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PubMed1997

Intracanal medicaments: evaluation of the antibacterial effects of chlorhexidine, metronidazole, and calcium hydroxide associated with three vehicles.

The use of an intracanal medicament may be helpful in eliminating remaining bacteria that survived inside root canals after complete chemomechanical preparation. This study evaluated the antibacterial activities of medicaments that act by means of contact, and not by vapor release, against obligate and facultative anaerobic bacteria commonly found in endodontic infections. The medicaments used were 0.12% chlorhexidine gel; 10% metronidazole gel; calcium hydroxide plus distilled water, calcium hydroxide plus camphorated paramonochlorophenol (CPMC); and calcium hydroxide plus glycerin. An agar diffusion test was used, and the zones of bacterial inhibition around each medicament were recorded and compared. The results revealed that calcium hydroxide/CPMC paste was effective against all bacterial strains tested. Chlorhexidine was also inhibitory to all strains. It was about as effective as calcium hydroxide/CPMC paste against most of the strains. Metronidazole also caused inhibition of growth of all obligate anaerobes tested and was more effective than calcium hydroxide/CPMC against two strains. Calcium hydroxide mixed with distilled water or glycerin failed to show zones of bacterial inhibition, probably because of limitations of the agar diffusion test.

Anti-Infective Agents, Local↗
PubMed1998

In vitro determination of direct antimicrobial effect of calcium hydroxide.

The objective of this study was to determine in vitro the time required for calcium hydroxide in direct contact with microorganisms to express its antimicrobial effect. The microorganisms used were: Micrococcus luteus (ATCC-9341), Staphylococcus aureus (ATCC-6538), Fusobacterium nucleatum (ATCC-25586), Pseudomonas aeruginosa (ATCC-27853), Escherichia coli, and Streptococcus sp. The strains were cultivated in Brain Heart Infusion (BHI), with the exception of F. nucleatum (BHI-PRAS). Pure and mixed suspensions of the microorganisms were prepared. Paper cones immersed in these substances were covered with calcium hydroxide paste, and after 0, 1, 2, 6, 12, 24, 48, and 72 h and 7 days they were transferred to an appropriate medium to observe the growth and multiplication of the microorganisms. Incubation was conducted at 37 degrees C for 48 h, according to the requirements of oxygen of each microorganism. The antimicrobial effect of calcium hydroxide was shown to occur after 12 h on M. luteus and F. nucleatum, 24 h on Streptococcus sp, 48 h on E. coli, and 72 h on S. aureus and P. aeruginosa. Mixture II (M. luteus + Streptococcus sp + S. aureus) was sensitive to calcium hydroxide antimicrobial potential after 48 h, whereas mixture I (M. luteus + E. coli + P. aeruginosa), mixture III (E. coli + P. aeruginosa), and mixture IV (S. aureus + P. aeruginosa) were inactivated after 72 h of exposure.

Anti-Bacterial Agents↗
PubMed1999

A comparative study of root-end induction using osteogenic protein-1, calcium hydroxide, and mineral trioxide aggregate in dogs.

Calcium hydroxide has been the material of choice for apexification. The purpose of this study was to compare the efficacy of osteogenic protein-1 and mineral trioxide aggregate with that of calcium hydroxide in the formation of hard tissue in immature roots of dogs. Sixty-four roots of premolars were used. After induction of periradicular lesions, the canals were debrided and filled with calcium hydroxide for 1 wk. After the removal of calcium hydroxide, the root canals received one of the treatment materials in a balanced design. The animals were euthanized 12 wk later. The degree of hard tissue formation and amount of inflammation were evaluated histomorphically. Data were statistically evaluated using ANOVA, chi 2, and Kruskal-Wallis. Mineral trioxide aggregate produced apical hard tissue formation with significantly greater consistency. The difference in the amount of hard tissue produced among the three test materials was not statistically significant. Furthermore, the degree of inflammation was not significantly different between the various test groups.

Aluminum Compounds↗
PubMedDate not supplied

Local tissue irritating effects and adjuvant activities of calcium phosphate and aluminium hydroxide with different physical properties.

Effects of calcium phosphate and aluminium hydroxide adjuvants with different physical properties were examined in guinea pigs for local histopathological reactions, electron-microscopical changes of macrophages and adjuvanticity on total IgG antibody response to subcutaneously administered ovalbumin (OVA) and tetanus toxoid (TT). Calcium phosphate gel (Ca-gel) induced active inflammatory reactions consisting of neutrophils (pseudoeosinophils) and foamy macrophages associated with many multinuclear giant cells for at least 4 weeks. Aluminium hydroxide gel (Al-gel) also elicited granulomatous inflammatory reactions consisting mainly of macrophages with foamy cytoplasm, small lymphocytes and giant cells at the injection sites for up to 8 weeks or longer. Severity of local tissue irritation due to calcium phosphate gel (Ca-gel) was similar to that due to Al-gel except for the duration of the inflammatory reactions. Calcium phosphate suspension (Ca-sus)-induced local reactions completely ceased by the 4th week, while aluminium hydroxide suspension (Al-sus)-induced reactions were seen up to the 8th week. Electron-microscopical observations showed that both Al-gel and Al-sus caused damage of macrophages. The adjuvant activity of Al-gel for OVA or TT was significantly stronger than that of any other adjuvant material, whereas those of Ca-gel and Ca-sus were not seen at a dose of 3 mg calcium phosphate per millilitre. Al-sus-TT at a dose of 3 mg aluminium hydroxide per millilitre induced very low levels of antibody. These results suggest that calcium phosphate adjuvant may not be an useful alternative to Al adjuvant.

Adjuvants, Immunologic↗
PubMed1997

Inactivation of the 22A strain of scrapie agent by autoclaving in sodium hydroxide.

Samples of macerated mouse-brain infected with the 22A strain of scrapie agent were subjected to gravity-displacement autoclaving at 121 degrees C for 30 minutes in the presence of 2 M sodium hydroxide. No infectivity was detectable by mouse bioassay in samples which were either held for an hour at room temperature before autoclaving, or autoclaved immediately after adding the hydroxide. In contrast, all of the mice injected with a control sample, held for an hour in distilled water before autoclaving, developed scrapie. If adopted as a routine decontamination procedure it is recommended that hydroxide-treated waste should be autoclaved in sealed heat-resistant containers which can withstand the pressures involved. This would make the procedure safer for the operator, and avoid autoclave damage through exposure to sodium hydroxide.

Animals↗
PubMed2003

Nickel immobilization in ceramic matrix admixed with waste nickel hydroxide.

WAXS examinations performed with nickel hydroxide samples heated to various temperatures showed that freshly settled wet nickel hydroxide sample contains some amount of crystalline beta-Ni(OH)(2) structure and its share increased when sample was dried during 3 weeks at ambient temperature. However, the share significantly decreased when the sample was dried at 110 degrees C and more so at 250 degrees C. Crystalline phase traces of Ni(OH)(2) disappeared after sample burning at 980 degrees C and instead the distinct presence of crystalline NiO was determined. The above samples were examined for solubility in stoichiometric amount of sulphuric acid diluted with water to pH 1.9 and 2.8. Solubility was determined by measuring nickel ion concentration in leachate by the AAS method. The dissolving rate was found to decrease with the rise of temperature to which the nickel hydroxide samples were heated. The solubility of Ni(OH)(2) sample burnt at 980 degrees C was undetectable during 90 h solubility-testing time likely due to its transformation into sparingly soluble crystalline NiO. The latter is considered to be the reason for effective immobilization of waste nickel hydroxide in ceramic prepared by blending with clay and sintering at 980 degrees C.

Aluminum Silicates↗
PubMed2003

Water-hydroxide exchange reactions at the catalytic site of heme-copper oxidases.

Membrane-bound heme-copper oxidases catalyze the reduction of O(2) to water. Part of the free energy associated with this process is used to pump protons across the membrane. The O(2) reduction reaction results in formation of high-pK(a) protonatable groups at the catalytic site. The free energy associated with protonation of these groups is used for proton pumping. One of these protonatable groups is OH(-), coordinated to the heme and Cu(B) at the catalytic site. Here we present results from EPR experiments on the Rhodobacter sphaeroides cytochrome c oxidase, which show that at high pH (9) approximately 50% of oxidized heme a(3) is hydroxide-ligated, while at low pH (6.5), no hydroxide is bound to heme a(3). The kinetics of hydroxide binding to heme a(3) were investigated after dissociation of CO from heme a(3) in the enzyme in which the heme a(3)-Cu(B) center was reduced while the remaining redox sites were oxidized. The dissociation of CO results in a decrease of the midpoint potential of heme a(3), which results in electron transfer (tau approximately equal 3 micros) from heme a(3) to heme a in approximately 100% of the enzyme population. At pH >7.5, the electron transfer is followed by proton release from a H(2)O molecule to the bulk solution (tau approximately equal 2 ms at pH 9). This reaction is also associated with absorbance changes of heme a(3), which on the basis of the results from the EPR experiments are attributed to formation of hydroxide-ligated heme a(3). The OH(-) bound to heme a(3) under equilibrium conditions at high pH is also formed transiently after O(2) reduction at low pH. It is proposed that the free energy associated with electron transfer to the binuclear center and protonation of this OH(-) upon reduction of the recently oxidized enzyme provides the driving force for the pumping of one proton.

Animals↗
PubMed2006

1H NMR study of the magnetic properties and electronic structure of the hydroxide complex of substrate-bound heme oxygenase from Neisseria meningitidis: influence of the axial water deprotonation on the distal H-bond network.

The substrate and active site residues of the low-spin hydroxide complex of the protohemin complex of Neisseria meningitidis heme oxygenase (NmHO) have been assigned by saturation transfer between the hydroxide and previously characterized aquo complex. The available dipolar shifts allowed the quantitation of both the orientation and anisotropy of the paramagnetic susceptibility tensor. The resulting positive sign, and reduced magnitude of the axial anisotropy relative to the cyanide complex, dictate that the orbital ground state is the conventional "d(pi)" (d(2)(xy)(d(xz), d(yz))(3)); and not the unusual "d(xy)" (d(2)(xz)d(2)(yz)d(xy)) orbital ground state reported for the hydroxide complex of the homologous heme oxygenase (HO) from Pseudomonas aeruginosa (Caignan, G.; Deshmukh, R.; Zeng, Y.; Wilks, A.; Bunce, R. A.; Rivera, M. J. Am. Chem. Soc. 2003, 125, 11842-11852) and proposed as a signature of the HO distal cavity. The conservation of slow labile proton exchange with solvent from pH 7.0 to 10.8 confirms the extraordinary dynamic stability of NmHO complexes. Comparison of the diamagnetic contribution to the labile proton chemical shifts in the aquo and hydroxide complexes reveals strongly conserved bond strengths in the distal H-bond network, with the exception of the distal His53 N(epsilon)(1)H. The iron-ligated water is linked to His53 primarily by a pair of nonligated, ordered water molecules that transmit the conversion of the ligated H-bond donor (H(2)O) to a H-bond acceptor (OH(-)), thereby increasing the H-bond donor strength of the His53 side chain.

Anisotropy↗
PubMed1995

Pharmacokinetic study of zeolite A, sodium aluminosilicate, magnesium silicate, and aluminum hydroxide in dogs.

Zeolite A is a synthetic zeolite which may have therapeutic utility in osteoporotic individuals because of its ability to stimulate bone formation. A study of Zeolite A (30 mg/kg), sodium aluminosilicate (16 mg/kg), magnesium trisilicate (20 mg/kg), and aluminum hydroxide (675 mg) was designed in beagle dogs. The purpose of this study was to compare the oral bioavailability of silicon and aluminum from Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide in dogs. Twelve female dogs received each compound as a single dose separated by one week in a randomized, 4-way, crossover design. Plasma samples were drawn at time 0 and for 24 hours after dosing. The concentrations of silicon and aluminum were determined by graphite furnace atomic absorption. The mean plasma silicon AUC values (+/- S.D.) were 9.5 +/- 4.5, 7.7 +/- 1.6, 8.8 +/- 3.0, 6.1 +/- 1.9 mg.hr/L and the mean plasma silicon Cmax values (+/- S.D.) were 1.07 +/- 1.06, 0.67 +/- 0.27, 0.75 +/- 0.31, 0.44 +/- 0.17 mg/L for Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide respectively. Although mean silicon AUC and Cmax values were elevated when compared to baseline after administration of the silicon containing compounds, only the AUC from Zeolite A reached statistical significance (p = 0.041). The mean plasma silicon Tmax values (+/- S.D.) were 7.9 +/- 6.4, 5.8 +/- 4.6, 6.9 +/- 6.3 and 8.5 +/- 3.4 hrs for Zeolite A, sodium aluminosilicate, magnesium trisilicate and aluminum Hydroxide respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗
PubMed1997

The effect of a calcium hydroxide paste on wound healing and osseointegration of dental implants. A pilot study in beagle dogs.

The aim of this investigation was to evaluate the effect of a new calcium hydroxide suspension (Osteoinductal) on the healing process of endosseous dental implants after placement. The material, composed of 25% calcium hydroxide, 25% Oleum pedum tauri and 50% vaselinum album, was developed with the intention to accelerate and to increase the mineralized bone to implant contact during the healing phase. Eight adult beagle dogs were used in this study. Prior to the beginning of the study the dogs had all mandibular premolars extracted. After the extraction sites had healed for 3 months, implant osteotomies were performed. On one side of the mandibular premolars extracted. After the extraction sites had healed for 3 months, implant osteotomies were performed. On one side of the mandible Osteoinductal was applied into the osteotomies before placement of the implants, whereas the other side did not receive Osteoinductal. A total of 48 implants were placed with two losses during the entire study period. Two dogs were sacrificed 1 week, 2 weeks, 4 weeks and 3 months after implant placement. The specimens were evaluated histologically and histomorphometrically. In the histological evaluation an intense inflammatory reaction towards the calcium hydroxide suspension was found leading to a destruction of the bone surrounding the implants after 1 and 2 weeks. A giant cell reaction against the test material was visible at 4 weeks. At 3 months no inflammatory and no giant cell reaction could be depicted in the test group. The mean direct bone to implant contact or inflammatory tissue to implant contact showed no differences between test and control group for 1 and 2 weeks. Although statistically not significant, there was a clinical significant difference in the mineralized bone to implant contact between test and control group for the last two timepoints (i.e. 4-week specimens: test group 2.3 +/- 0.9%, control group 26.8 +/- 11.1%; 3-month specimens: test group 10.5 +/- 12.7%, control group 60.7 +/- 13.7%). This study indicates that the use of the calcium hydroxide suspension Osteoinductal has a detrimental effect on wound healing and osseointegration of dental implants and cannot be recommended for use with dental implants.

Alveolar Process↗
PubMed2000

Pulp capping with adhesive resin-based composite vs. calcium hydroxide: a review.

The results of some short-term experiments suggest that direct capping of a vital pulp with the modern resin-based composite systems may be as effective as capping with calcium hydroxide. Total cavity etching with 10% phosphoric acid seems to be safe for the exposed pulp, but unless annulled by calcium hydroxide 35% phosphoric acid may be disastrous. For hemostasis and cleaning of the pulp wound both sodium hypochlorite and saline seem suitable, whereas the effectiveness of a 2% chlorhexidine solution is questionable. Although hard-setting calcium hydroxide cements may induce the formation of dentin bridges, they appear not to provide an effective long-term seal against bacterial factors. Within a few years, the majority of mechanically exposed and capped pulps show infection and necrosis due to microleakage of such capping materials and tunnel defects in the dentin bridges. It is unknown whether newer types of resin containing calcium-hydroxide-products will act as a permanent barrier. The cytotoxicity of the resin-based composites and the temperature rise during polymerisation may not be of concern, but microleakage, sensitisation and allergic reactions may pose problems. Based on available data, pulp capping with resin-based composites may be said to be promising, but more and long-term research is mandatory before the method can be recommended.

Acid Etching, Dental↗
PubMed2001

Response of the pulp of dogs to capping with mineral trioxide aggregate or a calcium hydroxide cement.

This study was conducted to observe the response of dogs' dental pulp to mineral trioxide aggregate (MTA) and a calcium hydroxide cement when used as pulp capping materials. After the pulps of 30 teeth were exposed, they were capped with either MTA or a calcium hydroxide cement. Histological analysis was performed 2 months after treatment. Results showed a healing process with complete tubular dentin bridge formation and no inflammation in any of the pulps capped with MTA. On the other hand, only five specimens from the calcium hydroxide cement group formed a complete dentin bridge. In this experimental group, pulp inflammation was observed in all but three cases. In conclusion, MTA exhibited better results than the calcium hydroxide cement for the capping of the pulp in dogs.

Aluminum Compounds↗
PubMed1997

Use of calcium hydroxide for apical barrier formation and healing in non-vital immature permanent teeth: a review.

OBJECTIVE: To review the use of calcium hydroxide for induction of apical barrier formation and healing in immature permanent teeth. INTRODUCTION: Pulp necrosis is a frequent complication of dental trauma in immature permanent teeth. Endodontic treatment of these teeth is often complicated. The walls of the root canals are frequently divergent and the apices immature, making debridement and obturation difficult. The aim of treatment is induction of apical healing which may be defined as apical closure through formation of mineralised tissue and repair of the periapical tissues. Calcium hydroxide is the material of choice for apical barrier formation and healing. RESULTS: The use of calcium hydroxide for apical barrier formation is successful in 74-100% of cases irrespective of the proprietary brand used. The average length of time for apical barrier formation is approximately 5 to 20 months. Control of infection and adequate cleaning of the root canal are very important for apical healing. CONCLUSIONS: While the success rate of apical barrier formation using calcium hydroxide is high, long-term follow-up of these teeth is necessary. Problems such as failure to control infection, recurrence of infection and cervical root fracture may occur. The latter is more frequent in immature luxated teeth with the least root development.

Bacterial Infections↗
PubMed1999

Susceptibility of oral Candida species to calcium hydroxide in vitro.

AIM: The susceptibility of common oral Candida species to saturated aqueous calcium hydroxide solution was studied. METHODOLOGY: The yeast species tested were C. albicans (16 strains). C. glabrata (three strains), C. guilliermondii (three strains), C. krusei (two strains), and C. tropicalis (two strains). At least one reference strain of each species was used; the others were clinical isolates either from persistent apical periodontitis or from marginal periodontitis. The susceptibility of Enterococcus faecalis (ATCC 29212) was studied for comparative purposes. Standardized inocula of the strains were incubated in aqueous calcium hydroxide solution, pH 12.4, for time-periods ranging from 5 min to 6 h. Volumes of 0.1 mL of the test suspension were cultured directly on Brucella blood agar and incubated in air at 37C. The plates were inspected for growth at 24 and 48 h and the colonies were counted. The time required to reduce the number of colony-forming units to less than 0.1% of the initial number was determined for each strain. RESULTS: The sensitivity of the C. albicans strains was generally low, with 16 h of incubation required to kill 99.9% of the colony-forming units. No differences in susceptibility between C. albicans strains isolated from root-canal infections and from periodontitis were found. Both strains of C. tropicalis were killed between 3 and 6 h of incubation, whilst strains of C. guilliermondii were killed after only 1020 min of incubation. All strains of C. glabrata survived 20 min, but not 1 h, of incubation, whilst 13 h were required to kill C. krusei. Compared with E. faecalis, all Candida spp. showed either equally high or higher resistance to aqueous calcium hydroxide. CONCLUSIONS: This study indicates that Candida spp. are resistant to calcium hydroxide in vitro, which may explain the isolation of yeasts from cases of persistent apical periodontitis.

Calcium Hydroxide↗
PubMed2002

Cytotoxicity of resin-, zinc oxide-eugenol-, and calcium hydroxide-based root canal sealers on human periodontal ligament cells and permanent V79 cells.

AIM: The purpose of this study was to determine the cytotoxicity of three different types of root canal sealer on human periodontal ligament (PDL) cells and a permanent hamster cell line (V79 cells). METHODOLOGY: Set specimens from two resin based sealers (AH26 and AHPlus), three zinc oxide-eugenol-based sealers (Canals, Endomethasone and N2) and one calcium hydroxide-based sealer (Sealapex) were eluted with culture medium for 1, 2, 3 and 7 days. Cytotoxicity was judged using tetrazolium bromide reduction assay on human primary PDL cells and V79 cells derived from a Chinese hamster. RESULTS: The results showed that elutes from resin-based, zinc oxide-eugenol-based, and calcium hydroxide-based sealers were cytotoxic to primary human PDL cultures and V79 cells. Calcium hydroxide-based sealer was the least toxic sealer amongst the chemicals tested in both cultures. The cytotoxic response decreased in an order of N2 > Endomethasone > AH26 > AHplus > Canals > Sealapex. CONCLUSIONS: The sensitivity of toxicity depended on the materials tested and the cell culture system used. Thus, the use of both permanent and primary cells is recommended for screening of the cytotoxic effects of root canal sealers. In addition, the results confirmed that root canal sealers constantly dissolve when exposed to an aqueous environment for extended periods, possibly causing moderate or severe cytotoxic reactions. Use of calcium hydroxide-based material as a root canal sealer initially may result in a more favourable response to periradicular tissues.

Administration, Topical↗
PubMed2002

Periapical lesions accidentally filled with calcium hydroxide.

AIM: To evaluate the effect of accidental and voluminous calcium hydroxide overextensions into periradicular lesions and tissues on the prognosis of periapical healing. SUMMARY: Eleven cases with periapical lesions and voluminous calcium hydroxide overextension are presented. Despite literature reports on the deleterious effects of calcium hydroxide extension in the periapical area, none of the endodontic treatments failed and surgical intervention was not indicated. KEY LEARNING POINTS: Extensive extrusion of calcium hydroxide into the periapical tissues does not appear to comprise periapical healing. Despite this finding, the deliberate extrusion of dental materials into the apical tissues is not advocated.

Accidents↗
PubMed2003

Effect of different irrigation solutions and calcium hydroxide on bacterial LPS.

AIM: To evaluate the effect of biomechanical preparation with different irrigating solutions and calcium hydroxide dressing in dog root canals containing bacterial endotoxin (lipopolysaccharides; LPS). METHODOLOGY: One hundred and forty premolar roots from seven dogs were filled with Escherichia coli LPS for 10 days (three roots were lost during histological processing). The following irrigating solutions were used for biomechanical preparation: 1% (group I, n = 20), 2.5% (group II, n = 19) and 5% sodium hypochlorite (group III, n = 19), 2% chlorhexidine digluconate (group IV, n = 20) and physiological saline solution (group V, n = 19). In group VI (n = 20), the LPS solution was maintained in the root canal during the entire experiment and in group VII (n = 20), after biomechanical preparation with saline solution, the root canals were filled with a calcium hydroxide dressing (Calen; control). After 60 days, the animals were sacrificed and the following parameters of periapical disease were evaluated: (a) inflammatory infiltrate, (b) periodontal ligament thickness, (c) cementum resorption and (d) bone resorption. Scores were given and data were analysed statistically with the Kruskal-Wallis and Dunn tests (P < 0.05). RESULTS: Histopathological evaluation showed that groups I-VI had more inflammatory infiltrate, greater periodontal ligament thickening and greater cementum and bone resorption (P < 0.05) compared to group VII, which received the calcium hydroxide intracanal dressing. CONCLUSIONS: Biomechanical preparation with the irrigating solutions did not inactivate the effects of the endotoxin but the calcium hydroxide intracanal dressing did appear to inactivate the effects induced by the endotoxin in vivo.

Alveolar Bone Loss↗
PubMed1983

Carcinogenicity examination of betel quid. II. Effect of vitamin A deficiency on rats fed semipurified diet containing betel nut and calcium hydroxide.

The effect of vitamin A deficiency on the carcinogenicity of betel quid was studied, using long-term feeding of vitamin-A-deficient and -sufficient diets with and without betel nut and calcium hydroxide in ACI rats. A high incidence of focal epithelial hyperplasia was observed in the upper digestive tract (tongue, buccal oral mucosa, esophagus, and forestomach) of rats in the group given the vitamin-A-deficient diet mixed with betel nut and calcium hydroxide. The vitamin-A-deficient group also showed a high incidence of squamous papilloma in the tongue, buccal mucosa, and forestomach. The incidence of hyperplastic lesions of the tongue and buccal oral mucosa was significantly higher in this group than in the group receiving the vitamin-A-sufficient diet with betel nut and calcium hydroxide. These results suggest that the vitamin-A-deficient condition enhanced the growth of epithelial hyperplasia that was due to the administration of the betel quid ingredients. However, vitamin A did not protect against the development of altered liver cell foci, which were frequently seen with a small number of hepatocellular neoplasms in all groups given the diets containing betel nut and calcium hydroxide (both vitamin-A-deficient and -sufficient groups).

Animals↗