Olfaction and human neonatal behaviour: clinical implications

About 1-2% of the human genome is allocated to production of receptors for the olfactory epithelium-a hint as to the possible importance of this chemical sense, which includes two anatomically distinct systems: the main olfactory system with sensory cells located in the upper part of the nasal cavity, and the vomero-nasal organ with sensory cells on the nasal septum. In adults, individual odours may influence mate preferences and a growing body of evidence indicates that naturally occurring odours play an important role in the mediation of the infant's behaviour. Even foetal olfactory learning seems to occur and breast odours from the mother exert a pheromone-like effect at the newborn's first attempt to locate the nipple. Newborns are generally responsive to breast odours produced by lactating women. Olfactory recognition may be implicated in the early stages of the mother-infant attachment process, when the newborns learn to recognize the own mother's unique odour signature-a process possibly facilitated by the high norepinephrine release and the arousal of the locus coeruleus at birth. New knowledge about human odour physiology may have diagnostic and therapeutic implications-the initiation and stabilization of breastfeeding and termination of apnoeic spells are mentioned as examples.     

Autoradiographic localization of 2[125I]iodomelatonin binding sites in the gastrointestinal tract of mammals including humans and birds

ABSTRACT: In-vitro autoradiography was utilized to compare the distribution of 2[¹²⁵I]iodomelatonin binding sites or putative melatonin receptors in the gastrointestinal tracts of humans, guinea pigs, mice, rats, hamsters, rabbits, ducks, chickens, pigeons, and quail. In humans, binding was detected in the mucosa of the colon, caecum, appendix, and on their blood vessels but not in the ileum. In the other mammals, significant binding was only demonstrated in the mucosa of the rabbit rectum, mouse colon, mouse rectum, and guinea pig ileum. The distribution of 2[¹²⁵I]iodomelatonin binding in the avian gut varied with species. In the esophagus, binding was present in the lamina propria and blood vessels of all four birds. However, only the lamina propria of the chicken and quail proventriculus and ventriculus showed positive binding. For the duodenum and ileum, binding was very strong in the duck lamina propria, weak in the chicken lamina propria, and absent in the quail. In contrast, the pigeon muscle layer was weakly positive. The most striking species difference was found in the caecum where the duck lamina propria showed very strong binding, while the chicken lamina propria was only weakly positive. Conversely, the caecal muscle layer was strongly positive in chicken and quail but negative in duck and pigeon. In the rectum, a similar but less intense pattern of distribution was observed. The tremendous diversity in the distribution of 2[¹²⁵I]iodomelatonin binding sites in the gastrointestinal tract is in accord with the hypothesis that melatonin may serve different functions in the gut of different species.     

The clinical features of immunoglobulin light-chain (AL) amyloidosis with heart involvement

We reviewed clinical presentation, investigations, therapy, prognosis and outcome of 232 patients with primary (AL) cardiac amyloidosis. There were 142 men and 90 women. Median age at presentation was 59 years (range 29-85). AL heart disease was unusual both in patients under the age of 40 (3.0%) and in non-Caucasians (6.5%). Fatigue and weakness were the commonest presenting symptoms. Hallmark features of periorbital ecchymoses and macroglossia were present in 12.5% and 27.2%, respectively. AL cardiac amyloidosis was unusual in isolation (3.9%), and most frequently patients had features of multiorgan dysfunction; heavy proteinuria and features of malabsorption predominating in this respect. Heart involvement represents the worst prognostic indicator, with a median survival from diagnosis of 1.08 years, falling to 0.75 years with the onset of heart failure. Current therapeutic procedures appear to prolong survival, with left ventricular wall thickness, mass and ejection fraction on echocardiography and late potentials on signal averaged electrocardiography of use in prognostic stratification. Cardiac involvement from AL amyloidosis is rapidly fatal. It should be suspected in all patients with heart failure who have wall thickening on echo, normal chamber sizes, low EKG voltages and evidence suggesting a multisystem disease.      

Transient streamlines: texture synthesis for in vivo flow visualisation

Magnetic resonance (MR) imaging is a versatile technique for providing detailed information on blood vessel morphology and function. With its ability to acquire multi-dimensional cine flow data, MR is also an important tool for providing insight into blood flow patterns in vivo. The purpose of this paper is to describe the application of texture synthesis for flow visualisation. Two related issues are addressed, one is the removal of image noise from the acquired velocity data to ensure a correct representation of the underlying flow structure, and the other is the formation of transient streamlines through flow texture synthesis. The process of noise removal is achieved by using a convex projection algorithm based on the principle of mass conservation, whereas transient streamlines are formed via an iterative orientated pattern formation and enhancement procedure. The method described provides realistic visualisation of the flow patterns and avoids distortions caused by integration errors associated with conventional streamline tracking techniques. Effectiveness of the method applied to MR flow data acquired in healthy volunteers and patients is demonstrated.     

Flow patterns in the dilated ischemic left ventricle studied by MR imaging with velocity vector mapping

Magnetic reaonance velocity vector mapping was used to study flow patterns in dilated and healthy left ventricles. Eleven patients (age mean ± SD, 67 ± 12 yeare) with dilated left ventricle resulting from coronary artery diclease and 10 healthy volunteers (age 50 ± 9) were studied. Cine gradient echo images were acquired in the left ventricle vertical and horizontal long axes. Vertical and horizontal velocity components in the horizontal long axis plane of the left ventricle were encoded simultaneously. Maps of velocity components were then processed into multiple computer generated streaks whose orientation and length corresponded to velocity vectors. The following parameters (mean ± SD) differed significantly between the two groups: The heart rate (patients 70 211 beat/min. controls 57 ± 8, P <.001). end-diastolic volume (patients 264 ± 83 ml. controls 143 ± 26 ml. P <.001). ejection fraction (patients 31% ± 7, controls 61% ± 6, P < .MI), diameter of the Mow stream (patients 1.7 ± 0.6 cm. controls 3.2 2 0.3 cm. P <.001). In normal subjects the predominant direction of diastouc now through the mitd valve was toward the apex with short-lived vortices curling back behind each mitral ldet. The vortex beneath the anterior leaflet tended to be larger and more dominant. In patients with dilated left ventricle, the inflow was directed toward the free wall, giving rise to a well developed circular flow pattern turning back toward the septum and outflow tract and persisting through diastole. Magnetic resonance velocity vector mapping is an excellent method for studying left ventricular flow patterns. We have studied flow patterns in healthy volunteers and demonstrated abnormalities in patients with dilated left ventriclea resulting from coronary artery disease.