Showing papers by "University of Queensland published in 1968"

The actions of caerulein on the smooth muscle of the gastrointestinal tract and the gall bladder.

Abstract: 1. In the intact conscious dog, caerulein causes emesis and evacuation of the bowel. The mean effective dose by the intravenous route is 0.4-0.5 mug/kg, and by the subcutaneous route 3-4 mug/kg.2. The gall bladder in situ or as an isolated preparation is highly sensitive to caerulein. A few ng/kg injected intravenously are sufficient to stimulate the gall bladder in situ and less than 1 ng/kg per min is effective when infused intravenously. The isolated gall bladder is contracted by caerulein in concentrations as low as 0.03-2 ng/ml. Krebs solution. There is no tachyphylaxis but, generally, a good dose-response relationship. Hence the gall bladder, especially that of the guinea-pig, appears to be very suitable for the bioassay of caerulein and related peptides.3. In situ, the musculature of the gastrointestinal tract is also highly sensitive to caerulein. Doses as low as 1-5 ng/kg, administered intravenously, have a spasmogenic action on jejunal loops of the dog, and slightly larger doses contract the small intestine of the cat. The stomach and the large intestine seem to be somewhat less sensitive to the polypeptide. Caerulein has a considerable spasmogenic action on the rat pylorus but relaxes the sphincter of Oddi of the guinea-pig.4. Isolated preparations of the gastrointestinal tract are relatively insensitive to caerulein and tachyphylaxis occurs readily.5. Blockade with atropine produces different effects in different intestinal segments and in different animal species. The spasmogenic action of caerulein on the gall bladder is atropine-resistant.6. The effects of caerulein are similar to those of cholecystokinin-pancreozymin in the organs tested in situ or as isolated preparations. Caerulein, however, is always more potent than cholecystokinin-pancreozymin, even on a molar basis. Compared with caerulein, human gastrin I has negligible activity.7. The possible use of caerulein in cholecystography is discussed.

The feeding processes of the cattle tick Boophilus microplus (Canestrini): Part II. The sequence of host-tissue changes

Abstract: The development of the feeding lesions of the ixodid tick Boophilus microplus was followed throughout the parasitic life-cycle on cattle of both Zebu and European breeds, using histological techniques.The feeding lesion of this tick must be the result of an interaction between the tick and its host as it is neither the result of simple mechanical trauma, nor of lysis of the host tissues by salivary secretions of the tick alone, nor is it solely a result of an inflammatory response.The histological evidence suggests that the diet of the tick in each instar changes as the lesion develops; first, tissue fluids are available, then tissue fluids along with leucocytes which have infiltrated the lesion, and finally these two components along with whole blood.An early intense infiltration of eosinophils into the area of the mouthparts, typical of an immediate hypersensitive or anaphylactic response, was noted with European cattle on secondary and subsequent exposures to larvae. Hypersensitivity to tick infestation, which has been equated with resistance to infestation, was seen as an extreme of a normal spectrum of sensitization which results in an abnormal susceptibility.The definitive lesion was similar with all hosts studied. It consisted of a cavity containing leucocytes, predominantly neutrophils, some lymphocytes and erythrocytes in an area of heavily infiltrated collagen.It is concluded that this host-parasite relationship illustrates the concept of adaptation tolerance as proposed by Sprent (1962).It is with much pleasure that we acknowledge the continued generous financial support by the Australian Meat Research Committee (formerly the Australian Cattle and Beef Research Committee), which has made possible this project.

Trace and minor element geochemistry of the rhyolitic volcanic rocks, Central North Island, New Zealand

Abstract: Analytical data are presented for the following elements: Cs, Rb, Ba, K, Sr, Ca, Na, Fe, Mg, Cu, Co, Ni, Li, Sc, V, Cr, Ga, Al, Si, La, Y, and Zr. Eight samples were analysed by the spark source method for rare earths, Tl, Pb, Hf, Sn, Nb, Mo, Bi, and In. In addition to data on rhyolitic volcanics, a small number of intermediate volcanics and eugeosynclinal sediments were analysed for comparative purposes.

Notes on Ascaris and Toxascaris, with a definition of Baylisascaris gen.nov.

Abstract: The family Ascarididae, as defined by Hartwich (1957) and emended by Osche (1958), comprises species in the genera Ascaris, Toxascaris, Parascaris and Lagochilascaris, all occurring in terrestrial mammals Other ascaridoids of terrestrial mammals occur in Crossophoridae and Toxocaridae, the latter including Toxocara and Neoascaris (see Hartwich, 1957; Sprent, 1957; Osche, 1958)

The geochronology of the igneous rocks of Eastern Queensland

Abstract: Isotopic dating of igneous rocks in eastern Queensland south of Bowen has indicated phases of granite emplacement in the Devonian (360 m.y.), Carboniferous (310 and 285 m.y.), Permian (265, 245 and 235 m.y.), Triassic (220 m.y.) and Cretaceous (125 and 110 m.y.). This activity moved generally eastwards with time. The combination of Rb‐Sr and K‐Ar dating has produced a better understanding of the geological history in the complex area of the Connors Arch than would have resulted from the use of either method alone. Also, it was found that, contrary to predictions that the argon retentivity of hornblende is greater than that of biotite during metamorphism, the two minerals had a similar degree of retentivity under burial metamorphism. The relationship between granite intrusion and tectonic phases is examined. The emplacement of Carboniferous granites in the Connors and western Auburn Arches was synchronous with the Kanimbla Movement, while episodes of igneous intrusion in the Late Permian, from Mar...

Ten new species of Haliotrema (Monogenoidea: Dactylogyridae) from Australian fish and a revision of the genus

Abstract: Ten new species of Haliotrema from Australian fish are described and figured: H. cteno-chaetisp. n. from Ctenochaetus strigosus; H. falcanalissp. n. from Triacanthus falcanalis; H. lineatesp. n. from Acanthurus lineatus; H. chrysotaeniaesp. n. from Lutjanuschrysotaenia; H. cromileptissp. n. from Cromileptis altivelis; H. epinephelisp. n. from Epinephelus merra and E. fasciatus; H. holocentrisp. n. from Holocentrus ruber; Haliotrema chrysostomisp. n. from Lethrinus chrysostomus and Plectorhinchus pictus; H. fletisp. n. n. from L. fletus and L. chrysostomus; H. scarisp. N. from Scarus fasciatus. H. dempsteri (Mizelle & Price, 1964) comb. n. from Acanthrus mata, A. dussumieri and A. xanthopterus: H. johnii (Tripathi, 1959) comb. n. from Lutjanus johni and L. fulviflamma: H. parahaliotrema (Mizelle & Price, 1964) comb. n. from Zebrasoma veliferum and A. grammoptilus: and H. obesa (Caballero, Bravo Hollis & Grocott, 1955) comb. n. from Tetraodon hispidus are redescribed and transferred from the genera Parahaliotrema Mizelle & Price, 1964, Ancyrocephalus Creplin, 1839, Parahaliotrema, and Tetrancistrum Goto & Kikuchi, 1917 respectively. H. brevis (Mizelle & Price, 1964) comb, n., H. canescens (Mizelle & Price, 1964) comb. n. and H. zanclus (Mizelle & Price, 1964) comb. n. are transferred from Pseudohaliotrema Yamaguti, 1953; H. eilatica (Paperna, 1965) comb. n., H. teuthis (MacCallum, 1915) comb. n., H. triacantha (Tripathi, 1959) comb. n. and H. lethrini (Yamaguti, 1937) comb. n. are transferred from Ancyrocephalus Creplin, 1839. The generic diagnosis is emended to include the above-mentioned species and the taxonomy of the genus is discussed and the formation of six species groups is proposed.

A new species of Angiostrongylus in an Australian rat, Rattus fuscipes.

Abstract: A survey of lungworm infection in rats in Queensland has shown that 23% of Rattus norvegicus, 6·5% of R. rattus 4·5% of R. fuscipes and 0% of Melomys cervinipes were infected with lungworms. Detailed examination of the lungworms revealed that there are two distinct species; one is Angiostrongylus cantonensis which was found to occur in R. norvegicus and R. rattus, the other is a new species, namely, A. mackerrasae, which was found in R. fuscipes in an area of rainforest near Brisbane. Some R. norvegicus in Brisbane also harboured A. mackerrasae. The two species were distinguished by the length of the spicules, relative length and appearance of the postero-lateral ray in the male, the presence of a minute projection at the tip of the tail in the female, length of the vagina and the distance between anus and vulva. The first-stage larvae of the two species were found to be identical. As this species has been found to be the only lungworm in R. fuscipes which is an indigenous Australian rat, it is suggested that A. mackerrasae may have originated in the Australian region.I wish to express my sincere gratitude to Professor J. F. A. Sprent and Dr L. R. Ash for their advice and encouragement during this study. Special thanks are also due to Miss M. Cremin for her assistance and to Mr H. Lavery for providing specimens from North Queensland. This work was supported by a grant from the U.S. Department of Health, Education and Welfare No. A 107023–02.

Two-dimensional flow under gravity in a jet of viscous liquid

Abstract: This paper is concerned with the steady, symmetric, two-dimensional flow of a viscous, incompressible fluid issuing from an orifice and falling freely under gravity. A Reynolds number is defined and considered to be small. Due to the apparent intractability of the problem in the neighbourhood of the orifice, interest is confined to the flow region below the orifice, where the jet is bounded by two free streamlines. It is assumed that the influence of the orifice conditions will decay exponentially, and so the asymptotic solutions sought have no dependence upon the nature of the flow at the orifice. In the region just downstream of the orifice, it is expected that the inertia effects will be of secondary importance. Accordingly the Stokes solution is sought and a perturbation scheme is developed from it to take account of the inertia effects. It was found possible only to express the Stokes solution and its perturbations in the form of co-ordinate expansions. This perturbation scheme is found to be singular far downstream due to the increasing importance of the inertia effects. Far downstream the jet is expected to be very thin and the velocity and stress variations across it to be small. These assumptions are used as a basis in deriving an asymptotic expansion for small Reynolds numbers, which is valid far downstream. This expansion also has the appearance of being valid very far downstream, even for Reynolds numbers which are not necessarily small. The method of matched asymptotic expansions is used to link the asymptotic solutions in the two regions. An extension of the method deriving the expansion far downstream, to cover the case of an axially-symmetric jet, is given in an appendix.

The actions of caerulein on gastric secretion of the dog and the rat

Abstract: 1. Caerulein, as expected from its amino-acid composition and sequence, has a potent stimulant action on gastric secretion in the dog, the rat and the frog. 2. In the denervated fundic pouch of the dog, caerulein increases the rate of flow of gastric juice and the outputs of acid and pepsin. Acid concentration and pepsin concentration in caerulein-produced juice are generally greater than in control juice. The threshold subcutaneous dose of caerulein is 0.15-0.5 μg/kg and the threshold rate of intravenous infusion 0.25-0.5 μg/kg per hr. Rapid intravenous injection is ineffective. On a molar basis, caerulein is approximately twice as active as human gastrin I on volume and acid output of the gastric pouch and 4 times as active on pepsin output. 3. Sustained acid secretion of the fundic pouch produced by histamine infusion is inhibited by caerulein, administered either intravenously or subcutaneously. In turn, acid secretion elicited by caerulein is inhibited by atropine. 4. In the rat, the activity ratio of caerulein to human gastrin I is 7-30, calculated on a molar basis, and is thus considerably greater than in the dog. Further, caerulein is 3 times more active than cholecystokinin-pancreozymin. Tested on the perfused stomach preparation of the rat, the threshold dose of caerulein by rapid intravenous injection is 25 ng/kg, by intravenous infusion 0.25 μg/kg per hr, and by subcutaneous injection 0.25 to 0.5 μg/kg. 5. The activity of caerulein is sharply reduced by pretreatment of the rats with the histamine liberator 48/80 and potentiated by pretreatment with the diamine oxidase inhibitor aminoguanidine. When caerulein is given by rapid intravenous injection during a priming infusion of histamine its effect is enhanced and considerably prolonged. 6. The isolated mucosa of the frog stomach is extremely sensitive to caerulein which, in a concentration of a few pg/ml., stimulates active transport of chloride. 7. Qualitative and quantitative differences in the action of gastrin and caerulein are pointed out, and particular emphasis is laid on the importance of esterification of the tyrosyl residue for the biological activity of caerulein.

Indospicine, a new hepatotoxic amino-acid from Indigofera spicata.

Abstract: Indigofera spicata Forsk (previously I. endecaphylla Jacq.) would be a useful tropical pasture legume without its toxic properties (for review, see ref. 1). It has been shown to be hepatotoxic to sheep, cows and rabbits, and has caused abortion in pregnant animals2. Hutton et al.3,4 showed that the leaf and seed were hepatotoxic to rabbits and mice and that β-nitropropionic acid, which occurs only in the leaf, did not account for these liver lesions. Britten et al.5 found that β-nitropropionic acid or a compound closely associated with it in the leaf was toxic to chicks, which were not affected by the hepatotoxin(s) present in the seed.

The clinical differentiation of lead gout from primary gout.

Abstract: A group of gouty patients with renal disease following lead poisoning in childhood was compared with another group of gouty patients in whom a lead etiology could be excluded. Comparison revealed that the lead gout group contained a higher proportion of women, half of whom were premenopausal. The lead gout group also showed a greater incidence of renal disease in kindred, of hypertension in siblings, and sequelae of acute lead encephalopathy in the form of mental impairment and euphoria. The severity and the number of attacks of acute gouty arthritis, however, was less in the lead gout group. Renal disease was invariable in lead gout and antedated the gouty arthritis. Features occurring more frequently in the primary gout group were regular alcohol consumption, obesity and renal calculi. These findings confirm previously reported features of primary gout and provide pointers to a possible lead etiology in other gouty patients.

Spores from a Carboniferous section in the Hunter Valley, New South Wales

Abstract: In this initial systematic study of Carboniferous spores from New South Wales, Australia, fifteen species (all but one of them new) are formally described and are distributed among eight established genera and two new genera (Rattiganispora, a distally annulate trilete form, and Psomospora, an inaperturate or proximally hilate form). The species were selected as being the most characteristic and distinctive forms found in the Italia Road Formation at its well‐exposed type section in the Hunter Valley, east‐central New South Wales. The formation is a cyclical non‐marine unit, over 300 metres (1,000 ft) thick, consisting of lithic arenites together with carbonaceous shales, claystones, and siltstones; its age is regarded as West‐phalian‐Stephanian. The microfiora is compared with those known from sediments of similar age elsewhere and its place in the Australian Palaeozoic palynostratigraphic record is discussed. New specific institutions are as follows: Punctatisporites lucidulus, P. sub‐tritus, V...

Plant enzyme synthesis: Hormonal regulation of invertase and peroxidase synthesis in sugar cane.

Abstract: Using sugar-cane internodal tissue in which RNA synthesis was ratelimiting for invertase of peroxidase synthesis, measurements were made of enzymeforming-capacity after blocking further RNA synthesis with actinomycin D or 6-methylpurine. In this way it was possible to determine whether added auxin (naphthaleneacetic acid) or gibberellic acid (GA3) affected steps prior or subsequent to synthesis of the RNA fractions specifically required for synthesis of either enzyme. Both auxin and GA3 increased the enzyme-forming-capacity for invertase but not for peroxidase. The effects of the two hormones are interpreted as causing stabilization of mRNA for invertase.Abscisic acid (ABA) increased the rate of synthesis of invertase but not peroxidase. ABA did not change the rate of loss of invertase when peptide-bond formation was blocked with cycloheximide, but stimulated its synthesis when RNA synthesis was blocked with 6-methyl purine. Hence, the site of action of ABA is subsequent to invertase-mRNA formation and prior to invertase destruction.Kinetin had no short-term effects when RNA synthesis was limiting for invertase production, and does not appear to directly modulate mRNA synthesis or stabilization, or amino-acid-polymerization steps. In treatments longer than 5 hours, kinetin inhibited synthesis of all three enzymes studied, so that its effect on enzyme synthesis in this tissue appears to be unspecific.

Variation in ferrous iron-magnesium distribution coefficients of metamorphic pyroxenes from Quairading, Western Australia

Abstract: Distribution coefficients (KD·Fe++-Mg) calculated for orthopyroxene-clinopyroxene pairs from 12 basic granulites of the Quairading district, Western Australia, range from 1.87 for magnesian pyroxenes (Opx Mg value=78.1) to 1.70 for iron-rich varieties (Opx Mg value 37.7). Field and petrographic evidence indicates that these pyroxenes have probably reached equilibrium within a narrow temperature range. In order to account for the observed variation of KD values it is suggested that one (or both) of the pyroxene structures is not the ideal Fe++-Mg "solution" proposed in the thermodynamic model of the pyroxene equilibrium exchange. After consideration of the geometry of the pyroxene cation sites, the relative bond energies of each site (especially crystal field stabilization energy) and structural ordering a model is proposed to explain the non-ideal behaviour of Fe++-Mg in the pyroxene system. The distribution pattern in low-iron pyroxenes will probably show Fe++ favouring the M2·Opx site; competing unfavourably with Mg++ for the M1·Cpxsite; and probably excluded by Mg++ from the M1·Opxsite. As the iron content of the system increases the M2·Opxsite will begin to become saturated with Fe++ and this ion will enter the M1·Opx site. Further increases in the iron content of the system will cause the Fe++-Mg distribution to depend increasingly on the relative attraction of the M1 sites of both pyroxenes. Of these sites Fe++ should show preference to the more distorted M1·Cpxsite. The distribution coefficient reflects this swing towards a relative enrichment of Fe++ in the clinopyroxene by decreasing regularly with increasing iron content. It is likely that this downward trend will not become evident until the iron content of the M2·Opx site reaches saturation. This would explain why the KD values for the magnesian pyroxenes remain practically unchanged until the orthopyroxene Mg value is approximately 60; from here on the iron-rich pyroxenes show a rapid decrease in KD value with increasing iron content. The Ca content of the pyroxenes is also significant since the Quairading pyroxenes show a marked increase in mutual solubility with increasing iron content. Calcium taken into the orthopyroxene structure will enter the M2 site ahead of Fe++ so that this site will reach Fe++ saturation at a lower iron content than when the orthopyroxene is Ca-free. The application of KD values to the regional study of basic granulites, particularly when establishing relative temperature zones on the basis of KD variation, should only be attempted when pyroxenes which extend over a wide range of Fe-Mg content are available.

Variation with age and sex in strength of the femur

Abstract: Variation in dimensions and mechanical properties of the femur was examined in relation to variation in age and sex of the subject. One hundred and forty-five fresh, adult femora were studied. Mean values are given of the breaking load of the femur and the tensile strength of the femoral compact bone for members of each sex. The mean breaking load of the femora of female subjects is less than that of male subjects, and it is concluded that this difference is due to the smaller dimensions of the female skeleton; mechanical deterioration of bone tissue is responsible for reduction in strength of the femur with increasing age of the subject. It is suggested that factors other than increase in porosity are responsible for reduction in tensile strength of compact bone.