Identification of resistance to Sugarcane mosaic virus, Sugarcane streak mosaic virus, and Sugarcane bacilliform virus in new elite sugarcane accessions in India

Sugarcane mosaic and leaf fleck diseases are significant viral diseases affecting sugarcane crops in India. The use of resistant sugarcane varieties is considered the most economical and effective approach to manage viral diseases, especially in vegetatively propagated crops such as sugarcane. Sugarcane mosaic virus (SCMV) and Sugarcane streak mosaic virus (SCSMV) are the primary pathogens responsible for mosaic disease in sugarcane-growing regions of India. Sugarcane bacilliform virus (SCBV), causing leaf fleck disease, is also often found in mixed infections with mosaic symptoms. The study aimed to identify new sources of resistance by screening sugarcane germplasm for resistance to SCMV, SCSMV, and SCBV. The screening was carried out under high inoculum using the infector row method in both plant and ratoon crops. Out of 129 genotypes tested, only 8 were found to be free of mosaic viruses, indicating a rare occurrence of resistant sources. The study revealed that mosaic disease is widespread, with nearly 95% of tested varieties/genotypes being infected with mosaic viruses. SCMV, SCSMV, and SCBV were detected in 121 out of 129 genotypes using the RT-PCR and PCR assays. Based on their response to the viruses, the tested genotypes were categorized into different resistance grades: highly resistant (grade 1), resistant (grade 2), moderately resistant (grade 3), susceptible (grade 4), and highly susceptible (grade 5). The results of the study provide valuable information about elite resistance resources that can be used for the prevention and control of mosaic disease. These resistant genotypes could also serve as potential donors for mosaic and leaf fleck disease resistance in breeding programs.

Detection of Sugarcane bacilliform virus in diseased sugarcane plants in Andhra Pradesh, India by serological and molecular methods

Sugarcane leaf fleck incited by Sugarcane bacilliform virus is emerging as a major disease and affecting exchange of sugarcane germplasm and cultivation worldwide. Roving surveys conducted in 162 fields belonging to 81 villages spread over 14 sugarcane growing districts of Andhra Pradesh during 2021-2022 revealed 8 to 44% incidence of the disease. Mean maximum fleck disease incidence was reported in Anakapalli district (33.00%) followed by Srikakulam district (22.66%), whereas least incidence was observed in Alluri Sitharamaraju district (9.33%). The early and sensitive detection of pathogens is vital and necessary to reduce the danger of introducing new diseases or pathogen strains into sugarcane growing regions. Both serological and molecular methods were used in proposed investigation to identify the virus at the protein and nucleic acid levels. DAS-ELISA results were positive for 50 suspected SCBV infected sugarcane leaf samples out of 81, with mean absorbance (A405) values ranging from 0.50 to 2.20. Further PCR assays were performed using SCBV-specific primers targeting RT/RNase H coding region which is frequently employed as a taxonomic marker for species delineation in Badnaviruses. Out of 81 symptomatic samples collected, 61 samples gave positive results, and no amplification was observed in healthy control and negative control. Results made it evident that PCR was more sensitive than DAS-ELISA. Low virus concentration or variation in virus strains may be the reason for the low detection rate in DAS-ELISA in the current study. Extensive roving surveys conducted for the incidence of leaf fleck disease for the first time in the state of Andhra Pradesh revealed severe occurrence of leaf fleck disease under field conditions.

Hybrid Ameloblastoma Arising from a Treated Odontogenic Keratocyst of the Mandible: A Case Report With Literature Review

Odontogenic Keratocyst (OKC) is an odontogenic cyst of developmental origin arising from remnants of the dental lamina. Malignant or benign transformations though rare have been noticed from their epithelium. Ameloblastomatous transformation from an OKC is extremely rare with such lesions being referred to as combined/"hybrid" odontogenic lesions. In this article, we present an intriguing case of a 60-year-old male who was operated on for OKC of the anterior mandible 3 years before, who came back with a complaint of swelling over the same site. Incisional biopsy revealed the acanthomatous type of ameloblastoma for which segmental resection with immediate reconstruction using recon plate was done. Excision biopsy revealed a plexiform variant as well, thus exhibiting a hybrid pattern. Surgeons should be aware of this hybrid presentation of ameloblastoma arising from the epithelium of OKC as the acanthomatous subtype is known for its notorious genetic behavior leading to recurrence and aggressive nature of this tumor.

New record of mungbean yellow mosaic India virus in Desmodium laxiflorum and association of bhendi yellow vein mosaic betasatellite in Abelmoschus moschatus in Andhra Pradesh, India

Mungbean yellow mosaic India virus (MYMIV) is one of the most serious commonly occurring yellow mosaic virus (YMV's) group in majority of the pulses especially black gram and green gram in southern India compared to previously reported mungbean yellow mosaic virus. In January 2020 Desmodium laxiflorum and Abelmoscus moschatus showing mosaic symptoms and vein yellowing were collected from Guntur and Prakasam districts respectively in Andhra Pradesh. PCR analysis using MYMIV and betasatellite specific primers gave desired expected amplification from the infected samples of A. moschatus (YMV-ABEL) whereas only MYMIV specific amplification was obtained in D. laxiflorum (YMV-DES). However, no PCR amplification was obtained in respective healthy leaf samples of both plants. Sequence analysis showed that the CP sequence of YMV-ABEL and YMV-DES showed a similarity of 99.19% with MYMIV (KP677496) and 99.75% with MYMIV (JN181003) respectively. The full-length betasatellite (1356 bp) showed highest identity of 90% with bhendi yellow vein mosaic betasatellite (BYVMB) (GU111977). Phylogenetic analysis clustered the test isolates with south Indian isolates of MYMIV whereas the betasatellite sequence clustered with various isolates of BYVMB, tomato leaf curl New Delhi virus betasatellite and okra leaf curl betasatellite reported from India and Pakistan. To the best of our knowledge, this is the first report of a MYMIV in D. laxiflorum and A. moschatus and MYMIV betasatellite complex in A. moschatus.

Deep Learning – A Review

In recent years, tech giants in various parts are showing Curiosity on Artificial Intelligence by investment on the project that can be a game-changer for both corporate and researchers. A company such as Google, Baidu, and Yandex have already started their multimillion-dollar project in this pitch. This article presents the latest progress and also tries to paint a predictive picture of future research directions and developments in the domain of deep learning. Each of the said research directions and avenues is analyzed and summarized in a brief yet concise manner in this article. Initially, an outline of the three elementary models of deep learning that including multilayer perceptions and perceptrons, convolutional neural networks and recurrent neural networks. Building on the bases of foundation, further analyses of the emerging new types of convolutional neural networks and recurrent neural networks are also undertaken in this current study. This article then summarizes deep learning and its applications in the domain of artificial intelligence, counting speech processing, computer vision, and natural language processing. Finally, the purpose of deep learning is discussed. The current article also delves a little deeper into the inner workings of the neural networking architecture associated with object detection and computer vision.

Protective effect of Allium sativum (garlic) aqueous extract against lead-induced oxidative stress in the rat brain, liver, and kidney

The present investigation was undertaken to evaluate the ameliorative activity of Allium sativum against lead-induced oxidative stress in the brain, liver, and kidney of male rats. Four groups of male Wistar strain rats (100-120 g) were taken: group 1 received 1000 mg/L sodium acetate and group 2 was given 1000 mg/L lead acetate through drinking water for 2 weeks. Group 3 and 4 were treated with 250 mg/kg body weight/day of A. sativum and 500 mg/kg body weight/day of A. sativum, respectively, by oral intubation for a period of 2 weeks along with lead acetate. The rats were sacrificed after treatment and the brain, liver, and kidney were isolated on ice. In the brain, four important regions namely the hippocampus, cerebellum, cerebral cortex, and brain stem were separated and used for the present investigation. Blood was also drawn by cardiac puncture and preserved in heparinized vials at 4 °C for estimation of delta-aminolevulinic acid dehydratase (ALAD) activity. The results showed a significant (p < 0.05) increase in reactive oxygen species (ROS), lipid peroxidation products (LPP), total protein carbonyl content (TPCC), and lead in the selected brain regions, liver, and kidney of lead-exposed group compared with their respective controls. Blood delta-ALAD activity showed a significant (p < 0.05) decrease in the lead-exposed rats. However, the concomitant administration of A. sativum resulted in tissue-specific recovery of oxidative stress parameters namely ROS, LPP, and TPCC. A. sativum treatment also restored the blood delta-ALAD activity back to control. Overall, our results indicate that A. sativum administration could be an effective antioxidant treatment strategy for lead-induced oxidative insult.

Tuberculosis of gallbladder with candidiasis, a rare entity

Gallbladder tuberculosis (GT) is an extremely rare condition. This is thought to be due to the protective property of bile against the infection. Clinical and radiological diagnosis of GT is difficult. We describe a case of GT who initially presented to us with jaundice, a right hypochondrial mass and computed tomographic findings suggestive of gallbladder empyema. Diagnosis was made from histopathological examination of the resected gallbladder which revealed epitheloid granulomas with caseating necrosis and presence of Langhan's giant cells. From a literature search and to the best of our knowledge, this is the first GT to be reported in South East Asia.

Trends of breast cancer treatment in Sabah, Malaysia: a problem with lack of awareness

INTRODUCTION

Sabah, formerly known as North Borneo, is part of East Malaysia. 52.2 percent of patients with breast cancer in Sabah presented at advanced stages and up to 20.4 percent of patients defaulted proper treatment, opting for traditional therapy. We performed a two-year prospective study looking at the treatment trends of breast cancer in Sabah.

METHODS

Our subjects were all newly-diagnosed breast cancer cases seen at the hospital in 2005 and 2006. Type of surgery, chemotherapy, radiotherapy, hormonal therapy and surgical complication for each patient were studied.

RESULTS

Out of 186 newly-diagnosed cases, 152 (81.7 percent) had surgery, 126 (67.7 percent) had chemotherapy, 118 (63.4 percent) had radiotherapy and 92 (49.5 percent) had hormonal therapy. 18.3 percent did not have surgery either due to refusal of treatment or advanced disease. They were more likely to be non-Chinese (91.1 percent, p-value is 0.02). Only 15.8 percent had breast-conserving surgery. The most frequent surgical complication was seroma formation (15.0 percent) . The commonest chemotherapy regime and hormonal therapy were anthracycline-based regime (88.1 percent) and tamoxifen (95.8 percent), respectively.

CONCLUSION

The proportion of breast-conserving surgery and usage of modern adjuvant therapies are low in Sabah. This can be attributed to lack of breast cancer awareness leading to late presentation and refusal of treatment, coupled with insufficient health service funding.

Successful endovascular treatment of post-traumatic inferior pancreaticoduodenal artery pseudoaneurysm

True and pseudoaneurysms of the visceral arteries are uncommon. They represent 0.1-0.2 percent of all vascular aneurysms. Visceral artery aneurysms (VAAs) should be treated due to their propensity to rupture and associated high mortality. We describe a 58-year-old man with pseudoaneurysm of the inferior pancreaticoduodenal artery and who presented with post-motor vehicle accident abdominal pain and a pulsatile epigastic mass. Computed tomography (CT) showed a pseudoaneurysm of the visceral artery, and selective mesenteric angiography showed the aneurysm to be arising from the inferior pancreaticoduodenal artery. The aneurysm was successfully treated with endovascular coil embolisation. CT angiogram at one month post-procedure revealed persistent occlusion of the aneurysm. To the best of our knowledge, this is the first reported pseudoaneurysm of inferior pancreaticoduodenal artery secondary to blunt abdominal trauma from a motor vehicle accident and also the first reported VAA from Malaysia.

Synchronous adenocarcinoma of caecum, transverse colon and jejunum

Synchronous cancers are defined as malignant tumours that occur simultaneously, each of which must be distinct with no possibility of one being the metastasis of the other. A 65 year old gentleman presented to us with two month history of epigastric pain associated with anaemia, loss of appetite and weight. He has no history of malignancy in his family. Colonoscopy revealed tumours at transverse colon and caecum. Intra-operatively, tumours were sited at caecum, transverse colon and jejunum. Tumours were diagnosed as synchronous adenocarcinoma histopathologically with loss of expression of MLH1 and MSH2. From literature search, this is the first reported triple synchronous tumours of the caecum, transverse colon and jejunum. We believe that this gentleman developed triple synchronous tumour through the sporadic MSI pathway.

Role of routine chest radiography after percutaneous dilatational tracheostomy

BACKGROUND

The role of routine chest radiography (CXR) after percutaneous dilatational tracheostomy (PDT) has been questioned.

METHODS

We performed a prospective observational study, on a mixed medical/surgical critical care unit in a university teaching hospital. We studied all patients undergoing PDT as part of their critical care management from November 1, 2003 until July 31, 2007. All PDTs were performed under bronchoscopic guidance. After PDT, we reviewed the immediate post-procedural films to assess the utility of routine postoperative CXR. For the purposes of CXR review, we considered a procedure to be either uncomplicated or technically difficult. Clinically relevant CXR findings were new barotrauma (pneumothorax, pneumomediastinum) or a significant change in consolidation from the pre-procedure film.

RESULTS

A total of 384 patients underwent PDT during the study period. Of these, 345 had immediate post-procedural CXRs available for review. There were 252 PDTs (73%) documented as uncomplicated. There were 93 (27%) technically difficult procedures, with 107 adverse events recorded. In 82 (24%) procedures, these difficulties were described as minor procedural complications [multiple attempts at needle insertion (> or = 3), minor bleeding or tracheal ring fracture]. Significant complications (mal-placement in the anterior mediastinum and major bleeding) were documented in 12 (3.5%) patients. New abnormalities were noted on 8 (2.3%) immediate post-procedural CXRs. In only one patient was there a new CXR change in an uncomplicated PDT.

CONCLUSIONS

Immediate CXR after uncomplicated PDT performed under bronchoscopic guidance rarely reveals unexpected radiological abnormalities. The role of CXR after PDT appears to be restricted to those patients undergoing technically difficult and complicated procedures. A change in practice to this effect will lead to reductions in both medical costs and exposure of staff and patients to ionizing radiation.

Brain areas activated after ejaculation in healthy young human subjects

Brain mechanisms for the refractory period that characteristically follows ejaculation in animals and human are poorly understood. The possibility of active inhibition of brain areas being responsible for the post-ejaculatory inhibitory state has not been ruled out. Using Blood Oxygen Level Dependent (BOLD) functional magnetic resonance imaging (fMRI) we have mapped brain areas in healthy young volunteers immediately after ejaculation. Functional imaging of the brain for 30 minutes beginning after three minutes of ejaculation induced by masturbation showed spatio-temporal activation in amygdala, temporal lobes and septal areas. The septal areas were observed to be active for a shorter duration than the amygdala and the temporal lobe. Thus the temporal sequence of involvement of the above neural structures may contribute to temporary inhibition of sexual arousal/penile erection during the post-ejaculatory refractory period in humans.

Tonic activity of alpha1 adrenergic receptors of the medial preoptic area contributes towards increased sleep in rats

Several studies have suggested that noradrenergic afferents to the medial preoptic area might be involved in hypnogenesis and in lowering the body temperature, and that the alpha1 adrenergic receptors might be mediating these responses. This study was undertaken to find out the changes in sleep-wakefulness and body temperature in rats, when these adrenergic receptors of the medial preoptic area are blocked by alpha1 selective antagonist, prazosin. Adult male Wistar rats were chronically implanted with electrooculogram, electroencephalogram and electromyogram electrodes for sleep-wakefulness assessment, and a bilateral guide cannula for microinjection of prazosin at the medial preoptic area. A radio-transmitter was implanted in the abdomen for telemetric measurement of body temperature in four groups of rats. Sleep-wakefulness was also assessed telemetrically in four other groups of rats. Sleep-wakefulness recordings from these rats were done in a specialized chamber, where they could move about freely and select the ambient temperature which they prefer. Prazosin induced a dose dependent increase in wake period and in body temperature, when microinjected into the medial preoptic area. Results suggest that preoptic alpha1 adrenergic receptors mediate hypnogenic and hypothermic responses. It is proposed that the noradrenergic afferents to the medial preoptic area, by tonic activation of alpha1 adrenergic receptors, contribute towards increase in sleep especially during the daytime.

Differences in the effects of medial and lateral preoptic lesions on thermoregulation and sleep in rats

The effects of the destruction of the medial preoptic area and the lateral preoptic area with N-methyl-d-aspartic acid on sleep-wakefulness, brain temperature and thermoregulation were studied in two groups of male Wistar rats. Electroencephalogram, electrooculogram and electromyogram, along with brain temperature, were recorded for 3 days, prior to the destruction of the medial preoptic area and the lateral preoptic area, and on the 7th and 21st days after the destruction of these areas. The thermoregulatory capacity of the rats was assessed by recording their brain temperature when they were exposed to severe cold (5+/-1 degrees C) and heat (37+/-1 degrees C) before and after the lesion. Though sleep was decreased after the destruction of both the medial preoptic area and the lateral preoptic area, paradoxical sleep was reduced only by the destruction of the medial preoptic area. Decrease in sleep after the medial preoptic area lesion was brought about by a decrease in the duration of the slow wave sleep episodes and the frequency of paradoxical sleep episodes. Decrease in sleep after the lateral preoptic area lesion was brought about by a decrease in the frequency of slow wave sleep episodes. There was a significant increase in brain temperature after the medial preoptic area lesion but not after the lateral preoptic area lesion. The rats with lesion in the medial preoptic area showed deficits in thermoregulation on exposure to cold, while those with the lateral preoptic area lesion showed deficits in heat defense ability. The present findings suggest that the medial preoptic area and the lateral preoptic area regulate sleep by different modalities and that there is an anatomical segregation of heat and cold defense functions within the basal forebrain.

Gating of the dorsal penile nerve inputs by norepinephrine at the medial preoptic area in rats

The medial preoptic area neurons related to male sexual behaviour in rats were identified by their responses to dorsal penile nerve stimulation. These neurons were further tested with norepinephrine applied iontophoretically. From the 21 medial preoptic area neurons recorded in urethane anaesthetized rats, 17 neurons responded to dorsal penile nerve stimulation. Excitatory and inhibitory responses were found in almost equal number of neurons. 14 neurons responded to norepinephrine application, out of which six neurons were excited and eight were inhibited. The direction of changes produced by dorsal penile nerve stimulation and norepinephrine application were similar in 10 neurons. The results suggest that the sensory inputs from the genitalia are possibly gated by norepinephrine at the level of the medial preoptic area. Afferent information from the genitalia carried by dorsal penile nerve and the availability of norepinephrine at the level of the medial preoptic area probably help in maintaining adequate level of sexual arousal.

Atenolol or butoxamine injection at the lateral septum doesn't inhibit male sexual behavior in rats

To investigate the role of specific adrenoreceptors subtypes on sexual behavior, atenolol, butoxamine, a mixture of atenolol and butoxamine, and saline (vehicle) were injected into the lateral septum in four different groups of sexually active male rats. Application of a mixture of atenolol and butoxamine produced inhibition of copulatory activity. On the other hand, application of either atenolol or butoxamine alone did not inhibit copulatory activity. But it produced stimulation of some of the components of male sexual behavior. Inability of either atenolol or butoxamine to inhibit the male sexual behavior, and inhibition of the same by the mixture of atenolol and butoxamine, indicate that both beta-adrenoreceptors at the lateral septum are involved in the elaboration of male sexual behavior. Stimulation of some components of sexual behavior on application of atenolol or butoxamine could be attributed to an unbalanced activity of beta-adrenoreceptors.

First Report of Tobacco streak virus Infecting Safflower (Carthamus tinctorius) in Maharashtra, India

Safflower, Carthamus tinctorius L. (Asteraceae), is extensively cultivated in India, China, and other parts of Asia for edible oil, dyeing agent, and its medicinal value. In 2003, safflower entry (NARI-6) in the All-India Coordinated Research Project on Oilseeds (Safflower) grown in the experimental fields of M/s Syngenta India Ltd., Aurangabad (Maharashtra State, India) exhibited symptoms of veinal and leaf necrosis, necrotic streaks on the stem, necrosis of the terminal bud, and ultimately plant death. The disease was attributed to Tobacco streak virus (TSV) because sunflower growing adjacent to safflower showed similar symptoms caused by TSV (1). Mechanical inoculations of sap from symptomatic safflower leaves caused typical symptoms of TSV (local, irregular, necrotic rings, veinal necrosis, and systemic veinal necrosis) on Vigna unguiculata (L.) Walp. cv. C-152 and Phaseolus vulgaris (L.) cv. Topcrop, and symptoms of local, necrotic lesions, veinal necrosis, and systemic necrosis of leaf and growing bud on Arachis hypogaea L. cv. JL-24. Sap-inoculated safflower cv. Manjeera showed chlorotic and necrotic local lesions followed by systemic leaf necrosis, leading to necrosis and death of the terminal bud. Safflower cvs. A-1, BIP-2, Co-1, and Bheema (10 plants of each cultivar) inoculated with sap from safflower plants showing typical TSV symptoms did not show any visible symptoms except stunting, but six to nine plants of each cultivar tested positive for TSV using enzyme-linked immunosorbent assay (ELISA) tests. In direct antigen coating-ELISA, the virus reacted positively with antiserum produced to an isolate of TSV from peanut (2) and to antiserum to TSV (ATCC-PVAS 276 for Datura stramonium), but did not react to peanut bud necrosis tospovirus antiserum. Examination of leaf extracts using leaf-dips and immunosorbent electron microscopy with the antiserum of TSV-peanut isolate showed isometric particles resembling those in the genus Ilarvirus. To our knowledge, this is the first report of an isolate of Tobacco streak virus infecting safflower. References: (1) R. D. V. J. Prasada Rao et al. J. Oilseeds Res. 17:400, 2000. (2) A. S. Reddy et al. Plant Dis. 86:173, 2002.

Orexin A (hypocretin-1) application at the medial preoptic area potentiates male sexual behavior in rats

The medial preoptic area plays an important role in the regulation of male sexual behavior in rats, and this area receives orexinergic inputs. The role of orexinergic inputs in the medial preoptic area in sexual behavior has not been studied, though they have been shown to play a role in some other physiological functions. In this study, the changes in male sexual behavior in rats were studied after local injection of orexin A (Hypocretin-1) at the medial preoptic area. The results of the study showed that orexin A application at the medial preoptic area increased sexual arousal as well as the copulatory performance. Sexual arousal is one of the physiological stimuli, which influences wakefulness. It is possible that the earlier reports showing increased wakefulness, on application of orexin A at the medial preoptic area/basal forebrain, has a contribution from sexual arousal.

Alterations in monoamine neurotransmitters and dendritic spine densities at the medial preoptic area after sleep deprivation

The experiments were conducted on 24 adult male Wistar rats to find out the alterations in the levels of monoamines and dendritic spine densities in the medial preoptic area and cortex after total sleep deprivation. Noradrenaline was reduced in the medial preoptic area, though there was no significant change in the cortex. Dopamine and serotonin were decreased both in the medial preoptic area and in the cortex. Dendritic spine counts in the medial preoptic area and the motor cortex were increased after total sleep deprivation. Enhanced release of the monoamines and their subsequent breakdown during sleep deprivation could be responsible for the decreased levels of the transmitters. An increase in synaptic activity, resulting in the enhanced release of the transmitters, might be responsible for the increased spine density after total sleep deprivation. Localized changes in noradrenaline levels at the medial preoptic area suggest its involvement in sleep genesis and maintenance, though its possible contribution to other functions like thermoregulation and reproduction cannot be ruled out. As the available literature does not indicate a role for serotonin and dopamine at the medial preoptic area in sleep regulation, these changes may represent their participation in non-sleep functions.

Effect of ambient temperature on sleep-wakefulness in normal and medial preoptic area lesioned rats

The changes in sleep-wakefulness were studied in rats during their exposure to different ambient temperatures of 18 degrees C, 24 degrees C and 30 degrees C, before and after the destruction of the medial preoptic area neurons by N-Methyl D-aspartic acid. In normal rats, there was an increase in paradoxical sleep and slow wave sleep and a decrease in wakefulness at higher ambient temperatures. The increase in sleep was primarily due to an increase in the duration of sleep episodes. Destruction of the medial preoptic area neurons produced a decrease in sleep at all three different ambient temperatures. But, there was a linear increase in sleep with higher temperatures in the lesioned rats that was qualitatively different from that in the normal animals, as the increase in sleep was associated with an increase in the number of short duration slow wave sleep episodes. The findings indicate that the medial preoptic area is essential for sleep maintenance and improving the quality of sleep with higher ambient temperatures. It is possible that the medial preoptic area serves as a fine-tuning mechanism to regulate sleep for energy homeostasis, including thermoregulation.

Role of the medial preoptic area in thermal preference of rats

This study was conducted to find out whether the medial preoptic area (mPOA) plays a role in the selection of ambient temperature by rats. Adult male Wistar rats were kept in an environmental chamber having three interconnected compartments, maintained at three different temperatures (18 degrees, 24 degrees and 30 degrees C) in which the animals could move freely from one compartment to the other. Normal rats preferred to stay at the chamber maintained at 24 degrees C for most of the time, during day and night. The temperature preference shifted to 30 degrees C after the mPOA of these rats had been lesioned by local administration of 5 micrograms of N-methyl D-aspartic acid (NMDA) in 0.2 microliter distilled water. The results of the study suggest that the mPOA acts as a fine tuning center for homeostatic regulation of thermal balance, including selection of appropriate thermal environment. It is proposed that after the mPOA lesion, the animal cannot assess properly the energy status of the body and thereby prefers a higher ambient temperature.

Micropropagation of Paulownia fortuneii through in vitro axillary shoot proliferation

Primary cultures were established with nodal segments from juvenile shoots of two- year-old Paulownia fortuneii trees from a clonal plantation in Andhra Pradesh. A medium containing half-strength MS salts + RAP (1 mg/L) + sucrose (2%) produced optimum bud break in nodal explants. The same basal medium with reduced hormone level (0.5 mg/L) supported maximum multiplication of secondary cultures of P. fortuneii (1:6 in 6 weeks). Specific treatments were tested to enhance this rate of multiplication. In one approach, five to six week old in vitro grown shoots were ratooned (cutting the main shoot at the bottom leaving one node). The stumps (ratooned basal node) produced 2 to 3 axillary shoots, which grew into 4 to 5 nodes by 3 weeks; thus, providing additional shoots from the same explant. This provided 30% additional shoots in 4 cycles. Secondly, reducing the light intensity to 1200 lux resulted in higher shoot elongation, i.e, formation of 8 nodes in 5 weeks with healthier shoots than the normal intensity of 3000 lux under which only 6 nodes were produced in 6 weeks. In vitro-grown shoots could be successfully rooted ex vitro in vermiculite + cocopeat mixture (1:1 v/v) under 90% humidity, transferred to soil in polybags for hardening in the green house for 2 weeks and shifted to shade net for further hardening. After one month, the plants could be successfully transplanted to field with 95% survival. Micropropagated plants showed an excellent growth in the field attaining a height of 1.5 m and a collar diameter of 2.8 cm in 3 months.

Increased lipid peroxidation of erythrocytes in blood stored in polyvinyl chloride blood storage bags plasticized with di-[2-ethyl hexyl] phthalate and effect of antioxidants

BACKGROUND AND OBJECTIVES

Previous work in this laboratory has shown significant decrease in vitamin E in erythrocytes in blood stored in polyvinyl chloride (PVC) bags plasticized with di-[2-ethyl hexyl] phthalate (DEHP), and in erythrocytes incubated in vitro with DEHP. Since vitamin E is a major antioxidant, a study was carried out to find out whether this decrease observed in vitamin E has an effect on lipid peroxidation in blood stored in DEHP-plasticized PVC blood bags.

MATERIALS AND METHODS

Blood was collected in Penpol blood storage bags (which is a DEHP-plasticized PVC bag) and parameters of lipid peroxidation, i.e. activity of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, concentration of malondialdehyde (MDA), conjugated dienes, hydroperoxides, glutathione and vitamin E studied in erythrocytes after various periods of storage as compared to glass bottles. Erythrocytes were also incubated in vitro with DEHP with and without vitamin E, and changes in lipid peroxidation studied.

RESULTS

Blood stored in Penpol bags showed increased lipid peroxidation in erythrocytes as compared to that stored in glass bottles, as is evident from a greater increase in MDA and a greater decrease in glutathione and a significant decrease in vitamin E. The addition of vitamin E decreased the formation of MDA and conjugated dienes and prevented the decrease in vitamin E. However in spite of increased lipid peroxidation in the presence of DEHP, the release of K+ and hemoglobin from erythrocytes was lower. When there was an increase in DEHP taken up by erythrocytes, there was a corresponding decrease in vitamin E. More important, whenever there was an increase in vitamin E in erythrocytes (when RBCs in the presence of DEHP were incubated with vitamin E), there was a progressive decrease in DEHP.

CONCLUSION

DEHP caused increased lipid peroxidation in erythrocytes. At the same time, it decreased the release of K+ and hemoglobin from erythrocytes. It is possible that the stabilizing effect of DEHP on the erythrocyte membrane may offset the detrimental effects of the increased lipid peroxidation it causes.

Neural regulation of glucose homeostasis

The regulation of blood glucose is generally stated to be under the control of the endocrine system. But the endocrine secretion is itself regulated by the central nervous system, especially the hypothalamus. The brain can sense the energy status of the body by using neural afferent signals and metabolic cues such as glucose. A variety of experimental evidences have been put forth to support the postulate that there are "glucoreceptors", sensitive to blood glucose and glucose utilization, in the hypothalamus. Gastrointestinal afferents, which carry information about the energy intake, reach the hypothalamic regions and interact with the glucose sensitive mechanisms. Available evidence suggests that obesity and decreased body weight, resulting from lesions of the hypothalamic 'satiety' and 'feeding' centres respectively, are not only due to altered food intake, but also to derangement in glucose homeostasis. The medial preoptic area does the fine tuning of energy balance (regulation of food intake) in response to alterations in the temperature, locomotor activity and sleep wakefulness. Thus the hypothalamus regulates energy balance through its control of energy intake on the one hand, and its expenditure and storage on the other. Neuroendocrine system and autonomic nervous system deal with storage and expenditure of energy.

Effects of long-term treatment with testosterone enanthate in rhesus monkeys: I. Pharmacokinetics of testosterone, testicular volume and liver metabolism of testosterone

The effects of long-term administration of testosterone enanthate on the pharmacokinetics and bioavailability of testosterone were studied in adult male rhesus monkeys (n = 9), injected with 50 mg of testosterone enanthate (TE) once every 14 days for a total of 32 months. Control animals were injected with 0.2 mL olive oil. Serum testosterone levels increased sharply within 24 h of the first injection of TE and reached a peak on day 3 followed by a sharp decline, but baseline values were not reached even by day 14. Subsequent injections of TE caused a similar pharmacokinetic profile until the 55th injection; testosterone levels on day 3 declined from the 56 to 58th injection and remained in a lower range until the last injection. Repeated injections of TE increased the bioavailability of testosterone as shown by the Area Under the Curve. The nocturnal (22.00 h) surge in testosterone levels during the pretreatment phase was abolished by TE injections. TE injections altered the metabolism of testosterone by the liver, as studied in vitro; while liver from control animals converted testosterone to androstenedione as the major metabolite, androsterone was the major metabolite in chronically TE-treated animals. Spermatogenesis and the associated increase in testicular volume observed in control animals in winter were suppressed in TE-treated animals. The results indicate that repeated TE injections elevate serum testosterone to supra-physiological levels with marked fluctuations in circulating testosterone levels after each injection. Possibly in response to these elevated levels, there was a change in the metabolism of testosterone by the liver as observed in vitro.

Effect of NMDA lesion of the medial preoptic neurons on sleep and other functions

This study was undertaken to determine the effects of the destruction of the medial preoptic area (mPOA) neurons by N-methyl D-aspartic acid (NMDA), on sleep-wakefulness (S-W), locomotor activity, body weight, rectal temperature, and food and water intake in rats. The NMDA lesion of the mPOA produced long-lasting insomnia with marked reduction in the deeper stages of sleep, including paradoxical sleep. The reduction in the duration of sleep episodes in the lesioned rats indicated their inability to maintain sleep. The insomnia resulting from a decreased sleep pressure did not alter the sleep-initiating ability. Though the day-night distribution of sleep remained largely unaffected, there was an increase in locomotor activity during the light period. There was no increase in food intake to compensate for the high energy expenditure resulting not only from hyperactivity but also from hyperthermia in the mPOA-lesioned rats. Thus, body weights of the rats were reduced even without any change in food and water intake. However, the changes in body temperature and locomotor activity after the mPOA neuronal loss may not have exerted a major influence on S-W, as the alterations in all these parameters had different time courses.

Recovery of sleep after fetal preoptic transplantation in medial preoptic area-lesioned rats

Changes in sleep after fetal preoptic (POA) tissue transplantation were studied in rats which had been made insomniac by a medial preoptic area (mPOA) lesion. Two days after the N-methyl D-aspartic acid (NMDA) lesion of the mPOA, fetal POA tissues (obtained from 14- to 17-day-old fetuses) were transplanted into the lesioned mPOA. Insomnia was less marked in these animals, as compared to nontransplanted lesioned rats, even on the 4th day after transplantation. The quantum of sleep nearly attained the prelesion level by the 20th day. Body weight also showed recovery after transplantation. Rectal temperature, which was increased by the lesion of the mPOA, remained unaltered even after the transplantation. These results suggest that the recovery of sleep and rectal temperature may follow different time courses. Surviving transplanted neurons were seen at the site of lesion on postmortem examination. Humoral interaction between the host and the transplant may be responsible for the early recovery of sleep, though the establishment of neural connections between the host and transplant might have contributed to the later recovery. This is the first study to show the recovery of sleep function in insomniac animals after fetal preoptic tissue transplantation. However, the specificity of the POA fetal tissue, in comparison with other neural tissues to promote sleep recovery, remains to be established.

The role of alpha-2 receptors in the medial preoptic area in the regulation of sleep-wakefulness and body temperature

The study was conducted on 48 free-moving male rats to find out the role of the medial preoptic alpha2 receptors in the regulation of sleep and body temperature. Recording electrodes for assessment of sleep-wakefulness, and injector cannulae for injection of drugs in the medial preoptic area were chronically fixed on the skulls of the animals. The noradrenergic fibres projecting to the medial preoptic area were destroyed in 24 rats by administration of 6-hydroxydopamine at the ventral noradrenergic bundle. Though arousal was produced in normal rats by the injection of the alpha2 adrenergic agonist, clonidine, at the medial preoptic area, it induced sedation in rats with noradrenergic fibre lesion. Clonidine did not alter the rectal temperature in normal rats but it induced hypothermia in lesioned rats. Injection of alpha2 antagonist, yohimbine, at the medial preoptic area induced sleep in rats with intact noradrenergic fibres. However, the sleep inducing effect of this drug was very much attenuated in the lesioned animals. There was no significant change in body temperature, in both these groups of animals, after yohimbine administration. The study indicates the role of presynaptic alpha2 adrenergic receptors in arousal response and indirectly supports the contention that the alpha1 postsynaptic receptors at the medial preoptic area are involved in hypnogenesis. It also suggests that the thermal changes induced by adrenergic system are mediated through alpha1 postsynaptic receptors. But the thermal changes do not contribute towards the induced alterations in sleep-wakefulness. It is proposed that there should be separate sets of noradrenergic terminals for regulation of sleep and body temperature.

Changes in magnetic resonance imaging and sex behavior after 6-OHDA injection in the medial preoptic area

Magnetic resonance imaging (MRI) of the brains of male rats was done before and after destroying the catecholamine (CA) fibers by local application of 6-hydroxydopamine (6-OHDA) in the medial preoptic area (mPOA). The male sexual behavior was also assessed before and after injection of this toxic drug. The administration of 6-OHDA (8 microg) resulted in highly variable lesions, as shown by MRI and confirmed by histological examination. A hyperintense area was visible either on one or on both sides, about 1-3 h after the administration of the drug. Postmortem histofluorescence showed destruction of CA fibers in the mPOA on those sides that showed hyperintense areas in the MRI. No CA fiber destruction was seen in those rats that had shown no change in MRI after 6-OHDA injection. There was a transient reduction in sex drive score in all the 6-OHDA-treated rats. The present findings point out a correlation between the MRI changes and CA fiber destruction, whereas the transient reduction in the sexual behavior was not related to these changes. It is suggested that some biochemical events related to 6-OHDA destruction of CA fibers may have been responsible for the hyperintensity seen in the MRI.

Toxic effect of systemic administration of low doses of the plasticizer di-(2-ethyl hexyl) phthalate [DEHP] in rats

DEHP [di-(2 ethyl hexyl) phthalate], a widely used plasticizer in blood storage bags, leaches out in appreciable amounts into blood (about 10 mg/100 ml) resulting in exposure of recipients of blood transfusion to this compound. Various reports indicate the toxicity of DEHP, particularly in liver and reproductive organs but all these studies used large doses (up to 2 g or more/Kg body weight) and oral route of administration which are not relevant to the intravenous administration during blood transfusion or the low amounts present in blood. We have studied changes in the activity of some important enzymes-gamma-GT, ALT, CPK, LDH, alkaline phosphatase, acid phosphatase, beta-glucuronidase and few other parameters like vitamin E, glutathione, serum albumin etc in rats administered low doses of DEHP (corresponding to transfusion of 2, 4, 6 and 10 units of blood). Histopathology of the organs has also been carried out. The results obtained indicate no serious toxic effects for DEHP at the level present in blood stored in DEHP plasticized blood bags as evidenced by the lack of any significant alteration in most of the biochemical parameters studied. Even in those cases where there was alteration (for e.g., decrease in the level of vitamin E) 24 hr after administration of DEHP, it returned to near normal level with in 72 hr to 7 days. No histopathological changes were observed in any of the organs at these levels of DEHP. It is concluded that DEHP did not cause any serious toxic effect even at doses corresponding to transfusion of several units of blood in a recipient.

Stroke recurrence in diabetics. Does control of blood glucose reduce risk?

BACKGROUND AND PURPOSE

Patients with diabetes are at increased risk of stroke. Risk might be reduced if blood glucose level were controlled.

METHODS

In a population-based study, we enrolled 621 patients within a month of an initial ischemic stroke and followed them regularly twice annually; 198 were diabetic. We monitored blood glucose level in 142 (72%) using glycosylated hemoglobin (HbAlc). Recurrent stroke frequency was determined by history, examination, and medical records. Cox proportional hazards models were used to examine the relationship between risk of recurrent stroke and HbAlc level. The models included interaction with time-dependent HbAlc level and history of diabetes, selected medical comorbidities, age, and sex. HbAlc level was analyzed as both a continuous and a dichotomous variable (ie, controlled versus uncontrolled); "controlled" was defined with different cut points.

RESULTS

All but 17 patients (12%) whose blood glucose was monitored were well controlled (HbAlc < 8%). HbAlc level was not associated with increased risk of stroke recurrence (hazard ratio [HR], 0.87 per 1% increment in HbAlc; 95% confidence interval [CI], 0.623 to 1.219), nor was there a trend toward increased risk of recurrent stroke as the cut point defining "controlled" increased: with HbAlc at < 6%, the HR for the uncontrolled group was 0.51 (95% CI, 0.176 to 1.503); at < 7%, it was 0.43 (95% CI, 0.089 to 1.923); and at < 8%, it was also 0.43 (95% CI, 0.057 to 3.317).

CONCLUSIONS

Among diabetic patients with an initial stroke, no association between HbAlc level over time and risk of stroke recurrence was found. However, most patients in this cohort were well controlled, and any adverse effect of poor control could not be adequately tested.

Role of medial preoptic area beta adrenoceptors in the regulation of sleep-wakefulness

The role of the medial preoptic area (mPOA) beta adrenergic receptors in the regulation of sleep-wakefulness (S-W) was investigated in this study. S-W was assessed on the basis of polygraphic recording of EEG, EMG and EOG in free moving rats. Intracerebral microinjection of beta agonist, isoproterenol, into the mPOA produced arousal. The study was also conducted on another set of rats in which noradrenergic (NE) innervation to the mPOA was destroyed by injecting 6-hydroxydopamine into the ventral noradrenergic bundle, in the brain stem. Local application of isoproterenol, into the mPOA, in these animals, did not produce any significant change in S-W. Thus, the increase in awake period obtained on isoproterenol administration was the result of its action on the presynaptic NE terminals. Possible involvement of other responses in the isoproterenol induced increase in wakefulness, is discussed.

Male sexual behaviour not abolished after medial preoptic lesion in adult rats

N-methyl-D-aspartic acid (NMDA) was injected into the medial preoptic area (mPOA) of 10 rats to destroy the neurones in this region. Male sexual behaviour was scored before, and on days 2, 6, 10, 17, 24 and 31 after the administration of NMDA. The neurones in the injection site were destroyed in all the rats, but male sexual behaviour was only transiently reduced in the animals with lesions largely restricted to the mPOA. These findings are in contrast to the earlier reports of permanent suppression of sexual behaviour after electrolytic lesion, with damage to the neurones and fibres of passage. The present study shows that the mating behaviour could be expressed even after the destruction of the neurones in the mPOA.

beta-adrenergic modulation of male sexual behavior elicited from the medial preoptic area in rats

This study was aimed at investigating the role of the adrenergic mechanism in the medial preoptic area (mPOA) in sexual arousal and copulatory performance. Saline, norepinephrine (NE), phenoxybenzamine (PBZ) and propranolol (PROP) were injected into the mPOA in different groups of rats. NE application (3 micrograms) facilitated the male sexual behavior by increasing sexual arousal and copulatory performance. On the other hand, application of PROP and PBZ produced inhibition of male sexual behavior. Effects produced by low doses of PROP were more significant than PBZ. The results, viewed in the light of other available reports, suggest that the mPOA beta-adrenergic mechanism is important in the elaboration of male sexual behavior.

Magnetic resonance imaging of temporal changes of neurotoxic lesion in the rat

Destruction of striatal neurons in the rat brain, induced by intracerebral injection of N-methyl D-aspartic acid (NMDA), has been visualized noninvasively by magnetic resonance imaging (MRI). The changes in images were monitored from 12 h to one month after the stereotaxic microinfusion of NMDA (10 micrograms in 0.4 microliter) into the striatum, using a T2-weighted rapid acquisition by relaxation enhancement (RARE) sequence. A localised hyperintense (bright) area was visible after 12 h at the site of the injection, and it persisted for the next three days. The size of the hyperintense area decreased thereafter and, after one week, the increased brightness was restricted to the lateral ventricle. Post-mortem histological examination, done after one month, showed a dilated lateral ventricle. The size and location of the lesioned area, identified in histological sections, corresponded to the hyperintense area observed during these initial days after NMDA lesion. The present study demonstrates that noninvasive MRI techniques, using a typical RARE sequence, offer a powerful tool for the early detection of neurotoxic lesion of the brain area, although some caution is required in its use for estimating the size of the lesioned area three days after its formation. The present findings indicate that, in long-term studies, alterations of the neighbouring structures, such as enlargement of the ventricular system, may confound the MRI evaluation of neurotoxic lesions in vivo.

Effect of application of gamma amino butyric acid at the medial preoptic area on sleep-wakefulness

Intracerebral microinjections of gamma amino butyric acid were given bilaterally at the medial preoptic area (mPOA) to determine the possible role of this neurotransmitter in the genesis and regulation of sleep-wakefulness. GABA (50 micrograms/0.2 microliters) when administered through chronically implanted cannulae in free moving rats, did not produce any significant alterations in sleep-wakefulness. This may be attributed either to the non-involvement of GABA at the level of mPOA in the regulation of sleep, or to other factors like the low dose and rapid breakdown of the injected drug.

Medial preoptic alpha-2 adrenoceptors in the regulation of sleep-wakefulness

Adrenergic alpha 2 agonist (clonidine) and its antagonist (yohimbine) were locally applied to the medial preoptic area (mPOA), to find out the role of alpha 2 receptors at this brain region in the regulation of sleep-wakefulness. Clonidine produced arousal, whereas yohimbine induced sleep in freely moving animals. Behavioural arousal produced by clonidine administration was accompanied by EEG synchronization. The alpha 2 receptor as the probable site of action of externally applied norepinephrine (NE), is discussed.

Effect of carbachol injection in the medial preoptic area on sleep-wakefulness and body temperature in free moving rats

The aim of the present study was to find out the changes in sleep-wakefulness and body temperature brought about by application of cholinergic agonist, carbachol, in the medial preoptic area (mPOA). Carbachol, when injected bilaterally into the mPOA of male rats, through chronically implanted cannulae, produced a fall in rectal temperature and long lasting arousal. There was temporal dissociation in the duration of changes produced in the two parameters. It is suggested that the cholinergic system at the medial preoptic area brings about arousal response and fall in body temperature through different circuits.

Sensory modulation of the medial preoptic area neuronal activity by dorsal penile nerve stimulation in rats

The study was aimed at finding out the influence exerted by the genital afferents on the medial preoptic area (mPOA), which plays a pivotal role in the regulation of male sex behavior. To fulfil this objective, the effects of stimulation of the dorsal penile nerve (DPN) on the activity of 82 mPOA neurons were studied. The base line firing rates of the mPOA neurons, studied by extracellular recording, ranged between 0.5 and 38.5 Hz (mean 7.18 +/- 7.91). The stimulation of the DPN (20 Hz, 0.4 msec. 70 microA) influenced 79.69% of the neurons studied. Though increased firing was the predominant influence produced (50%), decreased firing was also seen in a few (29.69%). The excited and inhibited neurons were randomly distributed within the mPOA. Neurons located in the lateral and posterior hypothalamus were not affected by the DPN stimulation. The stimulation parameters used in this study did not produce any change in the systemic arterial pressure and heart rate. The results provide electrophysiological evidence of afferent inputs from the male sex organ to the mPOA, which is an important area controlling male sex behavior.

Changes in sleep-wakefulness after kainic acid lesion of the preoptic area in rats

The role of the preoptic area (POA) neurons in the regulation of sleep-wakefulness (S-W) has been investigated in this study. The cell-specific neurotoxin, kainic acid (KA), was injected (0.8 microgram in 0.2 microliter) intracerebrally for lesioning of the POA. S-W was assessed (on the basis of EEG, EMG, and EOG recordings) for a day before bilateral lesion of the POA, and for 3 weeks after the lesion. There was an increase in wakefulness, and a decrease in all the stages of sleep after KA lesion of the POA. The reduction in deep slow wave sleep (S2) and REM sleep (PS) were more marked than light slow wave sleep (S1), and these had not shown any recovery even after 3 weeks of lesion. Two days after the lesion, the reduction in sleep was much more marked during the daytime than at night. There was an increase in locomotor activity, especially during the daytime, though it was only statistically significant on the 6th and the 10th day after the lesion. This study shows that the POA neurons are involved in the induction and maintenance of sleep. The lesion did not have a long lasting effect on the circadian distribution of sleep but the changes in locomotor activity seem to persist for a longer period.

A computer programme for recording male sex behaviour in rats

An accurate method of recording the frequencies of copulatory events, the latencies of initiation to copulation and the time spent in different behavioural categories is described. A microcomputer (IBM-PC) based data collection system for acquisition and analysis of male rodent sex behaviour has been developed. This software features ease of data entry and operation, using single key presses by assigning a preset code to each. Internal clock of the computer is made to function as a timer for accurate recording of latencies and intervals. A print out of the frequency or duration of data can be obtained either concurrently or after the completion of the experiment, as required. The least count of the technique is about 10(-4) min and this precludes its use for extremely rapidly changing behaviour.

Sleep-inducing function of noradrenergic fibers in the medial preoptic area

The aim of the investigation was to find out the role of noradrenergic (NE) terminals of the medial preoptic area (mPOA), in the regulation of sleep-wakefulness. Studies were conducted on free-moving adult male rats with chronically implanted cannulae in the mPOA. Sleep-wakefulness was assessed on the basis of EEG, EMG, and EOG recordings along with behavioral observations. Lesioning of catecholamine terminals (with 6-hydroxydopamine) in the mPOA produced an increase in quiet wakefulness. Prevention of NE fiber destruction, by pretreating the rats with imipramine, prevented this effect. This demonstrated that the increased quiet wakefulness produced by 6-OHDA was the result of NE fiber destruction. Changes in sleep-wakefulness were also assessed after microinjection of NE into the mPOA, in normal and ventral noradrenergic bundle (VNA)-lesioned rats. NE administration induced sleep in VNA-lesioned rats, and arousal in normal rats. The findings suggest that the NE terminals in the mPOA, projecting via VNA, play a role in the induction of sleep.

Fetal brain transplantation in kainic acid lesioned caudate nucleus of adult rats

This study confirmed that bilateral kainic acid (KA) injection at the caudate produces aphagia and adipsia in rats. The reduction in food and water intake was fatal after a higher dosage of the drug. To test the effect of transplantation on the mortality rate, KA was first injected in the left caudate, in one set of rats. After a gap of three days, fetal striatal tissue was unilaterally transplanted at this lesioned site, along with a second injection of KA in the right caudate. Successful transplantation, as ascertained morphologically, did not significantly alter the mortality rate. The morphometric study revealed that the neurons of the transplant were larger in size, and their numerical density lower than those of the caudate of normal rats. Only very few neurons of the transplant developed functional connectivity with the host, as demonstrated by electrophysiological studies.

Effect of rapid eye movement sleep deprivation on sexual behaviour of male rats

Rapid eye movement sleep deprivation for 3 to 4 days by the platform pedestal procedure produced an increase in sexual behaviour of male rats. The possible factors contributing towards the increase in sexual behaviour are discussed.

REM sleep deprivation and food intake

The effect of REM-sleep deprivation (REM-SD) on diet preference was studied in rats. REM-SD for a period of 72 hrs produced an increase in day, night and 24 hrs (day plus night) intakes of Carbohydrate Rich diet (CRD) and Total diet (TD). Body weight (BWt) was also increased. The maximum increase in the above parameters were recorded on the 2nd day of REM-SD. During recovery period the intakes of TD fully recovered, but the BWt and consumption of CRD remained high. Intakes of Balanced diet (BD) remained significantly on the lower side when compared to the pre REM-SD mean values. During REM-SD, the rats preferred CRD than BD. The body temperature did not show any change. The increase in TD intake and BWt could be the result of an increase in insulin level and the change appears to be mediated by the activation of hypothalamic feeding centre.

The role of reticular activating system in altering medial preoptic neuronal activity in anesthetized rats

The influence of the ascending reticular activating system (ARAS) on the medial preoptic unit activity was studied in urethane anesthetized rats. Alterations in the unit activity were also correlated with cortical EEG changes. A fourth of the medial preoptic units showed alterations in their discharges with cortical EEG changes. These units were also influenced by high frequency stimulation of ARAS, which simultaneously produced EEG desynchronization. On the other hand they were generally not influenced by 1 Hz stimulation of ARAS. These results indicate that the anatomically demonstrated projections from midbrain (forming ARAS), involving very few synapses, may not be involved in the regulation of sleep-wakeful function of the medial preoptic area. Interaction of some of the inputs at the medial preoptic area is discussed.

Correlation of preoptic neuronal activity with spontaneous and induced cortical EEG changes

Preoptic area has neurons which change their firing rate along with spontaneous alterations of the cortical EEG between synchronization and desynchronization. The cortical EEG synchronization and desynchronization could be induced by stimulation of the caudal and the rostral brain stem respectively. This study was aimed at finding out whether stimulation of the brain stem structures produce the same change in the unit activity as that occurring during spontaneous alteration of the EEG. The changes in unit activity showed some concordance and dissociation between spontaneous and induced EEG alterations. The possible interaction of inputs from cortex and brain stem at the level of the preoptic area is discussed.

Interrelationship of thermal and sleep-wakefulness changes elicited from the medial preoptic area in rats

The study investigated the possible interrelationship between changes in sleep-wakefulness and body temperature, primarily induced by manipulation of the noradrenergic system in the medial preoptic area. Saline, norepinephrine, and its alpha- and beta-blockers were injected in the medial preoptic area and in some control areas of rats, during their sleeping and active periods. 5-Hydroxytryptamine was injected in the medial preoptic area in another group of animals. Simultaneous changes in sleep-wakefulness and the body temperature were continuously recorded. Norepinephrine produced hypothermia and arousal, whereas alpha-adrenergic blockers induced hyperthermia and sleep. These changes in body temperature and in sleep-wakefulness did not follow an identical time course. 5-Hydroxytryptamine induced hyperthermia without affecting sleep-wakefulness. It is suggested that there are different neuronal mechanisms in the medial preoptic area that bring about the drug-induced changes in temperature and sleep-wakefulness.