Cogrinding as a Tool to Produce Sustained Release Behavior for Theophylline Particles Containing Magnesium Stearate

The aim of the present study was to explore the cogrinding technique as a tool to slow down the drug release from capsule formulations. To this end, the physical mixtures of theophylline–magnesium stearate were prepared and subjected to different milling times (1, 15, 30, 120 min). In order to investigate the effect of magnesium stearate concentration on drug release, various concentrations of magnesium stearate (1%, 3%, 5%, and 10%, w/w) were used. The dissolution rate of the drug from coground samples and physical mixtures were determined at pH 6.5 according to USP. The results showed that all coground formulations showed slower release rates than their physical mixture counterparts. The effect of cogrinding time on the drug release was complex. Cogrinding time had no significant effect on drug release when the amount of magnesium stearate was 1% (w/w). When the amount of magnesium stearate was increased from 1% to 3% and cogrinding time increased from 1 to 5 min, there was a significant reduction in drug release. Beyond 5-min cogrinding, the drug release increased again. For coground samples containing 5% or 10% (w/w) magnesium stearate, generally, the highest drug release was obtained at higher cogrinding time. This was due to a significant increase in surface area of particles available for dissolution as proven by scanning electron microscopy results. Fourier transform infrared and differential scanning calorimetry results ruled out any significant interaction between theophylline and magnesium stearate in solid state.     

Fuel Pellets from Wheat Straw: The Effect of Lignin Glass Transition and Surface Waxes on Pelletizing Properties

The utilization of wheat straw as a renewable energy resource is limited due to its low bulk density. Pelletizing wheat straw into fuel pellets of high density increases its handling properties but is more challenging compared to pelletizing woody biomass. Straw has a lower lignin content and a high concentration of hydrophobic waxes on its outer surface that may limit the pellet strength. The present work studies the impact of the lignin glass transition on the pelletizing properties of wheat straw. Furthermore, the effect of surface waxes on the pelletizing process and pellet strength are investigated by comparing wheat straw before and after organic solvent extraction. The lignin glass transition temperature for wheat straw and extracted wheat straw is determined by dynamic mechanical thermal analysis. At a moisture content of 8%, transitions are identified at 53°C and 63°C, respectively. Pellets are pressed from wheat straw and straw where the waxes have been extracted from. Two pelletizing temperatures were chosen??one below and one above the glass transition temperature of lignin. The pellets compression strength, density, and fracture surface were compared to each other. Pellets pressed at 30°C have a lower density and compression strength and a tendency to expand in length after the pelletizing process compared to pellets pressed at 100°C. At low temperatures, surface extractives have a lubricating effect and reduce the friction in the press channel of a pellet mill while no such effect is observed at elevated temperatures. Fuel pellets made from extracted wheat straw have a slightly higher compression strength which might be explained by a better interparticle adhesion in the absence of hydrophobic surface waxes.     

Superovulation and recovery of zygotes suitable for microinjection in different breeds of sheep

This study investigated the appropriateness of different superovulatory protocols in various breeds of sheep for obtaining a maximum of zygotes suitable for microinjection. Animals were mated either once or two to three times to fertile rams. In Experiment 1, a 24 h interval between a two to three times mating and egg recovery resulted in 42.2% suitable zygotes whereas with single mating only 10.4% fertilized eggs were obtained. The extension of the interval to 40 h associated with a two to three times mating resulted in a recovery of 42.9% fertilized eggs but most (70%) of these were already at the two-cell stage. In Experiment 2, eCG resulted in similar superovulatory responses in Merino ewes as the more labour requiring FSH treatment (8.1 ± 4.5 versus 7.5 ± 4.1 corpora lutea (CL); 6.3 ± 3.0 versus 6.8 ± 4.0 oocytes/ zygotes; 39.4% versus 40.6% fertilization rate). In Experiment 3, following superovulation with pFSH (Folltropin®) the number of CL was not different among Merino, Finn, Crossbreds (Blackface X Finn) and Texel sheep (8.6 ± 5.2; 10.3 ± 4.5; 8.5 ± 3.8; 8.2 ± 2.8, respectively) as was the number of recovered oocytes/ zygotes (7.4 ± 5.6; 9.8 ± 4.3; 7.3 ± 3.8; 6.4 ± 2.9, respectively). However, the number of unfertilized ova was higher (P < 0.05) in Finn sheep as compared with Crossbreds and Texel sheep (5.0 ± 3.3 versus 2.2 ± 2.3 and 1.9 ± 2.6). Similarly, the fertilization rate was higher (P < 0.05) in Crossbreds and Texel sheep (64.4% and 65.5%) as compared with Finn and Merino sheep (38.3% and 42.5%). In Experiment 4, it was shown that in Merino sheep purified FSH supplemented with 68.6% LH resulted in lower (P < 0.05) superovulatory responses as compared with purified FSH supplemented with 133.1% LH or Folltropin (LH contamination 0.1%) (4.7 ± 3.3 versus 8.8 ± 3.8 and 8.6 ± 5.2 CL; 3.8 ± 2.5 versus 7.4 ± 3.6 and 7.4 ± 5.6 oocytes/zygotes, respectively). A three times repeated superovulatory treatment and oviductal flush per animal at monthly intervals did reduce (P < 0.05) the number of CL, but had no deleterious effect on zygote yields and the percentage of microinjectable zygotes. We conclude that (1) at least a two to three times mating is required to obtain acceptable fertilization rates; (2) the interval between mating and recovery should be 24–26 h in order to obtain zygotes; (3) eCG results in similar superovulatory responses as FSH; (4) Folltropin® is a suitable drug to induce superovulation in sheep; (5) the LH content of the FSH preparation plays a significant role in the superovulatory response of sheep; (6) superovulation and embryo recoveries can be repeated at least three times per animal without decrease in efficiency.     

Ibuprofen-Loaded Calcium Stearate Pellets: Drying-Induced Variations in Dosage Form Properties

Pellets intended for oral dosing are frequently produced via extrusion/spheronization followed by drying. Typically, the last active process step, i.e., drying, is assumed to have little effect on the final dosage form properties (e.g., dissolution characteristics). Thus, there exist only a few studies of this subject. In the present study, calcium stearate/ibuprofen pellets were used as model system to investigate the impact of the drying conditions. Lipophilic calcium stearate matrix pellets containing 20% ibuprofen were prepared via wet extrusion/spheronization. Subsequently, desiccation, fluid-bed drying, and lyophilization were applied for granulation liquid removal. The impact of these drying techniques on the final pellet properties was evaluated. The in vitro dissolution behavior was dramatically altered by the drying techniques that were considered. The investigated pellets showed drug release rates that varied as much as 100%. As no polymorphic transitions occurred during drying, we focused on two possible explanations: (a) a change in the drug distribution within the pellets and (b) a change in pellet micro-structure (porosity, pore size). The ibuprofen distribution proved to be homogeneous regardless of the drying conditions. Pellet porosity and pore sizes, however, were modified by the drying process. Our results clearly demonstrate that a single process step, such as drying, can play a crucial role in achieving desired pellet properties and release profiles.     

Sintering of wax for controlling release from pellets

The purpose of the present study was to investigate incorporation of hydrophobic (ie, waxy) material into pellets using a thermal sintering technique and to evaluate the pellets in vitro for controlled release. Pellets prepared by extrusion-spheronization technology were formulated with a water-soluble drug, microcrystalline cellulose, and carnauba wax. Powdered carnauba wax (4%–20%) prepared by grinding or by emulsification was studied with an attempt to retard the drug release. The inclusion of ground or emulsified carnauba wax did not sustain the release of theophylline for more than 3 hours. Matrix pellets of theophylline prepared with various concentrations of carnauba wax were sintered thermally at various times and temperatures. In vitro drug release profiles indicated an increase in drug release retardation with increasing carnauba wax concentration. Pellets prepared with ground wax showed a higher standard deviation than did those prepared with emulsified wax. There was incomplete release at the end of 12 hours for pellets prepared with 20% ground or emulsified wax. The sintering temperature and duration were optimized to allow for a sustained release lasting at least 12 hours. The optimized temperature and duration were found to be 100° and 140 seconds, respectively. The sintered pellets had a higher hydrophobicity than did the unsintered pellets. Scanning electron micrographs indicated that the carnauba wax moved internally, thereby increasing the surface area of wax within the pellets. Published: September 14, 2007     

Characteristics of a Hydrated, Alginate-Based Delivery System for Cultivation of the Button Mushroom

The production of the button mushroom Agaricus bisporus with mycelium-colonized alginate pellets as an inoculant of the growing medium was investigated. Pellets having an irregular surface and porous internal structure were prepared by complexing a mixture of 1% sodium alginate, 2 to 6% vermiculite, 2% hygramer, and various concentrations of Nutrisoy (soy protein) with calcium chloride. The porous structure allowed the pellets to be formed septically and then inoculated and colonized with the fungus following sterilization. By using an enzyme-linked immunosorbent assay (ELISA) to estimate fungal biomass, the matrix components of the pellet were found to be of no nutritive value to A. bisporus. Pellets amended with Nutrisoy at a concentration of 0.5 to 8% supported extensive mycelial growth, as determined by significantly increased ELISA values, with a concentration of 4% being optimal and higher concentrations proving inhibitory. The addition of hydrated, mycelium-invaded pellets to the compost or casing layer supported the thorough colonization of the growing substrate and culminated in the formation of mushrooms that showed normal development and typical morphology. Yields and sizes of mushrooms were comparable from composts seeded with either colonized pellets or cereal grain spawn. Similarly, amending the casing layer with pelletized-mycelium-colonized compost resulted in a 2- to 3-day-earlier and more-synchronous emergence of mushrooms than with untreated casing. This technology shows the greatest potential as a pathogen-free inoculant of the casing layer in the commercial cultivation of mushrooms.     

Suppression of the lordosis reflex in female rats by chronic central melatonin implants

Pellets with beeswax:melatonin concentrations of 1:0, 5:1, and 2:1 were implanted near the suprachiasmatic nucleus of ovariectomized female rats. In repeated standard measures of the lordosis reflex after estrogen replacement, females with pellets containing either melatonin concentration were consistently less sexually receptive than were females with pure beeswax implants. Suppression of behavioral receptivity by melatonin is consistent with other antireproductive effects of the hormone. Melatonergic action could account for certain pharmacological findings previously attributed to serotonergic action.     

Efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by Haemonchus and Trichostrongylus species in lambs at pasture

The efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by trichostrongyle nematodes in sheep was assessed throughout 6 months. Twenty Ile de France lambs were divided into two groups (control and treated groups), which were kept in separate pastures. Animals of the treated group were fed with D. flagrans twice a week (Tuesdays and Fridays). Pellets were prepared with the fungus mycelia in liquid culture medium and contained approximately 20% fungus. They were mixed with the animals' diet at a concentration of 1 g pellet per 10 kg live weight. Faecal egg counts (FEC), packed cell volume (PCV), total serum protein and the animals' body weight were determined fortnightly from 7 October 2005 to 24 March 2006. Comparison of such parameters between groups showed no significant differences (P > 0.05), except on 10 February 2006, when the control group presented a higher mean FEC than the treated group (P < 0.05). Feeding sheep with pellets containing D. flagrans had no benefit to the prophylaxis of nematode infections under the experimental conditions used in the present study.     

Reproductive response and LH secretion in ewes treated with melatonin implants and induced to ovulate with the ram effect

Two experiments were conducted to examine the effects of treating seasonally anoestrous ewes with melatonin before ram introduction on reproductive response, and on LH secretion in anoestrous ewes induced to ovulate by rams.In Experiment 1, a total of 667 ewes from three flocks involving Merino (Flock 1, N = 149), Merino entrefino (Flock 2, N = 325) and Rasa Aragonesa (Flock 3, N = 203) breeds were used. Within each flock, ewes isolated from rams since the previous lambing were assigned at random to receive melatonin implants of Regulin (75, 175 and 105 in Merino, Merino entrefino and Rasa Aragonesa flocks, respectively) or to serve as untreated controls (74 in Merino, 150 in Merino entrefino and 98 in Rasa Aragonesa flocks). Fertile rams were introduced into all flocks 5 weeks after implantation in March (Flocks 1 and 2) or April (Flock 3), and remained with the ewes for a 50 day mating period. Percentage of ewes with luteal activity at ram introduction did not differ between melatonin treated and control ewes in any flock. There were no significant differences in either the mean interval from ram introduction to lambing or the distribution of lambing. Implantation with melatonin resulted in an improvement of prolificacy in all three flocks, although this only reached statistical significance in the Merino flock (1.15 vs. 1.03 in treated and control ewes, respectively, P < 0.05). Fertility was increased significantly (P < 0.05) in the Merino entrefino flock (64.5% in treated vs. 51.3% in control ewes).In Experiment 2, two trials were undertaken utilizing a total of 63 ewes. Trial 1 involved 24 mature Manchega ewes and Trial 2 involved 39 Merino ewe lambs. Half of the animals in each trial received a Regulin implant on 28 February (Trial 1) or 12 March (Trial 2) and the remaining half acted as controls. Rams were introduced 5 weeks after implantation and remained with the ewes for a 25 day period. In both trials, anoestrous ewes at ram introduction were bled at 20 min intervals for 3 h before and 5 h after ram introduction and then at 3 h intervals over the next 24 h for assessment of plasma concentrations of LH. Secretion of LH before or following introduction of rams was not affected by melatonin. Both treated and control anoestrous ewes in each trial responded to introduction of rams with an increase in the frequency of the LH pulses (P < 0.05), but no significant changes were detected in pulse amplitude or mean levels of LH. A preovulatory surge of LH was detected between 8 and 26 h after ram introduction, but neither mean interval from ram introduction to the peak of LH surge, nor the magnitude of the LH peak, was influenced by melatonin treatment.Results from this study show that: (1) melatonin implants administered during early seasonal anoestrus have the potential to improve reproductive performance in Spanish breeds of sheep, but the response is conditioned by breed, management system and environmental factors; (2) melatonin did not modify the secretion of LH in anoestrous ewes induced to ovulate by the ram effect under our experimental conditions.     

Effect of adenosine triphosphate on Perca fluviatilis sperm tails isolated in buffered sucrose

1. Sperm tails were isolated from mechanically disrupted spermatozoa of Perca fluviatilis and suspended in buffered sucrose solution. When freshly prepared suspensions were treated with ATP and magnesium chloride and centrifugal pellets obtained these weighed up to about 40% heavier than controls. 2. The effect is closely linked to the enzymic splitting of ATP and under conditions where this was inhibited no increase in weight was observed. Pellets from suspensions aged overnight at 2 degrees and then treated with ATP and magnesium chloride were no heavier than the controls although the suspensions had undiminished enzymic activity. Sperm tails from Salmo trutta did not show the effect. 3. Analyses showed that the weight increases were the result of uptake of sucrose solution and that sucrose completely penetrated the pellet water. Polyethylene glycol (mol.wt. 4000) did not penetrate the water of the pellets completely and an amount approximately equal to 1.9 times the flagellar dry weight was inaccessible. 4. Electron-microscopic studies indicated that the effect is the result of tail disintegration.     

Packaging of live Legionella pneumophila into pellets expelled by Tetrahymena spp. does not require bacterial replication and depends on a Dot/Icm-mediated survival mechanism

The freshwater ciliate Tetrahymena sp. efficiently ingested, but poorly digested, virulent strains of the gram-negative intracellular pathogen Legionella pneumophila. Ciliates expelled live legionellae packaged in free spherical pellets. The ingested legionellae showed no ultrastructural indicators of cell division either within intracellular food vacuoles or in the expelled pellets, while the number of CFU consistently decreased as a function of time postinoculation, suggesting a lack of L. pneumophila replication inside Tetrahymena. Pulse-chase feeding experiments with fluorescent L. pneumophila and Escherichia coli indicated that actively feeding ciliates maintain a rapid and steady turnover of food vacuoles, so that the intravacuolar residence of the ingested bacteria was as short as 1 to 2 h. L. pneumophila mutants with a defective Dot/Icm virulence system were efficiently digested by Tetrahymena sp. In contrast to pellets of virulent L. pneumophila, the pellets produced by ciliates feeding on dot mutants contained very few bacterial cells but abundant membrane whorls. The whorls became labeled with a specific antibody against L. pneumophila OmpS, indicating that they were outer membrane remnants of digested legionellae. Ciliates that fed on genetically complemented dot mutants produced numerous pellets containing live legionellae, establishing the importance of the Dot/Icm system to resist digestion. We thus concluded that production of pellets containing live virulent L. pneumophila depends on bacterial survival (mediated by the Dot/Icm system) and occurs in the absence of bacterial replication. Pellets of virulent L. pneumophila may contribute to the transmission of Legionnaires' disease, an issue currently under investigation.     

Immune responses in Indonesian thin tail and Merino sheep during a primary infection with Fasciola gigantica: lack of a specific IgG2 antibody response is associated with increased resistance to infection in Indonesian sheep.

After a primary infection with Fasciola gigantica, the immune responses in a resistant (Indonesian thin tail) and a susceptible (Merino) breed of sheep were analysed. The number of adult flukes recovered from the livers of the Indonesian thin tail sheep were significantly lower than those found in the Merino animals. On days 8, 14 and 25 p.i., Indonesian thin tail sheep exhibited a significantly higher eosinophilia than Merino sheep, whereas neutrophilia was significantly elevated in the Indonesian thin tail sheep on days 36 and 48 p.i. Serum from both sheep breeds demonstrated IgM, IgG1 and IgE responses to F. gigantica. In contrast, the Indonesian thin tail sheep produced significantly lower levels of IgG2 antibodies relative to the high level detected in Merino sheep. The IgE response was biphasic in both sheep breeds with the first response detected by day 14 and the second response developing from days 30 to 60 p.i. Western blotting showed that a similar profile of adult fluke antigens was recognised by IgG1 and IgE antibodies in both the Indonesian thin tail and Merino sheep. The IgE response was directed to a major antigen at about 92 kDa. We postulate that IgG2 could act as a blocking antibody for protective effector responses against F. gigantica in sheep and that the Indonesian thin tail sheep, by downregulating IgG2 responses, have an enhanced capacity for killing F. gigantica in vivo.     

Fate of mimosine administered orally to sheep and its effectiveness as a defleecing agent.

Mimosine was administered orally to Merino sheep once daily for periods of 1-3 days, either as the isolated compound or in the foliage of Leucaena leucocephala. A single daily dose of mimosine of 450 or 600 mg/kg body weight was effective for defleecing sheep. A daily dose rate of 300 mg/kg was effective for defleecing sheep if given on two successive days. The effectiveness of a treatment for defleecing sheep was related to the concentration of mimosine in plasma following dosing; defleecing ensued when the concentration of mimosine in plasma was maintained above 0-1 mmol/l for at least 30 h. The main products excreted in urine were mimosine and 3,4-dihydroxypyridine (DHP); small amounts of mimosinamine were also excreted. During the first day following dosing, the major excretory product was mimosine; DHP was an important component during the second and third days. In the three days following the start of dosing, between 32 and 53% of the mimosine given was accounted for as mimosine in the urine. Following an intravenous infusion of mimosine, no DHP was detected in urine; most of the mimosine was excreted intact but a small amount (c. 9%) was excreted as mimosinamine.     

Extrusion/spheronization of pectin-based formulations. I. Screening of important factors

This study investigated the possibility of producing pectin-based pellets by extrusion/spheronization. The study also identified factors influencing the process and the characteristics of the resulting product. Three types of pectin with different degrees of amid and methoxyl substitution were studied in combination with different granulation liquids (water, calcium chloride, citric acid, and ethanol) and/or microcrystalline cellulose. Pellets were prepared in a power-consumption-controlled, twinscrew extruder; then they were spheronized and dried. The products were characterized by image analysis, sieving analysis, and disintegration and dissolution tests. The results were evaluated by multivariate analysis. Different additives, either in the granulation liquid or in the powder mixture, influenced the ability of the extruded mass to form pellets (the processability) with this technique. However, the various pectin types responded to modifications to a different extent. Short, nearly spherical pellets are obtained with granulation liquids, such as ethanol, that reduce the swelling ability of pectin. Pellets produced with ethanol are, however, mechanically weak and tend to ditintegrate. Pectin molecules with a high degree of free carboxylic acid groups seem to be more sensitive to changes in the granulation liquid. Addition of microcrystalline cellulose as an extrusion aid generally resulted in improvements in shape and size. It was demonstrated that the processability of pectin as well as the characteristics of the products can be influenced in different ways during the process (eg, adding substances to the granulation liquid or to the powder mixture).     

Earthworms in the diet of Herring Gulls Larus argentatus breeding on an off-shore island

ABSTRACT

Pellets of indigestible material regurgitated by Herring Gulls Larus argentatus breeding on Lady Isle, Firth of Clyde, Scotland, were collected in 2018 and 2019 and examined for earthworm chaetae. Nearly two-thirds (65.6%) of the 314 pellets came from gulls that had consumed one or more earthworms. Significantly fewer pellets (57.6%) contained chaetae in 2018, a relatively dry May to July, than in 2019 (72.0%) when rainfall was close to the long-term average for May to July. There were significant associations between the presence of large quantities of terrestrial vegetation in the pellet and the detection of large numbers of earthworm chaetae and/or fragments of terrestrial arthropods, suggesting that recent consumption of these food items is likely when pellets contain large quantities of vegetation.     

Effects of pelletized anticoagulant rodenticides on California quail

A moribund, emaciated California quail (Callipepla californica) that was found in an orchard in the state of Washington had an impacted crop and gizzard. Pellets containing the anticoagulant chlorophacinone (Rozol, RO) were in the crop; the gizzard contents consisted of a pink mass of paraffin that was selectively accumulated from the paraffinized pellets. The plasma prothrombin time of 28 sec was near that determined for control quail. The signs of RO intoxication seen in the moribund wild quail were duplicated in captive quail given ad libitum diets of either RO or another paraffinized chlorophacinone pellet (Mr. Rat Guard II, MRG). This left little doubt that paraffin impaction of the gizzard was the primary problem. All captive quail fed RO or MRG pellets showed no increases in prothrombin times compared to control values, died in an emaciated condition, and had gizzards impacted with paraffin.     

优良的BMPR-IB基因型可提高绵羊冷冻胚胎的受胎效果

以控制BooroolaMerino羊高繁殖力的BMPR-IB基因为候选基因,以小尾寒羊及其杂交羊、东北半细毛羊、澳洲美利奴羊、德国肉用美利奴羊、萨福克羊、特克塞尔羊、夏洛莱羊为试验对象,采用PCR-限制性片段长度多态性(PCR-RFLP)方法进行基因单核苷酸多态性(SNP)检测和基因型分析,同时研究基因对高繁殖力的影响.研究结果表明:小尾寒羊及其杂交羊、东北半细毛羊和夏洛莱羊群体中发现了与BooroolaMerino羊相同的A746G碱基突变,而小尾寒羊及其杂交羊群体的B等位基因频率明显高于其他2个品种.另外4个品种中未发现此突变.携带B等位基因的群体较非携带B等位基因群体排出更多的卵子,排卵后黄体直径较小.移植入冷冻胚胎后, 、B 和BB3种基因型群体的妊娠率分别为38.78%、45.71%和66.67%.由此推断,BMPR-IB基因突变很有可能从增加卵巢排卵数和提高胚胎着床及妊娠建立效率两个方面同时影响绵羊高繁殖力性状.所得BB型群体冻胚移植妊娠率明显高于 和B 型群体,已接近鲜胚移植水平,通过PCR-RFLP方法进行基因型分析,选用合适基因型群体作为胚胎移植受体,有可能为提高绵羊胚胎移植受胎率提供新的方向.     

Influence of Starting Material Particle Size on Pellet Surface Roughness

The purpose of this study was to investigate the effect of pelletization aids, i.e., microcrystalline cellulose (MCC) and cross-linked polyvinyl pyrrolidone (XPVP), and filler, i.e., lactose, particle size on the surface roughness of pellets. Pellets were prepared from powder blends containing pelletization aid/lactose in 1:3 ratio by extrusion–spheronization. Surface roughness of pellets was assessed quantitatively and qualitatively using optical interferometry and scanning electron microscopy, respectively. Both quantitative and qualitative surface studies showed that surface roughness of pellets depended on the particle size of XPVP and lactose used in the formulation. Increase in XPVP or lactose particle size resulted in rougher pellets. Formulations containing MCC produced pellets with smoother surfaces than those containing XPVP. Furthermore, surface roughness of the resultant pellets did not appear to depend on MCC particle size. Starting material particle size was found to be a critical factor for determining the surface roughness of pellets produced by extrusion–spheronization. Smaller particles can pack well with lower peaks and valleys, resulting in pellets with smoother surfaces. Similar surface roughness of pellets containing different MCC grades could be due to the deaggregation of MCC particles into smaller subunits with more or less similar sizes during wet processing. Hence, for starting materials that deaggregate during the wet processing, pellet surface roughness is influenced by the particle size of the material upon deaggregation.     

Studies of the congenitally goitrous sheep. Iodoproteins of the goitre

1. Congenitally goitrous thyroid tissue was obtained from South Australian Merino sheep. Ultrastructural studies of the secretory cells in this tissue showed active cells of normal appearance, containing apical protein droplets. 2. (125)I-labelling in vivo of goitre tissue was used to investigate the iodoproteins, in which the major proportion of (125)I appeared in the cell protein fraction soluble in 0.9% sodium chloride (average 62% in goitres from untreated sheep). 3. Ammonium sulphate fractionation showed two clear peaks of iodoprotein precipitation, one at 35-40% saturation and the other at 50-55% saturation. Both iodoprotein fractions contained iodotyrosines and iodothyronines, which were identified chromatographically after enzymic hydrolysis of the protein. 4. Polyacrylamide-gel electrophoresis at pH9.4, at either 7.5 or 5.0% acrylamide concentration, was used to characterize the iodoproteins. Two major fractions were observed, the fastest-migrating fraction coincident with serum albumin, and a slower-migrating, less-well-defined zone. This fraction migrated in 7.5% acrylamide gel, which excluded normal thyroglobulin. 5. Density-gradient (10-40% sucrose) centrifugation was used to determine the approximate sedimentation coefficients of the iodoproteins, which showed major components at s(20,w) 8-9S and s(20,w)<5S. 6. Immunoprecipitation with rabbit anti-(sheep thyroglobulin) failed to sediment (125)I-labelled proteins from goitre extracts. 7. Ouchterlony-type double diffusion in agar plates demonstrated immunoprecipitation lines between rabbit anti-(sheep thyroglobulin) and both the concentrated goitre extract and its Sephadex G-200-excluded fraction, which were confluent with that obtained on reaction with purified normal thyroglobulin. 8. It was concluded that both major iodoprotein fractions were capable of supplying thyroid hormones to the animal, and that the fraction of s(20,w)<5S was iodinated serum albumin. As (125)I-labelled thyroglobulin was not detected in goitre tissue from untreated or thyroxine-treated animals, it was possible that the genetic defect causing goitre resulted in an abnormal thyroglobulin, incapable of being iodinated but immunologically reactive.     

Brachygnathia,cardiomegaly and renal hypoplasia syndrome (BCRHS) in Merino sheep maps to a 1.1‐megabase region on ovine chromosome OAR2

A genome scan was conducted to map the autosomal recessive lethal disorder brachygnathia, cardiomegaly and renal hypoplasia syndrome (BCRHS) in Poll Merino sheep. The scan involved 10 affected and 27 unaffected animals from a single Poll Merino/Merino sheep flock, which were genotyped with the Illumina Ovine SNP50 BeadChip. Association and homozygosity mapping analyses located the disorder in a region comprising 20 consecutive SNPs spanning 1.1 Mb towards the distal end of chromosome OAR2. All affected animals and none of the unaffected animals were homozygous for the associated haplotype in this region. These results provide the basis for identifying the causative mutation(s) and should enable the development of a DNA test to identify carriers in the Poll Merino sheep population. Understanding the molecular control of BCRHS may provide insight into the fundamental genetic control and regulation of the affected organ systems.