Normal Baboon Research Articles

Increased salt sensitivity in offspring of pregnancies complicated by experimental preeclampsia.

Preeclampsia is a hypertensive disorder of pregnancy known to increase the risk of cardiovascular disease in mothers and offspring. Offspring exposed to a suboptimal intrauterine environment may experience altered fetal programming and subsequent long-term cardiovascular changes. This study investigated changes in the vascular response in offspring from experimental preeclampsia (EPE) induced by uterine artery ligation, in the absence of fetal growth restriction, compared to normal baboon pregnancies (controls), following a high salt diet challenge. After 1week of standard diet (containing <1% salt), animals were fed a high salt diet (6%) for 2weeks. Systolic and diastolic blood pressure (SBP, DBP), aldosterone, renin and creatinine clearance were evaluated in EPE (n=6, 50% male) and control (n=6, 50% male) offspring. A repeated measures analysis was performed, and P<0.05 was considered significant. At baseline, there were no differences between the groups in any parameter (EPE, mean age and weight 3.2±1.2years, 6.8±1.0kg, respectively; Control, 2.9±0.8years, 7.1±1.5kg). After salt loading the EPE group had significantly higher SBP (92±5mmHg) compared to the control group (83±4mmHg, P=0.03). Aldosterone concentration was higher in the EPE group despite the same salt excretion and no difference in renal function. Salt sensitivity may differ in offspring from hypertensive pregnancies due to fetal programming. This could have long-term consequences for cardiovascular health of EPE offspring and further research is required to determine the exact pathological mechanisms.

Derivation and Characterization of Novel Nonhuman Primate Embryonic Stem Cell Lines from In Vitro-Fertilized Baboon Preimplantation Embryos

The development of nonhuman primate (NHP) embryonic stem cell (ESC) models holds great promise for cell-mediated treatment of debilitating diseases and to address numerous unanswered questions regarding the therapeutic efficacy of ESCs while supplanting ethical considerations involved with human studies. Here we report successful establishment and characterization of 3 novel baboon (Papio cynocephalus) ESC lines from the inner cell mass of intracytoplasmic sperm injection-derived blastocysts. Embryos were cultured in an improved baboon embryo in vitro culture protocol. The inner cell mass of blastocyst was laser-dissected and plated on mouse embryonic fibroblast feeder cell monolayer in the NHP ESC culture medium. Three cell lines with characteristic ESC morphology have been cultured through an extended period (>14 months), with 2 male cell lines (UT-1 and -2) and 1 female cell line (UT-3) displaying normal baboon karyotypes. Reverse transcription-polymerase chain reaction analysis confirmed that all 3 lines express primate ESC pluripotency markers, including OCT-4, NANOG, SOX-2, TERT, TDGF, LEFTYA, and REX-1. All 3 lines demonstrated positive immunocytochemical staining for OCT-4, stage-specific embryonic antigen-3, stage-specific embryonic antigen-4, TRA-1-60, and TRA-1-81. Baboon ESCs injected into NOD/SCID mice formed teratomas with all 3 germ layers. In addition, embryoid body-like spherical structures were derived and initial outgrowth was observed when embedded into extracellular matrix Matrigel. The ESC lines established in this NHP model have the potential to extend our knowledge in the fields of developmental biology, regenerative medicine, and future applications, including preclinical safety assessment of in vivo stem cell therapy.

만성 폐질환인 폐이형성증을 보이는 baboon 폐조직에 Dendritic-like cell의 축적

본 연구에서 정상적인 baboon의 흉선조직 및 폐조직에서 HLA-DR과 PGP9.5항원에 대한 반응성을 나타내는 수지상세포 형태의 세포가 축적되는 것을 보았다. 하지만, 이런 세포들은 baboon 이 BPD즉 폐이형성증에 걸리게 되면 사라진다는 것을 확인하였다. 그리고 140일 제태기간보다 125일 제태 기간을 보낸 미성숙 baboon이 HLA-DR을 가지는 세포가 더 많아 진다는 것을 관찰할 수 있었고 이로 인해 BPD동물모델을 구축하는데 125일 제태 기간을 보낸 동물이 훨씬 적합하다는 것을 알았다. 또한 bombesin의 항체인 2A11을 처리한 baboon (125d-14d/PRN)의 폐조직에서는 정상수준의 HLA-DR positive세포들이 관찰되었다. 더욱이, Baboon의 흉선으로부터 분리한 thymocyte로 bombesin에 대한 chemotaxis를 수행한 결과 세포이동 반응성을 보였다. 이러한 결과들은 생체 내 BLP들을 차단하면 BPD에 의해 야기된 폐이형성증을 막을 수 있고 2A11항체가 수동 면역제로 폐이형성증을 치료할 수 있는 치료제로써의 가능성을 제시하는 것이다. The present investigation demonstrates HLA-DR and PGP9.5 double positive cells accumulate thymus cortical region in normal baboon thymus and baboon lung. But, these cells disappeared in thymus and lung of bronchopulmonary dysplasia (BPD) animals. 125d GC animal model is more suitable for BPD than 140d GC animal. Anti-bombesin antibody, 2A11 treated baboon recover normal level of HLA-DR positive cells from BPD animal. In addition, thymocytes show responsiveness for bombesin. These observation suggest that blocking BLPs protects a chronic lung injury by BPD and 2A11 is possible agent for passive therapy of BPD.

Abstract 2106: Quantification of Doppler Flow Velocity-Derived Pulmonary Flow Reserve in Healthy Primates

Background: Pulmonary vascular disease (PVD), characterized by progressive pulmonary microvascular destruction, is only clinically evident late in its course when pulmonary artery pressure (PAP) rises. We hypothesized that changes in pulmonary flow reserve (PFR, maximal hyperemic vs. basal flow) may precede the PAP rise and thus aimed to: validate invasively-measured Doppler flow-velocity (v dopp ) as a marker of pulmonary blood flow and define the optimal hyperemic agent and dose for v dopp -derived PFR (PFR dopp ) assessment, in healthy baboons. Methods: Eight baboons were anaesthetized and a Doppler-sensing guidewire (DSG) placed in a segmental pulmonary artery. Angiographically-determined vessel diameter ( D ) and DSG-measured v dopp were obtained at baseline and at increasing intrapulmonary normal saline (NS) infusion rates and boluses. Escalating local doses of adenosine, acetylcholine &amp; papaverine were administered, v dopp obtained and PFR dopp calculated. Results: NS administration did not change D or v dopp (panels A &amp; B, p≥0.4). Adenosine produced a dose-dependent increase in v dopp maximal at 200μg/kg/min (p&lt;0.0001, panel C), papaverine to 24mg significantly increased v dopp (p&lt;0.0001, panel D) but acetylcholine to 10 − l concentration reduced v dopp (p=0.0008). Adenosine and papaverine-derived PFR dopp values were 1.5–2.0. Conclusions: As D does not vary with NS or hyperemic agent administration, v dopp is a valid marker of pulmonary blood flow. Adenosine and papaverine can be used with a Doppler-flow wire to derive PFR, with normal baboon PFR dopp being 1.5 – 2.0. Thus PFR dopp may be a potential novel marker for investigating early PVD.

Ontogeny of hematological cell and biochemical profiles in maternal and fetal baboons (Papio species)

The normal ranges of hematological cell profiles and biochemistry are documented in adult non-pregnant, pregnant, juvenile, and neonatal baboons. Despite the extensive use of the baboon as a model for the study of various aspects of pregnancy, there is no data from paired mothers and their fetuses at different stages of gestation. Hematologic and biochemical profile data were obtained from eight non-pregnant female baboons, 37 mothers and 38 fetal baboons at 30 +/- 2, 90 +/- 2, 125 +/- 2, and 175 +/- 2 days of gestation (mean +/- range; dGA; term, 180 dGA). Changes observed in fetal and maternal blood during normal baboon pregnancy were similar to those reported in human pregnancy. The level of alkaline phosphatase was two times higher in fetal blood circulation than that reported in human pregnancy.

Localization of human ATP-binding cassette transporter 1 (ABC1) in normal and atherosclerotic tissues.

The present study examines the expression of ATP-binding cassette transporter 1 (ABC1) mRNA in normal and atherosclerotic tissues by using in situ hybridization in an effort to better understand the function of this cholesterol transport protein. Samples of normal baboon tissues as well as human normal and atherosclerotic aortas were hybridized with (35)S-labeled ABC1 sense and antisense riboprobes. Widespread expression of ABC1 was observed generally in tissues containing inflammatory cells and lymphocytes. Other noninflammatory cells that were also sites of ABC1 synthesis included the ductal cells of the kidney medulla, Leydig cells in the testis, and glial cells in the baboon cerebellum. Although normal veins and arteries did not express ABC1 mRNA, it was found to be upregulated in the setting of atherosclerosis, where widespread expression was found in macrophages within atherosclerotic lesions. These results are consistent with the proposed role of ABC1 in cholesterol transport in inflammatory cells. The specific upregulation of ABC1 mRNA in the setting of atherosclerosis probably reflects the response of leukocytes to cholesterol loading. However, the presence of ABC1 in ductal cells of the kidney medulla and in the small intestine suggest a more general role for this protein in cholesterol transport in other cell types.

Ezrin, a membrane-organizing protein, as a polarization marker of the retinal pigment epithelium in vertebrates.

Immunoreactivity for ezrin, a membrane-organizing phosphoprotein that tethers actin microfilaments to cell membrane proteins, was evaluated as a polarization marker in the intraocular neuroepithelial cells of vertebrates, especially in the retinal pigment epithelium (RPE). Six fetal human eyes representing the 14th-28th gestational weeks, 9 normal adult eyes, 12 eyes with intraocular tumors, and 26 eyes from 15 other vertebrate species were analyzed by immunohistochemistry using the avidin-biotinylated peroxidase complex (ABC) method and monoclonal antibody (mAb) 3C12 to ezrin. The apical cytoplasm and microvilli of the human RPE always reacted with mAb 3C12, but the basal cytoplasm was labeled in reactive RPE only. In autopsy eyes and if fixation was delayed, ezrin immunoreactivity in RPE was more diffuse. Developing RPE became gradually immunoreactive from the 14th week of gestation onward. The microvilli of the baboon, pig, raccoon dog, cow, and rat RPE cells were likewise labeled, and their basal cytoplasm was variably immunoreactive as well, but the microvilli of the avian RPE did not react with the antibody used. In all six mammals mentioned, both layers of the ciliary epithelium and the anterior iris epithelium reacted for ezrin, and the posterior epithelium was weakly labeled in pig, cow, and rat eyes. Normal peripheral and reactive human retina, and normal baboon, pig, raccoon dog, cow, rat, black grouse, and jay eyes, showed immunoreaction for ezrin in Muller cells, usually in their microvilli. Ezrin is widely found in RPE and anterior segment neuroepithelia of the mammalian eye, in which it may segregate membrane proteins to specific membrane surfaces, especially to the apical microvilli of the RPE, which intimately interact with outer segments of photoreceptor cells. The ezrin gene on human chromosome 6q25-26 is consequently a candidate gene for causing retinal degenerations.

Synthesis, biological evaluation, and baboon PET imaging of the potential adrenal imaging agent cholesteryl- p-[ 18f]fluorobenzoate

ABSTRACT. Cholesteryl- p-[ 18F]fluorobenzoate ([ 18F]CFB) was investigated as a potential adrenal positron emission tomography (PET) imaging agent for the diagnostic imaging of adrenal disorders. We describe the synthesis, biodistribution, adrenal autoradiography, and baboon PET imaging of [ 18F]CFB. The synthesis of [ 18F]CFB was facilitated by the use of a specially designed microwave cavity that was instrumental in effecting 70–83% incorporation of fluorine-18 in 60 s via [ 18F]fluoro-for-nitro exchange. Tissue distribution studies in mature female Sprague–Dawley rats showed good accumulation of [ 18F]CFB in the steroid-secreting tissues, adrenals and ovaries, at 1 h postinjection. The effectiveness of [ 18F]CFB to accumulate in diseased adrenals was shown through biodistribution studies in hypolipidemic rats, which showed a greater than threefold increase in adrenal uptake at 1 h and increased adrenal/liver and adrenal/kidney ratios. Analysis of the metabolites at 1 h in the blood, adrenals, spleen, and ovaries of hypolipidemic and control rats showed the intact tracer representing greater than 86%, 93%, 92%, and 82% of the accumulated activity, respectively. [ 18F]CFB was confirmed to selectively accumulate in the adrenal cortex versus the adrenal medulla by autoradiography. Normal baboon PET imaging with [ 18F]CFB effectively showed adrenal localization as early as 15 min after injection of the tracer, with enhanced adrenal contrast seen at 60–70 min. These results suggest that [ 18F]CFB may be useful as an adrenal PET imaging agent for assessing adrenal disorders.

Characterization of antigens expressed in normal baboon trophoblast and cross-reactive with HIV/SIV antibodies

Electron microscopic studies have revealed the presence of endogenous retroviral (ERV) particles in normal primate placental tissues. These particles have ultrastructural similarities to type C retroviral particles and are mainly associated with the trophoblast. In normal human placental tissues, they have antigenic similarity with exogenous retroviruses, such as the human immunodeficiency virus (HIV), and may have a role to play in the regulation of cellular gene expression, syncytiotrophoblast formation or pregnancy-related immunosuppression. In this study, a panel of antibodies (polyclonal and monoclonal antibodies) against viral proteins (anti-HIV and anti-SIV) and endogenous retroviral (ERV) proteins were assessed by immunohistochemistry and immunoblotting, for their cross-reactivity with ERV particles isolated from normal baboon placental tissues. The antibodies (anti-HERV-K RT, anti-ERV3 env, anti-HIV-1 p17, anti-HIV-2 gp120) reacted positively with the syncytiotrophoblast and each antibody recognized one or two proteins of molecular weights (MW) 38, 58 or 64 kDa present in the baboon placental villous tissues and SIV-infected molt-4 Cl 8 cells, but not in uninfected cells. The results of this study confirm the specific expression of retroviral cross-reactive antigens in normal baboon placental tissues and suggest placental cellular proteins may have antigenic similarity with those recognized by anti-HIV/SIV antibodies. The role of these retroviral-related proteins expressed at the maternal–fetal interface remain unclear.

Immunohistochemical localization of retroviral-related antigens expressed in normal baboon placental villous tissue.

Endogenous retroviral particles (ERVs) have been detected in the genome of all eukaryotes. They are generally non-pathogenic except in mice where they have been found to induce tumors and immunological disorders. The ERVs have morphological features consistent with type-C retroviral particles and are commonly expressed in normal placental villous tissues. ERVs may have a role in the regulation of placental gene expression, syncytiotrophoblast formation, or pregnancy-related immunosuppression. In this study, well-characterized antibodies (monoclonal and polyclonal antibodies) raised against retroviral proteins (anti-HIV and anti-SIV) and endogenous retroviral (ERV) particles were assessed for their cross-reactivity (by using immunohistochemistry) with normal baboon placental and other adult tissues. The monoclonal antibodies to exogenous retroviral proteins (anti-HIV-2 gp120, anti-HIV-1 gp41, anti-SIVmac p27, anti-HIV-1 RT, and anti-HIV-2 core protein) showed specific immunohistochemical reactivity with the syncytiotrophoblast. Antibodies to endogenous retroviral gene products (anti-ERV3 env, anti-HERV-K RT, and anti-HERV-K env) also reacted in a similar manner and did not cross-react with other adult tissues. These studies have shown that retroviral-cross-reactive proteins are expressed in baboon placental syncytiotrophoblast and may have a role to play at the feto-maternal interface.

Characterization of HIV/SIV cross-reactive antigens expressed in normal baboon placental villous tissue

The LG HIV Ag–Ab Plus, a new fourth generation diagnostic assay for HIV infection, was evaluated in comparison to the Enzygnost HIV Integral, an established fourth generation HIV assay. The LG assay showed 100% sensitivity with 109 samples with anti-HIV-1, anti-HIV-2 or anti-HIV-1 group O reactivity. It also detected correctly all 51 positives on three BBI performance panels, slightly outperforming the Enzygnost HIV Integral, which detected 50. The specificity of the LG HIV Ag–Ab Plus was 99.9% with 999 sera from healthy blood donors, which was slightly inferior to the performance of the Enzygnost HIV Integral, which had 100% specificity. The LG assay showed 100% specificity with 81 specimens with underlying diseases including hepatitis B, demonstrating a low risk of cross-reactivity with other infections. The reduction of the diagnostic window by the LG HIV Ag–Ab Plus, compared to a third generation HIV assay, was 6.3 days. The LG assay also showed sufficiently high intra-person and inter-person reproducibility. The overall performance of this new fourth generation HIV assay was adequate for screening and diagnosis of HIV infection.

Evaluation of samarium-153 and holmium-166-EDTMP in the normal baboon model

Bone-seeking radiopharmaceuticals such as ethylenediaminetetramethylene phosphonate (EDTMP) complexes of samarium-153 and holmium-166 are receiving considerable attention for therapeutic treatment of bone metastases. In this study, using the baboon experimental model, multicompartmental analysis revealed that with regard to pharmacokinetics, biodistribution, and skeletal localisation, 166Ho-EDTMP was significantly inferior to 153Sm-EDTMP and 99mTc-MDP. A more suitable 166Ho-bone-seeking agent should thus be sought for closer similarity to 153Sm-EDTMP to exploit fully the therapeutic potential of its shorter half-life and more energetic beta radiation.

A new method of monitoring motor activity in baboons

Movement activity of a normal baboon and of a baboon with induced Parkinsonism by unilateral administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was recorded by the Walter Reed Activity Monitor (or actigraph). Mean activity in the lesioned baboon was 41% less than that of the nonlesioned baboon measured over a 14-day period. In addition, the daily maximum activity value was significantly less in the MPTP-treated baboon. Moreover, resting and sleeping periods were 30% greater in the lesioned animal. The akinesia and resting and sleeping periods were displayed by the lesioned baboon throughout the day, whereas the control baboon showed them only at night. The data representing summarized movement activity are in accordance with observations of bradykinesia, hypokinesia, and akinesia of the MPTP-treated baboon. The actigraph was well tolerated by the animal because its small size and weight made it largely unobtrusive. We suggest that the actigraph is an appropriate device for measuring motor activity in nonhuman primates.

Characterisation of endogenous retroviral antigens expressed in normal baboon and human placental tissues

Characterisation of endogenous retroviral antigens expressed in normal baboon and human placental tissues

Progressive alveolar septal injury in primates exposed to 60% oxygen for 14 days

Moderate exposures to hyperoxia are becoming increasingly common in clinical medicine as advancing technology allows O2 to be more effectively delivered to nonintubated patients. The sensitivity of the lung to injury by a subchronic exposure to 60% O2 was investigated, using baboons and serial lobar biopsies. Because results obtained from different regions of the lung were compared, the alveolar architecture of different lung lobes of three controls was studied, with the use of electron microscopic morphometric analyses, to assess possible lobar differences in volume, surface, and numerical densities of cells and tissues. In animals exposed to 60% O2, the same techniques were used to assess specific tissue changes in the epithelial, interstitial, and endothelial compartments of the alveolar septa. All six lobes of the normal baboon lung were found to be identical with respect to alveolar architecture. Thus, for gases of low reactivity and given in high concentrations, such as O2, cross-comparisons between different lobes are appropriate. Exposure to 60% O2 was found to cause proliferation of alveolar type II epithelium, suggesting a low-grade, chronic epithelial injury. Animals allowed to recover for 8 wk in room air showed progressive changes in the alveolar interstitium, involving increases in both cells and matrix. Because sequential lobar resections were done, animals were exposed both to 60% O2 and to the effects of general anesthesia and thoracotomies. The exposure to 60% O2 for 2 wk in this experimental setting leads to an alveolar septal injury that includes a progressive interstitial fibrotic response.

Biodistribution and accumulation in inflammatory lesions of different thiol reduction-mediated 99Tcm-IgG preparations in baboon models

The diagnostic efficacy of 99Tcm-labelled non-specific polyclonal immunoglobulin (IgG) as tracer for abdominal inflammatory lesions is impeded by its unfavourable physiological organ distribution patterns. Modifications to the IgG molecules during preparation and labelling may alter its in vivo behaviour and accumulation in inflammatory foci. This report describes scintigraphic biodistribution studies in the baboon (normal and with inflammatory lesions) of various thiol reduction-mediated 99Tcm-IgG preparations. These are human IgG (Sandoglobulin) where the Fc-mediated complement activity is impaired, human IgG (Gammagard) where the Fc portion is left intact, and baboon IgG isolated from the serum of each animal (autologous): the first two preparations are commercially available. Normal baboon organ distributions were obtained for each tracer over a period of 3 h, commencing 4 h after administration. Similarly, lesion-to-background ratios in thigh and abdominal lesions (bacterial and chemical) were compared. Mean normal organ distributions (n = 6) were relatively constant during this period. Kidney uptake with IgG (Sandoglobulin) was significantly enhanced, as was liver uptake with IgG (Gammagard) and the baboon IgG. Biodistribution pattern changes after lesion induction tended to be similar for IgG (Gammagard) and baboon IgG, where activity washout became more prominent. Lesion-to-background ratios in the thigh far exceeded those in the abdomen, except for the individual animal's own IgG which performed well in this case.

Tissue Factor Localization in Non-Human Primate Cerebral Tissue

Tissue factor (TF), the principal procoagulant of human brain, resides in specific regions of the non-human primate central nervous system. Immunohistochemical studies employing murine anti-human TF monoclonal antibodies (MoAbs) detected TF antigen in the cortex, basal ganglia, cerebellum, and cervical spinal cord in three normal baboon subjects. Although significantly less prominent than human cortical gray matter, a distinct partition of TF in gray matter > white matter was noted. The gray matter predilection of TF was confirmed in primate temporal and parietal lobe cortex by both sandwich ELISA and one-stage coagulation assay. Variation in the relative quantity of TF antigen was observed by ELISA among the three subjects studied. Procoagulant activity followed the pattern of TF antigen (cortical gray matter > basal ganglia > or = cerebellum > cortical white matter), and was 96.5-98.5% inhibitable by a function inhibiting anti-human TF MoAb combination. TF antigen was associated with the microvasculature of all cerebral tissues studied, and spared capillaries most selectively in the cerebral cortex, basal ganglia, and cerebellum. These findings suggest a highly specific ordering of TF antigen and related procoagulant activity in the central nervous system of the baboon, confined primarily to gray matter parenchyma, and to the non-capillary microvasculature.

Maternal Blood Pressure and Fetal Ultrasonography in Normal Baboon Pregnancies

Pregnancy in baboons is characterized by lower systolic, diastolic, and mean blood pressures than in the nonpregnant state. As pregnancy progresses, diastolic and mean pressures tend to increase whereas systolic pressure remains low. Sonographic measurements of fetal growth follow a sigmoid pattern, but their increase in relation to length of gestation approximates a straight line between 6 and 21 weeks of gestation (23 to 84% of term).

Measurement of Cerebral Blood Flow and Volume with Positron Emission Tomography during Isoflurane Administration in the Hypocapnic Baboon

Using positron emission tomography, cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured after the addition of isoflurane (1.3 vols %, end-tidal concentration) to neuroleptanesthesia (fentanyl/droperidol) in hypocapnic baboons. The study was designed to determine whether isoflurane, when administered during hypocapnia, acted as a cerebral vasodilator to increase either CBF or CBV. Mean arterial pressure was maintained within 10% of preisoflurane levels with an angiotensin infusion. In the first protocol (A), CBF and CBV were measured as close together in time as possible in order to detect divergent effects of isoflurane on these variables. When PaCO2 was reduced from 40 mmHg to 25 mmHg, CBF decreased from 44 +/- 4 to 31 +/- 4 ml.100 g-1.min-1 (P less than 0.05) and CBV decreased from 3.1 +/- 0.3 to 2.6 +/- 0.3 ml/100 g (P less than .05). Neither CBF nor CBV was significantly changed by the addition of isoflurane. In the second protocol (B), serial CBV scans were performed frequently during the addition of isoflurane in a fashion designed to detect transient changes in CBV at the time isoflurane was first added to the breathing circuit. Induction of hypocapnia again reduced CBV from 3.1 +/- .3 to 2.7 +/- .2 ml/100 g, (P less than .05) and addition of isoflurane did not change CBV. From these results the authors conclude that in the normal hypocapnic baboon the addition of 1.3% isoflurane does not significantly change cerebral blood flow or volume.

Baboon Damage in Plantation Forestry in South Africa

SYNOPSIS Baboons damage all commercially important pine species by stripping bark, which results in deformation or death of trees and reduction in wood quality. Cones are also removed. Scale of damage appears to have increased recently in several plantation areas in both summer and winter rainfall regions and losses are estimated to total several million rand. Trees are generally susceptible between about age four to twenty years but exceptions occur at both ends of the scale. Selection for vigour and by position near compartment edges occurs. Stripping in plantations is an extension of normal baboon feeding behaviour, possibly enhanced by the superabundance of trees, but appears to be nutritionally unimportant. Geographically discontinuous incidence of damage is at least partly related to development of local stripping traditions. Baboon population densities are relatively high in two State forests suffering damage, possibly as a result of loss of habitat in adjacent agriculturally developed areas. Popul...