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At least 37 records · Page 2Linked to original sources
PubMed1981

Notes on African Haemaphysalis ticks, XIII. identity of H. (Rhipistoma) cooleyi, a parasite of the rock hyrax in South Africa (Acarina: Ixodidae).

The lectotype male, allotype female, and paratype nymph of Haemaphysalis (Rhipistoma) cooleyi Bedford, 1929, a parasite of the rock hyrax, Procavia capensis, in the Transvaal, are redescribed and illustrated to provide reliable criteria for differentiating between haemaphysaline parasites of hyraxes. Keys are included for identifying adults of these Haemaphysalis ssp. (orientalis Nuttall & Warburton, 1915; bequaerti Hoogstraal, 1956; cooleyi Bedford, 1929; hyracophila Hoogstraal, Walker & Neitz, 1971).

Animals↗
PubMed1997

Natural Leishmania infection in rock hyrax, Procavia capensis (Pallas, 1766) order: Hyracoidea, trapped in Najran, Saudi Arabia.

Cutaneous leishmaniasis caused by Leishmania major (zoonotic, ZCL) and L. tropica (anthroponotic, ACL) is found in most countries of the Eastern Mediterranean Region. Phlebotomus papatasii is the proven vector of L. major and rodents Rhombomys opimus, Psammomys obesus, Meriones spp. and Gerbillus spp. serve as animal reservoirs. Ph. sergenti is the vector of L. tropica in the majority of endemic foci. On the other hand; in the Eastern African highlands (mainly Ethiopia and Kenya), stable foci of L. aethiopica are maintanined by hyraxes and transmitted by Ph. longipes and Ph. pedifer. In this paper, natural Leishmania sp. infection was demonstrated serologically (IHAT) and parasitologically (smear examination) in two out of four rock hyraxes trapped in the highlands of Najran, southern part of the Kingdom. It is concluded that the identity of the Leishmania parasite(s)in such a focus is essential since it has implication in control and treatment. Also, passive case-detection and isolates from man and sandfly in the vicinity of Najran for typing is a must.

Animals↗
PubMed1997

Characterization of Leishmania aethiopica from rock hyrax, Procavia capensis trapped in Najran, Saudi Arabia.

Cutaneous leishmaniasis caused by L. aethiopica is endemic in Ethiopia, Kenya and South-west Africa. In a previous paper, the present authors reported natural Leishmania species infection in two hyraxes, P. capensis. In this paper, an isolate from a rock hyrax. P. capensis (Pallas, 1766) was enzymatically characterized by demonstrating the mobilities of seven enzymes, to be identical with the reference strain of L. aethiopica.

Animals↗
PubMed2004

Rapid maxillary expansion with palatal anchorage of the hyrax expansion screw--pilot study with case presentation.

BACKGROUND: Rapid maxillary expansion (RME) with the appliance fixed at the crowns of the first premolars and molars leads not only to transversal expansion but also to tipping of the anchorage teeth and a risk of increased tooth mobility as well as of root and bone resorptions. These disadvantages were to be avoided by fixing the transversal screw directly to the hard palate. MATERIAL AND METHOD: Following preliminary experimental work to determine the extent to which the hard palate could be loaded with orthodontic implants, two female patients were treated for extreme transverse maxillary deficiency using a Hyrax expansion screw fixed on one side with an implant with the following dimensions: length 4.0 mm, diameter 3.5 mm, abutment diameter 5.00 mm (EO implant, Straumann, Freiburg i. Br., Germany), and on the other side with a bone screw between the roots of the second premolars and the first molars. Presurgical osteotomy according to Glassmann was followed immediately by loading, i. e. by expansion through activation of the screw several times per day. Additional anterior guidance of the right and left maxilla was provided by crossed segmented archwires and a tension coil spring for space opening in the incisor region. After adequate expansion by 8.0 mm and correction of the position of the buccal teeth, the Hyrax expansion screw and the osteosynthesis screw were removed. The implant served as orthodontic anchorage for a molar-to-molar transpalatal bar aimed at preventing relapse. RESULTS AND CONCLUSIONS: The tooth axis inclination measured on cut sections of the plaster casts made at the beginning and end of treatment was largely without transversal discrepancies. Direct fixing of the transversal screw in the palatal arch prevents buccal tipping of the posterior teeth, especially in patients with a small apical base. Compared with other direct procedures involving osteosynthesis plates, this technique offers adequate guiding stability and is minimally invasive.

Adult↗
PubMed1997

Comparison of Hyrax and bonded expansion appliances.

The majority of rapid maxillary expansion studies have reported the use of appliances with metal bands attached to the posterior teeth. Tooth extrusion, dental tipping, and an increase in the vertical dimension are often encountered, which may not coincide with treatment objectives. Bonded appliances using interocclusal acrylic may control the vertical dimension and expand the maxillary halves in a more bodily and symmetrical fashion. The purpose of this clinical trial was to determine, by radiographic analysis, the differences between a conventional banded expander (Hyrax) and a bonded acrylic expander. Fourteen patients who exhibited a need for expansion were enrolled in the study. The results suggest that the increase in the vertical dimension often seen with the more conventional Hyrax appliance may be minimized or negated with the bonded appliance. However, there appeared to be no significant difference between the amount of dental tipping or symmetrical expansion between the two appliances, as previously theorized.

Acrylic Resins↗
PubMed1992

Electron microscopic structure and innervation of the carotid baroreceptor region in the rock hyrax (Procavia capensis).

Semi-thin plastic sections reveal that the carotid baroreceptor region in the rock hyrax comprising the origin of the internal carotid artery has a preponderantly elastic structure and a thick tunica adventitia. In contrast, the common carotid artery has a musculoelastic structure, whereas the cranial segment of the internal carotid artery (immediately distal to the baroreceptor areas) shows the features of a muscular artery. Electron microscopy discloses the presence of sensory nerve endings within the parts of the tunica adventitia adjoining the preponderantly elastic zone of the internal carotid artery. These nerve endings are characterized by varicose regions containing a large quantity of mitochondria. Bundles of collagen fibers in the tunica adventitia form convolutions or whorls around the nerve terminals and often terminate on the surface of the elastic fibers or into the basement membranes of the neuronal profiles. The large content of elastic tissue in the tunica media of the baroreceptor region may render the vessel wall highly distensible to intraluminal pressure changes. This, in turn, would facilitate the transmission of the stimulus intensity to the sensory nerve terminals located in the tunica adventitia. It is suggested that the stretching of elastic fibers may form the main mechanical event leading to the distortion of the associated nerve terminals. However, a change in the geometrical configuration of the bundles of collagen under the influence of the elastic fibers may provide a better insight into the mechanisms of distortion of the baroreceptors related to and/or in contact with collagen fibers.

Animals↗
PubMed1991

In vitro metabolism of progesterone by peripheral blood of rock hyrax (Procavia capensis).

In vitro metabolism of progesterone by hyrax whole blood, erythrocytes, or plasma in the presence or absence of NADPH was investigated. In the presence of NADPH, whole blood metabolized progesterone to 5 alpha-pregnanedione and 5 beta-pregnanedione, but in the absence of NADPH, only 5 beta-pregnanedione was produced. Erythrocytes in the presence and the absence of NADPH produced only 5 beta-pregnanedione. The plasma component of blood metabolized progesterone to give 5 alpha-pregnanedione, but only in the presence of NADPH. These results suggest the presence of two types of steroid reductases found in plasma and erythrocytes. The extent of progesterone metabolism by the blood of animals in different reproductive states is in the order of pregnant females greater than nonpregnant females greater than male.

Animals↗
PubMed1984

Metabolic rate and body temperature of adult and juvenile hyrax (Procavia capensis).

Resting metabolic rates (RMR) below thermoneutrality in adult hyrax acclimated to 26, 15 and 10 degrees C remained unchanged, i.e. thermal conductance (K) remained constant. Conductance in juveniles decreased with acclimation to lower ambient temperatures (Ta). Body temperature (Tb) dropped by 3.8 degrees C in adults exposed to Ta of 30-5 degrees C. The decrease was constant. Body temperature fell by 1.5 degrees C in juveniles exposed to Ta of 30-20 degrees C but stabilized between 20 and 5 degrees C. The labile Tb, associated with behavioural strategies and lower than predicted RMR, can be seen as an energy-conserving mechanism of particular importance during winter conditions.

Acclimatization↗
PubMed1994

The gastrointestinal tract of the rock hyrax (Procavia habessinica). 1. Morphology and motility patterns of the tract.

The stomach of the rock hyrax (Procavia habessinica) is divided into a non glandular part with very slow movements, and a glandular part which rapidly mix the digesta. The large intestine has two fermentation chambers, the caecum, which rapidly mixes the digesta, and the colonic sac, which efficiently, but slowly, mixes digesta. Between these chambers runs the connecting colon. No retrograde transport is observed in any part of the large intestine.

Animals↗
PubMed1977

Sites of organic acid production and patterns of digesta movement in the gastrointestinal tract of the rock hyrax.

The rock hyrax, smallest of the present day ungulates and a near relative of the elephant, has a gastrointestinal tract of such complex nature that it may be considered ccomparable to both the simple and complex stomach mammals, and also to birds. They have a stomach to body weight capacity equal to that of sheep. But for all its complexity, the passage of ingesta is reasonably rapid. However, there are three major sites of digesta retention and microbial fermentation of the ingested material. The cranial stomach provides the first major site of fermentation with VFA levels comparable to those observed in the rumen (125-145 mM/liter). Quantities of lactic acid are also produced in the foregut where the pH may vary from 2 to 5.5. The ingested particulate material is exclusively retained in the cranial half of the stomach for 4 hours after consumption, and partially retained in the entire stomach for greater than 24 hours. The mid-gut sacculation provides the second major site of fermentation with the retention of the digesta in this gut segment for up to 16 hours. The two ceca provide the third site. Concentrations of VFA in these latter two gut segments approaches 80 mM/liter, while the near stable and neutral pH corresponds to the absence of lactic acid production.

Animals↗
PubMed1992

Geographic mitochondrial DNA variation in the rock hyrax, Procavia capensis.

Restriction-fragment-length polymorphisms in mitochondrial DNA (mtDNA) were used to evaluate geographic population genetic structure in the rock hyrax, Procavia capensis, a species which occurs widely, though restricted to rocky habitat, throughout South Africa. Ten restriction endonucleases were employed to assay mtDNAs from 55 specimens representing 10 localities. Haplotypes showed strong geographic patterning, and estimates of nucleotide sequence divergence indicate two major clades thought to be dispersing along separate routes. The divergence time of approximately 2 Myr between clades is relatively high for intraspecific variation. We speculate that the marked genetic break distinguishing the northwestern populations from those constituting the south/central clade may be indicative of two species in what has conventionally been regarded as P. capensis.

Animals↗
PubMed1983

Electron microscopic study of the chorioallantoic placenta of the rock hyrax (Heterohyrax brucei).

The interhaemal membrane consisted of only two cellular elements: a single layer of cellular trophoblast and the fetal capillary endothelium. The hyrax is therefore one of the few mammals known to possess the cellular haemomonochorial type of placenta. The trophospongium was also cellular while the basal trophoblastic cells were strongly phagocytic. The giant multinucleate cells at the feto-maternal junction were ultrastructurally different from the trophoblast cells and showed no signs of degeneration. Their appearance suggests that they are of maternal rather than fetal origin.

Animals↗
PubMed2006

Isolation of a Mycobacterium microti-like organism from a rock hyrax (Procavia capensis) in a Canadian zoo.

A Mycobacterium tuberculosis complex organism was isolated from a zoo resident rock hyrax (Procavia capensis) imported into Canada from South Africa. The strain was identified biochemically as Mycobacterium microti. The spoligotype pattern obtained for this isolate was found to be rare. This represents the first report of isolation and spoligotyping of M. microti in North America.

Animals↗
PubMed1995

The gastrointestinal tract of the rock hyrax (Procavia habessinica). 2. Fluid flow, production of short chain fatty acids and absorption of water and electrolytes.

In the digestive tract of the rock hyrax (Procavia habessinica), water is absorbed from the small intestine and from the wider part of the connecting colon running between the caecum and the colonic sac. Only little water absorption occurs from these two fermenting chambers. The outflow from the caecum is much higher than from the colonic sac mainly due to the effective absorption in the connecting colon with its very large absorptive area. A significant lower osmolality was found in the caecal contents compared with the contents in the colonic sac. The Na/K ratio was 10.7 and 1.7, respectively in these sections. Short chain fatty acids are produced at a rate of nearly 10 mmol/100 ml/hr in the contents of both the caecum and the colonic sac. The results are discussed in relation to the findings in domestic and laboratory animals.

Animals↗
PubMed1986

Paenungulata: a comparison of the hemoglobin sequences from elephant, hyrax, and manatee.

Inspection of the amino acid differences among hemoglobin sequences of a wide range of mammalian species suggested that at alpha 19, alpha 110, alpha 111, beta 23, beta 44, and beta 56, synapomorphies group manatee (Trichechus inungius, Sirenia), Indian and African elephant (Elephas maximus and Loxodonta africana, Proboscidea), and rock hyrax (Procavia habessinica, Hyracoidea) into a monophyletic clade. Results obtained by parsimony analysis provide evidence for this grouping--and thus support for the genealogical validity of Simpson's superorder Paenungulata, which contains as the extant orders Proboscidea, Sirenia, and Hyracoidea. All of the 39 most, or nearly most, parsimonious of 10,395 trees constructed from a tandemly combined alpha- and beta-hemoglobin sequence for 103 vertebrate species (of which 79 were mammals from 16 extant orders), depicted Paenungulata as one of the most anciently separated branches of Eutheria. It was found on examining thousands of alternative trees that to not group Proboscidea, Hyracoidea, and Sirenia in a monophyletic clade required at least four additional substitutions.

Amino Acid Sequence↗
PubMed2006

Cephalometric evaluation of molar distalization by hyrax screw used in conjunction with a lip bumper.

AIM: To determine the treatment effects of the Hyrax screw, when used with a lip bumper appliance, on the distalization of maxillary molars and the reciprocal effects on the anchor premolars and maxillary incisors. METHODS: Records, including study casts, lateral cephalometric radiographs, extra- and intraoral photographs of 9 patients were taken at the start of treatment and after distalization was achieved. Wilcoxon signed rank test was performed to analyze the skeletal and dental changes. RESULTS: During the active period of maxillary molar distalization, the maxillary incisors significantly proclined by 5.89 degrees (P <.05), 5.39 degrees (P <.05), and 1.72 mm (P <.05) relative to the SN, RH, and RV planes, respectively. The maxillary first molars showed significant distal crown tipping, as evidenced by 4.61-degree (P = .00), 4.17-mm (P = .00), and 1.11-mm (P = .02) decreases in U6-RH angle, U6 perpendicular RV, and U6 perpendicular RH distances respectively. Anchorage loss, with 4.17 mm mesial movement of the maxillary second premolars, was significant (P = .01). CONCLUSION: When selecting the appropriate method for maxillary molar distalization, anchorage loss potential, the need for patient compliance, and the duration of treatment should be considered.

Adolescent↗
PubMed1993

Cephalometric evaluation of Haas and Hyrax rapid maxillary appliances in the treatment of the skeletal maxillary transverse deficiency.

Two different rapid palatal expansion appliances were compared, using lateral cephalograms, anterio-posterior cephalograms and diagnostic models. The Haas appliance was used on ten patients and the Hyrax appliance on another ten. A difference in the effect of the two appliances was found only for the increase in intermolar distance. This difference could be the result of the different appliance design.

Adolescent↗