Stimulation of the lateral habenula inhibits dopamine-containing neurons in the substantia nigra and ventral tegmental area of the rat

Neurons in the lateral habenula (LHb) of rats have efferent projections that terminate in the substantia nigra pars compacta (SNC) and ventral tegmental area (VTA), where cell bodies of dopamine-containing neurons are located. In order to study the influence of the habenula on dopaminergic activity, single-cell electrophysiological techniques were used to record unit discharge of dopamine-containing neurons in the SNC and VTA during electrical stimulation of the LHb or adjacent structures. Dopamine-containing neurons in the SNC and VTA were identified by their characteristic spike duration (greater than 2 msec), discharge rate (2-8 spikes/sec), and irregular firing pattern. Analysis of peristimulus time histograms showed that 85% of SNC cells and 91% of VTA neurons were inhibited after single pulse stimulation (0.25 mA, 0.1 msec) of the LHb. The mean time between stimulation and onset of inhibition was 11 msec (range, 2-22 msec) and mean duration of maximal suppression was 76 msec (range, 20-250 msec). Stimulation of structures adjacent to the LHb (hippocampus, lateral thalamus, medial dorsal thalamus, medial habenula) had little or no effect. Destruction of the fasciculus retroflexus, the fiber pathway that contains most habenular efferents, blocked the stimulation effects on dopamine-containing neurons. Destruction of the stria medullaris, which contains most habenular afferents, did not alter the inhibitory effect of habenular stimulation. Injection of a cytotoxin, kainic acid, in the LHb 1 week before recording sessions blocked the inhibitory consequences of habenular stimulation. These experiments show that activation of neuronal perikarya in the LHb causes orthodromic inhibition of dopamine-containing neurons in SNC and VTA via the fasciculus retroflexus.     

Mercury,Lead and Copper in Feathers and Excreta of Small Passerine Species in Relation to Foraging Guilds and Age of Feathers

In the present study excreta and feathers of five species of adult passerine birds from Montepulciano wetland (Siena, Italy) were assayed for trace elements between January and August 2006. Lead concentrations varied from 16.31 to 26.50 mg/kg and were found strictly related to the age of feathers. Copper levels were found to be high mainly in insectivorous birds (9.68 mg/kg) and were probably influenced by local use of copper-based agricultural fungicides. Mercury accumulation in feathers varied between species from 0.08 to 0.73 mg/kg. The role of feeding habits on trace elements levels in feathers and excreta is discussed.     

Sentinel lymph nodes in cancer of the oral cavity – isolated tumour cells

BACKGROUND: Sentinel lymph node biopsy, step sectioning and immunohistochemistry have changed detection of tumour deposits. Isolated tumour cells (ITC) are detected more frequently than earlier because of a changed level of detection. METHODS: A total of 108 sentinel lymph nodes from 30 patients with T1/T2 cN0 oral cancer were re-classified histologically to find possible ITC and to describe technical pitfalls. RESULTS: Primarily we found metastatic spread in 12 of 108 sentinel lymph nodes: five macrometastasis and seven micrometastasis. After re-classification, we found seven lymph nodes with macrometastasis, five with micrometastasis and two with ITC. CONCLUSION: The ITC are probably precursors of micrometastasis waiting to grow and should be treated as such. Benign inclusions and dendritic cells did not cause problems, but can mimic ITC.     

Regulatory detoxication responses in Gobiidae experimentally exposed to PCBs

In order to investigate interspecific responses to pollutants, physiological and biochemical parameters were studied in two species of Gobiidae under both natural and experimental conditions. Gobius niger, collected in a polluted area, had higher mixed function oxidases activity and polychlorobiphenyl (PCB) residues than another species, Zosterisessor ophiocephalus, collected from a relatively clean lagoon. After acclimatization to clean water and exposure to PCBs (Aroclor 1260), both species showed responses similar to those observed in the field and all biochemical parameters related to detoxication were much higher in G. niger. This suggests that this species undergoes metabolic or genetic adaptation.     

Negotiating sleep: a qualitative study of new mothers

OBJECTIVE: The purpose of this qualitative study was to learn from 20 mothers about their experience of sleep during pregnancy and the immediate months of becoming a new mother. The study was part of a larger randomized clinical trial on an intervention to improve sleep and well-being among new mothers. METHODS: Semistructured, audiotaped interviews were conducted in which women were asked to describe the continuum of the sleep experience across the pregnancy and early postpartum and to describe strategies they found helpful as they established sleep patterns with their infant. Narrative analysis was used to interpret their stories, and data were managed with Atlas.ti qualitative software. RESULTS AND CONCLUSIONS: Sleep disturbances were common to all of the mothers, and sleep became a negotiated behavior as they adjusted to the mothering role. All of the mothers were surprised at the level of disturbance and exhaustion they experienced. Strategies included enlistment of partners to facilitate naps, development of a "sleep consciousness," and bed-sharing. Mercer's stages of becoming a mother are used to describe the process of incorporating sleep changes into their lives.     

Breast-feeding increases sleep duration of new parents

OBJECTIVES: This study describes sleep patterns for mothers and fathers after the birth of their first child and compares exclusive breast-feeding families with parents who used supplementation during the evening or night at 3 months postpartum. METHODS: As part of a randomized clinical trial, the study utilized infant feeding and sleep data at 3 months postpartum from 133 new mothers and fathers. Infant feeding type (breast milk or formula) was determined from parent diaries. Sleep was measured objectively using wrist actigraphy and subjectively using diaries. Lee's General Sleep Disturbance Scale was used to estimate perceived sleep disturbance. RESULTS: Parents of infants who were breastfed in the evening and/or at night slept an average of 40-45 minutes more than parents of infants given formula. Parents of infants given formula at night also self-reported more sleep disturbance than parents of infants who were exclusively breast-fed at night. CONCLUSIONS: Parents who supplement their infant feeding with formula under the impression that they will get more sleep should be encouraged to continue breast-feeding because sleep loss of more than 30 minutes each night can begin to affect daytime functioning, particularly in those parents who return to work.