Direct transesterification of lipids from feedstuffs and ruminal bacteria

Direct transesterification of feedstuffs, browse plants, and ruminal bacteria was compared to transesterification of solvent extracted lipids. Weight percentages were of similar magnitude between procedures. Direct transesterification often produced higher concentrations of fatty acids. Results indicate that direct transesterification is an acceptable method for analysis of total fatty acids. Key words: Transesterification, lipids, feedstuffs, bacteria

Fatty acid composition and cholesterol concentration in tissues of white-tailed deer (Odocoileus virginianus) as influenced by lactation, age, and season of the year

The purpose of this study was to determine effects of lactation, season, and age on fatty acid compositions of adipose tissue (subcutaneous and perirenal), liver, and muscle (m. longissimus dorsi), and on cholesterol concentration of liver and muscle, of female white-tailed deer (Odocoileus virginianus). Lactation did not affect fatty acid composition in adipose tissue or muscle, but in liver, weight percentages of 18:2 were lower, and of 20:4 higher in non-lactating does. Increased age (fawns, yearlings, 2 and 3+(-)years old) decreased 14:0, 15:0, and 16:0 in subcutaneous adipose tissue; decreased 14:0, 15:0, 16:1, 18:2, and increased 18:0 in perirenal adipose tissue; increased 18:1 and decreased 18:2 in liver; and increased 18:1, 18:3, and 20:4, and decreased 18:2 in muscle. Season of the year had little effect on adipose tissue and muscle fatty acids. Liver of fall season does had greater concentrations of most fatty acids than winter does, and cholesterol concentration was greatest in liver of winter does. It was concluded that season and lactation minimally affect fatty acid composition in adipose and muscle, whereas changes in saturated and unsaturated fatty acids occur with increased age. Also, liver fatty acids are influenced by each parameter studied, but cholesterol varies only with season.

Influence of sire growth potential, time on feed, and growing-finishing strategy on cholesterol and fatty acids of the ground carcass and longissimus muscle of beef steers

The purpose of this study was to determine how diverse beef cattle production systems affect fatty acids and cholesterol of meat. Crossbred cows were bred by AI to high (H) or moderate (M) growth rate potential bulls to produce spring- or fall-born calves. Steer calves from these matings were placed on finishing diets at three ages. Spring-born steers were started at 6 or 18 mo of age (A6 and A18), and fall-born calves were started at 12 mo of age (A12). Slaughter times were 0, 90, 180, and 270 d for A6; 68, 136, and 204 d for A12; and 0, 45, 90, and 135 d for A18. Four steers of each type were slaughtered in each of 2 yr for each sire type x time on feed x slaughter group. Fatty acids and cholesterol of ground carcass and longissimus muscle (LM) were determined by GLC. Carcass fat increased faster in M than in H steers (P < .01). Ground carcass cholesterol was greater for M steers (P = .06) than for H steers because of the greater fat content in the M ground carcass. No differences in LM cholesterol were observed for sire growth potential or time on feed. Fatty acid differences in ground carcass with time on feed were due primarily to decreases in 18:0 and increases in 18:1. The LM saturated and monounsaturated fatty acids changed little with time on feed, but total saturates were greater for M steers (44.5%) than for H steers (42.8%) (P = .02). A18 steers of H sires had the greatest (P = .04) ratio of 18:0 plus unsaturates to 14:0 plus 16:0 (most hypocholesterolemic). We conclude that cholesterol in lean muscle is not altered by the sire growth potential x time on feed x growing-finishing strategy imposed, and that lean beef from steers sired by H bulls and backgrounded before finishing may produce meat with the healthiest lipid composition.

Adenomatoid odontogenic tumour in a 12-year-old boy

We present a rare finding of adenomatoid odontogenic tumour (AOT) in a 12-year-old boy who was referred to the Department of Paediatric Dentistry at the Eastman Dental Hospital for the extraction of a carious maxillary permanent molar. First presentation revealed that the maxillary right permanent lateral incisor and canine were unerupted. Radiological examination revealed a circumscribed radiolucent area associated with the distal aspect of the maxillary right permanent lateral incisor. The patient was admitted to our Day Care Unit where the carious maxillary molar was extracted and the radiolucent area associated with the maxillary right permanent incisor was explored. Pathological examination confirmed the lesion as adenomatoid odontogenic tumour. We present a brief review of the literature and consider how differential diagnosis of this tumour from more common odontogenic lesions can be established.

Multiple supernumeraries: the importance of clinical and radiographic follow-up

The occurrence of multiple supernumerary teeth is a rare phenomenon. Three cases of multiple supernumeraries are presented which illustrate problems which may arise during long-term follow-up: resorption of adjacent teeth, enlargement of the follicles, movement of the unerupted teeth and development of further supernumeraries. These cases highlight the importance of adequate initial surveillance, anticipation of potential problems, assessing the risk-benefits of surgery and long-term monitoring, in some cases following the surgical removal of supernumeraries.

The changing pattern of day-care treatment for children in a London dental teaching hospital

Day-stay general anaesthesia facilities may be employed to provide comprehensive dental care for children who are unable to accept treatment using alternative methods of patient management. This approach to delivery of care has been shown to be cost-effective, acceptable and efficaceous. This study was set up to investigate changes in the pattern of care provided in day-care facilities at a London dental teaching hospital over a 20-year period--1972 to 1992. The results show that the use of the facilities at this centre has increased with time, with a greater increase amongst older children in recent years. Although the main use is still for the treatment of caries, oral surgery procedures, especially those related to orthodontic treatment, have increased by 200% between 1982 and 1992. This correlates with the increase in older age groups being treated. Details of mean numbers of teeth restored and extracted for each age group are presented for 1992. They indicate, for the younger age groups, not only the high treatment needs of patients referred to the hospital, but also suggest a trend for more radical treatment planning in order to avoid further general anaesthesia. Readers are reminded that, despite its advantages, general anaesthesia should be avoided if possible.

Midline supernumeraries: a family affair

Supernumerary teeth are relatively common in the general population and appear to be more likely to occur in patients with a family history of such teeth. It is important that these teeth are identified and in some cases removed before undertaking orthodontic treatment. This article describes two patients who presented with supernumeraries, and their treatment.

Effect of dietary canola on fatty acid composition of bovine adipose tissue, muscle, kidney, and liver

The purpose of this study was to determine effects of feeding canola and soybean products as protein supplements on fatty acid composition of adipose tissue and muscle of slaughter bulls and steers and on fatty acid composition of kidney and liver total lipids of bulls. Products included canola meal (CM), extruded canola (EC, full-fat), ground canola (GC, full-fat), soybean meal (SBM), and extruded soybeans (ES, full-fat). Tissues were obtained at slaughter from 75 crossbred beef bulls and 50 crossbred beef steers fed corn silage (17.2 to 29.7% of DM), ground corn (56.5 to 75.0% of DM), and protein supplements (6.8 to 21.6% of DM). The DMI was not influenced by dietary fat in either trial. Gain: feed was greater (P < .05) for bulls fed CM than for bulls fed ES, EC, or GC. Carcasses were not influenced appreciably by dietary fat. Adipose tissue of EC-fed cattle had the lowest percentage of 16:0 (P < .05, vs SBM, CM, and GC), whereas both EC- and GC-fed cattle had the highest 18:0 (P < .05). In muscle (pectoral), EC-fed bulls had a higher percentage of 18:1 than SBM-fed bulls (P < .05), and EC-fed steers had the lowest 16:0 and 16:1 and highest 18:0, 18:3, and 20:1 (P < .05). Kidney total lipids of EC- and GC-fed bulls had the lowest percentage of 16:0 and highest 18:1 and 18:3 (P < .05); bulls fed ES had the highest percentage of 18:2. Liver-lipid 16:0 was highest in ES-fed bulls and lowest in EC-fed bulls, which also had the highest 18:0 (P < .05). Bulls fed EC and GC had the highest 18:3 and 20:5 (P < .05). In conclusion, dietary full-fat canola and in some cases full-fat soybeans altered the fatty acid composition of lipids of adipose tissue, muscle, kidney, and liver of beef cattle.

The influence on partial denture design of a teaching video for general dental practitioners

This evaluation was based on replies from a random sample of general dental practitioners who were asked to complete questionnaires before and after being sent a video and accompanying booklet on partial denture design. Forty per cent (257) of the original sample (636) completed and returned both questionnaires. A total of 212 respondents (82%) felt the video had been of value and 175 (68%) said they would be more likely to provide metal partial dentures after having watched it. The positive effects of the video were greatest amongst the most recently qualified. Despite some improvement after watching the video, there remained 105 (40%) who indicated that they would leave all partial denture design decisions to the technician on at least some occasions. Comparison of data from first and second questionnaires showed little evidence of substantial shifts in choice of denture design for a series of specific situations. It was concluded that whilst the programme had been well received and had produced changes in intention, there was less objective evidence of change.

Effects of a tristearate-containing lipid and canola oil on plasma and tissue lipids in rats

Male Sprague-Dawley rats were fed semipurified diets containing 12% fat and 0.4% cholesterol for 4 wk. The fats were palm oil, a high-stearate fat and canola oil; each of the latter two fat sources was substituted for palm oil in 4% (w/w) increments (i.e, 4, 8 and 12%) thus yielding 3 stearate-containing, 3 canola-containing, and a 12% palm oil diet. Stearate-fed animals exhibited significantly decreased food efficiency ratios, plasma total cholesterol, and liver cholesterol whereas the substitution of canola for palm oil did not consistently alter these parameters. Liver fatty acids generally reflected the composition of the dietary fat sources with the exception of significantly higher arachidonate observed in the stearate-fed rats.

Effects of dietary fatty acid composition on glycerophosphate acyltransferase activity in rat adipose tissue and liver

1. How source of dietary fat influences glycerophosphate acyltransferase (GPAT) activity in homogenates of adipose tissue and liver was determined using 5 rats per diet that contained 12% fat from either corn- (CO), high-oleate-safflower (HOSO), palm- or high-stearate-oils. 2. Activity was greatest in adipose tissue homogenates of rats fed HOSO and CO whereas no treatment effects were observed in liver homogenates. 3. No differences in fat pad weights were observed; thus HOSO- and CO-diets likely depressed other lipid synthetic rates. 4. Data indicate that mono- and diunsaturated fatty acid diets supported greater adipose tissue GPAT activity than did saturated fat diets when fed to rats.

Palmitate esterification and glycerophosphate acyltransferase activity in adipose tissue of growing lambs

The purposes of this study were to determine the effects of BW in growing lambs on rates of palmitate esterification (PE) and activity of glycerophosphate acyltransferase (GPAT) in subcutaneous and intermuscular adipose tissue in vitro and to determine the relationship between these in vitro measurements and carcass lipid accretion. At 37, 49, 60, and 71 kg of live weight, nine, nine, eight, and seven Columbia-Rambouillet-cross ewe lambs, respectively, were slaughtered and adipose tissue was dissected for glycerolipid biosynthesis assays. One-half of each carcass was boned, and carcass soft tissue lipid was measured. In both adipose tissues, PE and GPAT activity were highest at 37 kg (P = .0001); the greatest accumulation of carcass fat occurred between 37 and 49 kg (P = .0001). Differences in PE and GPAT were less well marked between 49-, 60-, and 71-kg lambs, but both were generally decreased with increased BW. Significant R2 from regressions of mass and percentage of carcass fat on either PE, GPAT, or steady-state glycerolipid synthesis (GLS) were from .39 to .44 (PE), .40 to .58 (GPAT), .50 to .75 (GLS), and .60 to .77 (PE, GPAT, and GLS combined). Changes in PE, GPAT, and GLS with BW were consistent with changes in rates of carcass fat accretion, which indicated a close relationship between glycerolipid biosynthesis in vitro and lipid deposition in vivo in growing-finishing lambs.

Effect of fluoride on the ATP requirement for glycerolipid biosynthesis in adipose tissue of four mammalian species

1. Maximal glycerolipid biosynthesis activity was determined with 700 g homogenates of human, ovine, rat and bovine adipose tissue, and in the presence of varied concentrations of ATP and fluoride (as KF). 2. Minimal responses to either ATP or KF were observed with human homogenates. 3. Increasing ATP, from 4 to 20 mM, markedly increased glycerolipid biosynthesis in ovine and rat homogenates, but not in those of the bovine; similar responses were observed with 4 mM ATP plus 12.5 mM KF for rat and ovine. 4. Results indicated that KF inhibited ATP degradation in adipose tissue homogenates and that the severity of ATP degradation differed with species.

The use of general anaesthesia for tooth extraction in children in London: a multi-centre study

Following publication of the Poswillo report, the continued use of general anaesthesia in dentistry became the subject of a major debate. In particular, the provision of general anaesthetic services by general dental practitioners in order to carry out simple extractions for child patients has been called into question. Other authors have strongly supported the continued need for general anaesthesia and insist that for some patients it remains the technique of choice. There is, however, little evidence of current patterns of attendance from which argument may be advanced to support or refute the differing views. In this study data was drawn from three London dental teaching hospitals providing out-patient general anaesthesia for extractions. During the 12-month period investigated 7852 general anaesthetics had been administered for child patients. There was evidence of an increase in numbers at one centre when results were compared to those of a previous study and some evidence of a change in pattern of referral with time at the same centre, with an increase in the numbers of patients referred by general dental practitioners. Eighty-three per cent of the anaesthetics had been given for the extraction of carious primary teeth, with an average of 3.3 being extracted per child. Nearly one-third of the anaesthetics were for children under the age of 5 years.

Comparison of glycerolipid biosynthesis in homogenates from human, ovine, bovine and rat adipose tissue in vitro

1. Assay conditions were compared for glycerolipid biosynthesis in homogenates prepared from human abdominal, ovine and bovine subcutaneous, and rat epididymal adipose tissues. 2. In contrast to other species, longer incubation time and greater homogenate concentration resulted in decreased glycerolipid biosynthesis with rat adipose tissue homogenates. 3. Species differences were observed in concentration-dependency for ATP and fatty acids (palmitate, oleate and palmitoleate). 4. Results indicated that glycerolipid biosynthesis transpired at different rates in the four species, and that ovine and human adipose tissue homogenates had similar properties.

Glycerolipid biosynthesis in adipose tissue of the bovine during growth

1. Rates of palmitate esterification in tissue slices and glycerophosphate acyltransferase activity in homogenates were determined in bovine subcutaneous and intermuscular adipose tissue at 340, 418 or 498 kg of live weight. 2. Lower rib section fat accretion rates were observed from 340 to 418 kg than from 418 to 498 kg. 3. Changes in palmitate esterification rates at different body weights were consistent with reduced rib section fat accretion as well as with reported differences in fat accretion in subcutaneous and intermuscular fat depots. 4. Glycerophosphate acyltransferase activity was increased at 418 kg and remained elevated whereas palmitate esterification was decreased at 418 and then increased at 498 kg. 5. Differences between palmitate esterification and glycerophosphate acyltransferase in vitro may have been related to differences in substrate supply.

Effect of adipose tissue site, animal size, and fasting on lipolysis in bovine adipose tissue in vitro

1. Lipolytic rates expressed as mumol glycerol released per mg protein increased with body weight in Holstein steers. 2. Lipolytic rates were greatest in both inner and outer back fat and lowest in omental, perirenal, and intermuscular fat depots. 3. Epinephrine stimulated overall glycerol release 3-5-fold. 4. Fasting resulted in greater basal lipolytic rates but epinephrine-stimulated rates tended to be greater for nonfasted steer adipose tissue. 5. Lipolytic activity in adipose tissue seems to increase with growth and fattening, and differences in lipolytic rates between various depots diminish with growth.

Dental treatment for children under general anaesthesia in day care facilities at a London dental hospital

Day-stay facilities are gaining in popularity in general surgery, especially in surgery for children. In dentistry, day-stay care has been shown to be of great value for the treatment of specific groups of child patients, including handicapped and those too young to tolerate treatment with local anaesthetic alone. The present study considered the characteristics of 103 patients attending for treatment in the day-care facilities of the Eastman Dental Hospital, the morbidity of the technique and the acceptability of the service to those using it. Of the 103 patients, 46 were seen in the unit because they required minor oral surgery and 22 because of particular problems with management. Ninety-four patients had one or more symptoms following treatment. In at least 53 cases this related to the treatment and not to the anaesthetic. Despite a cost to the families in terms of money and time, the service proved acceptable to almost all of those who used it.

Growth, carcass characteristics, and lipid composition of adipose tissue and muscle of pigs fed canola

Sixty-one finishing pigs (53.4 kg) were fed a control diet (containing soybean meal) or diets containing 20% intact canola (IC) or 20% ground canola (GC) for 8 wk. Diets were not isocaloric. Daily gain and feed efficiency were not affected by dietary treatment, but pigs fed GC ate less than pigs fed either IC or the control diet. Carcass measurements, obtained on 43 of the pigs, were not affected by diet. For 27 pigs, fatty acid composition of perirenal adipose tissue (PRF), subcutaneous adipose tissue (SCF), and longissimus muscle (LDM) was analyzed. Nine pigs (three per treatment) were randomly selected for fatty acid composition analysis of intramuscular adipose tissue (IMF) and for cholesterol analysis of several tissues. Pigs fed canola had greater (P less than .05) proportions of mono- and polyunsaturated fatty acids and less (P less than .05) saturated fatty acids in PRF and SCF. The differences were more pronounced for PRF than for SCF. In the LDM, pigs fed canola tended to have elevated levels of unsaturated fatty acids at the expense of the saturated fatty acids, but this effect was significant for linolenic acid only. The fatty acid composition of IMF was not affected by diet (P greater than .05). Diet did not alter the cholesterol content of the tissues, but cholesterol in IMF was higher (P less than .05) than in PRF, SCF, and LDM. In conclusion, 20% IC or GC did not alter growth performance or carcass characteristics of pigs. Feeding of canola increased the degree of unsaturation of PRF and SCF, but it had less effect on IMF and LDM.

Effect of indomethacin, epinephrine, prostaglandin E2 and insulin on lipolysis in bovine adipose tissue in vitro

1. Fasting of ad libitum- or maintenance-fed steers for 4 to 9 days did not alter basal lipolytic rates in vitro. 2. Epinephrine stimulation of adipose tissue of fasted steers resulted in greater (P less than 0.05) lipolysis than in tissue from fed steers. 3. Prostaglandin E2 (PGE2) did not alter epinephrine-stimulated lipolysis in ad libitum- or maintenance-fed cattle. 4. Indomethacin did not influence basal lipolysis, even in the presence of PGE2. 5. Insulin neither affected basal lipolysis nor inhibited dibutyl cAMP-stimulated lipolysis.

An evaluation of bitewing radiographs in 5-year-old children

Bitewing radiographs remain the most universally accepted aid in the detection of approximal caries in posterior teeth. The aim of this study was to evaluate their use in 5-year-old children. A total of 435 selected sets of films were read and the numbers of readable and unreadable surfaces were recorded. Of the total, 57 per cent of the sets of films were wholly readable; out of a maximum of 8700, 7490 readable surfaces were seen. Of the 248 wholly readable sets of films, 172 (69 per cent) had no evidence of caries, fillings or extracted teeth. The most common reason for loss of information was that surfaces were absent from the film (accounting for 7 per cent of all surfaces). Blurring of the surface affected 4 per cent of surfaces and overlaps a further 3 per cent. Despite the deficiencies seen, caries was diagnosed from more than one-third of all sets of films.

Lipoprotein lipase gene expression in rat adipocytes is regulated by isoproterenol and insulin through different mechanisms

Lipoprotein lipase (LPL) is highly regulated by catecholamines and insulin in adipocytes. Isoproterenol, a beta-adrenergic agonist, decreases LPL enzyme activity, whereas insulin increases LPL activity. We have isolated an 868-basepair rat LPL cDNA clone to assess hormone-mediated changes in LPL steady state mRNA levels and LPL gene transcription rates in adipocytes. Northern blot analysis of isoproterenol-treated (10(-6) M) adipocytes showed that LPL steady state mRNA decreased by 15 min. Nuclear run-on transcription assays in isoproterenol-treated cells indicated that LPL gene transcription was also decreased at 15 min compared to that in control cells. Conversely, insulin (6.7 x 10(-8) M) mediated an increase in LPL steady state mRNA in treated adipocytes, yet LPL gene transcription was not different from that in control cells. Thus, the isoproterenol-mediated decrease in LPL enzyme activity and steady state mRNA levels in adipocytes is associated with decreases in LPL gene transcription. Insulin, which does not affect LPL gene transcription, increases LPL enzyme activity and steady state mRNA levels. The effect of insulin on LPL mRNA is probably due to insulin-induced changes in mRNA stability.

Glycerolipid biosynthesis in porcine adipose tissue in vitro: effect of adiposity and depot site

To compare genetic differences in glycerolipid biosynthesis, rates were determined in s.c. adipose tissue of lean and obese pigs at 28, 60 and 110 d of age. To compare depot-specific differences, glycerolipid biosynthetic rates were determined in outer s.c., middle s.c., perirenal and omental adipose tissues obtained from 105-kg contemporary pigs. Rates were determined with a 700 x g infranatant fraction of an adipose tissue homogenate by measuring glycerophosphate incorporation into total lipids (mostly phosphatidic acid) during 4 min. This assay represents entrance of substrates into the glycerolipid synthesis pathway or glycerophosphate acyltransferase (GPAT) activity. Rates measured for 60 min represent maximal synthesis of glycerolipid (more triacylglycerol than phosphatidic acid) or lipid synthesis capacity (LSC). Adipocyte diameter and volume were greater for adipose tissue of obese than of lean pigs both at 60 and 110 d. When expressed per cell, activity of GPAT and LSC were similar for lean and obese pigs at 28 d. At 60 d and 110 d, LSC was greater for obese than for lean pigs; GPAT activity was greater at 60 but not at 110 d in obese than in lean pigs. Expressed on a cell basis, GPAT activity was highest in omental and outer s.c., intermediate in perirenal and lowest in middle s.c. adipose tissue depots. Lipid synthesis capacity was highest in perirenal and lowest in outer and middle s.c. depots. Our results indicate that the LSC assay was more closely related to the accretion of fat in vivo than to GPAT activity.

Glycerolipid biosynthesis in porcine adipose tissue in vitro. II. Synthesis by various types of cellular preparations

Glycerolipid biosynthesis by porcine adipose tissue homogenates did not yield the 90+% triacylglycerol observed in situ. Consequently, we compared intact tissue slices and various subcellular fractions to characterize the usefulness of such systems to assess glycerolipid biosynthesis in vitro. Glycerolipid biosynthesis by porcine adipose tissue homogenates was measured in vitro using either [14C]-fatty acid or [14C]-glycerol-3-phosphate (G3P) as a radiolabelled substrate. Removal of residual 14C-labelled fatty acid from lipid extracts was difficult. Because G3P is soluble in water, residual [14C]-G3P separated easily from the glycerolipid-containing organic phase and, thus, was the preferred radiolabelled substrate. With tissue slices, glycerol and G3P were minimally incorporated into lipid so that [14C]-fatty acid was the preferred radiolabelled tracer. A washing procedure followed by thin layer chromatography was devised to separate residual [14C]-fatty acid from glycerolipids, including phospholipids. Fatty acid esterification into glycerolipids in tissue slices yielded about 4% phospholipids, whereas with homogenates, esterification yielded up to 50% phospholipids. Comparison of several subcellular fractions indicated that microsomes contained most of the glycerolipid biosynthetic activity when activity was expressed on a protein basis. However, when activities were expressed on a tissue wet weight basis, the 700 x g infranate and the 10,000 x g supernate had about equal activity that was far greater than the microsomes. The 700 x g infranate was the preferred enzyme preparation for assay of the entrance of G3P into the pathway as well as the capacity to synthesize triacylglycerol. Several methods of freezing and storing tissue or 700 x g infranates were not acceptable. Freezing of the 700 x g infranate in liquid N2 with storage at -80 degrees C may be an acceptable procedure.