Sleep disordered breathing and acute mountain sickness in workers rapidly transported to the South Pole (2835 m)

BACKGROUND

Sleep disordered breathing may be a risk factor for high altitude illness. Past Antarctic sleep studies suggest that rapid transport from sea level (SL) to the Amundsen Scott South Pole Station (SP, 2835 m) increases risk of Acute Mountain Sickness (AMS). We analyzed sleep studies in 38 healthy polar workers to explore the association between sleep disordered breathing and AMS after rapid transport to the South Pole.

METHODS

Subjects completed a baseline questionnaire, performed basic physiology tests, and were evaluated for AMS and medication use using an extended Lake Louise Questionnaire (LLQ) during their first week at the South Pole. Participants were included in this study if they took no medications and underwent polysomnography on their first nights at Sea Level and the South Pole using the Vivometrics LifeShirt(®). Within group changes were assessed with Wilcoxon signed rank tests and between group differences were assessed with Kruskal-Wallis rank sum tests.

RESULTS

Overall, 21/38 subjects met criteria for AMS at some time on or prior to the third morning at the South Pole. Subjective poor sleep quality was reported by both AMS (65%) and no AMS (41%) groups. The Apnea Hypopnea Index (AHI) increased significantly in both the AMS and no AMS groups, but the difference in the increase between the two groups was not statistically significant. Increased AHI was not associated with increased AMS symptoms. Previous altitude illness (p=0.06) and residence at low altitudes (p = 0.02) were risk factors for AMS.

CONCLUSION

AMS was not significantly associated with sleep architecture changes or increased AHI. However, AHI sharply increased at South Pole (19/38 participants) primarily due to central apneas. Those developing AMS were more likely to have experienced previous problems at altitude and reported living at lowland altitudes within the 3 months prior to rapid transport to the South Pole than those without AMS.

Determination of blood volume by pulse CO-oximetry

The objective of this study was to determine whether changes in carboxyhaemoglobin (COHb) saturation following carbon monoxide (CO) rebreathing can be accurately detected by pulse CO-oximetry in order to determine blood volume. Noninvasive measurements of carboxyhaemoglobin saturation (SpCO) were continuously monitored by pulse CO-oximetry before, during and following 2 min of CO rebreathing. Reproducibility and accuracy of noninvasive blood volume measurements were determined in 16 healthy non-smoking individuals (15 males, age: 28 ± 2 years, body mass index: 25.4 ± 0.6 kg m(-2)) through comparison with blood volume measurements calculated from invasive measurements of COHb saturation. The coefficient of variation for noninvasive blood volume measurements performed on separate days was 15.1% which decreases to 9.1% when measurements were performed on the same day. Changes in COHb saturation and SpCO following CO rebreathing were strongly correlated (r = 0.90, p < 0.01), resulting in a significant correlation between invasive and noninvasive blood volume measurements (r = 0.83, p = 0.02). Changes in SpCO following CO rebreathing can be accurately detected by pulse CO-oximetry, which could potentially provide a simplified, convenient and reproducible method to rapidly determine blood volume in healthy individuals.

Breathing strategy to preserve exercising cardiac function in patients with heart failure

The heart and lungs are closely linked as they lie in series, share a common surface area and compete for space within the thoracic cavity. The heart and lungs are exposed to the similar changes in intrathoracic pressure, and reflexes within one organ can influence the other (i.e. vagal influence of lung inflation on heart rate). In patients with heart failure, these cardiopulmonary interactions may be altered due to decreased lung and left ventricular compliance, increased cardiac size, high cardiac filling pressure and altered receptor sensitivity to neural activation. Exercise further affects the cardiopulmonary interactions by stimulating an increase in the depth and frequency of breathing which accentuates the fluctuations in intrathoracic pressure, and by requiring large increases in stroke volume and heart rate in order to respond to the increased metabolic demand. Previous work from our laboratory suggested that patients with heart failure avoid high lung volumes during exercise, often at the expense of unnecessary large positive expiratory intrathoracic pressures resulting in significant wasted effort. Moreover, we also observed that voluntarily increases in lung volume in patients with heart failure induced a mild relative bradycardia, a response not observed in similar aged healthy individuals. Thus, we hypothesized that the rapid shallow low lung volume breathing, in combination with positive expiratory intrathoracic pressure, often adopted by patients with heart failure during exercise is an attempt to preserve, or even enhance, the cardiac response to exercise.

Psychotropic medication use and risk of adverse cardiovascular events in women with suspected coronary artery disease: outcomes from the Women's Ischemia Syndrome Evaluation (WISE) study

OBJECTIVE

This study investigated the relation between psychotropic medication use and adverse cardiovascular (CV) events in women with symptoms of myocardial ischaemia undergoing coronary angiography.

METHOD

Women enrolled in the Women's Ischemia Syndrome Evaluation (WISE) were classified into one of four groups according to their reported antidepressant and anxiolytic medication usage at study intake: (1) no medication (n = 352); (2) anxiolytics only (n = 67); (3) antidepressants only (n = 58); and (4) combined antidepressant and anxiolytics (n = 39). Participants were followed prospectively for the development of adverse CV events (for example, hospitalisations for non-fatal myocardial infarction, stroke, congestive heart failure and unstable angina) or all-cause mortality over a median of 5.9 years.

RESULTS

Use of antidepressant medication was associated with subsequent CV events (HR 2.16, 95% CI 1.21 to 3.93) and death (HR 2.15, 95% CI 1.16 to 3.98) but baseline anxiolytic use alone did not predict subsequent CV events and death. In a final regression model that included demographics, depression and anxiety symptoms, and risk factors for cardiovascular disease, women in the combined medication group (that is, antidepressants and anxiolytics) had higher risk for CV events (HR 3.98, CI 1.74 to 9.10, p = 0.001 and all-cause mortality (HR 4.70, CI 1.7 to 2.97, p = 0.003) compared to those using neither medication. Kaplan-Meier survival curves indicated that there was a significant difference in mortality among the four medication groups (p = 0.001).

CONCLUSIONS

These data suggest that factors related to psychotropic medication such as depression refractory to treatment, or medication use itself, are associated with adverse CV events in women with suspected myocardial ischaemia.

Rapamycin enriches for CD4(+) CD25(+) CD27(+) Foxp3(+) regulatory T cells in ex vivo-expanded CD25-enriched products from healthy donors and patients with multiple sclerosis

BACKGROUND

CD4(+) CD25(bright+) regulatory T cells (Treg) can be expanded to clinical doses using CD3/CD28 Ab-coated beads plus IL-2. However, this method requires high purity of the starting population to prevent overgrowth by non-regulatory T cells. Rapamycin, an agent that inhibits T-cell proliferation but selectively spares Treg, may be a means to expand Treg from less pure CD25-enriched cells.

METHODS

CD25-enriched cells were prepared by a single-step immunomagnetic-selection using anti-CD25 microbeads. The cells were activated with a single addition of anti-CD3/CD28 beads and expanded in ex vivo 15-5% HS and autologous CD4(+) CD25(-) feeder cells,+/-rapamycin (0.01-20 ng/mL). IL-2 was added on day 3. Cells were rested for 2 days in ex vivo 15-5% HS and tested for phenotype, intracellular Foxp3 protein and suppressor activity.

RESULTS

In the absence of rapamycin, CD25-enriched fractions expanded >17 000-fold by 21 days. Although suppressor activity was detected to day 14, it declined significantly by 21 days as non-regulatory cells expanded. The addition of rapamycin inhibited expansion of non-regulatory T cells at doses > or =1 ng/mL while increasing suppressor activity and the percentage of CD4(+) CD25(+) CD27(+) Foxp3(+) cells. Rapamycin did not enrich for Foxp3(+) cells in expanded cultures of CD4(+) CD25(-) cells. Treg were also readily expanded in cultures of CD25-enriched cells obtained from patients with multiple sclerosis in the presence of rapamycin.

DISCUSSION

The addition of 1-20 ng/mL rapamycin to CD25-enriched cultures increased the purity of cells with the phenotype and function of Treg. This approach may alleviate the need for rigorous enrichment of Treg prior to activation and expansion for potential clinical use.

Lentivirus-mediated platelet-derived factor VIII gene therapy in murine haemophilia A

BACKGROUND

Previous studies from our laboratory have demonstrated that lineage-targeted synthesis of factor VIII (FVIII) under the direction of the platelet-specific integrin alphaIIb gene promoter (2bF8) can correct the murine haemophilia A phenotype even in the presence of high titer inhibitory antibodies in a transgenic mouse model.

OBJECTIVE

In this study, we assessed the efficacy of using a genetic therapy approach to correct haemophilia A in FVIII-deficient (FVIII(null)) mice by transplantation of bone marrow (BM) transduced with a lentivirus (LV)-based gene transfer cassette encoding 2bF8.

RESULTS

Functional FVIII activity (FVIII:C) was detected in platelet lysates from treated mice and the levels were similar to 2bF8 heterozygous transgenic mice. Mice transplanted with 2bF8 LV-transduced BM survived tail clipping and we did not detected inhibitory or non-inhibitory FVIII antibodies over the period of this study (11 months). Furthermore, BM transferred from the primary transplant recipients into FVIII(null) secondary recipients demonstrated sustained platelet-FVIII expression leading to correction of the haemophilia A phenotype showing that gene transfer occurred within long-term repopulating haematopoietic stem cells.

CONCLUSIONS

These results demonstrate that ectopic expression of FVIII in platelets by lentivirus-mediated bone marrow transduction/transplantation may be a promising strategy for gene therapy of haemophilia A in humans.

Risks for HIV infection among users and sellers of crack, powder cocaine and heroin in central Harlem: implications for interventions

This article investigates behaviours that may be associated HIV infection among users and sellers of crack, powder cocaine and heroin in central Harlem. Chain referral sampling and other strategies were combined to acquire a sample of 637 (Users = 546; Sellers = 91) who provided urine specimens that were tested for the presence of drugs and HIV. Nearly a quarter (23.9%) of all respondents were HIV positive. Drug injectors were more than 2.5 times more likely to have HIV infections than other respondents (OR = 2.66; 95% CI 1.66-4.26). Those involved in frauds/cons were almost as likely to be HIV positive (OR = 2.58; 95% CI 1.64-4.06). Those with a marital status of being separated, divorced or widowed were twice as likely to be HIV infected (OR 2.16; 95% CI 1.43-3.25). Respondents currently having multiple partner sex (OR = 1.66; 95% CI 1.1-2.51) or who were female (OR = 1.66; 95% CI 1.12-2.45) were more than 1.5 times more likely to be HIV positive. Thus, controlling for lifetime drug injection and current multiple partner sex, other factors, such as participating in frauds/cons, as well as relationship status and being female, were also associated with HIV infection.

The costimulatory molecules CD80, CD86 and OX40L are up-regulated in Aspergillus fumigatus sensitized mice

Aspergillus fumigatus (Af) is a fungus associated with allergic bronchopulmonary aspergillosis (ABPA) and other allergic diseases. Immune responses in these diseases are due to T and B cell responses. T cell activation requires both Af-specific engagement of the T-cell-receptor as well as interaction of antigen independent costimulatory molecules including CD28-CD80/CD86 and OX40-OX40L interactions. Since these molecules and their interactions have been suggested to have a potential involvement in the pathogenesis of ABPA, we have investigated their role in a model of experimental allergic aspergillosis. BALB/c mice were primed and sensitized with Af allergens, with or without exogenous IL-4. Results showed up-regulation of both CD86 and CD80 molecules on lung B cells from Af-sensitized mice (79% CD86+ and 24% CD80+) and Af/rIL-4-treated mice (90% CD86+ and 24% CD80+) compared to normal controls (36% and 17%, respectively). Lung macrophages in Af-sensitized mice treated or not with IL-4 showed enhanced expression of these molecules. OX40L expression was also up-regulated on lung B cells and macrophages from both Af-sensitized and Af/rIL-4 exposed mice as compared to normal controls. All Af-sensitized animals showed peripheral blood eosinophilia, enhanced total serum IgE and allergen-specific IgG1 antibodies and characteristic lung inflammation. The up-regulation of CD80, CD86 and OX40L molecules on lung B cells and macrophages from Af-allergen exposed mice suggests a major role for these molecules in the amplification and persistence of immunological and inflammatory responses in ABPA.

Association between β-adrenergic receptor polymorphisms and their G-protein-coupled receptors with body mass index and obesity in women: a report from the NHLBI-sponsored WISE study

OBJECTIVES

The beta-adrenergic receptor (betaAR) genes are candidate genes for obesity because of their roles in energy homeostasis and promotion of lipolysis in human adipose tissue. Objective is to determine the association between obesity and polymorphisms in genes of the beta(1)AR (ADRB1), beta(2)AR (ADRB2), beta(3)AR (ADRB3), Gs protein alpha (GNAS1), to which all three beta-receptors couple and the G protein beta3 subunit (GNB3), to which beta(3)ARs couple.

DESIGN

A case-control genetic association study.

SUBJECTS

A total of 643 black or white women enrolled in Women's Ischemia Syndrome Evaluation (WISE) study.

MEASUREMENTS

Genotypes were determined by PCR with single primer extension. Associations between genotype and body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, and obesity were made.

RESULTS

Polymorphisms in the three betaAR genes, GNAS1, and GNB3 were not associated with BMI, WHR, waist circumference, or obesity. Linear and logistic regression analyses found no contribution of either genotype or haplotype with anthropometric measurements or obesity.

CONCLUSIONS

Our study suggests that among American women with suspected coronary heart disease, polymorphisms in the betaARs and their G-protein-coupled receptors do not contribute to increased BMI, WHR, waist circumference, or obesity. Given that 50% of all women die from coronary heart disease, and a higher percentage have heart disease during their lifetime, our results are likely generalizable to many American women.

Induction of megakaryocytes to synthesize and store a releasable pool of human factor VIII

von Willebrand factor (VWF) is a complex plasma glycoprotein that modulates platelet adhesion at the site of a vascular injury, and it also serves as a carrier protein for factor (F)VIII. As megakaryocytes are the only hematopoietic lineage to naturally synthesize and store VWF within alpha-granules, this study was performed to determine if expression of a FVIII transgene in megakaryocytes could lead to trafficking and storage of FVIII with VWF in platelet alpha-granules. Isolex selected CD34+ cells from human G-CSF mobilized peripheral blood cells (PBC) and murine bone marrow were transduced with a retrovirus encoding the B-domain deleted form of human FVIII (BDD-FVIII). Cells were then induced with cytokines to form a population of multiple lineages including megakaryocytes. Chromogenic analysis of culture supernatant from FVIII-transduced human cells demonstrated synthesis of functional FVIII. Treatment of cells with agonists of platelet activation (ADP, epinephrine, and thrombin receptor-activating peptide) resulted in the release of VWF antigen and active FVIII into the supernatant from transduced cells. Immunofluorescence analysis of cultured human and murine megakaryocytes revealed a punctate pattern of staining for FVIII that was consistent with staining for VWF. Electron microscopy of transduced megakaryocytes using immunogold-conjugated antibodies colocalized FVIII and VWF within the alpha-granules. FVIII retained its association with VWF in human platelets isolated from the peripheral blood of NOD/SCID mice at 2-6 weeks post-transplant of transduced human PBC. These results suggest feasibility for the development of a locally inducible secretory pool of FVIII in platelets of patients with hemophilia A.

Attention Deficit Hyperactivity Disorder: scaling and standard setting using Rasch measurement

This paper explores the dimensionality of responses to the Adult Behavior Checklist Revised, a screening assessment for Attention Deficit Hyperactivity Disorder (ADHD) in college students, and demonstrates a standard setting process for diagnostic rating scales. Responses from 317 undergraduate college students were used to investigate dimensionality; 8 judges were used for the standard setting procedure. A series of Rasch rating scale analyses support the interpretation of Inattention and Impulsivity/Hyperactivity variables. Principal component analyses of residuals identified the existence of secondary variables that may have clinical implications for the evaluation and treatment of ADHD. For the standard setting process, judges generally displayed less variability than expected by the model. Several judges were in disagreement as to the level of symptomatology needed to indicate potential ADHD. The derived standard for Inattention was found to be more stringent than a previously suggested standard while the derived standard for Hyperactive/Impulsive more lenient. Prevalence rates found a diagnosis of Hyperactive/Impulsive to be more common than a diagnosis of Inattention. Efficient screening assessments for ADHD in college students are needed in order to determine who may qualify for further evaluation and special services. The standard setting process attempts to identify judge disagreement regarding the level of symptomatology (the standard) needed to qualify for additional evaluation and identify judge response strings not consistent with the item difficulties. Recommendations suggesting additional work on the screening assessment and standard setting process are outlined.

Donor natural killer (NK1.1+) cells do not play a role in the suppression of GVHD or in the mediation of GVL reactions after DLI

Donor regulatory T cells (CD3+ alphabetaT-cell receptor [TCR]+) derived from the repopulating host thymus have been shown to be primarily responsible for suppression of GVHD following DLI therapy in murine BMT models. However, natural killer (NK) T cells also have regulatory properties, and a role for NK T cells in suppression of GVH reactivity has not been completely excluded. NK cells may also contribute to the graft-versus-leukemia (GVL) effect associated with DLI therapy. In this study, we used a murine BMT model (C57BL/6 into AKR) to study whether depletion of donor NK cells had any impact on the suppression of GVH reactivity after DLI or on the DLI-induced GVL effect against acute T-cell leukemia. Depletion of donor NK cells was accomplished in vivo by giving DLI-treated bone marrow chimeras multiple injections of anti-NK1.1 monoclonal antibody (MoAb). The chimeras treated with anti-NK1.1 MoAb had significantly fewer splenic NK1.1 cells than nontreated chimeras, and splenocytes from anti-NK1.1-treated mice were deficient in the ability to generate lymphokine-activated lytic activity. Results presented here showed that NK-cell depletion had no effect on the suppression of GVH reactivity after DLI. When DLI-treated chimeras were challenged with an acute T-cell leukemia, NK-cell depletion had no discernible effect on GVL reactivity. These preclinical data suggest that donor NK cells do not have a significant role in the suppression of GVHD after DLI or in the mediation of GVL reactivity induced by DLI.

Pulmonary function in patients with reduced left ventricular function: influence of smoking and cardiac surgery

STUDY OBJECTIVE

The impact of stable, chronic heart failure on baseline pulmonary function remains controversial. Confounding influences include previous coronary artery bypass or valve surgery (CABG), history of obesity, stability of disease, and smoking history.

DESIGN

To control for some of the variables affecting pulmonary function in patients with chronic heart failure, we analyzed data in four patient groups, all with left ventricular (LV) dysfunction (LV ejection fraction [LVEF] < or =35%): (1) chronic heart failure, nonsmokers, no CABG (n = 78); (2) chronic heart failure, nonsmokers, CABG (n = 46); (3) chronic heart failure, smokers, no CABG (n = 40); and (4) chronic heart failure, smokers, CABG (n = 48). Comparisons were made with age- and gender-matched patients with a history of coronary disease but no LV dysfunction or smoking history (control subjects, n = 112) and to age-predicted norms.

RESULTS

Relative to control subjects and percent-predicted values, all groups with chronic heart failure had reduced lung volumes (total lung capacity [TLC] and vital capacity [VC]) and expiratory flows (p < 0.05). CABG had no influence on lung volumes and expiratory flows in smokers, but resulted in a tendency toward a reduced TLC and VC in nonsmokers. Smokers with chronic heart failure had reduced expiratory flows compared to nonsmokers (p < 0.05), indicating an additive effect of smoking. Diffusion capacity of the lung for carbon monoxide (DLCO) was reduced in smokers and in subjects who underwent CABG, but not in patients with chronic heart failure alone. There was no relationship between LV size and pulmonary function in this population, although LV function (cardiac index and stroke volume) was weakly associated with lung volumes and DLCO.

CONCLUSIONS

We conclude that patients with chronic heart failure have primarily restrictive lung changes with smoking causing a further reduction in expiratory flows.

Electrofusion of a weakly immunogenic neuroblastoma with dendritic cells produces a tumor vaccine

The absence of surface costimulatory molecules explains in part the lack of an effective anti-tumor immune response in tumor-bearing animals, even though unique tumor antigens may be presented by class I MHC. We determined that the immunogenicity of a murine neuroblastoma, Neuro-2a, which lacks surface costimulatory molecules, could be increased by electrically induced fusion with dendritic cells. Electrofusion induced a higher level of cell fusion than polyethylene glycol, and tumor/dendritic cell heterokaryons expressed high levels of costimulatory molecules. While Neuro-2a was unable to induce the proliferation of syngeneic or allogeneic T cells in vitro, fused cells were able to induce T cell responses both in vitro and in vivo. When fused dendritic tumor cells were used as a cancer vaccine, immunized mice were significantly protected from challenge with Neuro-2a. We propose that electrofusion with patient-derived tumor and dendritic cells may provide a rapid means to produce patient-specific tumor vaccines.

Supporting the habit: income generation activities of frequent crack users compared with frequent users of other hard drugs

US Federal sentencing guidelines punish possession of crack cocaine very differently from powder cocaine, based partially upon the assumption that crack users engage more frequently in criminal behavior to pay for their habit. This article analyzed frequent users (those who have used at least 15 of the last 30 days) of crack with subgroups of less frequent hard drug users in terms of various income generation activities reported during the past 30 days. The sample consists of 602 African-Americans who were current (in past 30 days) users or sellers of cocaine powder, crack, and heroin. They were carefully recruited from randomly selected blocks in the Central Harlem area of New York City and interviewed extensively in 1998-1999. Their IGAs were classified into six categories. Compared with not-frequent (less than 15 days) hard drug users, frequent crack and multiple hard drug users were equally likely to be involved in drug distribution activities, but were significantly less likely to have full-time jobs, part-time jobs, aid to families with dependent children or welfare support. They had much higher odds ratios for non-drug related illegal (theft mainly) income generation activities and sex work among women. Often, gender and birth cohort variables had higher odds ratios with specific income generation activities than the frequent use of the primary drug(s). This evidence suggests that very frequent crack users have been stigmatized by, are largely excluded from, and perform very marginal economic roles in the legal economic system (jobs and welfare), the illegal economic system, and even in the hard drug distribution system.

Is the U.S. experiencing an incipient epidemic of hallucinogen use?

NHSDA and MTF survey data indicate "epidemic"-like growth in hallucinogen use from 1992-1996 and associated increases in cocaine, crack, heroin and amphetamine use. These trends might have resulted from a proliferation of raves and dance clubs in the U.S. as occurred in Europe and elsewhere, although in contrast to evidence regarding European experiences the American epidemic involves primarily teens as opposed to persons in their twenties and involves primarily use of LSD as opposed to MDMA. This analysis highlights the need for further research into the context, significance, and consequences of these recently popular American drug use practices.

Diagnostic, prognostic, and cost assessment of coronary artery disease in women

Women with obstructive coronary disease appear to be more challenging diagnostically and suffer a more adverse prognosis than men. More than one half of women with symptoms of ischemic heart disease have no obstructive coronary artery disease at coronary angiography, yet these women frequently have persistent symptom-related disability and consume large amounts of healthcare resources. Prior evidence has been limited regarding effective diagnostic strategies for the assessment of symptomatic women. The current report synthesizes existing evidence on diagnostic testing in women, including research from the ongoing National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE) study. In addition to recent published evidence (drawn from much larger cohorts of women) that stress echocardiography and nuclear imaging are similar in their ability to risk-stratify women, the WISE study is exploring new pathophysiological mechanisms of microvascular dysfunction in women. An unfolding body of evidence suggests that as tests become more diagnostically and prognostically accurate, the process will become more cost efficient. The results from a growing number of large observational series and National Institutes of Health-sponsored studies are expected to be the foundation for cost-effective diagnostic and prognostic strategies for the approximately 5 million women who undergo evaluation for coronary disease annually.

6-Substituted-4-(3-bromophenylamino)quinazolines as putative irreversible inhibitors of the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases with enhanced antitumor activity

A series of new 6-substituted-4-(3-bromophenylamino)quinazoline derivatives that may function as irreversible inhibitors of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor (HER-2) tyrosine kinases have been prepared. These inhibitors have, at the C-6 position, butynamide, crotonamide, and methacrylamide Michael acceptors bearing water-solublilizing substituents. These compounds were prepared by acylation of 6-amino-4-(3-bromophenylamino)quinazoline with unsaturated acid chlorides or mixed anhydrides. We show that attaching a basic functional group onto the Michael acceptor results in greater reactivity, due to intramolecular catalysis of the Michael addition and/or an inductive effect of the protonated basic group. This, along with improved water solubility, results in compounds with enhanced biological properties. We present molecular modeling and experimental evidence that these inhibitors interact covalently with the target enzymes. One compound, 16a, was shown to have excellent oral activity in a human epidermoid carcinoma (A431) xenograft model in nude mice.

Cloning and expression of Aspergillus fumigatus allergen Asp f 16 mediating both humoral and cell-mediated immunity in allergic bronchopulmonary aspergillosis (ABPA)

BACKGROUND

Aspergillus fumigatus, a ubiquitous fungus, is responsible for a number of lung disorders in atopic and non-atopic individuals. Standardized, pure, and relevant allergens are desirable for reliable immunodiagnosis of the disease and to understand the structural and functional properties of these allergens and the role they play in causing ABPA.

OBJECTIVE

Molecular cloning and characterization of a relevant allergen from A. fumigatus cDNA library.

MATERIALS AND METHODS

A cDNA library was constructed from 96 h old mycelium of A. fumigatus using lambda ZAP expression vector. A novel gene encoding an A. fumigatus allergen was identified by screening the library with sera from ABPA patients. The gene was cloned and the allergen over-expressed in Escherichia coli. This recombinant allergen, Asp f 16, was evaluated in ELISA and Western blots using sera from patients and normal subjects and peripheral blood mononuclear cells (PBMC) for antigen-induced stimulation.

RESULTS

Seventy percent of the patients with ABPA demonstrated high levels of serum IgE antibodies to Asp f 16, a 43-kDa protein, whereas patients with allergic asthma, Aspergillus skin test-positive asthmatics without clinical evidence of ABPA, and normal controls failed to show Asp f 16-specific IgE binding by ELISA. The deduced amino acid sequences of Asp f 16 showed extensive sequence homology to 30.6-kDa Asp f 9 at the N-terminal region of the protein. PBMC from the majority of patients with ABPA exhibited significant proliferation with the recombinant Asp f 16 allergen.

CONCLUSION

Specific humoral and cell-mediated immune responses of Af-sensitized patients against Asp f 16 suggest its usefulness in the immunodiagnosis of hypersensitivity diseases due to Af and understanding the pathophysiology of ABPA.

Variation in youthful risks of progression from alcohol and tobacco to marijuana and to hard drugs across generations

OBJECTIVES

Much research has documented that youthful substance use typically follows a sequence starting with use of alcohol or tobacco or both and potentially proceeding to marijuana and then hard drug use. This study explicitly examined the probabilities of progression through each stage and their covariates.

METHODS

A secondary analysis of data from the National Household Survey on Drug Abuse (1979-1997) was conducted with particular sensitivity to the nature of substance use progression, sampling procedures, and reliability of self-report data.

RESULTS

Progression to marijuana and hard drug use was uncommon among persons born before World War II. The stages phenomenon essentially emerged with the baby boom and rose to a peak among persons born around 1960. Subsequently, progression risks at each stage declined. Progression risks were also higher among younger initiators of alcohol, tobacco, or marijuana use.

CONCLUSIONS

The recent increase in youthful marijuana use has been offset by lower rates of progression to hard drug use among youths born in the 1970s. Dire predictions of future hard drug abuse by youths who came of age in the 1990s may be greatly overstated.

Hsp90 chaperone activity requires the full-length protein and interaction among its multiple domains

Hsp90 is an abundant and ubiquitous protein involved in a diverse array of cellular processes. Mechanistically we understand little of the apparently complex interactions of this molecular chaperone. Recently, progress has been made in assigning some of the known functions of hsp90, such as nucleotide binding and peptide binding, to particular domains within the protein. We used fragments of hsp90 and chimeric proteins containing functional domains from hsp90 or its mitochondrial homolog, TRAP1, to study the requirements for this protein in the folding of firefly luciferase as well as in the prevention of citrate synthase aggregation. In agreement with others who have found peptide binding and limited chaperone ability in fragments of hsp90, we see that multiple fragments from hsp90 can prevent the aggregation of thermally denatured citrate synthase, a measure of passive chaperoning activity. However, in contrast to these results, the luciferase folding assay was found to be much more demanding. Here, folding is mediated by hsp70 and hsp40, requires ATP, and thus is a measure of active chaperoning. Hsp90 and the co-chaperone, Hop, enhance this process. This hsp90 activity was only observed using full-length hsp90 indicating that the cooperation of multiple functional domains is essential for active, chaperone-mediated folding.

4-Anilino-6,7-dialkoxyquinoline-3-carbonitrile inhibitors of epidermal growth factor receptor kinase and their bioisosteric relationship to the 4-anilino-6,7-dialkoxyquinazoline inhibitors

The synthesis and SAR of a series of 4-anilino-6, 7-dialkoxyquinoline-3-carbonitrile inhibitors of epidermal growth factor receptor (EGF-R) kinase are described. Condensation of 3, 4-dialkoxyanilines with ethyl (ethoxymethylene)cyanoacetate followed by thermal cyclization gave, regiospecifically, 6,7-dialkoxy-4-oxo-1, 4-dihydroquinoline-3-carbonitriles. Chlorination (POCl(3)) followed by the reaction with substituted anilines furnished the 4-anilino-6, 7-dialkoxyquinoline-3-carbonitrile inhibitors of EGF-R kinase. An alternate synthesis of these compounds starts with a methyl 3, 4-dialkoxybenzoate. Nitration followed by reduction (Fe, NH(4)Cl, MeOH-H(2)O) gave a methyl 2-amino-4,5-dialkoxybenzoate. Amidine formation using DMF-acetal followed by cyclization using LiCH(2)CN furnished a 6,7-dialkoxy-4-oxo-1,4-dihydroquinoline-3-carbonitrile, which was transformed as before. Compounds containing acid, ester, amide, carbinol, and aldehyde groups at the 3-position of the quinoline ring were also prepared for comparison, as were several 1-anilino-6,7-dimethoxyisoquinoline-4-carbonitriles. The compounds were evaluated for their ability to inhibit the autophosphorylation of the catalytic domain of EGF-R. The SAR of these inhibitors with respect to the nature of the 6,7-alkoxy groups, the aniline substituents, and the substituent at the 3-position was studied. The compounds were further evaluated for their ability to inhibit the growth of cell lines that overexpress EGF-R or HER-2. It was found that 4-anilinoquinoline-3-carbonitriles are effective inhibitors of EGF-R kinase with activity comparable to the 4-anilinoquinazoline-based inhibitors. A new homology model of EGF-R kinase was constructed based on the X-ray structures of Hck and FGF receptor-1 kinase. The model suggests that with the quinazoline-based inhibitors, the N3 atom is hydrogen-bonded to a water molecule which, in turn, interacts with Thr 830. It is proposed that the quinoline-3-carbonitriles bind in a similar manner where the water molecule is displaced by the cyano group which interacts with the same Thr residue.

Cardiac output during exercise by the open circuit acetylene washin method: comparison with direct Fick

An open-circuit (OpCirc) acetylene uptake cardiac output (QT) method was modified for use during exercise. Two computational techniques were used. OpCirc1 was based on the integrated uptake vs. end-tidal change in acetylene, and OpCirc2 was based on an iterative finite difference modeling method. Six subjects [28-44 yr, peak oxygen consumption (VO(2)) = 120% predicted] performed cycle ergometry exercise to compare QT using OpCirc and direct Fick methods. An incremental protocol was repeated twice, separated by a 10-min rest, and subsequently subjects exercised at 85-90% of their peak work rate. Coefficient of variation of the OpCirc methods and Fick were highest at rest (OpCirc1, 7%, OpCirc2, 12%, Fick, 10%) but were lower at moderate to high exercise intensities (OpCirc1, 3%, OpCirc2, 3%, Fick, 5%). OpCirc1 and OpCirc2 QT correlated highly with Fick QT (R(2) = 0.90 and 0.89, respectively). There were minimal differences between OpCirc1 and OpCirc2 compared with Fick up to moderate-intensity exercise (<70% peak VO(2)); however, both techniques tended to underestimate Fick at >70% peak VO(2). These differences became significant for OpCirc1 only. Part of the differences between Fick and OpCirc methods at the higher exercise intensities are likely related to inhomogeneities in ventilation and perfusion matching (R(2) = 0.36 for Fick - OpCirc1 vs. alveolar-to-arterial oxygen tension difference). In conclusion, both OpCirc methods provided reproducible, reliable measurements of QT during mild to moderate exercise. However, only OpCirc2 appeared to approximate Fick QT at the higher work intensities.

Chiral capillary electrophoretic analysis of the enantiomeric purity of a pharmaceutical compound using sulfated beta-cyclodextrin

A practical chiral capillary electrophoresis method using randomly sulfated beta-cyclodextrin was developed for the quantitative determination of the chiral purity of a pharmaceutical compound. A systematic method development approach was conducted by modifying selected parameters such as the concentration of the chiral selectors, buffer pH, organic modifiers, buffer concentrations and type, temperature and applied voltage. The results of the investigation permitted an improved understanding of the separation mechanism. Two facile strategies for the reversal of the enantiomer elution order are also described. The optimized method was validated in terms of variability of the chiral selector, linearity, sensitivity, accuracy, recovery, ruggedness, and precision.

Ventilatory constraints during exercise in patients with chronic heart failure

We examined the degree of ventilatory constraint in patients with a history of chronic heart failure (CHF; n = 11; mean +/- SE age, 62 +/- 4 years; cardiac index [CI], 2.0 +/- 0.1; and ejection fraction [EF], 24 +/- 2%) and in control subjects (CTLS; n = 8; age, 61 +/- 5 years; CI, 2.6 +/- 0.3) by plotting the tidal flow-volume responses to graded exercise in relationship to the maximal flow-volume envelope (MFVL). Inspiratory capacity (IC) maneuvers were performed to follow changes in end-expiratory lung volume (EELV) during exercise, and the degree of expiratory flow limitation was assessed as the percent of the tidal volume (VT) that met or exceeded the expiratory boundary of the MFVL. CHF patients had significantly (p < 0.05) reduced baseline pulmonary function (FVC, 76 +/- 4%; FEV(1), 78 +/- 4% predicted) relative to CTLS (FVC, 99 +/- 4%; FEV(1), 102 +/- 4% predicted). At peak exercise, oxygen consumption (VO(2)) and minute ventilation (V(E)) were lower in CHF patients than in CTLS (VO(2), 17 +/- 2 vs 32 +/- 2 mL/kg/min; VE, 56 +/- 4 vs 82 +/- 6 L/min, respectively), whereas VE/carbon dioxide output was higher (42 +/- 4 vs 29 +/- 5). In CTLS, EELV initially decreased with light exercise, but increased as VE and expiratory flow limitation increased. In contrast, the EELV in patients with CHF remained near residual volume (RV) throughout exercise, despite increasing flow limitation. At peak exercise, IC averaged 91 +/- 3% and 79 +/- 4% (p < 0.05) of the FVC in CHF patients and CTLS, respectively, and flow limitation was present over > 45% of the VT in CHF patients vs < 25% in CTLS (despite the higher VE in CTLS). The least fit and most symptomatic CHF patients demonstrated the lowest EELV, the greatest degree of flow limitation, and a limited response to increased inspired carbon dioxide during exercise, all consistent with VE constraint. We conclude that patients with CHF commonly breathe near RV during exertion and experience expiratory flow limitation. This results in VE constraint and may contribute to exertional intolerance.

Broadband control of plate radiation using a piezoelectric, double-amplifier active-skin and structural acoustic sensing

The potential of a piezoelectric, double-amplifier active-skin with structural acoustic sensing (SAS) is demonstrated for the reduction of broadband acoustic radiation from a clamped, aluminum plate. The active-skin is a continuous covering of the vibrating portions of the plate with active, independently controllable piezoelectric, double-amplifier elements and is designed to affect control by altering the continuous structural radiation impedance rather than structural vibration. In simulation, acoustic models are sought for the primary and secondary sources that incorporate finite element methods. Simulation indicates that a total radiated power attenuation in excess of 10 dB may be achieved between 250 and 750 Hz with microphone error sensing, while under SAS the radiated power is reduced by nearly 8 dB in the same frequency range. In experiment, the adaptive feed forward filtered-x LMS (least mean square) algorithm, implemented on a Texas Instruments C40 DSP, was used in conjunction with the 6I6O control system. With microphone error sensing, 11.8-dB attenuation was achieved in the overall radiated power between 175 and 600 Hz, while inclusion of SAS resulted in a 7.3-dB overall power reduction in this frequency band.

Chromatographic separation of 3,4-difluorophenylacetic acid and its positional isomers using five different techniques

The separation of five positional isomers from 3,4-difluorophenylacetic acid was investigated using normal- and reversed-phase high-performance liquid chromatography, capillary zone electrophoresis, gas chromatography and supercritical fluid chromatography. Operating parameters of each technique, such as temperature, type of stationary phase, mobile phase pH, ionic strength, organic modifiers and additives were varied in order to elucidate the separation mechanisms. Based on the advantages and disadvantages of each methodology, a simple and practical RPLC method was selected. The method was validated in terms of linearity, limit of detection, accuracy, recovery, ruggedness and precision.

Role of immunoregulatory donor T cells in suppression of graft-versus-host disease following donor leukocyte infusion therapy

In murine models of allogeneic bone marrow transplantation (BMT), MHC-mismatched recipients given a delayed infusion of donor leukocytes (DLI) at 21 days posttransplant develop significant GVHD whereas MHC-matched recipients do not. The current study was initially designed to test the hypothesis that small numbers of T cells in the MHC-mismatched donor bone marrow (BM) graft exacerbated graft-vs-host disease (GVHD) when DLI was administered at 21 days after BMT. Ex vivo depletion of Thy1+ cells from the donor BM had no impact on the severity of GVHD after DLI. However, depletion of donor T cells in vivo with a Thy1 allele-specific mAb given after BMT resulted in significantly more severe GVHD after DLI. Similar results were obtained in a MHC-matched model of allogeneic BMT, indicating that this was a general phenomenon and not model dependent. These results indicated that a population of donor-derived Thy1+ cells suppressed graft-vs-host reactivity after DLI. Results of experiments with thymectomized recipients demonstrated that an intact thymus was required for generation of the immunoregulatory donor cells. Experiments using TCR beta-chain knockout mice as BM donors indicated that the immunosuppressive Thy1+ cells coexpressed alphabetaTCR heterodimers. Similar experiments with CD4 and CD8 knockout donor BM suggested that the immunoregulatory Thy1+alphabetaTCR+ cells consisted of two subpopulations: a CD4+CD8- subpopulation and a CD4-CD8- subpopulation. Together, these results show that thymus-derived, Thy1+alphabetaTCR+ donor cells generated early after allogeneic BMT suppress the graft-vs-host reactivity of T cells given as DLI. These cells may mediate dominant peripheral tolerance after allogeneic BMT.

Purified and recombinant latex proteins stimulate peripheral blood lymphocytes of latex allergic patients

BACKGROUND

Natural rubber latex proteins have been implicated in severe allergy in individuals exposed to latex products, particularly health care workers. Until recently, only crude antigens were available to study the immune response in these patients. In recent years a number of relevant allergens have been purified, but few have been used in lymphocyte studies. Hence, to better understand the immunological mechanisms involved in latex allergy, we investigated the response of peripheral blood mononuclear cells (PBMCs) to various purified natural rubber latex allergens.

METHODS

Using conventional protein purification methods and gene cloning, we have obtained 6 natural rubber latex proteins. We studied allergen-specific IgE levels and PBMC responses to these allergens along with 3 crude latex antigen preparations.

RESULTS

Of the 28 latex-allergic health care workers studied, 16 reacted to one or more of the allergens studied, but PBMCs from controls failed to respond to these antigens. Serum IgE to the antigens was detected in 11-90% of the patients.

CONCLUSION

Fifty-seven percent of the latex-allergic patients demonstrated PBMC responses to at least one of the latex allergens tested, but there was no direct correlation between serum IgE levels and PBMC responses. However, since none of the control subjects showed any PBMC stimulation, this may prove useful in determining sensitization to latex. Among the allergens studied, the predominant mononuclear cell responses were directed against Hev b 2, while serum IgE against rHev b 6 was demonstrable in the greatest number of patients. The crude latex allergens were toxic to PBMCs and hence, the purified allergens may be of greater value in demonstrating sensitization of patients to latex allergens.

Photochemical treatment with S-59 psoralen and ultraviolet A light to control the fate of naive or primed T lymphocytes in vivo after allogeneic bone marrow transplantation

Donor leukocyte infusions after allogeneic bone marrow transplantation can provide a curative graft-vs-leukemia (GVL) effect, but there is a significant risk of graft-vs-host (GVH) disease. A simple and effective method for controlling the fate of naive or primed T-lymphocytes in vivo without eliminating their beneficial properties is needed. In this report, photochemical treatment (PCT) ex vivo with a synthetic psoralen (S-59) and UVA light was evaluated as a pharmacological approach to limiting the proliferation and GVH potential of naive and primed donor T cells in vivo. S-59 rapidly intercalates into and cross-links DNA on UVA illumination. The effects of PCT on T cells were found to be both S-59 and UVA dose dependent. With selected PCT regimens, treated T cells still expressed activation markers (CD25 and CD69) and secreted IL-2 on activation, but they showed limited proliferative capacity in vitro and in vivo. Clonal expansion of CTL in MLR was reduced after PCT, but short term lytic activity of primed CTL was not affected. In a murine model of MHC-mismatched bone marrow transplantation, the addition of PCT-treated T cells to T-depleted bone marrow facilitated donor engraftment and complete chimerism without causing acute or chronic graft-vs-host disease. Allospecific GVL reactivity was reduced but not eliminated after PCT treatment. In an MHC-matched model using host-presensitized donor T cells, PCT significantly reduced GVH-associated mortality without eliminating GVL reactivity. Thus, PCT ex vivo offers a simple, rapid, and inexpensive method by which to control the fate of naive and primed T cells in vivo.

Advances in pulmonary laboratory testing

This review examines emerging technologies that are of potential use in the routine clinical pulmonary laboratory. These technologies include the following: the measurement of exercise tidal flow-volume (FV) loops plotted within the maximal FV envelope for assessment of ventilatory constraint during exercise; the use of negative expiratory pressures to asses expiratory flow limitation in various populations and under various conditions; the potential use of expired nitric oxide for assessing airway inflammation; and the use of forced oscillation for assessment of airway resistance. These methodologies have been used extensively in the research setting and are gaining increasing popularity and clinical application due to the availability of commercially available, simplified, and automated systems. An overview of each technique, its potential advantages and limitations will be discussed, along with suggestions for further investigation that is considered necessary prior to extensive clinical use.

Cohort changes in illegal drug use among arrestees in Manhattan: from the Heroin Injection Generation to the Blunts Generation

This paper identifies three inner-city cohorts differing by birth year and preferred drugs that routinely passed through Manhattan's criminal justice system from 1987 through 1997: The Heroin Injection Generation born 1945-54, the Cocaine/Crack Generation born 1955-69, and the Blunts (marijuana plus tobacco) Generation born since 1970. The future prospects for the Blunts Generation may be modestly enhanced by their continued avoidance of cocaine, crack, and heroin--despite the fact that many of them are being reared in severely distressed households and are developing few skills for legal jobs.

Emerging concepts in the evaluation of ventilatory limitation during exercise: the exercise tidal flow-volume loop

Traditionally, ventilatory limitation (constraint) during exercise has been determined by measuring the ventilatory reserve or how close the minute ventilation (VE) achieved during exercise (i.e., ventilatory demand) approaches the maximal voluntary ventilation (MVV) or some estimate of the MVV (i.e., ventilatory capacity). More recently, it has become clear that rarely is the MVV breathing pattern adopted during exercise and that the VE/MVV relationship tells little about the specific reason(s) for ventilatory constraint. Although it is not a new concept, by measuring the tidal exercise flow-volume (FV) loops (extFVLs) obtained during exercise and plotting them according to a measured end-expiratory lung volume (EELV) within the maximal FV envelope (MFVL), more specific information is provided on the sources (and degree) of ventilatory constraint. This includes the extent of expiratory flow limitation, inspiratory flow reserve, alterations in the regulation of EELV (dynamic hyperinflation), end-inspiratory lung volume relative to total lung capacity (or tidal volume/inspiratory capacity), and a proposed estimate of ventilatory capacity based on the shape of the MFVL and the breathing pattern adopted during exercise. By assessing these types of changes, the degree of ventilatory constraint can be quantified and a more thorough interpretation of the cardiopulmonary exercise response is possible. This review will focus on the potential role of plotting the extFVL within the MFVL for determination of ventilatory constraint during exercise in the clinical setting. Important physiologic concepts, measurements, and limitations obtained from this type of analysis will be defined and discussed.

Graft-vs.-host and graft-vs.-leukemia reactions after delayed infusions of donor T-subsets

Infusions of donor leukocytes have been given to allogeneic bone marrow recipients after transplant to treat leukemia relapse. Treatment with these delayed infusions of donor cells has been called delayed or donor leukocyte infusion (DLI). While graft-vs.-host disease (GVHD) has typically been less severe than expected after DLI, it still remains a significant risk factor. Recently, we used a full major histocompatibility complex (MHC)-mismatched model (C57BL/6 into AKR) to determine how increased immunogenetic disparity affects GVH and graft-vs.-leukemia (GVL) reactions after DLI. In contrast to an MHC-matched model (B10.BR into AKR), GVHD was still observed when MHC-mismatched donor T cells were infused 3 weeks posttransplant. Limiting dilution analysis was used to determine the frequency of alloreactive cytotoxic T lymphocytes (CTL) and interleukin (IL)-2-secreting T helper cells in the spleens of MHC-mismatched recipients 7 days after DLI treatment. GVHD correlated with elevated frequencies of alloreactive T-helper cells. One strategy for reducing the severity of GVHD after DLI is the selective administration of CD4 or CD8 T-subsets. Delayed infusion of purified T-subsets 3 weeks posttransplant resulted in significantly less GVHD than infusion of a mixture of the two subsets. No GVH-associated mortality was observed after DLI with purified donor CD4+ T cells. In GVL studies, MHC-mismatched CD8+ T cells were the most potent antitumor effectors against an acute T cell leukemia. The GVL effect of MHC-mismatched T-subsets was compared with that of MHC-matched subsets. When naive MHC-matched cells were given as DLI, depletion of either T-subset eliminated the GVL effect. CD8+ T cells from MHC-matched donors primed against host alloantigens, however, mediated a CD4 (T-helper)-independent GVL reaction. Together, these results suggest that administration of T-subsets can significantly reduce GVHD after DLI without loss of the beneficial GVL effect.

Non-physician supervision of cardiopulmonary exercise testing in chronic heart failure: safety and results of a preliminary investigation

PURPOSE

In the current era of efficient use of personnel and cost containment, the use of non-physicians in selected roles previously occupied exclusively by physicians has become increasingly prevalent. Traditionally, physicians have directly supervised graded exercise testing of patients with chronic heart failure. The purpose of this prospective pilot investigation was to determine the safety and results of non-physician supervised exercise testing of these high-risk patients.

METHODS

Two hundred eighty-nine consecutive outpatients (211 men, 78 women) with left ventricular ejection fractions of < or = 35% were referred for cardiopulmonary exercise testing. Symptom-limited treadmill graded exercise tests were supervised by paramedical personnel with a physician immediately available, but not present in the lab.

RESULTS

Nonsustained ventricular tachycardia was present during exercise in approximately 20% of patients. Test-limiting hypotension was documented in 5% of subjects. Only one serious event occurred during the 289 exercise tests, an episode of ventricular fibrillation with a successful resuscitation outcome. Peak exercise respiratory exchange ratio averaged 1.10 +/- 0.14, consistent with a near-maximal patient effort. Peak oxygen uptake was 18 +/- 5 ml/kg/min.

CONCLUSIONS

Supervision of cardiopulmonary graded exercise testing in properly screened patients with severe systolic left ventricular dysfunction by experienced non-physicians appears to be reasonably safe and the results are suitable for clinical decision making. Such a practice is an attractive cost-containment strategy and deserves further investigation.

Lung growth response after tracheal occlusion in fetal rabbits is gestational age-dependent

In utero tracheal occlusion (TO) is a potent stimulus of fetal lung growth, and is currently being applied in clinical trials to treat severe forms of pulmonary hypoplasia. The aim of this study was to examine the effect of timing of TO on pulmonary growth and maturation rates. Fetal rabbits (term = 31 d) were subjected to in utero tracheal clipping at 24 (late pseudoglandular stage) or 27 d of gestation (late canalicular/early terminal sac stage). Sham-operated littermates served as controls (C). Animals were killed at time intervals ranging from 1 to 6 d (early group) or 1 to 3 d (late group) after occlusion. Lung growth was measured by computerized stereologic volumetry and 5'-bromo-2'-deoxyuridine (BrdU) pulse labeling. Pneumocyte II population kinetics were analyzed using a combination of anti-surfactant protein-A and BrdU immunohistochemistry and computer-assisted morphometry. Statistical analysis was performed using unpaired Student's t test. Early TO was followed by an initial 3-d stagnation of growth and subsequently a dramatic acceleration of growth (BrdU-labeling index [LI] 10.1 +/- 0. 6% in TO versus 2.7 +/- 0.5% in C at 29 d, P < 0.001). In contrast, late TO induced an immediate and sustained moderate increase of lung growth (BrdU-LI 2.8 +/- 0.9% in TO versus 1.1 +/- 0.2% in C at 30 d, P < 0.05), associated with relatively more pronounced air-space distension. Whereas late TO caused no significant alterations in type II cell density or proliferation, early TO was followed by a marked increase in type II cell proliferation, paradoxically associated with dramatic reduction of type II cell density after 29 d. The effects of intrauterine TO on fetal lung growth and type II cell kinetics critically depend on the gestational age, and thus on the maturity of the lungs at the time of surgery. These findings have important clinical implications with respect to the timing of fetal interventions aimed at promoting lung growth. The fetal rabbit provides an invaluable model to study the mechanics and age dependency of TO-induced lung growth.

The importance of ATP binding and hydrolysis by hsp90 in formation and function of protein heterocomplexes

The chaperone hsp90 is capable of binding and hydrolyzing ATP. Using information on a related ATPase, DNA gyrase B, we selected three conserved residues in hsp90's ATP-binding domain for mutation. Two of these mutations eliminate nucleotide binding, while the third retains nucleotide binding but is apparently deficient in ATP hydrolysis. We first analyzed how these mutations affect hsp90's binding to the co-chaperones p23 and Hop, and to the hydrophobic resin, phenyl-Sepharose. These experiments showed that ATP's effects, specifically, increased affinity for p23 and decreased affinity for Hop and phenyl-Sepharose, are brought on by ATP binding alone. We also tested the ability of hsp90 mutants to assist hsp70, hsp40, and Hop in the refolding of denatured firefly luciferase. While hsp90 is capable of participating in this process in a nucleotide-independent manner, the ability to hydrolyze ATP markedly potentiates hsp90's effect. Finally, we assembled progesterone receptor heterocomplexes with hsp70, hsp40, Hop, p23, and wild type or mutant hsp90. While neither ATP binding nor hydrolysis was necessary to bind hsp90 to the receptor, mature complexes containing p23 and capable of hormone binding were only obtained with wild type hsp90.

The role of apoptosis in normal and accelerated lung development in fetal rabbits

BACKGROUND/PURPOSE

During fetal development, the mammalian lung undergoes progressive parenchymal involution. Intrauterine tracheal occlusion induces accelerated architectural maturation of the fetal lungs associated with depletion of the surfactant-producing type II cells. This study investigates the spatiotemporal pattern of apoptosis during normal fetal lung development and its modulation in tracheal occlusion-induced accelerated fetal lung growth.

METHODS

Fetal rabbit lungs were studied at 25 to 31 days' gestational age (DGA; term, 31 DGA), corresponding to late pseudoglandular through terminal air sac stages of fetal lung development. Intrauterine tracheal ligation (TL) was performed at 24 DGA. TL fetuses were monitored until 29 DGA, a time-point previously shown to coincide with significant type II cell depletion. Apoptotic cells were identified by light and electron microscopy, as well as terminal deoxynucleotidyl transferase-mediated dUTP-FITC nick-end labeling (TUNEL). Epithelial (type I and II) cell apoptosis was studied by TUNEL labeling in conjunction with antisurfactant protein and anticytokeratin immunohistochemistry. DNA fragmentation was analyzed by gel electrophoresis. Sham-operated littermates served as controls.

RESULTS

The number of apoptotic cells progressively increased with advancing lung growth and architectural maturation (apoptotic index [Al] 1.2 +/- 0.7 x 10(-3) at 25 DGA v 4.2 +/- 1.4 x 10(-3) at 31 DGA; P< .05, analysis of variance). In TL fetuses, the apoptotic rate was significantly higher than in non-TL fetuses from the third postligation day on, coinciding with the onset of significantly increased airspace distension (Al 4.9 +/- 1.3 x 10(-3) in TL v2.6 +/- 0.4 x 10(-3) in controls at 29 DGA; P< .05, Student's ttest). Apoptosis occurred in parenchymal cells and in isolated cells within the airspaces. The apoptotic activity of type II cells was significantly higher in TL fetuses than C fetuses at 29 DGA (type II Al 25.5 +/- 6.3 x 10(-3) in TL v2.3 +/- 0.8 x 10(-3) in C; P< .001). Electron microscopic studies confirmed the presence of apoptotic nuclei in interstitial macrophages and in degenerating intraluminal type II cells. DNA analysis showed nucleosomal bands.

CONCLUSIONS

Normal fetal lung development is associated with a progressive increase of epithelial and interstitial apoptotic activity, a process enhanced by TL. Tracheal occlusion induces a significant increase of type II cell apoptosis, which likely contributes to the observed type II cell depletion after TL. We speculate that fetal type II cell apoptosis after TL may be induced by mechanical distension (stretch) of the airspaces.

Achieving National Cholesterol Education Program goals for low-density lipoprotein cholesterol in cardiac patients: importance of diet, exercise, weight control, and drug therapy

OBJECTIVE

To determine how frequently the National Cholesterol Education Program (NCEP) goal of a low-density lipoprotein (LDL) cholesterol level of 100 mg/dL or less is achieved in clinical practice in patients with coronary artery disease and what fraction of patients can achieve this goal without drug therapy.

DESIGN

We examined the results of lipid management in 152 consecutive patients who had completed cardiac rehabilitation after an acute coronary event. Patients were randomized to follow-up by specially trained nurses or by preventive cardiologists, and they were not receiving lipid-lowering drugs at the start of the study.

MATERIAL AND METHODS

Patients were given aggressive diet and exercise recommendations and lipid-lowering drugs in accordance with NCEP guidelines. Follow-up was continued for a mean of 526 days after the first lipid assessment subsequent to the coronary event. Multiple logistic regression analysis was used to identify independent predictors of a final LDL cholesterol level of 100 mg/dL or less.

RESULTS

Of the study group, 39% achieved the NCEP goal LDL cholesterol level of 100 mg/dL or less. Characteristics of the patients with LDL cholesterol levels of 100 mg/dL or less in comparison with those with LDL cholesterol levels of more than 100 mg/dL included a greater frequency of drug therapy (65% versus 38%), more rigorous dietary compliance, longer follow-up (586 +/- 317 days versus 493 +/- 264 days), more favorable weight change (-0.3 +/- 4.9 kg versus +1.7 +/- 5.0 kg), and more extensive weekly exercise (183 +/- 118 minutes versus 127 +/- 107 minutes).

CONCLUSION

The registered nurses managed the lipids of these patients as effectively as did the preventive cardiologists. Appropriate drug therapy was the most important factor in achieving an LDL cholesterol level of 100 mg/dL or less, but 35% of patients attaining this NCEP goal were not receiving drug therapy. Exercise, dietary compliance, and weight loss were also important factors.