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Biomedical subjects

S Antic

Publications and source records attributed to S Antic.

8 recordsLinked to original sources
PubMed2006

Lymphocyte ecto-5'-nucleotidase in obese type 2 diabetic patients treated with gliclazide.

OBJECTIVE: Lymphocyte 5'-nucleotidase is sensitive to superoxide anion, and is an indicator of oxidative stress in humans. The aim of this study was to assess the effect of the sulfonylurea drugs gliclazide and glibenclamide on lymphocyte ecto-5'-nucleotidase of type 2 diabetic patients. METHODS: Thirty obese type 2 diabetic patients were treated for three months after randomisation either with gliclazide or glibenclamide. Basic laboratory parameters (glycaemia, fructosamine, C-peptide), plasma malondialdehyde levels (MDA) as well as lymphocyte 5'-nucleotidase activity were determined, for all patients and 16 healthy controls, before and after the treatment. RESULTS: 5'-nucleotidase activity in diabetic patients before treatment with gliclazide was 1.61 +/- 0.16 nmol/min/10(6) lymphocytes, and was significantly (P < 0.01) increased compared with the level in healthy controls. After three months of gliclazide treatment, ecto-5'-nucleotidase activity fell significantly by 47.39% and 36% in unstimulated Con A- and PMA-stimulated lymphocytes, respectively. Glibenclamide treatment had no effect on ecto-5'-nucleo-tidase of type 2 diabetic patients. Glycoregulation was improved, as plasma fructosamine decreased from 53.4 to 42.1 and from 50.5 to 43.4 U/g proteins after gliclazide and glibenclamide treatment, respectively. Plasma MDA levels markedly decreased after gliclazide but not glibenclamide treatment. CONCLUSION: These results show that gliclazide treatment inhibits the activity of lymphocyte ecto-5'-nucleotidase and presumably de-creases the concentration of adenosine at the cell surface. A decrease in 5'-nucleotidase activity and attenuation of adenosine production may be a factor in the protection of tissue injury in type 2 diabetic patients.

5'-Nucleotidase↗
PubMed2006

Salvage rectal surgery--overview.

Recurrence of the disease represents the major problem in patients who undergo "curative" resection for rectal cancer, with published rate ranging from 3 to 50%. Most relapses occur within first two years of follow-up. Depending on the site of the recurrence, it can be local or distant. It also can be solitary or diffuse. In terms of potential surgical cure the best results are achieved with solitary, localized metastases. The most common sites of the solitary metastases are pelvis, liver and lung, with a fairly even distribution among these three sites. Other sites of the localized metastases can be peritoneum, lymph nodes, brain, bone, abdominal wall, ureter and kidney. These sites are less common, but not so amenable to resection. Local recurrence varies depending on the original type of surgery. It can be stated that surgical technique directly influences local recurrence rate in patients with rectal cancer. According to the results from a number of different authors 5-year survival rate after reresection is 2-13% of all patients with locally recurrent cancer, both alone and associated with distant metastases. The most important moment in this problem is to decide when not to operate. The absolute contraindications for salvage surgery are: "frozen pelvis", aneuploid tumors and those with mucinous component, clinical or CT evidence of invasion of the pelvic nerves, lymphatics or veins, or ureter bilaterally. Also, evidence of involvement of the lateral pelvic sidewalls and/or upper sacral marrow, and/or S2 is an absolute contraindication for surgery. Thus, main goals of this type of surgery are respectively: palliation of symptoms, a good quality of life and, if possible, cure with low treatment-related complication rates.

Humans↗
PubMed2004

First thousand rectal cancer cases--local recurrence and survival.

In the period 1990 - 2002, 1674 patients with colorectal carcinoma were operated in the First Surgical Clinic, Third Department for Colorectal Surgery. In 1264 cases (75.5%) rectal carcinoma was the indication for surgical treatment. Sphincter saving procedures (SSP) were performed in 824 (65.2%), abdominoperineal resections (APR) in 340 (26.9%) and resections of rectum with definitive stoma (Hartmann procedure) in 100 (7.9%) patients. We analyzed 1095 cases where curative SSP or APR were performed. All cases where curative resection was not possible because of liver metastases or inability to excise all macroscopic disease were excluded. In the group of patients where SSP was performed (767 cases), there were 26.6% high colorectal anastomoses (8cm from anal verge), 65.4% with low (4-8cm from anal verge) and 8.0% with intersphincteric coloanal anastomosis (cm from anal verge). Patohistological exam showed 5.3% Dukes A, 53.1% Dukes B, 36.5% Dukes C and 4.9% Dukes D. In the APR group (328 cases) there were 1.,5% Dukes A, 32.4% Dukes B, 62.1% Dukes C and 3.5% Dukes D. In this study we analyzed local recurrence and five-year survival in both groups. Recurrence of the disease was registered in 325 (29.6%) out of 1095 patients. Local recurrence was found in 81 (7.,4%) patients. In the SSP group recurrence occured in 215 (28.0%) out of 767 curative resections. Local recurrence alone was found in 53 patients (6.9%). SSP group was also divided into two subgroups; in the first group TME was performed and in second transection of mesorectum was carried out. Analyzing local recurrence in these two groups, in the TME group it was 7.6% and in the transection group 5.6%. In the APR group recurrence was registered in 110 (33.5%) out of 328 patients while local recurrence alone was found in 28 (8.5%) cases. Analyzing mortality we found that 234 (21.4%) out of 1095 patients died during follow-up. In the SSP group 154 out of 767 patients (20.1%) died. In the TME group mortality was 21.7% and in the transection group 16.9%. Mortality in the APR group showed that 80 out of 328 (24.4%) patients died during follow-up. Analysis by the Kaplan-Meier's test shows cumulative survival of 0.69 for all cases. In the SSP group cumulative survival is 0.72 and in the APR group 0.64 with statistically significant difference (p .001). In the TME group cumulative survival is 0.75 and in the transection group 0.,72 with statistically significant difference (p .05). We believe that performing SSP should be encouraged whenever it is possible because there is no difference in local recurrence rates and survival compared to APR. Transection of mesorectum can safely be performed in most cases with tumors located more than 8 cm form anal verge. We believe that exact preoperative staging and preoperative radiotherapy could improve results.

Adolescent↗
PubMed2000

Functional profile of the giant metacerebral neuron of Helix aspersa: temporal and spatial dynamics of electrical activity in situ.

1. Understanding the biophysical properties of single neurons and how they process information is fundamental to understanding how the brain works. However, action potential initiation and the preceding integration of the synaptic signals in neuronal processes of individual cells are complex and difficult to understand in the absence of detailed, spatially resolved measurements. Multi-site optical recording with voltage-sensitive dyes from individual neurons in situ was used to provide these kinds of measurements. We analysed in detail the pattern of initiation and propagation of spikes evoked synaptically in an identified snail (Helix aspersa) neuron in situ. 2. Two main spike trigger zones were identified. The trigger zones were activated selectively by different sets of synaptic inputs which also produced different spike propagation patterns. 3. Synaptically evoked action potentials did not always invade all parts of the neuron. The conduction of the axonal spike was regularly blocked at particular locations on neuronal processes. 4. The propagating spikes in some axonal branches consistently reversed direction at certain branch points, a phenomenon known as reflection. 5. These experimental results, when linked to a computer model, could allow a new level of analysis of the electrical structure of single neurons.

Action Potentials↗
PubMed2000

Imaging membrane potential with voltage-sensitive dyes.

Membrane potential can be measured optically using a variety of molecular probes. These measurements can be useful in studying function at the level of an individual cell, for determining how groups of neurons generate a behavior, and for studying the correlated behavior of populations of neurons. Examples of the three kinds of measurements are presented. The signals obtained from these measurements are generally small. Methodological considerations necessary to optimize the resulting signal-to-noise ratio are discussed.

Animals↗
PubMed1999

Fast optical recordings of membrane potential changes from dendrites of pyramidal neurons.

Understanding the biophysical properties of single neurons and how they process information is fundamental to understanding how the brain works. A technique that would allow recording of temporal and spatial dynamics of electrical activity in neuronal processes with adequate resolution would facilitate further research. Here, we report on the application of optical recording of membrane potential transients at many sites on neuronal processes of vertebrate neurons in brain slices using intracellular voltage-sensitive dyes. We obtained evidence that 1) loading the neurons with voltage-sensitive dye using patch electrodes is possible without contamination of the extracellular environment; 2) brain slices do not show any autofluorescence at the excitation/emission wavelengths used; 3) pharmacological effects of the dye were completely reversible; 4) the level of photodynamic damage already allows meaningful measurements and could be reduced further; 5) the sensitivity of the dye was comparable to that reported for invertebrate neurons; 6) the dye spread approximately 500 micron into distal processes within 2 h incubation period. This distance should increase with longer incubation; 7) the optically recorded action potential signals from basolateral dendrites (that are difficult or impossible to approach by patch electrodes) and apical dendrites show that both direct soma stimulation and synaptic stimulation triggered action potentials that originated near the soma. The spikes backpropagated into both basolateral dendrites and apical processes; the propagation was somewhat faster in the apical dendrites.

Action Potentials↗