Perturbations of the T-cell receptor repertoire in response to SARS-CoV-2 in immunocompetent and immunocompromised individuals

BACKGROUND

Functional T-cell responses are essential for virus clearance and long-term protection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, whereas certain clinical factors, such as older age and immunocompromise, are associated with worse outcome.

OBJECTIVE

We sought to study the breadth and magnitude of T-cell responses in patients with coronavirus disease 2019 (COVID-19) and in individuals with inborn errors of immunity (IEIs) who had received COVID-19 mRNA vaccine.

METHODS

Using high-throughput sequencing and bioinformatics tools to characterize the T-cell receptor β repertoire signatures in 540 individuals after SARS-CoV-2 infection, 31 IEI recipients of COVID-19 mRNA vaccine, and healthy controls, we quantified HLA class I- and class II-restricted SARS-CoV-2-specific responses and also identified several HLA allele-clonotype motif associations in patients with COVID-19, including a subcohort of anti-type 1 interferon (IFN-1)-positive patients.

RESULTS

Our analysis revealed that elderly patients with COVID-19 with critical disease manifested lower SARS-CoV-2 T-cell clonotype diversity as well as T-cell responses with reduced magnitude, whereas the SARS-CoV-2-specific clonotypes targeted a broad range of HLA class I- and class II-restricted epitopes across the viral proteome. The presence of anti-IFN-I antibodies was associated with certain HLA alleles. Finally, COVID-19 mRNA immunization induced an increase in the breadth of SARS-CoV-2-specific clonotypes in patients with IEIs, including those who had failed to seroconvert.

CONCLUSIONS

Elderly individuals have impaired capacity to develop broad and sustained T-cell responses after SARS-CoV-2 infection. Genetic factors may play a role in the production of anti-IFN-1 antibodies. COVID-19 mRNA vaccines are effective in inducing T-cell responses in patients with IEIs.

Multicenter analysis of neutrophil extracellular trap dysregulation in adult and pediatric COVID-19

Dysregulation in neutrophil extracellular trap (NET) formation and degradation may play a role in the pathogenesis and severity of COVID-19; however, its role in the pediatric manifestations of this disease, including multisystem inflammatory syndrome in children (MIS-C) and chilblain-like lesions (CLLs), otherwise known as “COVID toes,” remains unclear. Studying multinational cohorts, we found that, in CLLs, NETs were significantly increased in serum and skin. There was geographic variability in the prevalence of increased NETs in MIS-C, in association with disease severity. MIS-C and CLL serum samples displayed decreased NET degradation ability, in association with C1q and G-actin or anti-NET antibodies, respectively, but not with genetic variants of DNases. In adult COVID-19, persistent elevations in NETs after disease diagnosis were detected but did not occur in asymptomatic infection. COVID-19–affected adults displayed significant prevalence of impaired NET degradation, in association with anti-DNase1L3, G-actin, and specific disease manifestations, but not with genetic variants of DNases. NETs were detected in many organs of adult patients who died from COVID-19 complications. Infection with the Omicron variant was associated with decreased NET levels when compared with other SARS-CoV-2 strains. These data support a role for NETs in the pathogenesis and severity of COVID-19 in pediatric and adult patients.

Multicenter analysis of neutrophil extracellular trap dysregulation in adult and pediatric COVID-19

Dysregulation in neutrophil extracellular trap (NET) formation and degradation may play a role in the pathogenesis and severity of COVID-19; however, its role in the pediatric manifestations of this disease including MIS-C and chilblain-like lesions (CLL), otherwise known as "COVID toes", remains unclear. Studying multinational cohorts, we found that, in CLL, NETs were significantly increased in serum and skin. There was geographic variability in the prevalence of increased NETs in MIS-C, in association with disease severity. MIS-C and CLL serum samples displayed decreased NET degradation ability, in association with C1q and G-actin or anti-NET antibodies, respectively, but not with genetic variants of DNases. In adult COVID-19, persistent elevations in NETs post-disease diagnosis were detected but did not occur in asymptomatic infection. COVID-19-affected adults displayed significant prevalence of impaired NET degradation, in association with anti-DNase1L3, G-actin, and specific disease manifestations, but not with genetic variants of DNases. NETs were detected in many organs of adult patients who died from COVID-19 complications. Infection with the Omicron variant was associated with decreased levels of NETs when compared to other SARS-CoV-2 strains. These data support a role for NETs in the pathogenesis and severity of COVID-19 in pediatric and adult patients.

Summary

NET formation and degradation are dysregulated in pediatric and symptomatic adult patients with various complications of COVID-19, in association with disease severity. NET degradation impairments are multifactorial and associated with natural inhibitors of DNase 1, G-actin and anti-DNase1L3 and anti-NET antibodies. Infection with the Omicron variant is associated with decreased levels of NETs when compared to other SARS-CoV-2 strains.

Antibody responses to the SARS-CoV-2 vaccine in individuals with various inborn errors of immunity

BACKGROUND

SARS-CoV-2 vaccination is recommended in patients with inborn errors of immunity (IEIs); however, little is known about immunogenicity and safety in these patients.

OBJECTIVE

We sought to evaluate the impact of genetic diagnosis, age, and treatment on antibody response to COVID-19 vaccine and related adverse events in a cohort of patients with IEIs.

METHODS

Plasma was collected from 22 health care worker controls, 81 patients with IEIs, and 2 patients with thymoma; the plasma was collected before immunization, 1 to 6 days before the second dose of mRNA vaccine, and at a median of 30 days after completion of the immunization schedule with either mRNA vaccine or a single dose of Johnson & Johnson's Janssen vaccine. Anti-spike (anti-S) and anti-nucleocapsid antibody titers were measured by using a luciferase immunoprecipitation systems method. Information on T- and B-cell counts and use of immunosuppressive drugs was extracted from medical records, and information on vaccine-associated adverse events was collected after each dose.

RESULTS

Anti-S antibodies were detected in 27 of 46 patients (58.7%) after 1 dose of mRNA vaccine and in 63 of 74 fully immunized patients (85.1%). A lower rate of seroconversion (7 of 11 [63.6%]) was observed in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. Previous use of rituximab and baseline counts of less than 1000 CD3+ T cells/mL and less than 100 CD19+ B cells/mL were associated with lower anti-S IgG levels. No significant adverse events were reported.

CONCLUSION

Vaccinating patients with IEIs is safe, but immunogenicity is affected by certain therapies and gene defects. These data may guide the counseling of patients with IEIs regarding prevention of SARS-CoV-2 infection and the need for subsequent boosts.

Positioning human body models for crashworthiness using model order reduction

A new technique to accelerate the positioning of human body models (HBMs) by means of a dimensionality reduction of a database of precomputed simulations is presented. First, a set of important subspace deformation modes which are used to approximate the model's movements observed in the training simulations are computed. In the second step, a convex optimization problem is solved in order to obtain an optimal position of the human body model as described by the user. We apply the proposed method to a new reclined seating position of the Total Human Model for Safety (THUMS, v5).

Cutaneous barrier leakage and gut inflammation drive skin disease in Omenn syndrome

Background

Severe early-onset erythroderma and gut inflammation, with massive tissue infiltration of oligoclonal activated T cells are the hallmark of Omenn syndrome (OS).

Objective

The impact of altered gut homeostasis in the cutaneous manifestations of OS remains to be clarified.

Methods

We analyzed a cohort of 15 patients with OS and the 129Sv/C57BL/6 knock-in Rag2^R229Q/R229Q (Rag2^R229Q) mouse model. Homing phenotypes of circulating lymphocytes were analyzed by flow cytometry. Inflammatory cytokines and chemokines were examined in the sera by ELISA and in skin biopsies by immunohistochemistry and in situ RNA hybridization. Experimental colitis was induced in mice by dextran sulfate sodium salt.

Results

We show that memory/activated T cells from patients with OS and from the Rag2^R229Q mouse model of OS abundantly express the skin homing receptors cutaneous lymphocyte associated antigen and CCR4 (Ccr4), associated with high levels of chemokine C-C motif ligands 17 and 22. Serum levels of LPS are also elevated. A broad T_h1/T_h2/T_h17 inflammatory signature is detected in the periphery and in the skin. Increased Tlr4 expression in the skin of Rag2^R229Q mice is associated with enhanced cutaneous inflammation on local and systemic administration of LPS. Likewise, boosting colitis in Rag2^R229Q mice results in increased frequency of Ccr4⁺ splenic T cells and worsening of skin inflammation, as indicated by epidermal thickening, enhanced epithelial cell activation, and dermal infiltration by T_h1 effector T cells.

Conclusions

These results support the existence of an interplay between gut and skin that can sustain skin inflammation in OS.

How much do we know about the frequency of hybridisation and polyploidy in the Mediterranean region?

Natural hybridisation and polyploidy are currently recognised as drivers of biodiversity, despite early scepticism about their importance. The Mediterranean region is a biodiversity hotspot where geological and climatic events have created numerous opportunities for speciation through hybridisation and polyploidy. Still, our knowledge on the frequency of these mechanisms in the region is largely limited, despite both phenomena are frequently cited in studies of Mediterranean plants. We reviewed information available from biodiversity and cytogenetic databases to provide the first estimates of hybridisation and polyploidy frequency in the Mediterranean region. We also inspected the most comprehensive modern Mediterranean Flora (Flora iberica) to survey the frequency and taxonomic distribution of hybrids and polyploids in Iberian Peninsula. We found that <6% of Mediterranean plants were hybrids, although a higher frequency was estimated for the Iberian Peninsula (13%). Hybrids were concentrated in few families and in even fewer genera. The overall frequency of polyploidy (36.5%) was comparable with previous estimates in other regions; however our estimates increased when analysing the Iberian Peninsula (48.8%). A surprisingly high incidence of species harbouring two or more ploidy levels was also observed (21.7%). A review of the available literature also showed that the ecological factors driving emergence and establishment of new entities are still poorly studied in the Mediterranean flora, although geographic barriers seem to play a major role in polyploid complexes. Finally, this study reveals several gaps and limitations in our current knowledge about the frequency of hybridisation and polyploidy in the Mediterranean region. The obtained estimates might change in the future with the increasing number of studies; still, rather than setting the complete reality, we hope that this work triggers future studies on hybridisation and polyploidy in the Mediterranean region.

Past climate changes facilitated homoploid speciation in three mountain spiny fescues (Festuca, Poaceae)

Apart from the overwhelming cases of allopolyploidization, the impact of speciation through homoploid hybridization is becoming more relevant than previously thought. Much less is known, however, about the impact of climate changes as a driven factor of speciation. To investigate these issues, we selected Festuca picoeuropeana, an hypothetical natural hybrid between the diploid species F. eskia and F. gautieri that occurs in two different mountain ranges (Cantabrian Mountains and Pyrenees) separated by more than 400 km. To unravel the outcomes of this mode of speciation and the impact of climate during speciation we used a multidisciplinary approach combining genome size and chromosome counts, data from an extensive nuclear genotypic analysis, plastid sequences and ecological niche models (ENM). Our results show that the same homoploid hybrid was originated independently in the two mountain ranges, being currently isolated from both parents and producing viable seeds. Parental species had the opportunity to contact as early as 21000 years ago although niche divergence occurs nowadays as result of a climate-driven shift. A high degree of niche divergence was observed between the hybrid and its parents and no recent introgression or backcrossed hybrids were detected, supporting the current presence of reproductive isolation barriers between these species.

Correlation of neonatal intensive care unit performance across multiple measures of quality of care

OBJECTIVES

To examine whether high performance on one measure of quality is associated with high performance on others and to develop a data-driven explanatory model of neonatal intensive care unit (NICU) performance.

DESIGN

We conducted a cross-sectional data analysis of a statewide perinatal care database. Risk-adjusted NICU ranks were computed for each of 8 measures of quality selected based on expert input. Correlations across measures were tested using the Pearson correlation coefficient. Exploratory factor analysis was used to determine whether underlying factors were driving the correlations.

SETTING

Twenty-two regional NICUs in California.

PATIENTS

In total, 5445 very low-birth-weight infants cared for between January 1, 2004, and December 31, 2007.

MAIN OUTCOMES MEASURES

Pneumothorax, growth velocity, health care-associated infection, antenatal corticosteroid use, hypothermia during the first hour of life, chronic lung disease, mortality in the NICU, and discharge on any human breast milk.

RESULTS

The NICUs varied substantially in their clinical performance across measures of quality. Of 28 unit-level correlations, 6 were significant (ρ < .05). Correlations between pairs of measures of quality of care were strong (ρ ≥ .5) for 1 pair, moderate (range, ρ ≥ .3 to ρ < .5) for 8 pairs, weak (range, ρ ≥ .1 to ρ < .3) for 5 pairs, and negligible (ρ < .1) for 14 pairs. Exploratory factor analysis revealed 4 underlying factors of quality in this sample. Pneumothorax, mortality in the NICU, and antenatal corticosteroid use loaded on factor 1; growth velocity and health care-associated infection loaded on factor 2; chronic lung disease loaded on factor 3; and discharge on any human breast milk loaded on factor 4.

CONCLUSION

In this sample, the ability of individual measures of quality to explain overall quality of neonatal intensive care was modest.

A pharmacodynamic study of the P-glycoprotein antagonist CBT-1® in combination with paclitaxel in solid tumors

BACKGROUND

This pharmacodynamic trial evaluated the effect of CBT-1® on efflux by the ATP binding cassette (ABC) multidrug transporter P-glycoprotein (Pgp/MDR1/ABCB1) in normal human cells and tissues. CBT-1® is an orally administered bisbenzylisoquinoline Pgp inhibitor being evaluated clinically. Laboratory studies showed potent and durable inhibition of Pgp, and in phase I studies CBT-1® did not alter the pharmacokinetics of paclitaxel or doxorubicin.

METHODS

CBT-1® was dosed at 500 mg/m2 for 7 days; a 3-hour infusion of paclitaxel at 135 mg/m2 was administered on day 6. Peripheral blood mononuclear cells (PBMCs) were obtained prior to CBT-1® administration and on day 6 prior to the paclitaxel infusion. (99m)Tc-sestamibi imaging was performed on the same schedule. The area under the concentration-time curve from 0-3 hours (AUC(0-3)) was determined for (99m)Tc-sestamibi.

RESULTS

Twelve patients were planned and enrolled. Toxicities were minimal and related to paclitaxel (grade 3 or 4 neutropenia in 18% of cycles). Rhodamine efflux from CD56+ PBMCs was a statistically significant 51%-100% lower (p < .0001) with CBT-1®. Among 10 patients who completed imaging, the (99m)Tc-sestamibi AUC(0-3) for liver (normalized to the AUC(0-3) of the heart) increased from 34.7% to 100.8% (median, 71.9%; p < .0001) after CBT-1® administration. Lung uptake was not changed.

CONCLUSION

CBT-1® is able to inhibit Pgp-mediated efflux from PBMCs and normal liver to a degree observed with Pgp inhibitors studied in earlier clinical trials. Combined with its ease of administration and lack of toxicity, the data showing inhibition of normal tissue Pgp support further studies with CBT-1® to evaluate its ability to modulate drug uptake in tumor tissue.

DISCUSSION

Although overexpression of ABCB1 and other ABC transporters has been linked with poor outcome following chemotherapy efforts to negate that through pharmacologic inhibition have generally failed. This is thought to be a result of several factors, including (a) failure to select patients with tumors in which ABCB1 is a dominant resistance mechanism; (b) inhibitors that were not potent, or that impaired drug clearance; and (c) the existence of other mechanisms of drug resistance, including other ABC transporters. Although an animal model for Pgp has been lacking, recent studies have exploited a Brca1(-/-); p53(-/-) mouse model of hereditary breast cancer that develops sporadic tumors similar to cancers in women harboring BRCA1 mutations. Treatment with doxorubicin, docetaxel, or the poly(ADP-ribose) polymerase inhibitor olaparib brings about shrinkage, but resistance eventually emerges. Overexpression of the Abcb1a gene, the mouse ortholog of human ABCB1, has been shown to be a mechanism of resistance in a subset of these tumors. Treating mice with resistant tumors with olaparib plus the Pgp inhibitor tariquidar resensitized the tumors to olaparib. Although results in this animal model support a new look at Pgp as a target, in this era of "targeted therapies," trial designs that directly assess modulation of drug uptake, including quantitative nuclear imaging, should be pursued before clinical efficacy assessments are undertaken. Such assessment should be performed with compounds that inhibit tissue Pgp without altering the pharmacokinetics of chemotherapeutic agents. This pharmacodynamic study demonstrated that CBT-1®, inhibits Pgp-mediated efflux from PBMCs and normal liver.

A pharmacodynamic study of docetaxel in combination with the P-glycoprotein antagonist tariquidar (XR9576) in patients with lung, ovarian, and cervical cancer

PURPOSE

P-glycoprotein (Pgp) antagonists have been difficult to develop because of complex pharmacokinetic interactions and a failure to show meaningful results. Here we report the results of a pharmacokinetic and pharmacodynamic trial using a third-generation, potent, noncompetitive inhibitor of Pgp, tariquidar (XR9576), in combination with docetaxel.

EXPERIMENTAL DESIGN

In the first treatment cycle, the pharmacokinetics of docetaxel (40 mg/m(2)) were evaluated after day 1 and day 8 doses, which were administered with or without tariquidar (150 mg). (99m)Tc-sestamibi scanning and CD56(+) mononuclear cell rhodamine efflux assays were conducted to assess Pgp inhibition. In subsequent cycles, 75 mg/m(2) docetaxel was administered with 150 mg tariquidar every 3 weeks.

RESULTS

Forty-eight patients were enrolled onto the trial. Nonhematologic grade 3/4 toxicities in 235 cycles were minimal. Tariquidar inhibited Pgp-mediated rhodamine efflux from CD56(+) cells and reduced (99m)Tc-sestamibi clearance from the liver. There was striking variability in basal sestamibi uptake; a 12% to 24% increase in visible lesions was noted in 8 of 10 patients with lung cancer. No significant difference in docetaxel disposition was observed in pairwise comparison with and without tariquidar. Four partial responses (PR) were seen (4/48); 3 in the non-small cell lung cancer (NSCLC) cohort, measuring 40%, 57%, and 67% by RECIST, and 1 PR in a patient with ovarian cancer.

CONCLUSIONS

Tariquidar is well tolerated, with less observed systemic pharmacokinetic interaction than previous Pgp antagonists. Variable effects of tariquidar on retention of sestamibi in imageable lung cancers suggest that follow-up studies assessing tumor drug uptake in this patient population would be worthwhile.

Abstract 3527: A pharmacodynamic study of docetaxel in combination with the p-glycoprotein antagonist, tariquidar (XR9576) in patients with lung, ovarian, and cervical cancer

Purpose: P-glycoprotein (Pgp) antagonists have been difficult to develop because of complex pharmacokinetic interactions and a failure to demonstrate meaningful results. However, data highlighting Pgp-mediated drug efflux continues to be reported. A growing body of evidence suggests that sestamibi uptake in lung cancer correlates with disease response to chemotherapy and has been proposed as a pre-selection technique to identify tumors that will respond to chemotherapy. We report the results of a clinical trial using tariquidar (XR9576), a potent Pgp antagonist, in combination with docetaxel.

Experimental Design: Patients first received either 40 mg/m2 of docetaxel alone or 40 mg/m2 docetaxel administered in combination with 150 mg tariquidar. In the first cycle, the pharmacokinetics of docetaxel were monitored after the day 1 and day 8 doses with or without tariquidar. 99mTc-sestamibi scanning and rhodamine efflux from CD56+ mononuclear cells were performed to establish whether tariquidar modulates Pgp. In subsequent cycles, 75 mg/m2 of docetaxel was administered with 150mg of tariquidar every three weeks.

Results: Forty-eight patients were enrolled onto the trial. Twenty-nine percent of the patients (14/48) had previously treated metastatic non-small cell lung cancer (NSCLC). Three partial responses were seen in the NSCLC cohort, measuring 40%, 57% and 67% reduction in tumor size by RECIST. Two patients remained on study for 7 and 24 months, respectively. Non-hematologic grade 3/4 toxicities in 235 cycles included fatigue (6%), nausea (4%), and diarrhea (1%). Tariquidar blocked Pgp-mediated rhodamine efflux from CD56+ cells and reduced 99mTc-sestamibi clearance from the liver. Sestamibi results were available in 32 of the 48 patients, and an increased area under the curve for the liver was noted, ranging from 5.8% to 251% over the pre-tariquidar scan. A 12% to 25% increase in sestamibi uptake was noted in 8 of 10 patients with lung cancer with visible lesions. A pharmacokinetic analysis evaluating potential interaction between tariquidar and docetaxel will be presented; previous reports suggest minimal interaction with anticancer agents.

Conclusions: Tariquidar is a Pgp antagonist, without significant side effects and much less pharmacokinetic interaction than previous Pgp antagonists. Surrogate studies show increased retention of the Pgp substrate sestamibi following tariquidar in imagable lung cancers. Although the percentage increase was less than 25%, we have previously noted that quantitation by planar sestamibi imaging tends to underestimate actual change in accumulation. While response in this trial was designed as an exploratory endpoint only, three responses among 14 in a heavily pretreated population with NSCLC are somewhat surprising and suggest that a follow-up phase II study may be worthwhile.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3527.

Rapidly cooled horse spermatozoa: Loss of viability is due to osmotic imbalance during thawing, not intracellular ice formation

The cellular damage that spermatozoa encounter at rapid rates of cooling has often been attributed to the formation of intracellular ice. However, no direct evidence of intracellular ice has been presented. An alternative mechanism has been proposed by Morris (2006) that cell damage is a result of an osmotic imbalance encountered during thawing. This paper examines whether intracellular ice forms during rapid cooling or if an alternative mechanism is present. Horse spermatozoa were cooled at a range of cooling rates from 0.3 to 3,000 degrees C/min in the presence of a cryoprotectant. The ultrastructure of the samples was examined by Cryo Scanning Electron Microscopy (CryoSEM) and freeze substitution, to determine whether intracellular ice formed and to examine alternative mechanisms of cell injury during rapid cooling. No intracellular ice formation was detected at any cooling rate. Differential scanning Calorimetry (DSC) was employed to examine the amount of ice formed at different rate of cooling. It is concluded that cell damage to horse spermatozoa, at cooling rates of up to 3,000 degrees C/min, is not caused by intracellular ice formation. Spermatozoa that have been cooled at high rates are subjected to an osmotic shock when they are thawed.

Multiparametric magnetic resonance imaging (MRI) of diffuse intrinsic pontine gliomas (DIPG) after radiation therapy (XRT)

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Background: The diagnosis and treatment of DIPG are based on typical MRI findings because of the inherent risk of biopsy. The standard treatment for this tumor is XRT. The limited ability of standard MRI to distinguish tumor from treatment effect hampers the determination of tumor response and time to progression. The objective of this study is to measure biochemical and physiologic MRI markers in DIPG after XRT that may aid in assessment of response. Methods: Fifteen pediatric patients (5 y, range, 1.8–12) with DIPG involving >50% of the pons and treated with XRT only were evaluated 12–64 days (median 38) following XRT (50.4–67.2 Gy, median 54 Gy) by MRI at 1.5 T. Standard T1, T2, and FLAIR MRI was performed in all cases. In addition, proton MR spectroscopy (MRS) was performed in 10 cases, MRS imaging (1H-MRSI) in 12, dynamic contrast enhanced MRI (DCE-MRI) in 14, and dynamic susceptibility weighted MRI (DSC-MRI) in 9. Ktrans and rCBV were measured using ROIs on enhancing portions of the tumor from the DCE- and DSC-MRI data after kinetic modeling. Results: Tumor area changed following XRT by a median of −29% (range, −61 to +37; SD, 33) and −17% (range, −65 to +101; SD, 45) on T2 and FLAIR, respectively. Enhancement was identified in 15 of 15 patients following XRT, and in only 6 of 15 prior to XRT (P = 0.0039 McNemar’s test). Following XRT, Choline: N-Acetyl Aspartate (CHO:NAA) ratio was 3.2 ± 1.9 by single voxel MRS, and the “worst voxel” CHO:NAA ratio was 3.5 ± 1.5 by 1H-MRSI. Overall, rCBV (1.98 ± 1.30) was elevated relative to normal cerebellum. However in 4 of these cases, rCBV was markedly elevated (>2), 4 were normal (1.0–1.3), and one was markedly reduced (0.6).Similarly, disruption of the blood-tumor barrier was variable across the group. Ktrans, a measure of permeability, ranged from 0.000 to 0.026 s−1, averaging 0.0086 ± 0.0085 s−1. Conclusions: Although all patients had a structurally similar tumor on MRI prior to XRT, significant variability in physiologic and metabolic response to XRT as measured by multiparametric MRI are noted. Presumably this variability represents real biologic differences resulting from differential responses to therapy. Determination of the prognostic significance is ongoing.

No significant financial relationships to disclose.

Cryopreservation of horse semen under laboratory and field conditions using a Stirling Cycle freezer

A Stirling Cycle freezer has been developed as an alternative to conventional liquid nitrogen controlled rate freezers. Horse semen samples were cooled in 0.25 ml straws and 15 ml bags in the Stirling Cycle freezer under laboratory conditions and as a portable device, powered from a car battery. For comparison, straws were frozen in a conventional liquid nitrogen controlled rate freezer. Upon thawing, motility and viability of samples frozen in the Stirling Cycle freezer were not significantly different when compared to samples frozen in the liquid nitrogen freezer. Unlike liquid nitrogen systems, the Stirling Cycle freezer does not pose a contamination risk, can be used in sterile conditions and has no need for a constant supply of cryogen. The freezer has potential for use in veterinary and genetic conservation applications.

Case-controlled study of nursing home residents referred for treatment of vocally disruptive behavior

The aim of this study was to identify factors associated with vocally disruptive behavior (VDB) in nursing home patients referred to aged care services for treatment, using a case-control methodology. Characteristics of the VDB, reasons for referral, perceived causal factors, and psychotropic use were noted. Twenty-five subjects and controls were examined with the Screaming Behavior Mapping Instrument, the Cornell Scale for Depression in Dementia, the Dementia Behavior Disturbance Scale, and measures of cognition, functional capacity, social activities, and emotional reactions of nursing staff. VDB was associated with other disturbed behaviors, depression, anxiety, severe dementia, functional impairment, communication difficulties, use of psychotropic medication, social isolation, and emotional distress in the nursing staff. Reasons for referral may relate more to the stress experienced by nursing home staff in managing VDB than to specific attributes of the VDB itself.

Serum dexamethasone levels after decadron phonophoresis

OBJECTIVE

To determine serum levels of dexamethasone at several intervals after administration of Decadron (dexamethasone sodium phosphate) phonophoresis.

DESIGN AND SETTING

This study was designed as a 2-factor analysis of variance with repeated measures on 1 factor (blood draws). Independent variables were group (gel/sham, gel/ ultrasound, dexamethasone/sham, dexamethasone/ultrasound) and blood draws (pretreatment, posttreatment, 15 minutes, and 30 minutes). The dependent variable was the serum level of dexamethasone.

SUBJECTS

Forty healthy college students (21 males, 19 females; mean age = 22 +/- 1.3 years) with no known drug allergies or current medication use were randomly assigned to 1 of 4 treatment groups. The treatment site was the left forearm.

MEASUREMENTS

After the pretreatment blood draw, a 10- minute ultrasound treatment was administered, followed by a posttreatment blood draw. Two additional blood draws followed at 15-minute intervals. A total of 4 serum samples (5 cc each) from each subject were centrifuged, and the pipetted serum was frozen for later analysis by double antibody radioimmunoassay.

RESULTS

No significant amounts of serum dexamethasone were detected in 12 consecutive samples. Testing of additional samples was, therefore, discontinued.

CONCLUSIONS

Decadron phonophoresis as used in this experiment did not result in detectable serum levels of dexamethasone. More study is needed to validate the efficacy of Decadron phonophoresis on serum dexamethasone levels.

Gestational bleeding, bacterial vaginosis, and common reproductive tract infections: risk for preterm birth and benefit of treatment

OBJECTIVE

To examine associations between bacterial vaginosis and other prevalent lower genital tract infections and clinically recognized first-trimester bleeding; possible independent and joint effects of gestational bleeding and bacterial vaginosis or other prevalent infections on preterm birth and premature rupture of membranes; and effects of antimicrobial treatment on reducing risks of preterm birth among these women.

METHODS

A secondary analysis was conducted of 1100 pregnant women enrolled in a prospective observational study that examined the effects of standardized diagnosis and treatment of lower genital tract infections to prevent preterm birth.

RESULTS

Sixty percent of women with first-trimester bleeding had one or more study infections detected at the initial examination. First-trimester bleeding was associated independently with the presence of bacterial vaginosis (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.0, 2.3), Trichomonas vaginalis (OR 2.3, 95% CI 1.3, 4.2), and Chlamydia trachomatis (OR 2.7, 95% CI 1.4, 5.1). Preterm birth was increased among women with first-trimester bleeding and bacterial vaginosis (relative risk [RR] 4.4, 95% CI 2.0, 9.5) and bacterial vaginosis and T vaginalis (RR 3.0, 95% CI 1.0, 8.8). Systemic antimicrobial treatment reduced the rate of preterm birth among women with bacterial vaginosis without first-trimester bleeding (RR 0.37, 95% CI 0.16, 0.88). Treatment of women with both first-trimester bleeding and bacterial vaginosis reduced preterm birth (RR 0.52, 95% CI 0.18, 1.55), but not significantly.

CONCLUSION

First-trimester bleeding was increased among women with bacterial vaginosis, T vaginalis, C trachomatis, and combinations of these infections. Women with bacterial vaginosis who also experienced first-trimester bleeding were at heightened risk for preterm birth. Treatment of studied infections reduced significantly the risks of preterm birth among women without first-trimester bleeding.

Cysteine proteases of Trichomonas vaginalis degrade secretory leukocyte protease inhibitor

Sexually transmitted diseases, including trichomoniasis, are risk factors for acquisition of human immunodeficiency virus (HIV) infection. Enhancement mechanisms are unknown. Secretory leukocyte protease inhibitor (SLPI) from saliva appears to prevent transmission of HIV through inhibition of virus entry into monocytic cells in vitro. This study was undertaken to determine if secreted cysteine proteases of Trichomonas vaginalis degrade SLPI and render it nonfunctional. It was determined if SLPI levels were decreased in vaginal fluids from pregnant women infected with T. vaginalis. Isolated proteases were incubated with recombinant human SLPI, and the degradation was followed by Western analysis with SLPI antiserum. SLPI levels were measured by ELISA in vaginal fluids from women infected with T. vaginalis and uninfected controls. Cysteine proteases cleaved SLPI and rendered it nonfunctional. Median levels of SLPI from infected patients were 26% of those of controls (P <.005). The degradation of SLPI in association with trichomonal infection may increase the risk of HIV acquisition.

Bone densitometry: comparison of dual energy x-ray absorptiometry to radiographic absorptiometry

OBJECTIVE

To assess the reliability and validity of radiographic absorptiometry of middle phalanges when compared to dual energy x-ray absorptiometry (DEXA) of the spine and hip as an indicator of osteoporosis.

METHODS

DEXA readings from the spine and femur were compared with radiographic absorptiometry measurements obtained the same day in a sample of 50 women (average age 63 yrs; range 23-86).

RESULTS

Both spine and femur DEXA scores were significantly correlated with radiographic absorptiometry scores (R = 0.70 and 0.68, respectively; approximate standard errors 0.08). DEXA scores were used as the standard, defining moderate fracture risk by a standardized t score < -2 and marked risk by t < -3. Using cutpoints of t < -2 for DEXA and t < -3 for standardized radiographic absorptiometry values, the sensitivity to osteopenia was 0.62 for DEXA of the spine and 0.63 for DEXA of the femur, with specificities of 0.90 and 0.96, respectively, at these cutpoints; the corresponding false positive and false negative rates for our cohort of women were 0.19 and 0.24 (spine) and 0.07 and 0.24 (femur). Receiver operating characteristic (ROC) curves were plotted, varying DEXA measurement site from spine to femur and standardized cutoff from -2 to -3; the areas under the resulting ROC curves ranged from 0.82 to 0.91.

CONCLUSIONS

Radiographic absorptiometry holds promise as a practical method for screening for osteoporosis.

Measuring psychosocial aspects of well-being in older community residents: performance of four short scales

Given that the assessment of multiple dimensions of health/well-being can create respondent burden, assessment scales that are both effective and brief hold great attraction. In this study, we used Cronbach's alpha and correlational methods, including factor analysis, to evaluate the performance of four short scales measuring psychosocial aspects of well-being (depression, quality of life, sense of coherence, social support) in two samples of community-dwelling persons aged 75 and over (n = 414, n = 50). All four scales exhibited good range, high internal consistency, strong temporal reliability, and reasonable levels of construct validity. We conclude that they are practical contributors to measuring health in community-based older adults.

Elevated protease activities in human amnion and chorion correlate with preterm premature rupture of membranes

OBJECTIVES

The mechanism(s) of preterm premature rupture of fetal membranes resulting in preterm birth remains unknown. Studies suggest that fetal membranes are susceptible to weakening by protease attack and that collagenases may be active at the site of rupture. In this study fetal membranes from women delivered after preterm premature rupture of membranes were compared with control membranes and analyzed qualitatively and quantitatively for protease activities.

STUDY DESIGN

Fourteen membranes from women with preterm premature rupture of membranes and nine membranes from women delivered preterm without premature rupture of membranes or otherwise normal women delivered at term vaginally or by cesarean section were studied. Zymogram gel electrophoresis with gelatin incorporation was used to assess the number and apparent molecular weights of protease activities. Functional and quantitative studies of protease activity were measured by fluorescent substrate cleavage.

RESULTS

Zymogram gel electrophoresis studies demonstrated the presence of five to seven different protease bands in preterm premature rupture of membranes samples, whereas control membranes demonstrated only one to three protease bands. Fluorescent studies of protease activity demonstrated a 10- to 40-fold increase in activity in membranes from women with preterm premature rupture of membranes compared with normal control membranes. Studies with protease inhibitors suggest that most of the activity is due to metalloproteinases.

CONCLUSION

In membranes from women with preterm premature rupture of membranes there appears to be a general increase in the amount of protease activity and increased numbers of putatively different proteases. Increased activity or deregulated protease control may mediate preterm premature rupture of membranes and be a potentially remediable cause of preterm birth.

Prevention of premature birth by screening and treatment for common genital tract infections: results of a prospective controlled evaluation

OBJECTIVE

Our purpose was to analyze (1) the effects of prevalent lower reproductive tract infections and (2) the effect of systematic diagnosis and treatment to reduce risks of early pregnancy loss (< 22 weeks), preterm premature rupture of membrances, and overall preterm birth.

STUDY DESIGN

A prospective, controlled treatment trial was conducted on 1260 women. During the first 7 months of the program (observation, phase I), women were examined at initiation of prenatal care for a panel of lower genital tract microorganisms and bacterial vaginosis. Women were followed up with reexaminations at 22 to 29 weeks and after 32 weeks' gestation. The recommended treatments of the Centers for Disease Control (i.e., 300 mg of clindamycin orally twice daily for 7 days for bacterial vaginosis) were used for infected women during the second 8 months of the study (treatment, phase II). Data were analyzed according to intent to treat by means of univariate and multivariate methods.

RESULTS

Overall, presence of bacterial vaginosis (32.5%) at enrollment was associated with pregnancy loss at < 22 weeks' gestation (relative risk 3.1, 95% confidence interval 1.4 to 6.9). Among women in the observation phase bacterial vaginosis was associated with increased risk of both preterm birth (relative risk 1.9, 95% confidence interval 1.2 to 3.0) and preterm premature rupture of membranes (relative risk 3.5, 95% confidence interval 1.4 to 8.9). Within this population (phase I) 21.9% of preterm birth overall (43.8% premature rupture of membranes) is estimated as attributable to bacterial vaginosis. Among women with bacterial vaginosis phase II (treatment) was associated with reduced preterm birth (relative risk 0.5, 95% confidence interval 0.3 to 0.9); there was a similar reduction for women with preterm premature rupture of membranes (relative risk 0.5, 95% confidence interval 0.2 to 1.4). Women with both bacterial vaginosis and trichomoniasis were at highest risk of preterm birth (28%); treatment of both conditions (phase II) reduced preterm birth (17%) but did not eliminate this risk. Earlier patient enrollment and oral antibiotic treatment were associated with reduced preterm birth.

CONCLUSIONS

This prospective, controlled trial confirms that the presence of bacterial vaginosis is associated with increased risks of pregnancy loss at < 22 weeks, preterm premature rupture of membranes, and preterm birth. Orally administered clindamycin treatment is associated with a 50% reduction of bacterial vaginosis-linked preterm birth and preterm premature rupture of membranes. Women at risk for preterm birth or preterm premature rupture of membranes because of bacterial vaginosis or common genital tract infections should be screened, treated, reevaluated for cure, and re-treated if necessary.

Detection of Trichomonas vaginalis in pregnant women with the InPouch TV culture system

Trichomonas vaginalis causes a common genitourinary infection which is frequently asymptomatic. At present, pregnant women are not usually screened for the infection unless they are symptomatic. In the present study, we screened and obtained samples for culture from all pregnant women attending a prenatal clinic with the InPouch TV culture system and compared results with those of standard culture in Diamond's medium and slide wet mount examination. The InPouch TV culture system was as reliable as Diamond's medium in detecting T. vaginalis and may be useful and effective in a pregnancy clinic setting.

Association of cervicovaginal infections with increased vaginal fluid phospholipase A2 activity

OBJECTIVE

The purpose of this study was to determine if phospholipase A2 was detectable within vaginal fluid and to correlate its presence with the presence of common lower genital tract infection or microbial conditions.

STUDY DESIGN

Pregnant women were examined at the first prenatal visit with standard clinical evaluations and microbiologic cultures or tests. Vaginal fluid samples were evaluated for phospholipase A2 activity by means of a standardized enzyme fluorometric assay. Data were stratified to control for coexisting infections.

RESULTS

Phospholipase A2 activity was detected among 29.8% of women and was independently associated with the presence of bacterial vaginosis (p < 0.001), Trichomonas. vaginalis (p < 0.04), and Chlamydia trachomatis (p < 0.02). The percentage of women with phospholipase A2 activity and the level of activity was increased in the presence of more than one infection.

CONCLUSIONS

Elevated reproductive tract phospholipase A2 concentrations among pregnant women may play roles in the pathogenesis of preterm labor and birth. Identification of pregnant women with increased concentrations in vaginal fluid may allow for development of effective intervention strategies to reduce the risk of preterm birth.

Hospital characteristics and quality of care

OBJECTIVE

To compare quality of care measured by explicit criteria, implicit review, and sickness-adjusted outcomes at different types of hospitals.

DESIGN

Further analysis of data retrospectively abstracted from medical records to evaluate the effects of prospective payment on quality of care for hospitalized Medicare patients.

SETTING

Hospitals in five states were sampled to represent the national Medicare admissions along many dimensions.

PATIENTS

A total of 14,008 elderly patients with one of the following five diseases: congestive heart failure, acute myocardial infarction, pneumonia, stroke, or hip fracture. These patients were randomly sampled from those with these diseases in 297 hospitals in two time periods, 1981 to 1982 and 1985 to 1986.

OUTCOME MEASURES

Explicit criteria, implicit review, and mortality within 30 days of admission adjusted for sickness at admission.

RESULTS

Quality of care ratings for hospital types are similar using explicit criteria, implicit review, and outcomes adjusted for sickness at admission. Quality differences between types of hospitals were large, with the lowest group estimated to have four percentage points higher mortality than major teaching hospitals in a cohort of patients with average mortality of 16%. Quality varies from state to state, but teaching, larger, and more urban hospitals have better quality in general than nonteaching, small, and rural hospitals. Hospital quality persists over time, but small nonteaching hospitals narrowed the gap with better quality hospitals between 1981 and 1986.

CONCLUSIONS

The different measures led to consistent and plausible relationships between quality and hospital characteristics. Thus, valid information about hospital quality can be obtained. We need to develop ways to use such information to improve care.

Cross-validation performance of mortality prediction models

Mortality prediction models hold substantial promise as tools for patient management, quality assessment, and, perhaps, health care resource allocation planning. Yet relatively little is known about the predictive validity of these models. We report here a comparison of the cross-validation performance of seven statistical models of patient mortality: (1) ordinary-least-squares (OLS) regression predicting 0/1 death status six months after admission; (2) logistic regression; (3) Cox regression; (4-6) three unit-weight models derived from the logistic regression, and (7) a recursive partitioning classification technique (CART). We calculated the following performance statistics for each model in both a learning and test sample of patients, all of whom were drawn from a nationally representative sample of 2558 Medicare patients with acute myocardial infarction: overall accuracy in predicting six-month mortality, sensitivity and specificity rates, positive and negative predictive values, and per cent improvement in accuracy rates and error rates over model-free predictions (i.e., predictions that make no use of available independent variables). We developed ROC curves based on logistic regression, the best unit-weight model, the single best predictor variable, and a series of CART models generated by varying the misclassification cost specifications. In our sample, the models reduced model-free error rates at the patient level by 8-22 per cent in the test sample. We found that the performance of the logistic regression models was marginally superior to that of other models. The areas under the ROC curves for the best models ranged from 0.61 to 0.63. Overall predictive accuracy for the best models may be adequate to support activities such as quality assessment that involve aggregating over large groups of patients, but the extent to which these models may be appropriately applied to patient-level resource allocation planning is less clear.

Studying the effects of the DRG-based prospective payment system on quality of care. Design, sampling, and fieldwork

We have conducted a nationally representative before-after study of the effects of the diagnosis related groups-based prospective payment system (PPS) on quality of in-hospital care for aged Medicare patients. We used a pre-post design with multiple time points in both the pre-PPS (calendar years 1981 and 1982) and post-PPS (July 1985 through June 1986) periods. We gathered clinically detailed data from medical records of patients with one of six diseases and supplemented these data with postdischarge information from Health Care Financing Administration files. We used a stratified multistage cluster sampling design with data gathered on 16,758 patients chosen from 297 hospitals in 30 areas in five states. Our hospital participation rate was 97%; we successfully accessed 96% of the medical records we requested; and our mean item-level reliability score was 0.80. Our sample matches the nation closely on hospital urbanicity, size, teaching status, ownership, and percentages of Medicare and Medicaid patients, and patient demographics and mortality.

Measuring quality of care with explicit process criteria before and after implementation of the DRG-based prospective payment system

We developed explicit process criteria and scales for Medicare patients hospitalized with congestive heart failure, myocardial infarction, pneumonia, cerebrovascular accident, and hip fracture. We applied the process scales to a nationally representative sample of 14,012 patients hospitalized before and after the implementation of the diagnosis related group-based prospective payment system. For the four medical diseases, a better process of care resulted in lower mortality rates 30 days after admission. Patients in the upper quartile of process scores had a 30-day mortality rate 5% lower than that of patients in the lower quartile. The process of care improved after the introduction of the prospective payment system; eg, better nursing care after the introduction of the prospective payment system was associated with an expected decrease in 30-day mortality rates in pneumonia patients of 0.8 percentage points, and better physician cognitive performance was associated with an expected decrease in 30-day mortality rates of 0.4 percentage points. Overall, process improvements across all four medical conditions were associated with a 1 percentage point reduction in 30-day mortality rates after the introduction of the prospective payment system.

Prospective payment system and impairment at discharge. The 'quicker-and-sicker' story revisited

Since the introduction of the prospective payment system (PPS), anecdotal evidence has accumulated that patients are leaving the hospital "quicker and sicker." We developed valid measures of discharge impairment and measured these levels in a nationally representative sample of patients with one of five conditions prior to and following the PPS implementation. Instability at discharge (important clinical problems usually first occurring prior to discharge) predicted the likelihood of postdischarge deaths. At 90 days postdischarge, 16% of patients discharged unstable were dead vs 10% of patients discharged stable. After the PPS introduction, instability increased primarily among patients discharged home. Prior to the PPS, 10% of patients discharged home were unstable; after the PPS was implemented, 15% were discharged unstable, a 43% relative change. Efforts to monitor the effect of this increase in discharge instability on health should be implemented.

The effects of the DRG-based prospective payment system on quality of care for hospitalized Medicare patients. An introduction to the series

In 1985, we began a 4-year evaluation of the effects of the diagnosis related groups-based prospective payment system on quality of care for hospitalized Medicare patients. This article provides an overview of the study's background, aims, design, and methods. We used a clinically detailed review of the medical record supplemented by data on postdischarge outcomes drawn from the files of the Health Care Financing Administration and fiscal intermediaries to (1) compare outcomes of care after adjustment for sickness at admission, (2) assess the process of in-hospital care and relationships between processes and outcomes, and (3) assess status at discharge for a nationally representative sample of patients hospitalized before and after prospective payment was implemented.

Changes in sickness at admission following the introduction of the prospective payment system

We developed disease-specific measures of sickness at admission based on medical record data to study mortality of Medicare patients with one of five conditions (congestive heart failure, acute myocardial infarction, cerebrovascular accident, pneumonia, and hip fracture). We collected an average of 73 sickness variables per disease, but our final sickness-at-admission scales use, on average, 19 variables. These scales are publicly available, and explain 25% of the variance in 30-day postadmission mortality for patients with acute myocardial infarction, pneumonia, or cerebrovascular accident. Sickness at admission increased following the introduction of the prospective payment system (PPS). For our five diseases combined, the 30-day mortality to be expected because of sickness at admission was 1.0% higher in the 1985-1986 period than in the 1981-1982 period (16.4% vs 15.4%), and the expected 180-day mortality was 1.6% higher (30.1% vs 28.5%). Studies of the effects of PPS on mortality must take this increase in sickness at admission into account.

Comparing outcomes of care before and after implementation of the DRG-based prospective payment system

We compared patient outcomes before and after the introduction of the diagnosis related groups (DRG)-based prospective payment system (PPS) in a nationally representative sample of 14,012 Medicare patients hospitalized in 1981 through 1982 and 1985 through 1986 with one of five diseases. For the five diseases combined; length of stay dropped 24% and in-hospital mortality declined from 16.1% to 12.6% after the PPS was introduced (P less than .05). Thirty-day mortality adjusted for sickness at admission was 1.1% lower than before (16.5% pre-PPS, 15.4% post-PPS; P less than .05), and 180-day adjusted mortality was essentially unchanged at 29.6% pre-vs 29.0% post-PPS (P less than .05). For patients admitted to the hospital from home, 4% more patients were not discharged home post-PPS than pre-PPS (P less than .05), and an additional 1% of patients had prolonged nursing home stays (P less than .05). The introduction of the PPS was not associated with a worsening of outcome for hospitalized Medicare patients. However, because our post-PPS data are from 1985 and 1986, we recommend that clinical monitoring be maintained to ensure that changes in prospective payment do not negatively affect patient outcome.

Changes in quality of care for five diseases measured by implicit review, 1981 to 1986

We measured quality of care before and after implementation of the prospective payment system. We developed a structured implicit review form and applied it to a sample of 1366 Medicare patients with congestive heart failure, acute myocardial infarction, pneumonia, cerebrovascular accident, or hip fracture who were hospitalized in 1981-1982 or 1985-1986. Very poor quality of care was associated with increased death rates 30 days after admission (17% with very good care died vs 30% with very poor care). The quality of medical care improved between 1981-1982 and 1985-1986 (from 25% receiving poor or very poor care to 12%), although more patients were judged to have been discharged too soon and in unstable condition (7% vs 4%). Except for discharge planning processes, the quality of hospital care has continued to improve for Medicare patients despite, or because of, the introduction of the prospective payment system with its accompanying professional review organization review.

Quality of care before and after implementation of the DRG-based prospective payment system. A summary of effects

In this series we have described changes in the quality of care that have occurred in the treatment of hospitalized elderly Medicare patients with one of five conditions between 1981-1982 and 1985-1986. In this article we report on a mortality analysis, patient and hospital subgroup comparisons, and time series studies we have conducted in an attempt to determine whether changes in quality of care can be linked causally to the introduction of the prospective payment system. Based on these analyses we conclude that (1) mortality following hospitalization has been unaffected by the introduction of the prospective payment system, and improvements in in-hospital processes of care that began prior to the prospective payment system have continued after its introduction, but (2) the prospective payment system has increased the likelihood that a patient will be discharged home in an unstable condition. We recommend that efforts to correct this problem be intensified and that clinical monitoring of the impact of the prospective payment system continue as hospital cost-containment pressures intensify.