Abstract PD3-05: Co-occurring gain-of-function mutations in HER2 and HER3 cooperate to enhance HER2/HER3 binding, HER-dependent signaling, and breast cancer growth

ERBB2, the gene encoding HER2, is mutated in 2-4% of breast cancers. The HER2 tyrosine kinase inhibitor neratinib has shown clinical activity against breast cancers harboring HER2 activating mutations, suggesting these tumors depend on HER2 signaling. Co-occurring HER2 and HER3 (ERBB3) mutations have been reported in patients who respond to neratinib (Hanker et al., Cancer Discov. 2017) suggesting the possibility of cooperativity of both oncogenes. Co-expression of the mutant intracellular domains of HER2 and HER3 in HEK293 cells enhanced phosphorylation of HER3 and ERK compared to expression of either mutant alone, which was blocked by 100 nM neratinib. Interrogation of TCGA, METABRIC, Project GENIE, and Foundation Medicine datasets revealed that gain-of-function mutations in ERBB2 and ERBB3 co-occur with a statistically significant frequency. For example, in GENIE, ERBB2 mutations co-occur with mutations in ERBB3 (8.3% of ERBB2-mutant vs 2.3% of ERBB2 WT; q=1.37x10-10).

We hypothesized that co-occurring mutations in HER2 and HER3 cooperate to enhance HER2 signaling and dependence and breast cancer progression.

Thirty-four unique breast cancers were found to harbor co-occurring mutations in HER2 and HER3, the most common of which were ERBB2L755S/ERBB3E928G (n=10), ERBB2V777L/ERBB3E928G(n=6), and ERBB2L869R/Q/ERBB3E928G (n=4). Using co-immunoprecipitation assays with HER2 and HER3 antibodies in transfected HEK293 cells, we found that co-expression of HER3E928G with wild type (WT) HER2, or co-expression of HER2L755S or HER2L869R with HER3WT, slightly increased HER2-HER3 dimerization. However, binding was strongest between double mutants. This was accompanied by the highest levels of Y1289 p-HER3 in cells expressing both HER3E928G and each HER2L755S, HER2V777L, or HER2L869R compared to cells expressing each HER2 or HER3 mutant with a respective WT heterodimer partner. Structural modeling of the HER2L869R/HER3E928G double-mutant predicted that the HER3 mutation, located at the dimer interface, may enhance heterodimerization of the kinase domains through decreased bulk and electrostatic repulsion. We also noted that the HER2L755S mutation is predicted to be in close proximity to HER3E928G (<4 Å) and may impact binding affinity. Investigation of the structural basis for the enhanced binding of other double mutants is in progress.

MCF7 “knock-in” cells incorporating HER2L755S, HER2V777L, or HER2L869R (or HER2WT) were stably transduced with HER3E928G or HER3WT. Co-expression of double mutants strongly enhanced estrogen-independent growth in 3D Matrigel over cells expressing either mutant alone. We are currently testing inhibitors of HER2/HER3 signaling, including neratinib ± trastuzumab, trastuzumab + pertuzumab, and the ERBB1-3 antibody mixture Sym013, to determine therapeutic strategies to block the cooperative growth induced by co-occurring HER2 and HER2 mutations.

Conclusions: Co-expression of mutant HER2 and mutant HER3 promotes HER2/HER binding, HER3 phosphorylation, and breast tumor cell proliferation. We aim to identify therapeutic vulnerabilities for patients with co-occurring HER2 and HER3 mutations.

Citation Format: Hanker AB, Koch JP, Ye D, Sliwoski G, Sheehan J, Kinch LN, Red Brewer M, He J, Miller VA, Lalani AS, Cutler, Jr. RE, Croessmann S, Zabransky DJ, Meiler J, Arteaga CL. Co-occurring gain-of-function mutations in HER2 and HER3 cooperate to enhance HER2/HER3 binding, HER-dependent signaling, and breast cancer growth [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-05.

Abstract PD3-06: Neratinib + fulvestrant for HER2-mutant, HR-positive, metastatic breast cancer: Updated results from the phase 2 SUMMIT trial

Background: HER2 mutations define a rare subset of metastatic breast cancer (MBC) with a unique mechanism of oncogenic addiction to HER2 signaling. Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has demonstrated single-agent clinical activity in HER2-mutant MBC. In HER2-mutant, HR+ MBC, neratinib + fulvestrant (N+F) appears synergistic vs single-agent neratinib, possibly due to more complete inhibition of bi-directional signaling between HER2 and estrogen receptors. Here we describe interim efficacy results of the expanded HER2-mutant, HR+ MBC cohort treated with N+F from SUMMIT (NCT01953926).

Methods: HR+ MBC patients (pts) with HER2 mutations documented by local testing received oral neratinib 240mg qd and intramuscular fulvestrant (labeled dose). Intensive loperamide prophylaxis was mandatory during cycle 1. Efficacy endpoints include objective response rate at week 8 (ORR8); confirmed objective response rate (ORR); clinical benefit rate (CBR); duration of response (DOR); progression-free survival (PFS); response was assessed by RECIST 1.1 and/or PET Response Criteria. Genomic profiling from fresh/archival tumor tissues and/or plasma cfDNA was performed retrospectively by next-generation sequencing (MSK-IMPACT).

Results: As of 18 May 2018, 46 HER2-mutant HR+ MBC pts have been treated with N+F. Most pts were pretreated, with 91% having received prior anti-cancer medication for MBC (range 0–10). ORR was 33% and median DOR in the 15 pts with a confirmed response was 9.2 months (95% CI 3.9–18.5). Twenty-four pts had prior fulvestrant exposure, and 19 had received prior CDK4/6i-based therapy. Clinical activity was observed with ORRs of 17% and 26% in prior fulvestrant-treated and prior CDK4/6i-treated pts, respectively. ORRs by HER2 mutation were: V777L 63% (5/8 pts); S310F/Y 67% (4/6 pts); G778_P780dup 50% (3/6 pts). Diarrhea was the most common adverse event (grade 3, 24%; grade 4, 0%). Median cumulative duration of grade 3 diarrhea was 3 days. There were no treatment discontinuations due to diarrhea.

 Neratinib + fulvestrantOutcomeaAll patients (N=46)Prior fulvestrant (N=24)Prior CDK4/6i-based therapy (N=19)ORR8 – n (%)19 (41.3)8 (33.3)7 (36.8)95% CI27.0–56.815.6–55.316.3–61.6ORR – n (%)15 (32.6)4 (16.7)5 (26.3)95% CI19.5–48.04.7–37.49.1–51.2DOR for each responder, months 5.6b; 9.2; 9.6b; 18.55.6b; 5.7b; 9.3; 9.6b; 12.9bCBR – n (%)27 (58.7)11 (45.8)9 (47.4)95% CI43.2–73.025.6–67.224.4–71.1Median (95% CI) time to event,c monthsPFS3.9 (3.6–5.7)3.7 (3.5–12.8)3.9 (1.9–NA)DOR9.2 (3.9–18.5)NANAaFor pts with both RECIST- and PET-evaluable lesions, the best of either RECIST or PET response was used to determine response; the earliest progression by RECIST or PET was used for progression; bPt has not progressed; cKaplan-Meier analysis; NA, not applicable

Conclusions: N+F demonstrates encouraging clinical activity with durable responses in heavily pretreated pts with HER2-mutant, HR+ MBC. Of note, responses were observed in pts who had received prior fulvestrant or CDK4/6 inhibitors. No new safety signals were identified; the rate of diarrhea was similar to single-agent neratinib and not dose limiting. Updated data after additional follow-up and genomic data will be presented.

Citation Format: Smyth LM, Piha-Paul SA, Saura C, Loi S, Lu J, Shapiro GI, Juric D, Mayer IA, Arteaga C, de la Fuente M, Brufksy AM, Mau-Sørensen M, Arnedos M, Moreno V, Sohn J-H, Schwartzberg L, Gonzàlez-Farré X, Cervantes A, Mann G, Shahin S, Cutler, Jr. RE, Eli LD, Xu F, Bagulho T, Lalani AS, Bryce R, Solit DB, Hyman DM, Meric-Bernstam F, Baselga J. Neratinib + fulvestrant for HER2-mutant, HR-positive, metastatic breast cancer: Updated results from the phase 2 SUMMIT trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-06.

Abstract P1-13-08: Extended adjuvant neratinib/fulvestrant blocks ER/HER2 crosstalk and maintains complete responses of ER+/HER2+ tumors following treatment with chemotherapy and anti-HER2 therapy

Background: Neratinib is a potent, irreversible pan-HER tyrosine kinase inhibitor. The phase III trial ExteNET showed improved disease-free survival in patients (pts) with HER2+ breast cancer treated with neratinib vs placebo after trastuzumab-based adjuvant therapy. The benefit from neratinib appeared to be greater in pts with ER+ tumors. Thus, we sought to elucidate mechanisms that may explain the benefit from extended adjuvant therapy with neratinib in pts with ER+/HER2+ breast cancer using a human-in-mouse model that simulates the clinical outcomes seen in ExteNET.

Results: Mice with established ER+/HER2 amplified MDA-361 tumors were treated with trastuzumab (tz) + paclitaxel (pac) for 4 weeks, and then randomized to fulvestrant (fulv) ± neratinib for 4 weeks. All MDA-361 tumors exhibited a prompt and marked reduction in volume after tz/pac treatment; 10 mice achieved a complete response (CR) before receiving 'extended adjuvant' therapy with fulv (n=5) or neratinib/fulv (n=5). A CR was maintained with neratinib/fulv following tz/pac. However, mice treated with fulv alone, relapsed rapidly (p<0.05 at week 8) despite of a complete downregulation of tumor ER levels. In a second experiment, nude mice with established MDA-361 xenografts were treated with pertuzumab/tz/pac for 4 weeks. Following a CR, mice were randomized to neratinib/fulv vs. fulv. Again, mice treated with neratinib/fulv maintained a CR, while mice in the fulv alone arm exhibited tumor progressions within a week. In three ER+/HER2+ cell lines (MDA-361, BT474 and UACC893) but not in ER+/HER– MCF7 cells, treatment with neratinib induced ER reporter transcriptional activity whereas treatment with fulv resulted in an increase in HER2 phosphorylation, suggesting compensatory crosstalk between the ER and HER2 pathways. To further understand the molecular basis of this crosstalk, MDA-361 tumor-bearing mice were treated with either fulv, neratinib or the combination for 7 days, after which tumors were harvested and analyzed using a Nanostring breast cancer ER panel consisting of 196 ER-regulated genes. Compared to vehicle or fulv-treated tumors, tumors treated with neratinib alone and neratinib/fulv showed marked downregulation of cyclin D1 mRNA expression. Similarly, in MDA-361, BT474 and UACC893 cells but not in MCF7 cells, only neratinib/fulv downregulated cyclin D1, P-AKT and P-ERK. Finally, treatment with neratinib/fulv but not fulv alone reduced cyclin D1 transcriptional reporter activity and cyclin D1 protein levels, and induced cell cycle arrest, suggesting double blockade is required to overcome compensatory crosstalk between ER and amplified HER2.

Conclusions: Neratinib/fulv but not fulv alone maintained complete responses of ER+/HER+ tumors following treatment with tz/pac or pertuzumab/tz/pac, reminiscent of the results in ExteNET. Neratinib treatment promoted ER transcriptional activity whereas ER downregulation with fulv was associated with increased HER2 signaling. In ER+/HER2+ breast cancer cells and tumors, neratinib/fulv synergistically inhibited growth, cyclin D1 expression, and AKT and MAPK activation, thus providing a plausible mechanism to explain the results in the ExteNET trial.

Citation Format: Sudhan DR, Schwarz LJ, Guerrero-Zotano AL, Nixon M, Formisano L, Croessmann S, Gonzalez Ericsson PI, Sanders ME, Balko JM, Avogadri-Connors F, Cutler RE, Lalani AS, Bryce R, Auerbach A, Arteaga CL. Extended adjuvant neratinib/fulvestrant blocks ER/HER2 crosstalk and maintains complete responses of ER+/HER2+ tumors following treatment with chemotherapy and anti-HER2 therapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-08.

Abstract PD2-05: Inhibition of mutant HER2 results in synthetic lethality when combined with ER antagonists in ER+/HER2 mutant human breast cancer cells

Background: Human epidermal growth factor receptor 2 (ERBB2 or commonly known as HER2) missense mutations have been reported in 2-4% of breast cancers and occur primarily in the absence of HER2 gene amplification. Based on TCGA, approximately 60% of these tumors are hormone-dependent and express estrogen receptor (ER) a. Among ER+ breast cancers with HER2 missense mutations, more than 80% are in the HER2 kinase domain. We examined herein whether ER+/HER2 mutant breast cancer cells are resistant to anti-estrogen therapies and, thus, whether they should be treated with combined ER and HER2 inhibitors.

Methods: Three common HER2 activating mutations (G309A, L755S, V777L) and wild type (WT) HER2 were incorporated into ER+ MCF7 cells using AAV-mediated homologous recombination. The isogenic incorporation of a heterozygous mutation more accurately represents primary human tumors as compared to transfection and overexpression of exogenous vectors. We examined cell viability and ER transcriptional activity, using an ERE-luciferase reporter, in response to estrogen deprivation and treatment with fulvestrant (a selective ER downregulator) and neratinib (an irreversible, pan-HER tyrosine kinase inhibitor), either alone or in combination. Signaling downstream mutant HER2 was examined by immunoblot analysis. In vivo anti-tumor efficacy of fulvestrant ± neratinib is currently being assessed in ovariectomized athymic mice bearing MCF7/HER2V777L xenografts.

Results: MCF7 cells containing HER2 kinase missense mutations (L755S and V777L), but not cells with HER2WT or an extracellular domain mutation (G309A), were able to proliferate exponentially in estrogen-free medium. MCF7/HER2L755S and MCF7/HER2V777L were also resistant to 1 mM fulvestrant, despite fulvestrant's ability to downregulate ER in these cells. Additionally, MCF7/HER2L755S and MCF7/HER2V777L showed increased levels of pERK and p70S6K. Treatment with 200 nM neratinib potently inhibited growth of MCF7/HER2L755S and MCF7/HER2V777L in estrogen-free conditions and resensitized them to fulvestrant while partially downregulating HER2 levels. Addition of 1 nM estradiol markedly rescued all three HER2 mutant cells from neratinib-induced cell death suggesting that the inhibition of both ER and mutant HER2 is required for tumor cell apoptosis. Using ERE-luc reporter assays, neratinib did not inhibit basal or estrogen-induced ER transcriptional activity or ERα Ser118 phosphorylation, thus not supporting HER2 mutation-to-ER crosstalk in these genetically engineered cells. This result also suggests that the ER and HER2 mutant pathways can operate independently and it is the dual pathway inhibition that results in synthetic lethality.

Conclusions: These data suggest that, in ER+ breast cancers and similar to HER2 gene amplification, HER2 kinase domain mutations induce resistance to antiestrogen therapies. Therefore, we propose simultaneous therapeutic targeting of both ER and HER2 signaling pathways is required for maximal inhibition of ER+ breast cancers also harboring HER2 activating mutations, as is currently being investigated in the phase II SUMMIT trial (NCT01953926).

Citation Format: Croessmann S, Zabransky DJ, Cutler, Jr. RE, Lalani AS, Park BH, Arteaga CL. Inhibition of mutant HER2 results in synthetic lethality when combined with ER antagonists in ER+/HER2 mutant human breast cancer cells [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD2-05.

Abstract P3-03-03: An acquired HER2 T798I gatekeeper mutation induces resistance to neratinib in a patient with HER2 mutant-driven breast cancer

ERBB2, the gene encoding HER2, is mutated in 2-4% of breast cancers. The HER2 irreversible tyrosine kinase inhibitor (TKI) neratinib has shown clinical activity against breast cancer cells harboring HER2 activating mutations. Here, we report for the first time an acquired gatekeeper HER2T798I mutation in a patient with HER2-mutant breast cancer after an initial exceptional response to neratinib.

A patient with ER+/PR+/HER2-negative invasive lobular breast cancer progressing on standard therapy was found to harbor a L869R kinase domain mutation in HER2. HER2L869R is homologous to the known activating mutation EGFRL861R/Q. MCF10A breast epithelial cells expressing HER2L869R displayed enhanced HER2-mediated signaling and were resistant to lapatinib and trastuzumab but sensitive to neratinib. The patient was enrolled in the phase II SUMMIT trial (NCT01953926) and treated with neratinib, achieving a partial response lasting 16 months before developing progression. Next gen sequencing of DNA from both a new skin metastasis and plasma cell-free DNA (cfDNA) identified HER2L869R (8.7% cfDNA), whereas a novel HER2T798I mutation was detected only in plasma at 1.3%. Deep sequencing of pre-therapy tumor tissue and plasma did not detect HER2T798I, suggesting that this mutation arose upon resistance. HER2T798I has not been reported in TCGA, COSMIC, or among plasma samples from 17,345 cancer patients subjected to digital DNA sequencing using the Guardant360 assay.

HER2T798I is homologous to the EGFRT790M, KITT670I and BCR-ABLT315I gatekeeper mutations known to mediate resistance to erlotinib/gefitinib and imatinib. To examine if HER2T798I mediates resistance to neratinib, we employed biochemical and biological assays and molecular modeling of wild-type (WT) HER2 and HER2T798I. Structural modeling showed the increased bulk of the isoleucine at position 798 would result in a steric clash with neratinib, thus reducing drug binding. We stably expressed HER2WT, HER2T798I, HER2L869R and HER2L869R/T798I in MCF10A cells and NR6 mouse fibroblasts. Neratinib (10-100 nM) blocked HER2-mediated signaling in cells expressing HER2WT or HER2L869R but did not in cells expressing HER2T798I. The EGFR irreversible TKI osimertinib (100 nM), which isselective for mutant EGFR (including EGFRT790M) and approved for treatment of NSCLC expressing EGFRT790M, failed to inhibit HER2WT, HER2L869R or HER2T798I. In contrast, either the EGFR/HER2 irreversible TKI afatinib or AZ5104, a metabolite of osimertinib, strongly blocked signaling induced by HER2WT, HER2L869R or HER2T798I. Cells expressing HER2T798M displayed a significantly higher IC50 to neratinib than cells expressing HER2WT, whereas afatinib or AZ5014 were very active against all cells (IC50<10 nM).

Conclusions: The acquisition of a T798I gatekeeper mutation in HER2 upon development of clinical resistance to neratinib in a breast cancer with an initial activating mutation in HER2 strongly suggests that HER2L869R is a driver mutation. We speculate that HER2T798I may arise as a secondary mutation following response to effective HER2 TKIs in other cancers with HER2 activating mutations. Certain irreversible EGFR inhibitors may be effective in patients with HER2-driven breast cancer resistant to neratinib.

Citation Format: Hanker AB, Red Brewer M, Sheehan JH, Koch JP, Lanman R, Hyman DM, Cutler, Jr. RE, Lalani AS, Cross D, Lovly CM, Meiler J, Arteaga CL. An acquired HER2 T798I gatekeeper mutation induces resistance to neratinib in a patient with HER2 mutant-driven breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-03-03.

Abstract P3-05-05: Targeting tumor re-wiring by triple blockade of mTORC1, ERBB and ER signaling pathways in endocrine resistant breast cancer

AIM To target tumor re-wiring by combined mTORC1 inhibition plus hormonal treatment with or without co-blockade of ERBB signaling in endocrine resistant models of human breast cancer (BC).

BACKGROUND Around 80% of BCs are estrogen receptor positive (ER+). Endocrine therapies target estrogenic stimulation of tumor growth but resistance remains problematic. Several strategies have shown that resistance often depends on the acquisition of enhanced cross-talk between ER and growth-factor pathways, allowing the disease to circumvent the need for steroid hormones. We have previously reported the antiproliferative effects of the combination of everolimus (RAD001-mTORC1 inhibitor) with endocrine therapy in resistance models, but potential routes of escape from treatment via ERBB2/3 signaling were observed. We hypothesised that combined targeting of three signaling pathways, namely ER, ERBB and mTORC1 may provide enhanced anti-tumor activity.

METHODS ER+ BC cell lines (MCF7, SUM44 and HCC1428) adapted to long term estrogen-deprivation (LTED) which model relapse on an aromatase inhibitor, along with their wild-type (wt) cell lines were treated with neratinib, a pan-ERBB tyrosine kinase inhibitor, in combination with RAD001 ± estradiol (E2), tamoxifen or fulvestrant. End points included proliferation, cell signaling, cell cycle and effect on ER-mediated transactivation and recruitment by ChIP.

RESULTS All cell lines showed a concentration-dependent decrease in proliferation in response to RAD001 (IC50 0.6-50nM in absence of E2 and 1-10nM in presence of E2). A wide range of IC50 values (300-1000nM) was observed with neratinib treatment in the presence of E2. However, in the absence of E2, wt cell lines showed IC50 values in excess of 1800nM with hormetic dose response curves, in which lower concentrations induced cell proliferation. In contrast, LTED IC50 values ranged between 400-900nM. Combination of either agent with endocrine therapy caused a concentration dependent decrease in proliferation in all wt cell lines and their LTED derivatives, but the maximum effect was observed when a triple combination of RAD001, neratinib and ER-blockade was used. Expression of pS6 was dramatically suppressed by RAD001 ± neratinib in all cell lines tested, whilst neratinib caused a cell line specific reduction in expression of ERBB family proteins. Upregulation of pAKT was observed in all cell lines following treatment with RAD001, indicating both inhibitors were effectively suppressing their respective targets. Combination of RAD001 with neratinib suppressed the upregulation of pAKT and significantly reduced cell cycle progression. In the absence of E2, RAD001 caused a reduction in ER-mediated transcription and decrease in recruitment of ER and the CREB-binding protein (CBP) to the TFF1 promoter. In contrast, neratinib induced a marked increase in ER-recruitment and concomitant rise in ER-mediated transactivation, which was reduced by the addition of RAD001.

CONCLUSION Targeting tumor re-wiring by triple blockade of ERBB, ER and mTORC1 signaling pathways significantly reduces cell proliferation supporting the potential combination in patients who have relapsed on endocrine therapy and retain a functional ER.

Citation Format: Nikitorowicz-Buniak J, Ribas R, Rani A, Pancholi S, Guest SK, Cutler Jr RE, Lalani A, Dowsett M, Johnston SR, Martin L-A. Targeting tumor re-wiring by triple blockade of mTORC1, ERBB and ER signaling pathways in endocrine resistant breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-05-05.

The Familial Cancer Program of the Vermont Cancer Center: Development of a Cancer Genetics Program in a Rural Area

In response to many scientific discoveries linking cancer in certain families to inherited factors, the Vermont Cancer Center established the Familial Cancer Program (FCP) in December 1993. This multifaceted program combines the expertise of clinicians and researchers in many disciplines, including genetics, oncology, psychology, and molecular biology. The program's goals are identification of families in its region with excess cancer, provision of clinical services to such families, and use of research protocols when available and appropriate. This article describes the experience of setting up a familial cancer program in a rural area and discusses both successes and challenges in such an endeavor.

Evidence-based data from animal and human experimental studies on pain relief with antidepressants: a structured review

OBJECTIVE

It has been hypothesized that serotonin reuptake inhibitor antidepressants (ADs) are only weakly antinociceptive but augment noradrenergic (NA) antinociception. Thus, ADs with combined serotonergic (SN) and NA activity, (i.e., the serotonergic/noradrenergic (SN/NA) ADs) should have greater antinociceptive activity versus the NA ADs, which in turn should have more antinociceptive activity than the SN ADs. The objective of this structured review was to test this hypothesis by reviewing relevant basic science literature on the treatment of experimental pain with the above different types of ADs. DESIGN, SETTING, PARTICIPANTS, OUTCOME, MEASURES: Animal or human experimental AD pain treatment studies were located by the usual search methods. For animal studies only placebo-controlled studies were included for review. For human studies only double blind placebo-controlled studies were selected for review. The animal and human studies were then sorted according to the pain model represented, e.g., neuropathic pain model. Studies were then characterized according to the type of AD utilized, and the antinociceptive outcome of the AD trial.

RESULTS

Twenty-two animal studies and 5 human studies fulfilled the inclusion criteria of this structured review. Within the animal nonspecific pain model there were 10 SN/NA AD trials, 9 NA AD trials and 7 SN AD trials. Of these trials 100%, 88.9%, and 14.3% respectfully demonstrated a positive AD antinociceptive effect. Overall, for all the animal models there were 25 SN/NA, 9 NA, and 8 SN trials. Of these trials 92%, 88.9%, and 25% respectfully demonstrated a positive AD antinociceptive effect. For the human pain models, only the SN/NA ADs had been utilized in 7 trials. Here in 42.8% of the trials there was a reported antinociceptive effect.

CONCLUSIONS

Overall, the results of this structured review support the above hypothesis.

Interactive effects of dietary sodium and chloride on the incidence of spontaneous cardiomyopathy (round heart) in turkeys

Two pen trials were conducted in Utah, altitude 1,630 m, with Large White female turkey poults to evaluate effects of dietary Na and chloride (Cl) concentrations on live performance and deaths caused by spontaneous cardiomyopathy (STC, "round heart") from 0 to 35 d of age. A randomized block 2 x 2 factorial arrangement with four replicate pens per treatment was used. Pen size was 3.8 x 5.6 m. In each trial, four starter diets were formulated from a common basal diet (corn-soy-meat) to obtain the following sodium and chloride concentrations: High Na (0.24%):High Cl (0.40%); High Na (0.24%):Low Cl (0.16%); Low Na (0.14%):High Cl (0.40%); and Low Na (0.14%):Low Cl (0.16%). Supplements were NaCl, NaHCO3, NH4Cl, or combinations. After laboratory analysis, true values of Na were slightly lower than expected, Cl was near expected values to slightly low, and K was 1.145%. Body weight and feed conversion ratio at 35 d of age were unaffected in both trials. In both experiments, STC mortality was significantly reduced by the Low Na:High Cl treatment compared to the other treatments. In conclusion, a diet containing 0.10 to 0.12% Na and 0.38 to 0.40% Cl, significantly improved poult livability by reducing STC mortality without adverse effects on poult weight or feed conversion ratio.

Comparison of a picture-sort food-frequency questionnaire with 24-hour dietary recalls in an elderly Utah population

OBJECTIVE

To evaluate the 137-item Utah Picture-sort Food-frequency Questionnaire (FFQ) in the measurement of usual dietary intake in older adults.

DESIGN

The picture-sort FFQ was administered at baseline and again one year later. Three seasonal 24-hour dietary recall interviews were collected during the year between the two FFQs. Mean nutrient intakes were compared between methods and between administrations of the FFQ.

SETTING

The FFQ interviews were administered in respondents' homes or care-centres. The 24-hour diet recalls were conducted by telephone interview on random days of the week.

SUBJECTS

Two-hundred-and-eight men and women aged 55-84 years were recruited by random sample of controls from a case-control study of nutrition and bone health in Utah.

RESULTS

After adjustment for total energy intake, median Spearman rank correlation coefficients between the two picture-sort FFQs were 0.69 for men aged < or = 69 years, 0.66 for men aged > 69 years; and 0.68 for women aged < or = 69 years, 0.67 for women aged > 69 years. Median correlation coefficients between methods were 0.50 for men < or = 69 years old, 0.52 for men > 69 years old; 0.55 for women < or = 69 years old, 0.46 for women > 69 years old.

CONCLUSIONS

We report intake correlations between methods and administrations comparable to those reported in the literature for traditional paper-and-pencil FFQs and one other picture-sort method of FFQ. This dietary assessment method may improve ease and accuracy of response in this and other populations with low literacy levels, poor memory skill, impaired hearing, or poor vision.

International Headache Society headache diagnostic patterns in pain facility patients

OBJECTIVE

Previous studies have indicated that many patients with chronic pain (PWCP) referred to pain facilities for the treatment of neck and/or low back pain complain of associated headaches. The purpose of this study was to characterize the nature of these headaches according to International Headache Society (IHS) headache diagnostic criteria.

DESIGN

In preparation for this study, a questionnaire that reflected IHS headache diagnostic criteria was developed. All consecutive patients admitted to our pain facility complaining of headache completed this questionnaire and received a physical and neurologic examination focused on key aspects of headache. A headache interview was also conducted, using the questionnaire as a question guide. All questionnaires were entered in a computerized database, and IHS diagnoses were arrived at for each patient. As many IHS diagnoses as possible were assigned to each PWCP as long as IHS criteria were fulfilled. In addition, a frequency distribution for headache precipitants and neck-associated symptoms was developed and evaluated by discriminant analysis to determine the diagnostic value of these factors in relation to each IHS diagnostic group.

SETTING

Pain facility (multidisciplinary pain center).

PATIENTS

Consecutive PWCP.

RESULTS

Of 1,466 PWCP, 154 (10.5%) were identified as suffering from severe headache interfering with function. Of these, 55.8% indicated that their headaches were related to an injury for which they were seeking treatment and 83.7% had neck pain. Migraine headache represented the most common diagnostic group (90.3%), with cervicogenic headache representing the second most common (33.8%). Of the total group, 44.2% had more than one headache diagnosis, that is, there was overlap. Cervicogenic headache patients had the greatest percentage of overlap (94.2%), with migraine patients being second (68.3%). The most frequent headache precipitant was mental stress, followed by neck position and activity/exercise. The migraine and cervicogenic headache groups had a statistically significant greater number of neck-associated symptoms when compared with the remaining patients. Of the total headache group, 74.6% complained that they had a tender point at the back of their neck. Cervicogenic, migraine, and tension PWCP had the greatest frequency of head or neck tender points. The discriminant analysis for neck-associated symptoms yielded the following symptoms as the most common predictors of headache across IHS diagnostic groups: clues to onset were severe headache beginning at the neck or tender point and numbness in arms and legs; headache brought on by neck position and arms overhead; and neck symptoms consisting of a tender point in the neck and feeling severe headache in the neck.

CONCLUSIONS

Headache can and should be considered a frequent comorbid condition in PWCP. Because of the overlap data, more precise diagnostic criteria may be required to separate cervicogenic headache from migraine headache. Neck-associated symptoms seem to be important even to those PWCP diagnosed with migraine headache.

Regulation of PKC delta expression by estrogen and rat placental lactogen-1 in luteinized rat ovarian granulosa cells

Protein kinase C (PKC) delta is dramatically upregulated in the corpus luteum in the second half of pregnancy in the rat. To gain insight into the hormonal regulation of PKC delta expression, studies were undertaken to analyze the regulation of PKC delta expression in a luteinized rat granulosa cell model. PKC delta protein expression was evaluated in luteinized granulosa cells, isolated from human (h)CG-treated immature female rats 7 h after the injection of an ovulatory dose of hCG and cultured up to 12 days. Cytochrome P450 cholesterol side chain cleavage enzyme expression was observed throughout the culture period, and a majority of the cells expressed steroidogenic acute regulatory protein and responded to rat placental lactogen (rPL)-1 by exhibiting hypertrophy, consistent with maintenance of the luteal phenotype. Both PKC delta protein and mRNA expression increased 3.5-4-fold with time of culture, and PKC delta mRNA expression could be eliminated by treatment of cells with the PKC inhibitor GF109203X. E(2) caused a specific dose- and time-dependent increase in expression of PKC delta protein of twofold, whereas PKC delta mRNA was unaffected by E(2) over a 12-day culture period. Treatment of cells with 500 ng/ml rPL-1 for the final 4 days of a 12-day culture in the absence of E(2) had no effect on PKC delta protein or mRNA expression, while treatment with 500 or 3000 ng/ml rPL-1 in the presence of E(2) significantly enhanced both PKC delta protein and mRNA expression (up to threefold). These results show that two of the major regulators of luteal function in the second half of pregnancy in the rat, E(2) and rPL-1, cooperate to regulate PKC delta expression in luteinized granulosa cells.

Chronic pain disability exaggeration/malingering and submaximal effort research

OBJECTIVE

This is the first review of chronic pain (CP) malingering/disease simulation research. The purpose of this review was to determine the prevalence of malingering within CP patients (CPPs), whether evidence exists that malingering can be detected within CPPs, and to suggest some avenues of research for this topic.

DESIGN

A computer and manual literature search produced 328 references related to malingering, disease simulation, dissimulation, symptom magnification syndrome, and submaximal effort. Of these, 68 related to one of these topics and to pain. The references were reviewed in detail, sorted into 12 topic areas, and placed into tabular form. These 12 topic areas addressed the following: existence of malingering within the CP setting; dissimulation, identification simulated (faked) facial expressions of pain; identification of malingering by questionnaire; identification of malingered sensory impairment; identification of malingered loss of hand grip strength; identification of submaximal effort by isometric strength testing; identification of submaximal or malingered effort by isokinetic strength testing; identification of submaximal or malingered effort by the method of coefficient of variation; self-deception; symptom magnification syndrome; and miscellaneous malingering identification studies. Each report, in each topic area, was rated for scientific quality according to guidelines developed by the Agency for Health Care, Policy and Research (AHCPR) for rating the level of evidence presented in the reviewed study. The AHCPR guidelines were then used to rate the strength and consistency of the research evidence in each topic area based on the type of evidence the reports represented. All review conclusions were based on the results of these ratings.

SETTING

Any medical setting reporting on either malingering or disease simulation, or dissimulation, or submaximal effort and pain.

PATIENTS

Normal volunteers, CPPs, or any group asked to produce a submaximal or malingered effort or a malingered test profile.

RESULTS

The reviewed studies indicated that malingering and dissimulation do occur within the CP setting. Malingering may be present in 1.25-10.4% of CPPs. However, because of poor study quality, these prevalence percentages are not reliable. The study evidence also indicated that malingering cannot be reliably identified by facial expression testing, questionnaire, sensory testing, or clinical examination. There was no acceptable scientific information on symptom magnification syndrome. Hand grip testing using the Jamar dynamometer and other types of isometric strength testing did not reliably discriminate between a submaximal/malingering effort and a maximal/best effort. However, isokinetic strength testing appeared to have potential for discriminating between maximal and submaximal effort and between best and malingered efforts. Repetitive testing with the coefficient of variation was not a reliable method for discriminating a real/best effort from a malingered effort.

CONCLUSIONS

Current data on the prevalence of malingering within CPPs is not consistent, and no conclusions can be drawn from these data. As yet, there is no reliable method for detecting malingering within CPPs, although isokinetic testing shows promise. Claims by professionals that such a determination can be made should be viewed with caution.

Identification of cAMP-dependent protein kinase holoenzymes in preantral- and preovulatory-follicle-enriched ovaries, and their association with A-kinase-anchoring proteins

Undifferentiated cells from preantral (PA) follicles respond to high levels of cAMP in a different manner than do differentiated cells from preovulatory (PO) follicles. We hypothesized that this differential response of PA and PO cells to cAMP could be due, in part, to either a difference in the profile of isoforms that comprise the cAMP-dependent protein kinase (PKA) holoenzymes and/or a difference in the interaction of PKA with A-kinase-anchoring proteins (AKAPs). To test these hypotheses, PKA activity, PKA holoenzymes, PKA subunits and AKAPs from PA and PO ovaries were compared. Soluble PKA holoenzymes and regulatory (R) subunits were separated by DEAE-cellulose chromatography and sucrose-density-gradient centrifugation. PKA R subunits were distinguished by photoaffinity labelling, autophosphorylation, size, isoelectric point and immunoreactivity. AKAPs were identified by RII subunit overlay assays and immunoreactivity. The results showed that extracts from PA and PO ovaries exhibited equivalent PKA holoenzyme profiles and activities, characterized by low levels of PKA type I (PKAI) holoenzyme and two distinct PKAII holoenzyme peaks, one containing only RIIbeta subunits (PKAIIbeta) and one containing both PKAIIbeta and PKAIIalpha holoenzymes. Both PA and PO ovarian extracts also contained PKA catalytic (C)-subunit-free RIalpha, while only PO ovaries exhibited C-subunit-free RIIbeta. Consistent with the elevated levels of C-subunit-free RIIbeta in PO cells, PKA activation in PO cells required higher concentrations of forskolin than that in PA cells. While extracts of PA and PO ovaries exhibited a number of similar AKAPs, including four prominent ones reactive with anti-AKAP-KL antisera (where AKAP-KL is an AKAP especially abundant in kidney and liver), cAMP-agarose affinity chromatography revealed two major differences in AKAP binding to purified R subunits. PO ovaries contained increased levels of AKAP80 (AKAP of 80 kDa) bound selectively to R subunits in DEAE-cellulose peak 2 (comprising PKAIIbeta and RIalpha), but not to R subunits in DEAE-cellulose peak 3 (comprising PKAIIalpha, PKAIIbeta and RIIbeta). PO ovaries also showed increased binding of R subunits to AKAPs reactive with anti-AKAP-KL antisera at 210, 175, 150 and 115 kDa. Thus in PO ovaries, unlike in PA ovaries, the majority of AKAPs are bound to R subunits. These results suggest that altered PKA-AKAP interactions may contribute to the distinct responses of PA and PO follicles to high levels of cAMP, and that higher cAMP levels are required to activate PKA in PO ovaries.

Regulation of protein kinase C delta by estrogen in the MCF-7 human breast cancer cell line

We have previously shown that estrogen up-regulates expression of protein kinase C (PKC) delta in the rat and rabbit corpus luteum as well as in luteinized rat granulosa primary cell cultures. To determine whether a similar regulation of the PKC delta isoform by estrogen occurred in another estrogen responsive system, we investigated the estrogen receptor positive MCF-7 human breast cancer cells. In a characterization of PKC isoforms in MCF-7 cells we determined that PKC delta was the predominant PKC isoform. However in contrast to the effect of estrogen on PKC delta expression in ovarian cells, estrogen treatment of MCF-7 cells resulted in a significant decrease in PKC delta protein and mRNA expression in a time and dose dependent manner. Treatment of MCF-7 cells with 10(-10)-10(-8) M estrogen for 7 days down-regulated specifically PKC delta mRNA and protein while expression of other PKC isoforms was unchanged. The opposite regulation of PKC delta expression in ovarian and breast cancer cells prompted us to evaluate the type of estrogen receptor present in both cell types. Results showed that luteinized rat granulosa cells expressed predominantly estrogen receptor beta while the MCF-7 cells expressed predominantly estrogen receptor alpha and barely detectable levels of estrogen receptor beta. These results suggest that the differential ability of estrogen to regulate PKC beta expression could potentially be a result of differential signaling through the two estrogen receptor subtypes.

Breath ethane as a marker of reactive oxygen species during manipulation of diet and oxygen tension in rats

Breath ethane, O2 consumption, and CO2 production were analyzed in 24-mo-old female Fischer 344 rats that had been fed continuously ad libitum (AL) or restricted 30% of AL level (DR) diets since 6 wk of age. Rats were placed in a glass chamber that was first flushed with air, then with a gas mixture containing 12% O2. After equilibration, a sample of the outflow was collected in gas sampling bags for subsequent analyses of ethane and CO2. The O2 and CO2 levels were also directly monitored in the outflow of the chamber. O2 consumption and CO2 production increased for DR rats. Hypoxia decreased O2 consumption and CO2 production for the AL-fed and DR rats. These changes reflect changes in metabolic rate due to diet and PO2. A significant decrease in ethane generation was found in DR rats compared with AL-fed rats. Under normoxic conditions, breath ethane decreased from 2.20 to 1.61 pmol ethane/ml CO2. During hypoxia the levels of ethane generation increased, resulting in a DR-associated decrease in ethane from 2.60 to 1.90 pmol ethane/ml CO2. These results support the hypothesis that DR reduces the level of oxidative stress.

Identification of residues in the cysteine-rich domain of Raf-1 that control Ras binding and Raf-1 activity

We have identified mutations in Raf-1 that increase binding to Ras. The mutations were identified making use of three mutant forms of Ras that have reduced Raf-1 binding (Winkler, D. G., Johnson, J. C., Cooper, J. A., and Vojtek, A. B. (1997) J. Biol. Chem. 272, 24402-24409). One mutation in Raf-1, N64L, suppresses the Ras mutant R41Q but not other Ras mutants, suggesting that this mutation structurally complements the Ras R41Q mutation. Missense substitutions of residues 143 and 144 in the Raf-1 cysteine-rich domain were isolated multiple times. These Raf-1 mutants, R143Q, R143W, and K144E, were general suppressors of three different Ras mutants and had increased interaction with non-mutant Ras. Each was slightly activated relative to wild-type Raf-1 in a transformation assay. In addition, two mutants, R143W and K144E, were active when tested for induction of germinal vesicle breakdown in Xenopus oocytes. Interestingly, all three cysteine-rich domain mutations reduced the ability of the Raf-1 N-terminal regulatory region to inhibit Xenopus oocyte germinal vesicle breakdown induced by the C-terminal catalytic region of Raf-1. We propose that a direct or indirect regulatory interaction between the N- and C-terminal regions of Raf-1 is reduced by the R143W, R143Q, and K144E mutations, thereby increasing access to the Ras-binding regions of Raf-1 and increasing Raf-1 activity.

Autoregulation of the Raf-1 serine/threonine kinase

The Raf-1 serine/threonine kinase is a key protein involved in the transmission of many growth and developmental signals. In this report, we show that autoinhibition mediated by the noncatalytic, N-terminal regulatory region of Raf-1 is an important mechanism regulating Raf-1 function. The inhibition of the regulatory region occurs, at least in part, through binding interactions involving the cysteine-rich domain. Events that disrupt this autoinhibition, such as mutation of the cysteine-rich domain or a mutation mimicking an activating phosphorylation event (Y340D), alleviate the repression of the regulatory region and increase Raf-1 activity. Based on the striking similarites between the autoregulation of the serine/threonine kinases protein kinase C, Byr2, and Raf-1, we propose that relief of autorepression and activation at the plasma membrane is an evolutionarily conserved mechanism of kinase regulation.

Heat-shock protein-25/27 phosphorylation by the delta isoform of protein kinase C

Small heat-shock proteins (sHSPs) are widely expressed 25-28 kDa proteins whose functions are dynamically regulated by phosphorylation. While recent efforts have clearly delineated a stress-responsive p38 mitogen-activated protein-kinase (MAPK)-dependent kinase pathway culminating in activation of the heat-shock (HSP)-kinases, mitogen-activated protein-kinase-activated protein kinase-2 and -3, not all sHSP phosphorylation events can be explained by the p38 MAPK-dependent pathway. The contribution of protein kinase C (PKC) to sHSP phosphorylation was suggested by early studies but later questioned on the basis of the reported poor ability of purified PKC to phosphorylate sHSP in vitro. The current study re-evaluates the role of PKC in sHSP phosphorylation in the light of the isoform complexity of the PKC family. We evaluated the sHSP phosphorylation status in rat corpora lutea obtained from two stages of pregnancy, mid-pregnancy and late-pregnancy, which express different levels of the novel PKC isoform, PKC-delta. Two-dimensional Western blot analysis showed that HSP-27 was more highly phosphorylated in vivo in corpora lutea of late pregnancy, corresponding to the developmental stage in which PKC-delta is abundant and active. Late-pregnant luteal extracts contained a lipid-sensitive HSP-kinase activity which exactly co-purified with PKC-delta using hydroxyapatite and S-Sepharose column chromatography. To determine whether there might be preferential phosphorylation of sHSP by a particular PKC isoform, purified recombinant PKC isoforms corresponding to those PKC isoforms detected in rat corpora lutea were evaluated for HSP-kinase activity in vitro. Recombinant PKC-delta effectively catalysed the phosphorylation of sHSP in vitro, and PKC-alpha was 30-50% as effective as an HSP-kinase; other PKCs tested (beta1, beta2, epsilon and zeta) were poor HSP-kinases. These results show that select PKC family members can function as direct HSP-kinases in vitro. Moreover, the observation of enhanced luteal HSP-27 phosphorylation in vivo, in late pregnancy, when PKC-delta is abundant and active, suggests that select PKC family members contribute to sHSP phosphorylation events in vivo.

Racial differences in the renal response to blood pressure lowering during chronic angiotensin-converting enzyme inhibition: a prospective double-blind randomized comparison of fosinopril and lisinopril in older hypertensive patients with chronic renal insufficiency

This study was undertaken to compare the effects of chronic angiotensin-converting enzyme (ACE) inhibition on blood pressure (BP) and renal hemodynamics in older black and nonblack hypertensive patients with chronic renal insufficiency. A multicenter, placebo lead-in double-blind, parallel group study was performed to compare the antihypertensive efficacy and renal hemodynamic response to the once-daily ACE inhibitor fosinopril (n = 14) and lisinopril (n = 13) over a 22-week period. The study goal was to lower diastolic blood pressure (DBP) to 90 mm Hg or less. Furosemide was added after 6 weeks if blood pressure goal was not achieved. At outpatient clinics at university medical centers, 27 older hypertensive patients (> or = 45 years; 12 blacks, 15 nonblacks; 19 male, eight female) with DBP of 95 mm Hg or higher and 4-hour creatinine clearance 20 to 70 mL/min/1.73 m2 were studied. Changes (delta) from baseline in BP, glomerular filtration rate (GFR), and renal plasma flow (RPF) were measured. Mean systolic blood pressure (SBP) and DBP decreased significantly and to a similar extent in randomized groups: fosinopril (mean +/- SEM) delta DBP at 6 weeks was -13 +/- 2 (P < 0.0001; 95% CI, -16 to -9) and at 22 weeks was -12 +/- 2 (P < 0.0001; 95% CI, -16 to -9); lisinopril delta DBP at 6 weeks was -14 +/- 6 (P < 0.0001; 95% CI, -10 to -18) and at 22 weeks was -16 +/- 2 (P < 0.0001; 95% CI, -12 to -21). GFR and RPF did not change significantly in either group. BP was significantly reduced and to a similar extent in blacks and nonblacks: for blacks, delta DBP at 6 weeks was -11 +/- 3 (P < 0.05; 95% CI, -0.01 to -9) and at 22 weeks was -16 +/- 2 (P < 0.0001; 95% CI, -11 to -20); for nonblacks, delta DBP at 6 weeks was -14 +/- 1 (P < 0.0001; 95% CI, -12 to -17) and at 22 weeks was -12 +/- 2 (P < 0.0001; 95% CI, -16 to -8). Eight patients (five blacks and three nonblacks) required an addition of furosemide after 6 weeks to reach the DBP goal of < or = 90 mm Hg at 22 weeks. GFR was not significantly altered for either racial group at 6 weeks; however, at 22 weeks; however, at 22 weeks, GFR decreased significantly in blacks (delta GFR, -16 +/- 5; P < 0.006; 95% CI, -26 to -5) and tended to increase in nonblacks (delta GFR, 7 +/- 6; P > 0.25). delta GFR correlated directly with the delta RPF (delta GFR = 0.0611* delta RPF -2.35 +; r = 0.68; P < 0.003). There was no correlation between delta MAP and delta GFR or delta RPF in blacks or nonblacks. We conclude that chronic ACE inhibition with fosinopril and lisinopril alone or in combination with furosemide lowers BP in older blacks and nonblacks with hypertension and chronic renal insufficiency. Racial differences in the renal hemodynamic response to chronic ACE inhibition were noted and appear to be independent of diuretic use and the magnitude of BP lowering.

Chronic pain-associated depression: antecedent or consequence of chronic pain? A review

OBJECTIVE

To determine the current status for the association of chronic pain and depression and to review the evidence for whether depression is an antecedent or consequence of chronic pain (CP).

DESIGN

A computer and manual literature review yielded 191 studies that related to the pain-depression association. These reports were reviewed and sorted into seven categories relating to the topic of this paper. Eighty-three studies were then selected according to inclusion criteria and subjected to a structured review.

SETTING

Any medical treatment setting including pain treatment as inclusion criteria for selection of studies.

PATIENTS

Any patients with any type of chronic pain.

RESULTS

The reviewed studies were consistent in indicating that there is a statistical relationship between chronic pain and depression. For the relationship between pain and depression, there was greater support for the consequence and scar hypotheses than the antecedent hypothesis.

CONCLUSIONS

Depression is more common in chronic pain patients (CPPs) than in healthy controls as a consequence of the presence of CP. At pain onset, predisposition to depression (the scar hypothesis) may increase the likelihood for the development of depression in some CPPS. Because of difficulties in measuring depression in the presence of CP, the reviewed studies should be interpreted with caution.

Mammalian Raf-1 is activated by mutations that restore Raf signaling in Drosophila

An interaction with the Ras proto-oncogene product is a requirement for Raf-1 activation in many signaling cascades. The significance of this interaction is demonstrated by the fact that a mutation preventing the Ras-Raf interaction severely impairs the function of both mammalian (Raf-1) and Drosophila (D-Raf) Raf proteins. In D-Raf, however, dominant intragenic mutations have been identified that suppress the effect of the Ras-binding site (RBS) mutation. To address the mechanism by which these mutations restore Raf signaling, we have introduced the suppressor mutations into the analogous residues of mammalian Raf-1. Here, we show that rather than compensating for the RBS mutation by restoring the Ras-Raf-1 interaction, the suppressor mutations increase the enzymatic and biological activity of Raf-1, allowing Raf-1 to signal in the absence of Ras binding. Surprisingly, we find that while one of the suppressor mutations (P181L) increases the basal kinase activity of Raf-1, it also abolishes the ability of wild-type Raf-1 to become activated by Ras. This mutation occurs in the cysteine-rich domain (CRD) of Raf-1 and demonstrates the importance of this region for a productive Ras-Raf interaction. Finally, we present evidence that the most activating suppressor mutation (G498S) increases Raf-1 activity by introducing a novel phosphorylation site into the L12 activation loop of the Raf-1 kinase domain.

The complexity of Raf-1 regulation

The activation of the serine/threonine kinase Raf-1 is proving to be an intricate multistep process. Recent advances in elucidating how Raf-1 becomes activated in response to signaling events have emphasized the role of phosphorylation and protein interactions in Raf-1 regulation. The picture clearly emerging is that Raf-1 activity can be regulated by multiple mechanisms.

Transcutaneous electrical nerve stimulation (TENS) treatment outcome in long-term users

OBJECTIVE

Previous reviewers of the literature on transcutaneous electrical nerve stimulation (TENS) outcome have concluded the following: (a) there are few long-term TENS follow-up studies, and (b) fewer studies have addressed the effect of long-term TENS use on outcome variables other than pain (e.g., function). DESIGN/SETTING/PARTICIPANTS/OUTCOME MEASURES: From a population of 2,003 chronic pain patients (CPPs) who bought a TENS device for pain management, 506 patients were randomly selected and interviewed by telephone long enough after purchase to allow at least 6 months of TENS use. The interview process used a structured "skip" questionnaire designed to assess the CPPs' perceptions regarding the effectiveness of TENS for a variety of outcome variables. Of the 506 CPPs interviewed, 376 (74.3%) had used their TENS device for 6 months or longer and were defined as long-term users. The responses of this group of CPPs to the telephone questionnaire were then subjected to statistical analysis.

RESULTS

Paired t-tests, correlated z-tests, SS Wilks, and chi-square tests demonstrated statistically significant change or improvement (p < 0.05) that paralleled the introduction of TENS use in the following outcome variables: less pain interference with work, home, and social activities; increased activity level and pain management; decreased use of other therapies (e.g., physical therapy, occupational therapy, chiropractic); decreased use of narcotics, tranquilizers, muscle relaxants, nonsteroidal anti-inflammatory drugs and steroids.

CONCLUSIONS

The results suggest that TENS is associated with improvement on multiple outcome variables in addition to pain relief for CPPs who are long-term users. Also, for some CPPs, long-term TENS use continues to be effective.

Human plasma concentrations of R, S, and racemic flurbiprofen given as a toothpaste

Flurbiprofen, an arylpropionic acid (APA) class nonsteroidal antiinflammatory drug (NSAID), is commercially available only as the racemic mixture, although its pharmacologic effect has been credited primarily to the S isomer. In humans, the bioavailability of racemic flurbiprofen absorbed from the oral cavity has been studied measuring the total concentration of S- and R-flurbiprofen, and the pharmacokinetics of S- and R-flurbiprofen have been studied after oral administration of racemic flurbiprofen. In this study, the plasma concentrations of S-flurbiprofen and to some extent R-flurbiprofen were studied after brushing with a toothpaste containing different mixtures of S- and R-flurbiprofen. The toothpaste formulations contained 1% racemic (50:50), eutectic (14:86), 1%, 0.5%, and 0.25% (5:95) R- to S-flurbiprofen. Both S- and R-flurbiprofen were rapidly absorbed, with a time to reach maximum concentration (tmax) of 1.2 to 1.4 hours. Based on the AUC, the amount of S-flurbiprofen absorbed increased proportionally when given as the 0.25% (5:95) preparation to the 0.5% (5:95) mixture but did not increase significantly above the 0.5% (5:95) mixture when given as 1% (5:95) R- to S-flurbiprofen. This suggests that dose-proportional absorption of S-flurbiprofen is not maintained at higher concentrations. The elimination of S-flurbiprofen appears to be variable and prolonged after this mode of administration, as observed from plasma concentrations. Further controlled and more prolonged studies of S- and R-flurbiprofen are needed to confirm these observations.

Age differences in sensitivity to H2O2- or NO-induced reductions in K(+)-evoked dopamine release from superfused striatal slices: reversals by PBN or Trolox

Previous research has indicated that many age-related functional alterations may be the result of a decreased ability of the organism to respond to oxidative stress (OS). However, this hypothesis is based on indirect indices of function (e.g., increased vulnerability of hepatocytes from senescent animals to H2O2-induced DNA damage, increases in lipofuscin accumulation). More direct tests of this hypothesis, especially as it relates to brain aging, have not been extensively undertaken. Present experiments were carried out to make such tests by examining age differences in the sensitivity to OS on reductions in striatal dopamine (DA) release. Thus, K(+)-evoked DA (K(+)-ERDA) release from superfused striatal slices from young (6-8 month) and old (24-25 month) animals was examined following either: (a) application of the NO-generator sodium nitroprusside or (b) preincubation with H2O2. In order to assess the specific effects of OS on muscarinic (mAChR) sensitivity, oxotremorine-enhancement of K(+) -ERDA was examined following incubation with H2O2. Results showed that the striatal tissue from the old animals showed greater sensitivity to both H2O2 and NO than young animals, and stimulated DA decreased at lower concentrations of these agents (e.g., NO--100 microM young, 30 microM old). In addition, H2O2 was also effective in reducing oxo-enhanced K(+)-ERDA and was more effective as a function of age. If the striatal tissue was incubated in either Trolox (alpha-tocopherol) or alpha-phenyl-n-tert-butyl nitrone (PBN) prior to OS, the negative effects of NO. and H2O2 were reversed in both age groups. Results are discussed in terms of age-related membrane and endogenous antioxidant alterations that could induce increases in sensitivity to OS and the specificity of antioxidants in reducing this sensitivity in key functional systems.

Physician limitations when assessing work capacity: a review

Literature evidence indicates that physicians have great difficulty in translating medical impairment into functional limitation and thereby establishing the work capacity or the residual functional capacity (RFC) of the injured worker. This is especially true for the chronic pain patient (CPP). Development of quantitative methods for the measurement of functional capacity (FC), have not improved the problems involved in the measurement of RFC and the translation of RFC into the demand minimum functional capacity (DMFC) of some job or jobs. The relationship between FC, RFC, work capacity and DMFC is reviewed. We have developed a method/battery for measuring RFC in CPPs utilizing the Dictionary of Occupational Titles (DOT) which is readily translatable into DMFC of some job or jobs. Suggestions are made for future directions in the measurement of work capacity.

Area specific alterations in muscarinic stimulated low Km GTPase activity in aging and Alzheimer's disease: implications for altered signal transduction

Carbachol-stimulated low Km GTPase activity (an index of muscarinic receptor-G protein coupling) was examined in hippocampus, basal ganglia, orbital frontal gyrus and superior frontal gyrus obtained from mature, aged and Alzheimer's Disease (AD) groups. Results indicated that carbachol-stimulated low Km GTPase activities in basal ganglia were as follows: mature controls > aged > AD, and there was a trend toward a similar pattern of decline in the hippocampus. No differences were seen in the two cortical areas examined; however, carbachol-stimulated low Km GTPase activity was small in the mature controls. Importantly, there were significant negative correlations between disease duration and carbachol-stimulated low Km GTPase activity in all areas examined except the orbital frontal gyrus. The longer the duration of the disease the lower the carbachol-stimulated low Km GTPase activity. Results suggest that age and disease-related changes in mAChR-G protein interactions in the basal ganglia may contribute to reduced signal transduction (ST). In addition, since decreased carbachol-stimulated low Km GTPase activity has also been observed in the aged rat; thus, investigations of the factors involved in decrements in signal transduction in the aged rat may be useful for understanding these alterations in aged humans or victims of AD.

Delta protein kinase-C in the rat ovary: estrogen regulation and localization

The present studies were undertaken to examine the cellular distribution and regulation of delta protein kinase-C (PKC) at different stages of luteal differentiation in the rat. Results from in situ hybridization studies with a delta PKC-specific probe demonstrated that delta PKC was localized specifically in granulosa cells of healthy preantral, small antral, and preovulatory follicles and corpora lutea from the second half of pregnancy. Northern and Western blot analyses showed that levels of delta PKC protein and messenger RNA were elevated 25- and 35-fold, respectively, in the second half of pregnancy over levels in preovulatory follicle-enriched ovaries, peaking between days 18-20 of pregnancy. Levels of alpha PKC, beta PKC, and zeta PKC remained unchanged during luteal differentiation. In rats hypophysectomized and hysterectomized on day 12 of pregnancy and in immature rats containing corpora lutea induced with PMSG followed by hCG injections, exogenous estrogen caused 3- and 7-fold increases in delta PKC protein, respectively. In the immature rat model, delta PKC messenger RNA levels were not altered by exogenous estrogen. Although exogenous testosterone also elevated delta PKC protein levels, exogenous dihydrotestosterone and progesterone were ineffective. These results suggest that estrogen may participate, at a posttranscriptional level, in the dramatic induction of delta PKC seen at the end of pregnancy in rat corpora lutea.

Functional electrical stimulation treatment of postradiculopathy associated muscle weakness

Eighteen chronic pain patients (CPPs) with postradiculopathy-associated muscle weakness were entered into a nonrandomized functional electrical stimulation (FES) clinical treatment study to determine if FES can improve postradiculopathy associated muscle weakness. Because of the clinical nature of the unit, the CPPs could not be denied treatments other than FES. To control for these other treatments, the CPPs were used as their own controls with two control conditions, ie, where possible, the contralateral probable normal muscle was used as a control (control 1) and; in a subgroup of CPPs (n = 6), FES treatment was initially withheld to the probable weak muscle (control 2). Strength was measured as isometric maximum voluntary contraction (IMVC) and was used as the outcome treatment variable. IMVC was measured in both the probable weak and contralateral probable normal muscles at entrance into the Pain Center, at beginning of FES treatment, at completion of FES treatment, and for the control 2 condition at the end of the non-FES treatment period. Statistical analyses of the IMVC strength results using the two control conditions indicated (1) both the FES-treated and untreated muscles increased significantly in IMVC strength, (2) improvement in IMVC strength for FES-treated muscles was significantly greater than for probable normal FES-untreated muscles and, (3) improvement in IMVC strength in FES-treated muscles was significantly greater during the FES-treatment period than during the non-FES treatment period. FES treatment of postradiculopathy-associated muscle weakness in CPPs seems to increase the strength of the probable weak muscle above the increase in strength provided by other concurrent treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring residual functional capacity in chronic low back pain patients based on the Dictionary of Occupational Titles

STUDY DESIGN

This study designed and tested a functional battery based on the Dictionary of Occupational Titles (DOT).

OBJECTIVES

Such a battery can be used to measure residual functional capacity (RFC) in chronic pain patients (CPP) and results can be matched against the demand minimum functional capacities (DMFC) of DOT jobs.

SUMMARY OF BACKGROUND DATA

Physicians have difficulty translating medical impairment into functional limitation and thereby establishing the RFC of CPPs.

METHODS

The DOT, a USA government publication, provides information about physical demands of every USA job according to 36 factors and subfactors. The authors defined and developed a functional battery based on these factors/subfactors. This battery was tested on 67 consecutive CPPs to determine the percentage of CPPs able to pass specific job factors and the full battery and return to some DOT job, and evaluated the effects of pain on battery performance. The data were factor analyzed.

RESULTS

The battery determined if CPPs could perform DOT job factors and had the necessary RFC to be placed in a DOT job. The vast majority of CPPs could not pass the full battery and the presence of pain and original job classification predicted whether a CPP could perform a job factor. Factor analyses grouped the factors into four independent categories supporting the design of the battery.

CONCLUSION

The battery can assess whether CPPs are able to return to work.

Regulation of delta protein kinase C during rat ovarian differentiation

Studies were undertaken to classify protein kinase C (PKC) forms present in rat corpora lutea and to begin to evaluate their regulation during ovarian differentiation. Hydroxyapatite (HAP) column chromatography of rat luteal tissue revealed the presence of multiple forms of PKC (alpha, beta, delta, zeta). Identification of the PKC isoforms was based upon elution positions from HAP column chromatography and immunoreactivity. The delta PKC isoform was identified as the major Ca(2+)-independent form of PKC present in rat luteal tissue. The Ca(2+)-independent, lipid-dependent phosphorylation of the 80-kDa delta PKC was readily detectable in soluble luteal extracts and was shown to reflect autophosphorylation of delta PKC. To evaluate the regulation of PKC isoforms during ovarian differentiation, PKC protein levels were compared between preovulatory follicle-enriched ovaries and corpora lutea obtained on day 16 of pregnancy. Levels of delta PKC protein were greatly elevated in corpora lutea compared to levels in preovulatory follicles. In contrast, levels of alpha and beta PKC protein remained constant while levels of zeta PKC were slightly higher in the follicular than the luteal extract. Levels of delta PKC mRNA were also higher in corpora lutea than in preovulatory follicles. These results are the first to demonstrate the physiological regulation of delta PKC with follicular differentiation into corpora lutea and implicate a role for this prominent PKC form in the corpus luteum during pregnancy.

Changes in G protein-mediated signal transduction in aging and Alzheimer's disease

Previous reports have shown that there are age-related reductions in muscarinic receptor (mAChR) sensitivity to agonist stimulation. Our research has elucidated the mechanisms involved in this loss. These studies have shown that this decline is the result of decreases in mAChR concentration, reductions in the number of neuronal cells, and altered phosphoinositide (PI)-mediated signal transduction (ST). The decrements in PI-mediated ST are observed as a reduced ability of muscarinic (m) agonists to enhance K(+)-evoked release of DA (K+ ERDA) from striatal slices from old rats. Additional experiments indicated that the locus of the ST deficits appears to be at the mAChR-G protein interface, since attempts to bypass this interface reduced m-enhanced K+ ERDA deficits in the striata from old rats. Moreover, it appears that the ability of mAChR to decouple from their respective G proteins is reduced as a function of age, since carbachol-stimulated low KM GTPase activity was found to be reduced in hippocampal and striatal tissue obtained from old rats. Similar findings were observed in this parameter in AD hippocampus and basal ganglia. Further reductions were seen in carbachol-stimulated low KM GTPase as a function of the duration of the disease. Results are discussed in terms of structural membrane alterations in aging and disease that may lead to reductions in the efficacy of receptor-G protein coupling/uncoupling.

Functional capacity and residual functional capacity and their utility in measuring work capacity

OBJECTIVE

The pain physician is often asked to establish the medical impairment of the chronic pain patient (CPP) and from that determination ascertain the work capacity of the CPP. Functional capacity (FC) testing has recently been introduced as a more objective and accurate way of facilitating the determination of work capacity. However, there are conceptual problems with the measurement of FC. These will be reviewed and the relationship of FC to residual functional capacity (RFC) will be determined. Finally, a method for measuring RFC in a job-specific manner will be suggested.

DATA SOURCES

The literature in reference to the measurement of medical impairment, FC, and RFC was reviewed.

STUDY SELECTION

Studies appropriate to the objective of this review were selected for inclusion.

CONCLUSIONS

The FC and RFC are poorly defined. Lack of definition has interfered with design of appropriate test batteries specific to work capacity. To circumvent this problem a job-specific RFC measurement method is suggested. This method is based on the Dictionary of Occupational Titles.

Periodontal screening and recording: perceptions and effects on practice

Despite recent clinical innovations, there are considerable periodontal treatment needs for the general population. This study shows that dentists believe the new periodontal screening method will be useful in determining and providing treatment needs.

Opiate detoxification protocols. A clinical manual

The purpose of any opiate detoxification protocol is to minimize or eliminate the signs and symptoms associated with opiate withdrawal, thereby decreasing the chances of relapse to opiate dependence. In the last few years, because of the development of new medications such as clonidine, for the treatment of opiate withdrawal, a number of new protocols have been developed. Four different types of protocols are reviewed and outlined: methadone substitution/detoxification, codeine or other opiate substitution/detoxification, opiate of choice detoxification, and buprenorphine substitution/detoxification. In addition, six protocols utilizing clonidine are presented, including a protocol utilizing opiate antagonist precipitated withdrawal. Finally, two protocols that utilize naltrexone are outlined, and adjunct medications potentially useful in opiate detoxification are reviewed. Some suggestions for the treatment of drug-seeking behavior during detoxification and the advantages and disadvantages of the various protocols are summarized.

The prediction of return to the workplace after Multidisciplinary Pain Center treatment

The prediction of return to the workplace after Multidisciplinary Pain Center (MPC) treatment has become a major research area. To delineate the variables that predict this outcome, the authors reviewed 164 multidisciplinary variables studies. Of these, 79 addressed work as an outcome variable. Twenty-six studies attempted to identify patient variables predicting return to the workplace. These latter studies were critically inspected for eight methodological criteria: pain location, follow-up time interval, response percentage and follow-up method, return to work subcategorization, vocational movement, univariate vs. multivariate statistics, multi-colinearity and variance, and statistical treatment of dropouts. In addition, other disability studies besides those in the chronic pain area were reviewed for return to the workplace predictor variables. Of these 26 studies, only a few appeared to satisfy the criteria examined. In addition, many studies were in conflict with one another on whether a variable was predictive. The review of the nonchronic pain/disability prediction literature yielded a large number of potential predictors that related to the work area. It is unclear which variables or set of variables predict return to the workplace after MPC treatment. Chronic pain studies may be neglecting the work area as an important source of return to the workplace predictor variables.

The effects of aging on muscarinic receptor/G-protein coupling in the rat hippocampus and striatum

In the striatum and hippocampus, there is a loss of sensitivity to muscarinic agonists with age which has been traced to events early in the signal transduction pathway. Our laboratory has therefore focussed on investigations at this level. The current experiments investigate the effects of age on G-protein/receptor interactions by using competitive binding assays to measure the ability of GppNHp to decrease the proportion of receptors bound to G-proteins in the absence and the presence of added Mg2+. L-[3H]Quinuclidinyl benzilate was used as a nonselective ligand and [3H]pirenzepine as an M1 selective ligand. We find that: (1) muscarinic receptors and G-proteins in the striatum appear to become loosely coupled with age, with no change in Mg2+ sensitivity. (2) M1-receptor/G-protein complexes in the hippocampus display increased sensitivity to the presence of Mg2+ with age, with those from old but not young tissue requiring added Mg2+ in order to uncouple. This effect, however, may not be M1 specific.