Biomedical subjects

G P Jones

Publications and source records attributed to G P Jones.

At least 19 recordsLinked to original sources

PubMed2003

Functional capabilities of modern and fossil hominid hands: three-dimensional analysis of trapezia.

Three-dimensional (3D) trapezium models from Homo sapiens, Gorilla gorilla, Pan troglodytes, Australopithecus afarensis (A.L.333-80), and Homo habilis (O.H.7-NNQ) were acquired through laser digitizing. Least-square planes were generated for each articular surface, and the angles between the planes were compared. Each extant species displays an overall pattern that distinguishes it from the others. The observed angles in G. gorilla and P. troglodytes are more similar to one other than either is to H. sapiens. Our results, obtained from using new 3D modeling and analytical tools, raise interesting questions about the functional capabilities of the fossil trapezia. Multivariate statistical analyses indicate that A.L.333-80 is morphologically more similar to that of modern humans, whereas the O.H.7 trapezium is more similar to that of the gorilla. Significant differences between A.L.333-80 and the extant species occur, but some similarities to humans suggest the ability to form the distinctively human forceful pad-to-side and three-jaw chuck grips. Some key morphological differences from humans highlighted and quantified by our research suggest limitations in the functional capabilities of the O.H.7 trapezium, particularly in those that facilitate pronation at the base of the second metacarpal. If the O.H.7 trapezium represents part of the hand responsible for manufacturing and using the stone tools found at Olduvai, our results suggest that the hand manipulated the stones in a way for which we have no modern analog. Alternative considerations are that the O.H.7 trapezium is not representative of other trapezia from its species (i.e., N=1), or that it represents another primate or hominid species.

Animals↗

PubMed2001

Analysis of proanthocyanidin cleavage products following acid-catalysis in the presence of excess phloroglucinol.

The analysis of proanthocyanidin cleavage products after acid-catalysis in the presence of excess phloroglucinol was investigated. In the developed analytical method, a solution of 0.1 N HCl in methanol, containing 50 g/L phloroglucinol and 10 g/L ascorbic acid was prepared. The proanthocyanidin of interest was reacted in this solution (5 g/L) at 50 degrees C for 20 min, and afterward combined with 5 volumes of 40 mM aqueous sodium acetate before analysis by reversed-phase HPLC using an aqueous acetic acid and methanol gradient. This procedure was used to investigate the composition of proanthocyanidins isolated from the seed and skin tissue of Vitis vinifera L. berries. The results compared favorably to results obtained when benzyl mercaptan was used as the trapping nucleophile, indicating that phloroglucinol is an effective reagent for this analysis.

Anthocyanins↗

PubMed2001

Composition of grape skin proanthocyanidins at different stages of berry development.

The composition of grape (Vitis vinifera L. cv. Shiraz) skin proanthocyanidins has been determined at different stages of berry development. Beginning approximately 3 weeks after fruit set and concluding at commercial ripeness, the composition of isolated skin proanthocyanidins was determined using the following analytical techniques: elemental analysis, UV-Vis absorption spectroscopy, reversed-phase HPLC after acid-catalysis in the presence of excess phloroglucinol, gel permeation chromatography, electrospray ionization mass spectrometry (ESI-MS), and (13)C NMR. On the basis of these analyses, berry development was correlated with an increase in proanthocyanidin mean degree of polymerization, an increase in the proportion of (-)-epigallocatechin extension subunits, and increases in the level of anthocyanins associated with the proanthocyanidin fraction. Additionally, data acquired from ESI-MS of the isolates following acid-catalysis in the presence of excess phloroglucinol is consistent with pectin-bound proanthocyanidins.

Anthocyanins↗

PubMed2001

Isolation and structures of oligomeric wine pigments by bisulfite-mediated ion-exchange chromatography.

Methods have been developed that are based on cation exchange chromatography in the absence and presence of excess bisulfite for the isolation of wine pigments from Australian red wine and grape marc extract. The pigments were identified using HPLC and electrospray ionization mass spectrometry. The mass spectral data indicate that these pigments are C4-substituted anthocyanins with a tetracyclic structure. The pigments form a series of closely related oligomeric pigments which include those previously described in the literature, such as pigment A and vitisin A, as well as some newly identified pigments.

Chromatography, Ion Exchange↗

PubMed2001

The incorporation of whole grain into pelleted broiler chicken diets: production and physiological responses.

1. Pelleted diets, incorporating whole or ground triticale or wheat in the pellets, were fed to broiler chickens and the performance, gastro-intestinal development and health of those chickens recorded. 2. The use of whole triticale in the pelleted food produced similar bodyweight responses to when ground triticale was incorporated in the food. Food conversion efficiency was enhanced when whole triticale was used compared to ground triticale and was similar to when an exogenous enzyme was added to the ground triticale diet. The incorporation of whole wheat into the pelleted food produced similar production responses to the use of ground wheat. 3. The gastro-intestinal development of the birds was greater when they were fed the whole grain diet as gizzard weights were increased by the incorporation of whole grain into the diet. Gastro-intestinal development was thought to be related to the presence of large fibre particles in the food. 4. Proventricular dilatation and mortality due to ascites were reduced by feeding pelleted diets containing whole grain, which was possibly related to the early development of the gastro-intestinal tract relative to total body development. 5. It is suggested that the current use of exogenous enzyme additions to broiler diets may be reduced by incorporating whole grain into pelleted diets for broiler chickens.

Animal Feed↗

PubMed2001

Temporary monocular blindness associated with acute carotid thrombosis: a case report.

We report upon a patient with multiple, progressive episodes of temporary monocular blindness associated with acute thrombosis and a critical internal carotid artery stenosis. Carotid angiography demonstrated an anatomically compelling situation consisting of a critical reduction of flow distal to a preocclusive internal carotid artery stenosis accompanied by intraluminal thrombus. The patient was managed successfully by urgent thrombectomy and carotid endarterectomy. This case report highlights principles in management of patients with the unstable neurologic condition of temporary monocular blindness associated with an anatomically compelling situation demonstrated on angiography.

Acute Disease↗

PubMed2000

Changes to the quantity and processing of starchy foods in a western diet can increase polysaccharides escaping digestion and improve in vitro fermentation variables.

This study investigated how readily achievable changes to the quantity and processing of starchy foods in a typical Western diet: (1) were reflected in levels of resistant starch (RS) and NSP excreted from the small intestine; and (2) more favourable profiles of butyrate, NH3 and phenol production. Two diets, a low-starch diet (LSD) and a high-starch, low-fat diet (HSLFD) were compared. The LSD with 20% total energy (%E) from starch was based on a 'typical' Australian diet, while the HSLFD (40%E as starch) was the same Australian diet modified by an increased content of legumes, starchy foods and coarsely-ground cereals and by a reduced fat content. Four subjects with iliostomies consumed each diet for 2 d, with ileal effluent collection on the second day. On the HSLFD compared with the LSD, RS in ileal effluent increased from from 0.49 to 1.7 g/MJ per d (P < 0.005) while ileal NSP excretion increased from 2.0 to 3.3 g/MJ per d (P < 0.05). Ileal effluents obtained after each diet were incubated for 24 h in vitro with a human faecal innoculum. After fermentation, ileal effluent from the HSLFD produced more butyrate relative to other short-chain fatty acids (17.5 v. 15.8 molar %, P < 0.005) and less phenol (2.3 v. 5.7 mg/l, P < 0.05) and NH3 (20.3 v. 23.1 mmol/l, P < 0.005) than the LSD diet. The HSLFD also generated a lower pH (6.15 v. 6.27, P < 0.05). On a wt/wt basis, RS was 2.3-fold higher in the HSLFD effluent while NSP did not increase, suggesting that the change in RS largely contributed to the fermentation effects. Changes in in vitro variables when the HSLFD ileal effluent was ground before fermentation indicated the importance of physical structure in determining ileal excretion of RS. We conclude that: (1) readily achievable modifications to the amount and processing of starchy foods in an Australian diet would produce potential benefits for in vitro fermentation variables; and (2) the physical structure of grains and cereals is important in determining access by colonic bacteria to a carbohydrate substrate.

Adolescent↗

PubMed2000

Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: their release during fermentation and lees contact and a proposal for their mechanism of action.

A fraction containing the mannoproteins released during fermentation from the winemaking strain of Saccharomyces cerevisiae, Maurivin PDM, was able to reduce the visible protein haze in white wine. This fraction of haze protective mannoprotein material (HPM) could be recovered by either ultrafiltration or ethanol precipitation. The kinetics of the release of both mannose- and glucose-containing polymers during the growth cycle of PDM were determined as a guide to the release of HPM. Active HPM was first detected in the culture supernatant when the cells were exponentially growing. HPM was also released into the medium under an environment simulating winemaking conditions by PDM cells during fermentation as well as during storage on yeast lees. Since the amounts of HPM released during fermentation are greater than those subsequently extracted from the cell wall, fermentation would be a more viable procedure than extraction from yeast cells for the commercial production of HPM. Yeast invertase, a mannoprotein with haze protective activity, was used as a model substrate to investigate the mechanism of haze protection. Invertase was found to reduce visible turbidity but not prevent protein precipitation. Invertase itself did not precipitate but remained soluble in the wine. On the basis of these observations, we propose that the mechanism of haze protection may be one of competition between HPM and wine proteins for unknown wine component(s), the latter being required for the formation of large insoluble aggregates of denatured protein. As the available concentration of these components decreases, due to the presence of HPM, the particle size of the haze decreases and thus visible turbidity declines.

Fermentation↗

PubMed2000

Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: evaluation of extraction methods and immunolocalization.

Yeast-derived haze-protective mannoprotein material (HPM) offers protection to white wines from commercially unacceptable turbidities. HPM extraction methods have been evaluated using three winemaking strains of Saccharomyces cerevisiae. Digestion with Zymolyase of cells pretreated with DTE and EDTA gave the greatest yields of active material. Heat treatment of cells with SDS also released active material but the quantities were low. Treatment of the cells in an autoclave or with a French pressure device was less effective. A detailed study was conducted on the strain Maurivin PDM. SDS was not necessary to extract HPM from PDM; boiling the cells for 5 min in Tris buffer was sufficient. HPM could also be extracted with EDTA during the pretreatment of the cells prior to Zymolyase digestion. The data suggest that HPM was noncovalently linked to other cell wall components and loosely associated with the cell wall. An immunological investigation showed that a specific mannoprotein with haze-protective activity, HPF1, was located primarily on the outermost and innermost layers of the cell wall.

Food Handling↗

PubMed2000

Influence of the method of calcium provision on Marek's disease losses in compound and choice fed layers.

1. Two strains of layers were fed compound or choice forms of a standard diet and given calcium as either ground limestone or coarse limestone grit daily or every 2nd day. Mortality caused by Marek's disease was monitored during the rearing and laying phases. 2. A dramatic difference in Marek's disease mortality was found between the strains. Heavy Marek's disease mortality in the imported strain A in the rearing phase was not markedly affected by dietary or calcium treatment. 3. Method of feeding and calcium provision interacted to influence significantly the risk of death due to Marek's disease in the laying phase in layer strain A. 4. Choice feeding may adversely influence Marek's disease losses in layers.

Animal Feed↗

PubMed2000

Radiation protection consequences of the care of a terminally ill patient having received a thyroid ablation dose of 131I-sodium iodide.

The death of a patient soon after an ablation dose of 131I-sodium iodide is a rare occurrence. We report a case of a patient who died, following emergency surgery to treat gastric bleeding, whilst still radioactive. The doses received by clinical staff involved in management of the patient were measured and were found to be within acceptable limits. However, there was an appreciable level of unsealed radioactivity in the Intensive Care Unit. The issues raised by this case are discussed in the context of legislative requirements and the worst case scenario. The event highlights the need for close liaison between the different specialities to ensure that clinical staff are properly advised and that necessary safety precautions are taken to avoid compromising the safety of staff or the care of the patient.

Fatal Outcome↗

PubMed1999

Determination of oak lactones in barrel-aged wines and in oak extracts by stable isotope dilution analysis.

The cis- and trans-isomers of 5-butyl-4-methyl-4,5-dihydro-2(3H)-furanone, the so-called oak lactones, are derived from oakwood, and the cis-isomer is an important contributor to wine flavour. Their deuterium-labelled forms, [2H4]cis-oak lactone and [2H4]trans-oak lactone, were synthesised from the unlabelled analogues, and were utilised in a new method employing gas chromatography-mass spectrometry to determine the concentration of these compounds in wine or extracts of oak shavings in a single analysis. The method can employ either liquid-liquid extraction or solid-phase microextraction, and is both rapid and accurate. There was some artefactual generation of cis-oak lactone during the analysis of model wine extracts of unheated oak shavings when diethyl ether extraction and injector block temperatures at or above 225 degrees C were employed.

Gas Chromatography-Mass Spectrometry↗

PubMed1999

Chronic lung injury in preterm lambs. Disordered respiratory tract development.

The cause of chronic lung disease of early infancy, often called bronchopulmonary dysplasia (BPD), remains unclear, partly because large-animal models that reliably reproduce BPD have not been available. We developed a model of BPD in lambs that are delivered prematurely and ventilated for 3 to 4 wk after birth to determine whether the histopathology of chronic lung injury in premature lambs mimics that which occurs in preterm infants who die with BPD, and to compare two ventilation strategies to test the hypothesis that differences in tidal volume (VT) influence histopathologic outcome. The two ventilation strategies were slow, deep ventilation (20 breaths/min, 15 +/- 2 ml/kg body weight VT; n = 5) or rapid, shallow ventilation (60 breaths/min, 6 +/- 1 ml/kg body weight VT; n = 5). Lambs were delivered at 125 +/- 4 d gestation (term = 147 d), treated with surfactant, and mechanically ventilated with sufficient supplemental oxygen to maintain normal arterial oxygenation (60 to 90 mm Hg). Quantitative histologic analysis revealed lung structural abnormalities for both groups of experimental lambs compared with lungs of control term lambs that were < 1 d old (matched for developmental age; n = 5) or 3 to 4 wk old (matched for postnatal age; n = 5). Compared with control lambs, chronically ventilated preterm lambs had pulmonary histopathology characterized by nonuniform inflation patterns, impaired alveolar formation, abnormal abundance of elastin, increased muscularization of terminal bronchioles, and inflammation and edema. Slow, deep ventilation was associated with less atelectasis, less alveolar formation, and more elastin when compared with rapid, shallow ventilation. We conclude that prolonged mechanical ventilation of preterm lambs disrupts lung development and produces pulmonary histopathologic changes that are very similar to those that are seen in the lungs of preterm infants who die with BPD. This chronic lung disease is not prevented by surfactant replacement at birth, does not appear to require arterial hyperoxia, and is influenced by VT.

Animals↗

PubMed1998

The synergistic preservative effects of the essential oils of sweet basil (Ocimum basilicum L.) against acid-tolerant food microflora.

Essential oils extracted by hydrodistillation from five different varieties of Ocimum basilicum L. plants (Anise, Bush, Cinnamon, Dark Opal and a commercial sample of dried basil) were examined for antimicrobial activity against a wide range of foodborne Gram-positive and -negative bacteria, yeasts and moulds by an agar well diffusion method. All five essential oils of basil showed antimicrobial activity against most of the organisms tested with the exception of Flavimonas oryzihabitans and Pseudomonas species. The inhibitory effect of Anise oil, in comparison with mixtures of the predominant components of pure linalool and methyl chavicol, against the acid-tolerant organisms, Lactobacillus curvatus and Saccharomyces cerevisiae, was examined in broth by an indirect impedance method. Synergistic effects between Anise oil, low pH (pH 4.2) and salt (5% NaCl) were determined. The antimicrobial effect of Anise oil was also assessed in a tomato juice medium by direct viable count, showing that the growth of Lact. curvatus and S. cerevisiae was completely inhibited by 0.1% and 1% Anise oil, respectively. The results of the current study indicate the need for further investigations to understand the antimicrobial effects of basil oils in the presence of other food ingredients and preservation parameters.

Acyclic Monoterpenes↗

PubMed1997

Dietary intake and faecal excretion of carbohydrate by Australians: importance of achieving stool weights greater than 150 g to improve faecal markers relevant to colon cancer risk.

OBJECTIVES: This study investigated, on 53 Australians consuming a typical Western diet, the relationship between dietary intake, faecal excretion of carbohydrate and changes in faecal markers believed to be relevant to colon cancer risk, for example faecal output, transit time and concentrations of phenols, ammonia and butyrate. DESIGN: Fifty-three subjects consuming their usual diet were asked to record and weigh all food consumed for a seven day period, and to collect faeces for three days during this period. SETTING: Geelong, Victoria, Australia. SUBJECTS: All volunteers were either staff and students of the university, or associates of the authors. INTERVENTIONS: None. RESULTS: Volunteers had the following dietary intakes of carbohydrate (g/d; mean +/- s.d.); starch 131 +/- 41 (including resistant starch (RS), 5 +/- 2), sugar 108 +/- 37 and non-starch polysaccharides (NSP) 14 +/- 7. Daily faecal output was 127 +/- 70 g and transit time 47 +/- 19 h. Analysis of faecal samples found 0.8 +/- 1.2 g RS and significant relationship with the concentration (mmol/L) of butyrate excreted n faeces (r = 0.34, P < 0.05). Dietary intake of RS was associated with higher concentrations of faecal ammonia (r = 0.34, P < 0.05), but this association was reversed when RS was combined with NSP in the diet (r = 0.07, NS). In contrast to dietary intake, the faecal excretion of RS was negatively related to faecal ammonia concentration (r = -0.40, P < 0.01) and positively related to faecal output (r = 0.64, P < 0.01). Individuals who consumed more NSP in their diet (19 +/- 7 g/d) excreted more than 150 g faeces per day and had higher quantities of faecal-RS and -NSP; faster transit times; higher concentrations of short chain fatty acids and lower concentrations of potentially harmful ammonia and phenols. CONCLUSIONS: The combination of RS and NSP in the colon may be required to achieve an optimal luminal environment conducive to 'colonic health'. The results also support the suggestion that faecal output (< or > 150 g/d) may provide a useful index of colon cancer risk. High faecal outputs are achieved through higher intakes of NSP (the major component of dietary fibre).

Adolescent↗

PubMed1996

Barley beta-D-glucan exohydrolases with beta-D-glucosidase activity. Purification, characterization, and determination of primary structure from a cDNA clone.

Two beta-glucan exohydrolases of apparent molecular masses 69,000 and 71,000 Da have been purified from extracts of 8-day germinated barley grains and are designated isoenzymes ExoI and ExoII, respectively. The sequences of their first 52 NH2-terminal amino acids show 64% positional identity. Both enzymes hydrolyze the (1,3)-beta-glucan, laminarin, but also hydrolyze (1,3;1,4)-beta-glucan and 4-nitrophenyl beta-D-glucoside. The complete sequence of 602 amino acid residues of the mature beta-glucan exohydrolase isoenzyme ExoII has been deduced by nucleotide sequence analysis of a near full-length cDNA. Two other enzymes of apparent molecular mass 62,000 Da, designated betaI and betaII, were also purified from the extracts. Their amino acid sequences are similar to enzymes classified as beta-glucosidases and although they hydrolyze 4-nitrophenyl beta-glucoside, their substrate specificities and action patterns are more typical of polysaccharide exohydrolases of the (1,4)-beta-glucan glucohydrolase type. Both the beta-glucan exohydrolase isoenzyme ExoI and the beta-glucosidase isoenzyme betaII release single glucosyl residues from the nonreducing ends of substrates and proton-NMR shows that anomeric configurations are retained during hydrolysis by both classes of enzyme. These results raise general questions regarding the distinction between polysaccharide exohydrolases and glucosidases, together with more specific questions regarding the functional roles of the two classes of enzyme in germinating barley grain.

Amino Acid Sequence↗

PubMed1995

Simple high-performance liquid chromatographic analysis of phenol and p-cresol in urine and feces.

Previous reports which present methods of analysis of phenol and p-cresol by HPLC are usually designed for the detection of these compounds in urine, can be complicated by the use of uncommon equipment or additional techniques such as steam distillation or derivatisation, or concentrate on the detection of phenol rather than p-cresol. In this paper we report a simple method suitable for the analysis of phenol and p-cresol in both urine and feces, based upon extraction into ether following acid hydrolysis and UV detection.

Chromatography, High Pressure Liquid↗

PubMed1995

Response of broilers susceptible to ascites when grown in high and low oxygen environments.

1. Broilers selected on the basis of food conversion efficiency or growth rate were grown under normal (21%) or varied (19%, 23%) oxygen environments. 2. Broilers selected for food conversion efficiency had greater growth rates and superior food conversion efficiencies than broilers selected for growth rate. No interactions between broiler strain and oxygen level were observed. 3. Increasing environmental oxygen level decreased N efficiency in both broiler strains. Nitrogen turnover was non-significantly decreased. 4. Ascites may only occur when broilers are able to cope with small environmental adversities while maintaining optimal growth rates.

Animals↗