Biomedical subjects

K L Chen

Publications and source records attributed to K L Chen.

At least 19 recordsLinked to original sources

PubMed2005

Lipoprotein profiles and components in Tsaiya ducks under ad libitum feeding and fasting.

This study investigated lipoprotein compositions and distribution in Tsaiya ducks under ad libitum feeding and fasting. The study was conducted on each of thirty Tsaiya ducks over two 4-week periods. Each of the 30 Tsaiya ducks was randomly allocated into an ad libitum feeding group or a 3-day fasting group during the growing period (8-12 weeks old) and during the initial laying period (26-30 weeks old; 10-14 weeks after the onset of laying), respectively. Experimental results indicated that HDL (high-density lipoprotein) is the primary lipoprotein species in growing ducks but that in laying ducks the major population of lipoprotein is VLDL (very low density lipoprotein). Protein and cholesteryl ester were identified as the major components of HDL during both periods; triacylglycerol (TG) was the largest proportion of VLDL in both periods. In laying ducks VLDL contains more TG than in growing ducks; VLDL particle sizes in laying ducks were larger than in growing ducks. Fasting significantly decreased VLDL levels during both periods. The TG content in most lipoproteins was also decreased by fasting during both test periods. In contrast, the cholesteryl ester and free cholesterol in most lipoproteins were increased by fasting. The particle size of HDL and VLDL also decreased during fasting. This study indicated that lipoprotein profiles and components in Tsaiya ducks during the laying period were different from during the growing period and were affected by fasting.

Animal Nutritional Physiological Phenomena↗

PubMed2005

Caponization and testosterone implantation effects on blood lipid and lipoprotein profile in male chickens.

To understand the role of lipid metabolism in increasing body fat accumulation after caponization of male chickens, trials were conducted to determine the effects of levels of testosterone implantation on lipoprotein composition. Male chickens were caponized at 12 wk and selected at 16 wk for a 10-wk feeding experiment. Fifteen male and 15 caponized (capon) chickens were used in trial 1. Ten sham operated chickens (sham) and 40 capons were randomly divided among 4 treatments in trial 2; the treatments were as follows: implantation of cholesterol (1.62 mm i.d. x 3.16 mm o.d., 9.24+/-0.36 mg) or implantation of testosterone at low (1 mm i.d. x 3 mm, o.d., 5.88+/-0.23 mg), medium (1.62 mm i.d. x 3.16 mm, o.d., 9.81+/-0.17 mg), or high (2 mm i.d. x 4 mm, o.d., 16.7+/-0.24 mg) dose. The results of trial 1 showed that caponization decreased (P < 0.05) blood testosterone concentrations and increased (P < 0.05) abdominal fat weight and relative abdominal fat weight in capons. Caponization also increased low density lipoprotein (LDL), high density lipoprotein (HDL), LDL protein, and HDL protein and decreased LDL-free cholesterol (LDL-FC), HDL-FC, and HDL-phospholipid (HDL-PL) percentages (P < 0.05). In trial 2 capons implanted with increasing testosterone levels exhibited proportional increases in blood testosterone concentration, although blood testosterone concentration in implanted capons were not fully restored to those of the sham group. High dose testosterone implantation inhibited abdominal fat accumulation and increased glucose and glycerol concentrations compared with the cholesterol implantation. Caponization of male chickens decreased the androgen level and increased the blood triacylglyceride content. Caponization also changed the lipoprotein profiles, which resulted in increased lipid storage capacity. The testosterone concentration, therefore, must achieve threshold concentrations to inhibit lipid accumulation in the testosterone implanted capon.

Animals↗

PubMed2004

Effects of supplemental copper and chromium on the serum and egg traits of laying hens.

1. This study investigated the effects of supplemental copper and chromium on the serum and egg traits of laying hens using 144 forty-five-week-old White Leghorn layers. The hens were randomly assigned into 9 groups to conduct this 3 copper (0, 125 and 250 mg/kg as copper sulphate) x 3 chromium (0, 800 and 1600 microg/kg as chromium picolinate) factorial trial. 2. Egg yolk cholesterol was significantly reduced by supplementary copper (Cu) and chromium (Cr) and there was an interaction between Cu and Cr supplementation. Egg production, egg weight, eggshell strength and eggshell thickness were not influenced by Cu or Cr supplementation. 3. Serum cholesterol concentration was decreased by Cu supplementation and very low-density lipoprotein (VLDL) was reduced markedly by both Cu and Cr. On the other hand, high-density lipoprotein (HDL) was significantly increased by Cu and Cr. Interaction occurred between Cu and Cr in the VLDL and HDL parameters. Supplmentary Cu also reduced VLDL-cholesterol (VLDL-C) and enhanced HDL-cholesterol (HDL-C), while supplemental Cr had a contrary effect on these two parameters. 4. If minimum egg cholesterol content is the criterion, this study suggests that 125 mg/kg of Cu together with 800 to 1600 microg/kg of Cr provide adequate supplementary concentrations for laying hens.

Animal Feed↗

PubMed2004

Use of a molar clamp to isolate two adjacent single-rooted teeth: a clinical aid.

AIM: To emphasize the importance of rubber dam isolation in root canal treatment and to present a technique to simultaneously isolate two single-rooted teeth using a molar clamp. SUMMARY: Isolation of two adjacent teeth with inadequate tooth structure is a challenge. The split-dam technique or using two clamps have drawbacks. This report presents a technique to simultaneously isolate two adjacent single-rooted teeth that are difficult to isolate by conventional methods. Its advantages are efficiency, reduction of radiation exposure, better access, good visibility and isolation. KEY LEARNING POINTS: The basis of this technique is to isolate two teeth as two roots of a molar tooth. The indications for this technique are two adjacent prepared crowns and crownless roots. The appropriate molar clamp can be selected on the basis of the mesial-distal clamp jaw distance being equal to the mesial-distal spacing of the two roots. The buccal-lingual jaw distance of the clamp should be smaller than the dimension of the roots to provide adequate retention.

Humans↗

PubMed2001

Novel transformations of gamma-silyl nitro compounds.

Introduction of a gamma-silyl group into nitro compounds of dihydrobenzofuran, dihydrobenzo[b]thiophene, and dihydrofuran allowed new transformations to take place in the presence of a Lewis acid to give the corresponding alpha,beta-unsaturated oximes or multisubstituted dihydrofurans, respectively, in good to excellent yields.[reaction: see text]

Journal Article↗

PubMed2001

Effects of chromium nicotinate on performance, carcase characteristics and blood chemistry of growing turkeys.

1. The objective of this trial was to study the effects of chromium nicotinate (Cr) supplementation on the performance, carcase characteristics and blood constituents of 9 to 22 week-old male turkeys. 2. Fifty-four 8-week-old male turkeys weighing 2.9 +/- 0.28 kg were allocated at random into 9 groups with 3 dietary treatments and 3 replicates. The dietary treatment was different dietary concentrations of chromium in the basal diet, to provide 0 (control), 1 or 3 mg/kg. The feeding trial lasted for 14 weeks. 3. Results showed that 1 mg/kg chromium supplementation significantly improved weight gain and food intake at 9 to 18 weeks of age but did not significantly influence performance at 19 to 22 week of age. The breast and thigh muscle were significantly increased in birds receiving 1 mg/kg chromium supplementation but were decreased by 3 mg/kg of supplementation. 4. Dietary chromium supplementation did not significantly influence other serum constituents, including insulin, HDL, VLDL+LDL, HDL-C, VLDL-C+LDL-C, total protein, albumin, and gamma-globulin at 18 and 22 weeks of age. 5. The serum triacylglycerol (TG) and uric acid contents were significantly increased, while glycerol and alpha-globulin were significantly reduced by 3 mg/kg chromium supplementation. However, 1 mg/kg chromium supplementation significantly reduced serum cholesterol and glycerol at 18-weeks old. At 22 weeks of age, 1 mg/kg chromium supplementation significantly increased serum glucose and decreased the uric acid concentration whereas 3 mg/kg chromium supplementation significantly increased the creatinine concentration and decreased beta-globulin concentration.

Animal Feed↗

PubMed2001

Oral treatment of mule ducks with arsenicals for inducing fatty liver.

The aim of this study was to determine the dosage and the compounds of arsenic that induce fatty liver in mule ducks and also to investigate their effects on tissue residues. One hundred four ducks, 8 wk old, were randomly selected for one of six dietary treatments in Trial 1 or one of seven dietary treatments in Trial 2. Different levels of roxarsone were administrated: 0, 10, 20, 30, 40, or 50 mg/d, respectively, in Trial 1. In Trial 2, the experimental treatments were of the same level (11.36 mg/d) with different sources of arsenic that included the control without As, roxarsone (3-nitro-4-hydroxyphenylarsonic acid), arsanilic acid, phenylarsonic acid, O-nitro-phenylarsonic acid, As2O3, or As2O5. Both trials lasted 3 wk, with 1 wk on the treatment followed by 2 wk of withdrawal. Results in Trial 1 showed that a dose of 40 mg roxarsone/d increased liver weight and caused fatty liver, whereas administration of 50 mg/d was lethal. In Trial 2, administration of arsenic (11.36 mg/d) for 1 wk significantly depressed feed intake in the roxarsone, As2O3, and As2O5 groups (P < 0.05), whereas the treatment significantly decreased only live weight gain in the roxarsone group (P < 0.05). Administration of roxarsone alone increased (P < 0.05) serum cholesterol (CHOL), albumin (ALB), and total protein (TP), whereas only As2O3 among treatments significantly decreased serum triacylglycerol (TG) concentration (P < 0.05). In the roxarsone, arsanilic acid, and phenylarsonic acid groups, serum high density lipoprotein (HDL) decreased to a greater extent (P < 0.05), and arsanilic acid treatment significantly increased the very low density lipoprotein (VLDL) (P < 0.05). After 2 wk of withdrawal, liver weights and relative liver weights were heavier in the treatment groups of roxarsone, As2O3, and As2O5 as compared to the control (P < 0.05). Levels of CHOL, TG, TP, and ALB were significantly higher in the groups treated with As2O3 or As2O5 as compared to the control (P < 0.05). The roxarsone and arsanilic acid treatments significantly decreased HDL and increased VLDL in plasma (P < 0.05). The creatine kinase (CK) level in the roxarsone, As2O3, and As2O5 groups was significantly higher compared to the control group (P < 0.05). Among the As sources, roxarsone, As2O3, and As2O5 caused fatty liver in mule ducks.

Administration, Oral↗

PubMed2001

[Two complementary dominant genes controlling apomixis in genus Citrus and poncirus].

Apomixis is very common in Citrus genus and its related genus. Two monoembryonic tangerine varieties (C. reticulata Blanco) Clementine and Wilking were used as seed parents to cross with four polyembryonic orange varieties [C. sinensis (L.) Osbeck]. Both sexual and apomictic progenies were found in each F1 population with different segregation ratios. In a total of 74 Wilking progenies, 23 were monoembryonic and 51 polyembryonic and the ratio of sexual and apomictic progenies was about 1:2 tested either in each individual cross or in the whole Wilking cross combionations. In Clementine progenies, 84 were monoembryonic and 71 polyembryonic and the ratio was about 1:1 tested either in each individual cross or in the whole Clementine cross combionations. According to the results together with other data published, a possible apomixis controlling mechanism was proposed, which involves two complementary dominant genes named as A1 and A2 that control apomixis in genus Citrus and Poncirus. Trees of genotype A1-A2-, except for homozygous of dominant gene A1 (which is lethal), can produce apomixis seeds. And those of other genotypes will produce sexual seeds. The segregation and recombination of these two genes accorded with Mendel's genetic laws. The proposed mechanism could explain genotypes controlling polyembryony-monoembryony existing both in nature species and artificial hybridization progenies as well as most of the known hybridization results.

Citrus↗

PubMed2001

[GnT-V overexpression in human hepatocarcinoma cells affects its migration and expression of cell adhesion molecules].

The purpose of this paper is to study the effect of N-acetylglucosaminyltransferase V (GnT-V) overexpression on the migration of 7721 cells and its mechanism. The abilities of migration of both 7721 cells transfected with GnT-V cDNA and 7721 cells transfected with pcDNA3 was detected, the expressions of integrin and E-cadherin which are important adhesion molecules on surface membrane and closely related to the abilities of invasion and metastasis. Cell migration abilities were measured by the agarose drop explant method. Flow cytometric analysis (FACS) was applied to determine the relative amounts of integrin alpha 5 and beta 1 subunits on the cell surface while RTPCR was carried out to determine the expression of their mRNA. The expression of E-cadherin was examined by the immunocytochemical ABC method. Western blot analysis was carried out to examine the expression of beta-catenin. GnT-V overexpression enhanced evidently the migration ability of 7721 cells and increased the amount of integrin alpha 5 subunit to 2.9 times of that of control while the amount of beta 1 subunits was not significantly changed. Besides, the expressions of E-cadherin and beta-catenin were enhanced at different levels in GnT-V/7721 cells compared with mocked. The results suggested that the overexpression of GnT-V related to the production of N-linked sugar chains could promote the expressions of integrin, E-cadherin and beta-catenin on 7721 cells so that the migration ability of tumor cells was enhanced.

Cadherins↗

PubMed2000

Effect of roxarsone inclusion in the diet on the performance and hepatic lipid metabolism of laying Tsaiya duck.

1. The aim of this study was to examine the effects of roxarsone (3-nitro-4-hydroxyphenylarsonic acid) inclusion in the diet on the performance, liver function and lipid metabolism in the liver of laying Brown Tsaiya ducks. 2. Sixty 36-week-old laying ducks were selected and allocated at random into 4 dietary treatments with 3 replications for each treatment. Feeding was for 7 weeks with 3 weeks of experimental diets followed by a 4 week withdrawal period. The experimental diets were supplemented with 0, 50, 100 and 300 mg/kg roxarsone, respectively 3. Dietary inclusion of 50 or 100 mg/kg roxarsone did not significantly promote performance. Inclusion of 300 mg/kg significantly depressed (P<0.05) performance, liver weight and content, serum triacylglycerol (TG), serum nonesterified fatty acid (NEFA) and increased (P<0.05) cholesterol, creatine kinase (CK) and aspartate aminotransferase (AST) in the serum at the end of 3 weeks on the experimental diet. 4. Laying characteristics returned to normal 4 weeks after withdrawal of roxarsone. The liver weight, fat and TG in the liver and serum concentrations of TG, NEFA, high density lipoprotein (HDL) and AST increased significantly (P<0.05), while the level of very low density lipoprotein (VLDL) decreased (P<0.05) at the end of the withdrawal period. More prominent vacuolised hepatic fatty cells were observed in laying ducks treated with 300 mg/kg of roxarsone.

Animals↗

PubMed1999

Duplications and de novo deletions of the SMNt gene demonstrated by fluorescence-based carrier testing for spinal muscular atrophy.

Approximately 95% of individuals with spinal muscular atrophy (SMA) lack both copies of the SMNt gene at 5q13. The presence of a nearly identical centromeric homolog of the SMNt gene, SMNc, necessitates a quantitative polymerase chain reaction approach to direct carrier testing. Adapting a radioactivity-based method described previously, multiplex polymerase chain reaction was performed using fluorescently labeled primers followed by analysis on an ABI 373a DNA sequencer. The SMNt copy number was calculated from ratios of peak areas using both internal and genomic standards. Samples from 60 presumed carriers (50 parents of affected individuals and 10 relatives implicated by linkage analysis) and 40 normal control individuals were tested. Normalized results (to the mean of five or more control samples harboring two copies of the SMNt gene) were consistently within the ranges of 0.4 to 0.6 for carriers (one copy) and 0.8 to 1.2 for normal controls (two copies), without overlap. Combining linkage analyses with direct carrier test results demonstrated de novo deletions associated with crossovers, unaffected individuals carrying two SMNt gene copies on one chromosome and zero SMNt gene copies on the other chromosome, and unaffected individuals with three copies of the SMNt gene. This report demonstrates that fluorescence-based carrier testing for SMA is accurate, reproducible, and useful for genetic risk assessment, and that carrier testing may need to be combined with linkage analysis in certain circumstances.

Centromere↗

PubMed1999

Ataxin 1 and ataxin 3 in neuronal intranuclear inclusion disease.

Neuronal intranuclear inclusion disease (NIID) is a multisystem neurodegenerative disorder characterized by large intranuclear aggregates in neurons of the central and peripheral nervous system. These ubiquitinated intranuclear inclusions are morphologically similar to the intraneuronal aggregates that have been identified in the CAG/polyglutamine expansion diseases. As rare aggregates in NIID contain a polyglutamine epitope, we further investigated the relationship between this disease and the CAG/polyglutamine expansion diseases. Here, we show that ataxin 1 and ataxin 3 proteins are recruited into aggregates in NIID in the absence of a CAG expansion in the SCA1 and SCA3 genes. These data support an association of NIID with the polyglutamine disorders and provide evidence of in vivo recruitment of proteins with polyglutamine tracts into intraneuronal aggregates.

Adult↗

PubMed1999

Determination of total arsenic concentrations in nails by inductively coupled plasma mass spectrometry.

The analysis of trace elements in biological samples will extend our understanding of the impact that environmental exposure to these elements has on human health. Measuring arsenic content in nails has proven useful in studies evaluating the chronic body burden of arsenic. In this study, we developed methodology with inductively coupled plasma-mass spectrometry (ICP-MS) for the determination of total arsenic in nails. We assessed the utility of the washing procedures for removing surface contamination. Four types of preanalysis treatments (water bath, sonication, water bath plus sonication, and control) after sample decomposition by nitric acid were compared to evaluate the digestion efficiencies. In addition, we studied the stability of the solution over 1 wk and the effect of acidity on the arsenic signal. Arsenic content in the digested solution was analyzed by using Ar-N2 plasma with Te as the internal standard. The results suggest that washing once with 1% Triton X-100 for 20 min for cleaning nail samples prior to ICP-MS analysis is satisfactory. Repeated measurement analysis of variance revealed that there was no significant difference among the various sample preparation techniques. Moreover, the measurements were reproducible within 1 wk, and acidity seemed to have no substantial influence on the arsenic signal. A limit of detection (on the basis of three times the standard deviation of the blank measurement) of 7 ng As/g toenail was achieved with this system, and arsenic recoveries from reference materials (human hair and nails) were in good agreement (95-106% recovery) with the certified/reference values of the standard reference materials. ICP-MS offers high accuracy and precision, as well as high-throughput capacity in the analysis of total arsenic in nail samples.

Arsenic↗

PubMed1997

Proteolipid protein is necessary in peripheral as well as central myelin.

Alternative products of the proteolipid protein gene (PLP), proteolipid protein (PLP) and DM20, are major components of compact myelin in the central nervous system, but quantitatively minor constituents of Schwann cells. A family with a null allele of PLP has a less severe CNS phenotype than those with other types of PLP mutations. Moreover, individuals with PLP null mutations have a demyelinating peripheral neuropathy, not seen with other PLP mutations of humans or animals. Direct analysis of normal peripheral nerve demonstrates that PLP is localized to compact myelin. This and the clinical and pathologic observations of the PLP null phenotype indicate that PLP/DM20 is necessary for proper myelin function both in the central and peripheral nervous systems.

Adolescent↗

PubMed1996

No intermolecular interaction between the large hepatitis delta antigens is required for the secretion with hepatitis B surface antigen: a model of empty HDV particle.

The large delta antigen (LDAg) of hepatitis D virus (HDV), which is similar to the small delta antigen (SDAg), except it has 19 additional amino acids and an isoprenylation signal at the C-terminus, is crucial for interacting with hepatitis B surface antigen (HBsAg) to form a mature virion of HDV. Previous studies indicated that the LDAg alone, but not SDAg, can interact with HBsAg to form an empty particle. However, no evidence yet shows whether the intermolecular interaction of LDAg is necessary for forming an empty HDV particle. By cotransfection of plasmids encoding deletion or isoprenylation-negative mutants of LDAg with a plasmid encoding HBsAg into human hepatoma cells, we demonstrated that (i) the isoprenylation-negative LDAg cannot be secreted, (ii) the coiled-coil domain-deleted LDAg retains the secretion capability, (iii) the isoprenylation-negative LDAg can neither cosecrete with isoprenylation-positive LDAg nor suppress its secretion, and (iv) an intermolecular interaction between LDAgs is unlikely required for secretion. A hypothetical model of empty HDV particle containing HBsAg with isoprenylated LDAgs, which are probably present in a singular form, was then proposed.

Hepatitis Antigens↗

PubMed1996

Complete nucleotide sequence of the genome of Japanese encephalitis virus ling strain: the presence of a 25-nucleotide deletion in the 3'-nontranslated region.

The complete sequence of the genome of the Japanese encephalitis virus (JEV) Ling strain isolated from the brain of a patient in Taiwan in 1965 was cloned by using the reverse transcription-polymerase chain reaction method. Seven overlapping cDNA clones that span the entire virus genome were isolated and sequenced to determine the complete nucleotide sequence, which is 10,951 nucleotides in length. As reported for three other JEV strains (Beijing-1, SA-14, and JaOArS982), the Ling strain contains 95 nucleotides in the 5' nontranslated region (NTR), followed by a single open reading frame of 10,296 nucleotides. However, the length of the 3' NTR of JEV Ling is 560 nucleotides, 25 nucleotides shorter than that of other JEV strains sequenced to date. Comparison of nucleotide and amino acid sequences among these four JEV strains showed that nucleotide (amino acid) sequence divergence in the translated region varied from 1.25% to 3.27% (0.49-1.63%). The nucleotide (amino acid) divergences between the Ling and Beijing-1 strains were 1.25% (0.87%) and between the SA-14 and JaOArS982 strains were 1.42% (0.49%). These values are lower than those found between the Ling and SA-14 [2.44% (1.02%)] or the Ling and JaOArS982 strains [2.84% (0.93%)], as well as those between Beijing-1 and SA-14 [3.14% (1.60%)] or Beijing-1 and JaOArS982 [3.27% (1.63%)] strains. Sequence comparisons of subregions of the genomes i.e., structural genes, nonstructural genes, or individual genes, showed divergence similar to that obtained by comparing the entire sequence. It is likely that the JEV sequence divergence between two human isolates or between two mosquito isolates is lower than that between a human isolate and a mosquito isolate.

Aedes↗

PubMed1994

Partial nucleotide sequence of Japanese encephalitis virus ling strain genome and comparison of the encoded structural proteins and nonstructural protein NS1 among Japanese encephalitis virus strains.

Approximately 4000 nucleotides of the 5'-terminal portion of Japanese encephalitis virus (JEV) Ling strain genome were cloned and sequenced. This nucleotide sequence and its encoded C-PrM-E-NS1 polyprotein sequences were also compared with the corresponding sequences of other JE virus strains. Results demonstrated that the nucleotide sequence homology varied from 97.1 to 99.3% and the amino acid homology 98.6 to 98.9%. Based on homology, the Ling strain was closer to the Beijing-1 strain than to the SA14 and JaOArS982 strains. However, only on comparison of the E sequence, which neutralization, hemagglutination-inhibition and complement fixation antigenic determinants are located, between Ling and other JEV strains demonstrated that nucleotide sequence homology varied from 97.1% to 99.3% and amino acid homology from 98.6% to 99.2%. The Ling strain JEV is more closely related to the Beijing-1 strain than to the Nakayama NIH, SA14 and JaOArS982 strains in that order. Based on this analysis, the Taiwanese JEV strain appears to be more closely related to the Chinese strain than to the Japanese strain. Also, JEV strains isolated in humans are more closely related to each other than to JEV strains of mosquito isolates.

Amino Acid Sequence↗

PubMed1993

Changing seroepidemiology of hepatitis A virus infection between two regions in Taiwan differing in socioeconomic status.

In Taiwan, hepatitis A virus (HAV) infection is hyperendemic, and prior to the late 1970s more than 85% of the population was infected by 15 years of age. In this study, the prevalence of HAV infection in two regions of Taiwan with differing standards of living is evaluated. Serum antibody to HAV (anti-HAV) was determined by enzyme immunoassay. A total of 4,218 subjects under the age of 16 years were enrolled. The first group of 1,581 subjects were residents of the prosperous western plain region where the socioeconomic status and living environment have improved greatly in the past 20 years; the second group of 2,637 subjects were aborigines inhabiting the eastern and central mountain regions where improvement in the standard of living lags far behind the western region. All serum samples were collected in 1991 except for 1,100 samples collected in 1989 from elementary and junior middle school students in Tainan city. The prevalence of HAV infection was 11.9% for the western region and 81.0% for the eastern and central regions. In the eastern and central regions, 80% of the subjects had been infected with HAV before the age of six years, in contrast to 0% in the western region. By the age of 13 years, only 6% of the subjects were infected in the western region; however 97% had been infected in the eastern and central regions. Among children under the age of 10 years, only 10.6% (10/94) of the IgM-anti-HAV positive cases had clinical symptoms. These findings indicate that HAV infection has a close relationship with socioeconomic status and environmental sanitation.

Adolescent↗