Collimator selection for high quality brain SPECT imaging

Different Types of collimators have been introduced in the practical usage of the gamma camera. The choice of the collimator depends firstly on the energy of the isotope, the required resolution sensitivity of the applied scan, and finally the size of the organ to be imaged. In the present study the fan-beam collimator was studied versus the parallel-hole collimator to clarify the importance of their properties in imaging of particular organs with the gamma camera. The study was done on a [Axis] dual head SPECT gamma camera provided with both parallel-hole and fan-beam collimators. The important part of this study was the clinical part at which the selected patients were coming for evaluation of the treatment response for brain tumors and detection of residual lesions or recurrence following surgical or radiotherapy treatment. Thirty patients with brain tumors of various histopathologic types including medalloblastoma, astrocytoma, glioblastoma multiformis and oligodenderoma were subjected to brain SPECT imaging. Three tests were done on each patient's reconstructed image: The ratio between the lesion average counts [total count I number of pixels] to the background average counts, the contrast of the lesion in each clinical case and the area of the lesion is also compared between the two collimators for the same patient's lesion. In conclusion fan beam is an accurate and good tool for imaging and assessment of the treatment response as well as planning in the radiotherapy unit

Simvastatin reverses cyclosporin A-induced endothelial damage in rats: lipid-lowering-dependent and -independent effects

Cydosporin A [CyA] is the immunosuppressant most frequently used in transplant surgery and in the management of autoimmune diseases. CyA-induced oxidative stress together with dyslipidemia have been implicated in the pathogenesis of vascular dysfunction associating CyA therapy. The present study investigated the possible protective effect of simvastatin, a lipid-lowering drug with potent antioxidant properties, against CyA-induced endothelial damage in male rats. Eighteen male Wistar rats were used. They were divided into 3 groups: control, CyA and CyA + simvastatin. In the control group, rats were administered the vehicle, olive oil; in the CyA group, rats were administered CyA [20 mg/kg/day, s.c. for 14 days] and in the CyA+simvastatin group, rats were co-administered simvastatin [2.5 mg/kg/day, s.c. for 14 days] and CyA. Administration of CyA [20 mg/kg/day, s.c. for 14 days] in male rats resulted in a significant increase in the lipid peroxidation product, malondialdehyde [MDA], and a significant decrease in superoxide dismutase [SOD] activity in plasma. CyA treatment was also associated with a significant increase in plasma nitrite level as well as an elevation in plasma cholesterol, triglycerides [TGs], low density lipoproteins [LDL] and a reduction in high density lipoproteins [HDL] levels. CyA-induced vascular dysfunction was further confirmed by the attenuation of endothelium-dependent relaxations produced by carbachol in rat isolated aortic rings. Co-administration of simvastatin [2.5 mg/kg/day, s.c. for 14 days] with CyA significantly reversed the deleterious biochemical and functional vascular effects that accompanied CyA treatment. The present study provides good evidence that both oxidative stress and dyslipidemia underlie the CyA-induced vascular damage, an effect that could be reversed by simvastatin co-administration

Effect of mastic gum, and vitamin e on ethanol/hcl-induced gastric ulcers in rats

Gastric ulcers were induced in the rat stomach by oral administration of ethanol/HCl [150 mM HC1 in 60% ethanol, 1 ml/ 100 g]. The protective effect of mastic gum, a resinous exudate of the tree of Pistacia lentiscus Linn Anacardiaceae, [500 mg/Kg], and vitamin E, a well known antioxidant, [100 mg/Kg] were investigated. Different gastric juice components [acidity, mucin and peptic activity] as well as gastric mucosal content of reduced glutathione, malondialdehyde, [as an index of lipid peroxidation] and prostaglandin E2 were estimated. Ethanol/HCl administration produced marked ulcers in the glandular part of rat stomach. Pretreatment with the protective agents significantly reduced the ulcer index and the protection afforded by mastic gum was greater than that of vitamin E. The protective effects of both mastic gum and vitamin E were accompanied by a significant decrease in mucosal content of malondialdehyde and a significant increase in mucosal content of reduced glutathione as compared to ethanol/HCl treated group. However, the anti-ulcer effect produced by mastic gum, only, was associated with a significant increase in mucosal content of prostaglandin E[2]. In 3-hour pylorus-ligated rats, mastic gum produced a significant decrease in free and total acidity while vitamin E caused no significant change in gastric acid secretion. The present data suggest that the anti-ulcer effect of mastic gum may be partly related to its antisecretory as well as antioxidant properties. On the other hand, the protective effect of vitamin E may be mainly related to its antioxidant effect

Tratamento das emergências hipertensivas / Treatment of hypertensive emergencies

Pacientes acometidos por emergências hipertensivas verdadeiras devem ser diagnosticados rapidamente e tratados imediatamente com drogas de ação curta, administradas por via intravenosa, sob controle médico em salas de emergência ou unidades de terapia intensiva. Entretanto, em vários centros do Brasil, esses agentes anti-hipertensivos não estão disponíveis. Nós sugerimos o nitroprussiato de sódio (0,25 μg/kg/minuto) como a melhor medicação inicial. Esse potente vasodilatador arteriolar e venular é a droga de escolha para as situações clínicas mais prevalentes, sob monitorização contínua da pressão arterial, que dever ser gradativamente reduzida em 25 cento, num período de minutos a horas. O tratamento oral ou sublingual com antagonistas de cálcio de curta ação (nifedipina -5/10 mg) é disseminado, apesar de não ser recomendado pelos especialistas, por poder determinar eventos adversos sérios. Captopril oral ou sublingual, um inibidor da enzima conversora da angiotensina, é uma opção segura para tratar urgências hipertensivas. São discutidos outros agentes anti-hipertensivos orais e sublinguais disponíveis. Uma abordagem correta é necessária para se evitar riscos de hipoperfusão em territórios críticos.

Effects of cypermethrin on lipid peroxidation and some antioxidant defense mechanisms in rats

Reactive oxygen species [ROS] have been implicated in the toxicity of various insecticides. Pyrethroids, though having the advantage of low mammalian toxicity, have been reported to produce signs of toxicity Most of these are linked to skeletal muscles. The present study tests the ability of single or repeated administration of Cypermethrin, a type II pyrethroids. to induce lipid peroxidation [LPO] in die rat brain, liver and diaphragm tissues. The study included the effect on antioxidant parameters, reduced glutathione [GSH], glutathione peroxidase [GPX], superoxide dismutase [SOD], and the protective effect of vitamin E. Single and repeated [7 days] administration of Cypermethrin [1/10 LD] induced lipid peroxidation in the rat diaphragm, while the brain and liver showed significant lipid peroxidation upon repeated administration only. This was manifested as elevation of the marker malondialdehyde [MDA]. The antioxidant defense parameter. GSH. GPX and SOD were not affected by single dose of Cypennethrin. in the rat brain or liver tissues. while, in the rat diaphragm a significant reduction in glutathione peroxidase was evident. In the rat diaphragm, repeated administration of Cypermethrin increased the level of GSH while decreased GPX activity. No significant effect was shown on the rat brain or iiver tissues. SOD activity was significantly reduced ia he diaphragm while the brain and the liver showed significant increase in the enzyme activity. Prior administration of vitamin E effectively antagonized the changes in LPO and the antioxidant parameters GSH, GPX and SOD induced by Cypennethrin. In conclusion, Cypermethrin induced LPO and an increase in the ROS. This may be linked to the mechanism underlying its insecticidal action as well as its adverse effects. Vitamin E is an effective agent to protect against the lipid peroxydative s power of Cypermethrin

Nasal low dose ketamine combined with midazolam for paediatric premedication

Sixty Children aged from three to six years scheduled for tonsillectomy or bilateral insertion of tympanotomy tubes under general anaesthesia were studied. The patients were randomly allocated into two groups where group [A] received a combination of intranasal ketamine [2 mg/kg] and midazolam [0.1 mg/kg] and group [B] received placebo [normal saline]. Anaesthesia was induced with 5% halothane and 100% 02 via face mask, subjects given intranasal combination of ketamine-midazolam were more likely to separate willingly from their parents at or before 10 minutes compared to patients given placebo. 60% of patients given this combination separated at 4 minutes compared to 20% of patients given placebo. The quality of subsequent halothane induction was excellent in 70% of patients given this combination and adequate in the remaining 30%. In 70% of patients given placebo induction was unacceptable. There were no incidents of any behavioral changes or psychological disturbances in patients given this intranasal combination. No statistically significant difference as regards recovery time was recorded between both groups. It can he concluded that nasal low dose ketamine combined with midazolam provides an effective paediatric premedication with regard to sedation and mask acceptance. It has rapid action with no prolongation of recovery time and no instances of emergence phenomena. Nasal ketamine- midazolam combination offers an alternative to intramuscular or per rectum routes for preanaesthetic sedation in young children aged from three to six years

Binding studies of some antidiabetics to serum albumin by difference spectrophotometry

The binding of several antidiabetics to serum albumin was studied by difference spectrophotometry using a spectrophotometric probe 2-[4-hydroxy-benzeneazo] benzoic acid. The calculated constants for binding of the drugs to human serum albumin were 2.38x10[6], 1.78x10[6], and 1.87x10[4] for glyburide, tolbutamide and metformin respectively. While the values of binding to bovine serum albumin were 2.89x10[5], 2.04x10[5], and 2.14x10[4] for the same drugs. Drug-probe displacement studies showed that glyburide gave the greatest probe displacement followed by tolbutamide and metformin using both human and bovine serum albumins. This order of displacement of the anionic probe indicates that both hydrophobic character and ring substituents of the ligand contribute

Epidural fentanyl and 0.5 bupivacaine for elective cesarean section. Effects on shivering, maternal and neonatal outcome / bupivacaine for elective caesarean section. Effects on shivering, maternal and neonatal outcome.

The aims of this study were to investigate whether 100 microgram fentanyl administered prophylactically by the epidural route would influence the incidence of shivering in parturients who underwent elective caesarean section under epidural analgesia and whether it would affect the maternal and neonatal outcome. Forty mothers of ASA physical status I or II presenting for elective Caesarean section were divided into two equal groups according to type of solution injected in the epidural space. Patients of Group A received 100 microgram fentanyl in addition to 0.5 percent bupivacaine while patients of group B received 0.5 percent bupivacaine alone. Shivering occurred in 20 percent of patients of group A and in 70 percent of patients of group B. There was 72 percent reduction in the incidence of shivering in mothers receiving epidural 100 microgram fentanyl with no further adverse actions on maternal and neonatal outcome. None of the neonates required resuscitation and there was no immediate or delayed respiratory depression in mothers. Only two mothers who received fentanyl required analgesic supplementation during surgery compared with ten mothers who did not receive epidural fentanyl. Another finding in our study was the markedly prolonged post-operative analgesia in patients of group A compared with group B. So, it can be concluded that the addition of 100 microgram fentanyl in the epidural space prophylactically in elective Caesarean section reduced significantly the incidence and severity of shivering and significantly improved operative comfort and duration of post-operative analgesia with no deleterious effects on neonatal and maternal outcome

Efeitos anti-hipertensivo e metabólicos a longo prazo de dozes baixas de clortalidona em pacientes de dois grupos etários com hipertensäo leve e moderada / A long-term study of the antihypertensive and metabolic effects of low doses of chlorthalidone en two groups of age with mild and moderate hypertensives

Estudamos durante um ano os efeitos anti-hipertensivo e metabólicos de doses baixas de clortalidona (25mg/dia) em 30 pacientes portadores de hipertensao arterial leve e moderada. Quinze pacientes eram maiores de 60 anos (média das idades = 66,1 anos) e 15 pacientes eram menores de 60 anos (média das idades = 48,4 anos). Observamos reduçao persistente dos níveis pressóricos em ambos os grupos de pacientes (queda na pressao sistólica de 20 a 28mmHg e na pressao diastólica de 11 a 16 mmHg) e efeitos colaterais metabólicos menos intensos se comparados àqueles induzidos pelas doses habitualmente utilizadas de tiazídicos. Calculamos também a relaçao risco/benefício em relaçao às variáveis reduçao pressórica e aumento do colesterol. Concluimos que o uso de clortalidona em doses baixas é efetivo e seguro no tratamento da hipertensoo leve e moderada, especialmente nos pacientes mais idosos.