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Biomedical subjects

C B Chawan

Publications and source records attributed to C B Chawan.

At least 19 recordsLinked to original sources
PubMed2006

Flax seed oil and flax seed meal reduce the formation of aberrant crypt foci (ACF) in azoxymethane-induced colon cancer in Fisher 344 male rats.

Flax seed oil and flax seed meal are good sources of omega-3 fatty acids. The objective of this study was to explicate the effects of feeding flax seed oil and flax seed meal on AOM-induced aberrant crypt foci (ACF) in Fisher 344 male rats. Following an acclimatization period, rats were divided into six groups and fed AIN 93G diet Control (C), C+7 and 14% soybean oil (SBO), C+7 and 14% flax seed oil (FSO) and C+10 and 20% flax seed meal (FSM). All rats received 16 mg/kg body weight of AOM at 7 and 8 weeks of age. The rats were euthanized with CO2 at 17 weeks of age. FSM and FSO reduced the incidence of ACF which are putative precursor lesions in the development of colon cancer in the distal colon by 88% and 77%, in the proximal colon by 86% and 87% with a total reduction of 87.5% and 84%, respectively. Glutathione-S-transferase (GST) activities were significantly (P<0.05) higher in rats fed C+7 and 14% FSO and C+10 and 20% FSM, as compared to rats fed C+SBO diets. Results of this study showed that FSO and FSM reduced the incidence of AOM-induced ACF formation and may therefore be effective chemopreventive agents.

Animals↗
PubMed2006

Red palm oil suppresses the formation of azoxymethane (AOM) induced aberrant crypt foci (ACF) in Fisher 344 male rats.

Red palm oil (RPO) contains significant levels of carotenoids and Vitamin E. In this experiment we compared the inhibitory effects of RPO (7% and 14% levels) and soybean oil (7% and 14%) on azoxymethane (AOM) induced aberrant crypt foci (ACF). Thirty-two male Fisher 344 rats were randomly assigned to four groups. Two groups received AIN-93 G control (C) diet containing 7% and 14% soybean oil (SBO), respectively. Groups 3 and 4 received a treatment diet consisting of 7% and 14% RPO, respectively. The rats received subcutaneous injections of AOM at 16 mg/kg body weight at 7 and 8 weeks of age. At 17 weeks of age rats were killed by CO(2) asphyxiation. Numbers of ACF (mean+/-SE) in the proximal and distal colon were: 39.9 +/- 0.9, 53.8 +/- 2.8, 26.0 +/- 3.0, 27.5 +/- 1.5 and 118.2 +/- 1.7, 125.6 +/- 3.2, 41 +/- 7, 52.3 +/- 1.8 in rats fed 7% SBO, 14% SBO, 7% RPO and 14% RPO, respectively. The results of this study showed that RPO reduced the incidence of AOM induced ACF and may therefore have a beneficial effect in reducing the incidence of colon cancer.

Animals↗
PubMed2003

In vitro study of Listeria monocytogenes infection to murine primary and human transformed B cells.

Immunity to Listeria monocytogenes is largely mediated by T lymphocytes. Recently, B lymphocytes or their secreted products are implicated to provide immunity against L. monocytogenes infection. To understand whether L. monocytogenes can infect and kill B cells as a possible strategy to initiate an infection, we examined the effects of L. monocytogenes on a human B lymphoma (Ramos RA-1) and mouse primary B cells in vitro. L. monocytogenes infection resulted in significantly (p<or=0.05) high cytotoxicity (58-79%) for Ramos and 39-68% cytotoxicity for mouse primary B cells. In contrast, non-pathogenic L. innocua caused only 1.2% cytotoxicity for Ramos and 19% for primary B cells. Bacterial cells were found frequently adhered to the B cell surfaces; however, active invasion was not a prerequisite for infection. L. monocytogenes caused loss of B cell surface molecules, pore formations, cell swelling, membrane damages and apoptosis. This study demonstrates that L. monocytogenes can infect and kill B cells as a possible strategy to initiate a successful infection.

Animals↗
PubMed2002

Dietary inulin suppresses azoxymethane-induced preneoplastic aberrant crypt foci in mature Fisher 344 rats.

Preneoplastic aberrant crypt foci (ACF) are generally accepted as reliable markers for colon carcinogenesis in animal models. Rat model ACF studies, however, use younger rats, and there are no published reports on the suitability of adult rats for ACF studies. In this study, inulin, a known suppressor of azoxymethane (AOM)-induced ACF, was tested for its ability to suppress ACF formation in mature rats. After a 2-wk acclimation period, 12-mo-old Fisher 344 retired male breeders received two subcutaneous injections of AOM dissolved in saline at weekly intervals. In experiment 1, six groups received 0, 4, 8, 10, 12 and 16 mg AOM/kg body at each injection and were fed AIN-93M diet. In experiment 2, four groups of rats were fed 10 mg AOM/kg body at each injection based on the results of experiment 1, and were fed 0, 2.5, 5 and 10 g long-chain inulin diets/100 g. All the rats were killed after 11-wk feeding periods. In experiment 1, there was a significant (P < 0.05) AOM dose response on ACF formation. Rats fed >10 mg of AOM had greater (P < 0.05) mortality. In experiment 2, there was a significant increase in cecal weight and a decrease in cecal pH from 7.17 in the control group to 6.87, 6.61 and 5.76 in the groups fed inulin at 2.5, 5.0 and 10 g/100 g, respectively. Long-chain inulin dose-dependently reduced ACF incidence in the colon (P < 0.01). Compared with rats fed the control diet, the percentage reductions of ACF in rats fed 2.5, 5.0 and 10 g inulin diets/100 g were 25, 51, and 65, respectively. The results of this study indicate that mature rats can be used as models in ACF studies, and dietary long-chain inulin dose-dependently suppresses AOM-induced ACF formation in Fisher 344 mature male rats.

Age Factors↗
PubMed2002

Dietary inulin suppresses azoxymethane-induced aberrant crypt foci and colon tumors at the promotion stage in young Fisher 344 rats.

This study was designed to determine the effect of 10% dietary long-chain inulin on the azoxymethane (AOM)-induced colonic preneoplastic aberrant crypt foci (ACF) and small intestinal and colon tumors at the initiation (I), promotion (P) and I + P stages (20 rats per treatment) in Fisher 344 male weanling rats. After an acclimatization period of 1 wk, groups of Fisher 344 male weanling rats were assigned to consume AIN 93G diet (control) or AIN 93G diet containing 10% inulin. All the rats received 16 mg/kg body AOM dissolved in saline subcutaneously at 7 wk of age followed by a second injection at 8 wk of age. An additional group of five rats received only saline and consumed the control diet. The rats received the assigned diets until asphyxiation by CO(2) at 16 wk of age for the ACF experiment and 45 wk for the end-point tumor experiment. Feed intake, weight gain, diarrheal index, cecal weight, cecal pH, ACF and tumors in the colon were determined. Rats fed inulin had diarrhea after 2 wk of feeding and recovered by approximately 4 wk. Cecal weight was greater in rats fed inulin and cecal pH was lower. The inulin group had more than 66% fewer aberrant crypts and 60% fewer ACF compared with the control group. Tumor incidences in the small intestine and colon of rats in the control, I, P and I + P groups were: 78, 31, 0 and 11% and 90, 73, 69 and 50%, respectively. The corresponding values for the distal portion of the colon were 87, 63, 45 and 33%, respectively. Colon tumors per tumor-bearing rat were 4.2, 3.09, 1.36 and 1.2 for the control, I, P and I + P groups, respectively. All groups differed, P < 0.05. The results of this study indicate that dietary long-chain inulin suppresses AOM-induced ACF formation, an early preneoplastic marker of colon tumorigenesis in rats, and colon tumors, particularly at the promotion stage.

Age Factors↗
PubMed2002

Influence of packaging method and storage time on shear value and mechanical strength of intramuscular connective tissue of chevon.

The objectives of this study were to determine the effects of storage time (ST) and packaging method (PM) on tenderness and changes in intramuscular connective tissue (IMCT) strength of chevon. Spanish does (8 mo of age, average BW 25 kg) were harvested (n = 12), chilled at 4 degrees C for 24 h, and then fabricated into 2.5-cm-thick leg, shoulder/arm, and loin/rib cuts. The cuts from six carcasses were vacuum-packed and aged at 2 degrees C for 0, 4, 8, or 12 d. To assess the influence of a packaging method that favors oxidation on postmortem tenderization, the cuts from the remaining six carcasses were placed on styrofoam trays, overwrapped with polyvinyl-chloride film, and stored at 2 degrees C for similar periods. At each ST, longissimus (LM), semimembranosus (SM), and triceps brachii (TB) muscles were assessed for Warner-Bratzler shear (WBS) values. The WBS of uncooked meat, myofibrillar fragmentation index (MFI), and collagen solubility were assessed on LM. The IMCT samples were prepared to assess changes in mechanical strengths and for scanning electron microscopy (SEM). Intact honeycomb structures of endomysium, with no muscle fiber elements, were observable under SEM. The PM or ST did not influence the mechanical strength of IMCT preparations, as measured by a texture analyzer. Collagen solubility of LM muscles also did not change during aging. For both PM, cooked meat WBS values were higher (P < 0.01) in SM and TB than in LM. In the SM samples, the average WBS values were higher (P < 0.01) at d 0 than at other ST. Although MFI of LM increased with increasing aging time (P < 0.05), changes in WBS over ST were minimal in TB and LM samples. The WBS of uncooked LM decreased sharply up to 8 d postmortem in both PM (P < 0.05). However, there was no PM x ST interaction to indicate any adverse influence of packaging on tenderization of chevon. The results suggest that aging chevon cuts for more than 4 d may not result in significant additional improvement in tenderness.

Aging↗
PubMed1997

Bifidobacterium longum and lactulose suppress azoxymethane-induced colonic aberrant crypt foci in rats.

Bifidobacterium longum has been shown to afford protection against colon tumorigenesis. Lactulose, a keto analog of lactose, serves as a substrate for preferential growth of Bifidobacterium. It is not known whether feeding lactulose along with B. longum will have any advantage over feeding of B. longum alone. To test this combination effect, 61 male Fisher 344 weanling rats were divided into four groups of 15 rats each (16 in the control group) and assigned to one of the following four diets for 13 weeks: (i) AIN76A (control, C); (ii) C + 0.5% B. longum (C+Bl, containing 1 x 10(8) viable cells/g feed); (iii) C + 2.5% lactulose (C+L); (iv) C + 0.5% B. longum + 2.5% lactulose (C+Bl+L). All animals received a s.c. injection of azoxymethane at 16 mg/kg body wt at 7 and 8 weeks of age. Colons of 10 rats from each dietary group were analyzed for aberrant crypt foci (ACF), which are preneoplastic markers. Colonic mucosa and livers from five rats were analyzed for glutathione S-transferase (GST, a Phase II enzyme marker). Results indicate that feeding of lactulose and B. longum singly and in combination reduces the number of ACF (P = 0.0001) and the total number of aberrant crypts significantly (P = 0.0005). The total number of ACF in diets C, C+Bl, C+L and C+Bl+L were 187 +/- 9, 143 +/- 9, 145 +/- 11 and 97 +/- 11 respectively. There was no significant difference in weight gain among treatments. Colonic mucosal GST levels were significantly (P = 0.05) higher in the Bl and L groups compared with group C. Initially there was a mild diarrhea in lactulose-fed rats. There was a positive correlation between higher cecal pH and number of ACF. Results of the study indicate that Bifidobacterium and lactulose exert an additive antitumorigenic effect in rat colon.

Animal Feed↗
PubMed1983

Effect of feeding fermented milk on the incidence of chemically induced colon tumors in rats.

The effect of feeding skim milk fermented by Streptococcus thermophilus or Lactobacillus bulgaricus on the incidence of chemically induced colon tumors was studied in rats. Weanling Fisher-344 rats were fed chow plus skim milk (SM), chow plus SM fermented by S. thermophilus, chow plus SM fermented by L. bulgaricus, or chow plus water until sacrifice at 36 weeks, or before if moribund. Colon tumors were induced by s.c. injections of 1,2-dimethylhydrazine hydrochloride during weeks 3 through 22. The control (chow + water) group received saline injections. The survival rate of the rats fed fermented milks was significantly higher than that of the rats fed nonfermented milk. The latter had a significantly higher incidence of ear-duct tumors than the rats receiving fermented milk. The percentage of rats showing colon tumors was similar among all three experimental groups. The control group did not have any tumors. The rats receiving fermented milk had a significantly higher incidence of small-intestine tumors than those receiving nonfermented milk. The rats on S. thermophilus milk had the lowest percentage of malignant colon tumors of the three experimental groups. Results indicated that the feeding of fermented milks altered the metabolism of 1,2-dimethylhydrazine and shifted the target organ from the ear duct to the small intestine. In addition, the colon tumor distribution for the fermented-milk groups appeared to shift toward the anus.

Animals↗
PubMed1981

Influence of short term fasting on chicken alimentary canal mucosa.

Little is known about the physiological effects of short-term fasting in avian species. The present study was developed to examine the alimentary mucosal changes in fasted birds by scanning and transmission electron microscopy. Chickens of various ages were fasted for periods of 3, 5, and 7 days. Water was provided ad libitum. At the end of the fasting periods the birds were sacrificed along with ad libitum fed controls. Tissue samples from crop, duodenum, and ileum were processed by standard methods for scanning and transmission electron microscopy (SEM and TEM). The SEM samples were prepared by vacuum drying methods. The TEM samples were embedded in Spurrs embedding medium. Mucosal sloughing was observed in the crop and small intestine with SEM only in fasted birds. With TEM, separation was observed between the mucosal cells of fasted birds with membranous whorls in these spaces. Sloughed cells may be an endogenous protein source for the fasting bird.

Animals↗
PubMed1978

Response of broiler chickens to low level intake of polychorinated biphenyl isomers.

Commercial-type broiler starter and finisher feeds containing 0, .1, 1.0, 5.0, 10.0, or 20.0 ppm of polychlorinated biphenyl isomers (PCBs) as Aroclor 1254 (Monsanto) were fed to male broiler chicks (Arbor Acres 70 X Cobb) from hatching to 8 weeks of age. Feed intake and body weights were recorded on a weekly basis. The birds were killed at 8 weeks of age and samples of leg and breast muscle and adipose tissue were removed from each bird for PCBs analysis by gas chromatography (Pesticide Anal. Manual, FDA, '74). Linear log-log dose response curves with confidence limits were fitted to all data. There was a progressive, significant reduction in growth in response to increasing levels of PCBs fed. PCBs toxicity symptoms were seen at 10 and 20 ppm levels. All tissues showed significant, progressive accumulations of PCBs in response to increased dose.

Adipose Tissue↗
PubMed1978

Relationship between intestinal movements and pancreatic juice secretion in the domestic chicken.

The relationship between the intestinal movements and the pancreatic juice secretion in the domestic chicken was studied. The main pancreatic ducts of commercial broiler-type chickens 12 to 14 weeks of age were cannulated, and the pancreatic secretions were recorded by a drop counter. Balloon catheters for monitoring the intestinal movements were implanted in the proximal duodena in the same animals. Feeding and drinking activities were monitored by photocells. The recordings from the drop counter, the balloon catheter, and the feeding and drinking activity monitor were made in relation to the time of day. These recordings indicated that the pancreatic secretory rate correlates with the pattern of intestinal movements of the proximal duodenum in the domestic chicken. The data also suggest the movement of chyme in the duodenum under ad libitum feeding conditions to be at a steady state during the light period. During the dark period, the intestinal movements and the flow of pancreatic juice are intermittent.

Animals↗
PubMed1977

Comparison of tracheal histopathology and scanning electron microscopy of infectious laryngotracheitis.

Samples of trachea were examined with light microscope, fluorescent microscope, and scanning electron microscopy (SEM). Negative controls and infectious laryngotracheitis (ILT) positive samples were compared. Histopathology illustrated lesions characteristic fo ILT. Lesions seen with SEM suggested surface changes including ciliary disruption. luminal debris, epithelial slough, crevices, hemorrhage and exudate. Fluorescence was noted in infected tracheas throughout both trials using fluorescent antibody (FA) technique.

Animals↗
PubMed1976

Cecal mucosal response to coccidiosis in growing chickens.

The cecal mucosal changes of a subclinical coccidial (E. tenella) in chickens was studied by scanning electron microscopy. Oral inoculation was used and the mucosal surface of the ceca was studied. A control group from the same hatch of chickens was sampled simultaneously. The ceca from the infected birds was markedly smaller and contained some hemorrhagic areas. The control birds maintained a relatively smooth continuous epithelium throughout the study. During the infection, early fenestration was seen in the epithelium followed by its disruption. The crypts were easily seen as the disease progressed and in some cases the epithelium became denuded. The infective organism may inhibit replacement of degenerating epithelium.

Animals↗
PubMed1976

Infected feather follicles in cage reared broilers.

A high incidence of feather follicle infection was observed in broilers reared in cages with wood slat floors. The incidence of feather follicle infection was significantly higher for males than for females within cage-reared broilers at 59 days of age. Male broilers at 50 days of age had a significantly lower incidence of the feather follicle condition than hatch mates at 59 days of age. Intact feather follicles were removed from freshly killed cage-reared birds and prepared for scanning electron microscopy (SEM). Examination of infected follicles revealed surface detail about the lesions. Removal of the encrustations covering the infected follicles revealed numerous cocci type bacteria at the base of the follicle. Infected and non-infected follicles were also examined by conventional histological techniques. Gram positive cocci were observed at the base of the infected follicles.

Animals↗
PubMed1975

Characteristics of the absorptive surface of the small intestine of the chicken from 1 day to 14 weeks of age.

The epithelial surface of the intertine of chicks 1 day to 14 weeks of age was examined with both scanning and transmission electron microscopes. Most of the intestinal villi were seen to be plate-like structures. During the first week post-hatch, goblet cell orifices were easily seen. Goblet cell pores were not readily apparent in the older birds. During this stage of early development discontinuity was seen among some epithelial cells. The villi of birds one week or older showed a more convoluted mucosal surface than the younger birds. Areas of cell extrusion were observed at the tips of some villi. The three dimensional cylindrical structure of the microvilli was shown with the scanning electron microscope.

Age Factors↗