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PubMed1986

[Use of quantitative methods in cineangiocardiography: a comparison of 9 methods of motion analysis for the detection of regional function in patients with coronary heart disease].

In order to evaluate the usefulness of various quantitative methods for the assessment of regional left ventricular function, a total of 9 methods (3 hemiaxial models, 1 area model and 5 radial-axes models) were applied to the radiopaque ventriculograms of 16 patients with anterior wall infarction and 13 patients with posterior wall infarction. A series of 17 patients without clinical or angiographic evidence of heart disease were used as control group. While the hemiaxial methods were consistently found to be useful and reproducible, the area method did not provide significant additional information. The diagnostic accuracy was highest with the use of 2 radial-axes methods. The sensitivity and specificity data were 90% to 100% and 70% to 100%, respectively. The remaining 3 radial-axes methods were found to be of limited value since regional wall motion abnormalities were projected to the contralateral wall. Because of this methodological shortcoming these techniques may falsely indicate asynergy in areas with normal contraction patterns. This was reflected by high sensitivity but low specificity values. A feature of the latter 3 methods was the use of the gravity center of the end-systolic frame as the reference point. The position of this reference point is decisively influenced by the extent and localization of asynergy. These findings suggest that methods using the gravity center of the end-systolic frame should not be employed in the evaluation of regional left ventricular function. In general, some quantitative methods for assessing regional left ventricular function require a considerable expense for technical apparatus which is not always justified by the extent to which additional information is gained.

Angiocardiography↗

PubMedDate not supplied

Simple, rapid cleanup method for analysis of aflatoxins and comparison with various methods.

A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ether-methanol-water (94 + 4.5 + 1.5) or chloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (micrograms/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1, M1. Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 micrograms/kg were greater than 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method.

Aflatoxins↗

PubMed1995

[Long-term hemodialysis treatment using femoral vein puncture method (FV-method) as blood access in 12 patients].

It is well known that blood access is essential for long-term hemodialysis treatment. Arteriovenouos fistula (AVF) is the most widely used method. However, this method of access frequently fails (access failure) as a result of stenosis. We attempt simple femoral vein puncture (FV-method) instead of AVF in such patients and have experienced 12 patients who were undergoing hemodialysis treatment using the FV-method, three times a week for more than one year. We devised special needles (18- and 19-gauge) for the FV-method. Generally, we use a 19-gauge needle with 4 side holes. We discuss here the results of 12 patients consisting of 4 males and 8 females with a mean age of 57.9 years, a mean duration of dialysis of 10.0 years, and a mean duration of FV-method of 3.5 years. Their underlying diseases were chronic glomerulonephritis (9 patients), diabetic nephropathy (2 patients) and nephrosclerosis (1 patient). Before the use of the FV-method, AVFs were attempted a man of 3.8 times and an artificial graft, 4 times in 3 patients. Ten patients were outpatients and 2 were inpatients. As for the indications of the FV-method, 11 patients had access failure and another had suffered from heart failure resulting from an over flow of blood through AVF. KT/V, PCR and TACBUN were measured monthly and were within the normal range in almost all of the patients. Concerning complications of the FV-method, hematoma formation after detachment of the needle at the end of dialysis and pain at needle puncture were sometimes noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

[The correlation between the MICs deduced from Showa disk method and the MICs determined by micro-dilution method].

Disc diffusion technique is useful to routine drug susceptibility testing for bacteria in clinical laboratories because of the advantages on simplicity and cost. Kirby-Bauer (KB) method recommended by NCCLS is using widely as a standard method of disk diffusion test, and simply categorize microorganisms as being susceptible, moderately susceptible, intermediate or resistant to different antimicrobial agents by the use of break point. In the determination of breakpoints, the relationship between MICs and clinical results and pharmacokinetics parameters (Cmax, T1/2 and AUC) are significantly considered. However, there are variance of pharmacokinetics among a race, moreover, breakpoint is not yet established in Japan. In report to doctor from clinical laboratory, the MIC might be better than that by breakpoint since there are such problems of breakpoint. Showa disk was developed as mono-disk method being able to deduce MIC from the linear regression between MIC and zone diameter. Therefore, it is thought that Showa disk is one of valuable methods for the routine drug susceptibility testing for bacteria in Japan. There is one problem, which is that MIC deduced by Showa disk is based on the relationship with agar dilution method although the determination method of MIC is going to turn into micro-dilution method, so we compared the MICs deduced from zone diameter of Showa disk method with the MICs determined by broth micro-dilution method by using a challenge set of 110 gram-positive and gram-negative bacteria for 7 antimicrobial agents. The total agreement of MIC within 1-log2 dilution difference was 77% and the correlation coefficient was 0.929. As results, a good relationship was obtained except the results of tetracycline and ofloxacin for beta-lactamase non-producing H. influenzae, and ceftizoxime for E. coli, and K. pneumoniae.

Anti-Bacterial Agents↗

PubMed1996

In vitro susceptibility of 124 Xanthomonas maltophilia (Stenotrophomonas maltophilia) isolates: comparison of the agar dilution method with the E-test and two agar diffusion methods.

The in vitro susceptibility of 124 Xanthomonas maltophilia isolates was tested by four methods: Agar dilution (reference method), E-test, a disk diffusion and a tablet diffusion method. Trimethoprim-sulfamethoxazole had the highest activity against X. maltophilia, followed by a combination of aztreonam-clavulanic acid at different ratios, the ratio 1:1 being the most active with a susceptibility rate of 85% as compared to 2% for aztreonam alone. Addition of the beta-lactamase inhibitor tazobactam to piperacillin enhanced the rate of susceptible isolates from 31% to 53%, Relatively few isolates were susceptible to ciprofloxacin (27%) and gentamicin (9%). Generally, the disk diffusion method had a considerably higher frequency of "very major" discrepancies when compared with the agar dilution method than with the other methods. The susceptibility of X. maltophilia to trimethoprim-sulfamethoxazole and ciprofloxacin could reliably be determined by all the diffusion methods tested, but otherwise the agar dilution method is to be preferred. A standardized and reliable diffusion method for susceptibility testing of X. maltophilia remains to be found. Trimethoprim-sulfamethoxazole must be considered the drug of choice in the treatment of severe X. maltophilia infections. The combination aztreonam-clavulanic acid is promising, but must be proved in a clinical setting.

Anti-Bacterial Agents↗

PubMed1996

Radioimmunological analysis of cyproterone acetate in human serum. Comparison with a gas chromatographic/mass spectrometric method and influence of each method on the outcome of a bioequivalence trial.

Cyproterone acetate (CAS 427-51-0, CPA) is a steroid hormone with antiandrogenic and progestogenic properties, which has been used in the therapy of prostate carcinoma in men, and for the treatment of severe acne and hirsutism in women. The aim of the present study was to compare two equally sensitive analytical methods, a radioimmunoassay (RIA) and a gas chromatographic/mass spectrometric method (GC/MS), for the quantitative determination of CPA in human serum samples and to assess their suitability for bioequivalence trials. To this end, serum samples which had been collected during a study on the bioequivalence oaf two CPA-containing formulations (Androcur 100 and Androcur 50) were analysed using both methods. Basic pharmacokinetic parameters, like Cmax, tmax, t1/2 and AUC were calculated from each data set and corresponding parameters were compared by statistical methods. A comparison of the drug concentration-time curves obtained with both analytical methods revealed that in particular at later sampling times (48 to 120 h post dose) concentration values generated by RIA were slightly higher by about 20-40% than those measured with GC/MS. This indicates the presence of cross-reacting metabolite(s), most likely the 15 beta-hydroxy-cyproterone acetate. Accordingly, the values of Cmax, AUC(0-120 h) and AUC were overestimated by the RIA method by about 10-20%, 5% and 10%, respectively. However, there was a high correlation between corresponding parameters derived from RIA and GC/MS analysis. Although AUC values were slightly overestimated with the RIA method was used, this had no influence on the decision about bioequivalence because the mean ratio of the target variables Cmax and AUC was not affected. The variance of the pharmacokinetic parameters which is relevant for the bioequivalence test were even lower for RIA based values than those calculated after GC/MS analysis. In conclusion, it was found that although the GC/MS method is superior to RIA in terms of specificity, both methods were equally suited to demonstrate the bioequivalence of the two CPA-containing formulations. Thus, in future studies of this kind, the more simple RIA may be used instead of GC/MS.

Adult↗

PubMed1992

A randomized and blinded comparison of three bleeding time techniques: the Ivy method, and the Simplate II method in two directions.

We compared the Ivy bleeding time method and two alternatives of the Simplate II method (incisions in horizontal and vertical direction) with each other, with regard to the sensitivity, the specificity, the costs and the burden for the patient. In the aspirin study an aspirin-induced bleeding defect was used. Seventy-two healthy volunteers were randomized to receive either 500 mg acetylsalicylic acid (ASA) or a placebo. Double blinding was maintained throughout the study. In the anticoagulation study 62 patients participated, who received oral anticoagulants (OAC) for various reasons. All participants received two bleeding time methods. The burden for the participants of each method was screened by a small standard questionnaire. The differences in sensitivity and specificity between the three methods proved minimal. The Ivy method was more often preferred by the participants than the Simplate methods. Since a choice on the basis of sensitivity and specificity appears not possible, we prefer the Ivy method because of lower costs and less burden.

Adult↗

PubMed1989

Validation of a new closed circuit indirect calorimetry method compared with the open Douglas bag method.

New equipment designed for the routine measurement of oxygen uptake (VO2) using a closed circuit method has been validated by comparing it with a standard Douglas bag method. The equipment (The Caloric Measurement Unit, CMU) has been tested in 10 critically ill patients during mechanical ventilation (MV) and in 10 spontaneously breathing healthy subjects. Determinations of VO2 and of the resting energy expenditure (REE) were measured in duplicate with the standard method and once with the CMU. Six additional patients receiving MV were studied with the CMU to evaluate the reproducibility and the effect of FIO2 = 1 vs FIO2 = 0.43 on VO2 measurements. Considering the whole group of 10 patients and 10 subjects, the mean difference of VO2 between both methods was -2 +/- 21 ml/min (95% confidence interval, -11.8 to 7.8 ml/min, p = 0.6) standard deviation. Both methods had a similar reproducibility and the mean difference of VO2 measured at the two different FIO2 with the CMU was -3.2 +/- 11 ml/min (95% confidence interval, -14.7 to 8.4 ml/min, p = 0.5). No statistically significant difference was found between derived REE values obtained from either method. These data show a good correlation between the two methods suggesting that CMU may be used in place of the standard method with the same accuracy in measurement of VO2 even at FIO2 = 1.

Adult↗

PubMed1994

A stereophotogrammetric method for determining in situ contact areas in diarthrodial joints, and a comparison with other methods.

Determination of contact areas in diarthrodial joints is necessary for understanding the state of stress within the articular cartilage layers and the supporting bony structures. The present study describes the use of a stereophotogrammetry (SPG) system [Huiskes et al., J. Biomechanics 18, 559-570 (1985) and Ateshian et al., J. Biomechanics 24, 761-776 (1991)] for determining contact areas in diarthrodial joints, using a surface proximity concept similar to the one used by Scherrer et al. [ASME J. biomech. Engng 101, 271-278 (1979)]. This method consists of evaluating the proximity of the articular surfaces to determine joint contact areas using precise geometric models of the joint surfaces obtained from the SPG system, and precise kinematic data, also obtained from SPG. In this study, the SPG method for determining contact areas is compared to other commonly used methods such as dye staining, silicone rubber casting and Fuji film contact measurement techniques which have been often used and reported by other investigators. The bovine glenohumeral joint and the bovine lateral tibiofemoral articulation (without the meniscus) were used to represent congruent and incongruent joints, respectively. While all the methods yielded consistent contact patterns for the incongruent tibiofemoral articulations, the results for the congruent bovine glenohumeral joints showed that the SPG and Fuji film methods were in better agreement than those obtained from the dye staining and silicone rubber casting methods. The advantages of the new SPG method are that it can be used for intact joints, and used repeatedly and quickly thus making contact-area movement analyses possible [Soslowsky et al., J. orthop. Res. 10, 524-534 (1992)]. The results of this comparison study show that the SPG technique is a reliable and versatile method for determining contact areas in diarthrodial joints.

Animals↗

PubMed1996

Comparison of the hydrophobic grid-membrane filter DNA probe method and the Health Protection Branch standard method for the detection of Listeria monocytogenes in foods.

The standard Health Protection Branch (HPB) method for the detection of L. monocytogenes in foods involves lengthy enrichment, selection and biochemical testing, requiring up to 8 days to complete. A hydrophobic grid-membrane filter (HGMF) method employing a digoxigenin-labelled listeriolysin O probe required 5 days to complete, and included an image-analysis system for electronic data acquisition. A total of 200 food samples encompassing 8 high-risk food groups (soft and semi-soft cheeses, packaged raw vegetables, frozen cooked shrimp, ground poultry, ground pork, ground beef, jellied meats, and pâté) were screened for the presence of L. monocytogenes by the two methods. Overall, 32 (16%) and 30 (15%) of the naturally-contaminated food samples tested positive for L. monocytogenes by the HPB and DNA methods, respectively. The DNA probe method was highly specific in discriminating L. monocytogenes from other Listeria spp. present in 50 of the samples tested. Results showed 94% sensitivity and 100% specificity between the two methods. The HGMF DNA probe method is an efficient and reliable alternative to the HPB standard method for detecting L. monocytogenes in foods.

DNA Probes↗

PubMedDate not supplied

Young smokers' attitudes about methods for quitting smoking: barriers and benefits to using assisted methods.

There is currently little information about how smokers choose a particular method to stop smoking. Young adult smokers rated likelihood of success as the most important criteria for choosing a stop-smoking method but saw only a small difference in likelihood of success between common assisted and unassisted methods. They rated cost, convenience, and quitting on own as other important criteria. Almost all would choose an unassisted method for their next quit attempt. The smokers then rated their probability of using a stop-smoking program or a nicotine patch under various conditions of cost, convenience, and increased likelihood of success. The results showed that the smokers indicated a moderate-high probability of using the two assisted methods under assumptions of convenience and likelihood of success that are currently realistic. However, they were extremely sensitive to cost of the method. When the stop-smoking program or nicotine patch was free, the estimated probability of use was over 50% for all tested conditions; however, at a cost of +25 the estimated probability dropped below 20% for all conditions. Young smokers would be likely to choose assisted methods when attempting to stop if they appreciated the increased likelihood of success with these methods and if the cost was not high.

Administration, Cutaneous↗

PubMed1997

Validation of a simple, manual urinary iodine method for estimating the prevalence of iodine-deficiency disorders, and interlaboratory comparison with other methods.

The measurement of urinary iodine in population-based surveys provides a biological indicator of the severity of iodine-deficiency disorders. We describe the steps performed to validate a simple, inexpensive, manual urinary iodine acid digestion method, and compare the results using this method with those of other urinary iodine methods. Initially, basic performance characteristics were evaluated: the average recovery of added iodine was 100.4 +/- 8.7% (mean +/- SD), within-assay precision (CV) over the assay range 0-0.95 mumol/L (0-12 micrograms/dL) was < 6%, between-assay precision over the same range was < 12%, and assay sensitivity was 0.05 mumol/L (0.6 microgram/dL). There were no apparent effects on the method by thiocyanate, a known interfering substance. In a comparison with five other methods performed in four different laboratories, samples were collected to test the method performance over a wide range of urinary iodine values (0.04-3.7 mumol/L, or 0.5-47 micrograms/dL). There was a high correlation between all methods and the interpretation of the results was consistent. We conclude that the simple, manual acid digestion method is suitable for urinary iodine analysis.

Arsenic↗

PubMed2025

Newly Developed Structure-Based Methods Do Not Outperform Standard Sequence-Based Methods for Large-Scale Phylogenomics.

Recent developments in protein structure prediction have allowed the use of this previously limited source of information at genome-wide scales. It has been proposed that the use of structural information may offer advantages over sequences in phylogenetic reconstruction, due to their slower rate of evolution and direct correlation to function. Here, we examined how recently developed methods for structure-based homology search and tree reconstruction compare with current state-of-the-art sequence-based methods in reconstructing genome-wide collections of gene phylogenies (i.e. phylomes). While structure-based methods can be useful in specific scenarios, we found that their current performance does not justify using the newly developed structure-based methods as a default choice in large-scale phylogenetic studies. On the one hand, the best performing sequence-based tree reconstruction methods still outperform structure-based methods for this task. On the other hand, structure-based homology detection methods provide larger lists of candidate homologs, as previously reported. However, this comes at the expense of missing hits identified by sequence-based methods, as well as providing sets of homolog candidates with higher fractions of false positives. These insights help to guide the use of structural data in comparative genomics and highlight the need to continue improving structure-based approaches. Our pipeline is fully reproducible and has been implemented in a Snakemake workflow. This will facilitate a continuous assessment of future improvements of structure-based tools in the AlphaFold era.

Phylogeny↗

PubMed1995

Method specificity of non-invasive blood pressure measurement: oscillometry and finger pulse pressure vs acoustic methods.

1. The agreement of blood pressure measurements by stethoscope auscultation (SBPa, DBPa-IV and DBPa-V), oscillometry (Dinamap; SBPo, and DBPo) and digital photoplethysmography (Finapres; SBPf, and DBPf) with the graphical analysis of the analogue microphone signals of vascular wall motion sound (SBPg and DBPg) was evaluated in eight healthy subjects in the presence of responses to the intravenous infusion of 1 microgram min-1 isoprenaline. 2. In general, there was good agreement between the SBP/DBP-measurements based on auscultatory Korotkoff-I- and IV-criteria and the reference method; the average method difference in estimating the isoprenaline responses for SBPa-SBPg was: -1.1, 95% CI: -5.4 to 3.1 mm Hg with a within-subject between-method repeatability coefficient (REP) of 11.6 mm Hg and for DBPa-IV-DBPg: 3.5, 95% CI: -0.5 to 6.5 mm Hg, REP: 11.5 mm Hg. The ausculatation of Korotkoff-V substantially overestimated the isoprenaline induced reduction of DBP: method difference DBPa-V-DBPg: -11.3, 95% CI: -17.8 to -4.7 mm Hg, REP: 31.8 mm Hg. 3. Oscillometry yielded good approximations for the SBP response to isoprenaline (average method difference SBPo-SBPg: -2.9, 95% CI: -9.0 to 3.3 mm Hg, REP: 17.6 mm Hg) but was poorly sensitive with regard to the DBP responses: method difference DBPo-DBPg: 6.5, 95% CI: -1.3 to 14.3 mm Hg, REP: 25.7 mm Hg. 4. Whilst the finger pulse pressure agreed well with regard to DBP (method difference for the DBP responses to isoprenaline: DBPf-DBPg: 1.8, 95% CI: -5.1 to 8.6 mm Hg, REP: 18.5 mm Hg) it was rather unsatisfactory with regard to SBP (method difference SBPf-SBPg: -14.1, 95% CI: -28.2 to -0.1 mm Hg, REP: 49.9 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗

PubMed1992

HLA-DQB1 allele typing by a new PCR-RFLP method: correlation with a PCR-SSO method.

We have developed a new PCR-RFLP method for HLA-DQB1 typing. This method was easy to follow, requiring only one DQB1 generic amplification and 5 endonucleases to assign 14 out of 15 HLA-DQB1 alleles. In addition, we determined that by using one generic amplification and two enzymes (Sau96 I and Hae III) it was possible to type the generic specificities: DQw2, DQw4, DQw5, DQw6, and DQw7, DQw8-9, providing a practical alternative for serological HLA-DQ generic typing. We also performed a side-by-side correlation with a PCR-SSO typing method and found an almost 100% concordance between the methods. The limitations of these methods were: 1) the PCR-RFLP method did not allow the differentiation between the HLA-DQB1*0602 and *0603 alleles; 2) the PCR-SSO method gave crosshybridization signals in the detection of *0302 or *0303 alleles. Our results suggested that both methods, PCR-RFLP and PCR-SSO, are useful alternatives for HLA-DQB1 typing.

Alleles↗

PubMed1975

Cutaneous immunohistochemistry. The direct immunoperioxidase and immunoglobulin-enzyme bridge methods compared with the immunofluorescence method in dermatology.

Two immunohistochemical methods, using the enzyme horseradish peroxidase, the direct immunoperoxidase (DIP) and the immunoglobulin-enzyme bridge (IEB) method were applied on 129 skin specimens of 81 patients with lupus erythematosus, bullous pemphigoid, pemphigus vulgaris and rosacea. These methods were compared with each other and with the immunofluorescence (IF) method. The DIP method was preferred to the IEB method because of the greater contrast between the specific staining and the nonspecific staining of the former. The results obtained with both peroxidase methods were comparable with those of the IF method.

Fluorescent Antibody Technique↗

PubMed1997

A new method for direct detection of heparin on surface-modified intraocular lenses. A modification of Jaques' toluidine blue staining method.

BACKGROUND: Examination of surface-bound heparin on synthetic polymers can only be performed by few staining methods. These methods are limited by an only approximate detection of heparin visible at high magnification. Other methods only measure heparin quantitatively (per square dimension) and are rather sensitive to artifacts. Due to its homogeneous staining pattern, the modified toluidine blue staining technique, using a non-protein-based substance, allows examination and analysis of the homogeneity of the monomolecular heparin layer even under critical conditions like scanning electron microscopy. MATERIALS AND METHODS: For critical examination of the heparin layer, this method was used for 5 sterile heparin surface-modified (HSM) monofocal (Pharmacia, 809C, 5 mm optical zone), 2 multifocal PMMA (Pharmacia, 811E, 6 mm optical zone) and 1 standard PMMA intraocular lenses (IOLs; Pharmacia, 809P, 5 mm optical zone). A special mixture containing a sodium borate buffer was used to avoid cross-reactions of toluidine with phenylimines, which permit a covalent surface linkage of heparin to synthetic polymeric materials via reductive amination. This resulted in less coarse-grained complex agglutination. After light and spectral microscopy of the surface of stained IOLs, scanning electron microscopy was performed to investigated the reliability and validity of this modified staining method. RESULTS: All HSM IOLs showed a homogeneous heparin structure and coating, which could be demonstrated even under critical photographic circumstances. CONCLUSIONS: The modification of the original toluidine blue staining method introduced by Jaques in 1943 is a reliable and reproducible technique for the detailed in vitro analysis of surface-bound heparin with a low artifact rate. Because of the detailed detection of heparin on polymeric surfaces, this staining method is recommended for special problems, e.g. in cataract surgery.

Coloring Agents↗

PubMed1986

The unlabeled antibody method: comparison of peroxidase-antiperoxidase with avidin-biotin complex by a new method of quantification.

Upon plotting of areas against optical densities in immunocytochemically stained tissue sections, hyperbolic curves were obtained which could be reduced to two straight lines, one representing variations in stained structures, and the other variations in background. The slopes of the stained structure lines reflected staining intensity independently of total area of stained structure in a section. The ratio of slopes of the stained structure and background lines reflected immunocytochemical sensitivity. A comparison of the peroxidase-antiperoxidase (PAP) method with the avidin-biotin complex (ABC) method showed that at usual antibody dilutions the PAP method was much more sensitive than the ABC method, while at impractically high antibody dilutions it was moderately more sensitive. Once sufficient dilutions of antibodies were reached, staining intensities dropped sharply with the PAP method. On the other hand, the dilution curves were flat with the ABC method. The ABC method consequently appeared unsuitable for estimating variations in concentration of antigen or for distinguishing high or low concentrations of antigen. The ABC method provided a stain for myelin even in the absence of any antibodies.

Animals↗