Clinical MR imaging with a Helmholtz-type surface coil

Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.     

Comparative inotropic effect of calcium, endothelin-1, and forskolin on ferret papillary muscles during acidosis

Summary— Acidosis affects multiple steps in the excitation-contraction coupling pathway of myocardium, producing decreased calcium sensitivity of myofibrils and modification of the function of the sarcoplasmic reticulum. Our aim was to evaluate the effectiveness of three different classes of inotropic agents under acidotic conditions: 1) forskolin, an adenylate cyclase activator that enhances cellular cyclic AMP concentrations, 2) elevated extracellular Ca²⁺ and 3) endothelin-1, an activator of the inositol triphosphate, diacylglycerol pathway. Ferret papillary muscles were mounted in organ baths containing normal physiological solution (pH = 7.4). After baseline tension was measured, the muscles were bathed in an acidotic solution (pH = 6.98) that decreased tension to 40% of the control; subsequently, the muscles were washed with normal physiological solution until they returned to baseline. Each inotropic agent was added to the bathing solution in a concentration sufficient to increase tension by 40% above the baseline. Then the solution was made acidotic (pH = 6.98) in the continuous presence of that concentration of inotropic agent and the resultant steady-state developed tension measured. The increases in tension induced by each inotropic agent at normal pH were adjusted to be similar; in contrast, the response to each drug in acidosis was significantly different. Under acidotic conditions, endothelin-1 was the most effective inotropic agent in restoring the depressed developed tension. This was possibly due to enhancement of the myofilament sensitivity to Ca²⁺, which was more effective than increasing [Ca²⁺]_i through elevating extracellular Ca²⁺ or the addition of forskolin which increased [Ca²⁺]_i but desensitized the myofilaments to Ca²⁺.     

Shared care: a review of the literature

This review examines broad issues of concern regarding the primary/secondarycare interface. The main purpose was to identify areas of goodpractice which could be adapted for more general use. One ofthe most fundamental aspects identified was communication, whichis discussed in some detail. Also covered are shared prescribingand disease management. The data suggest that the most effectivesystem(s) of shared care has yet to be established. Furtherqualitative and economic evaluations are required, taking intoaccount patient preferences. Although the literature does describecertain practice exemplars, it is clear that inter- and intra-professionalcommunication continues to be a problem. Whilst informationtechnology may provide some of the solutions, it is concludedthat a culture change, which compels health professionals tomake sharing of patient information a much higher priority,is reauired. Keywords. Shared care, seamless care, hospital, general practice, family practice.     

Selection for increased pheromone response in the male pink bollworm,Pectinophora gossypiella (lepidoptera: Gelechiidae)

The genetic basis of the duration and incidence of male wing fanning to pheromone in the pink bollworm moth,Pectinophora gossypiella (Saunders), was examined by artificial selection. Using a still-air bioassay, males from a laboratory colony were selected for increased duration of wing fanning when exposed to a 6535 blend of (Z,E)- and (Z,Z)-7,11-hexadecadienyl acetates. The mean (±SE) duration of wing fanning in the selected line increased from 5.4±1.4 to 17.4±2.7 s after six generations. The increase in wing fanning duration was the result of an increase in response duration among responders and not the percentage of males that responded. Realized heritability of wing-fanning duration was 0.16±0.02. The amount and ratio of pheromone produced by females in the male-selected line did not change.This research was supported in part by NSF Grant PCM-8309398 and a University of Massachusetts Biomedical Research Grant.     

Central nervous system neurons labelled following the injection of pseudorabies virus into the rat urinary bladder.

Pseudorabies virus was injected into the wall of the urinary bladder and, following incubation times of 2, 3 and 4 days, central nervous tissue was processed immunohistochemically for the presence of virus. Longer incubation times resulted in more extensive spread of the virus. Infected neurons were initially found in the spinal cord (mainly lumbosacral) and, after longer survival times, in raphe nuclei, reticular area, pontine micturition center, locus coeruleus, red nucleus, hypothalamus, preoptic, and cortical areas. These data define a multisynaptic circuit of neurons whose ultimate output influences urinary bladder function.     

Blood supply of the olfactory nerve

Summary The authors report the results of a series of dissections and anatomic sections of the fronto-basal region of the brain and of the anterior cranial fossa in human cadavers. The constant presence of an arachnoidal cistern above the olfactory nerve was verified. The arachnoid separates from the pial membrane and forms a bridge with the ventral part of the olfactory bulb and tract, from the lateral edge of the olfactory sulcus to the medial edge of the gyrus rectus. The cistern is wide in its anterior portion, between the gyrus rectus and the olfactory bulb, and is reduced to a virtual slit in its posterior portion where the tract is lodged in the olfactory sulcus. The olfactory nerve can be separated without damaging fronto-basal arachnoidial adhesions over several centimeters. Dissection of this region after intravascular injection of colored media shows the constant presence of an artery destined to the olfactory bulb and tract. It originates either from the lateral surface of the anterior cerebral a. (segment A2), or from the medial fronto-basal a., and consistently provides terminal branches in front of the olfactory trigone in the medial olfactory sulcus. At their ventral extremity, the olfactory structures are therefore vascularised independently for several centimeters, from the lower face of the frontal lobe. The independent vascularisation of the olfactory nerve, the tenuous and easily detachable adhesions, and the actual presence of a true arachnoidal cistern all contribute to enabling surgical techniques which conserve olfactory function during anterior approaches.

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Vascularisation du nerf olfactif. Rapports méningés et applications chirurgicales

Résumé Les auteurs rapportent les résultats d'une série de dissections et de coupes de la région fronto-basale de l'encéphale et de la fosse crânienne antérieure sur sujets cadavériques. La présence constante d'une citerne arachnoïdienne au dessus du n. olfactif a été vérifiée. L'arachnoïde se sépare du feuillet pial et passe en pont à la partie ventrale du bulbe et du tractus olfactifs, du bord latéral du sillon olfactif au bord médial du gyrus rectus. La citerne est large dans sa portion antérieure, entre le gyrus rectus et le bulbe olfactif, se réduit à une fente virtuelle postérieure lorsque le tractus se loge dans le sillon olfactif. Le n. olfactif peut être séparé sans dommage des adhérences arachnoïdiennes fronto-basales sur quelques centimètres. La dissection de cette région, après injection intravasculaire de masses colorées montre, de façon originale, la présence constante d'une artère destinée au tractus et au bulbe olfactifs. Elle naît soit de la face latérale de l'a. cérébrale antérieure (segment A2), soit de l'a. fronto-basale médiale, pour donner ses branches terminales toujours en avant du trigone olfactif dans le sillon orbitaire médial. Sur quelques centimètres à leur extrémité ventrale, les structures olfactives ont donc une vascularisation indépendante de la face inférieure du lobe frontal. L'indépendance vasculaire du n. olfactif, des adhérences ténues, facilement détachables, et la réalité vérifiée d'une véritable citerne arachnoïdienne permettent d'imaginer des techniques conservatrices de la fonction olfactive utilisées dans plusieurs indications de la chirurgie de la fosse crânienne antérieure.

     

Chronic myelomonocytic leukemia: an ultrastructural study by transmission and scanning electron microscopy.

The hematologic findings in three cases of chronic myelomonocytic leukemia are presented, with results of ultrastructural studies by transmission and scanning electron microscopy on two of the cases. In the peripheral blood there was a dual, non-lymphocytic, markedly increased population of granulocytes and monocytes. The granulocytes showed marked nuclear abnormality and nuclear cytoplasmic organelle asynchrony. In the marrow the majority of the cells appeared granulocytic but atypical forms and intermediate difficult to distinguish from monocyte precursors were evident by electron microscopy. The ultrastructural findings lend some support to the concept that the neoplastic granulocytes and monocytes having a common precursor.     

Improved oocyte quality is obtained with follicle stimulating hormone alone than with follicle stimulating hormone/human menopausal gonadotrophin combination

The aim of this study was to compare the efficacy of pure follicle stimulating hormone (FSH) with that of FSH/human menopausal gonadotrophin (HMG) combination in downregulated cycles. A total of 357 patients was evaluated retrospectively. Sixty percent of patients in the FSH group and 55% in the FSH/HMG group were new; the others were repeat patients. Ovulation was suppressed with leuprolide acetate in all patients, followed by either FSH (n = 218) or FSH/HMG (n = 119). There was no difference in patients' age, infertility factors, number of ampoules used, length of stimulation, oestradiol levels on day of human chorionic gonadotrophin (HCG) administration, number of oocytes recovered or the number of embryos transferred. Also, nuclear maturity at aspiration and fertilization rates were not different between the two groups. FSH stimulation resulted in a significantly higher percentage of mature oocytes that showed the typical 'mature' morphological characteristics (P < 0.0001). The clinical pregnancy rates per transfer were 40 and 28% in patients stimulated with pure FSH and FSH/HMG respectively (P < 0.05). The significantly higher number of immature oocytes matured in vitro in the FSH/HMG group (P = 0.001) suggests a possible effect on in-vitro maturation, due to luteinizing hormone present in HMG. The difference in mature oocyte quality may be an important determinant in the higher pregnancy rates for the FSH- stimulated patients.