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PubMed1986

Effect of relative shell size in turtles on water and electrolyte composition.

Interspecific differences in water, sodium, and potassium concentrations of entire freshwater turtles are related to the relative size of the shell. Species with proportionately smaller shells have higher water and potassium concentrations but lower sodium concentrations (expressed as mumol/g wet mass). These effects are associated with variation in the amount of shell bone, which is lower in water and potassium concentrations than other tissues. Within a single species there are also differences in composition related to total wet mass and relative shell mass. Smaller turtles have a relatively larger overall water concentration, a lower overall sodium concentration (expressed as mumol/g wet mass), and a larger relative wet mass of shell (expressed as % total wet mass). The shell in small turtles is lower in relative dry mass, higher in water concentration, and lower in sodium concentration (expressed as mumol/g wet mass) than in large turtles. There is also a striking inverse size-related difference in the proportion of overall sodium that is exchangeable. This is due to a decrease in the proportion of exchangeable sodium in the shell of larger turtles, perhaps related to progressive calcification. The magnitude of the effects of size and/or age on water and electrolyte composition of turtles has not been previously recognized but must now be taken into account before any interspecific or intraspecific comparisons in body composition are made.

Animals↗

PubMed1992

Regulation of calbindin mRNA and calbindin turnover in intestine and shell gland of the chicken.

A synthetic oligonucleotide was used as a probe for measurement of calbindin mRNA in the shell gland and intestine of chickens. The half time of calbindin mRNA in the duodenum and shell gland was estimated at 2 and 3.6 h and that of calbindin at 13.9 and 32.6 h, respectively. The formation rates of calbindin mRNA were 0.37 and 0.17 pmol.h-1.g-1 and the rate of calbindin formation was 0.099 and 0.031 microgram.pmol mRNA-1.h-1 in the duodenum and shell gland, respectively. In the shell gland, calbindin mRNA and calbindin appeared at the time of sexual maturation during calcification of the first egg shell. Calbindin mRNA fluctuated markedly during the daily egg cycle, in close temporal association with egg shell calcification. When Ca2+ deposition was eliminated by expulsion of the ovum, the rise in calbindin mRNA was prevented. An indirect suppression of Ca2+ deposition by administration of the carbonic anhydrase inhibitor acetazolamide also resulted in a decrease in calbindin mRNA. The results are consistent with a possible role of Ca2+ flux in the regulation of calbindin mRNA appearance in the shell gland of chickens.

Animals↗

PubMed2005

Opisthobranchia (Mollusca, Gastropoda) - more than just slimy slugs. Shell reduction and its implications on defence and foraging.

BACKGROUND: In general shell-less slugs are considered to be slimy animals with a rather dull appearance and a pest to garden plants. But marine slugs usually are beautifully coloured animals belonging to the less-known Opisthobranchia. They are characterized by a large array of interesting biological phenomena, usually related to foraging and/or defence. In this paper our knowledge of shell reduction, correlated with the evolution of different defensive and foraging strategies is reviewed, and new results on histology of different glandular systems are included. RESULTS: Based on a phylogeny obtained by morphological and histological data, the parallel reduction of the shell within the different groups is outlined. Major food sources are given and glandular structures are described as possible defensive structures in the external epithelia, and as internal glands. CONCLUSION: According to phylogenetic analyses, the reduction of the shell correlates with the evolution of defensive strategies. Many different kinds of defence structures, like cleptocnides, mantle dermal formations (MDFs), and acid glands, are only present in shell-less slugs. In several cases, it is not clear whether the defensive devices were a prerequisite for the reduction of the shell, or reduction occurred before. Reduction of the shell and acquisition of different defensive structures had an implication on exploration of new food sources and therefore likely enhanced adaptive radiation of several groups.

Journal Article↗

PubMed2000

The shell dissolution of various empty hard capsules.

The shell dissolution properties of gelatine, gelatine/polyethylene glycol (PEG) and hydroxypropyl methylcellulose (HPMC) capsules were studied as a function of temperature, dissolution medium, and after different storage conditions. In any dissolution medium with a pH below or equal to 5.8, HPMC capsule shells dissolved rapidly, and there was no difference in the time in which dissolution occurred in the tested temperature interval of 10 to 55 degrees C. Gelatine and gelatine/PEG capsule shells, generally, did not dissolve at temperatures below 30 degrees C. The shell dissolution time of all capsules tested was prolonged and more variable in mixed phosphate buffer pH = 6.8. The addition of enzymes (pepsin, pancreatin) to any dissolution medium was found not to enhance the differences between the different types of capsules investigated. In practical terms, the results indicated that capsule formulations should not be taken with drinks from the carbonated Cola-type. Gelatine containing capsules should preferably be administered with a warm drink, whereas HPMC capsules could be given with cold or warm drinks. The latter type of capsules should also be preferred for preparations to be taken in the fasted state. A short storage of gelatine containing capsules under hot humid tropical conditions appeared not to alter the dissolution properties of the shells, and changes in disintegration times and dissolution times of formulations filled in such capsules might be a reflection of changes of the powders incorporated rather than of the capsule shells. However, a short storage of HPMC capsules under such conditions appeared to influence the capsule shell matrix.

Administration, Oral↗

PubMed2005

Hedonic hot spot in nucleus accumbens shell: where do mu-opioids cause increased hedonic impact of sweetness?

Mu-opioid systems in the medial shell of the nucleus accumbens contribute to hedonic impact ("liking") for sweetness, food, and drug rewards. But does the entire medial shell generate reward hedonic impact? Or is there a specific localized site for opioid enhancement of hedonic "liking" in the medial shell? And how does enhanced taste hedonic impact relate to opioid-stimulated increases in food intake? Here, we used a functional mapping procedure based on microinjection Fos plumes to localize opioid substrates in the medial shell of the nucleus accumbens that cause enhanced "liking" reactions to sweet pleasure and that stimulate food intake. We mapped changes in affective orofacial reactions of "liking"/"disliking" elicited by sucrose or quinine tastes after D-Ala2-N-Me-Phe4-Glycol5-enkephalin (DAMGO) microinjections in rats and compared hedonic increases to food intake stimulated at the same sites. Our maps indicate that opioid-induced increases in sucrose hedonic impact are generated by a localized cubic millimeter site in a rostrodorsal region of the medial shell. In contrast, all regions of the medial shell generated DAMGO-induced robust increases in eating behavior and food intake. Thus, our results identify a locus for opioid amplification of hedonic impact and reveal a distinction between opioid mechanisms of food intake and hedonic impact. Opioid circuits for stimulating food intake are widely distributed, whereas hedonic "liking" circuits are more tightly localized in the rostromedial shell of the nucleus accumbens.

Animals↗

PubMed2003

The effect of digenea larvae on calcium content in the shells of Lymnaea stagnalis (L.) individuals.

The objective of this work was to examine the calcium concentration in the shells of naturally infected individuals of Lymnaea stagnalis. Calcium concentration in the water of lakes and in snail shells was examined by the EDTA method. Calcium concentration in the shells of infected snails was found to be higher than that in the shells of uninfected ones only in the lake with the lowest calcium concentration in water. However, this difference is not evidence of hypercalcification of snail shells caused by trematode larvae but suggests that the limited calcium concentration in the environment can be a very good factor for studying snail shell calcification under natural conditions. Moreover, small adult snails from 2 lakes had more calcium in their shells than did large ones. Different reproductive rates of different-sized snails could be the cause of this phenomenon.

Analysis of Variance↗

PubMed2005

Differences in shell shape of naturally infected Lymnaea stagnalis (L.) individuals as the effect of the activity of digenetic trematode larvae.

The shells of Lymnaea stagnalis show great morphological variability. This phenomenon has been described as the result of an environmental influence. The main object of the present study was to compare some biometric data from shells of naturally infected and uninfected snails from 25 different lakes in the central part of Poland. The height of the shell, the height of the spiral, and the width of the shell were measured. Some inter- and intrapopulation differences among individuals were found. Greater variability of shell shape was observed among snails parasitized with digenean larvae than in nonparasitized ones. Snails infected with Echinoparyphium aconiatum, Echinostoma revolutum, Diplostomum pseudospathaceum, and Opisthioglyphe ranae differed in shell shape compared with uninfected individuals. Snails infected with Plagiorchis elegans did not differ from uninfected individuals. The same was true of snails in which the commensal oligochaete, Chaetogaster limnei, was found. The results of the present study support the assumption that the deformation of shells of the snails under study was in some way influenced by the presence of certain species of digenetic trematodes.

Animals↗

PubMed2004

A constrained liner cemented into a secure cementless acetabular shell.

BACKGROUND: Constrained acetabular components have been used to treat hips with recurrent instability following total hip arthroplasty and hips that demonstrate instability during revision surgery. In such hips, when a secure cementless acetabular shell is present, the surgeon can cement a constrained liner into the existing shell. The purpose of this study was to evaluate the clinical and radiographic outcome of this technique with use of a tripolar constrained liner that was cemented into a well-fixed cementless acetabular shell. METHODS: Between 1988 and 2000, constrained liners were cemented into thirty-one well-fixed cementless acetabular shells at three centers. The average age of the patients at the time of the index surgery was 72.1 years, and the indications for the procedure were recurrent hip instability in sixteen hips and intraoperative instability in fifteen hips. The patients were evaluated with respect to the clinical outcome and radiographic evidence of shell loosening and osteolysis. RESULTS: At an average duration of follow-up of 3.9 years, twenty-nine liners (94%) were securely fixed in the cementless shells and two constrained liners had failed. One liner failed because it separated from the cement, and one failed because of fracture of the capturing mechanism. Both hips were successfully revised with another cemented tripolar constrained liner. No acetabular component demonstrated radiographic evidence of progressive loosening or osteolysis. CONCLUSIONS: A constrained tripolar liner cemented into a secure, well-positioned cementless acetabular shell provides stability and durability at short-term follow-up. Careful attention to the preparation of the liner, the sizing of the component, and the cementing technique are likely to reduce the failure of this construct, which can be used for difficult cases of total hip instability.

Acetabulum↗

PubMed2005

Total hip replacement with the CLS expansion shell and a structural femoral head autograft for patients with congenital hip disease.

BACKGROUND: Reconstruction of a dysplastic acetabulum in a patient with osteoarthritis of the hip may be accomplished with a variety of surgical techniques. The aim of our study was to assess the outcomes of total hip replacement with the uncemented CLS expansion shell and a structural femoral head autograft to augment the deficient acetabulum in patients with osteoarthritis secondary to congenital hip disease. METHODS: Between 1990 and 1994, we used a CLS expansion shell with a structural femoral head autograft in forty-three consecutive patients (forty-three hips) with osteoarthritis secondary to congenital hip disease. The ratio of male to female patients was 5:38, and the mean age of the patients was forty-eight years. According to the preoperative radiographic assessment, the dysplasia was categorized as Crowe type I in six patients, Crowe type II in thirty-one patients, and Crowe type III and type IV in three patients each. No patient was lost to follow-up. The mean duration of follow-up was 120 months. Plain radiographs were made immediately after surgery and at the latest follow-up evaluation. Clinical outcomes were determined with use of the Harris hip score and the Merle d'Aubigné and Postel score, and a radiographic analysis was performed. RESULTS: Postoperatively, the mean Harris hip score had improved 58 points for patients with Crowe type-I and II dysplasia, 47 points for patients with Crowe type-III dysplasia, and 46 points for patients with Crowe type-IV dysplasia (p < 0.05 for all). At the latest follow-up examination, the mean Harris hip score for all patients was 92.6 points. The mean Merle d'Aubigne and Postel score was 8.3 points preoperatively and 15.8 points at the time of the latest follow-up. The mean coverage of the shell by the graft immediately after surgery was 32.2%. Osteointegration of the CLS expansion shell was evident radiographically in all forty-three hips at the latest follow-up evaluation. There were no failures of the bone grafts. Clinical survival of the CLS expansion shell with a structural femoral head autograft was 100% at a mean of ten years after surgery. The rate of survival of the shell, with radiographic signs of loosening as the end point, was 88.2% at ten years. CONCLUSIONS: The CLS uncemented expansion shell, when used with a structural femoral head autograft, provides a reliable reconstruction, augments deficient acetabular bone stock, and allows placement of the socket at or close to the anatomic center of hip rotation in patients undergoing total hip arthroplasty to treat the sequelae of congenital hip disease.

Acetabulum↗

PubMed2001

Heated scallop-shell powder slurry treatment of shredded cabbage.

The main component of scallop-shell powder is calcium carbonate (CaCO3). Through heat treatment, CaCO3 in the shell is converted to CaO, which exhibits antibacterial activity. The disinfecting effect of heated scallop-shell powder on shredded cabbage was investigated for various powder concentrations (0.1 to 1.0 g dm(-3)) and treatment temperatures (10 to 40 degrees C). Scallop-shell powder treatment was found to reduce the aerobic bacteria count in cabbage, with increasing effectiveness at higher powder concentrations and treatment temperatures. Coliforms were completely eliminated within 5 min with as little as 0.1 g dm(-3) powder treatment. During storage at 4 degrees C, aerobic bacterial counts did not increase after powder treatment, whereas counts increased with water-washing or sodium hypochlorite treatment at 200 microg dm(-3). The inactivation pattern of bacterial cells in shredded cabbage involved an accelerated decline followed by an extended tail at powder concentrations of 0.1 and 0.5 g dm(-3). We postulate that a fraction of bacterial cells in the initial population becomes tolerant to the shell powder. A proposed model accurately predicts the reducing bacterial counts on shredded cabbage by scallop-shell powder treatment. The decrease in the L-ascorbic acid content of shredded cabbage was approximately 20 to 30% for scallop-shell powder treatment at 0.1 and 0.5 g dm(-3) (20 degrees C), which is almost identical to that by sodium hypochlorite treatment at 200 micorg dm(-3).

Bacteria, Aerobic↗

PubMed2002

Effects of 5-HT1B receptor ligands microinjected into the accumbal shell or core on the cocaine-induced locomotor hyperactivity in rats.

The present study was designed to examine the effect of 5-HT1B receptor ligands microinjected into the subregions of the nucleus accumbens (the shell and the core) on the locomotor hyperactivity induced by cocaine in rats. Male Wistar rats were implanted bilaterally with cannulae into the accumbens shell or core, and then were locally injected with GR 55562 (an antagonist of 5-HT1B receptors) or CP 93129 (an agonist of 5-HT1B receptors). Given alone to any accumbal subregion, GR 55562 (0.1-10 microg/side) or CP 93129 (0.1-10 microg/side) did not change basal locomotor activity. Systemic cocaine (10 mg/kg) significantly increased the locomotor activity of rats. GR 55562 (0.1-10 microg/side), administered intra-accumbens shell prior to cocaine, dose-dependently attenuated the psychostimulant-induced locomotor hyperactivity. Such attenuation was not found in animals which had been injected with GR 55562 into the accumbens core. When injected into the accumbens shell (but not the core) before cocaine, CP 93129 (0.1-10 microg/side) enhanced the locomotor response to cocaine; the maximum effect being observed after 10 microg/side of the agonist. The later enhancement was attenuated after intra-accumbens shell treatment with GR 55562 (1 microg/side). Our findings indicate that cocaine induced hyperlocomotion is modified by 5-HT1B receptor ligands microinjected into the accumbens shell, but not core, this modification consisting in inhibitory and facilitatory effects of the 5-HT1B receptor antagonist (GR 55562) and agonist (CP 93129), respectively. In other words, the present results suggest that the accumbal shell 5-HT1B receptors play a permissive role in the behavioural response to the psychostimulant.

Animals↗

PubMed1991

Embryonic development of the shell in biomphalaria glabrata (Say).

During embryogenesis of the fresh water snail Biomphalaria glabrata (Say) (Pulmonata, Basommatophora) shell formation has been studied by light and electron microscopical techniques. The shell field invagination (SFI), the secretion of the first shell layers, the development of the shell-forming mantle edge gland and spindle formation have been investigated. During embryonic development at 28 degrees C environmental temperature, the shell field invaginates after 35 h. After 40 h the SFI is closed apically by cellular protrusions and scale-like precursors of the periostracum. The first electron translucent layer of the periostracum stems from electron dense vesicles of the cells which lie at the opening of the SFI. A second electron dense layer appears some hours afterwards. When the shell appears birefringent in the polarizing microscope (45 h of development) calcium can be detected in it using energy dispersive x-ray analysis. As calcification occurs the intercrystalline matrix appears under the periostracum and the SFI begins to open. In embryos of 60 h the mantle cavity appears at the left caudal side. When the mantle edge groove develops (65 h of development) lamellate units are added to the outer layer of the periostracum, but no distinct lamellar layer is formed in B. glabrata. In addition to the lamellar cell and the periostracum cell, a secretory cell can be observed in the developing groove. After 65 h of development, spindle formation starts and the shell begins to coil in a left hand spiral. After 5 days of development the embryos are ready to leave the egg capsules.

Animals↗

PubMed1987

Calcium regulation in the embryonic chick. III. Calcium and phosphate in serum and allantoic fluid of normal and shell-less embryos.

Calcium metabolism of chicken embryos was profoundly affected by incubation in shell-less culture, but phosphate metabolism was largely undisturbed. Shell-less embryos exhibited hypocalcemia and hypocalciuria relative to normal embryos but had similar levels of phosphate in serum and allantoic fluid. The concentration of calcium in allantoic fluid declined during incubation in both groups, owing largely to accompanying increases in allantoic volume, but total amounts of calcium in the allantois did not vary with time. Both normal and shell-less embryos maintained higher concentrations of calcium in serum than in allantoic fluid, with shell-less embryos maintaining a larger gradient between serum and allantoic compartments. In contrast, serum and allantoic concentrations of inorganic phosphate increased over time in both normal and shell-less embryos, and both groups maintained generally higher concentrations of inorganic phosphate in the allantoic sac than in serum. Treatment of embryos with parathyroid hormone had no effect on calcium and phosphate metabolism. Embryos maintained in shell-less culture grew more slowly than those incubated normally and consequently had a dry mass about half that of normal embryos on day 18. Shell-less embryos also exhibited abnormalities in fluid balance, which were reflected in their inability to maintain normal allantoic volume and in their higher relative hydration compared to embryos incubated in ovo.

Allantois↗

PubMed1973

Ecological studies on the breeding of Aedes aegypti and other mosquitos in shells of the giant African snail Achatina fulica.

The breeding of larvae of Aedes aegypti, Aedes simpsoni, and Eretmapodites quinquevittatus in empty shells of Achatina fulica was studied in the coastal zone of Dar es Salaam, Tanzania. The average density of shells was estimated to be 228 per ha. From 11 to 35% were positive for mosquito larvae. A. aegypti were found in 82-84% of positive shells; A. simpsoni in 8-13%. On Msasani peninsula, during the 3-month rainy season April-June 1970, the larval density of A. aegypti in shells was estimated at 1 100 per ha, that of A. simpsoni and E. quinquevittatus being estimated at 60 and 280 larvae per ha, respectively.Empty shells of A. fulica may contain up to 250 ml of water (average: 56.5 ml). The number of larvae per shell varies from 1 to 35 (average: 8.4) and it was estimated that, depending on the availability of food, and other factors, approximately 10 ml of water are required per larva. Viable eggs of A. aegypti were still to be found in 4% of the shells at the end of the dry season.

Aedes↗

PubMed1995

Effects of dopamine depletion on the morphology of medium spiny neurons in the shell and core of the rat nucleus accumbens.

Nucleus accumbens receives a dense dopaminergic innervation which is important in regulating motivated states of behavior such as goal-directed actions, stimulus-reward associations and reinforcement of addictive substances. The shell and core territories of this nucleus each receive functionally and morphologically distinct dopaminergic inputs and lesions of the ascending pathways totally deprive the core but not the shell of dopaminergic fibers. Medium spiny neurons are the principal targets of dopaminergic terminals. The present study explored whether the loss of dopamine inputs can affect these neurons and whether cells in the shell and core would be equally susceptible to such a loss. Intracellular injection in fixed slices and neuronal reconstruction were used to analyze the dendritic trees of 62 neurons in the shell and core of animals that received a unilateral, chronic 6-hydroxydopamine lesion of the medial forebrain bundle. In the dopamine-depleted core, dendrites are significantly shorter (16% decrease) than in the intact core and in both the dopamine-depleted core and lateral shell, dendrites are less spiny than in respective control regions. Dopamine loss in the medial shell is associated with significantly more tortuous dendrites that are lower in spine density. However, the number of spines is not reduced which may mean that the increase recorded for segment length, although insignificant in tests, could be responsible for the change in spine density. These data suggest that the loss of dopamine can affect accumbal neuronal morphology and, moreover, can affect neuronal structures differentially in the shell and core.

Animals↗

PubMedDate not supplied

Determination of shell content in palm kernel cake.

A method for determining shell in palm kernel cake (PKC) is described. This simple and rapid method requires little pretreatment compared with the method currently used in PKC trade, in which the sample undergoes defatting, acid and alkali digestion, and washing, before a chloroform-alcohol solution is used to separate the shells. In the proposed method, only defatting the sample is required. The shells are separated by the density difference between the shell and PKC in a potassium iodide solution. Recoveries of at least 93% were obtained, and the correlation coefficient between the actual shell content and the determined shell content was 0.999, with gradients of 0.97 and 0.98 for fine and coarse shell, respectively.

Animal Feed↗

PubMed2026

TNF-NF-κB signaling mediates immune-biomineralization crosstalk during shell repair under ocean acidification in Mytilus edulis.

Ocean acidification (OA) impairs biomineralization in bivalves, but its effects on immune-biomineralization crosstalk during shell repair remain unknown. Here, we exposed adult Mytilus edulis bearing standardized shell perforations to three pH levels (8.1, 7.9, and 7.7) for up to 40 days. OA slowed early repair and caused microstructural disorganization and an approximately 87% reduction of compressive strength at pH 7.7, yet the damaged area appeared largely closed by day 15, suggesting a decoupling between morphological closure and functional recovery. In addition, transcriptomic profiling of hemocytes and mantle tissue, based on an average of 6.5 Gb of clean reads per sample mapped to the M. edulis reference genome (NCBI Assembly GCF_000511035.1), revealed that these shell-level defects were accompanied by coordinated immune and metabolic reprogramming. Hemocytes, the primary immune effector cells of bivalves, exhibited pH- and time-dependent shifts with moderate acidification (pH 7.9) promoting inflammatory transcripts, whereas severe acidification (pH 7.7) suppressed these signals while upregulating stress-associated pathways; both treatments consistently downregulated lysosomal proteases and NF-κB negative regulators. The mantle, a primarily mineralizing organ, paradoxically upregulated immune-related genes while suppressing oxidative phosphorylation and extracellular matrix pathways. This tissue-level imbalance, with hemocytes recruited but functionally constrained and mantle metabolically suppressed yet immunologically activated, points to TNF-NF-κB pathway modulation as a key mediator of shell repair under acidification. Our findings demonstrate that visible shell closure masks underlying structural and mechanical failure, and that immune regulation, rather than simple suppression or activation, critically shapes the repair outcome. These results advocate for multifunctional indicators beyond closure area to assess shell integrity in acidified marine environments.

Animals↗

PubMed1976

The development of the oxygen permeability of the avian egg shell and its membranes during incubation.

The 02-permeability of the avian egg shell and shell membranes is initially low (approximately equal to 0.1-10(-6) ml O2 STP-sec-1cm-2-mmHg-1) during incubation but increases about 10-fold after the first week. This increase correlates with a decline in water content of the membranes. A major increase in colloid osmotic pressure (up to 50 cm Hg) occurs and is the suggested cause for the onset of rapid removal of water from the membranes. A high membrane water content correlates with low O2-permeability and vice versa. The final degree of membrane hydration reached during incubation is independent of ambient humidity; that is, the O2-permeability of the shell and its membranes is controlled by conditions inside the egg. An hypothesis is presented to explain the profound increase in O2-permeability while the rate of water loss from the egg remains stable during incubation. The removal of water from the shell membranes by the increased colloid osmotic pressure will increase the number of gas filled channels in the membranes which in turn will increase the O2-permeability. In spite of the change in water content, the water vapor pressure in the shell membranes will always be very close to that of a free water surface and water loss will hence be determined by the ambient humidity and the porosity of the mineral shell.

Animals↗