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Abstract PD3-14: Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer
Forero, Andres , Mita, Monica , Miller, KD, Weise, Amy, Krop, Ian E. , Burris, Howard A. , Tsai, Meng‐Chen , Liu, MC, Hurvitz, SA, Wilks, Sharon , Diab, Sami, Han, HS, Nanda, Rita , O’Shaughnessy, J., Modi, Shanu , Pusztai, Lajos , Kalinsky, Kevin M. , Ademuyiwa, Foluso O. , Kato, Gregory J. , Kostic, Aleksandar David , Li, Michael , Specht, Jennifer M.

Cancer Research | February 15, 2018 | Volume: 78 | Issue: 4_Supplement | Pages: PD3-14-PD3-14

10.1158/1538-7445.sabcs17-pd3-14 Get It

Abstract Background LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which disrupts microtubulin and induces apoptosis. Methods This ongoing, phase 1 study evaluates safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC are eligible. Pts with ≥ Grade 2 neuropathy are excluded. Response is assessed per RECIST v1.1; pts with stable disease (SD) or better can continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts. Tumor biopsies are evaluated for LIV-1 expression. Results To date, 69 pts (18 HR+/HER2–, 51 TN) have received a median of 3 cycles (range, 1–12) of SGN-LIV1A at doses of 0.5–2.8 mg/kg. Median age was 56 yrs. Pts had a median of 3 prior cytotoxic regimens for LA/MBC; 58 had visceral disease and 37 had bone metastases. No dose-limiting toxicities (DLTs) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Expansion cohorts of TN pts were opened at 2.0 and 2.5 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥25% of pts were fatigue (59%), nausea (51%), peripheral neuropathy (44%), alopecia (36%), decreased appetite (33%), constipation (30%), abdominal pain, diarrhea, and neutropenia (25% each). Most AEs were Grade 1/2; AEs ≥ Grade 3 included neutropenia (25%) and anemia (15%). Febrile neutropenia occurred in 2 pts whose total dose exceeded 200 mg per cycle, including 1 treatment-related death due to sepsis. No other treatment-related deaths occurred on-study. Seven pts discontinued treatment due to AEs. In dose escalation, activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR= CR+PR+SD) of 59% (10 SD), including 1 pt with SD ≥24 wks. Among the 44 EE TN pts (dose escalation plus expansion cohorts), the objective response rate (ORR) was 32% (14 PR) with a confirmed PR rate of 21%, DCR was 64% (14 PR, 14 SD), and clinical benefit rate (CBR=CR+PR+SD ≥24 wks) was 36% (16 pts). For TN pts, median PFS was 11.3 wks (95% CI: 6.1, 17.1); 10 pts remain on treatment. Of 631 MBC tumor samples of all clinical subtypes evaluated for LIV-1, 91% were positive; 75% had moderate-to-high expression (H-score ≥100). Conclusions LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy was generally well tolerated and showed encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 32%, confirmed PR rate of 21%, and CBR (≥24 wks) of 36%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort. Citation Format: Modi S, Pusztai L, Forero A, Mita M, Miller KD, Weise A, Krop I, Burris III H, Kalinsky K, Tsai M, Liu MC, Hurvitz SA, Wilks S, Ademuyiwa F, Diab S, Han HS, Kato G, Nanda R, O'Shaughnessy J, Kostic A, Li M, Specht J. Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer [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 PD3-14.
Abstract GS3-08: Pathological complete response predicts event-free and distant disease-free survival in the I-SPY2 TRIAL
DeMichele, A., Symmans, F., Albain, KS, Hylton, NM, Forero‐Torres, Andres , Veer, LJ van't, Perlmutter, Jane , Rugo, HS, Melisko, Michelle , Krings, Gregor , Datnow, Brian, Hasteh, Farnaz, Tipps, Ann , Weidner, Noel, Tickman, Ronald, Thornton, Steven , Amin, K M, Chen, B, Keeney, Gary L., Ocal, Tolgay I., Klipfel, Nancy, Sattar, Husain, Mueller, Jeffery, Gwin, K, Zeck, Jay , Duan, Xiuzhen, Erşahin, Çağatay, Gamez, R, Troxell, Megan L. , Mansoor, Adnan , LeBeau, Lauren, Sams, Sharon B. , Wisell, J. , Wei, Shi , Vinh, Tuyethoa N., Stamatakos, MD, Tawfik, Ossama , Rendi, Mara H. , Minton, S., Magliocco, Anthony M., Sahoo, Sunati , Fang, Y, Singhrao, Ruby , Asare, SM, Wallace, AM, Chien, AJ, Ellis, ED, Han, HS, Clark, AS, Boughey, JC , Elias, AD, Nanda, Rita , Korde, Larissa A. , Northfelt, Donald W. , Edmiston, KK, Viscusi, Rebecca K., Haley, Barbara , Kemmer, Kathleen, Zelnak, Amelia, Berry, DA, Esserman, L., Yee, Douglas , Isaacs, Claudine , Yau, Christina , Chen, Yung‐Yi , Balassanian, Ronald , Zhang, Hongtao , Thornton, S, Ritter, Jacob , Klein, Martin , Feldman, Michael D. , Baker, Gabrielle M. , Kallakury, Bhaskar , Harada, Shuko , Fan, F, Adams, Amy Louise , Fang, Y, Hirst, Gillian L. , Murthy, Ravi , Lang, Julie E. , Khan, Qamar J.

Cancer Research | February 15, 2018 | Volume: 78 | Issue: 4_Supplement | Pages: GS3-08-GS3-08

10.1158/1538-7445.sabcs17-gs3-08 Get It

Abstract Background: Pathological complete response (pCR) is accepted by FDA as a surrogate endpoint for accelerated approval of targeted agents in combination with chemotherapy based on better long-term outcomes compared to residual disease (Cortazar 2014). Methods: The multi-center, adaptively-randomized I-SPY2 platform trial uses pCR as the primary endpoint to identify investigational agents that will improve outcomes in women with stage 2/3 breast cancer with high risk of early recurrence, across all signatures, based on hormone receptor (HR), HER2, and 70-gene (MammaPrint) status. For patients with HR+ HER2- tumors, only 70-gene (Mammaprint) high-risk patients are enrolled. To date, 1200+ patients have been randomized to one of 14 arms: control (paclitaxel followed by AC); veliparib/carboplatin; neratinib; MK2206; trebananib; trastuzumab/pertuzumab; ado-trastuzumab emtansine/pertuzumab; pembrolizumabx4; ganitumab/metformin; ganetespib; PLX-3397. 7 agents graduated in at least one signature (> 85% probability of success in a 300-patient phase III confirmatory trial); 2 did not graduate; 1 stopped for toxicity, and 3 are enrolling (patritumab/trastuzumab, talazoparib/irinotecan, pembrolizumabx8). Local pathologists were centrally trained using the Residual Cancer Burden (RCB) assessment to ensure uniform evaluation and response classification; RCB 0 = pCR. Results: We evaluated the relationship between pCR and event free (EFS) and distant disease free survival (DDFS) in the first 522 pts (median follow-up:2.5 years). 180 pts achieved pCR (36%) while 338 did not (RCB=1-3). There were 82 EFS and 65 DRFS events. Over the entire group (including all arms), pCR was highly associated with 3-year EFS (p<0.001 for both). Pts achieving pCR had a 3% recurrence risk (RR) at 3 years; those with non-pCR had 24% RR over this time period. For distant recurrence, the 3-year RR with pCR was 2%, compared to 20% in pts with non-pCR. As expected, pCR rates varied by breast cancer subtype (HR+/HER2: 18% (35/196), HR+/HER2+: 40% (33/82), HR-/HER2+:68% (34/50), HR-/HER2-:41% (76/188)). The relationship between pCR and EFS was significant and clinically impactful within each subtype. 3-year survival (pCR group)Hazard Ratio OverallOverallHR+/HER2-HER2+TNBCEFS97%0.08 (0.03-0.23)0.14 (0.02-1.04)0 (NA)0.11 (0.03-0.37)DDFS98%0.08 (0.03-0.26)0.17 (0.01-1.23)0 (NA)0.09 (0.02-0.40) Conclusions: The first long-term efficacy results from the I-SPY2 TRIAL demonstrate that achieving pCR is a very strong surrogate endpoint for improved EFS and DDFS in a high-risk population, across all treatment arms, regardless of subtype. I-SPY2 shows substantially lower estimated EFS hazards for patients achieving pCR, compared to the 5 yr EFS hazard ratio for pCR vs not in Cortazar (hazard ratio 0.49), demonstrating important differences between a metaanalysis compared to a platform trial with uniform high-risk eligibility, standardized pathology assessment, and multiple targeted therapies. Our data support the use of pCR as a primary endpoint for accelerated approval of new drugs if EFS is evaluated in the same population. Based on these findings, the I-SPY2 TRIAL will test whether therapy can be deescalated or escalated for individual patients with the goal of achieving pCR for all. Citation Format: Yee D, DeMichele A, Isaacs C, Symmans F, Yau C, Albain KS, Hylton NM, Forero-Torres A, van't Veer LJ, Perlmutter J, Rugo HS, Melisko M, Chen Y-Y, Balassanian R, Krings G, Datnow B, Hasteh F, Tipps A, Weidner N, Zhang H, Tickman R, Thornton S, Ritter J, Amin K, Klein M, Chen B, Keeney G, Ocal T, Feldman M, Klipfel N, Sattar H, Mueller J, Gwin K, Baker G, Kallakury B, Zeck J, Duan X, Ersahin C, Gamez R, Troxell M, Mansoor A, Grasso LeBeau L, Sams S, Wisell J, Wei S, Harada S, Vinh T, Stamatakos MD, Tawfik O, Fan F, Adams A, Rendi M, Minton S, Magliocco A, Sahoo S, Fang Y, Hirst G, Singhrao R, Asare SM, Wallace AM, Chien AJ, Ellis ED, Han HS, Clark AS, Boughey JC, Elias AD, Nanda R, Korde L, Murthy R, Lang J, Northfelt D, Khan Q, Edmiston KK, Viscusi R, Haley B, Kemmer K, Zelnak A, Berry DA, Esserman LJ. Pathological complete response predicts event-free and distant disease-free survival in the I-SPY2 TRIAL [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 GS3-08.
Selective Inhibition of Nuclear Export With Oral Selinexor for Treatment of Relapsed or Refractory Multiple Myeloma
Dingli, David , Cornell, Robert F. , Huff, Carol Ann , Bhutani, Divaya , Zonder, Jeffrey A. , Cole, Craig E. , Vij, Ravi , Abonour, Rafat , Schiller, Gary J. , Parker, Terri L., Costa, Luciano J. , Kaminetzky, David , Hoffman, James E. , Chari, Ajai , Wier, Scott Van, Ahmann, Gregory , Lopez, Ilsel, Kauffman, Michael , Shacham, Sharon, Saint-Martin, Jean-Richard, Picklesimer, Carla, Choe-Juliak, Cassandra, Stewart, A. Keith, Vogl, Dan T. , Cornell, Robert Frank, Zonder, Jeffrey, Nooka, Ajay, Richter, Joshua , Cole, Craig, Schiller, Gary, Yee, Andrew J. , Van Wier, Scott, Picklesimer, Carla D, Chari, Ajai , Dingli, David , Bhutani, Divaya , Costa, Luciano J , Jagannath, Sundar , Baz, Rachid , Nooka, Ajay K. , Jakubowiak, Andrzej , Yee, Andrew J , Siegel, David S. , Fonseca, Rafaël

Journal of Clinical Oncology | January 30, 2018 | Volume: 36 | Issue: 9 | Pages: 859-866

10.1200/jco.2017.75.5207 | PMID 29381435 Get It

Purpose Selinexor, a first-in-class, oral, selective exportin 1 (XPO1) inhibitor, induces apoptosis in cancer cells through nuclear retention of tumor suppressor proteins and the glucocorticoid receptor, along with inhibition of translation of oncoprotein mRNAs. We studied selinexor in combination with low-dose dexamethasone in patients with multiple myeloma refractory to the most active available agents. Patients and Methods This phase II trial evaluated selinexor 80 mg and dexamethasone 20 mg, both orally and twice weekly, in patients with myeloma refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide (quad-refractory disease), with a subset also refractory to an anti-CD38 antibody (penta-refractory disease). The primary end point was overall response rate (ORR). Results Of 79 patients, 48 had quad-refractory and 31 had penta-refractory myeloma. Patients had received a median of seven prior regimens. The ORR was 21% and was similar for patients with quad-refractory (21%) and penta-refractory (20%) disease. Among patients with high-risk cytogenetics, including t(4;14), t(14;16), and del(17p), the ORR was 35% (six of 17 patients). The median duration of response was 5 months, and 65% of responding patients were alive at 12 months. The most common grade ≥ 3 adverse events were thrombocytopenia (59%), anemia (28%), neutropenia (23%), hyponatremia (22%), leukopenia (15%), and fatigue (15%). Dose interruptions for adverse events occurred in 41 patients (52%), dose reductions occurred in 29 patients (37%), and treatment discontinuation occurred in 14 patients (18%). Conclusion The combination of selinexor and dexamethasone has an ORR of 21% in patients with heavily pretreated, refractory myeloma with limited therapeutic options.
Hormone therapy and urine protein excretion: a multiracial cohort study, systematic review, and meta-analysis
Kattah, Andrea G. , Milić, Nataša , Kantarci, Kejal , Zeydan, Burcu , Kardia, Sharon L. R., Suarez, Maria L G, Turner, Stephen T. , Garovic, Vesna D. , Milic, N , Kantarci, Kejal , Zeydan, Burcu , Suarez, Maria Lourdes Gonzalez , Mosley, Thomas H. , Ware, Erin Bakshis

Menopause | January 29, 2018 | Volume: 25 | Issue: 6 | Pages: 625-634

10.1097/gme.0000000000001062 | PMID 29381664 Get It

Abstract Objective: Experimental models suggest estrogen has a renoprotective effect, but human studies show variable results. Our objective was to study the association of hormone therapy (HT) and albuminuria in postmenopausal women and to synthesize the results with outcomes from prior studies. Methods: We analyzed data from postmenopausal women who participated in the second study visit (2000-2004) of the Genetic Epidemiology Network of Arteriopathy (GENOA) study. The exposure was self-reported HT use and the outcome was albuminuria (urine albumin-to-creatinine ratio >25 mg/g creatinine). We also conducted a systematic review and meta-analysis on the association of HT and urine protein in postmenopausal women. Continuous and dichotomous measures of protein excretion were converted to a standardized mean difference (SMD) for each study. Results: In the GENOA cohort ( n = 2,217), there were fewer women with albuminuria among HT users than nonusers (9% vs 19%, P < 0.001). HT use was associated with decreased odds of albuminuria (odds ratio 0.65, 95% confidence interval (CI), 0.45-0.95), after adjusting for significant differences in age, race, education, comorbidities, and the age at and cause of menopause. The SMD of the effect of HT on urine proteinuria/albuminuria in the randomized control trials ( n = 3) was 0.02 (95% CI, −0.29 to 0.33) and −0.13 (95% CI, −0.31 to 0.05) in the observational studies ( n = 9). There was significantly less albuminuria among HT users (SMD −0.15, 95% CI, −0.27 to −0.04) in the 9 studies that only reported albuminuria as an outcome and in the 10 studies with a comparator arm (SMD −0.15, 95% CI, −0.26 to −0.04). Conclusions: HT is associated with decreased odds of albuminuria, but some of the observed benefits may be related to reported outcomes, the presence of a comparator arm, and the type of study design.
Issues Surrounding Age-Adjusted d-Dimer Cutoffs That Practicing Physicians Need to Know When Evaluating Patients With Suspected Pulmonary Embolism
Goodwin, Andrew , Higgins, Russell A. , Moser, Karen , Smock, Kristi J. , Chandler, Wayne L. , Kottke‐Marchant, Kandice, Hartman, Sarah K., Volod, Oksana , Brown, Alan F., Johari, Vandita, Burr, Sharon, Polyakov, Nataliya, Chen, Dong , Goodwin, Andrew J, Moser, Karen A, Johari, Vandita P, Chen, Dong , Brown, Alan F.

Annals of Internal Medicine | January 24, 2018 | Volume: 166 | Issue: 5 | Pages: 361-363

10.7326/m16-2030 | PMID 28024301 Get It

Ethical Considerations Related to Return of Results from Genomic Medicine Projects: The eMERGE Network (Phase III) Experience
Fossey, Robyn, Kochan, David C., Winkler, Erin, Pacyna, Joel E. , Thibodeau, Stephen N. , Connolly, John J. , Harr, Margaret , Behr, Meckenzie, Prows, Cynthia A. , Cobb, Beth L., Myers, Melanie F. , Leslie, Nancy, Namjou‐Khales, Bahram, Rasouly, Hila Milo , Wynn, Julia , Fedotov, Alexander , Gharavi, Ali G. , Williams, Janet L. , Pais, Lynn , Holm, Ingrid A. , Aufox, Sharon , Smith, Maureen E. , Scrol, Aaron, Leppig, Kathleen A. , Jarvik, Gail P. , Wiesner, Georgia L. , Li, Rongling, Stroud, Mary , Sharp, Richard R. , Kochan, David, Thibodeau, Stephen, Myers, Melanie F , Holm, Ingrid A , Sharp, Richard R , Milo Rasouly, Hila , Jarvik, Gail P , Connolly, John J , Olson, Janet E. , Chung, Wendy K. , Smoller, Jordan W. , Kullo, Iftikhar J.

Journal of Personalized Medicine | January 3, 2018 | Volume: 8 | Issue: 1 | Pages: 2

10.3390/jpm8010002 | PMID 29301385 Get It

We examined the Institutional Review Board (IRB) process at 9 academic institutions in the electronic Medical Records and Genomics (eMERGE) Network, for proposed electronic health record-based genomic medicine studies, to identify common questions and concerns. Sequencing of 109 disease related genes and genotyping of 14 actionable variants is being performed in ~28,100 participants from the 9 sites. Pathogenic/likely pathogenic variants in actionable genes are being returned to study participants. We examined each site’s research protocols, informed-consent materials, and interactions with IRB staff. Research staff at each site completed questionnaires regarding their IRB interactions. The time to prepare protocols for IRB submission, number of revisions and time to approval ranged from 10–261 days, 0–11, and 11–90 days, respectively. IRB recommendations related to the readability of informed consent materials, specifying the full range of potential risks, providing options for receiving limited results or withdrawal, sharing of information with family members, and establishing the mechanisms to answer participant questions. IRBs reviewing studies that involve the return of results from genomic sequencing have a diverse array of concerns, and anticipating these concerns can help investigators to more effectively engage IRBs.
Fallacy of indexing renal and systemic hemodynamic measurements for body surface area
Reilly, Sharon L., Turner, Stephen T.

American Journal of Physiology-Regulatory, Integrative and Comparative Physiology | December 24, 2017 | Volume: 268 | Issue: 4 | Pages: R978-R988

10.1152/ajpregu.1995.268.4.r978 | PMID 7733408 Get It

Renal plasma flow, glomerular filtration rate, and cardiac output are traditionally indexed for body surface area by expressing these traits as per-surface-area ratios. Indexing is intended to remove interindividual variation attributable to differences in body size. Regression is an alternative method commonly used to adjust other biological traits for the effects of a covariate, such as body surface area. The purpose of this study was to compare the indexing and regression methods of adjusting renal plasma flow, glomerular filtration rate, and cardiac output for interindividual differences in body surface area. We estimated renal plasma flow by the clearance of p-aminohippurate, glomerular filtration rate by clearance of inulin, and cardiac output by thoracic electrical impedance in a sample of 78 unrelated females and 78 unrelated males (ages 20-49.9 yr) from the general population of Rochester, MN. The indexing method created negative dependencies of renal plasma flow and cardiac output on body surface area and failed to eliminate the positive dependency of glomerular filtration rate on body surface area. Moreover, indexing obscured differences in mean renal plasma flow between females and males and created differences in mean cardiac output between the genders. In contrast, the regression method consistently eliminated dependencies of each trait on body surface area and did not lead to inappropriate inferences about mean differences in these traits between females and males. We conclude that the indexing method of adjusting renal plasma flow, glomerular filtration rate, and cardiac output for interindividual differences in body surface area should be abandoned and replaced by use of the regression method.
Role of prostaglandins and renal nerves in the renal actions of adrenomedullin
Jougasaki, Michihisa , Aarhus, L L, Heublein, D. M., Sandberg, S. M., Burnett, J. C., Heublein, Denise M., Sandberg, Sharon M.

American Journal of Physiology-Renal Physiology | December 23, 2017 | Volume: 272 | Issue: 2 | Pages: F260-F266

10.1152/ajprenal.1997.272.2.f260 | PMID 9124405 Get It

Adrenomedullin (ADM), originally discovered in human pheochromocytoma, is also of renal cell origin and has natriuretic and diuretic actions. The present study was designed to investigate the role of prostaglandins and renal nerves in the renal hemodynamic and natriuretic actions ofADM. ADM was administered intrarenally (1, 5 and 25 ng x kg(-1) x min(-1)) with and without prostaglandin inhibition (meclofenamate, 5 mg/kg intravenous bolus) in anesthetized normal mongrel dogs (n = 5, each). To elucidate the role of renal nerves, ADM was administered intrarenally to the denervated kidney in five dogs. ADM mediated a natriuretic action via increases in glomerular filtration rate and decreases in distal tubular sodium reabsorption, which was attenuated by renal denervation and completely abolished by prostaglandin inhibition. The renal vasodilatation induced by ADM was attenuated by meclofenamate, as well as by renal denervation, although not significantly. Additionally, renal nerves mediated hemodynamic effects of hypertension that were produced by intrarenal infusion of ADM. This study establishes an important mechanistic role for renal prostaglandins as a mediator of ADM-mediated natriuresis at the level of the glomerulus and terminal nephron.
Renal localization and actions of adrenomedullin: a natriuretic peptide
Jougasaki, Michihisa , Wei, C , Aarhus, L L, Heublein, Denise M., Sandberg, S. M., Burnett, John C. , Sandberg, Sharon M.

American Journal of Physiology-Renal Physiology | December 23, 2017 | Volume: 268 | Issue: 4 | Pages: F657-F663

10.1152/ajprenal.1995.268.4.f657 | PMID 7733322 Get It

Adrenomedullin (ADM) is a newly described 52-amino acid peptide originally isolated from extracts of human pheochromocytoma and, more recently, detected in human plasma. Based on the report that ADM mRNA and immunoreactivity are present in the kidney, the current study was designed to determine the renal distribution of ADM by immunohistochemistry and the renal biological actions of ADM. In the immunohistochemical studies, the present investigation demonstrated the localization of ADM in glomeruli, cortical distal tubules, and medullary collecting duct cells of the normal canine kidney. In the in vivo studies, ADM was administered (0.25 ng.kg-1.min-1 in group I and 1, 5, and 25 ng.kg-1.min-1 in group II) intrarenally in normal mongrel dogs with the contralateral kidney receiving only saline vehicle. Intrarenal infusion of ADM resulted in a marked diuretic and natriuretic response, whereas the contralateral kidney showed no renal effects. These significant natriuresis and diuresis in the ADM kidney were associated with increases in glomerular filtration rate and fractional sodium excretion and with a decrease in distal tubular sodium reabsorption. Intrarenal infusion of ADM also caused an increase in mean arterial blood pressure and a decrease in heart rate. Plasma concentrations of atrial natriuretic peptide, renin activity, aldosterone, and guanosine 3',5'-cyclic monophosphate were not changed during the infusion of ADM. The current study demonstrates that ADM is present in renal glomerular and tubular cells and is a potent natriuretic peptide that may play an important role in the regulation of sodium excretion.
Leg mass and lower body negative pressure tolerance in men and women
Lawler, Lori A., Halliwill, John R. , Summer, Jolene M., Joyner, Michael J. , Mulvagh, Sharon L.

Journal of Applied Physiology | December 22, 2017 | Volume: 85 | Issue: 4 | Pages: 1471-1475

10.1152/jappl.1998.85.4.1471 | PMID 9760343 Get It

To explore the hypothesis that lower body muscle mass correlates with orthostatic tolerance, 18 healthy volunteers (age 18–48 yr; 10 men, 8 women) underwent a graded lower body negative pressure (LBNP) protocol consisting of six, 5-min stages of suction up to 60 mmHg in 10-mmHg increments. Forearm blood flow, heart rate, and blood pressure were measured, and forearm vascular resistance was calculated. Leg muscle mass was assessed by dual-energy X-ray absorptiometry. All subjects received standard intravenous hydration for at least 8 h before the study. Six men and four women completed all stages of LBNP. Four men and four women developed presyncopal symptoms, including marked bradycardia and/or hypotension, at LBNP levels of 30 mmHg ( n = 2; 1 man, 1 woman), 40 mmHg ( n = 2; 1 man, 1 woman), and 50 mmHg ( n = 4; 2 men, 2 women). The presyncopal subjects had leg muscle masses ranging from 19.5 to 25.2 kg in men and from 11.7 to 16.6 kg in women. In subjects who completed all stages of LBNP, leg muscle mass ranged from 17.5 to 24.1 kg in men and from 10.4 to 18.0 kg in women. Leg muscle mass did not differ between presyncopal subjects and those who completed the protocol. Furthermore, there were no differences in the hemodynamic responses to LBNP between subjects with low vs. high leg mass. These data suggest that leg muscle mass is not a critical determinant of LBNP tolerance in otherwise healthy men and women.