Showing papers by "Tehran University of Medical Sciences published in 1992"

Interaction of aminoglycoside antibiotics and lithium at the neuromuscular junctions.

Abstract: Lithium in the form of the carbonate or citrate salts has been used by Cade in 1949 for the treatment of affective disorders Lithium is known to reduce the supply of inositol, the key substrate for the phosphoinositide cascade, by inhibiting some of the enzymes which hydrolyse the inositol phosphates On the other hand aminoglycoside antibiotics are used extensively in the treatment of life-threatening infections despite their three important toxicities on kidney, ear and neuromuscular junctions It has been suggested that aminoglycoside antibiotics inhibit the signal-transduction pathway by interaction with the inositol polyphospholipids, thereby inhibiting the production of second messenger molecules In 1977 two case reports described prolonged neuromuscular blockades, one following succinylcholine and the other after pancuronium in patients receiving lithium therapy The following investigation was undertaken to determine whether lithium interferes with aminoglycoside antibiotics (gentamycin and amikacin) at the neuromuscular junctions The neuromuscular blocking effect of aminoglycoside antibiotics were tested in the isolated phrenic nerve-hemidiaphragm preparation of the rat The IC50 of gentamycin and amikacin were 175 and 527 mmoll-1 respectively Thereafter sodium chloride of the media was partially replaced by lithium chloride and the effect of gentamycin (175 mmoll-1) and amikacin (527 mmoll-1) were studied in this media Incubation of the preparation by 05, 15 and 50 mmoll-1 lithium 30 min before the use of antibiotics reduced the neuromuscular blocking effect of gentamycin and amikacin significantly It appears that the prevention of the antibiotic-induced neuromuscular blockade by lithium observed in this study may be due to the changes of release of acetylcholine at the neuromuscular junctions

Serum protein polymorphisms (HP, TF, GC and PI) in four Iranian population samples.

Abstract: SummaryA total of 960 individuals from four Iranian population samples (Tabriz, Tehran, Yazd, Mashhad) was typed for HP and for TF, GC and PI subtype polymorphism. Statistically significant intergroup heterogeneity in the distribution of allele frequencies was found only in the HP polymorphism. Comparisons with other Iranian populations suggest considerable ethnic differences with regard to the TF and GC subtye polymorphisms. Some rare alleles were observed in all four samples (Tabriz: GC*1C1; Tehran: PI*S: Yazd: PI*S; Mashhad: PI*Z).

Duration and causes of cessation of breast feeding in working mothers in Ghazvin, Iran.

Abstract: This study determines the duration and reasons for stopping breast feeding among working mothers in the city of Ghazvin near Tehran Iran in 1988. The study sample included 259 working mothers who were paramedical and nonmedical personnel had ended breast feeding and had one living child aged under 3 years. 100% of mothers had initiated breast feeding at birth. Breast feeding introduction ranged from 0 to 99 hours after delivery. 68.2% received breast milk between 7 and 24 hours after birth. The duration of breast feeding was significantly negatively correlated with the time of introduction of breast milk after delivery. The difference between the mean duration of breast feeding and the first introduction of food was statistically significant. Duration of breast feeding was significantly correlated with the age of introduction of food supplements. Duration of breast feeding was significantly negatively correlated with maternal age at first marriage at pregnancy and delivery and at last delivery. Duration of breast feeding was significantly related to insufficient supplies of milk and work outside the home.

Determination of the optimum heat stress index at a foundry

Abstract: This paper presents a case study to determine the efficiency of the currently used heat stress indices in correlation with wet bulb globe temperature (WBGT) as a permissible index at a foundry plant and to evaluate the extent of the physiological responses such as heart rate and body temperature in correlation with heat stress indices. The field consisted of a foundry plant where a shift work was in operation. The results indicated that wet globe temperature (WGT), corrected effective temperature (CET), and predicted four-hour sweat rate (P4SR) indices have the best correlation with WBGT index respectively, and P4SR and CET indices correlate well with physiological responses more successfully than WBGT does in hot-dry conditions, CET index gives the best correlation with body temperature while P4SR is the most accurate with the heart rate. MJ/RI, Vol. 6, No.1, 49-53, 1992 INTRODUCTION Volllmc6 NlImbcr I Bahar 1311 Spring 1992 The microclimate at a workplace can be classified as either hot-dry or hot-humid. The effects of such various environments on man and the strains produced differ depending on the thermal conditions. In some indus­ tries such as foundries, workers can be exposed to severe heat mostly in the form of radiation and the individuals may experience discomfort. Thus the use of indices is required to assess the thermal stress, but hygienists are experiencing considerable difficulties in the application of these indices to predict the level of heat strain resulting from exposure to stressful hot conditions··5•7 The purpose of the present study, therefore, was to make a comprehensive comparison between heat stress indices to determine the most suitable index in order to predict the tolerability of the thermally-stressful condition in the working environ­ ment and the safe values of heat s trains in relation to the optimum heat stress indices. Table I. Means and standard deviation or environmental und physiological puramelers Environmental Physiological Group WBGT CET P .. SR nSI WGT B. T'\" H. Rhlfm UT 27.57 27.84 4.40 92.24 28.32 37.27 76 5.62 4.U8 2.36 23.95 4.92 0.18 4.52 Control 21.47 23.65 0.84 88.35 23.24 37.18 7t 1.78 1.88 0.38 37.96 1.85 0.17 4.40 49 D ow nl oa de d fr om m jir i.i um s. ac .ir a t 5 :5 0 IR S T o n W ed ne sd ay D ec em be r 5t h 20 18 Determination of Optimum Heat Stress Index Table II. Regression equations for heat stress indices tested

Experience with adrenocortical tumors in children: a report of eleven cases

Abstract: During a period of IS years from 1975 to 1989, eleven children with adrenocortical tumors were managed with relatively favorable results in our center. Despite its rarity in the pediatric age group, our series is one of the largest reported in the literature in the given period of time. All of our 11 patients presented with hyperfunction of the adrenal cortex. Virilization alone was the most frequent presenting sign, occurring in eight patients. Two patients suffered from Cushing's syndrome and one patient had mixed presentation of Cushing's syndrome and virilization. There were six females and five males in the series. Four of five males presented before two years of age. Female patients presented at an older age. In nine out of 11 patients the tumor was on the right side. Mean age at presentation was 3.55 years. Serum levels of testosterone, dehydroepian­ drosterone (DHEA), and cortisol were elevated in all cases tested and apparently are superior alternatives to more traditional measurements of urinary 17ketosteroids and 17-hydroxy corticosteroids. The majority of our cases were investigated by the employment of IVP and sonography. In one patient 1131 iodocholesterol scintigraphy was used. Transabdominal approach through a transverse upper abdominal incision is recommended. In this series only one intraoperative complication was encountered. At a mean follow-up of five years, 10 out of 11 children were alive and had no evidence of tumor recurrence. In all patients pre-operative steroid replacement was essential. Con­ trary to our pathologic reports «six adenoma, three carcinoma, and two undetermined» we found favorable outcomes in the majority of our patients. We conclude that in contradiction to previous concensus, most pediatric adrenocortical tumors will behave as a benign neoplasm and that the size and weight are the only morphologic predictors of their biological behavior. MJIRI, Vol. 6, No. I, 29-34, 1992 Address reprint requests to Dr. J. Ahmadi, Head of Department of Pediatric Surgery, Children'S Medical Center Hospital, Tehran University of Medical Sciences, Tehran, Iran.

Colorectal polyps: evaluation in two years

Abstract: From June 1989, to June 1991, 58 patients with GI polyps were reviewed. Except two patients who had multiple polyps, 56 had only one polyp. The size of polyps were 0.5 to 3 em in diameter. 51 (75%) of polyps were located in the rectosigmoid region, 25 (37%) were in the rectum and 26 (38%) in the sigmoid. (Seventeen) (25%) polyps (two in right colon, four in transverse, and 11 in descending colon) were located in other regions. Patients were between nine months to 70 years old. 14 polyps were reported to be inflammatory, and 17 adenomatous. Polypectomy was done for all patients, and no massive bleeding, bacterial infection, or perforation were observed. Only five patients had slight bleeding which was treated by conservative measures. MJIRI, Vol. 6, No. 1,13-15,1992

Brucella mellitensis endocarditis: diagnosis and treatment in six adult patients.

Abstract: Brucella endocarditis is an uncommon but not rare manifestation of brucellosis in our country. We report six adult patients aged 20 to 45 years. Two of our patients were female, and this is the first time that Brucella endocarditis was reported in adult females. In five cases, aortic valve replacement was performed in addition to combined antibiotic therapy. One of them died due to immediate complica­ tion of cardiac surgery, but the others had an excellent recovery. Our study shows that medical treatment is not sufficient for Brucella mellitensis endocarditis, and urgent cardiac valve replacement must be considered. The prognosis will not be poor with combined medical and surgical therapy. MJ/RI, Vol. 6, No. I, 35-37, 1992

Rabbit isolated vas deferens possess A1 and A2 adenosine receptors.

Abstract: 1. 1. The effects of adenosine, 5′- N -ethylcarboxamidoadenosine (NECA), 2-chloroadenosine, N6-phenylisopropyladenosine ( l -PIA and d -PIA) and N6-cyclohexyladenosine (CHA) were examined on the rabbit isolated vas deferens. 2. 2. All the analogues in a concentration-dependent manner inhibited contractile response to electrical stimulation. 3. 3. 8-Phenyltheophylline caused a rightward shift of all the adenosine and its analogues' concentration-response curves. 4. 4. The order of potency for the adenosine and its analogues on the rabbit isolated vas deferens was: CHA = NECA > l -PIA > 2- chloroadenosine > d -PIA > adenosine . 5. 5. It is concluded that CHA, NECA, l -PIA, 2-chloroadenosine, d -PIA and adenosine mediate their inhibitory effects on the rabbit isolated muscle via both A 1 and A 2 adenosine receptors.

Developmental changes in morphine and clonidine sensitivity of isolated chick oesophagus.

Abstract: 1. Electrically evoked contractions of isolated newly-hatched and over 6 week-old chicks cervical oesophagus (pre-crop) were inhibited by morphine and clonidine in a dose-dependent manner. 2. The inhibitory effects of morphine and clonidine were antagonized by naloxone (3 x 10(-6) M) and yohimbine (10(-7) M), respectively. 3. IC50 for morphine was 1.01 x 10(-7) M for newly-hatched and 5.19 x 10(-6) M for adult chicks. 4. IC50 for clonidine was 2.34 x 10(-9) M for newly-hatched and 1.19 x 10(-8) M for adult chicks. 5. These findings indicate a significant decrease in inhibitory effect of morphine and clonidine during developmental stages.

A STUDY OF THE INTRACELLULAR KILLING OF THE PERIPHERAL BLOOD NEUTROPHILS IN β- THALASSEMIA MAJOR PATIENTS

Abstract: 52 Bthalassemia major patients were studied. Their ages ranged from two to 20 years. The group consisted of 22 girls and 30 boys. Candida intracellular killing and NBT (nitroblue tetrazolium) tests were performed on the peripheral blood neutrophils of these patients. Average results of the intracellular killing test was within normal range for the patients, but showed an appreciable decrease in comparison with the results of the normal control tests (50 normal persons of the same age group were tested as normal controls. This decrease was more pronounced in those patients who had undergone splenectomy. A converse relationship was observed between the results of the patients' intracellular killing and their serum ferritin level and age. Average results of the patients' NBT tests showed an increase in comparison with those of the control group. The average results for the patients who had their spleens removed due to hypersplenism was the same as in those who had normal spleens and had no relation to the serum ferritin level but did show a moderate relationship with the age of the patients. A suggestion that can be put forth is the likelihood that intracellular killing of peripheral blood neutrophils in the Bthalassemia patients is conductive to the determination of those with greater susceptibility to infection. MJ/RI. Vol. 6. No.2. 135·138, 1992 Vol11mc6 Nllmber2 TOIbesl:l1ll 1371