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Biomedical subjects

P Turek

Publications and source records attributed to P Turek.

At least 19 recordsLinked to original sources

Analysis of non-crossover bivalents in pachytene cells from 10 normal men.

BACKGROUND: Bivalents with no recombination foci (possible achiasmates) are unable to orient properly on the metaphase plate or to segregate chromosomes to daughter cells. Non-crossover bivalents are known to cause meiotic arrest in various organisms. METHODS: Individual non-crossover bivalents were identified in 886 pachytene cells (19 492 bivalents) from testicular biopsies of 10 normal men. Fluorescence staining combined with centromere-specific multicolour fluorescence in situ hybridization (cenM-FISH) was used to identify mismatch repair gene mutation of human mutL homologue 1 (MLH1) recombination foci along each bivalent synaptonemal complex (SC). RESULTS: A total of 60 autosomal non-crossovers (SCs without an MLH1 focus) were found, and of these, chromosomes 21 (2.1%) and 22 (1.7%) had a significantly higher proportion than chromosomes 11, 12, 19 (each 0.1%), 13 (0.2%), 14 (0.6%), 16 (0.5%) and 15, 17, 18, 20 (each 0.3%) (P < 0.05). Sex chromosome univalents had a frequency of 27%, higher than that observed in any autosomal bivalent (P < 0.0001). CONCLUSIONS: These results suggest that G-group chromosomes and sex chromosomes are most susceptible to having no recombination foci and thus would be more susceptible to non-disjunction during spermatogenesis. This is consistent with previous observations from sperm karyotyping and FISH analysis, which demonstrate that chromosomes 21 and 22 and the sex chromosomes have a significantly increased frequency of aneuploidy compared with other autosomes.

Aged↗

[Molecular study of type 2 von Willebrand disease].

BACKGROUND: von Willebrand disease is an inherited bleeding disorders caused by mutations in the von Willebrand factor gene. We attempted to characterise the phenotype and the genotype in the first five families in Czech Republic affected by this heterogeneous disorder. METHODS AND RESULTS: The level of FVIII was measured by the one stage assay, the vWF:Ag by the immunoelectrophoresis, vWF:RiCo by aggregometry. For the vWF multimer analysis a western blot based technique was used. The vWF binding to FVIII was evaluated by the ELISA method. Two families were classified as the type 2A, one as the type 2B and two as the combined type 1/2N. Based on that knowledge, parts of the vWF gene were selected for genetic analysis. The previously described mutations Arg1374His and Gly1579Arg were identified in two families with the type 2A. In the family with type 2B a substitution Arg1308Cys was detected. In one family with the type 1/2N, two different previously described defects were found on the separate alleles of the vWF gene: a deletion of cytosine 2435 and a polymorphism Arg854Gln. Compound heterzygotes had the type 1/2N phenotype, while a carriers of the deletion had type 1 phenotype. In the second type 1/2N family, only the amino acid substitutions Thr791Me was found explaining the qualitative defect. A mutation underlying the quantitative deficiency needs to be searched for throughout the entire vWF gene. CONCLUSIONS: Based on the characterisation of the phenotype and genotype, five apparently unrelated families with the von Willebrand disease were diagnosed according to the revised classification. Our work represents laboratory basis for further studies into von Willebrand disease in Czech Republic.

Genotype↗

Postchemotherapy ejaculatory azoospermia: fatherhood with sperm from testis tissue with intracytoplasmic sperm injection.

PURPOSE: To define the success of testis sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI) in azoospermic men with a history of chemotherapy. PATIENTS AND METHODS: In a retrospective study, 23 men with ejaculatory azoospermia and a history of chemotherapy underwent TESE in a search for usable spermatozoa. In six patients cryopreserved tissue and in nine patients fresh tissue provided sperm for an ICSI cycle. Histologic analysis of the testis was performed in all patients. The presence or absence of sperm, fertilization rates with ICSI, and final outcomes of pregnancy were recorded. RESULTS: Spermatozoa were found on TESE in 15 (65.2%) of 23 men. On histopathology, the predominant pattern observed was Sertoli cell only (47.8%), followed by hypospermatogenesis (30.4%), mixed (17.4%), and late maturation arrest (4.3%). The fertilization rate was 65.2%, and ongoing/delivered pregnancies occurred in 30.8% of cycles. Six healthy boys and four healthy girls have been born to date. CONCLUSION: Men who are azoospermic and have had prior cytotoxic therapy make up a small subgroup of males with nonobstructive azoospermia. It is important to define and characterize this subgroup and better define their true fertility potential. Approximately two thirds of these men have retrievable testis sperm, which may be used with ICSI to have healthy offspring. This exciting avenue for paternity has heretofore not been available to such patients.

Adolescent↗

Magnetic and electronic properties in novel terpyridine-based nitroxide complexes: strong radical-metal interaction via a pyridyl ring.

Transition metal complexes of 2-[4'-(2,2':6',2' '-terpyridyl)]-(4,4,5,5-tetramethylimidazolinyl-3-oxide-1-oxyl) (terpy-NIT) and 2-[4'-(2,2':6',2' '-terpyridyl)]-(4,4,5,5-tetramethylimidazolinyl-1-oxyl) (terpy-IM) have been prepared. Whereas the pyridyl fragments of the free ligands are in an anti conformation, the complexes are obtained by coordination of two terpyridines in a syn conformation, forming a distorted octahedron around the metal center: [M(terpy-NIT)(2)](ClO(4))(2) (M = Ni(II) 1, Zn(II) 2, Cu(II) 3) and [M(terpy-IM)(2)](ClO(4))(2) (M = Ni(II) 4, Zn(II) 5). The ligands and their complexes have been characterized by FAB-MS, UV-vis, FT-IR spectroscopies, elemental analysis, and by EPR spectroscopy and susceptibility measurements. Single-crystal X-ray diffraction have been performed on the terpy-NIT ligand and on complexes 1, 4, and 5 giving following crystal data: terpy-NIT, monoclinic, P2(1)/c, Z = 4, a = 14.2186(5), b = 12.9129(6), c = 11.704(1) A, beta = 108.615(4) degrees; 1, orthorhombic, P(n a 2(1)), Z = 4, a = 23.6367(6), b = 8.7836(1), c = 24.2748(7) A; 4, monoclinic, P2(1), Z = 1, a = 8.738(1), b = 25.010(1), c = 11.704(1) A, beta = 102.849(3) degrees; 5, monoclinic, P2(1), Z = 1, a = 8.7463(2), b = 25.0833(5), c = 11.8168(3) A, beta = 102.757(3) degrees. For complexes 1 and 3, an antiferromagnetic behavior has been found and parametrized by considering a symmetric magnetic trimer, highlighting a strong intramolecular coupling between the metal and the radicals (average values 2J(M-NIT) = -19.6 K for M = Ni and -22.8 K for M = Cu). In the case of compound 4, an asymmetric magnetic trimer has been used to model the antiferromagnetic interactions (2J(Ni-IM1) = -13.0 K, 2J(Ni-IM2) = -5.6 K). The shape of the EPR spectra of complexes 2, 3, and 5 in solution indicates the intermediate exchange limit, of the order of a few mK, between the two nitroxide radicals through the pyridyl-metal-pyridyl fragment.

Journal Article↗

Towards a better understanding of the magnetic interactions within m-phenylene alpha-nitronyl imino nitroxide based biradicals.

An extensive investigation of the magnetic properties of three series of biradicals (bis-nitronyl nitroxides diNN-R, bis-imino nitroxides diIN-R and mixed INNN-R, where R is either hydrogen, a triple bond or trimethylsilylacetylenic group) has been carried out to give clear values of the intramolecular interactions through the m-phenylene coupling unit with alpha-nitronyl nitroxides (NN) or alpha-imino nitroxides (IN). An EPR study of the molecules in the isolated state is validated by ab initio calculations, which show the respective influence of spin polarisation and molecular conformation on the singlet-triplet gaps. All these results indicate that the triplet state is the ground state for such biradicals, except when the imidazolyl cycles are orthogonal to the phenyl ring. The magnetic properties of the biradicals in the solid state can be rationalised by examination of the short contacts produced between the ONCNO and ONCN groups. EPR studies on single crystals of the H-substituted series have confirmed the presence of a structural distortion for diNN-H whereas diIN-H and INNN-H do not exhibit such a peculiarity. The magnetic behaviour of diIN-H is described well by a four-spins model, with a strong intermolecular antiferromagnetic interaction of -90 K, whereas in the case of the two other compounds, a supplementary contact involves more complex interactions between the dimers. The compound diNN-tmsa exhibits a ferromagnetic intermolecular interaction of +11 K within the dimers, and this could be attributed to the relative disposition of the imidazolyl rings. Compound diNN-tr reveals a chain-like behaviour, whereas diIN-tr shows a predominant antiferromagnetic interaction within the dimers. The values for the intramolecular interactions in the solid state are in good agreement with those found for the isolated molecules.

Journal Article↗

[Direct stent implantation under control of intracoronary ultrasonography. Immediate and late results].

UNLABELLED: Stents of a new generation have been developed, permitting immediate implantation without predilatation of the lesion site. Intracoronary ultrasound (ICUS) has been found useful in precise evaluation of stent expansion and in improvement of long-term therapeutic outcomes. The purpose of the study was to evaluate the safety and efficacy of direct stent implantation using intracoronary ultrasound. The study comprised 30 patients (8 women and 22 men) aged below 70 years with stable and unstable angina pectoris. ICUS was performed at baseline before making a decision about direct stent implantation and during the procedure to evaluate stent expansion. Direct stenting was performed in 26 patients achieving an angiographically and clinically optimal result (100% efficacy). In four patients direct stenting was abandoned because of massive calcifications in the affected artery detected by ICUS at baseline. During the 9-month follow-up recurrence of anginal pain requiring repeated intervention was observed in 3 patients (11.5%). CONCLUSIONS: The use of ICUS prior to direct stenting considerably improves the efficacy of the procedure and long-term therapeutic outcomes. Before wide popularisation of direct stenting under ICUS guidance it is necessary to carry out multicentre randomised clinical studies to verify the expected improvement of long-term results as compared with conventional stent implantation with pre-dilatation.

Adult↗

[Clinical predictors of left ventricular function improvement after percutaneous coronary interventions in patients with ejection fraction below 45%].

BACKGROUND: The value of clinical predictors of left ventricle function recovery after surgical revascularization in patients with decreased ejection fraction is well documented. However, there are no clinical studies assessing factors which can influence left ventricle function in patients with coronary disease and low ejection fraction (LVEF) undergoing percutaneous coronary interventions (PCI). OBJECTIVE: We tried to assess clinical prognostic factors of left ventricle function improvement after PCI in patients with coronary artery disease and impaired LVEF. PATIENTS AND METHODS: We studied patients with LVEF < 45% undergoing PCI. We assessed duration and grade of symptoms of heart failure, angina class and echocardiographic parameters of LV systolic function. After 6 months follow-up LVEF was obtained again. We analyzed influence of baseline clinical factors on LVEF recovery after PCI. RESULTS: We studied 29 patients (mean age 54.4 +/- 11 years) before and after PCI. In the whole group of patients we found significant increase in EF (38.4 +/- 6% vs 50.4 +/- 15%, p = 0.005) at follow up examination. There was significant improvement of EF in patients with NYHA class I or II (from 40.4 +/- 5% to 58.1 +/- 9%, p < 0.0001) as compared to NYHA class III or IV (from 31.4% +/- 9% to 31.8 +/- 11, p = NS). In multivariate regression analysis correlation between NYHA class and LVEF at control examination (beta = -0.54, p = 0.03) was independent from epidemiological variables and baseline LVEF. There was significant increase in LVEF in patients with severe angina (CCS III or IV) as compared to patients without angina (DEF 21.3 +/- 5% vs 7.9 +/- 10%, p = 0.009). There was also higher increase in LVEF in patients with chest pain during balloon inflation (delta EF 17.4 +/- 9% vs 5.7 +/- 9%, p = 0.01). CONCLUSIONS: Mild symptoms of heart failure and independent predictors of left ventricle function recovery after PCI in patients with impaired LVEF. The lack of angina symptoms negatively influence LVEF recovery after PCI.

Adult↗

[Percutaneous renal artery angioplasty--review of current indicators].

The most frequent cause of secondary arterial hypertension is renal artery stenosis. The aetiology of renal artery stenosis is mainly atherosclerotic (75-80%), in the remaining cases fibromuscular dysplasia is the causative factor. Renovascular hypertension has a poorer prognosis than spontaneous because it is more resistant to antihypertensive treatment, signifies an increased risk for the development and progression of malignant hypertension and may lead to irreversible renal dysfunction due to ischaemia. Renal revascularisation has been proved an effective treatment modality in patients with arterial hypertension or renal failure due to renal artery stenosis. However, surgical treatment is associated with the mortality rate of 6-9% due to the concomitant presence of ischaemic heart disease, cerebral and peripheral arteriosclerosis. Percutaneous transluminal renal angioplasty is equally effective in the treatment of arterial hypertension as surgical operation, leading to the improvement or stabilisation of renal function. The advent of renal stenting has markedly changed the efficacy and safety of procedures with PTRA becoming an alternative to surgery. The high efficacy of PTRA is associated with low mortality and relatively few complications as compared with surgical treatment. However, there is continuous discussion concerning the efficacy of percutaneous and surgical renal revascularisation in arterial hypertension. PTRA is currently increasingly frequently recommended in patients with renovascular hypertension not only to control blood pressure but also to protect renal function.

Angioplasty, Balloon↗

Use of enterocin CCM 4231 to control Listeria monocytogenes in experimentally contaminated dry fermented Hornád salami.

The effectiveness of enterocin CCM 4231 in controlling Listeria monocytogenes contamination in dry fermented Hornád salami was examined. Three independent salami treatments were conducted under pilot plant and laboratory conditions. Salamis were produced according to standard technological parameters and stages with ripening for 3 weeks. The reference samples consisted of the meat mixture without either L. monocytogenes or bacteriocin addition. The control sample (CS) consisted of the meat mixture with 1% of L. monocytogenes inoculum (10(8) cfu ml(-1)) added; while the experimental sample (ES) consisted of the same mixture with enterocin CCM 4231 (12800 AU g(-1)) added. Sampling was done on the first day of the experiment, before and after bacteriocin addition for ES, on the second day and after 1, 2 and 3 weeks. The enterocin addition resulted in the reduction of L. monocytogenes by 1.67 log cycle in the ES when compared to the CS immediately after addition of the bacteriocin. Although on the second day, the growth of L. monocytogenes in ES reached 3.38 cfu g(-1) (log 10), a difference of 1.72 log was found between the ES and the CS. After 1 week of ripening, the L. monocytogenes count in the CS reached 10(7) cfu g(-1); while in the ES the count was 10(4) cfu g(-1), a difference which was maintained after 2 and 3 weeks of ripening. However, bacteriocin activity in the ES could not be detected analytically. The meat mixture used did not contain Listeria.

Animals↗

The efficiency of PBPC collections and the relationship to the precollection concentration of CD 34+ cells in blood.

Transplantations of peripheral blood progenitor cells (PBPC) are able to assure a complete haematopoietic and immunologic reconstitution. The efficient mobilization of progenitor cells into peripheral blood is the main factor responsible for quality of the graft as well as timing and technique of collections. The aim of the present paper was to find the optimum time for starting PBPC collections and consequently to minimize the number of procedures required. The study was performed in patients with haematological malignancies using an autologous collection regimen. We attempted to determine a relationship between the concentration of CD 34+ cells in peripheral blood at the beginning of the collection and the number of CD 34+ cells in the leukapheresis product prepared in the standard mode processing 2-3 total blood volumes. We assessed the significance of the CD 34+ cells concentration in peripheral blood for the adequate collection of CD 34+ cells. We also evaluated the time of engraftment in patients after autologous PBPC transplantation whenever possible. The study was performed in 70 patients. Two groups were defined: Group I patients were well mobilized, whereas Group II patients were weakly mobilized. CD 34+ counts, using flow cytometry were found to be useful in predicting the optimal time for collections.

Antigens, CD34↗

The survival of Staphylococcus aureus during the fermentation and storage of yoghurt.

The effect of yoghurt culture Rx on the survival of Staphylococcus aureus CCM 5984 added to milk in various concentrations was observed during the fermentation and storage of yoghurt. The end of the fermentation process (3.5 h) was only accompanied by a slight reduction. During the storage of yoghurt at 4 degrees C a 1-2 log reduction was observed. No Staph. aureus was detected in yoghurt produced from milk contaminated by 10(3) Staph. aureus cells l-1 after 48 h of cold storage. When a concentration of 10(2) Staph. aureus cells was used for milk contamination, the pathogen was not recovered from yoghurt during the fermentation and storage. The fermentation and storage of yoghurt was accompanied by increases in lactic acid and titrimetric acidity, as well as by a decrease in pH value.

Animals↗

[Changes in the microbial picture during the production of poultry salami].

Changes in microbiological parameters during the production of fine poultry salami was monitored in a private poultry-processing plant in Kosice within a period of six months. This product consists of meat paste or mechanically deboned poultry meat (MDPM), which is produced with the help of a Protecon MPB 30 E deboning machine, pork trimmings, water (in the form of crushed ice), salt, spices, and garlic paste. The main raw food material (hand-boned meat and skin from poultry carcasses intended for mechanical deboning), MDPM immediately after production, salted MDPM after its 24-hour-storage and ripening in the chiller, pork trimmings added to MDPM at an amount of 25%, prepared salami emulsion, and the final product (fine poultry salami) were examined for the presence of pathogenic and potentially pathogenic microorganisms. The total plate count, the counts of indicatory microorganisms (Coliforms and Enterococci), Staphylococci, psychrotrophic, proteolytic and lipolytic bacteria were also determined according to the Slovak government regulations. The results of the quantitative microbiological examination are shown in Figs. 1 and 2. It follows from them that the microbial load of poultry skin is considerably higher than that of hand-boned meat. During the deboning process an increase in all microbial parameters (on average by 1-3 radices) was noticed as compared with the raw food material (defrosted poultry carcasses before the mechanical deboning). MDPM contained 10(4)-10(7) CFU/g; the count of coliforms ranged between 10(3) and 10(6)/g; the count of proteolytic and lipolytic bacteria between 10(4) and 10(6)/g; the count of Staphylococci and Enterococci between 10(2) and 10(4)/g. Staphylococcus aureus was discovered in about 50% samples of MDPM in an average concentration of 10(2)/g. In addition to the groups of bacteria listed above, a wide range of potentially pathogenic microorganisms belonging to the family Enterobacteriaceae, especially those of the genus Proteus, Escherichia coli, Citrobacter and Providencia, was also found in MDPM. In four cases Salmonella enteritidis was also detected in the samples of both the skin of chicken carcasses and the MDPM. The nitrate salting mixture added at a concentration of 2% did not significantly reduce the counts of bacteria present in the MDPM. The prepared salami emulsion was very high in all groups of microorganisms, which was also caused by the addition of pork trimmings. This component seems to be a very important source of microbial contamination, showing the following average bacterial counts: total plate count 4.8 x 10(6)/g, the count of psychrotrophic bacteria 1.0 x 10(6)/g, the count of coliforms 7.0 x 10(5)/g, the count of Enterococci 9.2 x 10(3)/g, the count of Staphylococci 3.0 x 10(4)/g, the count of proteolytic microorganisms 2.7 x 10(5)/g, and the count of lipolytic microorganisms 4.2 x 10(5)/g. However, heat treatment of the final product reliably and almost completely devitalized all the bacteria found in the salami emulsion before heat processing. No pathogenic or potentially pathogenic bacteria were detected in any sample of fine poultry salami. Quite a high number of bacteria in the salami emulsion was reduced by heat treatment to a final average value of 10(2)/g.

Animals↗

[Determination of tetracycline in bones, mechanically separated bones and meat using HPLC and microbiological plating methods].

HPLC method with solid phase extraction, and microbiological agar diffusion tests for determination of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in bones, mechanically separated beef and bones were developed. Both mechanically separated bones and bovine flat bones showed the highest yield of tetracyclines by HPLC method. Among tetracyclines, the highest yield was determined in chlortetracycline. The strains of Bacillus subtilis (PH 6.0) and B. stearothermophilus showed the highest sensitivity to the presence of tetracyclines.

Animals↗

[Thrombocyte concentrates prepared from the buffy coat. A modified method].

Since 1992 in the Institute of Haematology and Blood Transfusion thrombocyte concentrates are prepared from buffy coat by the method of Pietersz. The advantages of the above procedure include in particular improvement of the quality of thrombocyte concentrates with regard to their low contamination with leucocytes and erythrocytes. Contemporary resuspended erythrocyte concentrates are devoid of the buffy coat and have a very low leucocyte content. Administration of preparations of this type probably reduces the risk of alloimmunization and leads to a reduced incidence of post-transfusion febrile reactions in recipients. The objective of the submitted work was the implementation and evaluation or several centrifugation procedures for preparation of thrombocyte concentrates from buffy coat with the aim to increase the yield of thrombocytes and to obtain thrombocyte concentrates with a higher number of thrombocytes. From the four mentioned centrifuging procedures for the thrombocyte preparation it is apparent that centrifuging whole blood at 3500 g for 11 minutes with slow acceleration and subsequent spinning of the buffy coat at 555 g for 3 minutes leads to the highest thrombocyte content per transfusion unit of the preparation. Also leucocyte and erythrocyte values present in the preparation were favourable, close to recommendations of the European Council as regards the quality of thrombocyte concentrates.

Cell Separation↗

Determinants of depressed left ventricular ejection fraction in pure mitral stenosis with preserved sinus rhythm.

BACKGROUND AND AIM OF THE STUDY: Although depressed left ventricular ejection fraction is present in a considerable proportion of subjects with pure mitral stenosis (MS), its mechanisms are not clearly identified. The purpose of this study was to identify determinants of depressed ejection fraction in young patients with isolated mitral stenosis in sinus rhythm. METHODS: We retrospectively analyzed 320 records of patients with MS (mitral valve area < or = 2.0 cm2) who underwent invasive diagnostic procedure in our center. Of these 39 subjects aged 20-40 years with isolated MS in sinus rhythm were selected for the final analysis. RESULTS: An ejection fraction not exceeding 50% was found in 12 patients (group A). When comparing group A to the remainder (group B), group A patients had lower left ventricular end-diastolic volume indices (60.5 +/- 21.6 ml/m2 vs. 76.1 +/- 16.1 ml/m2, p = 0.02) and stroke volume indices (28.0 +/- 10.4 vs. 47.9 +/- 12.0, p < 0.001). No significant differences between the groups in patients' age, end-systolic volume index, mitral valve area, mean transmitral gradient, left-sided cardiac pressures, pulmonary wedge pressure, systemic vascular resistance, and cardiac output were found. Indices of left ventricular isovolumic contraction and relaxation as well as end-systolic indices of left ventricular function were also comparable. Group A had significantly higher pulmonary vascular resistance, pulmonary artery pressures, and higher heart rate. An approximate index of left ventricular compliance was significantly lower in group A with similar left ventricular minimal and end-diastolic pressures. CONCLUSIONS: Depressed ejection fraction in pure mitral stenosis with preserved sinus rhythm seems attributable to left ventricular underfilling that appears to be precipitated by other factors in addition to a narrowed mitral orifice, e.g. decreased passive left ventricular compliance and/or altered interventricular interactions.

Adult↗

[Oxytetracycline in the milk of dairy cows with clinical signs of mastitis during the lactation period].

The objective of this study was to determine the oxytetracycline residues in milk from cows with clinical mastitis dosed with two extra-label routes of oxytetracycline administration not only during antibiotic's treatment (5 days), but also six days after treatment by use of a liquid chromatography method of testing with a detection limit of 20 ppb. Both groups of animals were treated once daily for five milkings at 24-hour intervals following morning milkings. Composite milk samples (equal volumes of foremilk from each quarter) were collected during morning and afternoon milkings, mixed together (1:1), and stored until analyzed. Milk samples were analyzed just before the first treatment (0 hour) and ten times at 24-hour intervals. Residue studies in milk cows indicate that oxytetracycline passes into milk. Residues in milk were higher for the cows receiving oxytetracycline by intramammary route (Tab. I) than for the cows receiving oxytetracycline intramuscularly (Tab. II). The highest mean data were 195.68 mg/kg after intramammary infusion (Fig. 2) and 2.74 mg/kg after intramuscular injection (Fig. 3) on the 5th day of the treatment beginning. The analysis data showed that oxytetracycline persisted in milk for as long as two days after both treatments at the concentration 0.03 mg/kg versus 0.02 mg/kg, respectively. No residues were detected in milk of any animal from the 4th day of the cessation of the therapy (Fig. 1) as detected by the HPLC method.

Animals↗