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Biomedical subjects

Y M Chan

Publications and source records attributed to Y M Chan.

At least 19 recordsLinked to original sources

The effect of milk supplementation on bone mineral density in postmenopausal Chinese women in Malaysia.

Dietary studies often report low calcium intake amongst post-menopausal Malaysian women and calcium deficiency has been implicated as part of the etiology of age-related bone loss leading to osteoporosis. Therefore, the objective of this study was to examine the effectiveness of high calcium skimmed milk (Anlene Gold, New Zealand Milk, Wellington, New Zealand) to reduce bone loss in Chinese postmenopausal women. Two hundred subjects aged 55-65 years and who were more than 5 years postmenopausal were randomized to a milk group and control group. The milk group consumed 50 g of high calcium skimmed milk powder daily, which contained 1200 mg calcium (taken as two glasses of milk a day). The control group continued with their usual diet. Using repeated measures ANCOVA, the milk supplement was found to significantly reduce the percentage of bone loss at the total body compared to the control group at 24 months (control -1.04%, milk -0.13%; P<0.001). At the lumbar spine, the percentage of bone loss in the control group was significantly higher (-0.90%) when compared to the milk (-0.13%) supplemented group at 24 months (P<0.05). Similarly, milk supplementation reduced the percentage of bone loss at the femoral neck (control -1.21%, milk 0.51%) (P<0.01) and total hip (control -2.17%, milk -0.50%) (P<0.01). The supplemented group did not experience any significant weight gain over the 24 months. The serum 25-hydroxy vitamin D level improved significantly (P<0.01) from 69.1 +/- 16.1 nmol/l at baseline to 86.4 +/- 22.0 nmol/l at 24 months in the milk group. In conclusion, ingestion of high calcium skimmed milk was effective in reducing the rate of bone loss at clinically important lumbar spine and hip sites in postmenopausal Chinese women in Malaysia. Supplementing with milk had additional benefits of improving the serum 25-hydroxy vitamin D status of the subjects.

Aged↗

Quality of life in women treated with neoadjuvant chemotherapy for advanced ovarian cancer: a prospective longitudinal study.

OBJECTIVE: The purpose was to examine the outcomes of patients with advanced ovarian cancer treated with neoadjuvant chemotherapy, with a special emphasis on the patients' quality of life (QOL). METHODS: Seventeen patients with advanced ovarian cancer were treated with neoadjuvant chemotherapy based on the extent of disease on computer tomography. All patients received combined platinum/paclitaxel chemotherapy. Debulking surgery was performed after three cycles or six cycles of chemotherapy, depending on the response to the chemotherapy. Patients' QOL was studied over time using European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 and was then compared with that of patients treated with conventional treatment in the previous cohort. RESULTS: The response rate to chemotherapy assessed at three cycles was 82.4%. The rate of optimum debulking to residual disease less than 2 cm after chemotherapy was 76.9%, and 38.5% had no gross residual disease after surgery. The median overall survival was 22.9 months. The median disease-free interval was 13.3 months. The overall QOL improved after chemotherapy and this continued to improve up to 12 months. The other functional scales also showed improvements over time, apart from the initial transient deterioration in the role functioning and cognitive functioning at 3 months after chemotherapy. Patients treated with neoadjuvant chemotherapy seem to have better but statistically insignificant difference in QOL parameters than patients treated conventionally. CONCLUSION: Neoadjuvant chemotherapy is an alternative treatment for patients with advanced ovarian cancer in whom the chance of optimal cytoreduction is low. The patients' overall quality of life and functional status improve after neoadjuvant chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

Symptoms, coping strategies, and timing of presentations in patients with newly diagnosed ovarian cancer.

OBJECTIVE: The purpose was to explore whether health education on symptoms of ovarian cancer would aid in early detection, by examining the relationship between symptoms, coping strategies, and timing of presentation in patients with newly diagnosed ovarian cancer. METHODS: Eighty women were included. A questionnaire consisting of a series of open questions was designed to collect information on the sequence of events from the onset of symptoms to the diagnosis of ovarian cancer. The Coping Response Inventory (CRI) was used to assess the coping strategies. RESULTS: A majority (90.0%) of women with ovarian cancer did have symptoms before the diagnosis. Abdominal pain or discomfort, abdominal distension, a palpable abdominal mass, menstrual, bowel, or urinary symptoms were the commonly reported symptoms. Eight (10.0%) patients were totally asymptomatic prior to the cancer diagnosis. The presence of bowel symptoms was significantly associated with late stage disease. Most of the patients sought medical advice within 2 weeks from the onset of symptoms. There was no association between the presence of any particular symptom(s) and the timing of presentation. There was also no correlation between the coping strategies and stage of disease and timing of presentation. On average, patients with early stage disease saw one more doctor compared to patients with late stage disease before the affirmative diagnosis of ovarian cancer. CONCLUSION: Most patients presented early after the onset of symptoms. Health education in this regard may not be useful for early diagnosis of ovarian cancer.

Adaptation, Psychological↗

Monitoring of serum squamous cell carcinoma antigen levels in invasive cervical cancer: is it cost-effective?

OBJECTIVE: The aim of this study was to assess the cost-effectiveness of serial squamous cell carcinoma antigen (SCC) monitoring in the clinical setting. METHODS: All patients with squamous cell carcinoma of the cervix and SCC measurement from 1994 to 1999 were reviewed. The cost of the investigations, including blood tests, X rays, and computer tomography; and clinic visits were adjusted to 2001 dollars for all cases over the 6-year study period. The effectiveness measure was the number of cases detected by SCC monitoring before the onset of clinical symptoms or abnormal physical examination findings. Altered clinical management due to early detection was considered successful. RESULTS: Two thousand eight hundred fifty-one SCC antigen assays were performed from 384 patients. An elevated pretreatment SCC level was associated with poorer cumulative survival over time (P < 0.05). Fifty-five patients had recurrences, with 10 local and 45 distant recurrences. SCC levels were elevated in 47 patients (85%). The median lead time was 7.8 months. The cost of finding 1 recurrence was US$4750. SCC monitoring does not alter clinical management and has no advantage over clinical examination in detecting local recurrence. Most of the recurrent diseases were detected too late for curative treatment. Only 1 patient, in whom the diagnosis could have been made by clinical examination without SCC monitoring, may have potentially benefited from exenteration. CONCLUSION: Posttreatment SCC monitoring is not cost-effective in the absence of curative treatment for distant spread of disease.

Antigens, Neoplasm↗

Dietary calcium intake in postmenopausal Malaysian women: comparison between the food frequency questionnaire and three-day food records.

The objective of this study was to compare the dietary calcium intakes assessed by a quantitative food frequency questionnaire (FFQ) and the three-day food record method in 230 Chinese postmenopausal women aged 50-65 years in Kuala Lumpur. The results showed that the mean calcium intake from the dietary records was 447+/-168 mg/day and 499+/-211 mg/day from the FFQ. The mean difference in intake by the two methods was 51.3 mg (95% CI = -30.8-77.9; SD = 181.2, P>0.05), which did not differ significantly from zero. Pearson's correlation coefficient of 0.56 was obtained between the two methods. Ninety-five percent of the individuals classified by food records fell into the same or within-one-quartile category when classified by FFQ. Forty-eight percent were classified into the same quartile by both methods. No subjects were grossly misclassified by the FFQ. The FFQ correctly identified subjects with calcium intakes below the Malaysian recommended daily allowance (450 mg/day) with 60% specificity and with 92% specificity for women consuming less than 800 mg calcium/day. In conclusion, the FFQ developed was a useful, rapid clinical tool for assessing calcium intake and identifying postmenopausal Chinese women with low calcium intakes in Malaysia.

Adult↗

Cellular signaling mechanisms underlying pharmacological action of Bak Foong Pills on gastrointestinal secretion.

Bak Foong Pills (BFP, also known as Bai Feng Wan) is an over-the-counter traditional Chinese medicine that has long been used for treating gynecological disorders and improving overall body functions, including gastrointestinal (GI) function. However, the cellular signaling mechanism underlying BFP action, especially on the GI tract, has not been elucidated. In the present study, the human colonic epithelia cell line T(84) was used as a model to investigate the effect of BFP ethanol extract on ion transport in conjunction with the short-circuit current (I(SC)) technique. The results showed that the apical addition of BFP extract produced a concentration-dependent (10-1,000 microg/ml, EC(50) = 120 microg/ml) increase in I(SC). The maximal response was observed at 500 microg/ml with an increase in I(SC) of 24.4 +/- 2.3 microA/cm(2) and apical conductance. The BFP-induced I(SC) was not observed when extracellular Cl(-) was replaced or when treated with Bumetanide (100 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter. The BFP-induced I(SC) was insensitive to the Na(+) channel blocker, amiloride, but partially inhibited by the Cl(-) channel blocker, DIDS (100 microM), and completely blocked by DPC (2 mM) or glibenclamide (1 mM) with a significant reduction in the apical conductance. The BFP-induced I(SC) could be mimicked by forskolin (10 microM), but inhibited by a pretreatment of the cells with adenylate cyclase inhibitor, MDL-12330A (10 microM). Pretreatment with EGTA (5 mM) and thapsigargin (10 microM) decreased the BFP-induced I(SC) by 10%. These results demonstrated that BFP ethanol extract exerted a stimulatory effect on gastrointestinal Cl(-) secretion by predominantly activating adenylate cyclase and apical cAMP-dependent Cl(-) channels, with minor contributions from calcium-dependent Cl(-) channels. The effect of BFP may be explored to treat GI disorders such as constipation.

Adenylyl Cyclases↗

Caspase inhibitors promote the survival of avulsed spinal motoneurons in neonatal rats.

Following ventral root avulsion in neonatal animals, the degeneration of spinal motoneurons occurs by an apoptotic-like morphological pathway. In adult animals, however, the mechanism of degeneration of injured motoneurons is still controversial. Because caspases are important mediators of apoptosis, we have investigated the effects of the caspase inhibitors, benzyloxycarbonyl-Asp(OMe)fluoromethylketone (Boc-D-FMK), and N-acetyl-Asp-Glu-Val-Asp aldehyde (Ac-DEVD-CHO) on the survival of neonatal and adult spinal motoneurons after root avulsion of the C7 spinal cord. In the control neonatal animals, virtually all motoneurons had degenerated by 7 days following root avulsion. Treatment with either 0.5 microg Boc-D-FMK or 1 microg Ac-DEVD-CHO enhanced the survival of motoneurons to 80% and 85% for up to 2 weeks post-injury. By 21 days post-injury, 70% of avulsed motoneurons were still present after Boc-D-FMK treatment, whereas all avulsed motoneurons died after treatment with Ac-DEVD-CHO. In adult animals, neither inhibitor was neuroprotective for motoneurons following root avulsion. In summary, the inhibition of caspases effectively rescued avulsed neonatal motoneurons which are died by apoptotic pathway. By contrast, because caspase inhibitors failed to rescue injured motoneurons in adult animals, their death may occur by a non-apoptotic pathway.

Age Factors↗

Psychosocial adjustment in gynecologic cancer survivors: a longitudinal study on risk factors for maladjustment.

OBJECTIVE: The objective was to describe the change in psychosocial state over time and to identify risk factors for maladjustment in gynecologic cancer survivors. Awareness of these issues is important for planning supportive care services for cancer patients. METHODS: A longitudinal prospective study of patients with newly diagnosed gynecologic cancer using individual patients as their own control was performed. Patients were interviewed after confirmation of the diagnosis and were reassessed at 6 and 18 months after completion of treatment and with no evidence of recurrent disease. Psychological adjustment was measured by self-rating on self-esteem, outlook on life, self-role, and femininity. Neuroticism and anxiety were assessed using a neuroticism score and the Hamilton Anxiety Scale. Depressive symptoms were questioned directly. Social adjustment was assessed by changes in working capacity or work status, leisure activity, marital relationship, and sexual activity. RESULTS: Seventy-four women participated. Adjustment problems did not occur in the majority of patients. Psychosocial adjustment was different for patients receiving different types of treatments. Improvement in feminism (P = 0.050) and neuroticism (P = 0.010) was observed for patients receiving chemotherapy and deterioration was observed in patients treated with surgery. Deterioration in neuroticism was associated with lower education level (P = 0.032). With religious belief, there was better family support and more significant improvement in social activity (P = 0.038). CONCLUSION: Most patients adapted well. Patients at risk for psychosocial maladjustment include those who are treated surgically, less educated, and without religious belief.

Adolescent↗

A longitudinal study on quality of life after gynecologic cancer treatment.

OBJECTIVE: The objective was to describe the pattern of quality of life (QOL) over time and to assess the impact of age, symptoms, disease parameters, and treatment on the overall QOL. METHODS: A longitudinal study on patients with newly diagnosed gynecologic cancer using individual patients as their own control was performed. The 33-item EORTC QLQ-C30(+3) was used as the QOL measure. Patients were assessed before treatment, after completion of treatment, and at 6, 12, and 24 months. Spearman's correlation analyses were performed. A mixed effect model was fitted to the data. Bonferroni pairwise comparisons were used to analyze the different variables. RESULTS: One hundred forty-four women completed the study. Overall QOL improved after the completion of treatment but remained the same throughout the 2 years after treatment. The individual patient's QOL before treatment was insignificant while the impact of treatment on the individual patient was significant in determining QOL after treatment. There was a strong correlation for all time points in most factors, indicating that the global health status, functional scales, and symptom scales exhibit a dependent change over time. Relief in symptoms was associated with improvements in functional scales. The scores on overall QOL were lower for younger patients and for patients treated with chemotherapy than for patients treated with surgery. CONCLUSIONS: Strategies for supportive care need to focus on symptom management. Psychosocial interventions, to be effective, should include all patients and should aim to reduce the impact of treatment on the individual patient.

Adult↗

The use of misoprostol prior to hysteroscopy in postmenopausal women.

BACKGROUND: This study examined whether oral misoprostol exerted a cervical priming effect in postmenopausal women prior to hysteroscopy. METHOD: Thirty-seven patients were randomized to receive either oral misoprostol (400 microg) or placebo (vitamin B(6)) 12 h prior to hysteroscopy. The resistance of the cervix to dilatation was objectively assessed by a cervical tonometer. RESULTS: The mean baseline cervical dilatation (4.2 mm in misoprostol group versus 4.4 mm in placebo group) was similar between the two groups. The mean cumulative force measured (27.7 N in misoprostol group versus 21.8 N in placebo group) was also comparable. None of the patients suffered from any significant side-effects. CONCLUSIONS: These data showed that there were no significant benefits from giving misoprostol pre-operatively in postmenopausal women, and it was concluded that oral misoprostol had no significant cervical priming effect in postmenopausal women.

Cervix Uteri↗

Vaginal misoprostol as medical treatment for first trimester spontaneous miscarriage.

BACKGROUND: Misoprostol is effective for cervical priming prior to suction evacuation in first trimester pregnancy termination. This is the first randomized study to compare vaginal misoprostol versus expectant treatment in women presenting with spontaneous miscarriage. METHODS: Sixty women presenting with spontaneous miscarriage were recruited to the study at the Queen Mary Hospital between 1998 and 1999. They were randomized to group 1: misoprostol; and group 2: expectant management. Women in the misoprostol group received vaginal misoprostol 400 microg on days 1, 3 and 5. The expectant group was followed up according to the same schedule. Suction evacuation was performed if there was excessive bleeding or abdominal pain; or if a gestational sac was detected by transvaginal scan on day 15. RESULTS: Fifty-nine women completed the trial. Those who did not require suction evacuation up to the time of return of normal menstruation were considered to be successful. The incidence of side-effects was comparable between the two groups. Three women in the expectant group and one in the misoprostol group underwent emergency suction evacuation because of excessive bleeding. The mean duration of vaginal bleeding was similar for both groups (14.6 days in the misoprostol group versus 15.0 days in the expectant group). The successful rate in the misoprostol group was significantly higher than that of the expectant group (83.3 versus 48.3%, P < 0.05). CONCLUSION: We recommend repeated vaginal misoprostol 400 microg given on days 1, 3 and 5 as a treatment option for women with first trimester spontaneous miscarriage.

Abortion, Spontaneous↗

A novel 1:1 complex of potassium mikanin-3-O-sulfate with methanol.

Mikanin-3-O-sulfate (1), in the form of its potassium salt, together with mikanin (2) and alpinetin (3) were isolated from Mikania micrantha. The crystal structures of K(1) x CH3OH, 2 and 3 x H2O were established by X-ray crystallography. The potassium ions in K(1) x CHO3H are bridged by O5, O7 and O8 to form a chain of face-sharing KO8 coordination polyhedra, from which the aglycon units are outstretched to form a polymeric molecular column. Adjacent molecular columns are linked by pi-pi stacking between parallel, intercalating aglycon units to form layers matching the (101) family of planes, which are further interconnected into a three-dimensional supramolecular assembly. Sulfation at 3-OH induced better co-planarity and conjugation of the rings.

Asteraceae↗

Solidification and stabilization of asbestos waste from an automobile brake manufacturing facility using cement.

Currently, the generated brake lining waste dust, which contains asbestos as its major component, is disposed of into a secure landfill without any additional treatment. As an alternative to this, solidification/stabilization (S/S) disposal of the dust was investigated using Portland cement alone and Portland cement mixed with activated carbon (AC), as the binders. Toxicity Characteristics Leaching Procedure (TCLP) results on the solidified matrix showed that cement was able to immobilize the heavy metals, Ba, Zn, Cr, Pb, Cu and Fe, to within the limits set by the US EPA for TCLP. Addition of AC to the cement reduced the leaching of heavy metals by an additional 4-24% compared to cement alone. The pH of the TCLP leachate extracted from virgin cement, and from dust treated with cement with or without AC was found to increase to 10.9-12.5 as opposed to an initial value of 4.93 for the TCLP extract for the untreated dust. Results of ANS 16.1 (modified) leach protocol revealed that Ba in cement-treated samples showed the highest leach rate, followed by Zn, Pb, Cr, Cu and Fe. The leach rate of heavy metals decreased with progress in time. Cement mixed with AC exhibited similar leach characteristics, however, the leach rate was lower. The linear relationship between the cumulative fraction leached (CFL) and the square root of leaching time in all cement-based samples indicate that a diffusional process is the controlling transport mechanism for the leaching of the heavy metals. The obtained Leachability Indices (L(i)) of 7.6-9.1 and 8.3-9.5 for cement and cement with AC, respectively, were low but exceeded the guidance value of 6, which clearly indicates that all the heavy metals studied are retained well within solid matrices. Cement-based S/S hardening times increased from 30 to 96 h as the dust content increased from 40 to 70 wt.%. The resulting solid matrices exhibited a compressive strength ranging from 1 to 12 MPa, which was well above the specified limit of 414 kPa for such matrices. An economic analysis indicates that the disposal costs for the dust in the only available secure landfill would increase by 40.3% if one were to go for the cement S/S option. Addition of AC to the cement would escalate this by an additional 43.8%. Although the S/S of brake lining dust using cement effectively immobilized the heavy metals of concern, cost considerations may hinder the commercial adaptation of this technique for waste disposal unless new regulatory demands are implemented.

Asbestos↗

Filamin 2 (FLN2): A muscle-specific sarcoglycan interacting protein.

Mutations in genes encoding for the sarcoglycans, a subset of proteins within the dystrophin-glycoprotein complex, produce a limb-girdle muscular dystrophy phenotype; however, the precise role of this group of proteins in the skeletal muscle is not known. To understand the role of the sarcoglycan complex, we looked for sarcoglycan interacting proteins with the hope of finding novel members of the dystrophin-glycoprotein complex. Using the yeast two-hybrid method, we have identified a skeletal muscle-specific form of filamin, which we term filamin 2 (FLN2), as a gamma- and delta-sarcoglycan interacting protein. In addition, we demonstrate that FLN2 protein localization in limb-girdle muscular dystrophy and Duchenne muscular dystrophy patients and mice is altered when compared with unaffected individuals. Previous studies of filamin family members have determined that these proteins are involved in actin reorganization and signal transduction cascades associated with cell migration, adhesion, differentiation, force transduction, and survival. Specifically, filamin proteins have been found essential in maintaining membrane integrity during force application. The finding that FLN2 interacts with the sarcoglycans introduces new implications for the pathogenesis of muscular dystrophy.

Amino Acid Sequence↗

Female urethral adenocarcinoma arising from urethritis glandularis.

INTRODUCTION: Female urethral adenocarcinoma is extremely rare and more than one tissue of origin has been suggested other than the Skene's gland. Immunohistochemistry with cytokeratins (CK) 7 and 20 is used to define the origin of the tumor. CASE REPORT: A 72-year-old woman presented with a 2-cm polypoid tumor at the external urethral meatus and bleeding. Wide local excision and bilateral inguinal lymphadenectomy were performed. Postoperative convalescence was uneventful. It was a poorly differentiated mucinous adenocarcinoma without direct urothelial involvement. There were focal areas of intestinal metaplasia. The tumor cells were positive for CK 7 and 20 and negative for prostate-specific antigen. DISCUSSION: This case provides supportive evidence that mucinous urethral adenocarcinoma may arise from malignant transformation of urethritis glandularis.

Adenocarcinoma↗

Malignancy of the temporal bone and external auditory canal.

A retrospective study of 18 patients with malignant tumors of the external auditory canal and temporal bone was undertaken to gain an Asian perspective of this rare disease. Of these patients, 15 (83%) had squamous cell carcinoma (SCC) and 61% had stage T3 tumors at presentation. The mean age was 56 years (range 38-82 years). Seven (39%) of the 18 patients had radiation-associated tumors (RATs), and all had undergone radiotherapy for treatment of nasopharyngeal carcinoma. The 1-year cumulative recurrence for the RAT group was 100%, but there was no recurrence in the non-RAT group (P = 0.001). In malignancies of the external auditory canal and temporal bone, a different classification and staging system for patients with RATs may be warranted to better guide treatment strategies.

Adult↗

Could the incidence of postoperative urinary tract infection be reduced by reversing the sequence of vaginal cleansing and urethral catheterization?

Postoperative urinary tract infection (UTI) is a common hospital infection after gynaecological operations. A prospective randomized study was performed to examine whether the incidence of UTI could be reduced by reversing the sequence of vaginal cleansing and urethral catheterization. Subjects were randomly allocated to: (1) urethral catheterization before vaginal cleansing; and (2) urethral catheterization after vaginal cleansing. Urine cultures were performed immediately after the procedures as the baseline, on the day of catheter removal, and two days after catheter removal. Patients were examined daily after the operation for any urinary symptoms and fever. The incidences of preoperative asymptomatic bacteriuria were similar in both groups, seven of 84 in group 1 vs. eight of 83 in group 2. Among those with negative urine culture before the operation, 77 in group 1 and 75 in group 2, there was no significant difference in postoperative bacteriuria at catheter removal (23 vs. 22) and two days later (35 vs. 42). No significant difference was noted in the incidence of UTI (5 vs. 10, P = 0.25), with a trend towards less UTI in group 1. Voiding discomfort was more common, and fever less common in group 1. There were significant associations between urine culture results at three different occasions. Bacteriuria at catheter removal is associated with a 7.2 times risk of bacteriuria two days later, 2.4 times risk of urinary symptoms and 3.2 times risk of UTI. Routine surveillance at catheter removal is not cost-effective. We conclude that postoperative bacteriuria and UTI are common. Reversing the sequence of the procedures cannot reduce the incidence. There is no evidence to change the status quo.

Bacteriuria↗

A gain-of-function screen for genes that affect the development of the Drosophila adult external sensory organ.

The Drosophila adult external sensory organ, comprising a neuron and its support cells, is derived from a single precursor cell via several asymmetric cell divisions. To identify molecules involved in sensory organ development, we conducted a tissue-specific gain-of-function screen. We screened 2293 independent P-element lines established by P. Rorth and identified 105 lines, carrying insertions at 78 distinct loci, that produced misexpression phenotypes with changes in number, fate, or morphology of cells of the adult external sensory organ. On the basis of the gain-of-function phenotypes of both internal and external support cells, we subdivided the candidate lines into three classes. The first class (52 lines, 40 loci) exhibits partial or complete loss of adult external sensory organs. The second class (38 lines, 28 loci) is associated with increased numbers of entire adult external sensory organs or subsets of sensory organ cells. The third class (15 lines, 10 loci) results in potential cell fate transformations. Genetic and molecular characterization of these candidate lines reveals that some loci identified in this screen correspond to genes known to function in the formation of the peripheral nervous system, such as big brain, extra macrochaetae, and numb. Also emerging from the screen are a large group of previously uncharacterized genes and several known genes that have not yet been implicated in the development of the peripheral nervous system.

Animals↗