Rationale and design of a multisite randomized clinical trial examining an integrated behavioral treatment for veterans with co-occurring chronic pain and opioid use disorder: The pain and opioids integrated treatment in veterans (POSITIVE) trial

BACKGROUND

Chronic pain and opioid use disorder (OUD) individually represent a risk to health and well-being. Concerningly, there is evidence that they are frequently co-morbid. While few treatments exist that simultaneously target both conditions, preliminary work has supported the feasibility of an integrated behavioral treatment targeting pain interference and opioid misuse. This treatment combined Acceptance and Commitment Therapy (ACT) and Mindfulness-Based Relapse Prevention (ACT+MBRP). This paper describes the protocol for the adequately powered efficacy study of this integrated treatment.

METHODS

A multisite randomized controlled trial will examine the efficacy of ACT+MBRP in comparison to a parallel education control condition, focusing on opioid safety and pain education. Participants include veterans (n = 160; 21-75 years old) recruited from three Veterans Administration (VA) Healthcare Systems with chronic pain who are on a stable dose of buprenorphine. Both conditions include twelve weekly 90 min group sessions delivered via telehealth. Primary outcomes include pain interference (Patient Reported Outcome Measurement Information System - Pain Interference) and hazardous opioid use (Current Opioid Misuse Measure), which will be examined at the end of the active treatment phase and through 12 months post-intervention. Secondary analyses will evaluate outcomes including pain intensity, depression, pain-related fear, and substance use, as well as treatment mechanisms.

CONCLUSION

This study will determine the efficacy of an integrated behavioral treatment program for pain interference and hazardous opioid use among veterans with chronic pain and OUD who are prescribed buprenorphine, addressing a critical need for more integrated treatments for chronic pain and OUD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04648228.

Dysnatremia is a Predictor for Morbidity and Mortality in Hospitalized Patients with COVID-19

CONTEXT

Dysnatremia is an independent predictor of mortality in patients with bacterial pneumonia. There is paucity of data about the incidence and prognostic impact of abnormal sodium concentration in patients with coronavirus disease 2019 (COVID-19).

OBJECTIVE

This work aimed to examine the association of serum sodium during hospitalization with key clinical outcomes, including mortality, need for advanced respiratory support and acute kidney injury (AKI), and to explore the role of serum sodium as a marker of inflammatory response in COVID-19.

METHODS

This retrospective longitudinal cohort study, including all adult patients who presented with COVID-19 to 2 hospitals in London over an 8-week period, evaluated the association of dysnatremia (serum sodium < 135 or > 145 mmol/L, hyponatremia, and hypernatremia, respectively) at several time points with inpatient mortality, need for advanced ventilatory support, and AKI.

RESULTS

The study included 488 patients (median age, 68 years). At presentation, 24.6% of patients were hyponatremic, mainly due to hypovolemia, and 5.3% hypernatremic. Hypernatremia 2 days after admission and exposure to hypernatremia at any time point during hospitalization were associated with a 2.34-fold (95% CI, 1.08-5.05; P = .0014) and 3.05-fold (95% CI, 1.69-5.49; P < .0001) increased risk of death, respectively, compared to normonatremia. Hyponatremia at admission was linked with a 2.18-fold increase in the likelihood of needing ventilatory support (95% CI, 1.34-3.45, P = .0011). Hyponatremia was not a risk factor for in-hospital mortality, except for the subgroup of patients with hypovolemic hyponatremia. Sodium values were not associated with the risk for AKI and length of hospital stay.

CONCLUSION

Abnormal sodium levels during hospitalization are risk factors for poor prognosis, with hypernatremia and hyponatremia being associated with a greater risk of death and respiratory failure, respectively. Serum sodium values could be used for risk stratification in patients with COVID-19.

Abnormal Sodium is a Predictor for Respiratory Failure and Mortality in Hospitalized Patients With COVID-19

Background: Hypernatremia and hyponatremia (serum sodium > 145 mmol/L and < 135 mmol/L, respectively) are independent risk factors for excess mortality in patients with bacterial pneumonia. We sought, for the first time, an association of sodium [Na] abnormalities with mortality, need for advanced respiratory support and Acute Kidney Injury (AKI) in hospitalized patients with coronavirus disease 19 (COVID-19). Methods: This retrospective, longitudinal, cohort study included 488 adults, 277 males and 211 females, with a median age of 68 years, who were hospitalized with COVID-19 to two hospitals in London over an 8-week period (February to May 2020). Results: The in-hospital mortality rate was 31.1% with a medial length of stay of 8 days. High [Na] levels at any timepoint during hospital stay were associated with significantly increased mortality rate (56.6% vs 21.1% in patients who remained constantly normonatremic; odds ratio 3.05, 95% CI 1.69-5.49; p<0.0001). On day 3 and on day 6, high [Na] values predicted mortality with an estimated odds ratio of 2.34 (95% CI 1.08 – 5.05, p=0.0014) and 2.40 (95% CI 1.18 - 4.85, p=0.001), respectively. Non-survivors had a significantly higher 5-day rise in serum [Na] when compared to survivors (3.60 mmol/L vs 1.14 mmol/L respectively, p<0.05). Patients with low serum [Na] levels on admission had a 2.18-fold increase (95% CI 1.34-3.46, p=0.001) in the likelihood of needing advanced ventilatory support compared to those with normal [Na] (31.7% vs 17.5%, respectively). However, exposure to hyponatremia at any timepoint, including at presentation or on day 3 or day 5, was not associated with excess risk of

death. AKI affected 37.1% of patients (21.3%, 7.4% and 8.4% stages 1, 2 and 3 respectively) but was not related to serum sodium values. Conclusions: In hospitalized COVD-19 patients, hypernatremia at any timepoint was associated with excess mortality, suggesting that [Na] concentration may facilitate risk stratification. In addition, whilst our data cannot prove causality, these findings highlight the significance of judicious rehydration in such patients.

Longitudinal Study of Prevalence of Sodium Abnormalities in Hospitalized Patients With COVID-19

Background: Sodium abnormalities (dysnatremia) are frequently observed in patients with community-acquired pneumonia and are associated with excess mortality. Data on the prevalence of hyponatremia and hypernatremia (serum sodium [Na] < 135 and > 145 mmol/L respectively) in patients with coronavirus disease 19 (COVID-19) are currently lacking. Methods: The aim of this study was to evaluate the prevalence and etiology of hyponatremia and hypernatremia at several timepoints during hospitalization of COVID-19 patients. This retrospective, longitudinal, observational study included all COVID-19 positive adult patients admitted to two London hospitals over an 8-week period (February to May 2020). Results: Clinic records were reviewed in 488 patients, 277 males (56.8%) and 211 females (43.2%), with a median age of 68 years. Comorbidities were documented in 79.6%, with the commonest being hypertension (45.7%), diabetes mellitus (25%), and chronic kidney disease (16.4%). Prior to admission, 25 patients (5.1%) had pre-existing chronic hyponatremia. At hospital presentation, median [Na] concentration was 137 mmol/L. Dysnatremia was present in 146 patients (29.9%), including 26 (5.3%) with hypernatremia and 120 (24.6%) with hyponatremia, of whom [Na] was 130-134 mmol/L in 90 (18.4%) and < 130 mmol/L in 30 (6.2%). Only 19% of patients with < 130 mmol/L underwent adequate laboratory assessment of the etiology of hyponatremia. Of those, based on a urinary sodium cut-off of 30 mmol/L, hyponatremia was classified as hypovolemia in 75% and non-hypovolemic in 25%. For the remaining hyponatremic cases, using 5 mmol/L as the cut-off value for plasma urea, 55.7% were classified as probable hypovolemic and 44.3% non-hypovolemic hyponatremia. There was an

upward trajectory of [Na] values during hospital stay with a median increase of 2 mmol/L in the first 48 hours following admission. On the fifth day of hospitalization, the prevalence was similar for hypernatremia and hyponatremia (13.8% and 14.1%, respectively). On the tenth day, hypernatremia was more common than hyponatremia (14.2% vs 10.2% respectively). Analysis of [Na] throughout the hospital stay defined four subgroups; 185 patients (37.9%) remained normonatremic throughout hospitalization; 180 (36.9%) had exposure to hyponatremia; 53 (10.9%) were exposed to hypernatremia; and 70 (14.3%) experienced both hypernatremia and hyponatremia. Conclusions: Hyponatremia, usually mild, was common at admission in Covid-19 positive patients, while hypovolemic hyponatremia appeared to be the predominant etiology. During hospital stay, abnormal sodium concentration was recorded in more than two thirds of Covid-19 positive patients. The association of dysnatremia with the outcomes in hospitalized COVID-19 patients warrants further exploration.

Long-term, high-level hepatic secretion of acid α-glucosidase for Pompe disease achieved in non-human primates using helper-dependent adenovirus

Pompe disease (glycogen storage disease type II (GSD-II)) is a myopathy caused by a genetic deficiency of acid α-glucosidase (GAA) leading to lysosomal glycogen accumulation causing muscle weakness, respiratory insufficiency and death. We previously demonstrated in GSD-II mice that a single injection of a helper-dependent adenovirus (HD-Ad) expressing GAA resulted in at least 300 days of liver secretion of GAA, correction of the glycogen storage in cardiac and skeletal muscles and improved muscle strength. Recent reports suggest that gene therapy modeling for lysososomal storage diseases in mice fails to predict outcomes in larger animal models. We therefore evaluated an HD-Ad expressing GAA in non-human primates. The baboons not only tolerated the procedure well, but the results also confirmed that a single dose of the HD-Ad allowed the livers of the treated animals to express and secrete large amounts of GAA for at least 6 months, at levels similar to those achieved in mice. Moreover, we detected liver-derived GAA in the heart, diaphragm and skeletal muscles of the treated animals for the duration of the study at levels that corrected glycogen accumulation in mice. This work validates our proof-of-concept studies in mice, and justifies future efforts using Ad-based vectors in Pompe disease patients.

Patient Characteristics Associated with Use of Monoclonal Antibody Treatment in Women with Metastatic Breast Cancer: A Population-Based Analysis

Introduction: Monoclonal antibodies (MoATB) were FDA approved for the treatment of patients with breast cancer (BrCA) whose tumors over expressed the human epidermal growth factor receptor 2 (HER2) in 1998. We sought to determine if certain patient characteristics and co-morbidities influenced MoATB use in a population-based practice setting of elderly women with metastatic BrCA. Methods: We identified female Medicare beneficiaries aged 66+ years diagnosed with incident metastatic BrCA without prior history for any cancer between 1999 and 2005 in the Surveillance, Epidemiology and End Results cancer registries (SEER). Charlson Co-morbidity index (CCI) and separate conditions within the index were created using linked Medicare claims in the year prior to the BrCA diagnosis. We identified both oral and infused chemotherapy (CH) from the Medicare claims from 1999 to 2006. Patients were categorized into three groups: no CH, MoATB+/-CH, and CH w/out MoATB. We performed bivariate statistics to compare the patient characteristics and comorbidities between the three groups, and the treatments groups only. Results: There were 3,820 women with metastatic BrCA, mean age 77 (SD 7.3) years, 81% were white race, 29% were married and 91% lived in an urban setting. 67% of these women (n=2,562) received no CH, 26% received CH w/out MoATB (n=994) and 7% received MoATB+/-CH (n=264). Overall the CCI was lower for women receiving either treatment as compared to no chemotherapy and between treatment groups for the young old (66-75 years) but not those aged 80+ years. The prevalence of congestive heart failure (CHF) and cerebrovascular disease was significantly lower in women receiving MoATB +/-CH, as compared to only CH, and also lower in both compared to no CH (n=2,462). Few women presenting with COPD or dementia were likely to be treated with either CH and/or MoATB compared to No CH. Other co-morbidity conditions within the CCI were not statistically different between the groups or the cell numbers were too small to analyze. Conclusion: MoATB use in the treatment of metastatic breast cancer steadily increased from 5% in 1999 to 23% in 2004. Use in 2005 was slightly lower but will be recalculated once the 2007 claims are available. In 2008, FDA released a black box warning for trastuzumab, the most frequently prescribed MoATB for BrCA, regarding the potential for the development of cardiomyopathy. Our results suggest that co-morbidities in particular CHF and cerebrovascular disease may influence the decision to use MoATB. Further research is necessary to examine the relationship between co-morbidities and the use of MoATB in the treatment of metastatic breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2057.

Taxane Treatment in Women with Incident Stage IV Breast Cancer

Introduction: The overall benefit of chemotherapy for late stage breast cancer treatment has been demonstrated in clinical trials and “real world” observational studies, but there is less data on chemotherapy use among older women. In addition, estrogen receptor status can influence treatment decisions. Our objective was to explore the clinical and demographic characteristics of women who received chemotherapy, particularly taxanes, in a large population-based cohort of older patients with incident stage IV breast cancer.Methods: Older women (age 66 and over) diagnosed with incident stage IV breast cancer from 1999 to 2005 were identified in the Surveillance, Epidemiology and End Results (SEER) cancer registries. Treatment-related data were linked from Medicare claims. We limited our analysis to ER negative (ER-) women with the assumption that these women would not be receiving tamoxifen as SEER data do not have complete information on receipt of tamoxifen. Receipt of chemotherapy was identified from claims files. Bivariate analyses were performed to compare clinical and demographic characteristics of those who received taxanes, other chemotherapy, or no chemotherapy.Results: Of 3,820 older women diagnosed with incident stage IV breast cancer, 1,518 women (40%) were identified as ER negative, of whom 247 (16%) were treated with taxanes, 312 (21%) with other chemotherapy, and the remainder received neither. Mean age was 78, 84% of the study cohort was white, 27% were married, and 91% lived in urban areas. Fifty four percent of women had HER2 assays performed. Women who received taxanes were substantially younger (Mean=74, SD=5.49) than those who did not (Mean=80, SD=7.79) and had fewer co-morbidities (measured by Charlson co-morbidity index) (bivariate [see above] p=0.0003) than any other group. Individuals who received taxanes were less likely to be married, receive radiation or undergo surgery. Only 8% of those treated with taxanes had 2 or more medical conditions compared to 18% of those receiving other chemotherapy and 74% of those with no chemotherapy. Treatment groups varied in regard to some medical conditions including CHF, cerebrovascular disease, and dementia. For example, only 8% of those receiving taxanes had CHF, compared to 13% among the 'other chemotherapy' group and 78% among those receiving no treatment (bivariate [see above] p=0.0003). A similar trend was revealed with the other medical conditions, with taxane users consistently presenting with lower prevalence for each condition. Interestingly, no one who had dementia received any chemotherapy.Conclusion: Findings from this descriptive study showed that age and co-morbidity were the most important factors associated with receipt of taxanes as well as of other chemotherapy. However, those who received taxanes were the youngest and evidenced the least comorbidity of the 2 groups. Further study is needed to help inform clinicians in making optimum treatment recommendations for their older female patients with incident advanced breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2068.

Chemotherapy Treatment and Survival in Estrogen Receptor Negative Metastatic Breast Cancer: A Population-Based Analysis

Introduction: Although controlled clinical trials have demonstrated a beneficial effect of various chemotherapy regimens on survival in breast cancer (BC), little is known about treatment patterns and survival benefit in the “real world” population of elderly women with metastatic BC. Methods: We identified female Medicare beneficiaries aged ≥66 years with metastatic BC diagnosed from 1999 to 2005 in the Surveillance, Epidemiology and End Results cancer registries (SEER). Patients with a prior history of any cancer were excluded. Treatment-related data were abstracted from linked Medicare claims. Since Medicare claims have incomplete information on oral selective estrogen receptor modulators, we limited our study cohort to estrogen receptor negative (ER-) women. Chemotherapy was defined as the receipt of any chemotherapeutic regimen within 6 months after diagnosis. Initial regimens were characterized based on drugs given during the first 30 days of chemotherapy. We used a continuous-time interval-censored survival analysis to determine the effect of chemotherapy on hazard of any-cause death, controlling for sociodemographic and clinical factors, including proxy measures for performance status. Results: We identified 1518 ER(-) women diagnosed with metastatic BC in SEER. Mean age was 77.6 (SD 7.6) years, 84% were white race and 27% were married at the time of diagnosis. Of the 1518 metastatic ER(-) BC patients, 493 (32%) received chemotherapy. As compared to women who did not receive chemotherapy, women who received chemotherapy were more likely to be younger, married, have lower pre-cancer comorbidity as measured by the Charlson comorbidity index, have seen an oncology specialist and have cancer-directed surgery or radiation prior to chemotherapy. Initial regimens comprised predominantly one (31%) or two (46%) drug classes. The most common regimens were taxanes only (18%), anthracycline+alkylating agents (17%) and antimetabolite+alkylating agent (9%). Overall median followup time was 7 months; 1223 women (81%) died during followup. Median survival time was 5 months among women who did not receive chemotherapy and 15 months among women who received chemotherapy. Chemotherapy was associated with a statistically significant survival benefit (adjusted Hazard Ratio 0.61, 95% confidence interval 0.54, 0.70). Conclusion: In this population-based study of older women, there was a variety of chemotherapy regimens used for metastatic ER(-) BC. Chemotherapy received within 6 months after diagnosis was associated with a 39% reduction in hazard of death. These findings reflect chemotherapy use outside of the clinical trial setting and have important clinical and policy implications for the study of treatments among older women with advanced BC.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2064.

Tryptophan hydroxylase 2 (TPH2) gene variants associated with ADHD

Genetic and pharmacological studies have emphasised the role of serotonin 5-hydroxytryptamine (5-HT) as a possible etiologic factor in the development of attention-deficit hyperactivity disorder (ADHD). Tryptophan hydroxylase (TPH) is a rate-limiting enzyme in the biosynthesis of serotonin from tryptophan. Originally, the TPH gene was thought to be widely expressed, but a second form of TPH, TPH2, was recently identified and the TPH2 gene was found to be solely expressed in the brain. We examined eight single nucleotide polymorphisms (SNP) in the TPH2 gene for association with ADHD in 179 Irish nuclear families. Transmission disequilibrium test analysis revealed significant association between the T allele of marker rs1843809 with the disorder (chi2=12.2, P=0.0006, OR=2.36). Stratifying data by the sex of the transmitting parent showed that this association was enhanced when paternal transmission was considered (OR=3.7). In addition, several haplotypes (all including the associated marker) were associated with ADHD. These preliminary findings suggest that TPH2 is a susceptibility locus for ADHD. Further confirmation, preferably from different ethnic groups, is required to firmly implicate TPH2 in the pathophysiology of ADHD.

Structural requirements for function of yeast GGAs in vacuolar protein sorting, alpha-factor maturation, and interactions with clathrin

The GGAs (Golgi-localized, gamma-ear-containing, ARF-binding proteins) are a family of multidomain adaptor proteins involved in protein sorting at the trans-Golgi network of eukaryotic cells. Here we present results from a functional characterization of the two Saccharomyces cerevisiae GGAs, Gga1p and Gga2p. We show that deletion of both GGA genes causes defects in sorting of carboxypeptidase Y (CPY) and proteinase A to the vacuole, vacuolar morphology, and maturation of alpha-factor. A structure-function analysis reveals a requirement of the VHS, GAT, and hinge for function, while the GAE domain is less important. We identify putative clathrin-binding motifs in the hinge domain of both yeast GGAs. These motifs are shown to mediate clathrin binding in vitro. While mutation of these motifs alone does not block function of the GGAs in vivo, combining these mutations with truncations of the hinge and GAE domains diminishes function, suggesting functional cooperation between different clathrin-binding elements. Thus, these observations demonstrate that the yeast GGAs play important roles in the CPY pathway, vacuole biogenesis, and alpha-factor maturation and identify structural determinants that are critical for these functions.

The molecular machinery for lysosome biogenesis

The lysosome serves as a site for delivery of materials targeted for removal from the eukaryotic cell. The mechanisms underlying the biogenesis of this organelle are currently the subject of renewed interest due to advances in our understanding of the protein sorting machinery. Genetic model systems such as yeast and Drosophila have been instrumental in identifying both protein and lipid components of this machinery. Importantly, many of these components, as well as the processes in which they are involved, are proving conserved in mammals. Other recently identified components, however, appear to be unique to higher eukaryotes. BioEssays 23:333-343, 2001. Published 2001 John Wiley & Sons, Inc.

Lysosome-related organelles

Lysosomes are membrane-bound cytoplasmic organelles involved in intracellular protein degradation. They contain an assortment of soluble acid-dependent hydrolases and a set of highly glycosylated integral membrane proteins. Most of the properties of lysosomes are shared with a group of cell type-specific compartments referred to as 'lysosome-related organelles', which include melanosomes, lytic granules, MHC class II compartments, platelet-dense granules, basophil granules, azurophil granules, and Drosophila pigment granules. In addition to lysosomal proteins, these organelles contain cell type-specific components that are responsible for their specialized functions. Abnormalities in both lysosomes and lysosome-related organelles have been observed in human genetic diseases such as the Chediak-Higashi and Hermansky-Pudlak syndromes, further demonstrating the close relationship between these organelles. Identification of genes mutated in these human diseases, as well as in mouse and Drosophila: pigmentation mutants, is beginning to shed light on the molecular machinery involved in the biogenesis of lysosomes and lysosome-related organelles.

Distinct requirements for the AP-3 adaptor complex in pigment granule and synaptic vesicle biogenesis in Drosophila melanogaster

The AP-3 adaptor protein complex has been implicated in the biogenesis of lysosome-related organelles, such as pigment granules/melanosomes, and synaptic vesicles. Here we compare the relative importance of AP-3 in the biogenesis of these organelles in Drosophila melanogaster. We report that the Drosophila pigmentation mutants orange and ruby carry genetic lesions in the sigma3 and beta3-adaptin subunits of the AP-3 complex, respectively. Electron microscopy reveals dramatic reductions in the numbers of electron-dense pigment granules in the eyes of these AP-3 mutants. Mutant flies also display greatly reduced levels of pigments housed in these granules. In contrast, electron microscopy of retinula cells reveals numerous synaptic vesicles in both AP-3 mutant and wild-type flies, while behavioral assays show apparently normal locomotor ability of AP-3 mutant larvae. Together, these results demonstrate that Drosophila AP-3 is critical for the biogenesis of pigment granules, but is apparently not essential for formation of a major population of synaptic vesicles in vivo.

Defective expression of the mu3 subunit of the AP-3 adaptor complex in the Drosophila pigmentation mutant carmine

The adaptor protein (AP) complexes AP-1, AP-2, and AP-3 mediate coated vesicle formation and sorting of integral membrane proteins in the endocytic and late exocytic pathways in mammalian cells. A search of the Drosophila melanogaster expressed sequence tag (EST) database identified orthologs of family members mammalian medium (mu) chain families mu1, mu2, and mu3, of the corresponding AP complexes, and delta-COP, the analogous component of the coatomer (COPI) complex. The Drosophila orthologs exhibit a high degree of sequence identity to mammalian medium chain and delta-COP proteins. Northern analysis demonstrated that medium chain and delta-COP mRNAs are expressed uniformly throughout fly development. Medium chain and delta-COP genes were cytologically mapped and the mu3 gene was found to localize to a region containing the pigmentation locus carmine (cm). Analysis of genomic DNA of the cm1 mutant allele indicated the presence of a large insertion in the coding region of the mu3 gene and Northern analysis revealed no detectable mu3 mRNA. Light microscopy of the cm1 mutant showed a reduction in primary, secondary, and tertiary pigment granules in the adult eye. These findings provide evidence of a role for mu3 in the sorting processes required for pigment granule biogenesis in Drosophila.

The catalytic mechanism of endoplasmic reticulum signal peptidase appears to be distinct from most eubacterial signal peptidases

Many type I signal peptidases from eubacterial cells appear to contain a serine/lysine catalytic dyad. In contrast, our data show that the signal peptidase complex from the endoplasmic reticulum lacks an apparent catalytic lysine. Instead, a serine, histidine, and two aspartic acids are important for signal peptidase activity by the Sec11p subunit of the yeast signal peptidase complex. Amino acids critical to the eubacterial signal peptidases and Sec11p are, however, positioned similarly along their primary sequences, suggesting the presence of a common structural element(s) near the catalytic sites of these enzymes.

AP-4, a novel protein complex related to clathrin adaptors

Here we report the identification and characterization of AP-4, a novel protein complex related to the heterotetrameric AP-1, AP-2, and AP-3 adaptors that mediate protein sorting in the endocytic and late secretory pathways. The key to the identification of this complex was the cloning and sequencing of two widely expressed, mammalian cDNAs encoding new homologs of the adaptor beta and sigma subunits named beta4 and sigma4, respectively. An antibody to beta4 recognized in human cells an approximately 83-kDa polypeptide that exists in both soluble and membrane-associated forms. Gel filtration, sedimentation velocity, and immunoprecipitation experiments revealed that beta4 is a component of a multisubunit complex (AP-4) that also contains the sigma4 polypeptide and two additional adaptor subunit homologs named mu4 (mu-ARP2) and epsilon. Immunofluorescence analyses showed that AP-4 is associated with the trans-Golgi network or an adjacent structure and that this association is sensitive to the drug brefeldin A. We propose that, like the related AP-1, AP-2, and AP-3 complexes, AP-4 plays a role in signal-mediated trafficking of integral membrane proteins in mammalian cells.

Mapping, genomic organization and promoter analysis of the human prostate-specific membrane antigen gene

Prostate-specific membrane antigen (PSMA) is a 100 kDa type II transmembrane protein with folate hydrolase and NAALAdase activity. PSMA is highly expressed in prostate cancer and the vasculature of most solid tumors, and is currently the target of a number of diagnostic and therapeutic strategies. PSMA is also expressed in the brain, and is involved in conversion of the major neurotransmitter NAAG (N-acetyl-aspartyl glutamate) to NAA and free glutamate, the levels of which are disrupted in several neurological disorders including multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease and schizophrenia. To facilitate analysis of the role of PSMA in carcinoma we have determined the structural organization of the gene. The gene consists of 19 exons spanning approximately 60 kb of genomic DNA. A 1244 nt portion of the 5' region of the PSMA gene was able to drive the firefly luciferase reporter gene in prostate but not breast-derived cell lines. We have mapped the gene encoding PSMA to 11p11-p12, however a gene homologous, but not identical, to PSMA exists on chromosome 11q14. Analysis of sequence differences between non-coding regions of the two genes suggests duplication and divergence occurred 22 million years ago.

Effect of altering the daily herbage allowance to cows in mid lactation on the composition, ripening and functionality of low-moisture, part-skim Mozzarella cheese

Milk was collected from three spring-calving herds, on different daily herbage allowances (DHA) of perennial rye-grass (16, 20 or 24 kg dry matter (DM)/cow for a 17 week period. On five occasions, at weekly intervals in the middle of the period, the three different milks were converted into low-moisture part-skim Mozzarella cheese. Increasing the DHA resulted in significant increases in the concentrations of protein in the cheesemilk (P < 0.05) and cheese whey (P < 0.02). The moisture-adjusted cheese yield increased significantly (P < 0.01) on raising the DHA from 16 to 24 kg grass DM/cow. DHA had no significant effects on any of the gross compositional values of the cheese (although moisture and fat-in-DM levels tended to decrease and increase respectively with increasing DHA). The hardness of the uncooked cheese and functionality of cooked cheese (i.e. melt time, flowability, stretch and viscosity) were not significantly influenced by DHA over the 115 d ripening period at 4 degrees C.

In addition to SEC11, a newly identified gene, SPC3, is essential for signal peptidase activity in the yeast endoplasmic reticulum

Among the three characterized subunits comprising the signal peptidase complex of the yeast Saccharomyces cerevisiae (Sec11p, Spc1p, and Spc2p), only Sec11p is essential for cell growth, signal peptide cleavage, and signal peptidase-dependent protein degradation. Here we report the cloning of the SPC3 gene encoding the homolog to mammalian signal peptidase subunit SPC22/23. We find that Spc3p is also required for cell growth and signal peptidase activity within the yeast endoplasmic reticulum.

Mutations in the arginine-rich protein gene (ARP) in pancreatic cancer

The ARP gene encodes a highly conserved arginine-rich protein from chromosomal band 3p21.1. At the cytogenetic level this region is frequently deleted in a variety of different solid tumors, although not in pancreatic cancer. We have reported the presence of a specific mutation (ATG50-->AGG) or deletion of codon 50 of the ARP gene in different tumor types (Shridhar et al., 1996, 1996a). In the present study, we have observed mutations involving codon 50 in 11 of 37 pancreatic tumors. The frequency of codon 50 mutation is roughly the same in pancreatic tumors as in the other types of tumors previously examined. In addition, we have detected mutations at codon 51 in multiple PCR subclones in two other pancreatic tumors. Mutations in the ARP gene are thus commonly observed in pancreatic cancer, as well as many other cancers.

Aphidicolin-induced FRA3B breakpoints cluster in two distinct regions

The common fragile site at chromosomal band 3p14.2 (FRA3B) is the most sensitive single site in the human genome to induced chromosomal lesions. This fragile site may predispose chromosome 3p to breakage that is commonly observed in lung, renal, and many other cancers. We previously used aphidicolin induction of FRA3B expression in a chromosome 3-only somatic cell hybrid to generate a series of hybrids with breakpoints in the 3p14.2 region. These breakpoints were localized to two distinct clusters, separated by 200 kb, that lie on either side of a region of frequent breakage within FRA3B as observed by FISH analysis. Seven proximal aphidicolin-induced breakpoints were localized at or near the end of a THE element. The THE-1 element is flanked by LINE and Alu repetitive elements. The eight distal aphidicolin-induced breakpoints clustered in a region capable of forming multiple hairpin-like structures. Thus repetitive elements and hairpin-like structures may be responsible for chromosome fragility in this region.

Frequent breakpoints in the region surrounding FRA3B in sporadic renal cell carcinomas

The constitutive fragile site at chromosomal band 3p14.2, FRA3B, is the most active common fragile site in the human genome. We have localized aphidicolin-induced breakpoints to two distinct clusters, separated by 200 Kb, in FRA3B (Paradee et al., 1996). Sequence analysis of these regions identified two polymorphic microsatellite markers immediately adjacent to each of these breakpoint clusters. In this report we have used these two new microsatellites and 14 additional 3p microsatellites to analyse chromosome 3p breakage and loss in 94 sporadic RCC samples, including nonpapillary, papillary and oncocytomas. We have found heterozygous loss of 3p14 sequences in >60% of the RCC samples, including both clear cell and papillary renal cell carcinomas. We have found frequent breakage in the region immediately surrounding FRA3B, demonstrating that FRA3B does play a role in chromosome breakage and loss in RCC. In contrast to other reports, >50% of the papillary tumors also showed LOH of 3p markers. We also observed microsatellite instability (MIN) with most of the tested markers in seven of eight oncocytomas and one of 69 clear cell carcinomas. The MIN in some oncocytomas was of the RER+ (replication error) type I phenotype. None of the five 3p14.2 markers detected any homozygous deletions in tumor samples, but 69/94 (73%) of the tumors had LOH for the region, which includes the recently identified FHIT gene.

Structurally related Spc1p and Spc2p of yeast signal peptidase complex are functionally distinct

Two subunits of the mammalian signal peptidase complex, SPC12 and SPC25, share similar membrane topologies with the majority of each protein oriented toward the cytoplasm. Such similarities may suggest that these proteins perform redundant functions in signal peptidase activity. In the present study, we addressed this issue through analysis of the yeast homologs to SPC12 and SPC25, Spc1p and Spc2p. We show that both Spc1p and Spc2p are nonessential for signal peptidase activity and growth of yeast cells and that null mutations in the genes encoding Spc1p and Spc2p are synthetically lethal with a conditional mutation affecting Sec11p, an essential subunit of yeast signal peptidase. However, a high copy plasmid encoding Spc1p suppresses the conditional sec11 mutation, whereas the corresponding plasmid encoding Spc2p does not suppress sec11. Moreover, Spc2p, but not Spc1p, is important for signal peptidase activity and cell viability at high temperatures. These results indicate that although both Spc1p and Spc2p are noncatalytic, they are functionally distinct. Evidence is also presented that a double mutant lacking Spc1p and Spc2p grows well relative to wild type yeast cells, indicating that the signal peptidase complex missing at least two of its subunits is sufficient for signal peptidase activity in vivo.

The homologue of mammalian SPC12 is important for efficient signal peptidase activity in Saccharomyces cerevisiae

The multisubunit signal peptidase catalyzes the cleavage of signal peptides and the degradation of some membrane proteins within the endoplasmic reticulum (ER). The only subunit of this enzyme functionally examined to date, yeast Sec11p, is related to signal peptidase I from bacteria. Since bacterial signal peptidase is capable of processing both prokaryotic and eukaryotic signal sequences as a monomer, it is unclear why the analogous enzyme in the ER contains proteins unrelated to signal peptidase I. To address this issue, the gene encoding Spc1p, the yeast homologue to mammalian SPC12, is isolated from the yeast Saccharomyces cerevisiae. Spc1p co-purifies and genetically interacts with Sec11p, but unlike Sec11p, Spc1p is not required for cell growth or the proteolytic processing of tested proteins in yeast. This indicates that only a subset of the ER signal peptidase subunits is required for signal peptidase and protein degradation activities in vivo. Through both genetic and biochemical criteria, Spc1p appears, however, to be important for efficient signal peptidase activity.

A gene from human chromosomal band 3p21.1 encodes a highly conserved arginine-rich protein and is mutated in renal cell carcinomas

We have identified a gene, called ARP for Arginine-rich protein, in human chromosomal band 3p21. It is approximately 600 Kb telomeric to the ACY1 locus (Miller et al., 1989) and encodes a previously unidentified 234 amino acid long, highly basic protein. This gene is highly conserved at the DNA and RNA level. It is found in all species including hamster, rat, mouse, bovine and yeast. We have detected a point mutation (ATG50 to AGG) or deletion of ATG50 in 10 of 21 sporadic renal cell carcinomas. The mutable region is in an imperfect trinucleotide repeat in the coding region which is non-polymorphic among 50 normal individuals examined. The point mutation (ATG50 to AGG) or deletion of codon 50 removes a methionine and increases the stretch of arginines encoded by the AGG repeats in the ARP gene.

Endovascular stent placement for pulmonary venous obstruction after Mustard operation for transposition of the great arteries

Stenting of the left pulmonary venous baffle obstruction was successfully performed in a 6 year old girl after the Mustard operation for transposition of the great arteries. She also had stent implantation in both the superior vena cava and inferior vena cava baffle junctions. These procedures were followed by sustained clinical improvement. Angiography showed that all three stents were fully patent a year after the procedure.

A mutation affecting signal peptidase inhibits degradation of an abnormal membrane protein in Saccharomyces cerevisiae

Signal peptidase removes amino-terminal signal peptides from precursor proteins during or immediately following their translocation to the lumen of the endoplasmic reticulum (ER) and may participate in ER degradation, a poorly defined process whereby abnormal proteins are rapidly degraded early in the secretory pathway. Here, the involvement of signal peptidase in ER degradation is examined through the use of two chimeric membrane proteins that lack amino-terminal signal peptides: A189invHD, which contains sequences derived from arginine permease and histidinol dehydrogenase, and AHDK2, containing the ER-resident protein Kar2p fused to the carboxyl terminus of A189invHD. Degradation of approximately 95% of A189invHD is observed in yeast cells expressing enzymatically active signal peptidase, whereas only 60% undergoes rapid degradation in a sec11 mutant bearing a temperature-sensitive mutation in the gene encoding the 18-kDa subunit (Sec11p) of the signal peptidase complex. AHDK2 is proteolyzed in a reaction yielding at least two fragments in wild-type cells and in the sec11 mutant containing a plasmid bearing the SEC11 gene. The proteolytic reaction is catalyzed in a temperature-dependent manner in the sec11 mutant, with AHDK2 remaining stable at the nonpermissive temperature. Using conditional mutants defective in protein translocation into and out of the ER and in vitro protease protection studies, the site of degradation for AHDK2 is localized to the ER lumen. The data therefore indicate (i) A189invHD is degraded through both signal peptidase-dependent and independent processes; (ii) signal peptidase, specifically the Sec11p subunit, is required for the proteolysis of AHDK2; and (iii) the Kar2 fragment at the carboxyl terminus of AHDK2 permits detection of proteolytic intermediates.

Natural protection against HIV-1 infection provided by HIV-2

Significant differences have been observed in the rates of transmission and disease development in human immunodeficiency virus (HIV) types 1 and 2. Because many HIV-2-infected people remain asymptomatic for prolonged periods, the hypothesis that HIV-2 might protect against subsequent infection by HIV-1 was considered. During a 9-year period in Dakar, Senegal, the seroincidence of both HIV types was measured in a cohort of commercial sex workers. Despite a higher incidence of other sexually transmitted diseases (STDs), HIV-2-infected women had a lower incidence of HIV-1 than did HIV-seronegative women, with a relative risk of 0.32 (P = 0.008). An understanding of the cross-protective mechanisms involved may be directly relevant to HIV-1 vaccine development.

Precise localization of aphidicolin-induced breakpoints on the short arm of human chromosome 3

The common fragile site at 3p14.2 (FRA3B) has been described as the most active fragile site in the human genome. This locus may predispose chromosome 3 to specific losses due to deletions and translocations that have been associated with several malignancies, including hereditary renal cell carcinoma. We have previously described induction of breakage around FRA3B using aphidicolin in a somatic cell hybrid whose only human component was a single intact chromosome 3. That work led to the isolation of hybrids with breakpoints in the 3p13-p21.1 region with loss of all sequences distal to their respective breakpoints. In this report we describe the further characterization of the breakpoints in many of these cell lines using newly available molecular markers. We also report the identification of YAC clones that span the breakpoints present in many of these hybrids.

Balloon dilatation of complete obstruction of the superior vena cava after Mustard operation for transposition of great arteries

Balloon dilatation was successfully performed in two patients with complete obstruction of the superior vena cava baffle junction after a Mustard operation for transposition of the great arteries. Evidence for complete relief of obstruction in the first patient, aged 4 years, was obtained by angiography, which showed improved calibre at the site of obstruction and improved haemodynamic pressure measurement after the balloon dilatation. In the second patient, aged 14 years, the relief was incomplete; in this patient a 3 cm long 3 mm diameter Palmaz stent was successfully implanted.

Structure-function analyses for aminoglycoside 3'-phosphotransferase II (APH(3')-II)

Mutant strains containing APH(3')-II were constructed via site-directed mutagenesis of the cloned gene and by random mutagenesis of a strain containing the APH(3')-II gene on a conjugative plasmid. Substitutions at highly conserved amino acid residues produced APH(3') enzymes which in general showed reduced activity and conferred reduced levels of resistance to their substrates. Substitutions at Tyr 218 altered substrate specificity for the enzymes. Random mutagenesis produced plasmid-borne mutations conferring amikacin resistance. Two of these mutations appeared to be localized to the APH(3')-II structural gene.

Molecular characterization of PKU allele prevalent in southern Europe and Ireland

A novel substitution has been characterized in the phenylalanine hydroxylase (PAH) gene that is linked exclusively to mutant haplotype 6, which is prevalent in southern Europe but rare in northern and eastern Europe. It is a G-to-A transition in intron 10, 11 bases from exon 11. This substitution creates an additional AG dinucleotide, which may serve as a cryptic splice acceptor site. Individuals who bear this substitution in the homozygous state have a severe PKU phenotype with pretreatment serum phenylalanine levels over 1200 mumol/liter. The frequency and distribution of this substitution among European populations suggests two possible founding populations, one being Middle Eastern and the other Roman. The use of this substitution as a marker to identify PKU chromosomes will be an invaluable aid to carrier screening and prenatal diagnosis in populations where mutant haplotype 6 is prevalent.

[Percutaneous transvenous antegrade balloon angioplasty in aortic isthmus stenosis]

Balloon angioplasty of native or postoperative coarctation of the aorta has been recommended as an alternative method to surgical treatment. On use of the retrograde approach via the femoral artery, after introduction of the catheter into a vessel of narrow lumen, not infrequently, injury or obstruction was observed. This overview summarizes our experience primarily on use of antegrade balloon angioplasty for coarctation of the aorta, the first description of which was published as a case report in 1986. Between December, 1985, and September, 1987, balloon angioplasty was carried out for native coarctation of the aorta in seven neonates, age two to 30 days. Concomitant cardiovascular anomalies included ventricular septal defect in five, patent ductus arteriosus in five, mitral valve atresia in two and transposition of the great arteries with and without double outlet right ventricle in two (Table 1). Prior to balloon angioplasty for coarctation, in four neonates therapeutic balloon atrial septostomy had been performed. For balloon angioplasty, via the right femoral vein, an end-hole catheter was advanced into the right ventricle. In five neonates, the catheter could be advanced into the ascending aorta directly from the right ventricle or through a ventricular septal defect. In the two other neonates, the catheter was advanced via the foramen ovale and the mitral valve into the left ventricle and the ascending aorta. Pressure was measured by the end-hole catheter as well as in the femoral artery after direct puncture.(ABSTRACT TRUNCATED AT 250 WORDS)

[Percutaneous transluminal balloon dilatation of discrete membranous subvalvular aortic stenosis]

Discrete membranous subaortic stenosis (DMSS) which is localized immediately subvalvular and can be differentiated from fibromuscular stenosis of the left ventricular outflow tract, represents theoretically a well-suited lesion for uncomplicated balloon dilatation. The practical use of balloon dilatation for treatment of DMSS has been reported by two groups [6, 10]. In this overview, we will report our experience with balloon dilatation of DMSS in six children. Between June, 1986 and June, 1987, balloon dilatation of DMSS was carried out in six male children ranging in age from four to ten years (Table 2). In one child, coarctation of the aorta had been present and was previously treated successfully with balloon dilatation. In two children, the aortic valve was thickened with or without stenosis. All children had mild aortic regurgitation. After transvenous right heart catheterization and transarterial left heart catheterization including levocardiography and supraaortic angiography, 50 units of heparin per kilogram of body weight were administered and a guidewire advanced to the left ventricle for positioning of the balloon catheter in the left ventricular outflow tract. The choice of balloon diameter was based on measurement of the angiographically-determined aortic ring diameter (Table 1). Pressure measurements were obtained by means of a diagnostic catheter after the dilatation. No complications were observed either during or immediately after the intervention. After the dilatation, all children were discharged from the hospital to go home. Pressure in the left ventricle was reduced from 225 +/- 55 to 116 +/- 29 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)