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Biomedical subjects

S K Saxena

Publications and source records attributed to S K Saxena.

At least 55 records · Page 3Linked to original sources
PubMed1990

The effect of intestinal resection and urogastrone on intestinal regeneration.

Intestinal regeneration in patched intestinal defects is enhanced by both intestinal resection and urogastrone. Our aim was to determine if these two stimuli have synergistic effects. Ileal defects were patched with colon serosa in 45 rabbits. Group 1 (n = 11) were control subjects; group 2 (n = 12) underwent 50% intestinal resection; group 3 (n = 11) received urogastrone (1.5 micrograms/kg per hour subcutaneously); and group 4 (n = 11) underwent intestinal resection and received urogastrone. Animals were killed at 7 and 14 days. Intestinal resection had the greater effect on epithelialization. Urogastrone inhibited contraction and intestinal resection did not. Both intestinal resection and urogastrone increased proliferative activity. Combining intestinal resection and urogastrone did not have a synergistic effect on epithelialization and diminished the effect of urogastrone on proliferation and contraction. These findings suggest that intestinal resection and urogastrone stimulate epithelialization via similar mechanisms and that urogastrone would not enhance regeneration during intestinal adaptation.

Animals↗
PubMed1990

Histopathological changes following anterior chemotherapy in advanced breast cancer.

Twenty five patients of advanced breast cancer (Stage IIIb and IV) were studied and the histological changes following chemotherapy were looked. All the tumours showed varying degree of histological changes. Twenty eight percent tumours showed Grade I changes, 28 percent had Grade II changes and 28 percent had Grade III changes. Residual tumour was present in all the cases. The tumour showing higher grade of cancer cell degeneration following chemotherapy had better response. Seven tumours showing Grade III changes had 85.7 percent partial response. No complete response was achieved.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Shiga toxin, Shiga-like toxin II variant, and ricin are all single-site RNA N-glycosidases of 28 S RNA when microinjected into Xenopus oocytes.

Ricin, Shiga toxin, and Shiga-like toxin II (SLT-II, Vero toxin 2) exhibit an RNA N-glycosidase activity which specifically removes a single base near the 3' end of 28 S rRNA in isolated rat liver ribosomes and deproteinized 28 S rRNA (Endo Y., Mitsui, K., Motizuki, M., & Tsurugi, K. (1987) J. Biol. Chem. 262, 5908-5912; Endo Y. & Tsurugi, K. (1987) J. Biol. Chem. 262, 8128-8130, Endo, Y., Tsurugi, K., Yutsudo, T., Takeda, Y., Ogasawara, K. & Igarashi, K. (1988) Eur. J. Biochem. 171, 45-50). These workers identified the single base removed, A-4324, by examining a 28 S rRNA degradation product which was generated by contaminating ribonucleases associated with the ribosomes. To determine whether this N-glycosidase activity applies in living cells, we microinjected ricin into Xenopus oocytes. We also microinjected Shiga toxin and a variant of Shiga-like toxin II (SLT-IIv). All three toxins specifically removed A-3732, located 378 nucleotides from the 3' end of 28 S rRNA. This base is analogous to the site observed in rat 28 S rRNA for ricin, Shiga toxin, and SLT-II. Purified, glycosylated, ricin A chain contains this RNA N-glycosidase activity in oocytes. We also demonstrated that the nonglycosylated A subunit of recombinant ricin exhibits this RNA N-glycosidase activity when injected into Xenopus oocytes. Ricin, Shiga toxin, and SLT-IIv also caused a rapid decline in oocyte protein synthesis for nonsecretory proteins.

Animals↗
PubMed1989

Effect of eflorithine on intestinal regeneration.

Patching intestinal defects with adjacent serosal surfaces results in the growth of new intestinal mucosa. Since polyamine biosynthesis is associated with cellular growth and differentiation, it may be important in this regenerative process. Our aim was to determine the effect of eflorithine (difluoromethylornithine), a specific inhibitor of polyamine synthesis, on intestinal regeneration. Forty-eight New Zealand white rabbits had 2 x 5-cm ileal defects patched with adjacent cecal serosal surface. One half of the animals took 2% eflorithine in drinking water postoperatively. Six animals in each group were killed 7, 14, 21, and 28 days after patching. There was no significant difference in neomucosal growth at any time. Villous height, disaccharidase activity, and crypt cell production were significantly lower in the eflorithine-treated animals. Eflorithine-treated animals had significantly lower ornithine decarboxylase activity and polyamine levels. Despite the inhibitory effect of eflorithine on polyamine synthesis and proliferative activity, epithelialization and contraction of the patched defect were not affected. These findings suggest that polyamine synthesis is important in proliferation and differentiation of cells in the neomucosa but does not influence cell migration in intestinal regeneration.

Animals↗
PubMed1989

Effect of the duration of infusion of urogastrone on intestinal regeneration in rabbits.

Urogastrone (UG) increases the rate of mucosal regeneration on patched intestinal defects. Our aim was to determine the effect of the duration of UG administration on regeneration of serosa patched ileal defects in rabbits. Group I (n = 18) were controls. Group II (n = 15), Group III (n = 10) and Group IV (n = 5) received UG 1.5 micrograms/kg/h subcutaneously for 7 days, 14 days or 21 days respectively. Animals were sacrificed at 7 day intervals up to 21 days after patching. Neomucosal growth was significantly greater in the animals receiving UG and was greatest in Group IV. Group II and III animals had less contraction of the patched defect and greater neomucosal surface area than Group I animals at each interval but had a lesser effect than animals receiving UG continuously. Crypt cell production rate was significantly greater in UG treated animals at 7 and 14 days but fell to control levels at 21 days. Prolonging the duration of UG infusion increased the quantity of neomucosa produced by intestinal regeneration. However, UG stimulation of mucosal cell migration and proliferation occurred transiently within 14 days after patching.

Analysis of Variance↗
PubMed1989

The effect of the route of delivery of urogastrone on intestinal regeneration.

Urogastrone (UG) administered subcutaneously increases the rate of intestinal regeneration (neomucosal growth) on patched intestinal defects. Our purpose was to determine the optimal route of delivery of UG for intestinal regeneration. In 22 New Zealand white rabbits (2.1 to 3.4 kg) 2 X 5 cm ileal defects were patched with adjacent cecal serosal surface. Group I (n = 6) served as controls. Group II (n = 5), group III (n = 6), and group IV (n = 5) received UG, 1.5 micrograms/kg/hr, intravenously, subcutaneously, and intraluminally via miniosmotic pumps. Neomucosal growth was assessed 7 days after patching. Serum UG levels were detectable in only the intravenous group. Coverage of the patched defect and neomucosal area was significantly greater and contraction of the defect less in the groups receiving UG (p less than 0.05). Neomucosal area was highest in the intravenous group (286 +/- 16 mm2), intermediate in groups III and IV (236 +/- 19 and 215 +/- 20 mm2), and lowest in the control group (152 +/- 17 mm2; p less than 0.05). Sucrase and maltase activities were significantly higher in the intravenous group. Crypt cell production rate and ornithine decarboxylase activity were greater in the UG-treated animals. UG stimulated intestinal regeneration by all routes of delivery. The intravenous route had the greatest effect and was associated with the highest serum levels of UG. These findings have implications for the mechanism of the trophic effect of UG on the intestinal epithelium.

Amine Oxidase (Copper-Containing)↗
PubMed1989

Viggo phlebitis.

Explore the source record for details and available documents.

Catheters, Indwelling↗
PubMed1988

Alpha-sarcin causes a specific cut in 28 S rRNA when microinjected into Xenopus oocytes.

The toxin alpha-sarcin specifically cuts 28 S rRNA at a single position 393 nucleotides from its 3' end in isolated rat liver polysomes, provided the ribosomes are pretreated with EDTA or puromycin (Endo, Y. & Wool, I. G. (1982) J. Biol. Chem. 257, 9054-9060). In addition, alpha-sarcin behaves as a purine-specific RNase on deproteinized RNA, cleaving on the 3' side of purines in both single- and double-stranded RNA (Endo, Y., Huber, P. W., and Wool, I. G. (1983) J. Biol. Chem. 258, 2662-2667). Since alpha-sarcin does not readily enter tissue culture cells, we have injected it into Xenopus oocytes in order to determine whether the toxin cleaves after all purines or if it specifically makes a single cut in 28 S rRNA in intact cells. We report here that in oocytes alpha-sarcin specifically cuts 28 S rRNA 377 nucleotides from its 3' end, even when used at concentrations that would degrade deproteinized RNA. alpha-Sarcin does not behave as a general nuclease when injected into Xenopus oocytes nor does it operate by another means such as initiating proteolytic digestion of endogenous oocyte proteins. We demonstrate that injected alpha-sarcin causes a rapid decline in oocyte protein synthesis for soluble cytoplasmic proteins, similar in effect to injection of cycloheximide or puromycin.

Animals↗
PubMed1988

Prevention of contraction of patched intestinal defects.

Neomucosal growth on a serosal patch might increase intestinal surface area in the short-bowel syndrome but is limited by contraction of the patched defect. Our aim was to reduce contraction by mechanical or pharmacologic means. Ileal defects (2 x 5 cm) were patched with colon serosa in 14 rabbits. Group 1 (n = 5) had a plastic splint sutured to the defect edge. Group 2 (n = 4) received hydrocortisone acetate and vitamin A. Group 3 (n = 5) was the control group. Four weeks after patching there was significantly less contraction in groups 1 and 2 compared with group 3 (72.3% +/- 5.6% and 50.0% +/- 5.8% vs 31.9% +/- 1.8% initial defect size). Epithelial coverage of the defect was greater in groups 1 and 3 than in group 2. Disaccharidase activity of neomucosa and surrounding mucosa was significantly decreased in the steroid-treated rabbits. Contraction of a serosal patch can be reduced by mechanical and pharmacologic measures that may enhance the clinical applicability of this technique.

Animals↗
PubMed1988

Difluoromethylornithine inhibits urogastrone stimulation of neomucosal growth.

Urogastrone (UG) stimulates the growth of intestinal neomucosa on patched intestinal defects. This effect may be dependent on increased polyamine biosynthesis. The aim of this study was to determine if difluoromethylornithine (DFMO), a specific inhibitor of polyamine synthesis, would inhibit urogastrone stimulation of neomucosal growth. Twenty-four New Zealand white rabbits (2.1-2.9 kg) had 2 x 5-cm ileal defects patched with adjacent cecal serosal surface. Group I (n = 6) served as controls. Group II (n = 6) received UG 1.5 micrograms/kg/hr subcutaneously. Group III (n = 6) took 2% DFMO orally. Group IV (n = 6) received the same doses of UG and DFMO simultaneously. Animals were sacrificed 7 days after patching to assess neomucosal growth. Urogastrone infusion resulted in significantly greater neomucosal coverage (54 +/- 4%) and neomucosal surface area (236 +/- 18 mm2) in the Group II animals. Neomucosal coverage and contraction of the intestinal defects and neomucosal surface area were similar in the other three groups. Crypt cell production rate (15.5 +/- 2.0 cells/hr) and disaccharidase activity were also significantly greater in Group II than in the other groups. DFMO alone (Group III) resulted in a significantly lower ornithine decarboxylase (ODC) activity, polyamine content, and crypt cell production rate. Group IV animals had lower ODC activity but not lower polyamine content or crypt cell production rate. UG resulted in a significant increase in neomucosal growth. DFMO prevented this stimulatory effect and inhibited ornithine decarboxylase activity. The stimulation of neomucosal growth by UG is dependent, at least in part, on increased polyamine biosynthesis.

Animals↗
PubMed1988

Intestinal glucose uptake is increased in aged mice.

Carbohydrate metabolism is impaired in the aged. Whether this is related to impaired glucose uptake or to other factors remains unclear. We measured changes in proliferative activity, glucose uptake, and disaccharidase activity in the intestinal mucosa of mice aged 2, 12, 24, and 30+ months to evaluate glucose absorption and its relationship to intestinal structure and proliferative activity. In vitro glucose uptake was increased significantly in the 30+ month-old mice compared to the younger animals. Similarly, crypt cell production rate and thymidine uptake were also increased. However, there were no significant changes in intestinal weight and length and villus height and crypt depth. These findings suggest that altered carbohydrate absorption in the aged is related to factors other than diminished mucosal glucose uptake. Whether this increased function is related to structural changes in the gut remains unclear.

Aging↗
PubMed1988

Movement of carbofuran (nematicide) in soil columns.

Adsorption and movement of carbofuran (a systemic nematicide) were studied using two Indian soils (clay loam and silt loam) of alluvial origin. Equilibrium adsorption coefficient (K) values measured using a batch-slurry technique follows the order clay loam greater than silt loam soil. The distribution coefficients (Kd) for both the soils in batch adsorption as well as in columns were also calculated. Carbofuran movement in soil columns during water infiltration in both air-dried and water-saturated columns was estimated. The order was as anticipated from K and Kd values. A larger amount of water was needed for leaching the carbofuran to 152 cm in clay loam soil than in silt loam soil. Carbofuran appears to increase in drier soils and in finer textured soils.

Carbofuran↗
PubMed1988

Effect of urogastrone on intestinal regeneration is dose-dependent.

Urogastrone (UG) increases the rate of intestinal regeneration in intestinal defects patched with adjacent serosal surfaces by increasing the rate of epithelial cell migration and proliferation. It also inhibits contraction of the patched intestinal defect. The purpose of this study was to determine the effect of the dose of UG on these processes. Twenty male New Zealand white rabbits (1.9-2.9 kg) had 2 x 5 cm ileal defects patched with adjacent caecal serosal surface. Group I (n = 6) served as the control group. Group II (n = 5), Group III (n = 5) and Group IV (n = 4) received UG 0.15, 1.5 and 4.5 micrograms/kg/h i.v. via mini-osmotic pumps. Seven days after patching, both epithelialization of the patched defect and neomucosal surface area were significantly increased by UG and the increases were dose-dependent. Contraction was not inhibited by the lowest dose of UG but was diminished by 1.5 micrograms/kg/h. Proliferative activity in both neomucosa and adjacent normal mucosa were increased in UG-treated animals with the greatest increase in rabbits receiving 1.5 and 4.5 micrograms/kg/h UG. The effect of UG on both epithelialization and contraction of patched intestinal defects is dose-dependent. Since the lowest dose of urogastrone increased epithelialization without increasing proliferative activity, stimulated cell migration appears to be the earliest effect of UG.

Animals↗
PubMed1988

A comparative study of pterion formation and its variations in the skulls of Nigerians and Indians.

An attempt has been made to study and compare the incidence and variations in the pterion formation in the skulls of 40 Nigerians and 72 Indians obtained from the Department of Anatomy, University of Jos, Nigeria. The present study concludes: 1. All the three varieties of pterion i.e. sphenoparietal, frontotemporal and stellate are found in both races. 2. The frequency of sphenoparietal pterion is high in both races (Indians 95.3%, Nigerians 84.79%) while the frontotemporal (Indians 3.46%, Nigerians 10.11%) and the stellate (Indians 1.38%, Nigerians 5.06%) pterion are more common in Nigerians. 3. The frequency of epipteric bone is high in Indians (Indians 11.79%, Nigerians 3.79%) and is more commonly associated with sphenoparietal pterion. 4. No epipteric bone is associated with stellate pterion in both races. 5. The difference in the distance of pterion from the zygomatic arch is highly significant between two races on both sides. 6. The difference in the distance of pterion from the frontozygomatic suture is insignificant between the two races. 7. The frequency of "high Pterion" is more in Nigerians on both sides. 8. The frequency of "Backward Pterion" is more in Indians on the right side, whereas little more in Nigerians on the left side.

Adult↗
PubMed1987

Stimulation of neomucosal growth by systemic urogastrone.

Patching small intestinal defects with colon serosa results in the growth of functional neomucosa. However, the rate of neomucosal growth is slow and the defect contracts markedly. The aim of this study was to determine if systemic urogastrone would enhance neomucosal growth. Twenty-two New Zealand white rabbits had two 2 X 5-cm ileal defects patched with colon serosa and osmotic pumps placed subcutaneously. Eleven animals had saline infused at a rate of 5 microliter/hr. The other eleven rabbits had urogastrone (1 mg/ml saline) infused at the same rate. One animal died in this group. There was a modest increase in neomucosal growth after 2 weeks of urogastrone infusion. Three weeks after patching, defect coverage was significantly greater in the urogastrone group (99.8 +/- 0.1 vs 96.0 +/- 1.2%, P less than 0.005) and more defects were completely covered by neomucosa (6/10 vs 1/12, P less than 0.05). Less contraction occurred in the urogastrone group (46 +/- 2 vs 35 +/- 3% initial defect, P less than 0.005) and resultant neomucosal surface area was greater (361 +/- 12 vs 266 +/- 20 mm2, P less than 0.0005). In vitro glucose uptake was significantly greater in the urogastrone group but disaccharidase and diamine oxidase activity were similar. Crypt cell production rate was significantly greater 2 weeks after operation compared to 3 weeks in both groups and was greater in the urogastrone group compared to the saline group at 2 weeks (24.9 +/- 1.1 vs 20.1 +/- 1.1, P less than 0.02). Systemic urogastrone enhances neomucosal growth by increasing the rate of growth and diminishing contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Amine Oxidase (Copper-Containing)↗