Perfluorocarbons cause thrombocytopenia, changes in RBC morphology and death in a baboon model of systemic inflammation

A perfluorocarbon (PFC) investigated for treatment of traumatic brain injury (TBI) delivers oxygen to support brain function, but causes transient thrombocytopenia. TBI can cause acute inflammation with resulting thrombocytopenia; an interaction between the PFC effects and TBI inflammation might exacerbate thrombocytopenia. Therefore, PFC effects on platelet (PLT) function and hemostasis in a lipopolysaccharide (LPS) model of inflammation in the baboon were studied. Animals were randomized to receive saline ±LPS, and ± one of two doses of PFC. PLT count, transmission electron microscopy, and microparticle populations were quantified at baseline (BL) and at 2, 24, 48, 72, and 96 hours; hemostatic parameters for aggregometry and for blood clotting were measured at baseline (BL) and days 3 and 4. Injection of vehicle and LPS caused thrombocytopenia within hours; PFCs caused delayed thrombocytopenia beginning 48 hours post-infusion. LPS+PFC produced a more prolonged PLT decline and decreased clot strength. LPS+PFC increased ADP-stimulated aggregation, but PFC alone did not. Microparticle abundance was greatest in the LPS+PFC groups. LPS+PFC caused diffuse microvascular hemorrhage and death in 2 of 5 baboons in the low dose LPS-PFC group and 2 of 2 in the high dose LPS-PFC group. Necropsy and histology suggested death was caused by shock associated with hemorrhage in multiple organs. Abnormal morphology of platelets and red blood cells were notable for PFC inclusions. In summary, PFC infusion caused clinically significant thrombocytopenia and exacerbated LPS-induced platelet activation. The interaction between these effects resulted in decreased hemostatic capacity, diffuse bleeding, shock and death.

Postnatal persistence of nonhuman primate sex-dependent renal structural and molecular changes programmed by intrauterine growth restriction

BACKGROUND

Poor nutrition during fetal development programs postnatal kidney function. Understanding postnatal consequences in nonhuman primates (NHP) is important for translation to our understanding the impact on human kidney function and disease risk. We hypothesized that intrauterine growth restriction (IUGR) in NHP persists postnatally, with potential molecular mechanisms revealed by Western-type diet challenge.

METHODS

IUGR juvenile baboons were fed a 7-week Western diet, with kidney biopsies, blood, and urine collected before and after challenge. Transcriptomics and metabolomics were used to analyze biosamples.

RESULTS

Pre-challenge IUGR kidney transcriptome and urine metabolome differed from controls. Post-challenge, sex and diet-specific responses in urine metabolite and renal signaling pathways were observed. Dysregulated mTOR signaling persisted postnatally in female pre-challenge. Post-challenge IUGR male response showed uncoordinated signaling suggesting proximal tubule injury.

CONCLUSION

Fetal undernutrition impacts juvenile offspring kidneys at the molecular level suggesting early-onset blood pressure dysregulation.

Blood pressure and the kidney cortex transcriptome response to high-sodium diet challenge in female nonhuman primates

Blood pressure (BP) is influenced by genetic variation and sodium intake with sex-specific differences; however, studies to identify renal molecular mechanisms underlying the influence of sodium intake on BP in nonhuman primates (NHP) have focused on males. To address the gap in our understanding of molecular mechanisms regulating BP in female primates, we studied sodium-naïve female baboons (n = 7) fed a high-sodium (HS) diet for 6 wk. We hypothesized that in female baboons variation in renal transcriptional networks correlates with variation in BP response to a high-sodium diet. BP was continuously measured for 64-h periods throughout the study by implantable telemetry devices. Sodium intake, blood samples for clinical chemistries, and ultrasound-guided kidney biopsies were collected before and after the HS diet for RNA-Seq and bioinformatic analyses. We found that on the LS diet but not the HS diet, sodium intake and serum 17 β-estradiol concentration correlated with BP. Furthermore, kidney transcriptomes differed by diet-unbiased weighted gene coexpression network analysis revealed modules of genes correlated with BP on the HS diet but not the LS diet. Our results showed variation in BP on the HS diet correlated with variation in novel kidney gene networks regulated by ESR1 and MYC; i.e., these regulators have not been associated with BP regulation in male humans or rodents. Validation of the mechanisms underlying regulation of BP-associated gene networks in female NHP will inform better therapies toward greater precision medicine for women.

Similar hemostatic responses to hypovolemia induced by hemorrhage and lower body negative pressure reveal a hyperfibrinolytic subset of non-human primates

BACKGROUND

To study central hypovolemia in humans, lower body negative pressure (LBNP) is a recognized alternative to blood removal (HEM). While LBNP mimics the cardiovascular responses of HEM in baboons, similarities in hemostatic responses to LBNP and HEM remain unknown in this species.

METHODS

Thirteen anesthetized baboons were exposed to progressive hypovolemia by HEM and, four weeks later, by LBNP. Hemostatic activity was evaluated by plasma markers, thromboelastography (TEG), flow cytometry, and platelet aggregometry at baseline (BL), during and after hypovolemia.

RESULTS

BL values were indistinguishable for most parameters although platelet count, maximal clot strength (MA), protein C, thrombin anti-thrombin complex (TAT), thrombin activatable fibrinolysis inhibitor (TAFI) activity significantly differed between HEM and LBNP. Central hypovolemia induced by either method activated coagulation; TEG R-time decreased and MA increased during and after hypovolemia compared to BL. Platelets displayed activation by flow cytometry; platelet count and functional aggregometry were unchanged. TAFI activity and protein, Factors V and VIII, vWF, Proteins C and S all demonstrated hemodilution during HEM and hemoconcentration during LBNP, whereas tissue plasminogen activator (tPA), plasmin/anti-plasmin complex, and plasminogen activator inhibitor-1 did not. Fibrinolysis (TEG LY30) was unchanged by either method; however, at BL, fibrinolysis varied greatly. Post-hoc analysis separated baboons into low-lysis (LY30 <2%) or high-lysis (LY30 >2%) whose fibrinolytic state matched at both HEM and LBNP BL. In high-lysis, BL tPA and LY30 correlated strongly (r = 0.95; P<0.001), but this was absent in low-lysis. In low-lysis, BL TAFI activity and tPA correlated (r = 0.88; P<0.050), but this was absent in high-lysis.

CONCLUSIONS

Central hypovolemia induced by either LBNP or HEM resulted in activation of coagulation; thus, LBNP is an adjunct to study hemorrhage-induced pro-coagulation in baboons. Furthermore, this study revealed a subset of baboons with baseline hyperfibrinolysis, which was strongly coupled to tPA and uncoupled from TAFI activity.

THE CRITICAL ROLE OF NONHUMAN PRIMATES IN MEDICAL RESEARCH

The sponsors of this report endorse carefully regulated research with nonhuman primates. This research is essential to learning about the biology, treatment and prevention of diseases and conditions that cause human suffering.

Primate response to angiotensin infusion and high sodium intake differ by sodium lithium countertransport phenotype

An increased level of sodium-lithium countertransport (SLC) activity has been associated with salt-sensitive hypertension. Previous findings have suggested that dysregulation of the renin-angiotensin-aldosterone system (RAAS) may be involved in the mechanism linking elevated SLC activity and hypertension. Therefore, baboons with different levels of SLC activity were given two diets differing in sodium content, with and without an angiotensin II (ANG II) infusion, to investigate the relationship between SLC activity, the RAAS, and physiological regulation by sodium. Although we anticipated that high SLC activity would be associated with inappropriate function of the RAAS and greater arterial pressure sensitivity to dietary sodium and ANG II and that low SLC activity would be associated with the least BP sensitivity, we found that the low SLC phenotype correlated with BP sensitivity similar to the high SLC phenotype, and the normal SLC phenotype showed the least BP sensitivity to dietary sodium and ANG II.

A Non-Human Primate Model of Severe Pneumococcal Pneumonia

RATIONALE

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and infectious death in adults worldwide. A non-human primate model is needed to study the molecular mechanisms that underlie the development of severe pneumonia, identify diagnostic tools, explore potential therapeutic targets, and test clinical interventions during pneumococcal pneumonia.

OBJECTIVE

To develop a non-human primate model of pneumococcal pneumonia.

METHODS

Seven adult baboons (Papio cynocephalus) were surgically tethered to a continuous monitoring system that recorded heart rate, temperature, and electrocardiography. Animals were inoculated with 109 colony-forming units of S. pneumoniae using bronchoscopy. Three baboons were rescued with intravenous ampicillin therapy. Pneumonia was diagnosed using lung ultrasonography and ex vivo confirmation by histopathology and immunodetection of pneumococcal capsule. Organ failure, using serum biomarkers and quantification of bacteremia, was assessed daily.

RESULTS

Challenged animals developed signs and symptoms of pneumonia 4 days after infection. Infection was characterized by the presence of cough, tachypnea, dyspnea, tachycardia and fever. All animals developed leukocytosis and bacteremia 24 hours after infection. A severe inflammatory reaction was detected by elevation of serum cytokines, including Interleukin (IL)1Ra, IL-6, and IL-8, after infection. Lung ultrasonography precisely detected the lobes with pneumonia that were later confirmed by pathological analysis. Lung pathology positively correlated with disease severity. Antimicrobial therapy rapidly reversed symptomology and reduced serum cytokines.

CONCLUSIONS

We have developed a novel animal model for severe pneumococcal pneumonia that mimics the clinical presentation, inflammatory response, and infection kinetics seen in humans. This is a novel model to test vaccines and treatments, measure biomarkers to diagnose pneumonia, and predict outcomes.

Central GIP signaling stimulates peripheral GIP release and promotes insulin and pancreatic polypeptide secretion in nonhuman primates

Glucose-dependent insulinotropic polypeptide (GIP) has important actions on whole body metabolic function. GIP and its receptor are also present in the central nervous system and have been linked to neurotrophic actions. Metabolic effects of central nervous system GIP signaling have not been reported. We investigated whether centrally administered GIP could increase peripheral plasma GIP concentrations and influence the metabolic response to a mixed macronutrient meal in nonhuman primates. An infusion and sampling system was developed to enable continuous intracerebroventricular (ICV) infusions with serial venous sampling in conscious nonhuman primates. Male baboons (Papio sp.) that were healthy and had normal body weights (28.9 ± 2.1 kg) were studied (n = 3). Animals were randomized to receive continuous ICV infusions of GIP (20 pmol·kg^-1·h^-1) or vehicle before and over the course of a 300-min mixed meal test (15 kcal/kg, 1.5g glucose/kg) on two occasions. A significant increase in plasma GIP concentration was observed under ICV GIP infusion (66.5 ± 8.0 vs. 680.6 ± 412.8 pg/ml, P = 0.04) before administration of the mixed meal. Increases in postprandial, but not fasted, insulin (P = 0.01) and pancreatic polypeptide (P = 0.04) were also observed under ICV GIP. Effects of ICV GIP on fasted or postprandial glucagon, glucose, triglyceride, and free fatty acids were not observed. Our data demonstrate that central GIP signaling can promote increased plasma GIP concentrations independent of nutrient stimulation and increase insulin and pancreatic polypeptide responses to a mixed meal.

Abstract 82: Development of the baboon as an animal model for adult T-cell leukemia/lymphoma

Background:

Adult T-cell leukemia/lymphoma (ATLL) is a T-cell lymphoma that can be found in the blood (leukemia), lymph nodes (lymphoma), or many areas of the body. ATLL has been linked to infection by the human T-cell lymphotropic virus type 1 (HTLV-1). HTLV-1 infects millions of people worldwide. However, less than five percent of individuals with the HTLV-1 will develop HTLV-associated diseases such as ATLL (d'Offay et al. 2007). The simian counterpart of HTLV-1 is the Simian T-cell leukemia virus-1 (STLV-1). STLV-1 is endemic in Old World monkeys including baboons, and has been linked to lymphomas in nonhuman primates (Takemura et al 2002, Saksena et al. 1994, d'Offay et al. 2007). Lymphoma is the most common neoplasm of nonhuman primates (Hubbard et al. 1993, Hunt et al 1983). Some baboons naturally infected with STLV-1 develop leukemia/lymphoma that shares clinical and pathological features with human ATLL (Hubbard et al. 1993, Schatzl et al 1993). At Texas Biomed we have a large population of pedigreed baboons, some are infected with STLV-1.

The aim of our study was to investigate the relationship between STLV-1 infection and ATLL in a captive baboon colony and to develop the baboon as a model to study the link between retroviruses and ATLL.

Methods:

We reviewed the pathology reports of 135 baboons that went for necropsy during the years of 1991-2014 that had a diagnosis of lymphosarcoma which involved non-lymphoid organs.

Results:

The most common clinical finding was generalized lymphadenopathy and weight loss. Microscopic examination indicated that in most animals neoplastic cells were found in most organs. Organs were effaced by a uniform population of small, well differentiated lymphocytes with occasional mitoses. Also, the lymph nodes and the splenic white pulp contained increased numbers of lymphocytes with multifocal disorganization of the preexistent architecture. Other than the lymphoid organs, the lungs were the organ involved most (&gt;90%). Other organs involved included kidney (56%), liver (60%), heart (46%), skin (9%) and eye (3%). Using Immunohistochemistry the neoplastic cells showed strong immunoreactivity for CD3 but were negative for CD79a and CD68.

Conclusions:

Due to the fact that baboons naturally infected with STLV-1 develop leukemia/lymphoma that shares clinical and pathological features with human ATLL, we recommend using the baboon as a useful model for studying the mode of transmission and therapies for ATLL.

Further studies:

We have initiated a study on the role of genetics in the pathogenicity STLV-1.

References:

Hubbard GB, Moné JP et al.1993; 43(4):301-9.

d'Offay JM, Eberle R et al. 2007;57(1):105-14.

Takemura T, Yamashita M et al. 2002;76(4):1642-8.

Saksena NK, Herve V et al.1994;198(1):297-310.

Hunt RD, Blake BJ et al.1983; 80(16):5085-9.

Schätzl H, Tschikobava M et al.1993;7 Suppl 2:S86-92.

Courgnaud V, Van Dooren S et al. 2004;78(9):4700-9.

Citation Format: Thushari Alahapperuma, James N. Mubiru, Alice Yang, Maggie Garcia-Forey, Edward J. Dick, Michael Owston, Robert E. Shade. Development of the baboon as an animal model for adult T-cell leukemia/lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 82. doi:10.1158/1538-7445.AM2014-82

Abstract 2347: PSA splice variants and their expression in prostate cancer

Introduction

Prostate cancer (PCa) is the second most common cancer in American men, resulting in 32,000 deaths annually. Challenges for the management of PCa include the inability to distinguish indolent from aggressive and untreatable castration-resistant PCa. These challenges can be addressed by understanding the molecular basis of cancer initiation and progression. Prostate specific antigen (PSA) is widely used for screening, diagnosing and monitoring of PCa, although it is also elevated in other disorders and therefore lacks specificity and sensitivity. Alternative splicing is a common mechanism used in nature to enhance protein diversity. Alternative splicing of the PSA gene produces at least 15 transcripts of 0.7-6.1 kb (Heuzé-Vourc'h et al 2003). Several variants of PSA have been reported and are shown to be differentially expressed in PCa compared to normal prostates or to benign prostatic hyperplasia (BPH).

Here we describe the identification of four variants of PSA with the potential to improve on the specificity of the PSA test.

Material and Methods

Human prostate cDNAs were from cryopreserved prostate tissues collected after radical prostatectomies and have been described previously (Mubiru et al. 2004). PCR was carried out using primers that amplify the complete PSA mRNA and also those specific for the most common splice variant (Heuzé-Vourc'h et al. 2001). The PCR products were inserted into the PCR2.1-TOPO vector (Life Technologies) and sequenced.

Results

We identified four novel splice variants of the PSA gene.

Novel PSA Splice VariantsTypeNameContaining Exons (Ex) and Introns (In)Molecular Weight (Da)pIPSA mRNAPSAEx3del246Ex1, Ex2, Partial Ex38,5949.61PSA mRNAPSA25RVEx1, Partial In111,1815.55PSA mRNAPSA Yang 28Ex1, Ex2, Ex514,1539.59PSA mRNAPSA Yang 21Ex1, Ex2, Partial Ex3, Ex4, Ex523,6986.64

Results also indicate that some transcripts are differentially expressed in tumors compared to non-tumors.

References

1.Mubiru JN, et al. (2004). Gene 327: 89-98.

2.Heuzé-Vourc'h N, et al. (2003) Eur J Biochem 270: 706-714.

3.Heuzé-Vourc'h N, et al. (2001) Eur J Biochem 268: 4408-4413.

Citation Format: Alice S. Yang, Thushari Alahapperuma, James N. Mubiru, Magdalena Garcia-Forey, Robert E. Shade. PSA splice variants and their expression in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2347. doi:10.1158/1538-7445.AM2014-2347

Baboons as a model to study genetics and epigenetics of human disease

A major challenge for understanding susceptibility to common human diseases is determining genetic and environmental factors that influence mechanisms underlying variation in disease-related traits. The most common diseases afflicting the US population are complex diseases that develop as a result of defects in multiple genetically controlled systems in response to environmental challenges. Unraveling the etiology of these diseases is exceedingly difficult because of the many genetic and environmental factors involved. Studies of complex disease genetics in humans are challenging because it is not possible to control pedigree structure and often not practical to control environmental conditions over an extended period of time. Furthermore, access to tissues relevant to many diseases from healthy individuals is quite limited. The baboon is a well-established research model for the study of a wide array of common complex diseases, including dyslipidemia, hypertension, obesity, and osteoporosis. It is possible to acquire tissues from healthy, genetically characterized baboons that have been exposed to defined environmental stimuli. In this review, we describe the genetic and physiologic similarity of baboons with humans, the ability and usefulness of controlling environment and breeding, and current genetic and genomic resources. We discuss studies on genetics of heart disease, obesity, diabetes, metabolic syndrome, hypertension, osteoporosis, osteoarthritis, and intrauterine growth restriction using the baboon as a model for human disease. We also summarize new studies and resources under development, providing examples of potential translational studies for targeted interventions and therapies for human disease.

Correlation between presence of Trypanosoma cruzi DNA in heart tissue of baboons and cynomolgus monkeys, and lymphocytic myocarditis

Trypanosoma cruzi, the causative agent of Chagas' disease, preferentially infects cardiac and digestive tissues. Baboons living in Texas (Papio hamadryas) and cynomolgus monkeys (Macaca fascicularis) have been reported to be infected naturally with T. cruzi. In this study, we retrospectively reviewed cases of animals that were diagnosed with lymphocytic myocarditis and used a polymerase chain reaction (PCR)-based method (S36/S35 primer set) to amplify T. cruzi DNA from archived frozen and formalin-fixed paraffin-embedded (FFPE) cardiac tissues. We show that the PCR method is applicable in archived frozen and FFPE tissues and the sensitivity is in the femtogram range. A positive correlation between PCR positivity and lymphocytic myocarditis in both baboons and cynomolgus monkeys is shown. We also show epicarditis as a common finding in animals infected with T. cruzi.

Validation of lower body negative pressure as an experimental model of hemorrhage

Lower body negative pressure (LBNP), a model of hemorrhage (Hem), shifts blood to the legs and elicits central hypovolemia. This study compared responses to LBNP and actual Hem in sedated baboons. Arterial pressure, pulse pressure (PP), central venous pressure (CVP), heart rate, stroke volume (SV), and +dP/dt were measured. Hem steps were 6.25%, 12.5%, 18.75%, and 25% of total estimated blood volume. Shed blood was returned, and 4 wk after Hem, the same animals were subjected to four LBNP levels which elicited equivalent changes in PP and CVP observed during Hem. Blood gases, hematocrit (Hct), hemoglobin (Hb), plasma renin activity (PRA), vasopressin (AVP), epinephrine (EPI), and norepinephrine (NE) were measured at baseline and maximum Hem or LBNP. LBNP levels matched with 6.25%, 12.5%, 18.75%, and 25% hemorrhage were -22 ± 6, -41 ± 7, -54 ± 10, and -71 ± 7 mmHg, respectively (mean ± SD). Hemodynamic responses to Hem and LBNP were similar. SV decreased linearly such that 25% Hem and matching LBNP caused a 50% reduction in SV. Hem caused a decrease in Hct, Hb, and central venous oxygen saturation (ScvO2). In contrast, LBNP increased Hct and Hb, while ScvO2 remained unchanged. Hem caused greater elevations in AVP and NE than LBNP, while PRA, EPI, and other hematologic indexes did not differ between studies. These results indicate that while LBNP does not elicit the same effect on blood cell loss as Hem, LBNP mimics the integrative cardiovascular response to Hem, and validates the use of LBNP as an experimental model of central hypovolemia associated with Hem.

The baboon kidney transcriptome: analysis of transcript sequence, splice variants, and abundance

The baboon is an invaluable model for the study of human health and disease, including many complex diseases of the kidney. Although scientists have made great progress in developing this animal as a model for numerous areas of biomedical research, genomic resources for the baboon, such as a quality annotated genome, are still lacking. To this end, we characterized the baboon kidney transcriptome using high-throughput cDNA sequencing (RNA-Seq) to identify genes, gene variants, single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (InDels), cellular functions, and key pathways in the baboon kidney to provide a genomic resource for the baboon. Analysis of our sequencing data revealed 45,499 high-confidence SNPs and 29,813 InDels comparing baboon cDNA sequences with the human hg18 reference assembly and identified 35,900 cDNAs in the baboon kidney, including 35,150 transcripts representing 15,369 genic genes that are novel for the baboon. Gene ontology analysis of our sequencing dataset also identified numerous biological functions and canonical pathways that were significant in the baboon kidney, including a large number of metabolic pathways that support known functions of the kidney. The results presented in this study catalogues the transcribed mRNAs, noncoding RNAs, and hypothetical proteins in the baboon kidney and establishes a genomic resource for scientists using the baboon as an experimental model.

Metabolic response to high-carbohydrate and low-carbohydrate meals in a nonhuman primate model

We established a model of chronic portal vein catheterization in an awake nonhuman primate to provide a comprehensive evaluation of the metabolic response to low-carbohydrate/high-fat (LCHF; 20% carbohydrate and 65% fat) and high-carbohydrate/low-fat (HCLF; 65% carbohydrate and 20% fat) meal ingestion. Each meal was given 1 wk apart to five young adult (7.8 ± 1.3 yr old) male baboons. A [U-¹³C]glucose tracer was added to the meal, and a [6,6-²H₂]glucose tracer was infused systemically to assess glucose kinetics. Plasma areas under the curve (AUCs) of glucose, insulin, and C-peptide in the femoral artery and of glucose and insulin in the portal vein were higher (P ≤ 0.05) after ingestion of the HCLF compared with the LCHF meal. Compared with the LCHF meal, the rate of appearance of ingested glucose into the portal vein and the systemic circulation was greater after the HCLF meal (P < 0.05). Endogenous glucose production decreased by ∼40% after ingestion of the HCLF meal but was not affected by the LCHF meal (P < 0.05). Portal vein blood flow increased (P < 0.001) to a similar extent after consumption of either meal. In conclusion, a LCHF diet causes minimal changes in the rate of glucose appearance in both portal and systemic circulations, does not affect the rate of endogenous glucose production, and causes minimal stimulation of C-peptide and insulin. These observations demonstrate that LCHF diets cause minimal perturbations in glucose homeostasis and pancreatic β-cell activity.

Renal histopathology of a baboon model with type 2 diabetes

Naturally occurring type 2 diabetes has been found in a colony of baboons. Ongoing characterization of the baboon colony maintained at the Southwest National Primate Research Center has revealed a significant range of glucose sensitivity with some animals clearly diabetic.   Seven baboons, four with diabetes and three without diabetes, underwent histopathological investigation. Three diabetic animals were diagnosed using fasting blood glucose, hemoglobin A1C, and intravenous glucose tolerance test, and a fourth one was known to have hyperglycemia. One control baboon and three baboons with diabetes had microalbuminuria. On kidney biopsy, diabetic baboons had thickening of the glomerular basement membrane and mesangial matrix expansion compared to controls. Immunohistochemistry showed the diabetic animals had increased mesangial expression of cellular fibronectin ED-A. Two diabetic animals with microalbuminuria had evidence of mesangiolysis with the formation of an early nodule. One diabetic animal had a Kimmestiel-Wilson nodule. We conclude that the baboon represents a useful primate model of diabetes and nephropathy that resembles the nephropathy associated with type 2 diabetes in humans.

Serum prostate specific antigen changes in cynomolgus monkeys (Macaca fascicularis) on a high sugar high fat diet

BACKGROUND

An inverse relationship between serum prostate specific antigen (PSA) levels and body mass index (BMI) has been reported in men but not in any animal model.

METHODS

Serum PSA in a colony of cynomolgus monkeys was assayed and correlated to body weight, prostate weight, and age. In addition, 15 animals were selected and fed a high sugar high fat (HSHF) diet for 49 weeks to increase their BMI and correlate it to PSA RESULTS: Serum PSA levels were positively correlated to prostate weight (r = 0.515, P = 0.025) and age (r = 0.548, P = 0.00072) but was not significantly correlated to body weight (r = -0.032, P = 0.419). For the animals on the HSHF diet, body weight, lean mass, fat mass, and BMI were significantly higher at 49 weeks than at baseline (P < 0.01). PSA was not significantly correlated to body weight and insulin at both baseline and 49 weeks. PSA was negatively correlated to BMI and insulin resistance (HOMA-IR) at 49 weeks but not at baseline. In addition, we observed hepatic steatosis and increases in serum liver enzymes.

CONCLUSIONS

Increases in BMI in cynomolgus monkeys as a result of consuming a HSHF diet resulted in PSA changes similar to those in humans with increased BMI. Cynomolgus monkeys are a useful model for investigating the relationship between obesity, diabetes, and PSA changes resulting from prostate gland pathology.

A custom rat and baboon hypertension gene array to compare experimental models

One challenge in understanding the polygenic disease of hypertension is elucidating the genes involved and defining responses to environmental factors. Many studies focus on animal models of hypertension; however, this does not necessarily extrapolate to humans. Current technology and cost limitations are prohibitive in fully evaluating hypertension within humans. Thus, we have designed a single-array platform that allows direct comparison of genes relevant to hypertension in animal models and non-human primates/human hypertension. The custom array is targeted to 328 genes known to be potentially related to blood pressure control. Studies compared gene expression in the kidney from normotensive rats and baboons. We found 74 genes expressed in both the rat and baboon kidney, 41 genes expressed in the rat kidney that were not detected in the baboon kidney and 34 genes expressed in the baboon kidney that were not detected in the rat kidney. To begin the evaluation of the array in a pathological condition, kidney gene expression was compared between the salt-sensitive deoxycorticosterone acetate (DOCA) rat model of hypertension and sham animals. Gene expression in the renal cortex and medulla from hypertensive DOCA compared with sham rats revealed three genes differentially expressed in the renal cortex: annexin A1 (up-regulated; relative intensity: 1.316 ± 0.321 versus 2.312 ± 0.283), glutamate-cysteine ligase (down-regulated; relative intensity: 3.738 ± 0.174 versus 2.645 ± 0.364) and glutathione-S transferase (down-regulated; relative intensity: 5.572 ± 0.246 versus 4.215 ± 0.411) and 21 genes differentially expressed in the renal medulla. Interestingly, few genes were differentially expressed in the kidney in the DOCA-salt model of hypertension; this may suggest that the complexity of hypertension may be the result of only a few gene-by-environment responsive events.

Androgen receptor CAG repeat polymorphism in males of six non-human primate species

BACKGROUND

Androgen receptor [CAG](n) microsatellite has been linked to human diseases.

METHODS

Six non-human primates were genotyped for the [CAG](n) microsatellite.

RESULTS

Marmosets and macaques are monomorphic, while mangabeys, baboons, and chimpanzees are polymorphic.

CONCLUSIONS

Non-human primates that are polymorphic for the microsatellite are candidate animal models for CAG-related diseases.

A preliminary report on the feeding of cynomolgus monkeys (Macaca fascicularis) with a high-sugar high-fat diet for 33 weeks

BACKGROUND

The metabolic syndrome is common in populations exposed to a typical Western diet. There is a lack of an animal model that mimics this condition.

METHODS

We fed 15 cynomolgus monkeys ad libitum a high-sugar high-fat (HSHF) diet for 33 weeks. Body weight, body composition, serum lipids, and insulin were measured at baseline and at 33 weeks.

RESULTS

The animals tolerated the HSHF diet very well. In the intervention group, total serum cholesterol and low-density lipoprotein cholesterol were 3- and 5-fold higher, respectively, at 33 weeks as compared with their baseline levels. Serum high-density lipoprotein cholesterol and triglycerides were not significantly affected. Dual-energy X-ray absorptiometry (DXA) analysis of the intervention group indicated that the trunk fat mass increased by 187% during this period.

CONCLUSIONS

Cynomolgus monkeys should be a useful model for investigating the interactions of diet and other factors such as genetics in the development of the metabolic syndrome.

Abstract 970: Effect of feeding a high fat, high simple carbohydrate diet on serum prostate specific antigen (PSA) in cynomolgus monkeys

Introduction

The prostate specific antigen (PSA) test is used for screening and monitoring of prostate cancer. However, PSA has clinical limitations as it is elevated in other pathological conditions other than prostate cancer. PSA is also influenced by other physiological and environmental variables like genetics and diet. The aim of this study was to investigate the effect of feeding a high fat, high simple carbohydrate (HFHSC) diet on serum PSA in a nonhuman primate species.

Methods

Fifteen cynomolgus monkeys (Macaca fascicularis) were fed an HFHSC diet for 4 months. Body weight and Dual energy X-ray absorptiometry (DEXA) measurements were done at 0, 8 and 16 weeks. Blood was also drawn from these animals and used to assay serum PSA and serum insulin levels.

Results 0 weeks Mean ± SD8 -weeks Mean ± SD16 weeks Mean ± SDP value (0-16) weeksBody weight (kg)5.48 ± 1.095.89 ± 1.355.99 ± 1.440.018Calorie intake (kcal/day)421.8 ± 115.20705.07 ± 101.52684.07 ± 102.361.7 × 10−8Tissue Fat (%)5.57 ± 3.817.29 ± 5.508.04 ± 6.70.155Region fat (%)5.33 ± 3.677 ± 5.237.7 ± 6.480.16Fat (g)289 ± 264.37412.07 ± 375.72467.6 ± 462.890.14Soft tissue mass (g)4860.53 ± 1105.735199.06 ± 1338.795269.33 ± 1435.430.0488Lean mass (g)4571.6 ± 968.114787 ±1125.334801.87 ± 1162.970.056Bone mineral content (g)228.44 ± 44.71234.71 ± 48.74236.85 ± 49.470.031PSA ng/ml0.70 ± 0.570.91 ± 0.460.96 ± 0.620.04Insulin µU/ml14.92 ± 12.1930.87 ± 26.1161.36 ± 66.290.014

Conclusions Feeding cynomolgus monkeys with an HFHSC diet for 4 months resulted in a significant increase in serum PSA levels. The mechanisms underlying this change in serum PSA is still under investigation, however, chronic hyper-insulinemia as indicated in this study might be one of the contributing factors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 970.

Change in salt intake affects blood pressure of chimpanzees: implications for human populations

BACKGROUND

Addition of up to 15.0 g/d salt to the diet of chimpanzees caused large rises in blood pressure, which reversed when the added salt was removed. Effects of more modest alterations to sodium intakes in chimpanzees, akin to current efforts to lower sodium intakes in the human population, are unknown.

METHODS AND RESULTS

Sodium intakes were altered among 17 chimpanzees in Franceville, Gabon, and 110 chimpanzees in Bastrop, Tex. In Gabon, chimpanzees had a biscuit diet of constant nutrient composition except that the sodium content was changed episodically over 3 years from 75 to 35 to 120 mmol/d. In Bastrop, animals were divided into 2 groups; 1 group continued on the standard diet of 250 mmol/d sodium for 2 years, and sodium intake was halved for the other group. Lower sodium intake was associated with lower systolic, diastolic, and mean arterial blood pressures in Gabon (2-tailed P<0.001, unadjusted and adjusted for age, sex, and baseline weight) and Bastrop (P<0.01, unadjusted; P=0.08 to 0.10, adjusted), with no threshold down to 35 mmol/d sodium. For systolic pressure, estimates were -12.7 mm Hg (95% confidence interval, -16.9 to -8.5, adjusted) per 100 mmol/d lower sodium in Gabon and -10.9 mm Hg (95% confidence interval, -18.9 to -2.9, unadjusted) and -5.7 mm Hg (95% confidence interval, -12.2 to 0.7, adjusted) for sodium intake lower by 122 mmol/d in Bastrop. Baseline systolic pressures higher by 10 mm Hg were associated with larger falls in systolic pressure by 4.3/2.9 mm Hg in Gabon/Bastrop per 100 mmol/d lower sodium.

CONCLUSIONS

These findings from an essentially single-variable experiment in the species closest to Homo sapiens with high intakes of calcium and potassium support intensified public health efforts to lower sodium intake in the human population.

Effect of 30 per cent maternal nutrient restriction from 0.16 to 0.5 gestation on fetal baboon kidney gene expression

Previous studies in rodents and sheep show that maternal nutrient restriction during pregnancy alters fetal renal development. To date, no studies using fetal baboon RNA with human Affymetrix gene chips have been published. In the present study we have (1) evaluated the specificity of the Affymetrix human gene array 'Laboratory on a Chip' system for use with fetal baboon mRNA and (2) investigated the effects of moderate maternal global nutrient restriction (NR; 70% of ad libitum animals) from early (30 days gestation (dG)) to mid-gestation (90 dG; term = 184 dG) on the fetal baboon kidney. Morphometric and blood measurements were made on 12 non-pregnant baboons before they were bred. All baboons were fed ad libitum until 30 days pregnant, at which time six control baboons continued to feed ad libitum (control - C) while six received 70% of the C diet on a weight adjusted basis. Fetal kidneys were collected following caesarean section at 90 dG, with samples flash frozen and fixed for histological assessment. Fetal hip circumference was decreased in the NR group (68 +/- 2 versus 75 +/- 2 mm), while fetal body weight and all other measurements of fetal size were not different between C and NR at 90 dG. Maternal body weight was decreased in the NR group (12.16 +/- 0.34 versus 13.73 +/- 0.55 kg). Having established the specificity of the Affymetrix system for fetal baboon mRNA, gene expression profiling of fetal kidneys in the context of our maternal nutrient restriction protocol shows that NR resulted in a down-regulation of genes in pathways related to RNA, DNA and protein biosynthesis, metabolism and catabolism. In contrast, genes in cell signal transduction, communication and transport pathways were up-regulated in the NR group. These changes indicate that even a moderate level of maternal global NR impacts fetal renal gene pathways. Our histological assessment of renal structure indicates decreased tubule density within the cortex of NR kidneys compared with controls. The number of glomerular cross-sections per unit area were unaffected by NR, suggesting that tubule tortuosity and/or tubule length was decreased in the NR kidney. Taken together the changes indicate that NR results in accelerated fetal renal differentiation. The negative impact of poor maternal nutrition on the fetal kidney may therefore be in part due to shortening of critical phases of renal growth resulting in decreased functional capacity in later life. These findings may have important implications for postnatal renal function, thereby contributing to the observed increased predisposition to hypertension and renal disease in the offspring of nutrient restricted mothers.

Effectiveness of recombinant soybean cysteine proteinase inhibitors against selected crop pests

Three recombinant soybean cysteine proteinase inhibitors (rSCPIs), L1, R1 and N2, were assessed for their potential to inhibit the growth and development of three major agricultural crop pests known to utilize digestive cysteine proteinases: Western corn rootworm (Diabrotica virgifera virgifera, WCR), Colorado potato beetle (Leptinotarsa decemlineata, CPB) and cowpea weevil (Callosobruchus maculatus, CW). In vitro experiments showed that cysteine proteinase activities in the crude gut extracts of the WCR, CPB, and CW were inhibited to various degrees by the three rSCPIs. Of the three rSCPIs tested, N2 was most effective in inhibiting the crude gut extract of WCR, CPB, and CW (50% inhibition at 5 x 10(-8), 5 x 10(-8), and 3 x 10(-7) M, respectively). The L1 was the least potent of the three CPIs tested, with 50% inhibition at 5 x 10(-6) M of the crude gut extracts of WCR. Results of in vivo experiments conducted to assess the effect of the three rSCPIs on the vital growth parameters of WCR, CPB and CW were consistent with results of the in vitro experiments.

Cowpea bruchid Callosobruchus maculatus uses a three-component strategy to overcome a plant defensive cysteine protease inhibitor

The soybean cysteine protease inhibitor, soyacystatin N (scN), negatively impacts growth and development of the cowpea bruchid, Callosobruchus maculatus[Koiwa et al. (1998) Plant J 14: 371-379]. However, the developmental delay and feeding inhibition caused by dietary scN occurred only during the early developmental stages (the 1st, 2nd and 3rd instars) of the cowpea bruchid. The 4th instar larvae reared on scN diet (adapted) exhibited rates of feeding and development which were comparable to those feeding on an scN-free diet (unadapted) prior to pupation. Total gut proteolytic capacity at this larval stage significantly increased in the scN-adapted insects. The elevated enzymatic activity was attributed to a differential expression of insect gut cysteine proteases (representing the major digestive enzymes), and of aspartic proteases. scN degradation by the gut extract was observed only in adapted bruchids, and this activity appeared to be a combined effect of scN-induced cysteine and aspartic proteases. Thirty cDNAs encoding cathepsin L-like cysteine proteases were isolated from insect guts, and they were differentially regulated by dietary scN. Our results suggest that the cowpea bruchid adapts to the challenge of scN by qualitative and quantitative remodelling of its digestive protease complement, and by activating scN-degrading protease activity.

Synergy between angiotensin and aldosterone in evoking sodium appetite in baboons

The synergy between ANG II and aldosterone (Aldo) in the induction of salt appetite, extensively studied in rats, has been tested in baboons. ANG II was infused intracerebroventricularly at 0.5 or 1.0 microg/h; Aldo was infused subcutaneously at 20 microg/h. Separate infusions over 7 days had no significant effect on the daily intake of 300 mM NaCl. Concurrent infusions, however, increased daily NaCl intake approximately 10-fold and daily water intake approximately 2.5-fold. In addition, the combined infusions caused 1) a reduction in daily food intake, 2) changes in blood composition indicative of increased vasopressin release, and 3) changes of urinary excretion rates of cortisol and Aldo indicative of increased ACTH release. Arterial blood pressure, measured in two baboons, rose during concurrent ANG II and Aldo treatment. These results indicate a potent synergy between central ANG II and peripheral Aldo in stimulating salt appetite in baboons. At the same time, other ANG II-specific brain mechanisms concerned with water intake, food intake, vasopressin release, ACTH release, and blood pressure regulation appear to have been activated by the same type of synergy. These central enhancement processes have never been previously demonstrated in primates.

Ingestive responses to administration of stress hormones in baboons

Experimental stress and the administration of the stress hormone ACTH have been reported to stimulate sodium appetite in many nonprimate species. Experiments were conducted to determine whether prolonged intracerebroventricular infusions of the neuropeptides corticotropin-releasing factor (CRF) and urocortin (Ucn), or systemic administration of ACTH, affected ingestive behaviors in a nonhuman primate, the baboon. Intracerebroventricular infusions of CRF or Ucn significantly decreased daily food intake. The decrease with Ucn continued into the postinfusion period. These infusions did not alter daily water intake. Daily voluntary intake of 300 mM NaCl solution was not increased, and there was evidence of reductions on days 2-4 of the infusions. Intramuscular injections of porcine ACTH or synthetic ACTH (Synacthen) for 5 days did not affect daily NaCl intake, although the doses were sufficient to increase cortisol secretion and arterial blood pressure. Sodium depletion by 3 days of furosemide injections did induce a characteristic sodium appetite in the same baboons. These results demonstrate the anorexigenic action of CRF and Ucn in this primate. Also, CRF, Ucn, and ACTH did not stimulate sodium appetite at the doses used.

Possible contribution of brain angiotensin III to ingestive behaviors in baboons

Recent experiments with specific aminopeptidase inhibitors in rats have strengthened earlier proposals that ANG III may be an important regulatory peptide in the brain. Central mechanisms regulating blood pressure, ingestive behaviors, and vasopressin release could be involved. Arguments in favor of a role for ANG III depend, in part, on the efficacy of ANG III as an agonist. These first studies in primates tested whether ANG III stimulates ingestive behaviors in baboons. Intracerebroventricular (ICV) infusions of ANG III were as potent as ANG II in stimulating water drinking and intake of NaCl solution. On the basis of this criterion and consistent with findings in rats, ANG III could be a main effector peptide in the regulation of ingestive behaviors in a primate.

Phage display selection of hairpin loop soyacystatin variants that mediate high affinity inhibition of a cysteine proteinase

Two hairpin-loop domains in cystatin family proteinase inhibitors form an interface surface region that slots into the active site cleft of papain-like cysteine proteinases, and determine binding affinity. The slot region surface architecture of the soybean cysteine proteinase inhibitor (soyacystatin N, scN) was engineered using techniques of in vitro molecular evolution to define residues that facilitate interaction with the proteinase cleft and modulate inhibitor affinity and function. Combinatorial phage display libraries of scN variants that contain mutations in the essential motifs of the first (QVVAG) and second (EW) hairpin-loop regions were constructed. Approximately 1010-1011 phages expressing recombinant scN proteins were subjected to biopanning selection based on binding affinity to immobilized papain. The QVVAG motif in the first hairpin loop was invariant in all functional scN proteins. All selected variants (30) had W79 in the second hairpin-loop motif, but there was diversity for hydrophobic and basic amino acids in residue 78. Kinetic analysis of isolated scN variants identified a novel scN isoform scN(LW) with higher papain affinity than the wild-type molecule. The variant contained an E78L substitution and had a twofold lower Ki (2.1 pM) than parental scN, due to its increased association rate constant (2.6 +/- 0.09 x 107 M-1sec-1). These results define residues in the first and second hairpin-loop regions which are essential for optimal interaction between phytocystatins and papain, a prototypical cysteine proteinase. Furthermore, the isolated variants are a biochemical platform for further integration of mutations to optimize cystatin affinity for specific biological targets.

Sodium-lithium countertransport activity is linked to chromosome 5 in baboons

The genes involved in the regulation of cellular sodium transport characteristics, which are correlated with some forms of essential hypertension, have not yet been identified. We are studying the genes and environmental factors that affect red blood cell sodium-lithium countertransport (SLC) activity and intracellular sodium (ICNa) concentration in 634 baboons that comprise 11 pedigrees of 2 and 3 generations each. To detect and locate possible quantitative trait loci (QTLs) that affect SLC activity and ICNa concentration, we performed a genome screen by using a maximum likelihood-based variance-components linkage analysis program (SOLAR). SLC and ICNa phenotypes as well as genotypes on 281 microsatellite loci were available for all pedigreed animals. Both SLC and ICNa traits were highly heritable (residual heritability 0.593+/-0.083 [P<0.0001] and 0.739+/-0.082 [P<0.0001], respectively). We obtained evidence that a possible QTL for SLC activity is located on the baboon homologue of human chromosome 4 between D4S2456 and D4S2365 with a maximum multipoint lod score of 9.3 (P<10(-)(10)) near D4S1645. This QTL accounts for approximately two thirds of the total additive genetic variation in SLC activity in baboons. Although ICNa concentration was highly heritable, we found no evidence for linkage to a QTL with use of this methodology. Thus, we have evidence that a gene located on the baboon homologue of human chromosome 4 (baboon chromosome 5) affects cell sodium transport in baboons.

A Quantitative Trait Locus for Sodium-Lithium Countertransport Is Linked to Chromosome Four in Baboons

P134

Alterations in cell sodium transport characteristics, such as red blood cell intracellular sodium (ICNa) levels and sodium-lithium countertransport (SLC), are secondary biochemical indices of a primary cell membrane abnormality that have been associated with some forms of essential hypertension. We are studying the effects of genes and environmental factors on hypertension and blood pressure-related phenotypes such as ICNa and SLC in baboons, a non-human primate model for blood pressure regulation. In a previous study of 84 baboons, systolic blood pressure increased with increasing ICNa (p = 0.002) and SLC (p = 0.06). In the current study, genotypes for 280 microsatellite loci, as well as SLC and ICNa data, were determined for 623 baboons comprising 11 pedigrees. The heritabilities of ICNa and SLC were 0.80±0.07 and 0.61±0.10, respectively. We performed a genome screen using a maximum-likelihood based, variance components linkage analysis program (SOLAR) and obtained evidence that a possible quantitative trait locus (QTL) for SLC is located on the baboon homologue of human chromosome 4 between D4S2456 and D4S2365 with a maximum multipoint lod-score = 8.76 (p< 10 -10 ) at D4S1645. This QTL accounts for approximately 2/3 of the additive genetic variation in SLC in baboons. We found no evidence for linkage with ICNa. Thus, we have evidence that a gene located on human chromosome 4 (baboon chromosome 5) affects cell sodium transport in baboons. No strong candidate genes have yet been identified in this region. However, future studies to identify and characterize this gene may elucidate fundamental processes that contribute to the development of hypertension.

A plant defensive cystatin (soyacystatin) targets cathepsin L-like digestive cysteine proteinases (DvCALs) in the larval midgut of western corn rootworm (Diabrotica virgifera virgifera)

Feeding bioassay results established that the soybean cysteine proteinase inhibitor N (soyacystatin N, scN) substantially inhibits growth and development of western corn rootworm (WCR), by attenuating digestive proteolysis [Zhao, Y. et al. (1996) Plant Physiol. 111, 1299-1306]. Recombinant scN was more inhibitory than the potent and broad specificity cysteine proteinase inhibitor E-64. WCR digestive proteolytic activity was separated by mildly denaturing SDS-PAGE into two fractions and in-gel assays confirmed that the proteinase activities of each were largely scN-sensitive. Since binding affinity to the target proteinase [Koiwa, H. et al. (1998) Plant J. 14, 371-380] governs the effectiveness of scN as a proteinase inhibitor and an insecticide, five peptides (28-33 kDa) were isolated from WCR gut extracts by scN affinity chromatographic separation. Analysis of the N-terminal sequence of these peptides revealed similarity to a cathepsin L-like cysteine proteinase (DvCAL1, Diabrotica virgifera virgifera cathepsin L) encoded by a WCR cDNA. Our results indicate that cathepsin L orthologs are pivotal digestive proteinases of WCR larvae, and are targets of plant defensive cystatins (phytocystatins), like scN.

Carbohydrate binding and resistance to proteolysis control insecticidal activity of Griffonia simplicifolia lectin II

Griffonia simplicifolia leaf lectin II (GSII), a plant defense protein against certain insects, consists of an N-acetylglucosamine (GlcNAc)-binding large subunit with a small subunit having sequence homology to class III chitinases. Much of the insecticidal activity of GSII is attributable to the large lectin subunit, because bacterially expressed recombinant large subunit (rGSII) inhibited growth and development of the cowpea bruchid, Callosobruchus maculatus (F). Site-specific mutations were introduced into rGSII to generate proteins with altered GlcNAc binding, and the different rGSII proteins were evaluated for insecticidal activity when added to the diet of the cowpea bruchid. At pH 5.5, close to the physiological pH of the cowpea bruchid midgut lumen, rGSII recombinant proteins were categorized as having high (rGSII, rGSII-Y134F, and rGSII-N196D mutant proteins), low (rGSII-N136D), or no (rGSII-D88N, rGSII-Y134G, rGSII-Y134D, and rGSII-N136Q) GlcNAc-binding activity. Insecticidal activity of the recombinant proteins correlated with their GlcNAc-binding activity. Furthermore, insecticidal activity correlated with the resistance to proteolytic degradation by cowpea bruchid midgut extracts and with GlcNAc-specific binding to the insect digestive tract. Together, these results establish that insecticidal activity of GSII is functionally linked to carbohydrate binding, presumably to the midgut epithelium or the peritrophic matrix, and to biochemical stability of the protein to digestive proteolysis.

Evidence that brain angiotensin II is involved in both thirst and sodium appetite in baboons

The roles of ANG II in the brain mechanisms subserving thirst and Na appetite in baboons were investigated by chronic intracerebroventricular infusions of ANG II and AT1-receptor antagonists using subcutaneous miniosmotic pumps and by oral administration of captopril. ANG II at 3 or 5 micrograms/h for 7 days increased water intake from 2,455 +/- 107 to 7,052 +/- 562 ml/day by day 6 and 300 mM NaCl intake from 8.3 +/- 1.1 to 275 +/- 87 mmol/day by day 5. Concurrent intracerebroventricular losartan (300 micrograms/h) did not substantially reduce these responses, but they were abolished by intracerebroventricular ZD-7155 (50 micrograms/h). The increase of 300 mM NaCl intake when it was offered after intramuscular injection of furosemide, 2 mg . kg-1 . day-1 for 3 days, was unaltered by intracerebroventricular losartan (300 micrograms/h) but was reduced by intracerebroventricular ZD-7155 (50 micrograms/h) infused throughout Na depletion/repletion; oral captopril (1 g, 3 and 18 h before access to 300 mM NaCl) also reduced NaCl intake. Restriction of water intake to 25% of daily intake for 3 days caused a high intake of water on day 4, and this was reduced by intracerebroventricular losartan (300 micrograms/h) infused throughout the period of water restriction/rehydration. These novel results in a primate species suggest that brain ANG II is involved in both thirst and Na appetite, acting via AT1 receptors.

Phage display selection can differentiate insecticidal activity of soybean cystatins

Plant cysteine proteinase inhibitors (phytocystatins) have been implicated as defensive molecules against Coleopteran and Hemipteran insect pests. Two soybean cystatins, soyacystatin N (scN) and soyacystatin L (scL), have 70% sequence identity but scN is a much more potent inhibitor of papain, vicilin peptidohydrolase and insect gut proteinases. When these cystatins were displayed on phage particles, papain-binding affinity and CPI activity of scN were substantially greater than those of scL, in direct correlation with their relative CPI activity as soluble recombinant proteins. Furthermore, scN substantially delayed cowpea weevil (Callosobruchus maculatus (F.)) growth and development in insect feeding bioassays, whereas scL was essentially inactive as an insecticide. Papain biopanning selection of phage-displayed soyacystatins resulted in a 200-1000-fold greater enrichment for scN relative to scL. These results establish that binding affinity of cystatins can be used in phage display biopanning procedures to select variants with greater insecticidal activity, illustrating the potential of phage display and biopanning selection for directed molecular evolution of biological activity of these plant defensive proteins.

Linkage of essential hypertension to the angiotensinogen locus in Mexican Americans

Essential hypertension has been linked to a highly polymorphic marker at the angiotensinogen locus, and association with a polymorphism in this locus has been found in some populations. We tested the hypothesis that these same polymorphic markers are linked to essential hypertension in Mexican Americans. The data comprised all the affected relative pairs in 46 extended families chosen at random from a low-income barrio in San Antonio. Specifically, we searched for linkage by testing for excessive marker alleles shared identical by descent (IBD) among hypertensive relative pairs. When women taking oral contraceptives or hormones were excluded, the affected relative pairs shared a significant excess of alleles IBD for the highly heterozygous GT repeat polymorphism (P=.038) and were marginally significant for the M235T variant (P=.079), which has a much lower heterozygosity (0.43 versus 0.85 for the GT repeat). We also assayed plasma levels of angiotensinogen and, using likelihood methods, found no significant association (P=.43) between plasma levels of angiotensinogen and M235T genotypes. These results support the linkage of essential hypertension to the angiotensinogen locus but do not indicate a specific role for the M235T variant.

An insecticidal N-acetylglucosamine-specific lectin gene from Griffonia simplicifolia (Leguminosae)

Griffonia simplicifolia II, an N-acetylglucosamine-specific legume lectin, has insecticidal activity when fed to the cowpea weevil, Callosobruchus maculatus (F.). A cDNA clone encoding G. simplicifolia II was isolated from a leaf cDNA library, sequenced, and expressed in a bacterial expression system. The recombinant protein exhibited N-acetylglucosamine-binding and insecticidal activity against cowpea weevil, indicating that glycosylation and multimeric structure are not required for these properties. These results support the hypothesis that genes of the legume lectin gene family encode proteins that function in plant defense against herbivores.

Training adaptations of baboons to light and moderate treadmill exercise

We evaluated training adaptations by 18 baboons (Papio cynocephalus anubis) to low and moderate quadrupedal walking exercise on a motorized treadmill. Moderate training produced 47% increases in lactate threshold, 63% increases in muscle citrate synthetase activity, increases in percentage of Type IIc muscle fibers, and reduced plasma insulin concentrations. Low training produced only reduced plasma insulin concentrations. Only results indicate that the baboon response to exercise training was similar to that of Homo sapiens, and dependent on exercise intensity.

Selective breeding to develop lines of baboons with high and low blood pressure

Lines of baboons with high and low blood pressure were developed by selective breeding. Blood pressure was measured in 456 adult feral baboons under ketamine immobilization by direct arterial cannulation. Males with blood pressures two standard deviations and females with blood pressures one standard deviation above and below the cumulative mean were selected as progenitors. High males were mated with high females and low males were mated with low females. We measured blood pressure and plasma renin activity on 100 progeny, 54 males and 46 females, greater than 44 months of age with an abbreviated tether protocol and software program for data collection. Mean systolic and diastolic nighttime pressures for the high line were 126/72 and for the low line were 114/65 mm Hg. Line differences for systolic (12 mm Hg) and for diastolic (7 mm Hg) pressures were significant (p < 0.001). The line difference for plasma renin activity (1.1 [ng/mL]/hr) was not significant. Progeny pressures ranged from 84/49 to 191/126 mm Hg. There was no sex effect on blood pressure or plasma renin activity line differences. Heritability of systolic pressure was 0.46 +/- 0.19 and of diastolic pressure was 0.32 +/- 0.19. These results indicate that, by selective breeding and rigorous measurement of blood pressure, lines of baboons with significant difference in blood pressure can be developed.

Alpha-amylase inhibitor, not phytohemagglutinin, explains resistance of common bean seeds to cowpea weevil

There are claims that phytohemagglutinin (PHA), the lectin of common bean, Phaseolus vulgaris, is toxic when fed to the cowpea weevil, Callosobruchus maculatus, and that PHA serves as the chemical defense against this seed-feeding bruchid beetle (DH Janzen, HB Juster, IE Liener [1976] Science 192: 795-796; AMR Gatehouse, FM Dewey, J Dove, KA Fenton, A Pusztai [1984] J Sci Food Agric 35: 373-380). However, our studies indicate that neither PHA nor its isolectins have detrimental effects when fed to the cowpea weevil. To explain these contradictory results we characterized the commercial lectin source used by A. M. R. Gatehouse, F. M. Dewey, J. Dove, K. A. Fenton, A. Pusztai (1984, J Sci Food Agric 35: 373-380). We demonstrate here that the toxic effects of PHA to cowpea weevil are due to an alpha-amylase inhibitor contaminant in the commercial preparation.