Comparison of Different Doses of Clonidine as an Additive to Intrathecal Isobaric Levobupivacaine in Patients Undergoing Infraumbilical Surgeries.

BACKGROUND: Spinal anesthesia is a safe, reliable, and inexpensive technique with the advantage of providing surgical anesthesia and prolonged postoperative pain relief, and it also blunts autonomic, somatic, and endocrine responses to surgical stimulus. AIM: The aim of this study was to assess the efficacy 15 µg and 30 µg of intrathecal clonidine along with 3 mL of 0.5% isobaric levobupivacaine in comparison with plain 0.5% isobaric levobupivacaine. SETTING AND DESIGN: The prospective, interventional, randomized, comparative, double-blinded study was conducted after obtaining approval from the institutional ethical committee. MATERIALS AND METHODS: Seventy-five patients posted for elective lower-limb orthopedic surgeries were randomly divided into three groups with 25 patients in each group as L (levobupivacaine 0.5%), LC-15 (levobupivacaine 0.5% + clonidine 15 µg), and LC-30 (levobupivacaine 0.5% + clonidine 30 µg). All the patients were given spinal anesthesia using the study drugs, and various parameters were monitored. STATISTICAL ANALYSIS: The three groups were compared statistically using analysis of variance and Student's t-test (independent samples t-test). P < 0.05 was considered statistically significant. RESULTS: There was a statistically significant difference among the three groups with respect to the onset of time for maximum sensory blockade and duration of analgesia. A statistically significant difference was noted among the three groups with respect to the onset of time for maximum motor blockade. CONCLUSION: Both doses of clonidine produced prolonged sensory block compared to the control. It has been found that 30 µg of clonidine as an adjuvant has produced faster onset and prolonged duration sensory block compared to 15 µg of clonidine.

Vitamin D-3 intestinal absorption in vivo: influence of fatty acids, bile salts, and perfusate pH on absorption.

Intestinal absorption of vitamin D-3 in physiological concentrations was studied in the live unanesthetised rat. In both the jejunum and the ileum a linear relationship was found between the absorption rate of the vitamin and its intraluminal concentration. Increasing the sodium taurocholate concentation in the perfusate above 5mM did not change ileal absorption rate but did decrease jejunal absorption rate. The vitamin's rate of absorption was raised by increases in either the hydrogen ion concentration in vivo is mediated by passive diffusion. The rate of absorption of ttion or the perfusate's flow rate. Addition of 2.5 mM fatty acids of varying chain length and degrees of saturation resulted in a decrease in the rate of vitamin D-3 absorption. These experiments indicate that vitamin D-3 absorption in vivo is mediated by passive diffusion. The rate of absorption of the vitamin is influenced by the composition of the perfusate and the thickness of the unstirred layer.

Intestinal absorption of alpha-tocopherol in the unanesthetized rat. The influence of luminal constituents on the absorptive process.

3H-alpha-tocopherol intestinal absorption was studied in the unanesthetized rat. The rate of alpha-tocopherol absorption remained linear over a wide range of concentrations (4 nM to 400 micrometer). Increasing the sodium taurocholate concentration in the micellar infusate up to 15 mM did not increase the rate of absorption of the vitamin. Addition of long-chain fatty acids to the micellar infusate decreased the absorption rate of the vitamin (p less than 0.05). The decrease was most significant (p less than 0.01) following the addition of the polyunsaturated linolenic (C18:3) acid. Increasing the hydrogen ion concentration in the perfusate increased the absorption rate of alpha-tocopherol. The present experiments in vivo support the conclusions drawn from in vitro uptake experiments which indicated that alpha-tocopherol is absorbed by a passive diffusion process. These experiments indicate that micellar expansion with polyunsaturated fatty acids interferes with the absorption of alpha-tocopherol and may result in deficiency of the vitamin.

Vitamin A1 intestinal absorption in vivo: influence of luminal factors on transport.

Intestinal absorption of [3H]retinol was studied in the unanesthetized rat. Luminal perfusate was recirculated through isolated intestinal segments with intact vascular and lymphatic circulation. Apparent saturation kinetics were found in physiological concentrations of retinol, whereas a linear relationship between the concentration and absorption rate was found at pharmacological concentrations of retinol in the perfusate. In physiological concentrations, retinol uptake in vitro by everted gut sacs was unaffected by anoxia or metabolic inhibitors and uncouplers. In vivo retinol absorption rate was decreased when sodium taurocholate concentration was raised above 5 mM, or when 2.5 mM linoleic or linolenic acids were added to the perfusate. Absorption increased markedly as the thickness of the unstirred water layer was diminished. Variations in perfusate pH from 4.5 to 8.6 did not change the retinol absorption rate. In vivo absorption of retinol in physiological concentrations is mediated by a saturable, carrier-mediated passive absorption mechanism modified by the presence of fatty acids of varying chain length.

Vitamin K1 intestinal absorption in vivo: influence of luminal contents on transport.

Intestinal absorption of [3H]phylloquinone was investigated in the unanesthetized rat by the use of a technique of recirculating perfused isolated intestinal segments. Apparent saturation kinetics were found as the concentration of the vitamin in the perfusate was increased in a stepwise fashion from 15 nM to 300 muM. Alkalinization of the perfusate or the addition of 2.5 mM linoleic acid to the perfusate caused a significant (P less than 0.05) decrease in the absorption rate of phylloquinone. Modifications in the perfusate concentration of sodium taurocholate, the substitution of a nonionic detergent (Pluronic F-68) for sodium taurocholate, the addition of medium- and long-chain saturated fatty acids, or the addition of vitamins K2 and K3 to the perfusate did not alter the absorption rate of the vitamin. Decreasing the thickness of the unstirred water layer by increasing the perfusion rate caused a significant increase in phylloquinone absorption rate. In vivo absorption of vitamin K1 appears to be mediated by an energy requiring saturable transport mechanism. The composition of the perfusate, its pH, and its rate of flow are all important determinants of vitamin K1 absorption rate.

Effect of Feeding Lactobacilli on the Coliform and Lactobacillus Flora of Intestinal Tissue and Feces from Piglets 1.

Development of fecal Lactobacillus and coliform in healthy newborn pigs during the first 48 h after birth was studied. Lactobacilli were detected (104 per g) in the feces of newborn pigs as early as 4 h after birth and colifroms by 8 h (105 per g). By 24 h the two types were present in near equal numbers (104 to 105/g). A frozen concentrate of a human isolate of Lactobacillus lactis was fed to piglet litters (8 to 10 animals per litter) from the time of their birth. Bottle feeding resulted in reduced fecal coliforms in nursing pigs but lactobacilli were not increased in number. After 54 days of treatment, the Lactobacillus to coliform ratio (L/C) was 1280:1; in control pigs not fed lactobacilli, the ratio was 2: 1. A continued suppression of coliforms was observed for 30 days after treatment was discontinued. The influence of Lactobacillus on the bacterial flora of the gastrointestinal tract was studied. With scouring pigs, enteropathogenic Escherichia coli (EEC) were present in larger numbers in tissue homogenates of the tract than in the lumen. The virulence of the EEC found prosent was confirmed by experimental infection in pigs. In control, nonscouring pigs only non-EEC were isolated from tissue sections. In Lactobacillus -fed pigs, E. coli was reduced to low numbers; also, the few E. coli observed were non-enteropathogenic. There were higher numbers of lactobacilli in tissue sections of Lactobacillus -fed pigs than in control and scouring pigs. The lactobacilli isolated from tissue homogenates of the treated animals resembled biochemically and serologically (fluorescent antibody staining) the Lactobacillus which was fed. Histological studies were done to observe the bacteria in frozen sections of washed intestine obtained from Lactobacillus -fed pigs; staining revealed large numbers of gram-positive bacilli. On the other hand, control pigs which died of scouring revealed many coliform types present. Pigs in groups receiving colostrum and lactobacilli did well; no evidence of diarrhea was seen and many lactobacilli were observed in tissue throughout the small intestine. Even after the challenge with EEC serotype 09:K:NM, these two groups of pigs did not show any signs of disease and few coliform types (cocco-bacillary forms) were observed. Pigs not receiving colostrum but only lactobacilli did not scour before challenge and many lactobacilli were present in tissue from the small intestine. However, 72 h after challenge these latter animals revealed symptons of diarrhea and coliforms were seen in the small intestine tissue in addition to lactobacilli.

Colonic absorption of bacterially synthesized vitamin K2 in the rat.

Colonic absorption of bacterially synthesized vitamin K2 ([3H]menaquinone-9) was studied with everted rat colonic sacs in vitro. The mean +/- SE rate of absorption of the vitamin by the colon was 20 +/- 1.45 pmol/min per 100 mg tissue at 300 nM mucosal concentration of the vitamin. The rate of absorption did not change (P greater than 0.10) with the addition of 2,4-dinitrophenol, Na azide, or KCN to the mucosal incubation medium. No evidence for transmural transport of the vitamin was detectable. When the concentration of the vitamin was increased in a stepwise fashion up to 900 nM, the absorption rate remained linear with respect to the mucosal fluid concentration (r = 0.98). Autoradiography indicated that the vitamin accumulated in the mucosal and submucosal layers of the large bowel. Absorption of the vitamin by the large bowel takes place via a passive, nonsaturable process that shows no evidence of energy dependence or carrier mediation. It was concluded that vitamin K2 (bacterial origin) is absorbable by the rat colon in amounts sufficient to meet the daily requirement of the animal and may explain the lack of bleeding problems in the face of episodic lack of dietary vitamin K.

Mechanism and site of small intestinal absorption of alpha-tocopherol in the rat.

The site and mechanism of alpha-[5-methyl-3-H]tocopherol absorption was investigated using everted rat small bowel sacs incubated in a micellar medium. Mean plus or minus SE absorption rates of the vitamin at 300 muM incubation solution concentration by proximal, medial, and distal small bowel segments were 2.2 plus or minus 0.17, 3.4 plus or minus 0.21, and 2.0 plus or minus 0.04 nmoles per min per 100 mg, respectively. Addition of 2,4-dinitrophenol, sodium azide, or potassium cyanide to the incubation medium in separate experiments did not change the rate of absorption (P greater than 0.10). Stepwise increase in incubation solution tocopherol concentration up to 1200 muM resulted in a linear increase in the absorption rate. In all of the above described experiments the rate of absorption of the vitamin by the medial portion of the small bowel was significantly (P smaller than 0.01) higher than the rate of absorption of the vitamin by the proximal and distal small bowel segments. No transmural transport of the vitamin into the serosal compartment took place. Autoradiographic examination of the tissue after incubation disclosed accumulation of the vitamin in the submucosal lymphatic spaces. Alpha-Tocopherol absorption by the rat small bowel appears to be a passive diffusion process taking place at the highest rate in the medial portion of the small bowel.