Birsen Kaplan

Relationships between tensile strength, ascorbic acid, hydroxyproline, and zinc levels of rabbit full-thickness incision wound healing.

PurposeThis work was carried out to follow up the healing of full-thickness incision wounds opened on the back skin of rabbits in order to gain insight into the periodical correlation among such factors as ascorbic acid, collagen (hydroxyproline), the zinc content, and tensile strength of wound tissue. The need to provide vitamin C or zinc supplements after such wound incisions is also discussed.MethodsFull-thickness incision wounds and the ascorbic acid and hydroxyproline levels were measured in 24 rabbits by spectrophotometric methods on day 0 and on the 3rd, 5th, 7th, and 15th days after operation. The tensile strength was measured by a polygraph using a force displacement transducer. The zinc levels of the wounds were measured by atomic absorption spectrophotometry.ResultsThe zinc and hydroxyproline levels reached the peak levels on the 5th day, but the tensile strength of wound increased sharply on the 7th day after wounding while the zinc levels did not change. These results indicated that in the first 7 days of wound healing, high levels of ascorbic acid, hydroxyproline, and zinc cumulation occurred in the wound tissue, and the tensile strength reached its highest level on the 15th day without any supplementation.ConclusionThe supplementation of zinc and/or ascorbic acid should therefore be given just at the beginning of the wounding period, especially if there is deficiency of these nutrients.

Effects of taurine in glucose and taurine administration

Summary.Taurine has several biological processes such as hypoglycemic action, antioxidation, detoxification, etc. To assess the effect of taurine administration on the guinea pigs with hyperglycemia, blood glucose, C-peptide levels together with morphologic alterations in the pancreatic ultrastructure were investigated in terms of hypoglycemic action and malondialdehyde and total sulfhydryl group levels with regard to oxidation-antioxidation relation. Animals were divided into four groups of six. Glucose supplementation group was administrated a single dose of glucose (400 mg/kg, i.p.) injection. Glucose and taurine supplementation group was administrated glucose treatment (a single dose, 400 mg/kg, i.p.) following taurine (a single dose, 200 mg/kg, i.p.). Taurine and glucose supplementation group was administered taurine treatment (a single dose, 200 mg/kg, i.p.) following glucose treatment (a single dose, 400 mg/kg, i.p.). Control animals received no treatment. Blood samples were collected at the end of the experiments for the determination of glucose, C-peptide (indicator of insulin secretion), lipid peroxidation (thiobarbituric acid reactive substances), and total sulfhydryl groups levels. Pancreatic tissue samples were then collected and processed for transmission electron microscopy. The findings showed that glucose supplementation following taurine administration significantly decreased blood glucose level by increasing C-peptide level and the pancreatic secretion stimulated morphologically and insignificantly changed thiobarbituric acid reactive substances and total sulfhydryl group levels. These observations suggest that taurine administration may be useful in hyperglycemia because of its hypoglycemic and protective effects.

Effect of EGF on the corneal wound healing of alloxan diabetic mice

We identified the local treatment effect of epidermal growth factor on corneal wound healing of alloxan diabetic mice. The corneal wounds were induced by 0.5 M NaOH solution on the corneal surfaces of the diabetic and non-diabetic groups. The local epidermal growth factor solution (100 ng ml-1) was dropped in 5-microliters aliquots into the eye twice a day. The corneal wounds were measured daily for 15 days and examined histologically at the end of 15th day of experimental period. The results indicated that topical epidermal growth factor treatment of diabetic and non-diabetic mice greatly improved the incidence of healing of wounded corneas.

The effects of taurine on perfused heart muscle malondialdehyde levels

1. Taurine is found as a free amino acid in plasma and many tissues such as heart, muscle, brain and blood. Its exact role is not fully defined but it appears to have an important effect on the function of the heart. 2. The purpose of this study was to investigate the effects of taurine (10(-3) M and 10(-2) M) on malondialdehyde levels in perfused heart muscle. 3. In this study we found that administrated taurine before anoxia and reperfusion increased the malondialdehyde levels but administrated taurine after anoxia decreased the malondialdehyde levels in perfused heart muscle compared to the taurine administrated group before anoxia. 4. Anoxia did not change the perfused heart muscle malondialdehyde levels.

Effects of epidermal growth factor in artificial tear on vitamin C levels of corneal wounded eye tissues

Purpose To investigate the effect of artificial tear (AT) solution and epidermal growth factor (EGF) treatment on the cornea and aqueous humour ascorbic acid (AA) levels of full-thickness corneal wounded eyes.Methods The effect of EGF on the AA levels of aqueous humour and corneal wound tissue was determined in full-thickness corneal wounded rabbit eyes on the seventh postoperative day. There were three groups: untreated controls, AT-treated controls and an EGF+AT-treated experimental group (n = 6 in each group). Corneal wounded eyes were topically treated with 5 µl AT or 5 µl EGF in AT (1 mg/1 EGF in AT prepaaration which contained 3.0% carbopol 940) twice daily for 6 days after operation. The wound strengths were also measured on the seventh postoperative day as a measure of wound healing. Statistical analysis was carried out using the Mann-Whitney U-test by Statview program.Results The wound strengths of corneas, and AA levels of wound tissues and aqueous humour, increased significantly following AT and EGF treatment (p < 0.05).Conclusion In the corneal wounded eye, aqueous humour serves as a source of vitamin C and there may be a relation between EGF treatment in AT and AA levels of corneal wounded eye tissues.

Effects of limited food intake and vitamin C supplementation on pancreatic glucagon and insulin in guinea pigs.

The aim of this study was to investigate the effects of limited food intake (LFI) (24, 48 and 120 h) and a single i.p. dose of vitamin C supplementation (500 mg/kg) on serum glucose and C-peptide levels, and pancreatic insulin and glucagon levels in guinea pigs. The highest serum glucose levels were found after vitamin C supplementation plus LFI for 48 h (LFI 48). Serum C-peptide levels were not significantly affected by food limitation (LFI 24, LFI 48, or LFI 120) as compared with controls, but when vitamin C was supplemented, the C-peptide levels were moderately enhanced. Immunohistochemical findings on pancreatic islets showed increased staining intensity for both insulin and glucagon when vitamin C was supplemented. In addition, the alpha and beta cells were stimulated, particularly by vitamin C supplementation plus LFI 120. Based on these findings, vitamin C supplementation may have a beneficial effect on the alpha and beta cells.

The effect of taurine administration on vitamin C levels of several tissues in mice

Summary.Taurine (2-aminoethane sulphonic acid), a sulphur-containing beta amino acid, is the most prevalent free intracellular amino acid in many human and animal tissues. Vitamin C metabolism is also fluenced by sulphur-containing amino acids. The aim of this study is to investigate the effect of taurine administration on the vitamin C levels of plasma and several tissues (brain, liver, kidneys) in mice with incisional skin wounds. Animals were divided into two as control and taurine groups. Taurine was freshly dissolved in sterile saline and administered daily (60 µl, ip) for five days in the taurine group. At the end of the fifth day, the animals were killed by decapitation. The brain, liver and kidneys were immediately removed. Vitamin C levels were measured in plasma and several tissues. The administration of taurine had no effect on the plasma vitamin C levels (P>0.05) but significantly increased in liver and kidneys (P<0.001). In conclusion, taurine may affect the vitamin C metabolism in tissues by different mechanisms.

Effects of vitamin C supplementation on plasma antioxidant status in unfed periods.

In this study, the antioxidant protection of ascorbic acid (AA) supplementation during different unfed periods (24, 48, 120 h) was determined with blood lipid peroxidation level (thiobarbituric acid reactive substances, TBARS) and compared with plasma antioxidant sulfydryl group (RSH) content. Weight loss was induced by increasing the unfed period together with vitamin C supplementation. Blood AA levels decreased by starvation but increased by vitamin C supplementation. RSH content in plasma also decreased with the unfed period; these decreases became apparent by vitamin C supplementation. TBARS formation increased significantly by AA supplementation in the 120-h starvation period.