Biomedical subjects

J J Kim

Publications and source records attributed to J J Kim.

At least 19 recordsLinked to original sources

PubMed2006

Birth of viable female dogs produced by somatic cell nuclear transfer.

Since the only viable cloned offspring born in dogs was a male, the purpose of the present study was to produce female puppies by somatic cell nuclear transfer (SCNT). Adult ear fibroblasts from a 2-month-old female Afghan hound were isolated and used as donor cells. In vivo-matured canine oocytes surgically collected (approximately 72h after ovulation) from the oviducts of 23 donors were used for SCNT. After removal of the cumulus cells, oocytes were enucleated, microinjected, fused with a donor cell, and activated. A total of 167 reconstructed SCNT embryos were surgically transferred (Day 0) into the oviducts of 12 recipient bitches (average 13.9 embryos/recipient, range 6-22) with spontaneous, synchronous estrous cycles. Three pregnancies were detected by ultrasonography on Day 23, maintained to term, and three healthy female puppies (520, 460, and 520g), were delivered by Caesarean section on Day 60. These puppies were phenotypically and genotypically identical to the cell donor. In conclusion, we have provided the first demonstration that female dogs can be produced by nuclear transfer of ear fibroblasts into enucleated canine oocytes.

Animals↗

PubMed2006

Complete regression of established subcutaneous B16 murine melanoma tumors after delivery of an HIV-1 Vpr-expressing plasmid by in vivo electroporation.

Novel therapies and delivery methods directed against malignancies such as melanoma, and particularly metastatic melanoma, are needed. The HIV-1 accessory protein Vpr (viral protein R) has previously been demonstrated to induce G2 cell cycle arrest as well as in vitro growth inhibition/killing of a number of tumor cells by apoptosis. In vivo electroporation has been utilized as an effective delivery method for pharmacologic agents and DNA plasmids that express "therapeutic" proteins and has been targeted to various tissues, including malignant tumors. For the study reported here, we hypothesized that intratumoral delivery of a Vpr expression plasmid through in vivo electroporation would induce apoptosis and growth attenuation or regression of melanoma tumors. Established subcutaneous B16.F10 melanoma tumors were injected intratumorally with a Vpr-expressing (either 25 or 100 microg) plasmid, followed by electroporation, on day 0 (i.e., when tumors had attained an appropriate size) and day 4. Treatment with 25 or 100 microg of the Vpr-expressing plasmid resulted in complete tumor regression with long-term survival in 14.3 and 7.1% of the mice, respectively. In addition, electroporative delivery of the Vpr-expressing plasmid was shown to induce apoptosis in tumors after intratumoral injection. This is the first report demonstrating the ability of Vpr, when delivered as a DNA expression plasmid with in vivo electroporation, to attenuate melanoma lesion growth and induce complete tumor regression coupled with long-term survival of mice in a highly aggressive and metastatic solid tumor model.

Animals↗

PubMed2006

Non-surgical management of microperforation induced by EMR of the stomach.

BACKGROUND: Perforation and bleeding are major complications associated with gastric endoscopic mucosal resection. Evident perforation during endoscopic mucosal resection can be managed by endoscopic clipping. However, management of microperforation is not well established. PATIENT AND METHOD: From January 2002 to June 2004, 109 early gastric cancers and 300 adenomas were treated with endoscopic mucosal resection. Iatrogenic perforations occurred in 4.16% (n=17) patients. Following exclusion of four evident perforations, microperforation was observed in 3.18% (n=13) patients. The clinical features of microperforation in patients were retrospectively reviewed. RESULTS: In a total of 13 microperforation cases, 2 patients were managed surgically. The remaining patients successfully recovered without surgical management. In the case of 11 patients without surgery, 7 experienced abdominal pain, which required analgesics, 2 patients experienced mild discomfort and 2 patients experienced no symptoms. A body temperature above 37.5 degrees C was observed in 9.1% (n=1) patients and leucocytosis above 9000 microL-1 was in 72.7% (n=8) patients. The mean duration of nasogastric tube drainage was 2.36+/-1.03 days, of fasting 4.18+/-1.17 days, of intravenous antibiotics 5.55+/-1.44 days and of hospitalisation 7.45+/-1.04 days. CONCLUSION: Microperforation induced by gastric endoscopic mucosal resection can be managed successfully using a non-surgical approach including fasting, nasogastric tube drainage and intravenous antibiotics.

Abdominal Pain↗

PubMed2006

Promoter methylation of helicase-like transcription factor is associated with the early stages of gastric cancer with family history.

BACKGROUND: To investigate the clinicopathological significance of promoter methylation of the helicase-like transcription factor (HLTF) in primary gastric cancer. PATIENTS AND METHODS: Two-hundred fifty six patients participated in this study. Methylation status of HLTF gene was evaluated in fresh-frozen tissues by the methylation-specific polymerase chain reaction. All statistical analyses were two-sided, with a 5% type I error rate. RESULTS: Aberrant methylation of HLTF was found in 98 (38%) of 256 gastric cancer patients. HLTF methylation was significantly associated with a family history in the early stages of gastric cancer, regardless of histologic types. In intestinal-type cases, HLTF methylation occurred in 15 (56%) of 27 patients with family histories, and in 26 (31%) of 85 patients without family histories (P = 0.02). In diffuse-type cases, patients with family histories were also found to exhibit a higher prevalence of HLTF methylation than those without family histories (61% vs. 34%; P = 0.009). HLTF methylation in both of the histologic types occurred in about 70-90% of the early stage cases in which the patient had a family history and in 15-30% of cases in which the patient did not have a family history. In our multivariate logistic regression analysis, the stage 1-2 cases with family histories were determined to carry a higher risk of HLTF methylation than did the stage 3-4 cases without family histories in both the intestinal-type (OR = 6.01, 95% CI = 1.20-30.01, P = 0.02) and the diffuse-type cancers (OR = 8.25, 95% CI = 1.67-40.86, P = 0.009). CONCLUSIONS: These results suggest that HLTF methylation may play a crucial role in the early stages of gastric carcinogenesis in patients with family histories and may be a valuable susceptible marker for the risk of gastric cancer in individuals with family histories.

Aged↗

PubMed2006

Nonsurgical treatment of abdominal or pelvic abscess in consecutive patients with Crohn's disease.

BACKGROUND: There is little agreement about the efficacy of nonsurgical treatment for abscess associated with Crohn's disease. Furthermore, there is no study on characteristics of abscess or patient that nonsurgical treatment could be worth trying as initial treatment. AIMS: To evaluate the outcome of nonsurgical treatment in Crohn's disease-related abscess and identify factor leading to failure of nonsurgical treatment of this complication. PATIENTS: Twenty-four patients, who consecutively admitted for Crohn's disease-related abscess to our institution during a 7-year period, underwent nonsurgical treatment as initial therapy. METHODS: Outcome data such as recurrence and intractability, and clinical features were retrospectively analysed. Univariate analysis with patient-related factors and abscess-related factors was performed for risk factor identification. RESULTS: Median follow-up period was 47.5 months. Of the eligible patients, 19 patients were treated medically and 5 patients underwent percutaneous catheter drainage with medical treatment. Overall success rate of nonsurgical treatment in our centre was 66.7%. The cumulative recurrence rate at 7 months was 12.5%. All recurrences occurred within 7 months from complete resolution on follow-up imaging. Univariate analysis showed that the significant factors which lead to failure of nonsurgical treatment were presence of associated fistula and concurrent steroid use (P=0.019 and P=0.019, respectively). CONCLUSION: Nonsurgical treatment can be considered as initial treatment modality for the Crohn's disease-related abscess without concurrent steroid therapy or relevant fistula.

Abdominal Abscess↗

PubMed2006

Identification of trait loci affecting white meat percentage and other growth and carcass traits in commercial broiler chickens.

White meat is the most economically valuable part of a broiler chicken. Increasing white meat relative to overall body size (white meat percentage, WM%) makes a broiler, gram for gram, a more valuable animal. However, accurately measuring WM% requires removing the bird from the breeding flock. Identification of markers for genomic regions associated with WM% would allow direct genetic selection on breeders. The objective of the current study was to identify genomic regions affecting WM% and other growth and carcass traits in an F2 cross between 2 commercial broiler lines that differed in WM%. Two commercial lines were crossed to generate 5 F1 half-sib families of each reciprocal cross type. One male from each family was crossed with 3 females from each of the other families within each reciprocal cross type. Seven F2 half-sib families, totaling 430 F2 individuals, were analyzed. Microsatellite markers (n = 73) on the 11 largest chromosomes were analyzed for associations with various growth and carcass traits by least squares interval mapping using line-cross, half-sib, combined, and parent of origin models. Sixty-eight QTL were identified at the 5% chromosome-wise level, including 6 QTL affecting WM%. Ten QTL reached 5% genome-wise significance, including 1 WM% QTL on Gga 2. The current study identified genomic regions harboring QTL affecting WM% and other carcass and growth traits, which may be useful for direct genetic selection, and also identified putative imprinted QTL in the chicken. The advantage of using multiple statistical models was evident because QTL were identified with the combined and parent of origin models that were not identified with the line-cross or half-sib models.

Animals↗

PubMed2006

Association of melanocortin 4 receptor (MC4R) and high mobility group AT-hook 1 (HMGA1) polymorphisms with pig growth and fat deposition traits.

The aim of this study was to analyse the combined effect of melanocortin 4 receptor (MC4R) and high mobility group AT-hook 1 (HMGA1) polymorphisms on growth and fatness traits in Duroc pigs. No significant interaction was observed between MC4R and HMGA1 for back-fat traits. An additive mode of inheritance of both gene effects was found for average daily gain and lean meat content. Maximum mean differences from combined genotypic effects were over 2 mm for back fat, 70 g/day for average daily gain and 2% for lean meat content. Therefore, utilization of polymorphisms in both MC4R and HMGA1 for marker-assisted selection could result in an economic benefit to the pig industry.

Animals↗

PubMed2006

Enteroendocrine cell counts correlate with visceral hypersensitivity in patients with diarrhoea-predominant irritable bowel syndrome.

The objective of this study was to determine whether or not the number of enteroendocrine cells (ECs) in the gut is related to visceral hypersensitivity in patients with diarrhoea-predominant irritable bowel syndrome (D-IBS). Twenty-five subjects with D-IBS (mean, 43.1 years; 16 women, nine men) were recruited into our study, along with 13 healthy controls (mean, 40.7 years; nine women, four men). Maximally tolerable pressures were evaluated via barostat testing, and the levels of ECs were immunohistochemically identified and quantified via image analysis. The numbers of ECs between the D-IBS subjects and the controls were not significantly different in the terminal ileum, ascending colon and rectum. However, the maximally tolerable pressures determined in the D-IBS subjects were significantly lower than those of the control subjects (P < 0.01), and we detected a significant relationship between the maximally tolerable pressures and the numbers of ECs in the rectum (r = -0.37, P < 0.01). Rectal sensitivity was enhanced to a greater degree in D-IBS patients exhibiting an elevated level of rectal ECs. This study provides some evidence to suggest that ECs play an important role in visceral hypersensitivity.

Adult↗

PubMed2006

Properties of cholesterol-reduced butter made with beta-cyclodextrin and added evening primrose oil and phytosterols.

The present study was carried out to examine changes in the chemical and sensory properties of butter in which the cholesterol was reduced and to which evening primrose oil (EPO) and phytosterols were added. Crosslinked beta-cyclodextrin (beta-CD) made from adipic acid was used, and approximately 90% of the cholesterol was removed. The color measurement values "L" and "a" were significantly different between the control (butter with no beta-CD treatment and no added EPO and phytosterols) and treatment A (butter treated with 10% crosslinked beta-CD); however, the color values for "L" and "a" were similar. The color value "b" in treatment B (butter treated with 10% crosslinked beta-CD and 5% phytosterols and 3% EPO added) was significantly higher than in the other treatments. The thiobarbituric acid value of treatment B was significantly higher than that of the control and treatment A. Scores for hardness, elasticity, and cohesiveness were significantly lower in the control than in treatment A. Differences in sensory characteristics did not result from the beta-CD treatment but from the addition of EPO and phytosterols. In microscopic examinations, no noticeable differences were found among the treatments, and a smooth texture and a fine, uniform crystalline structure were observed. Results indicated that about 90% of the cholesterol was reduced by crosslinked beta-CD and that the beta-CD treatment itself did not adversely influence the chemical and sensory properties of the butter. However, the addition of EPO and phytosterols to the butter appeared to impair its sensory properties, especially in terms of rancidity and overall acceptability.

Butter↗

PubMed2005

Psychosocial assessment by phone for high-scoring patients taking the Edinburgh Postnatal Depression Scale: communication pathways and strategies.

The well-documented risks associated with perinatal depression provide a strong argument for universal screening. However, uncertainty about what to do with findings is a significant barrier to implementing screenings where obstetric care is provided. Based on experience with a comprehensive screening program, we describe a protocol for those critical communication pathways that encourage a dynamic phone exchange between a mental health caller and the patient who has scored in the high range on the Edinburgh Postnatal Depression Scale. In addition, we present guidelines for developing an action plan for addressing intervention needs and closing the feedback loop to the original administrators of the scale.

Adult↗

PubMed2005

Role of FOXO1A in the regulation of insulin-like growth factor-binding protein-1 in human endometrial cells: interaction with progesterone receptor.

Insulin-like growth factor-binding protein-1 (IGFBP1) is a major secretory product of the decidualized endometrium. In the present study, we investigated the role of two transcription factors, progesterone receptor (PGR) and a member of the forkhead box class O family of transcription factors (FOXO1A), in the regulation of the IGFBP1 gene in endometrial cells. Human endometrial fibroblasts (HuF) expressed FOXO1A, progesterone receptor A (PGRA), and progesterone receptor B (PGRB) proteins, whereas the endometrial adenocarcinoma cell line, HEC-1B cells, expressed only FOXO1A and no detectable PGR proteins. When FOXO1A expression was silenced using small interference RNA, IGFBP1 expression decreased in both HuF and HEC-1B cells. Using the chromatin immunoprecipitation technique, we demonstrated that liganded PGR was recruited to the IGFBP1 promoter region (-358 to -49). In addition, immunoprecipitation of HuF nuclear proteins with a PGR antibody followed by immunoblotting with anti-FOXO1A revealed that these two proteins interact in these cells. Reporter studies demonstrated that whereas liganded PGRA or PGRB increased a progesterone response element-linked reporter construct, pPRE/ GRE.E1b.Luc, coexpression of FOXO1A inhibited the PGRB response in HuF and synergistically increased PGRA and PGRB response in HEC-1B cells. Furthermore, in HEC-1B cells, FOXO1A increased IGFBP1 promoter activity, and coexpression of PGRA or PGRB further increased the promoter activity in a cooperative manner. In HuF, the response to FOXO1A and PGR was not additive; in fact, it was lower than the sum of the individual responses. Thus, FOXO1A and PGR associate with one another, and each influences the transactivating potential of the other. The cell type-dependent responses strongly implicate the involvement of other cofactors.

Adenocarcinoma↗

PubMed2005

Does this patient have oesophageal motility abnormality or pathological acid reflux?

BACKGROUND AND AIMS: The diagnostic values of particular symptoms centred on oesophagus, among patients with suspected oesophageal motility abnormality or pathological acid exposure, are not yet fully understood. The aim of this study was to determine the predictive accuracy of these symptoms in diagnosis of oesophageal motility disorder or pathological acid exposure. PATIENTS AND METHODS.: A total of 462 patients who had undergone conventional oesophageal manometry and ambulatory 24-h pH monitoring to investigate a clinical suspicion of oesophageal motility disorder and pathological acid exposure were enrolled in this study. According to their principal complaints, the patients were divided into the dysphagia category, the non-cardiac chest pain category, the gastrooesophageal reflux disease-related symptom category and the extraoesophageal symptom category. RESULTS: Two hundred and two (44%) out of 462 patients yielded abnormal findings on manometry and/or pH monitoring. Dysphagia was associated with a likelihood ratio (LR) of 2.11 [95% confidence interval (CI), 1.02-4.00)] in patients exhibiting a combination of oesophageal motility abnormality and pathological acid exposure. During oesophageal manometry, the dysphagia substantially increased the likelihood of classic achalasia (LR, 6.24; 95% CI, 3.32-8.78) and diffuse oesophageal spasm (LR, 3.58; 95% CI, 1.03-7.12). When the patients with dysphagia were divided into two groups according to the severity of their symptoms, classic achalasia was significantly frequent in patients with severe dysphagia (P = 0.016). On the other hand, non-cardiac chest pain was the clinical factor that reduced the likelihood of classic achalasia (LR, 0.22; 95% CI, 0.04-0.93). The distribution of pathological acid exposure was significantly frequent between the groups of patients with and without gastrooesophageal reflux disease-related symptom (P = 0.011). CONCLUSION: A small number of oesophageal symptoms are helpful in predicting the likelihood of abnormal findings on oesophageal tests among patients with a clinical suspicion of oesophageal motility disorder and pathological acid exposure. The most useful finding is a severe dysphagia, which is likely to have classic achalasia.

Adult↗

PubMed2005

The role of follow-up endoscopy after total gastrectomy for gastric cancer.

BACKGROUND: Follow-up endoscopy after total gastrectomy for gastric cancer is commonly performed without there being any definite evidence of clinical relevance. Therefore, we investigated the role of the upper endoscopic examinations after total gastrectomy for gastric cancer. METHODS: The medical records of 212 early gastric cancer (EGC) patients and 622 advanced gastric cancer (AGC) patients who underwent follow-up endoscopic examination after total gastrectomy between 1994 and 2001 were reviewed. RESULTS: Two of 212 EGC patients and 233 of 622 AGC patients revealed tumour recurrence at all sites. All the endoscopically accessible local tumour recurrences (n=24) were found in the AGC group. Anastomosis site stenosis was detected in 72 of 834 patients. CONCLUSION: Follow-up endoscopy after total gastrectomy for gastric cancer is useful in detecting complications and tumour recurrence. However, this procedure has a limited role in the clinical management and overall survival for patients with recurrent gastric adenocarcinoma.

Adenocarcinoma↗

PubMed2004

Quantitative study of degeneration and new growth of axons and synaptic endings in the chinchilla cochlear nucleus after acoustic overstimulation.

To determine if acoustic overstimulation altered synaptic connections in the cochlear nucleus, anesthetized adult chinchillas, with one ear protected by a silicone plug, were exposed for 3 hr to a 108-dB octave-band noise, centered at 4 kHz, and allowed to survive for periods up to 32 weeks. This exposure led to cochlear damage in the unprotected ear, mainly in the basal regions of the organ of Corti. The anterior part of the ipsilateral posteroventral cochlear nucleus consistently contained a band of degenerating axons and terminals, in which electron microscopic analysis revealed substantial losses of axons and synaptic terminals with excitatory and inhibitory cytology. The losses were significant after 1 week's survival and progressed for 16-24 weeks after exposure. By 24-32 weeks, a new growth of these structures produced a resurgence in the number of axons and terminals. The net number of excitatory endings fully recovered, but the quantity with inhibitory cytology was only partially recouped. Neuronal somata lost both excitatory and inhibitory endings at first and later recovered a full complement of excitatory but not inhibitory terminals. Dendrites suffered a net loss of both excitatory and inhibitory endings. Excitatory and inhibitory terminals with unidentified postsynaptic targets in the neuropil declined, then increased in number, with excitatory terminals exhibiting a greater recovery. These findings are consistent with a loss and regrowth of synaptic endings and with a reorganization of synaptic connections that favors excitation.

Acoustic Stimulation↗

PubMed2004

Fine structure of long-term changes in the cochlear nucleus after acoustic overstimulation: chronic degeneration and new growth of synaptic endings.

The companion study showed that acoustic overstimulation of adult chinchillas, with a noise level sufficient to damage the cochlea, led to cytological changes and degeneration of synaptic endings in the cochlear nucleus within 1-16 weeks. In the present study, the same stimulus was used to study the long-term effects on the fine structure of synaptic endings in the cochlear nucleus. For periods of 6 and 8 months after a single exposure to a damaging noise level, there ensued a chronic, continuing process of neurodegeneration involving excitatory and inhibitory synaptic endings. Electron microscopic observations demonstrated freshly occurring degeneration even as late as 8 months. Degeneration was widespread in the neuropil and included the synapses on the globular bushy cell, which forms part of the main ascending auditory pathway. Neurodegeneration was accompanied by newly formed synaptic endings, which repopulated some of the sites vacated previously by axosomatic endings on globular bushy cells. Many of these synaptic endings must arise from central interneurons. The findings suggest that overstimulation can induce a self-sustaining condition of progressive neurodegeneration accompanied by a new growth of synaptic endings. Noise-induced hearing loss thus may progress as a neurodegenerative disease with the capacity for synaptic reorganization within the cochlear nucleus.

Acoustic Stimulation↗

PubMed2004

Fine structure of degeneration in the cochlear nucleus of the chinchilla after acoustic overstimulation.

To study plastic changes in the cochlear nucleus after acoustic stimulation, adult chinchillas were exposed once to a 4-kHz octave-band noise at 108 dB SPL for 3 hr. After survival times of 1, 2, 4, 8, and 16 weeks, samples were taken for electron microscopy from a part of the cochlear nucleus, where cochlear nerve fibers degenerated after the noise exposure. Progressive changes in fine structure were characterized as early, intermediate, and late stages of degeneration. Freshly occurring synaptic degeneration appeared in each period from 1-16 weeks. Endings with large round vesicles, putative excitatory synapses of the cochlear nerve, displayed progressive increases in neurofilaments and enlarged synaptic vesicles. Compared to controls, synaptic vesicles seemed fewer, often in small clusters in the interior of endings, and smaller in the synaptic zone. These early changes progressed to mitochondrial disintegration and overt "watery" degeneration. Some surviving endings, however, were shrunken and displaced partially by enlarged spaces in the synaptic complex. Dense-cored vesicles gathered in these endings. In terminals with pleomorphic and flattened vesicles, presumed inhibitory endings, cytological changes appeared within 1 week and persisted for months. The synaptic endings darkened, some vesicles disintegrated, and many smaller flatter vesicles collapsed into heaps. Especially at the presynaptic membrane, vesicles were shriveled, but a few mitochondria were preserved. Without overt signs of synaptic degeneration, some of these cytological changes presumably reflect reduced synaptic activity in the inhibitory endings. These changes may contribute to a continuing process associated with abnormal auditory functions, including hyperacusis and tinnitus.

Acoustic Stimulation↗

PubMed2004

Uterine receptivity and implantation: the regulation and action of insulin-like growth factor binding protein-1 (IGFBP-1), HOXA10 and forkhead transcription factor-1 (FOXO-1) in the baboon endometrium.

In primates, the phase of the menstrual cycle when the uterus becomes receptive is initially dependent on estrogen and progesterone. Further morphological and biochemical changes are induced as a result of biochemical signals between the embryo and the maternal endometrium. Blastocyst implantation in the baboon usually occurs between 8 and 10 days post ovulation and is similar to that described for the rhesus macaque. In the baboon, when chorionic gonadotropin is infused in a manner that mimics blastocyst transit, this has physiological effects on the three major cell types in the uterine endometrium. The luminal epithelium undergoes endoreplication and distinct epithelial plaques are evident. The glandular epithelium responds by inducing transcriptional and post-translational modifications in the major secretory product, glycodelin. The stromal fibroblasts initiate their differentiation process into a decidual phenotype and are characterized by the expression of actin filaments. Decidualization, is the major change that occurs in the primate endometrium after conception. During this process the fibroblast-like stromal cells change morphologically into polygonal cells and express specific decidual proteins. Studies in the baboon demonstrated that insulin-like growth factor binding protein-1 (IGFBP-1) gene expression is a conceptus-mediated response. Subsequent studies in vitro established that IGFBP-1 is transcriptionally regulated by FOXO1 and HOXA10 which together upregulate the IGFBP-1 promoter activity. A baboon endometriosis model was utilized to determine if the changes observed during uterine receptivity in normally cycling animals were compromised. The data suggests that in animals with disease, markers of uterine receptivity are not appropriately expressed in the eutopic endometrium. It is possible that these differences influence the fertility of the animals with disease and the baboon could be used as a primate model to study the causes of infertility as a result of endometriosis.

Animals↗

PubMed2004

Seasonal factors controlling mineral precipitation in the acid mine drainage at Donghae coal mine, Korea.

Monitoring over a 12 month period in the Sanae creek flow in acid mine drainage, Donghae coal mine area, demonstrates that the concentrations of dissolved metals and sulphate are highest during autumn when water flow in the creek is at its lowest. The highest pH values of the stream were measured in April and May, whereas the lowest pH was recorded in October. The Fe concentration of stream water rapidly decreased downstream due to the precipitation of Fe oxyhydroxide and/or oxyhydroxysulfate phases in the stream. Mineral precipitates in the creek in the Donghae mine area show various colours such as brownish yellow (Munsell colour 9.5 YR hues), reddish brown (Munsell colour 3.5 YR hues) and white depending on seasons and distance from the pollution source in the creek. Such phenomena are attributed to the variation in pH and chemical composition of stream water caused by seasonal factors. The measured pH ranges in stream water of the brownish yellow, white and reddish brown precipitates are pH 3.2-4.5, 4.5-6.0 and 5.3-6.9, respectively.

Journal Article↗