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PubMed2006

Using retrospective health data from the Gombe chimpanzee study to inform future monitoring efforts.

Disease outbreaks, either in isolation or in concert with other risk factors, can pose serious threats to the long-term persistence of mammal populations, and these risks become elevated as population size decreases and/or population isolation increases. Many chimpanzee study sites are increasingly isolated by loss of habitat due to human encroachment, and managers of parks that contain chimpanzees perceive that disease outbreaks have been and continue to be significant causes of mortality for chimpanzees. Major epidemics at Gombe National Park include suspected polio in 1966; respiratory diseases in 1968, 1987, 1996, 2000, and 2002; and sarcoptic mange in 1997. These outbreaks have led park managers and researchers working in Gombe to conclude that disease poses a substantial risk to the long-term survival of Gombe's chimpanzee population. We surveyed behavioral data records spanning 44 years for health-related data and found a combination of standardized and nonstandardized data for the entire period. Here we present the types of data found during the survey, discuss the usefulness of these data in the context of risk assessment, and describe how our current monitoring effort at Gombe was designed based on our findings.

Animals↗
PubMed1975

Comparative anatomy of the larynx in man and the chimpanzee: implications for language in Neanderthal.

Using the larynges of the newborn human and chimpanzee as models, Lieberman and Crelin ('71) and Lieberman, Crelin and Klatt ('72) have reconstructed the larynx of the "classic" Neanderthal La Chapelle aux Saints. The authors used their reconstructed vocal tract to generate linguistic functions which led them to conclude that Neanderthal lacked the ability to produce fully articulate human speech. In this paper, it is shown that their reconstruction of the larynx of Neanderthal is based on a placement of the hyoid bone of La Chapelle which is too high. The reconstructed hyoid bone of La Chalpelle which is too high. The reconstructed hyoid bone has been placed in a position unlike that occupied by hyoid bones of newborn humans, adult humans, stillborn chimpanzees or adult chimpanzees. In any laryngeal reconstruction, the function of swallowing must be taken into account. The ability of the reconstructed Neanderthal to swallow is discussed in light of a comparative analysis of swallowing in man and the chimpanzee. It is concluded that the statement that Neanderthal was less than fully articulate remains unsubstantiated because it rests on a questionable reconstruction of the larynx.

Animals↗
PubMed1987

Body weights of wild chimpanzees (Pan troglodytes schweinfurthii) of the Mahale Mountains National Park, Tanzania.

Ten male and nine female habituated chimpanzees (Pan troglodytes schweinfurthii) in the Kasoje area of the Mahale Mountains National Park, Tanzania, were weighed intermittently between December 1973 and March 1980 by luring them up a rope hung on a spring balance: six adult males averaged 42.0 kg and eight adult females 35.2 kg. Seasonal change in body weight was recognized at least partially; body weights tended to decrease in the later part of the wet season presumably because of food shortage in the middle of the wet season. Comparison of body weight among three populations of the same subspecies suggests that adult female chimpanzees of Mahale appear to be heavier than those of the Gombe National Park, Tanzania, and that they seem to be similar to the forest-living counterparts of eastern Zaire. On the other hand, body weights of adult male chimpanzees from the three populations do not show significant differences. Perhaps feeding competition among adult females in a small, isolated habitat is more severe than that among adult males, which may result in the body weight reduction among adult female chimpanzees at Gombe.

Animals↗
PubMed1988

Back muscle function during bipedal walking in chimpanzee and gibbon: implications for the evolution of human locomotion.

The evolution of erect posture and locomotion continues to be a major focus of interest among paleoanthropologists and functional morphologists. To date, virtually all of our knowledge about the functional role of the back muscles in the evolution of bipedalism is based on human experimental data. In order to broaden our evolutionary perspective on the vertebral region, we have undertaken an electromyographic (EMG) analysis of three deep back muscles (multifidus, longissimus thoracis, iliocostalis lumborum) in the chimpanzee (Pan troglodytes) and gibbon (Hylobates lar) during bipedal walking. The recruitment patterns of these three muscles seen in the chimpanzee closely parallel those observed in the gibbon. The activity patterns of multifidus and longissimus are more similar to each other than either is to iliocostalis. Iliocostalis recruitment is clearly related to contact by the contralateral limb during bipedal walking in both species. It is suggested that in both the chimpanzee and gibbon, multifidus controls trunk movement primarily in the sagittal plane, iliocostalis responds to and adjusts movement in the frontal plane, while longissimus contributes to both of these functions. In many respects, the activity patterns shared by the chimpanzee and gibbon are quite consistent with recent human experimental data. This suggests a basic similarity in the mechanical constraints placed on the back during bipedalism among these three hominoids. Thus, the acquisition of habitual bipedalism in humans probably involved not so much a major change in back muscle action or function, but rather an improvement in the mechanical advantages and architecture of these muscles.

Animals↗
PubMed1991

Mechanical implications of chimpanzee positional behavior.

Mechanical hypotheses concerning the function of chimpanzee anatomical specializations are examined in light of recent positional behavior data. Arm-hanging was the only common chimpanzee positional behavior that required full abduction of the humerus, and vertical climbing was the only distinctive chimpanzee positional behavior that required forceful retraction of the humerus and flexion of the elbow. Some elements of the chimpanzee anatomy, including an abductible humerus, a broad thorax, a cone-shaped torso, and a long, narrow scapula, are hypothesized to be a coadapted functional complex that reduces muscle action and structural fatigue during arm-hanging. Large muscles that retract the humerus (latissimus dorsi and probably sternocostal pectoralis major and posterior deltoid) and flex the elbow (biceps brachii, probably brachialis and brachioradialis) are argued to be adaptations to vertical climbing alone. A large ulnar excursion of the manus and long, curved metacarpals and phalanges are interpreted as adaptations to gripping vertical weight-bearing structures during vertical climbing and arm-hanging. A short torso, an iliac origin of the latissimus dorsi, and large muscles for arm-raising (caudal serratus, teres minor, cranial trapezius, and probably anterior deltoid and clavicular pectoralis major) are interpreted as adaptations to both climbing and unimanual suspension.

Adaptation, Physiological↗
PubMed1993

Sex differences in adult chimpanzee positional behavior: the influence of body size on locomotion and posture.

Focal animal instantaneous sampling of adult male and female chimpanzee positional behavior was conducted during a 7-month study in the Tai Forest, Ivory Coast, in order to determine whether there are sex differences in the locomotion, posture, substrate use, and height preference of sexually dimorphic adult chimpanzees, and if so, whether these differences support predictions based on body size differences. Results indicate that as predicted, adult male and female chimpanzees differ in their arboreal locomotor behavior, with the larger males using less quadrupedalism and more climbing, scrambling, and aided bipedalism than females during feeding locomotion. There is a sex difference in height preference as well, with female chimpanzees consistently using more arboreal behavior than males, primarily during resting. Although it has been previously demonstrated that separate primate species of differing body size differ in locomotor and postural activities (Fleagle and Mittermeier, 1980; Crompton, 1984), this study clearly demonstrates that body size differences within a species can also be correlated with differences in locomotor behavior. These findings may influence how we interpret sex differences in body size of extinct species.

Animals↗
PubMed2003

Morphology and histology of chimpanzee primary visual striate cortex indicate that brain reorganization predated brain expansion in early hominid evolution.

Human brain evolution is characterized by an overall increase in brain size, cerebral reorganization, and cerebral lateralization. It is generally understood when brain enlargement occurred during human evolution. However, issues concerning cerebral reorganization and hemispheric lateralization are more difficult to determine from brain endocasts, and they are topics of considerable debate. One region of the cerebral cortex that may represent the earliest evidence for brain reorganization is the primary visual cortex (PVC), or area 17 of Brodmann. In nonhuman primates, this region is larger in volume (demarcated anteriorly by the lunate sulcus), and extends further rostrally than it does in modern humans. In early hominid fossil (Australopithecus) endocasts, this region appears to occupy a smaller area compared to that in nonhuman primates. Some have argued that the brain first underwent size expansion prior to reorganization, while others maintain that reorganization predated brain expansion. To help resolve this question, we provide a description of two male, common chimpanzee (Pan troglodytes) brains, YN77-111 and YN92-115, which clearly display a more posterior lunate sulcal morphology than seen in other chimpanzees. These data show that neurogenetic variability exists in chimpanzees, and that significant differences in organization (e.g., a reduced PVC) can predate brain enlargement. While the human brain has experienced numerous expansion and reorganization events throughout evolution, the data from these two chimpanzees offer significant support for the hypothesis that the neurogenetic basis for brain reorganization was present in our early fossil ancestors (i.e., the australopithecines) prior to brain enlargement.

Animals↗
PubMed2005

Surface bone histology of the occipital bone in humans and chimpanzees.

Human and chimpanzee occipital bones are thought to grow and develop in distinctly opposite bone remodeling patterns. Preliminary research examining growth-remodeling fields (GRFs) from the surfaces of the occipital bone in modern humans and chimpanzee indicates this may not be entirely correct. By using vinyl/resin-casting techniques, coupled with scanning electron and reflected-light microscopy, GRF profiles from a cross-sectional sample of humans and chimpanzees have documented the ongoing histological activities that reflect developmental processes through which taxon-specific ontogenetic trajectories alter bone morphology. Surface bone profiles aid in explaining how the posterior skull takes shape, thereby aiding in our understanding of the developmental processes that may contribute to the morphological variation in the posterior skull in humans and chimpanzees.

Animals↗
PubMed2006

Duplication and divergence in humans and chimpanzees.

It has become a truism that we humans are genetically about 99% identical to chimpanzees. The origins of this assertion are clear: among early studies of DNA sequences, nucleotide identity between humans and chimpanzees was found to average around 98.9%.(1) However, this figure is correct only with respect to regions of the genome that are shared between humans and chimpanzees. Often ignored are the many parts of their genomes that are not shared. Genomic rearrangements, including insertions, deletions, translocations and duplications, have long been recognized as potentially important sources of novel genomic material(2,3) and are known to account for major genomic differences between humans and chimpanzees.(4) Further, such changes have been implicated in a number of genetic disorders, such as DiGeorge, Angelman/Prader-Willi and Charcot-Marie-Tooth syndromes.(5)

Animals↗
PubMed1983

"Conservations" with a chimpanzee.

Two chimpanzees (Pan tryglodytes), Fanny and Jane, were presented with liquid and number conservation problems. One chimpanzee, Jane, was successful in solving both sets of problems in that she was not distracted by irrelevant transformations, being influenced only by changes in quantity. Her success appeared to be based on the ability to make inferences rather than on simple perceptual judgement of the final comparison. The results are compared and contrasted with those of Premack, in G. Woodruff, D. Premack, and K. Kennel [(1978). Conservation of liquid and solid quantity by the chimpanzee. Science, 202:99-994] and J. Mehler and T. G. Bever [(1967). Cognitive capacity of very young children. Science, 158:141-142; (1968). Quantification, conservation and nativism. Science, 162:979-981], and it is suggested that there may be a similarity of conservation development between chimpanzees and man.

Animals↗
PubMed1990

Organization of the chimpanzee C4-CYP21 region: implications for the evolution of human genes.

We prepared a cosmid library from chimpanzee DNA and screened it with a mouse probe specific for the complement component 4 (C4)-encoding gene. We isolated 29 clones and constructed restriction maps for 20 of these. The clones could be arranged into two overlapping clusters covering the entire C4 region of both chromosomes in this particular heterozygous chimpanzee. The region is about 100 kilobases (kb) long and contains two C4 and two CYP21 genes, the latter coding for the enzyme 21-hydroxylase. Using oligonucleotide probes we identified the genes as corresponding to human C4A, C4B, CYP21 and CYP21P genes. The last gene apparently contains an 8-base pair (bp) deletion (as does the corresponding human gene), which renders it a pseudogene. The genes are arranged in the order C4A...CYP21P...C4B...CYP21. Each of the two C4 genes is 16 kb long and thus corresponds to the short version of the human C4 genes. We suggest that the duplication of the basic C4-CYP21 unit that generated the standard arrangement of the human C4-CYP21 region occurred before the separation of the evolutionary lineages leading to humans and chimpanzees (i.e., more than five million years ago). We suggest further that the original form of the C4 gene was of the long variety and was generated by the insertion of a 6.8-kb element into one of the C4 introns. The element was subsequently excised in the ancestors of the chimpanzees and in at least one lineage of the human C4B gene. We speculate that the presence of the 6.8-kb insert in the human C4A and some C4B genes might largely be responsible for the great instability of this chromosomal region which leads to frequent duplications and deletions, some of which cause 21-hydroxylase deficiency.

Animals↗
PubMedDate not supplied

Serial passage of hepatitis delta virus in chronic hepatitis B virus carrier chimpanzees.

Five consecutive passages of hepatitis delta virus in hepatitis B virus carrier chimpanzees were performed in order to further characterize the infectious and pathogenic nature of this naturally occurring defective virus. Three animals received identical inocula at fourth passage in order to assess individual animal variation as a factor in the course of infection and disease. Acute hepatitis delta virus infection occurred in all hepatitis B virus carrier chimpanzees as demonstrated by coincident intrahepatic hepatitis delta antigen, serum hepatitis delta antigen and serum hepatitis delta virus RNA followed by seroconversion to antibody to hepatitis delta antigen. In all animals, acute hepatitis was temporally associated with hepatitis delta virus infection and was self-limited. The incubation period to hepatitis shortened with passage, whereas biochemical and histologic evidence of liver diseases increased. The marked increase in liver disease with passage was not associated with increasing markers of hepatitis delta virus replication or expression, thus indicating that adaptation to the chimpanzee by serial passage resulted in increased hepatitis delta virus virulence. The duration of hepatitis due to hepatitis delta virus infection in three chimpanzees which received the same inoculum varied from 1 to 8 months. The observations of passage adaptation and individual host variation in this experimental model of hepatitis delta virus disease parallel known pathogenic variations in human hepatitis delta virus infection.

Animals↗
PubMed2006

Genomic response to interferon-alpha in chimpanzees: implications of rapid downregulation for hepatitis C kinetics.

The mechanism of the interferon-alpha (IFN-alpha)-induced antiviral response during hepatitis C virus (HCV) therapy is n o t completely understood. In this study,we examined the transcriptional response to IFN-alpha in uninfected chimpanzees after single doses of chimpanzee, human, or human-pegylated IFN-alpha. Liver and peripheral blood mononuclear cell (PBMC) samples were used for total genome microarray analysis. Most induced genes achieved maximal response within 4 hours, began to decline by 8 hours, and were at baseline levels by 24 hours postinoculation, a time when high levels of circulating pegylated IFN-alpha were still present. The rapid downregulation of the IFN-alpha response may be involved in the transition between the observed phase I and phase II viral kinetics during IFN-alpha therapy in HCV-infected patients. The response to all three forms of IFN-alpha was similar; thus, the reasons for previous failures in antiviral treatment of chimpanzees with human IFN-alpha were not due to species specificity of IFN-alpha. The response to IFN-alpha was partially tissue-specific. A total of 1778 genes were altered in expression by twofold or more by IFN-alpha, with 538 and 950 being unique to the liver or PBMC, respectively. Analysis of the IFN-alpha and IFN-gamma responses in primary chimpanzee and human hepatocytes were compared as well. IFN-alpha and IFN-gamma induced partially overlapping sets of genes in hepatocytes. In conclusion, the response to IFN-alpha is largely tissue-specific, and the response is rapidly downregulated in vivo, which may have a significant influence on the kinetics of antiviral response.

Animals↗
PubMed1988

Nucleotide sequences of chimpanzee MHC class I alleles: evidence for trans-species mode of evolution.

To obtain an insight into the evolutionary origin of the major histocompatibility complex (MHC) class I polymorphism, a cDNA library was prepared from a heterozygous chimpanzee cell line expressing MHC class I molecules crossreacting with allele-specific HLA-A11 antibodies. The library was screened with human class I locus-specific DNA probes, and clones encoding both alleles at the A and B loci have been identified and sequenced. In addition, the sequences of two HLA-A11 subtypes differing by a single nucleotide substitution have been obtained. The comparison of chimpanzee and human sequences revealed a close similarity (up to 98.5%). The chimpanzee A locus alleles showed greatest similarity to the human HLA-A11/A3 family of alleles, one of them being very close to HLA-A11. Similarly, segments of the ChLA-B alleles displayed greatest similarity to certain HLA-B alleles. The calculated evolutionary branch point for the A11-like alleles is 7 x 10(6) to 9 x 10(6) years, whereas the other A locus alleles diverged between 12 x 10(6) and 17 x 10(6) years ago. Since the human and chimpanzee lineages separated 5 x 10(6) to 7 x 10(6) years ago, our data support the notion that during evolution, MHC alleles are transmitted from one species to the next.

Alleles↗
PubMed1979

Experimental infection of chimpanzees with antihemophilic (factor VIII) materials: recovery of virus-like particles associated with non-A, non-B hepatitis.

Non-A, non-B viral hepatitis was transmitted to four colony-born chimpanzees by infusion of three lots of antihemophilic factor (factor VIII) implicated in the transmission of non-A, non-B hepatitis to two human recipients. All four inoculated animals showed histopathological evidence of viral hepatitis, and all demonstrated significant ALT elevations between seven and one-half weeks after inoculation. Acute-phase plasma from one of the infected chimpanzees (no. 771) was shown to induce non-A, non-B hepatitis in two other chimpanzees approximately three weeks after their inoculation. In addition, an acute-phase open liver wedge biopsy obtained from animal no. 771 was processed and examined by immune electron microscopy (IEM) for virus-like particles with convalescent serum from a serologically confirmed case of non-A, non-B hepatitis. Twenty-five to 30 nm (mean = 27 nm) diameter virus-like particles that were either "full" or "empty" were identified in this liver preparation by IEM. Two additional chimpanzees inoculated with a cesium chloride gradient fraction of an isopycnically banded liver homogenate (animal no. 771) also developed elevated ALT activity two to two and one-half weeks later. Our findings have experimentally verified that commercially produced factor VIII materials can induce non-A, non-B hepatitis in champanzees and that the disease can be subpassaged in these animals by inoculation of either acute-phase plasma or liver. These results also provide evidence for the association of 27 nm-diameter virus-like particles with non-A, non-B viral hepatitis.

Adult↗
PubMed1980

Hepatitis B e antigen and antibody: detection by radioimmunoassay in chimpanzees during experimental hepatitis B.

Hepatitis B e antigen (HBeAg) and its antibody (anti-HBe) were evaluated using a sensitive radioimmunoassay (RIA) in weekly serum samples obtained from nine chimpanzees experimentally infected with hepatitis B virus (HBV). In two chimpanzees with HBV infection with detectable hepatitis B surface antigen (HBsAG) for less than five weeks, and in one chimpanzee with documented HBV infection with no detectable HBsAg, HBeAg was not detected; in all three, anti-HBe became detectable early in the infection. In six chimpanzees in which HGsAg was detected for 16 weeks or longer, HBeAg was detected early in the infection; in five, anti-HBe became detectable and HBeAg undetectable prior to the clearance of HBsAg. The sixth remained HGsAg-positive and HBeAg-positive for more than two years and never developed anti-HBe. These results confirmed the sensitivity of this RIA and its value in predicting the course of HBV infections.

Animals↗
PubMed1987

Splenic replication of hepatitis B virus in the chimpanzee chronic carrier.

Low levels of hepatitis B virus (HBV) replication and serum Dane particles have been commonly observed in chimpanzee chronic HBV carriers. To evaluate the possibility of extrahepatic sites of replication, DNA from various organs of a chimpanzee HBV carrier were evaluated by Southern blot analysis. With cloned, repurified HBV DNA of 3.2 kilobases (Kb) as a hybridization probe under stringent conditions, analysis of liver DNA revealed a diffuse hybridization pattern below 3.2 Kb and full-length double-stranded HBV genomes at 3.2 and 1.8 Kb, the latter representing the supercoiled (CCC) form found in the nucleus. No HBV DNA was found in pancreas, muscle, renal, or adrenal gland. Analysis of splenic DNA revealed diffuse hybridization below 3.2 Kb within the cytoplasmic subcellular fraction, and full-length HBV genomic forms in the nuclear fraction of splenic tissue. Use of (-) and (+) strand-specific HBV DNA and RNA probes demonstrated asymmetric viral replication within the spleen cytoplasm as previously demonstrated in liver. Northern blot analysis of total RNA from chimpanzee spleen and liver revealed HBV RNA sequences in both of these tissues, suggesting active viral gene expression and/or replication in chimpanzee spleen as well as in liver. Elucidation of the splenic cell type supporting viral propagation may serve as a basis for development of a tissue culture system to study molecular events of HBV replication.

Animals↗
PubMed1987

Inactivation of 10(15) chimpanzee-infectious doses of hepatitis B virus during preparation of a heat-inactivated hepatitis B vaccine.

The safety of a plasma-derived hepatitis-B vaccine inactivated by two heating steps (90 sec at 103 degrees C followed by 10 hr pasteurization at 65 degrees C) was validated in chimpanzees; 10(3) chimpanzee-infectious doses (CID50) of hepatitis-B virus (HBV), subjected to the purification steps during production of the vaccine, were noninfectious in two chimpanzees. Furthermore, 10(6) CID50 of HBV heated at 103 degrees C for 90 sec and another 10(6) CID50 of HBV heated at 65 degrees C for 10 hr, were also not infectious in two other chimpanzees. All animals developed hepatitis-B infection after subsequent challenge with the untreated starting material, before the respective purification and inactivation procedures. Thus, the total reduction of infectivity of HBV during production of this vaccine was established to be at least 10(15) CID50.

Animals↗