Moving with the sun

A global 24-hour telemedicine conference entitled, "Moving with the Sun" was successfully completed on June 30 and July 1 1997 between participants from Hong Kong and China, as well as with sixteen major international medical centres around the globe. In addition to celebrating the return of Hong Kong to the People's Republic of China, the conference also signified the establishment of the Chinese University of Hong Kong, and Hong Kong as a bridge between Western countries and the PRC.     

Waking with the hypothalamus

An essential component of the whole-body homoeostasis provided by the hypothalamus is the management of available energy. This includes the regulation of sleeping and waking, feeding and drinking, body temperature and activity, as well as the endocrinium. The waking brain, in particular the cerebral cortex, needs to be activated through neuronal pathways ascending from the brainstem reticular formation (ascending reticular activating system, ARAS) and reaching the cortical structures by a dorsal route through the thalamus and a ventral route, including the hypothalamus and the basal forebrain. This review concentrates on the more recently explored ventral route and the hypothalamus with its different regions involved in the control of the waking state.     

Grasping with the eyes

When observing someone else acting on an object, people implement goal-specific eye movement programs that are driven by their own motor representation of the observed action. Usually, however, we observe people acting in contexts where more objects, different in shape and size, are present. Is our brain able to select the intended target even when there are different objects in the visual scene? And if this is the case, what kind of information does our motor system capitalize on? We recorded eye movements while participants observed an actor reaching for and grasping one of two objects requiring two different kinds of grip to be picked up. In a control condition, the actor merely reached for and touched one of the two objects without preshaping her hand according to the target features. Results showed higher accuracy and earlier saccadic movements when participants observed an actually grasping hand than when they observed a mere reaching hand devoid of any kind of target-related preshaping. This clearly suggests that the hand preshaping provided the observer with enough motor cues to proactively and reliably saccade toward the object to be grasped, thus identifying it even when the action target was not previously known. Our findings strongly corroborate the direct matching hypothesis suggesting that in processing others' actions, we take advantage of the same motor knowledge that enables us to efficiently perform those actions.     

胰腺损伤合并主胰管断裂44例诊治分析

目的分析严重胰腺外伤患者的临床表现及处理方法，探讨严重胰腺外伤的诊治对策。方法回顾性分析44例严重胰腺损伤并同时合并主胰管断裂患者的临床资料及救治经过，根据胰腺损伤的严重程度而选择不同的手术方式。结果CT检查对胰腺闭合性损伤确诊率可高达100％。本组患者均行手术治疗，远端胰腺空肠Roux-Y吻合术27例，改良十二指肠憩室化和十二指肠空肠Roux-Y吻合术3例，胰十二指肠切除2例。41例患者经救治均痊愈出院。并发症发生率为29．5％，死亡率为6．8％。结论胰腺损伤临床表现隐蔽，CT可提高术前确诊率。提高术前诊断率、及时和选择合理的手术方式、加强手术并发症的预防与治疗是降低严重胰腺外伤患者死亡率的关键。     

The Regulation of the Body-temperature during Work Performed with the Arms and with the Legs.

Experiments were performed in which the increase in rectal temperature was measured during ergometer exercise with the arms and with the legs. It was found that at a given output of energy, and at a given production of heat, the increase in temperature was larger with leg-work than with arm-work. Temperature measurements in the stomach showed that this difference was not due to the proximity during leg-work of the working muscles to the measuring thermocouple. Experiments with leg-work a t sea level and a t a simulated alti-tude of 4,000 m showed no difference in the temperature increase, indicating that a more anaerobic condition and a more pronounced subjective feeling of strain have no effect on the thermoregulatingcentre during work. It is concluded that the different “setting” of the heat dissi-pating centre during work with the arms and with the legs possibly is due to a different set of nervous impulses, efferent and reflex, reaching the centre during the two kinds of work.     

Lactoferrin Inhibits the Endotoxin Interaction with CD14 by Competition with the Lipopolysaccharide-Binding Protein

Human lactoferrin (hLf), a glycoprotein released from neutrophil granules during inflammation, and the lipopolysaccharide (LPS)-binding protein (LBP), an acute-phase serum protein, are known to bind to the lipid A of LPS. The LPS-binding sites are located in the N-terminal regions of both proteins, at amino acid residues 28 to 34 of hLf and 91 to 108 of LBP. Both of these proteins modulate endotoxin activities, but they possess biologically antagonistic properties. In this study, we have investigated the competition between hLf and recombinant human LBP (rhLBP) for the binding of Escherichia coli 055:B5 LPS to the differentiated monocytic THP-1 cell line. Our studies revealed that hLf prevented the rhLBP-mediated binding of LPS to the CD14 receptor on cells. Maximal inhibition of LPS-cell interactions by hLf was raised when both hLf and rhLBP were simultaneously added to LPS or when hLf and LPS were mixed with cells 30 min prior to the incubation with rhLBP. However, when hLf was added 30 min after the interaction of rhLBP with LPS, the binding of the rhLPS-LBP complex to CD14 could not be reversed. These observations indicate that hLf competes with rhLBP for the LPS binding and therefore interferes with the interaction of LPS with CD14. Furthermore, experiments involving competitive binding of the rhLBP-LPS complex to cells with two recombinant mutated hLfs show that in addition to residues 28 to 34, another basic cluster which contains residues 1 to 5 of hLf competes for the binding to LPS. Basic sequences homologous to residues 28 to 34 of hLf were evidenced on LPS-binding proteins such as LBP, bactericidal/permeability-increasing protein, and Limulus anti-LPS factor.     

Remembering the past with slow breathing associated with activity in the parahippocampus and amygdala

Breathing plays an important role in perception of odors and the experience of emotions. We used the dipole tracing method to analyze brain areas related to odor-induced autobiographical memory and emotions estimated from averaged electroencephalograms triggered by inspiration onset during odor presentation. Odor stimuli were perfumes subjects named that elicited a specific, pleasant and personal memory as well as two pleasant odors for controls. The perfumes induced specific emotional responses during memory retrieval, arousal level of the memory, feelings of pleasantness and a sense of familiarity with the odor. Respiration measurement indicated that tidal volume increased and respiratory frequency decreased during presentation of perfume stimuli, showing a deep and slow breathing pattern. Throughout the olfactory stimulation, electroencephalograms and respiration were simultaneously recorded. In the averaged potentials, low frequency oscillation was phase-locked to inspiration. Dipole analysis showed that perfumes activated more widespread areas of the right parahippocampal cortex and converged in the right amygdala compared to control odors. Slow breathing synchronized with odor-induced autobiographical memory and emotions may be subconsciously stored in the parahippocampal cortex and amygdala.     

Experimenting with the acting self

Recent neuroscientific research has developed the concept of the embodied agent as a scientifically viable approach to the psychological concept of the self. Both the awareness of one's own actions and awareness of one's own body are necessary conditions for the experience of selfhood. The relative contributions of efferent and afferent information in self-awareness are yet to be fully understood. We review experimental evidence that highlights the phenomenological and functional differences between the "acting self" and the "sensory self." These differences may underlie the ubiquitous modulation of perception in voluntary action. We focus on three main research fields: somatosensory perception, time-awareness, and self-recognition. A series of experiments, designed so as to dissociate afferent from efferent information, are reviewed. As a whole the results suggest that intentional action functions as a general context for awareness, modulating the perception of one's own body. The "acting self," owner of the efferent information, modulates the phenomenal experience of the "sensory self" because of the intrinsically agentic nature of voluntary movement. Finally, it is suggested that this sense of agency is efferent-driven, originating from pre-action processes.