Estrogen modulates sexually dimorphic contextual fear conditioning and hippocampal long-term potentiation (LTP) in rats

The present study examined the role of ovarian steroids in contextual fear conditioning and hippocampal synaptic plasticity in female rats. In experiment 1, adult female rats were ovariectomized and submitted to contextual fear conditioning, a procedure in which rats received unsignaled footshock in a novel observation chamber; freezing behavior served as the measure of conditional fear. Ovariectomized female rats froze at levels comparable to male rats, both of which froze significantly more than sham-operated female rats. In experiment 2, estrogen replacement in ovariectomized female rats reduced fear conditioning to a level comparable to that of sham-operated females in experiment 1. In experiment 3, the influence of estrogen on the induction of long-term potentiation (LTP) at perforant path-dentate granule cell synapses in ovariectomized female rats was examined. Estrogen decreased both population spike LTP and EPSP-spike potentiation at perforant path synapses. Taken together, these experiments indicate that ovarian steroids regulate both sexually dimorphic behavior and hippocampal plasticity in a fear-conditioning paradigm.     

Ethical dilemmas in forensic psychiatry: two illustrative cases

One approach to the analysis of ethical dilemmas in medical practice uses the "four principles plus scope" approach. These principles are: respect for autonomy, beneficence, non-maleficence and justice, along with concern for their scope of application. However, conflicts between the different principles are commonplace in psychiatric practice, especially in forensic psychiatry, where duties to patients often conflict with duties to third parties such as the public. This article seeks to highlight some of the specific ethical dilemmas encountered in forensic psychiatry: the excessive use of segregation for the protection of others, the ethics of using mechanical restraint when clinically beneficial and the use of physical treatment without consent. We argue that justice, as a principle, should be paramount in forensic psychiatry, and that there is a need for a more specific code of ethics to cover specialised areas of medicine like forensic psychiatry. This code should specify that in cases of conflict between different principles, justice should gain precedence over the other principles.     

Controlled FiO2 Therapy to Neonates by Oxygenhood in the Absence of Oxygen Analyzer

Background

A study was conducted to evaluate a system of standardizing the oxygen concentration inside the oxygen hood and to develop guidelines for controlled FiO₂ administration by changing size of the hood, lid position on the hood and the oxygen flow rate, without an oxygen analyzer. The effect of low flow rates on carbon dioxide (CO₂) retention was also studied.

Method

A dummy patient and thirty neonates, requiring oxygen to be delivered through head box, constituted the material for the study group. Oxygen content in the head box was measured using a standard oxygen analyzer while the size of head box, flow rate and lid position were changed independently and in combination. The head boxes were tested on a dummy patient. These results were analyzed, and applied to thirty neonates requiring oxygen therapy using a head box.

Result

Volume of headbox had an inverse relation with the oxygen concentration inside the headbox and smaller sized headbox achieved more predictable oxygen concentration at all flow rates. Maximum difference in oxygen concentration by varying the lid position was seen in the large headbox. Keeping the variables constant, oxygen concentration was significantly lower in babies as compared to dummy. No significant CO₂ retention was found at a flow rate of four litres per minute (lpm) in small and three lpm in a medium and large head box respectively, while lower flow rates were associated with CO₂ retention.

Conclusion

It is possible to predict the oxygen concentration inside the head box without the use of oxygen analyzer. Larger head box and higher lid position, results in lower oxygen concentration, at a given oxygen flow rate. Oxygen concentration achieved in babies is lesser than the concentration achieved in a dummy. Flow rates of less than four lpm in small and three lpm in medium and large sized head boxes are associated with CO₂ retention. These results are not applicable to infants weighing less than 2 kg.Key Words: Neonates, Oxygen therapy, Oxygen hood, Oxygen concentration, Oxygen analyzer     

Management of Rh-isoimmunised Pregnancies : Our Experience

Background

The aim of this study was to assess the role of middle cerebral artery peak systolic velocity (MCA-PSV), as measured by doppler ultrasound, in detecting foetal anaemia in Rh- isoimmunised pregnancies. Intra-uterine foetal blood transfusion was performed in such anaemic foetuses to tide over the crisis of foetal immaturity till considered fit for extra-uterine survival.

Methods

Rh-isoimmunised pregnancies reporting to a tertiary institute from 2003 to 2005, were screened by doppler ultrasound to estimate MCA-PSV to detect foetal anaemia. If the foetus developed MCA-PSV of more than 1.5 multiple of median (MoM) for the gestational age, foetal blood sampling through cordocentesis was performed to confirm foetal anaemia, followed by intrauterine foetal blood transfusion to all anaemic foetuses at the same sitting. Neonatal outcome was evaluated by recording gestational age at the time of delivery, duration of gestational time gained and need for blood transfusion in the neonatal period.

Results

A total of thirteen isoimmunised pregnancies were evaluated. Three pregnancies did not require in-utero foetal blood transfusion. Twenty-one intrauterine foetal blood transfusions were performed in the remaining ten patients. Five received blood transfusion in the neonatal period. Intra uterine foetal death occurred in one grossly hydropic foetus and favourable neonatal outcome was recorded in the rest.

Conclusion

The clinical outcome of these pregnancies justifies the use of doppler studies of MCA-PSV in detecting foetal anaemia and intra uterine foetal blood transfusion is the only hope of prolonging pregnancy and salvaging such foetuses.Key Words: Rh-isoimmunisation, Middle cerebral artery peak systolic velocity, Foetal anaemia, Foetal blood transfusion     

Clinical observation on treatment of depression by electro-acupuncture combined with Paroxetine

Objective:To observe the clinical efficacy and adverse reactions of Paroxetine combined with electro-acupuncture (EA) in treating depression.Methods:Forty-two patients with depression were randomly assigned to the observation group (22 patients) treated with EA combined with Paroxetine,and the control group (20 patients) treated with Paroxetine alone,and the therapeutic course for both groups was 6 weeks.The therapeutic efficacy and adverse reactions were evaluated with scores by Hamilton depression scale (HAMD) and treatment emergent symptoms scale (TESS), respectively.Results:HAMD scores determined at the end of the 1st,2nd,4th,and 6th week of the treatment course were significantly lower in the observation group than those in the control group (P<0.05).The significant improvement rate evaluated at the end of the 6-week treatment was remarkably higher in the observation group than that in the control group (72.7% vs 40.0%).No significant difference of TESS scores was found between the two groups.Conclusion:EA combined with Paroxetine has better clinical efficacy than that of Paroxetine alone,with milder adverse reaction and quicker initiation of effect.     

Anxiogenic potential of ciprofloxacin and norfloxacin in rats

INTRODUCTION: The possible anxiogenic effects of fluoroquinolones, namely ciprofloxacin and norfloxacin, were investigated in adult Charles Foster albino rats of either sex, weighing 150-200 g. METHODS: The drugs were given orally, in doses of 50 mg/kg for five consecutive days and the experiments were performed on the fifth day. The tests included open-field exploratory behaviour, elevated plus maze and elevated zero maze, social interaction and novelty-suppressed feeding latency behaviour. RESULTS: The results indicate that ciprofloxacin- and norfloxacin-treated rats showed anxious behaviour in comparison to control rats in all the parameters studied. However, ciprofloxacin- and norfloxacin-treated rats did not differ significantly from each other in various behavioural parameters. CONCLUSION: The present experimental findings substantiate the clinically observed anxiogenic potential of ciprofloxacin and norfloxacin.     

Cortical interference effects in the cocktail party problem

Humans and animals must often discriminate between complex natural sounds in the presence of competing sounds (maskers). Although the auditory cortex is thought to be important in this task, the impact of maskers on cortical discrimination remains poorly understood. We examined neural responses in zebra finch (Taeniopygia guttata) field L (homologous to primary auditory cortex) to target birdsongs that were embedded in three different maskers (broadband noise, modulated noise and birdsong chorus). We found two distinct forms of interference in the neural responses: the addition of spurious spikes occurring primarily during the silent gaps between song syllables and the suppression of informative spikes occurring primarily during the syllables. Both effects systematically degraded neural discrimination as the target intensity decreased relative to that of the masker. The behavioral performance of songbirds degraded in a parallel manner. Our results identify neural interference that could explain the perceptual interference at the heart of the cocktail party problem.     

Heavy Metal Pollution Characteristics in the Modern Sedimentary Environment of Northern Jiaozhou Bay,China

The particle size distribution characteristics of sediments and the concentrations of heavy metals in Jiaozhou Bay were investigated in this study. The average concentrations of Cu, Pb, Zn, Cr, Cd, Hg and As were 36.88, 29.60, 82.08, 77.48, 0.083, 0.048 and 11.00 mg/kg, respectively. The heavy metal concentrations were highest in the eastern sediments, followed by those at the top of the bay, and the lowest concentrations were observed in the central region. Overall, a decreasing trend from the center of the bay to the periphery was observed. Additionally, the distribution of heavy metals in sediments was not completely controlled by sediment particle size. The degree of heavy metal contamination was evaluated using the geoaccumulation index and Hakanson’s method. The results revealed that the level of heavy metal pollution in the sediments was relatively low and that the main pollution elements were Cu and Hg. In addition, the sediments are associated with various levels of potential ecological risk due to the high pollution levels of Hg and Cd.     

IGF-I enhances cortisol secretion from guinea-pig adrenal gland: in vivo and in vitro study

Insulin-like growth factor (IGF)-I is a ubiquitously synthesized peptide that, along with IGF-II, acts via the IGF-R type I receptor. IGF-I and its receptor are expressed in the adrenal gland of humans and bovines, the secretion of which they seem to stimulate. As in humans and cows, the main glucocorticoid hormone secreted by guinea-pig adrenals is cortisol, and hence we have studied the adrenocortical effects of IGF-I in this species. In vivo experiments showed that prolonged IGF-I administration raised the plasma concentration of cortisol in both normal and dexamethasone/captopril-treated guinea pigs, thereby ruling out the possibility that IGF-I may act by activating the hypothalamic-pituitary-adrenal axis and the renin-angiotensin system. In vitro experiments demonstrated that IGF-I enhanced basal, but not maximally agonist [ACTH and angiotensin-II (Ang-II)]-stimulated, cortisol secretion from freshly dispersed guinea-pig inner adrenocortical cells. The IGF-I immuno-neutralization suppressed the IGF-I secretagogue effect, without altering the cortisol response to both ACTH and Ang-II. IGF-I raised cyclic-AMP and inositol triphosphate release from dispersed guinea-pig cells, and the effect was reversed by the adenylate cyclase inhibitor SQ-22536 and the phospholipase-C (PLC) inhibitor U-73122. SQ-22536, U-73122, the protein kinase (PK) A inhibitor H-89 and the PKC inhibitor calphostin-C decreased by approximately 50% the cortisol response of dispersed cells to IGF-I, and the combined exposure to SQ-22536 and U-73122 abolished it. We conclude that IGF-I stimulates glucocorticoid secretion from guinea-pig adrenocortical cells, acting via selective receptors coupled to both the adenylate cyclase/PKA- and PLC/PKC-dependent signaling cascades.