KOWSAR MEDICAL JOURNAL
Year:2001 | Volume:5 | Issue:4|Papers Count:14

As the population ages, the elder’s ability to lead life to its fullest potential will decrease. Inactivity as well as risk taking behaviors results in balance dysfunction and falls. Alteration in environmental conditions such as support surface and lighting cause balance instability. The purpose of this study was to determine how conflicting visual and ankle proprioceptory inputs influence balance in elderly with a history of falls. 62 elders (female) aging between 65 and 92 years old and 30 female adults between 18 and 30 years of age participated in the project. Elderly subjects with two or more falls in the six month prior to study were assigned to the faller group (N=29), whereas those with no history of falling during the same time were assigned to a non-faller group (n=33). Subjects were evaluated using a sensory organisation test (Foam and Dome). ANOVA was used to evaluate the scores. The results indicated that sway increases with age. Subjects in the faller group showed a significant increase of sway compared to non-fallers. Orientation inputs from the ankle appear to have greater importance for preventing falls compared with visual references.

There is marked elevation of endogenous opioid levels in plasma of human subjects with biliary cirrhosis as well as animal model of cholestasis. In addition, development of morphine tolerance and dependence has been shown to be inhibited by drugs which reduce brain serotonin levels. However, i.c.v. injection of serotonin increases the morphine analgesia. In the persent study we have investigated the role of serotonergic pathway in determining the withdrawal syndrome in mice model of cholestasis. There were three experimental groups: unoperated mice, sham operated mice and mice in which the main bile duct was ligated. Physical dependency was assessed by precipitating a withdrawal syndrome by naloxone (2 mg/kg) five days after induction of cholestasis. Acute and chronic administration of serotonin receptor antagonists, cyproheptadine (5 mg/kg), methysergide (3 mg/kg) and tropisetrone (10 mg/kg) attenuated withdrawal and decreased the antinociception. However, acute treatment by fluoxetine (15 mg/kg), an inhibitor of serotonin uptake, increased the withdrawal signs and antinociception, and chronic administration of fluoxetine during five days after induction of cholestasis decreased the naloxone precipitated withdrawal syndrome and antinociception. These experiments lead us to conclude that the naloxone-precipitated withdrawal signs which occur in mouse model of cholestasis, are potentially dependent on serotonergic pathway.

Since the discovery of radioadaptive response in 1984, a worldwide effort has being carried out to clarify the basic mechanism of this phenomenon. Substantive evidence show that when human, animal and plant cells are exposed to low doses of an agent that induce DNA damages, they often become less sensitive to the detrimental effects of higher doses of those agents administered subsequently. This phenomenon has been termed an adaptive response. There is growing evidence for the existence of radioadaptive response. On the other hand, some investigators have reported entirely negative results in individuals with chromosome instabilities as well as healthy persons. Additionally, there are reports indicating that low-level pre-irradiation of human lymphocytes can be problematical; for example in radiotherapy, the induction of radioadaptive response in cancerous cells can be a great problem. In our previous studies we observed a young healthy non-responder who showed a severe hypersensitivity to radiatin after a low dose treatment. We selected this hypersensitive donor for a follow-up study. To assess whether this kind of hypersensitivity to ionizing radiation is a temporary situation or not, we evaluated the frequency of radiation-induced chromosome aberratins during a 6 month follow-up. Peripheral blood lymphocytes of this donor were exposed to an adapting dose of 10 cGy X-rays followed by a challenge dose of 3 Gy X-rays with different radiation qualities. Our blood donor did not show adaptive response in any experiment. In this regard, considering the lack of radioadaptive response in all experiments, it may be concluded that the lack of of such a response is not a temporary situation. Despite the fact that we do not know the frequency of individuals who show such an extraordinary synergistic effect, it can be concluded that possible implications of radio adaptive response in the estimation of risks of low-level radiation exposure may be more problematical.

IgE is one of the five immunoglobulin classes in human serum, with molecular weigh about 190 kD. The range of IgE in atopic patient is at least 30-40 folds more than normal population. In addition to difficulties of purification, the expense is very high; so we attempted to use a relative simple and economic method for purification of IgE.In present study, high titer patients serum (higher than 1000 IU/ml) were collected and pooled. Serum diluted with phosphate buffer saline (PBS) and precipitated with 40% ammonium sulfate. Then, the IgE rich supernatant were precipitated with 60% ammonium sulfate. The precipitate dialysed against phosphate buffer and run on the ion exchange column. IgE rich fractions were eluted with NaCl gradient. To remove any contaminant proteins, IgE rich fractions were run on affinity column with sepharose 4B anti-IgE antibody. The absorbed IgE was eluted with changing of buffer. Finally, the purified IgE approved with SDS-PAGE and immunobloting methods.

The development of secondary palate is one the most important issue in embryology. On the 16th day of gestation in rats, palatal shelves (P.S.) are fused. In order to study the development process of palate, 30 embryos cases were used on the 16th day at the interval of the two hours. The cases were fixed in solution of formal saline and embeded in paraffin. Then, serial sections with 5 mm thickness were prepared and stained by Haematoxylin and Eosin, periodic acid-shiff (P.A.S.) with diastase, toluidine blue and periodicacid-silver nitrate . The results are as follows: 1. The elevation of P.S. started anteriorly and progressed posterioly, while these precesses were not necessarily simultanous, and in addition each of these P.S. can be independently elevated . 2. The chronological age cannot be regarded as a consistent criterion to predict the stages of development palate. 3. The closure of P.S. begins from the middle area and progresses anteriorly and posterioly until the soft palate is closed down. The most anterior area closed last. 4. The thickness of the epithlia P.S. in the anterior area is more than that of the middle and posterior ones. 5. Muco-polysaccharides cannot be the cause of the elevation of the P.S.; however they have an effective role in fusion of The P.S.6. Glycogen had no effect in the elevation of P.S., but it may have some role in fusion of the P.S.

Tectorial membrane is a kind of extracellular matrix which contains glycoconjugates. These components are important in hearing. Glycoconjugates are also responsible for many developmental phenomena. Disorders in formation of such components, are also responsible for some kinds of congenital inner ear malformation. In this project, rat embryos from 12th to 20th day of gestation and rat infants from the first to 15th of pastnatal day were used. We used histochemical methods such as Alcina blue, P.A.S., Toluidin blue and lectins (BSA1-B4, P.N.A. and sialidase digestion/PNA) to recognize glycoconjugates. The results indicated that Galactose/N-acetylgalactosamine appeared in tectorial membrane after postnatal days. Galactos existed in tectorial membrane from the begining during embryonic period but decreased gradually after birth. The changes in hyaluronic acid were also observed during development. We observed that some changes in glycoconjugates and morphological proccesses are coincident. It seems that the changes in glycoconjugates are developmentally regulated.

The ionic currents show nonlinear behaviour and electrical stimuli can influence their activation and inactivation kinetic. The time constant of depolarizing or hyperpolarizing current pulses has an impotant role in the firing behaviour of neurones. In present study, the effect of two forms of depolarizing command potential with different time constant of hyperpolarizing phase were investigated on calcium currents of F1 neurone somata in Helix aspersa. In both protocols, the F1 neurone clamped from holding potentials of -90 or -40 mV to +90 mV. In standard ringer, the quasitrapezoidal command potentials in compared with rectangular command potentials caused not only a 9% increase in peak of total inward currents but also it shifts the voltage of inward current threshold and peak current toward negative potentials. In Na+-K+ free solution, the quasitrapezoidal command potentials in compared with rectangular command potentials caused a 36% decrement in peak of Ca2+ currents and shift its threshold voltage toward positive potentials. After application of nifedipine, while the quasitrapezoidal command potentials caused the threshold voltage of nifedipine-resistance Ca2+ currents became more positive but it caused no considerable change in peak of current. The results show that the slowly hyperpolarization of membrane potential through the quasitrapezoidal command potentials can influence kinetics of ionic channels.

In the present study Excretory Secretory Antigens (ESA) of toxoplasma gondii were evaluated in immunization of 8-10 week inbred female Balb/c mice. Tachyzoites of the parasite were cultured in cell-free incubation medium (RPMI-1640), then supernatant of the medium was loaded in ion exchange chromatography column. Two fractions (ESA-F1 and ESA-F2) were collected from the column. For immunization of the mice, 50 mice were allocated into 5 groups, each group 10 mice. The first, second, third and the fourth group were immunized, 2 times with total-ESA, ESA-F1, ESA-F2 or toxoplasma lysate antigen (TLA) respectively. The fifth group was selected as negative control group (non-immunized). The virulent RH strain of toxoplasma gondii was used for challenging. The results indicated that Total-ESA, ESA-F1 and ESA-F2 in the immunized mice resulted in a delayed-type hypersensitivity reaction (DTH) and lymphocyte transformation responses. All non-immunized mice died within 10 days, whereas immunized mice survived for longer time (P>0.05). The highest survival rate was observed in mice that received ESA-F2. We suggest that these antigens, specially ESA-F2, should be valuable for the development of new strategies for immunization against toxoplasmosis.

Alcohol and narcotic use is one of the major causes of the driving accidents. Therefore enforcement laws are to be practiced to prevent such social and economic losses. All applicants for driving license are being tested for addiction since 1996 in Iran which seems a proper pool of data to extract the incidence of regular narcotic users. In present investigation urinary test documents of 148447 applicants were studied. Their urine was first examined with Latex agglutination, if proved positive then the sample was tested by means of thin layer chromatography (TLC). Latex results indicate that 5162 samples (3.5%) were positive. TLC proved positive in 628 (0.42%) of these samples. The incidence rate among different provinces appeared to be 1.05% in Fars, 0.63% in West Ajerbijan, 0.63% in Markazi, 0.53% in Khozestan, 0.44% in Tehran, 0.39% in Kermanshah and 0.38% in Gilan. The incidence in present study seems to be 0.5% less than that in the general population, according to the official statistics. Therefore, it is concluded that the screening tests should be carried out randomly in roads all over the country, and for those especially penalized or involved in accidents.

Mustard gas is one of the harmful chemical agents which destroys tissues by alkylation. The lesions of this toxic agent cause short-and long-term effects. The long term lesion of this agent may cause mutagenic and carcinogenic effects including leukemia. Myelodysplastic syndromes (MDS) is one of the preleukemic disease that may leads to leukemia. In these syndromes morphology of peripheral blood cells including neutrophils (eg, decrease in granulation of neutrophil and increase percentage of pelgeroid neutrophil will) change. It is believed that frequency of leukemia is raised in chemical casualties and it may occurs following myelodysplastic changes. Therefore it was decided to search the long-term effect of mustard gas on morphology of peripheral blood cells. For this purpose blood samples were taken from 237 chemical casualties and 202 normal subjects and examined for complete blood count (CBC) and peripheral blood smear.In stained smears, leukocyte differential count, large granular lymphocyte (LGL), atypical lymphocyt, hand-mirror cells, G-scoring and PPP in neutrophils were specially studied. It was concluded that The average of RBC and WBC count, and also The average of different leukocytc types except lymphocyte, were higher than normal group. The average of large granular lymphocyte, atypical lymphocyte and hand-mirror cells was high and PPP had significant change against normal.According to these results, it seems that the immune system in these patients is active. In addition, both low G-Score and high PPP in neutrophils (important morphological criteria is recommended for study of MDS in the future.

Sulfur mustard is one of the chemical warfare agents. Understanding its cytopathological effect can greatly help control its further tissue damage. In this research, effects of sulfur mustard on V79 fibroblast cells in culture were studied.After monolayer formation, cells were exposed to mustard (0.05-0.9 microlit/ml) at different time intervals (10 seconds to 8 minutes), and observations were recorded. Result revealed that at low mustard concentrations and short exposure time (till 0 .3 microlit and one min.) no specific changes could be observed under light microscope, whereas at high doses and longer exposure time, some irreversible changes, like cytoplasmic and nuclear evacuation and hyaline zone formation occurs and at 0.9 mL and 8 min, cell death occur. The cell membrane is the last organelle to be damaged. It seems the cells try to preserve their integrity till last moments. Hence this system provides a good model for the study of cellular toxicity of alkylating agents and also the results can be used in medical care of mustard victims.