMR spectroscopy is able to detect subtle changes to the surface chemistry of cells. We have previously shown that high-resolution 1H NMR methods can identify tumor cells with the capacity to metastasize, and we now report that the long T2 relaxation value (500-800 ms) observed in metastatic rat mammary adenocarcinoma cells is removed by treatment with fucosidase. Two-dimensional scalar-correlated NMR (COSY) spectra of fucosidase-treated cells show that a cross peak, consistent with scalar coupling between the methyl and methine groups on fucose and usually associated with malignancy and metastatic ability, is absent. Metastases were observed in only two out of ten rats injected subcutaneously with enzyme-treated cells compared to eight out of ten with untreated cells. NMR studies on isolated cellular lipids identified the long T2 relaxation value only in the ganglioside fraction. This fraction accounts for 51% of the total 14C-labelled fucose incorporated into the cells. We propose that fucogangliosides are an indicator of metastatic potential in rats. The observation that a cell surface metastasis marker has an NMR signal with a characteristically long relaxation value has important consequences for the future use of magnetic resonance imaging and spectroscopy in the cancer clinic.

The mycorrhizal relationship of multinucleate rhizoctonias from non-orchids with Microtis (Orchidaceae)

Multinucleate rhizoctonias isolated from the roots of non-orchid plants were used in symbiotic germination tests with seed of 18 orchid species from 10 genera. The rhizoctonias only stimulated germination of Microtis. Investigation of the natural mycosymbionts of adult Microtis failed to yield fungi similar to the original multinucleate rhizoctonias: 27 Microtis plants collected at seven sites in the Sydney region yielded 26 binucleate rhizoctonias tentatively identified as Tulasnella calospora (Boudier) Juel and one very slow growing multinucleate rhizoctonia tentatively identified as Sebacina vermifera Oberwinkler. Fungi closely resembling the original multinucleate rhizoctonias were isolated by baiting the soil with subterranean clover (Trifolium subterraneum L.) plants at three of the seven Microtis sites.

Food service departments in New South Wales--a survey

A survey of all food service departments in NSW hospitals was carried out using a mailed questionnaire. The response rate was 74%. The result reveal that in almost half of the hospitals the head of department had no formal qualifications. Few hospitals used cook-chill or cook-freeze catering systems; the great majority used conventional food production and plated patients meals in a central kitchen location. A significant proportion of hospitals dis not satisfy the Australian Council on Hospital Standards recommendations regarding meal times. In general private hospitals had fewer special diet patients and did not provide food for Meals-on-Wheels. Recommendations are made for the improvement of hospital food service operations.

A comparison of the chemical analyses of cell lipids with their complete proton NMR spectrum

Whole cells are made up of molecules in different environments to which NMR spectroscopy is sensitive. In particular, malignant and transformed cells contain lipids not only in bilayers but in isotropically tumbling domains which give rise to high-resolution spectra. We have recently developed a technique for simultaneously analyzing broadline and high-resolution signals (M. Bloom, K. T. Holmes, C. E. Mountford, and P. G. Williams, J. Magn. Reson., in press) and we report here its application to a range of rat, mouse, and human cell lines. Some selected features of the NMR spectra were compared with the chemical analysis of the whole-cell lipid. We found that in general the proportion of protons in the narrow methylene resonance at 1.3 ppm increased with the neutral lipid content of the cells. This peak was chosen because its T2 relaxation behavior correlates with metastatic potential in a rat model system. This new technique could be applied to other high-resolution components both in healthy and in diseased states.

Reproducibility of Interlaboratory Tritium N.M.R. Results and Influences of Alkyl Substituents on Chemical Shifts of Aromatic Tritons in Alkylbenzenes

Chemical shifts for aromatic tritons have been varying by up to 0.1 ppm when measured in different laboratories. This is attributable to solvent effects. For truly identical solvents this error is shown to reduce to about 0.002 ppm (less than the digitization error). New chemical shift values for aromatic tritons in a series of alkylbenzenes are reported.

Cell surface involvement in cancer metastasis: an NMR study

NMR spectroscopy is one of the few techniques which has the sensitivity to detect subtle changes to the surface chemistry of cells. It has previously been demonstrated that high resolution 1H NMR methods can distinguish tumour cells with the capacity to metastasis and this information appears to arise from a type of proteolipid in or attached to the plasma membrane. Here we report that the 1H NMR signal, which we have used to identify metastatic cells in rat tumours, is significantly reduced in intensity after cultured cells are treated with trypsin/EDTA. The long T2 relaxation value (greater than 350 ms) observed in metastatic cells is absent after enzyme treatment. 2D scalar correlated NMR (COSY) spectra of these treated cells show that a cross peak normally associated with malignancy and metastatic disease is markedly reduced. These findings indicate that the plasma membrane lipid particle which generates the high resolution spectrum is directly affected by trypsin/EDTA. Alterations to the cell surface properties were also demonstrated in vivo since reduced numbers of metastases were observed in animals injected with enzyme-treated cells. The correlation between the absence of a long T2 relaxation value and the diminished numbers of metastases in animals suggests that the plasma membrane particle is involved in the metastatic PROCESS.